DXT-MON vs. Neumann KH-120A ... or "How far can I get with DIY and where are the limits"

kh_120a_vs_dxt_mon_1240Once the following question was asked in the hifi forum:

"How far can I get with DIY and where are the limits?"

The "critical question" was whether it would be possible to top or equal the active monitor KH-120A, presentet by Neumann, with a budget <= 1300 € / pair / active, what was the price of the KH-120A, with comparable dimensions.

Well, the thread ran for a long time, it was discussed intensely, argued but also worked constructively. If you are very interested in the whole story, you may want to read the thread in the forum, but we can also make it short:

DXT-MON is the only construct arose from this thread that was succresfully finished, and complied with the conditions of the Battle, and was developed with the aim to outperform the Neumann KH-120A. To clarify whether this finally succeeded or not is the aim of this article. Of course it is not easy for me, as a participant, to make an objective judgment. But since there is no comparison of these two speakers, except the one I've done, there's nothing left for me to try anyway ...

In the following now the comparison of the two speakers. All measurements were made under identical conditions. Nothing was whitewashed, added, or poised. The pair DXT-MON was activated with a Hypex AS 2.100 module. There were no filters set. The measurements are shown in animated GIFs, with picture changes every ~ 3 seconds between the two speakers.

Directivity horizontal

Frequency response 0-90 ° in 15 ° steps

Both speakers have a very uniform horizontal dispersion. DXT-MON tends to be broader. In terms of balance, in my opinion, none of the two are considered better => draw at a very high level!

At this point, the topic "linearity" may also be dealt quickly:

without big words: draw

Directional behavior vertical


It gets a bit more difficult because both candidates have inherent weaknesses. Both show a cut-off at the crossover frequency and a sidelobe at 3kHz below ~ 30-60 ° down. For the DXT-MON it is a bit more broadband, on the other side the KH-120A shows a longitudinal resonance of the BR channels (at 1,5kHz). I would be inclined to attach a little more importance to longitudinal resonance, it would anyway call it a draw .

Harmonic distortion (90dB / m & 100dB / m)



DXT-MON has slightly higher 2. order distortions below 400z, on the other side, in the same area, (at 90dB / m significantly) lower 3. Order distortions. 4. Order distortions are almost equal between both. DXT-MON is less impressed by the volume change between 90 and 100dB / m. This, along with the lower 3. order distortions, makes the DXT-MON the tight but deserved winner in this discipline. + 0,5 points for DXT-MON

Passive membrane vs. BR channels in front

dxt_mon_kh120_nahfeld_vglThe developers of the KH-120A succeeded in avoiding the usual problems of BR channels attached to the front as far as possible. This was achieved, among other things, by making slits with foam in the channels, whereby dirt effects are "smeared", and for this purpose, the tuning frequency was equalized. Nevertheless, the longitudinal resonator still beats around 1,5kHz with ~ -16dB, which is particularly evident in the measurements, e.g. towards the table top, shows. The bass reflex channels also contribute up to over 300Hz to the overall event.

In return, the passive membrane on the DXT-MON works as it should. No disruptive resonances, no mid-range components, from 300Hz at the latest the TMT works practically alone, and no equalization, which has a negative effect on the group delay, was necessary to achieve the desired depth ... + 1 point for DXT_MON

Adaptability / Flexibility

With the KH120A, this allows ...

kh120_a_maeuseklaviaturmake the following settings:

kh120a_filterSource: http://www.neumann-kh-line.com/neumann-kh/home_de.nsf/root/prof-monitoring_studio-monitors_nearfield-monitors_KH120A#

For this purpose, a limiter can be set. This works extremely practical, fast and reliable. Very good!

With the DXT-MON, a Hypex AS 2.100D with integrated DSP ...

AS 2.100DSource: https://www.hypexshop.com/ProdImgServlet?productID=2961

... practically everything can be adjusted. For standard corrections, such as the 4-stage acoustic control for bass, low-mid and treble of the KH-120A, no measurement technology is required.

AS_2_100_filter designer

Neumann KH-120A: Easier and faster with, usually sufficient possibilities

DXT-MON: Significantly extended possibilities with more complex operation

⇒We call it draw.


Neumann KH-120A DXT-MON
Kit including tree cap: ~ 265 € / piece
Hypex AS 2.100D: ~ 250 €
1300 € / pair ~780 € plus housing / pair



There is not much between DXT-MON and the Neumann KH-120A. Both measure themselves exceptionally well in practically every respect, taking into account given physical limits. Nevertheless, I could not help but to come to the following conclusion:

The passive diaphragm, and the outstandingly good WF152BD06 are, in the author's point of view, the tip of the scales towards a tight but deserved victory on points for DXT-MON.

... please write me your opinion in the comments 😉








Test Scan-Speak Discovery D2604 / 830000 with WG PCT-300 / WG-300 26mm dome tweeter 4 Ω with waveguide

Datasheet © www.heissmann-acoustics.de
Measurements in 20x40cm baffle, 10mm rounded, in 70cm distance at 2,83V. Level scaled to 1m.

The Waveguide was milled with a CNC adapter plate  mounted on the tweeter.

Scan-Speak D2604 / 830000 WG

Directivity horizontal (0°, 15°, 30°, 45°, 60° & 90°) & Impedance


... normalized to 0° (sonogram)


Due to the waveguide system-related symmetrical peak from 1-10kHz.
Extremely uniform directivity without significant disturbances. In the main very close to "Constant Directivity". The slight widening around 2,5kHz can be equalized by skillful choice of the midrange and its filtering.

Burst decay


Overall, very smooth and rapid decaying over all frequencies.

Minimal delayed in the super high tones.

harmonic distortions (90-105dB / m)


K3 remains, even at 105dB / m> 1kHz in the range

K2 rises evenly with increasing level and does not exceed the 1% mark by> 1kHz until levels> 100dB.



Frequency response / directional behavior:4.6 5 out of stars
Range:5 5 out of stars
Power handling:5 5 out of stars
consisty / without rating:0 5 out of stars
Haptics:4.5 5 out of stars
Price-performance:5 5 out of stars


The Scan-Speak D2604 / 830000 measures itself at the Waveguide, apart from the ~ 1dB lower efficiency practically identical to the D2604 / 833000. Hence the same conclusion:

In terms of "dome tweeter with waveguide" remain, realistically, nothing to be desired. Very broadband usable, extremely low-level distortions and in terms of directivity close to the ideal ...


Software supported crossover development ... or simulation vs. "Reality"


In this article, the working method, the wide-ranging possibilities and ultimately the reliability of software-supported crossover development are to be considered. It will exclusively the use of the computer as virtual crossover considered. No housing simulation, no frequency deviation simulation according to data sheets, TSP or any other parameters that are not based on real measurements on the object ⇒ All relevant data is obtained from real measurements!

