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:


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:

... 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 😉








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

  1. A great and objective comparison test.

    All acoustic properties and the price difference aside - the DXT-MON is far, far more beautiful to look at in my eyes!

    1. I've had the KH120 for years now, but they're really not very nice in a living room.
      Now to the sound:
      Yes, they are very good as long as they play a good recording.
      If the recording does not work, the KH becomes annoying with harsh heights, etc.
      I also don't always find the tone colors so great.
      It was developed as a tool and not deliberately for enjoyment listening.
      I already had spendor BC1, if you love the English sound, you should keep your hands off von Neumann.
      In turn, the KH can vote like no other.
      But all neumann monitors are very sober, dry, trimmed for the studio.
      They should also be in acoustically good rooms.
      Nevertheless, if you read this here, the DXT MON seems to be a real alternative.
      Has anyone actually ever compared the DXT with a comparable box from AOS (Scan speak Revelator or Illuminator with 15 cm chassis)?
      From AOS there are only those with a straight front.
      Visually similar kits with scan speak are only available from
      Hobby hifi or sound and tone.
      But I don't really trust them, I had recreated them twice with a Görlich chassis. Well, got rid of a lot of money, but they weren't that special.
      Switch circuits from HH and KUT are also viewed critically from time to time.
      The DXT Mon and all the text about your development as well as the measurements look pretty good.

      1. Hello Gerhard,

        have been using the DXT-MON for a year now. They run on a Yamaha A-S2100, a benchmark DAC2D in the front end or on the turntable with Denon DL103R pickup on the integrated MC phono input on the amplifier.
        Well, I can't offer a comparison with a small AOS, but a comparison with the somewhat older AOS Studio 24XL (the one with the extremely expensive ring radiator and the aluminum spacer rings for the 15cm Revelator TMT). Well what can I say, I'll make it short: I sold the Studio 24.
        The DXT-MON just sound really good from every perspective. When the system is running and you come around the corner into the room, you can see from a distance that the timbres are just right. When you hear a piano concert from the next room with the door open and think to yourself: That fits, then it fits. But that doesn't mean that you can only listen from a distance. Only then does it look really nice in the stereo triangle. By the way, the bass depth of these small speakers should not be underestimated. Well, the lowest octave is missing, but what you hear in bass-heavy music is the finest. And don't forget: the loudspeaker is also very suitable for TV sound and offers excellent speech intelligibility. Film sound is also wonderful.
        In my opinion, the perfect omnidirectional behavior of these loudspeakers is a significant advantage over many high-end systems, regardless of the price. The most expensive chassis are of little help if the radiation behavior is not consistent.

  2. As the owner of a pair of the KH120, I recently had a friend visiting me who had his newly built pair of the DXT-Mon with him. We heard and measured the loudspeakers under exactly the same acoustic conditions. There were clear differences in terms of sound and measurement in the deep bass and treble. The KH120 developed far more low-frequency energy below 100Hz in our test, but the DXT-Mon was fresher and livelier (stage, localization sharpness and detachment from the speakers were very good for both pairs). With the EQ of the KH120, the acoustic and metrological differences could initially be reduced (KH120: + 1dB for the high frequency, -3dB for the lower mids, -1,5dB for the bass) but the DXT-Mon was still the clear winner in terms of sound . It should also be mentioned that I always run the KH120 myself with a DSP for room correction, but the test was first without EQ and then only with the onboard means of the KH120 (the DXT-Mon was already "exactly right"). A clear building recommendation from me!

  3. The KH120A is perfectly in phase at crossover on-axis while the DXT-MON is not in phase on-axis.
    The KH120A has put the woofer more forward and the tweeter more back in the waveguide and combined they are giving the right amount of vertical distance to the acoustic centers of the woofer and tweeter so they are in phase, no phase correction needed in the crossover. The DXT-MON has the tweeter slightly back in the waveguide too but no forward woofer and the result is that the acoustic center of the tweeter is actually more forward than the acoustic center of the woofer, hence they are not alligned. This is not corrected for in the crossover.
    1.8kHz when listening on the DXT-MON.
    I would like to add a point to the KH120A for this ..

    1. Hello Marcel
      Thanks for your comment. I have to contradict you unfortunately.
      Althoug the voice coils of the Kh120A are closer to each other than those of DXT-MON, Kh120A's woofer is even more delayed than DXT-MONs! The woofer delays are about 0,24ms (~ 8,2cm) vs. 0,18ms (~ 6,5cm) [KH120A / DXT-MON].

      Here both steps are compared:

      Step response KH120A vs DXT-MON

      And ...
      DXT-MON is very well in phase at the crossover point.
      You can see that eg. In the vs-zero chart:

      kind regards

  4. I am new to speaker DIY, and trying to understand this a bit more.

    On the Heismann website there are two designs for DXT-MON, one with a passive radiator and another with a port. IIRC. Both of these designs are passive monitors (with passive crossover kit parts IIRC), with no specification of any amp.

    Which one of the versions of DXT-MON is compared to the Neumann KH120's?

    If I wish to build the same version of the DXT-MON which has been favorably compared with the KH120, in this review, exactly what would I need to order, and from which company?

    Will by DIY effort just do the assembly of the kit, or do I therefore need to build the wooden case myself?

    Is there any provision in the wooden case for mounting the hypex amplifier (eg cutout).

    Many questions indeed, and thanks for responding ..

    1. Hello!
      I did not compare the passive radiator version (8l) to the KH120A. The BR version goes even deeper, but needs a bigger enclosure (9,5l). If size doesnt matter I would recommend to build the 9,5l version (PR or BR).
      You can buy the technical kit in my shop if you live in the EU. If not, you can buy the plan and then get the parts from any dealer in your country.
      The housing / cabinet you have to build anyways.
      I used the hypex as an external unit. You are free to put it in the cabinet. But it needs its own chamber.
      Meantime I would prefer to use a mini-dsp setup.
      DSP setups are available for Hypex and Mini-DSP systems.

      I hope I could answer your questions!
      Best regards

  5. Hello