The concrete approach in software-based crossover development is usually the following

  • Concept creation (driver / housing / baffle geometry) taking into account all possible factors, which will not be discussed here
  • Structure of the speaker: Case construction, absorption / insulation, cabling, bass tuning (BR / CB etc.) ⇒ Without crossover
  • Measurement of the individual, unfiltered drivers: Amplitude frequency response including relative acoustic phase under all desired angles and impedance response
  • Import of measurement data into the software, in this case Xover 2.04A

At this point a note: The measurement of a 2-way speaker under eg. 22 angles (+ -90 ° horizontal in 15 ° steps and + -20 ° vertical in 5 ° steps) including impedance measurements takes ~ 15 minutes

Let's imagine the following measurement setup

  • A cascade of "n" identical measurement microphones in a horizontal and vertical plane around the loudspeaker, which do not influence each other
  • A measuring device for detecting the impedance paths of the individual drivers and the whole loudspeaker simultaneouslywithout affecting the results
  • Hardware that can process and output all measurement results in real time
  • Software that can process and output all measurement results in real time
  • All required components without deviating from the target value ... or Components that can be set to any value using a controller
  • A transparent translator that changes / adjusts parts on instructions 😉

Everything is not really feasible, but should illustrate what is possible if we collect all the data one after the other and then let the software work with it.

Here is an example of the course of a crossover development with Xover 2.04a

The program is on the pages of the interest group DIY Hifi (IGDH eV) as Download is available for storage, management and analysis.

Top left: 0-90 ° Horizontal, sum / branches and phase
Top right: 0 ° and + -15 ° vertical, sum / branches and phase
Middle bottom: Impedazgänge branches and total
Bottom right: Voltage frequency response
Quiz question: What's going on at 1kHz? Use the comment function :)

We have a virtual crossover board on the screen, and see the effects of every component change on the amplitude frequency response (horizontal and vertical), phase, impedance response & voltage frequency response in real time. We can simultaneously Things that the on-foot developer thinks if any, only one after the other.

"On foot" is usually there. a Microphone, Impedance measuring stripe and a Component that is changed. Then you can Zweig or the sums, or look at the impedance frequency response. Everything under one Corner. The effects of a component change can basically only one aspect to be viewed as. The effects on other aspects must be "guessed" ...

If I change the slope of the tweeter in favor of a better phase angle, how does this affect the radiation behavior horizontally and - or vertically?

Of course, even very good speakers can be created. Direct-HA is the last loudspeaker that I developed ... The results are very good, but it took hours to do things that now take minutes or seconds. In the meantime I consider it very questionable whether the last bit of detail can really be achieved in a walking development.

The question of accuracy still arises ...

In order not to anticipate it quite unprovocatively: The virtual one - is more precise than the real development switch 😉 ...

We have real measured values ​​of the drivers (amplitude frequency response including rel. Phase and impedance response) and put them in a (virtual) AC circuit with frequency-dependent (L / C) and frequency-independent (R) impedances. The mode of action of capacitors, coils and resistors can be detected by formula. There are no relevant unknowns.

In contrast to the “real” development switch, there are practically no sources of error. The components do not have any deviations, there are no increased contact resistances, no wiring errors, no component mix-ups, no cold soldering points.

So that Reality In the end, there are really only a few possibilities:

  • Measurement conditions have changed (measurement setup, temperature, ...)
  • Components deviate from the standard value
  • Errors in the construction (crossover, cabling, faulty components ...)

If we trust our measurements, we can look at differences between reality and simulation, the error on the real object. Often the simulation can help here as well. We carry out targeted changes as long as the results correspond to the error. So I have often found out which component differs from the norm, where a contact resistance is too large, or where two components were confused. It will not be published until the simulation and final measurements of the speaker are practically the same. The virtual crossover as a reliable fault diagnosis tool!

Here's an example of the match between simulation and measurement on the finished speaker:

In Jumping simulation and final measurements of a speaker at horizontal angles of 0-90 ° in 15 ° steps

It can be practically talked of congruence at all angles. The minimal deviations are due to slight deviations in the final measurement setup and possibly tolerances in the components.

The advantages of a software-supported crossover development summarized once again

  • Time
  • Material: No cabinet with components needed.
  • More efficient crossovers: Both “on foot” and in the simulation, a “filter finding” takes place as follows, for example: You start with a, say, 2nd order high-pass filter and a voltage divider. Then there is an increase in the air, which is then ironed out with a blocking or suction circuit. As soon as everything looks good you are finished "on foot". In the simulation you can now try to find a filter function that delivers an identical result with fewer and / or cheaper components ... often works!
  • The simulation as an error diagnosis tool. If the simulation and the final measurements agree, it can be assumed with a probability bordering on certainty that the structure is error-free. Very good in terms of "replica security"
  • Steep learning curve when it comes to filter design, even with experienced developers ...
  • Variability: Variations of a loudspeaker can also be created in retrospect because a complete and verified simulation model exists.
  • "Trial & error switch" until it fits => pre-defined acoustic filter edges
  • The cascade of "n" identical measurement microphones ⇒ an extremely practical way to "controlled directivity" loudspeakers

In conclusion:

The art of developing a good loudspeaker should not primarily lie in the crossover design, but rather in finding an overall concept that is coherent for the intended work area. Find very good drivers and define a meaningful work area. A good housing design (inside and outside) and the baffle geometry that is so often ignored. How the drivers ultimately want to be filtered is, in my opinion, largely predetermined by the overall concept. Theoretically, we could leave the development of the crossover completely to the computer ... A good crossover optimizer, fed with 360 ° measurements horizontally, vertically and diagonally, to which we make specifications regarding the energy behavior of the loudspeaker and the area of ​​application of the drivers, will find better / more effective crossovers than we can . An exception is of course "the first litter of the experienced developer" 😉

Diagonal chamfers ... effect, steepness and positioning

The topic of baffle geometry and its influence on the playback quality of loudspeakers has already been discussed in the article "About baffle design, edge diffraction, secondary sound sources, ...“Received in detail. If you still believe in the design of a baffle and the arrangement of the drivers on the same is primarily a question of optics, please read the article (again).

In the process of finding a suitable baffle, I often ended up with the variant "sloping bevels". The question arose again and again how steep these really have to be in order to be effective. So far I have relied on secondary knowledge in this regard ... read in books, forums, magazines. When the question came up again recently, I decided to investigate the matter with measurements.

To accomplish this, a baffle with adjustable, beveled chamfers had to be made. After a lot of headache, how to build this, I finally came to the following conclusion:

schraege_fase_variabelA V-groove was milled from behind, slightly less deep than the plate thickness, the whole thing "secured" from the front with adhesive tape and a 2mm thick copper wire stapled from above, which serves as an adjustment mechanism. The "wings" can be set anywhere from 0 ° -55 °.


For the tweeter, I chose one that by itself does not show any disturbances in the directional behavior in the area relevant for edge diffraction, which could falsify the results. The choice was much to the one I really appreciate XT25TG-30 / 04.

In 55 ° steps for chamfer angles of o-5 °, the respective radiation behavior of 0-90 ° in 10 ° steps was measured. Altogether 120 measurements.

The initial situation: Bevel angle 0 °

See also "Worst case" scenario

The left picture shows the radiation behavior in a sonogram normalized to 0 °. The right-hand example shows the angles 0, 30 and 60 °.

The sonogram shows that the loudspeaker is considerably too wide around 3kHz and radiates too narrow below that. Axis and angular frequency responses are unbalanced to one another. Where there is a depression on the axis, there is a superelevation at angles. The loudspeaker changes its character with the listening position. A steady and as evenly narrower course as possible would be desirable.

Measurement results

Sonogram for chamfers with a slope of 0-55 ° in 5 ° steps


0,30 and 60 ° for bevel angles of 0-50 ° in 10 ° steps


The main disturbance (expansion by 3kHz associated with the constriction below) decreases with a larger bevel angle. Chamfers with a slope of <20 ° do not yet produce satisfactory results.

The chamfers themselves form a new edge, which comes to bear with increasing steepness. Recognizable by the arising expansion around 5Khz. This is less pronounced because the tweeter in this area is no longer working as a half-space radiator.

In addition to resolving the "rectangular geometry", this is one of the main tasks of the inclined bevel: bringing the housing edges so close to the tweeter that it no longer "sees" you or only weakly. Shorter distance ⇒ shorter wavelength higher frequency ⇒ more directivity ⇒ less influence of the edge

The “inclined bevel” concept works particularly well when the tweeter is already clearly bundling in the corresponding frequency band and thus it is practically no longer “seen” at all. Of the Seas DXT 27TBCD / GB be mentioned here by way of example. How well this driver works with oblique chamfers is an example DXT-Mon to see.

In summary:

  • Chamfers <20 ° are not sufficiently effective
  • The distance of the chamfers to the place of sound creation must be sufficiently low, otherwise one reaches only one, at least partial, displacement of the problem
  • Depending on the situation, the chamfers can also zu steep be!

The concept of the bevel chamfers doesn't really work around the problem to get over. But not unconditionally. The slope and position must be chosen carefully and according to the concept. If you were to ask me for a universal recommendation, I would say:

"Make the bevels 25-35 ° steep and position them as close to the tweeter as possible"

Finally, the measurements in single images, for those who want to take a closer look. The steepness of the chamfer is in the lower left corner of the picture.

Note: The picture change is also possible with the mouse wheel







Test Scan-Speak Discovery D2604 / 833000 with WG PCT-300 / WG-300 26mm dome tweeter 4 Ω with waveguide

Datasheet © www.heissmann-acoustics.de
Measurements in 20x40cm baffle, 10mm rounded, in 70cm distance at 2,83V. Level scaled to 1m.

The Waveguide was milled with a CNC adapter plate  mounted on the tweeter.


Directivity horizontal (0°, 15°, 30°, 45°, 60° & 90°) & Impedance


... normalized to 0° (sonogram)


Due to the waveguide, system-induced symmetrical peak from 1-10kHz.
Extremely uniform directivity without significant interference. In the main very close to "Constant Directivity". The slight widening around 2,5kHz can be equalized by skillful choice of the midrange and its filtering.

Burst decay


Overall, very smooth and rapid decaying over all frequencies.

Minimal delay in the super high frequency> 15kHz.

harmonic distortions (90-105dB / m)


K3 remains at <xnumx% at="" all="" measured="" levels,="" even="" xnumxdb="" m=""> 105kHz, and is largely independent of the excitation signal.</xnumx%>

K2 rising evenly with increasing level and exceeds the 1% mark appreciably only at levels> 100dB.



Frequency response / directional behavior:4.8 5 out of stars
Range:5 5 out of stars
Power handling:5 5 out of stars
consisty / without rating:0 5 out of stars
Haptics:4.5 5 out of stars
Price-performance:5 5 out of stars


The reader may have noticed one or the other similarity to the Peerless DX25TG09-04 (Vifa XD-270 F/4) with Waveguide ...

The Scan-Speak is practically equivalent in all respects. It measures on axis a touch more restless, can play minimal louder, could probably be crossed slightly deeper, .
In terms of "dome tweeter with waveguide" remain, realistically, nothing to be desired. Very broadband usable, extremely low-level distortions and in terms of directivity close to the ideal ...


Center HQ & Compact HQ center/rear for Samuel HQ, universal speaker


Technical data

  • Impedance: 6 Ohm
  • Sensitivity (2,83V/1m): 84 dB
  • HxWxD (mm): 204 + 69x 356x321
  • Crossover frequency: 1900 Hz
  • Frequency range (-8 / -3dB): 48/69 -> 30000 Hz
  • Concept: closed box, 15l


  • Home Theater:
    • Center
    • Hair
    • Rear
  • Audiophile stereo applications


  • flat frequency response
  • very uniform dispersion, both horizontally and vertically
  • from 200Hz very gently sloping bass close to the wall possible
  • standing and lying operable


Peerless XT25SC90-04 (Vifa XT-25 / Neo4)

Test at Heißmann-Acoustics.de

Monacor SPH-175HQ

Sound and sound 06 / 2012

The SPH-175HQ passed our test course with bravura... Very high-quality driver, which cuts a good figure both in two-way constructions and as a low-frequency specialist


building plan

Test Scan-Speak Discovery D2604 / 833000 26mm dome tweeter 4 Ω

Datasheet © www.heissmann-acoustics.de
Measurements in DIN baffle in 70cm distance at 2,83V. Level scaled to 1m.

Scan-Speak Discovery D2604 / 833000

Frequency response and impedance (consisty)

Scan-Speak D2604 / 833000 frequency response

Extremely broadband frequency response. Full level from 1,1kHz, with good linearity.

The average efficiency is exceptionally at 93dB / 2,83V.

Impedance is flawless. The resonant frequency with 430 respectively 440Hz is below the manufacturer's specification of 475Hz.

Both drivers behave almost congruently both in amplitude and impedance.

 Directivity horizontal (0°, 15°, 30°, 45°, 60°)

Scan-Speak Discovery D2604 / 833000 directivity

Directivity of the Scan-Speak D2604 / 833000 is even and balanced throughout the entire transmission range.

In the top octaves> 10kHz significantly wider radiating than, due to the effective membrane area of ​​8cm², would be expected.

Burst decay

Scan-Speak Discovery D2604 / 833000 burst decay

Overall smooth and fast decay over all frequencies.

> 10kHz minimal delay.

harmonic distortions

Scan-Speak Discovery D2604 / 833000 distortions

The Scan-Speak D2604 / 833000 has outstanding low harmonic distortions.

K3 remains below 1% at all measured levels> 0,5kHz largely independent of the excitation signal.

K2 increases with the level, extends very evenly and would not reach the 1% to 1dB / m even with a crossover-point at 100kHz!


Frequency response / directional behavior:4.5 5 out of stars
Range:5 5 out of stars
Power handling:4.7 5 out of stars
consisty / without rating:0 5 out of stars
Haptics:4.5 5 out of stars
Price-performance:4.7 5 out of stars


With an effective membrane area of ​​8cm², a resonant frequency <xnumxhz and="" the="" very="" low="" harmonic="" distortions,="" driver="" invites="" to="" be="" deeply="" crossed="" eg.="" a="" xnumxer="" mid-woofer.="" crossover="" frequencies=""> = 500kHz should be possible without any problems. In smaller systems, eg with a 20er TMT, the Scan-Speak D1,5 / 13 could be crossed even at lower frequencies.</xnumxhz>

The concept of a large effective membrane area, in combination with a "standard voice coil" (26mm), and a rather soft dome material works out. Widely radiating in te top octaves, crossable very low, with high load capacity.

=> Scan-Speak D2604 / 833000 with waveguide




  • exceptionally pure and neutral sound
  • superbly uniform directivity
  • outstanding impulse response and resolution
  • lowest harmonic and non-linear distortions

Technical data

  • Nominal impedance: 4 Ohm
  • Crossover frequency: 1800Hz LR4
  • Sensitivity (2,83V/1m): 83 dB
  • Principle: 2 ways, bass reflex / passive membrane
  • Dimensions (HxWxD):
    • Version PM 8l: 308 x 204 x 244mm
    • Version PM 9,5l: 330 x 204 x 258mm
  • Net volume: 8l or 9,5l
  • Frequency range (-3dB):
    • Version PM 8l: 54 - 40000 Hz
    • Version PM 9,5l: 50 - 40000 Hz


  • Near field monitoring
  • High-end desktop speakers
  • High-quality stereo aplications in small to medium sized rooms
  • Home theater: Main / Center / Rear with subwoofer support


Wavecor WF152BD06

Klang & Ton 02 / 2013

In this as in all other respects, the new driver is perfect: even at 95 decibel the driver has almost no distortions, has almost no resonance up to almost 10 kilohertz and shows a perfectly balanced frequency response ... The processing is Waveor-typical excellent - they only have the best materials installed.

Seas DXT 27TBCD / GB (H1499): Test



16mm MDF, with inside alubutyl (double). The front has a thickness of 38mm. This is eg. achieved by gluing two 19mm plates.



Cost example (ehighend.de Stand 05 / 2017)

Buy cabinet kits

Modification of the Monacor DT-300 tweeter, according to Klang & Ton 6/14

A customer request, whether in the sound and sound 06 / 14 (kit MonaLisa, developer Ronald Waßen) presented modification of the tweeter DT-300 synonymous in the Cinetor meaningful, I took the opportunity to perform this.


In the modification, the ferrofluid is removed, introduced into the Polkernbohrung insulation wool and glued a felt ring on the pole plate. A detailed guide can be found in the Sound and sound forum.

The metrological results

All measurements were made with Waveguide, in 20cm narrow baffle.

frequency response

DT300_klang_und_ton_mod_ampSignificantly extended frequency response towards lower frequencies. Minimal higher efficiency, otherwise practically congruent course.

impedance response

DT300_klang_und_ton_mod_impSignificant influence of the modification on the impedance response. Clean and symmetrical impedance peak at 800Hz (blue). Compared to before (black), with a clearly flattened course and 3 impedance bumps (some DT-300 only show one double bump). In order to achieve a really clean and symmetrical impedance peak after the ferrofluid has been removed, the pole core hole must be tightly stuffed with insulating wool. The pole core hole was effectively closed acoustically by a 14x3cm long strip (blue). Compared to this (red) a little less stuffed, with a 7x3cm strip. The "new" impedance response allows significantly deeper separations, so the distortion measurements should not prevent this ...

Harmonic distortions

DT300_klang_und_ton_mod_dist... and you don't. No increased harmonic distortion. K2 between 800Hz and 2kHz is even slightly lower. Separations around 1,5kHz, possibly even deeper, should now be feasible!


Burst decay

DT300_klang_und_ton_mod_bdSlightly improved decay behavior around 7, - and 13kHz.




Meaningfulness of the modification of existing systems

DT300_klang_und_ton_mod_weicheThe example shows a separation of 2kHz with 18dB / oct. Dashed without, solid with modification. The frequency response in the working range shows slight deviations, but the slope changes towards the mid-bass, which can have a negative effect on the overall system. It is therefore not possible at this point to give a blanket "approval" for the modification of existing systems.

And finally ...

The modified DT-300 is the better DT-300. Significantly more beautiful impedance, more separable, more even decay, and minimally balanced in super high tone. Negative effects could not be determined.


The modification should not be done without control measurements. A simple impedance measurement, which can be realized with the free version of LIMP (part of the ARTA Family) and a material usage of 1-2 €, is completely sufficient.


It should be ensured that the voice coil is still well centered after the modification. There are a few factors that influence it.

  • She was not there before
  • The tightening torque of the screws
  • Possible game in the forced centering
  • The positive centering allows two mounting positions, which can lead to different results

Ferrofluid can compensate for small errors in the centering of the voice coil. It could happen that one, just before the modification just enough central voice coil, grinds or hangs after the mod at the air gap.

About baffle design, edge diffraction, secondary sound sources, ... ... and their influence on the sound quality of loudspeakers

KantendiffraktionIt is to be examined how the design of the baffle and the arrangement of the drivers, affect the reproduction quality of loudspeakers. In particular, the attention is paid to the directional behavior, of the tweeter. In addition to the frequency response on axis (0 °), a balanced and uniform directional behavior has a considerable, and in the author's perception sometimes (too) neglected, influence on the playback quality, also and especially in terms of spatial representation of the sound, of speakers.

Imbalances between on-axis, and off-axis frequency responses very often result from an inappropriate baffle design including missplacement of the drivers. The tweeter "sees" the baffle edges in the intended frequency range, where secondary sound sources are created.

Those who value a loudspeaker not only by its tone, but also by a good stage presentation, should take a trained look at the baffle of the speaker in addition to reading impressive sound descriptions. To train this view is the concern of this article ...

In the following, the directional behavior of 25mm tweeters in different installation situations is examined. The influence of midrange speakers is usually less problematic and should not be considered here.

The first four examples are based on (reliable) simulations, assuming a tweeter linearized on the axis and separated at 2kHz. The simulations and measurements show the angles 0,30 & 60 ° horizontally.

First, two installation situations without or with only minimal influence on the housing:

The infinite baffle

Uniform, flawless directional behavior, starting from the frequency given by the tweeter surface of the tweeter. No edge diffraction and / or secondary sound sources.

Tweeter with very small front panel, without baffle

The "housing edges", in this case the edges of the tweeter itself, are so close that the associated frequency is in a range in which the tweeter no longer works as a half-space radiator. He practically does not "see" them. The system can be viewed as a system without a baffle.

Uniform, impeccable directional behavior without problems due to edge diffraction.

The non-existent baffle also stabilizes the directional behavior towards the woofer, even below the frequency specified by the membrane surface of the tweeter. Ideal conditions for a seamless connection to the directional behavior of the woofer.

This concept is used in the Kit Center-HQ.

"Worst case" scenario

... in the author's point of view

Baffle rectangular, narrow, tweeter in the middle, no waveguide, no chamfers

The tweeter "sees" the baffle edges in the intended working area. => Edge diffraction. The result is an on-axis dip with a peak at angles. In the simulation, the tweeter is linearized, => the dip on the axis has been compensated, which makes the peaks at angles more revealing accordingly. Regardless of how the driver filtered to the axis, the discrepancy between on-axis and off-axis frequency responses remains.

Follow us:

Tonality: Imbalance under different listening positions.

space: The space suffers from the imbalance of axis and angular frequency responses

Usually such concepts are coordinated with a sink on the axis, which is then "filled up" again at angles. In terms of tonality, that can sound very good. In an area that is sensitive to the ear there is a depression (I like to call this "ear flatterer"), but nothing is missing energetically, as it is compensated at angles.

A second approach would be to separate very high (in this case> 3,5kHz). However, this causes other problems. The mid-bass driver already directs clearly in this area and is then "replaced" by the tweeter, which still works as a half-space radiator => The energy frequency response is unbalanced. In the area of ​​the crossover frequency, too little and too much energy is released into the room. Furthermore, it becomes more and more unbalanced in the vertical direction as the crossover frequency increases. The distance between the drivers must always be seen in relation to the crossover frequency.

This concept finds application in very many, vA speakers developed under time, and or selling pressure 😉

... with 15mm bevels

Baffle rectangular, narrow, tweeter centered, 15mm bevels on both sides

The chamfers weaken the interference, but the fundamental problem persists. The above written remains valid.

How to deal with the problem?

In addition to the infinite baffle and the "practically non-existent" one, there are other, promising approaches to avoid or significantly reduce edge diffraction.

The following examples are all based on real measurements from speakers I have published. There is no claim to completeness.

Wide baffle with generous rounding on the sides

In this case there is no 60 ° measurement, so 0,30 & 45 ° are shown.

No edge diffraction in the intended work area. The (rounded) edges are far enough away that they cannot be "seen". Extremely even straightening behavior.

This concept was used in the construction proposal Wave Wall 182, Another very appealing speaker that follows a similar approach is eg. the Grimm LS1.

Tweeter positioned off-center with 12mm chamfer sideways and up

Low influence by edge diffraction at 2,2kHz, which can be easily compensated for by a suitable filter from the midrange driver. In addition, uniform and trouble-free omnidirectional behavior.

This concept was used in the construction proposal Samuel HQ

Trapezoidal chamfers with a steepness> = 20 °, brought as close as possible to the tweeter

Slight expansion around 5kHz, otherwise no problems due to edge diffraction. The bundling behavior is, characterized in that the tweeter sees only very little baffle, to the directional behavior of the mid-bass, which allows a seamless connection to this only.

The upper chamfer is, depending on the concept, not necessarily needed. Under certain circumstances, the result could even be (even) better without this.

This concept is used, for example, in the building proposals Samira & Samira-HWG.

Tweeter with sound guide / waveguide and maximum narrow baffle

No edge diffraction at all. Extremely even directional behavior in the entire transmission range. In contrast to normal dome tweeters, even in the super high range (> 10kHz) wide and even radiation Concerning. horizontal bundling an almost perfect solution.

However, the distance to the mid-bass driver is greater than without sound conduction, which adversely affects the vertical radiation behavior. This problem is avoided by a correspondingly deeper separation, which, thanks to the sound pressure increasing and thus driver-relieving effect of the waveguide usually. is also feasible.

This concept is used in the building proposals Cinetor & Cinetor-HWG

Sound guide (DXT) & trapezoidal chamfers

The same applies as in the previous example, but without the problem of the large driver gap. The tweeter used here is the Seas-DXT. The size of a "normal" tweeter (D104mm), with the effect of a real waveguide. Fascinating!

The trapezoidal phases do the rest, especially in terms of stabilization of the bundling behavior towards the mid-bass driver. In wider baffles there would be a widening in the transmission range, usually. to 3kHz which would be compensated only by a correspondingly high crossover frequency.

The horizontal straightening comes very close to the theoretical ideal perceived by the author!

This concept was used in the construction proposal DXT-Mon

And finally ...

There are very meaningful and simple approaches to tackle the topic of edge diffraction in tweeters:

  • Give it a lot of baffle: The case edges are far enough away so that the tweeter will not see you in the intended work area
  • Unsymmetry: If possible, no identical distances between the edges and the tweeter. This can be achieved by the position of the driver (off-center) and / or the design of the baffle. As an example, the Rocket of Hifi DIY it was already mentioned.
  • ... accompanied by as little baffle as possible => the directional behavior is steadied towards the bass-midrange driver, which can make the seamless connection to the bass-midrange driver considerably easier (=> e.g. trapezoidal chamfers).
  • Use of sound guides (waveguides, horns) which have a clear directivity in the, for edge diffraction relevant frequency range. Usually. Waveguide solutions should aim for a maximally narrow baffle in order to stabilize its emission towards the mid-bass driver.

... there is actually only one problematic case

  • A rectangular baffle, approx. The width of the bass-midrange speaker, with a central tweeter and without sound guide ...

In my experience, uniform and largely unbroken bundling behavior is one of the most important, if not the least The most important quality feature of a good speaker.

With this article, the dear reader has (hopefully) learned to be able to judge this, at least partially, by looking at a loudspeaker. Nevertheless, being able to read a little measurements is definitely helpful ...


It is not sensible to provide existing loudspeakers with chamfers, new baffles, sound guides and / or driver arrangements. In the vast majority of cases, this requires a metrological check and a corresponding adaptation of the crossover.

For questions, suggestions & criticism: feel invited to use the comment function!



Test Seas DXT 27TBCD / GB (H1499-06) 25mm dome with waveguide, 6 Ω

Datasheet © www.heissmann-acoustics.de
Measurements in DIN baffle in 70cm distance at 2,83V. Level scaled to 1m



Seas DXT 27TBCD / GB sound pressure & impedance (dispersion)


Very broadband and symmetrical superelevation from 800Hz to 10kHz, which can be easily equalized with the crossover. This is due to the waveguide and already a first indication of its effectiveness.

The efficiency reaches broadband 95dB but then drops down to 88dB in super high. In the case of linear tuning, therefore, no more than the named 88dB / 2,83V / m are achieved.

The impedance response is interference-free and shows a slightly asymmetrical "resonance hill" around 900Hz. More often seen in tweeters with coupling volume.

 Seas DXT 27TBCD / GB Sound pressure at angles (15 °, 30 °, 45 °, 60 °)


Extremely even directivity into the super high tone. In large parts near the so-called constant directivity Behavior.

Seas DXT 27TBCD / GB Decay behavior


Even and fast decay over all frequencies.

 Seas DXT 27TBCD / GB level linearity 85, 90, 95 and 100dB


Frequency response level corrected, based on the 85dB measurement

Even and low dynamic compression from 100dB / m <= 0,5dB (Please note the scaling => 20dB range)

Seas DXT 27TBCD / GB harmonic distortion


Extremely low harmonic distortion even at 100dB. K2 increases evenly with the level and remains below the 100% mark until 2dB starting at 1kHz.

K3 increasing below 2,5kHz, above that at the measurability limit.


Frequency response / directional behavior:5 5 out of stars
Range:4.5 5 out of stars
Power handling:4.5 5 out of stars
Consisty:4.5 5 out of stars
Haptics:4.5 5 out of stars
Price-performance:4.8 5 out of stars


Nowadays the straightening behavior of loudspeakers is getting more and more important. The Seas DXT stands out in this discipline from the competition. No other known tweeter of this size shows as uniform straightening as the Seas DXT.

However, a careful baffle design is required to maintain this behavior. In "normal widths" baffles (~ 20cm) for example. the Seas DXT tends to widen significantly at angles around 3kHz.

Work very well:

  • a practically nonexistent ...
  • or a very wide baffle.

See also here

Also in all other disciplines of the Seas DXT shows without blemish and blame.


Test Wavecor TW030WA09 30mm dome tweeter with low sound conduction 4Ω

Datasheet © www.heissmann-acoustics.de
Measurements in DIN baffle in 70cm distance at 2,83V. Level scaled to 1m

Wavecor TW030WA09

Wavecor TW030WA09 frequency response & impedance (consisty)


Very good linearity with evenly decreasing amplitude response. Extremely broadband. The efficiency is on average around 93dB / 2,83V. In the super highs, however, only to 88-90dB.

Both drivers are practically congruent in their frequency response up to 10kHz. Above very small deviations. Very good. The TW030WA09 is expressly advertised as "... best consistency" in the manufacturer data sheet.

There are no disturbances in the impedance. Practically congruent graph of both drivers. Exemplary.

The resonance frequency is at 700Hz. Very low for a driver without coupling volume. The accented resonance peak indicates that there should no ferrofluid be found in the air gap.

 Wavecor TW030WA09 sound pressure at angles (15 °, 30 °, 45 °, 60 °)


Very even and balanced omnidirectional behavior. For a tweeter equipped with a 30mm voice coil even in the super high tones still widely radiating.

Wavecor TW030WA09 decay behavior


Very even and fast decay over all frequencies.

Wavecor TW030WA09 level linearity 85, 90, 95 and 100dB

Frequency response level corrected, based on the 85dB measurement

From 100dB minimum dynamic compression <= 0,5dB in the super high tone.

(Please note the scaling => 20dB range)

Wavecor TW030WA09 harmonic distortion


Very low harmonic distortion even with 100dB. K2 increases evenly with the level, hardly exceeding the 100% mark even with the 1dB measurement.

K3 and higher-order distortions play virtually no role. One might be tempted to separate the tweeter with a steep edge at 1200Hz. Who wants to be safe takes 1,5kHz.


Frequency response / directional behavior:4.5 5 out of stars
Range:4.8 5 out of stars
Power handling:4.5 5 out of stars
Consisty:4.5 5 out of stars
Haptics:4.8 5 out of stars
Price-performance:4.5 5 out of stars


The Wavecor TW030WA09 ...

with its 30mm voice coil, a resonant frequency around 700Hz and the very low harmonic distortion already from 1kHz invites you to be married to a beautiful 20 midrange driver. Messtechnisch he makes no weaknesses, is very deep, looks classy, ​​and is, with an EIA of only €55 (As of Dec. 2013) to be described as extremely cheap.


Test Seas Noferro-900 Visaton Waveguide WG-148R 4 Ω dome tweeter with Visaton waveguide

Datasheet © www.heissmann-acoustics.de
Measurements in 17x35cm baffle in 70cm distance at 2,83V. level scaled to 1m

Seas Noferro-900 Visaton Waveguide WG-148R

4 Ω dome tweeter with waveguide

Noferro900_W148R_2     Noferro900_W148R_1

With the new WG148R Visaton has placed an excellently processed waveguide for 25 mm tweeters on the market. This was combined with the Seas Noferro-900, with excellent results.

To mount the Seas Noferro-900 to the WG148R you only have to widen the screw holes of the tweeter from 4,5 to approx. 6mm.

Directivity horizontal (0-90 ° in 15 ° steps)


Due to the waveguide system-related symmetrical elevation in the frequency range from 1-10kHz.

The Seas Noferro 900 and the Waveguide WG-148R are a perfect match. Both mechanically and, and in particular acoustically. Directivity is extremly even, up to highest octaves. Just above 3kHz there is a slight widening. This can be further improved by clever connection to an 5-7 inch mid-bass driver. That behavior fitted perfectly with midrange speakers of the 15cm class. Crossover points around 2-3kHz promise excellent results.

It should be noted: The combination was measured in a maximum narrow baffle (17cm). Such is usually very beneficial for waveguides in terms of controlled directivity.

In the 2. Image, frequency response was roughly linearized by DSP. A shelving filter and a PEQ were set.

Sound pressure standardized at angles to 15 °




Flawless impedance.

Very accented, resonance peak at 900Hz, labeling the tweeter as ferrofluid-free.

Burst decay


Even and rapid decay over all frequencies. Perfectly.

Harmonic Distortions 85, 90 and 95dB


The harmonic distortions are extremely low. Only at 10kHz scratched K2 at 95dB / m at the 1% mark ... inaudible. K3 and higher orders are negligible. Crossovers around 1,5kHz with> = 18dB / Oct can be realized without any problems.


Frequency response / directional behavior:5 5 out of stars
Range:5 5 out of stars
Power handling:4.5 5 out of stars
Constance / Without Rating /:0 5 out of stars
Haptics:4.5 5 out of stars
Price-performance:5 5 out of stars


The Seas Noferro-XNUMX with the Visaton Waveguide WG-XNUMXR measures itself ...

... excellent in all disciplines! There is not much more to say about it.

The sum of the EIAs is incidentally, in view of the results, hard to believeXNUMX € (WGXNUMXR: XNUMX € and NoferroXNUMX XNUMX €, as of October XNUMX).


WaveWall-182 | On-wall | a high quality on-wall speaker


"Form follows function"

With these words, the development of WaveWall 182 is probably best paraphrased.

The generous curves flowing into the wall, along with the very small case depth, allow the excellent acoustic characteristics of the WaveWall-182.
The speakers not only fuses optically, but also acoustically with the wall.

The on-wall installation offers concrete advantages compared to conventional loudspeakers:

  • a significant gain in efficiency
  • correspondingly higher maximum level
  • lower distortions
  • smoother dispersion
  • inconspicuous integration into the living space
  • ... along with a maximum WAF


The usual problems with conventional on-wall solutions have been successfully bypassed, in particular by the complex housing design. The dispersion is extremely uniform and without disturbances due to diffraktion, which, in particular, greatly benefits the three-dimensional representation of the sound event. Even in the vertical, the WaveWall 182 measures itself very well. It does not necessarily require an alignment to ear height. Burst-decay is flawless.

Particularly noteworthy are the outstanding low harmonic distortions, especially in the for the ear very critical midrange. Even with 100dB / m they remain in the range of inaudibility. That shows clearly how much know-how has gone into the development of the drivers.

Technical data:

  • Nominal impedance: 4 Ohm
  • Crossover frequency 1800Hz
  • Sensitivity (2,83V/1m): 85 dB
  • Dimensions (HxWxD): 450 x 576 / 366 (Rear / Front) x 102 mm
  • Frequency range (-8dB): 37 - 30000 Hz
  • Consept: closed box


  • Audiophile living room with maximum WAF
  • Center / Main / Rear in home theater
  • Center behind acoustically transparent canvas
  • Sound system in bars, pubs & cafes



  • Wavecor WF182BD10
Hobby Hifi 03 / 2014

These drivers (Note: WF182BD09 and WF182BD10) offer outstanding value for money. For audiophile and living room-friendly two-way floor boxes, they are simply perfect.

  • Wavecor TW030WA09
Heißmann-Acoustics Test
Hobby-Hifi 06 / 2013

Wavecor manages with the TW030WA09 to exceed the already excellent 30-millimeter tweeters of the house. The moderate price of the tweeter is not meant to deceive that it is an excellent tweeter with high-end demand and terrific value for money.



Buy cabinet kits


Test Scan-Speak D3004-660000 Illuminator

Datasheet © www.heissmann-acoustics.de
Measurements in DIN baffle in 70cm distance at 2,83V. Level scaled to 1m

Scan-Speak D3004 / 660000 Illuminator

4 Ohm dome tweeter with neodymium drive (Air-Circ magnet system)Scan_Speak_D3004_660000

Scan-Speak D3004 / 660000 Illuminator Sound pressure at angles (0-60 ° in 15 ° steps)


The amplitude response of the Scan-Speak D3004 / 660000 Illuminator is extremely broadband. Full level already from 600 Hertz.

From 600Hz - 30kHz + -1,5dB linear with a broadband increase (+ 2dB) of 1,5kHz - 6kHz. The average efficiency is 92dB / 2,83V.

The omnidirectional behavior can be described as very good. Below 30 °, 20kHz is reached with practically full level. The resonance frequency is extremely low at 470Hz and gives hope for a very deep separability to the TMT / MT. The impedance response shows a minimal disturbance of around 1,5 kHz, which is also reflected in the amplitude response by a "level" that is considered harmless.

Scan-Speak D3004 / 660000 Illuminator Decay behavior


Fast and steady decay over all frequencies. A touch of delay indicates 19kHz.

Scan-Speak D3004 / 660000 Illuminator Harmonic Distortions

gray line: 1%
Graph switches every 3 seconds
The Scan-Speak D3004 / 660000 illuminator has extremely low harmonic distortion.

At all measured levels, K3 remains below 500% from 0,3 Hz and <1% from 0,1 kHz and is largely independent of the excitation signal.

K2 increases evenly with the level, and runs at a very low level.

Clinker components of higher order are negligible.


Frequency response / directional behavior:4.2 5 out of stars
Range:5 5 out of stars
Power handling:4.8 5 out of stars
Continuity of series / Without rating /:0 5 out of stars
Haptics:5 5 out of stars
Price-performance:4 5 out of stars


The Scan-Speak D3004 / 660000 Illuminator is, in the sum of its properties, an excellent tweeter. Very broadband use, extremely low distortion and with very good omnidirectional behavior.

There was a considerable design effort to create an extraordinary tweeter. The Air-Circ Magnet System (6 Circular Neodymium Magnets) seems to work very effectively.

Only the not absolutely linear amplitude response on the axis clouds the otherwise impeccable impression minimal. By skillful wiring and / or selection of the baffle can still achieve a virtually perfectly linear frequency response.

Also noteworthy is the noble-looking exterior of the tweeter. The aluminum front panel and the seemingly futuristic magnet system make your heart beat faster, and in the sense of psychoacoustics, the driver will probably (even) sound even better ())

In order to do justice to the called price of RRP 180 €, features are required that set the driver apart from others. In my opinion, these are definitely given with the Scan-Speak D3004 / 660000 Illuminator and the driver is probably his Price-worthy!

Test Peerless XT19TD00-04 (Vifa XT-200 K4) Ring radiator, 4 Ω

Datasheet © www.heissmann-acoustics.de
Measurements in DIN baffle in 70cm distance at 2,83V. Level scaled to 1m
Vifa Peerless XT200K4 XT19TD00-0419mm ring radiator from Peerless, distributed by Quint-Audio. Equipped with a 4mm front plate, a 4-hole attachment, a "bead only design" as a membrane, a coupling volume and excellent measured values ​​...

Vifa / Peerless XT19TD00-04 (XT-200 K4) sound pressure & impedance (dispersion)


Outstanding linear frequency response. From 2,5-14kHz + -0,5dB!

Full level from 1,2kHz. Extremely good-natured "roll-off". With an average of 89,5dB / 2,83V, the efficiency is rather below average. For most applications, however, completely sufficient.

Outstanding pair equality in the two measured copies both in impedance, - and amplitude response. The maximum deviation of both drivers> 500 Hertz is + -0,15dB! This testifies to an excellent production consistency.

Thanks coupling volume very low resonance frequency around 750Hz. The impedance peaks indicate a dose of low-viscosity ferrofluid. Their slightly different characteristics are completely meaningless, being far out of the usable range.

 Vifa / Peerless XT19TD00-04 (XT-200 K4) Sound pressure at angles (15 °, 30 °, 45 °, 60 °)

Vifa Peerless_XT19_XT200_angle

Extremely consistent and a 19mm voice coil corresponding Rundstrahlverhalten.Idealer game partner for broad-beam concepts. Also interesting would be the ring emitter a very small baffle (similar Samira) to provide a uniform directivity to the TMT / MT.

Vifa / Peerless XT19TD00-04 (XT-200 K4) Decay behavior

Vifa Peerless XT19_XT200 Lingering behavior

Very smooth and fast decay over all frequencies.

Vifa / Peerless XT19TD00-04 (XT-200 K4) harmonic distortion

Vifa Peerless_XT19_XT200_Circle
gray line: 1% distortion
Graph switches every 3 seconds
Outstanding low distortion 3.order. From 2kHz at all measured levels <0,1%. The "good-natured" K2 increases relatively sharply below 3kHz. A little bit of "enhancement" is built in. Higher order distortion components are practically not apparent. For very level-stable combinations, I recommend separations from 3kHz. Smaller 2-way (e.g. with a 4 ″ TMT) can be separated by 2kHz.


Frequency response / directional behavior:4.6 5 out of stars
Range:4 5 out of stars
Power handling:3.8 5 out of stars
Consisty:4.5 5 out of stars
Haptics:4.3 5 out of stars
Price-performance:5 5 out of stars


The 19mm ring emitter Vifa / Peerless XT19TD00-04 (XT-200 K4) measured in the sum of its properties absolutely outstanding!

The relationship to his big brother, the XT25TG30-04 shows not only on the outside but also in all measurements. (The resourceful reader will have noticed that a few passages in the text are identical in both tests ...)

The frequency response is linearly smooth. Can be used in very level-stable combinations from 3kHz, otherwise lower. Series spread seems a foreign word for the driver. Furthermore, its intended working range is far outside the region around the resonance frequency that is prone to series fluctuations due to the design of tweeters. It is generally not recommended to separate tweeters> = 2x FR for nothing. Extremely commendable.

and the whole thing for extremely inexpensive 45 € (RRP) ...

Samuel HQ with Monacor SPH-175HQ and Peerless XT25 TG-30 / 04 (Vifa XT300 K / 4)

Technical data

  • Impedance: 4 Ohm
  • Sensitivity (2,83V/1m): 89 dB
  • Dimensions (HxWxD): 1100 x 238 x 361 mm
  • Crossover frequency: 1650 Hz
  • Frequency range (-3dB): 36 - 40000 Hz


  • High-grade stereo applications
  • Home theater as well without subwoofer
  • "Relaxed open listening"
  • free placement


  • extremely neutral frequency response: + -1,25dB of 50-23.000 Hz
  • Exceptional bass depth (-3dB 36Hz, -8dB 30Hz)
  • D´appolito arrangement => Intensive spatial representation of the sound
  • Both horizontally and vertically very well balanced frequency response at angles
  • low distortion, flawless burst-decay
  • optionally closed-box, bassreflex or a combination of both
  • => Very adaptable, even in "complicated" rooms

Test in Klang & Ton 04 / 2013 (excerpt)

Perfectly matched equipment: High-quality woofers and the ringradiator play together as built for each other.


Samuel HQ Angle Measurement 0-45 °
Klang & Ton measurement 0 °, 15 °, 30 °, 45 °

Flawless: On axis frequency response is in the range of plus minus one decibel from fifty hertz to over twenty kilohertz - the -3dBPoints are at 36 Hertz and 40 Kilohertz ...


It sounds balanced, sovereign and ready to do bad things when it comes to mean levels ... profound and dynamic bass ... discoloration-free mids ... The ring radiator ... unobtrusive and extremely smooth with a profound level of detail that only gradually draws attention to itself.


Clever driver combination, paired with perfect tuning, results in a box that does everything right.

For the full test on Hifitest.de


Tweeter: Peerless XT25 TG-30 / 04 (Vifa XT300 K / 4) / Test

Alternatively: Scan Speak R 2604 / 832000

Woofer: 2x Monacor SPH-175HQ

Klang & Ton 06 / 2012: The SPH-175HQ passed our test course with bravura... Very high-quality driver, which cuts a good figure both in two-way constructions and as a low-frequency specialist


building plan


Cost example (ehighend.de Stand 12 / 2017)

Buy cabinet kitsThomaier


Test Peerless DX25TG09-04 (Vifa XD-270 F / 4) at Waveguide WG-300 4 Ω dome tweeter with waveguide


Datasheet © www.heissmann-acoustics.de
Measurements in 20x40cm baffle, 10mm rounded, in 70cm distance at 2,83V. Level scaled to 1m.

The Waveguide was milled with a CNC adapter plate  mounted on the tweeter.

Vifa XD270F4 WG300 closeup

Directivity horizontal (0-90 ° in 15 ° steps)

Vifa / Peerless XD-270 F / 4 (DX25BG60-04) on Waveguide WG-300

Due to the waveguide system-related symmetrical elevation in the frequency band of 1-10kHz. This can be easily leveled with the crossover.

The Vifa Peerless XD-270 / F4 goes perfectly with the waveguide WG-300. Very even bundling without significant disturbances. The behavior> 10kHz can be described as outstanding. 20kHz are reached even below 45 ° with an almost full level.

The amplitude response drops below 45 ° of 2-18kHz by only 2,5dB! The 30 ° curve runs to 20kHz in a + -1,5dB tight tube. 20kHz are reached at full level.

The sonogram shows a bundling behavior that comes very close to the so-called Constant Directivity.

Sound pressure standardized at angles to 0 °

Vifa / Peerless XD-270 F / 4 (DX25BG60-04) on Waveguide WG-300


Burst decay

Minimal delayed decay by 2 and 20kHz. Otherwise perfectly.

Harmonic distortions

Vifa Peerless XD-270 / F4 (DX25BG60-04) & Waveguide WG-300 harmonic distortion

The harmonic distortion of the XD-270 F / 4 on the waveguide is excellent.

K2 remains below the 100% mark even at 1,2dB as of 1kHz. K3 moves from 1kHz between 0,04 and 0,3%.

Clatter components of higher order are in the (for me) no longer measurable range.

Separations from 1,2kHz are possible without hesitation, depending on the application and level requirements possibly even deeper.


Frequency response / directional behavior:5 5 out of stars
Range:5 5 out of stars
Power handling:5 5 out of stars
consisty:4.5 5 out of stars
Haptics:4 5 out of stars
Price-performance:5 5 out of stars


The Peerless / Tymphany DX25TG09-04 on the Waveguide WG-300 measures itself outstanding.

The possibility of building a loudspeaker that comes close to the requirements of constant directivity. Separations from 1,2kHz. Lowest harmonic distortion even at 100dB / m ...

Of course, a very interesting driver for Cinetor.


CNC adapter plate for various Scan-Speak and Peerless tweeters on WG-300 and PCT-300

There are some tweeters from Scan-Speak and Tymphany, all of which share the same front panel. One or the other of them also measures itself excellently on the P-Audio (PCT-300), or Monacor (WG-300) waveguide.

In order to connect the drivers cleanly with the sound guide, an adapter plate milled in CNC was created after many test series, which allows simple and very precise installation.

The following tweeters are suitable for the conversion

3D printed adapter plate in the shop

Construction of the adapter plate with "home remedies"

With a jigsaw, cordless screwdriver, router and the following step-by-step instructions, building the adapter plate yourself should not cause any problems. It doesn't even have to be measured 🙂 Let's go ...

  • Print out the PDF (included in the respective building folder) using Acrobat Reader (choose the “actual size” option!)
  • Size check: Outer diameter 120mm
  • Glue on a 9mm thick piece of MPX / MDF / screen printing plate (spray glue / glue stick ...)
  • Drilling the holes => upright drilling machine is an advantage!
  • With the circular milling device (each speaker should have one) 3mm deep to appropriate mark milling (D67mm)
  • Use the jigsaw to saw the inner hole and saw off the plate in the last step

From the practice with the "home remedy method" another additional tip from Thorsten (www.felbi.at)

If you glue your artwork directly onto the substrate (eg MPX), you will have the difficulty to get it down again later. For visual reasons, that bothered me and came up with the following idea: Before you glue your artwork on the MPX, just past the MPX with tape. Now the artwork will be cut to the size of the MPX board. Spray glue is then sprayed onto the package tape and allowed to dry for about 5 minutes (Note the spray adhesive is not on the paper spray!). Now the print template can be glued on.

Once all drilling and milling work has been completed, the package strap can easily be pulled down again from the MPX board.


First, the front panel of the tweeter must be removed. On some models, this is easily fixed with a silicone-like adhesive. In this case, use a large slotted screwdriver to "pry" it up discreetly as shown in the following picture. Work slowly and evenly. The screws on the front panel should of course have been loosened beforehand (TX10).

Dressing the waveguide neck

The adapter plate is placed on the sound guide and the neck is ground flat with circular movements (⇒ dust mask).

Finally, two recordings of the Scan-Speak D2604 / 833000 or 830000 & the Peerless XT25TG30-04 with waveguide


You do the conversion on your own responsibility! I accept no liability. Possibly. you lose your warranty claims during the conversion.

I made a lot of changes and nothing ever happened. I think the instructions are pretty "foolproof" 🙂

The plans of the adapter plate are the intellectual property of Heissmann-Acoustics.de, Alexander Heißmann. Any transfer requires my express consent.

... you can get a coffee from 1 € 😉

Test Peerless / Tymphany XT25TG-30 / 04 (XT-300 / K4) at the waveguide WG-300 / PCT-300 4 Ω ring emitter with waveguide

Datasheet © www.heissmann-acoustics.de
Measurements in 20x40cm baffle, 10mm rounded, in 70cm distance at 2,83V. Level scaled to 1m.

The Waveguide was milled with a CNC adapter plate  mounted on the tweeter.


XT25TG-30 / 04 Sound pressure at angles

Vifa XT-300 (XT25TG-30 / 04) WG300 Sound pressure at angles

System-related exaggeration in the frequency band of 1-7 kHz. Due to its symmetry, this can be easily equalized with the crossover. It is the purpose of a sound guide to act as an acoustic amplifier. The Vifa XT-300 (XT25TG-30/04) is an excellent match for the waveguide. Extremely even bundling without any disturbances worth mentioning. Due to the large dome (30mm voice coil), a slightly stronger directivity from 8kHz. Recommendation: plan a slight increase> 8kHz in the high frequency on axis.

XT25TG-30 / 04 Sound pressure standardized at angles to 0 °

Vifa XT-300 (XT25TG-30 / 04) WG300 Sound pressure normalized at angles

Vifa XT-300 (XT25TG-30 / 04) WG300 Sound pressure normalized at angles

Here, the frequency response was linearized on axis. The 2. Picture (sonogram) clearly shows the excellent uniform straightening behavior of the combination of XT-300 and the waveguide.

XT25TG-30 / 04 decay behavior

Vifa XT-300 at Waveguide WG-300 decay behavior

Minimal delayed decay by 2kHz. Otherwise perfectly.

XT25TG-30 / 04 harmonic distortions

Vifa XT-300 at the waveguide WG-300 harmonic distortion

As expected, the distortion decreases compared to the variant without waveguide. The XT-300 already showed very good distortion even without waveguide, but with a significant increase of K2 under 3kHz. With Waveguide the effect is also present but attenuated by about 5dB. In sum, very low distortion. Even with 100dB, everything from 2kHz remains below 1%. K3 moves at the measurable limit.


Frequency response / directional behavior:4.5 5 out of stars
Range:5 5 out of stars
Power handling:5 5 out of stars
Constance / Without Rating /:0 5 out of stars
Haptics:4 5 out of stars
Price-performance:5 5 out of stars


The Peerless XT25TG-30/04 and the Waveguide WG-300 are a very attractive combination for extremely level-stable installations, for example in the home theater. Can be used from 1,5 kHz. I think I'll test it out in Cinetor.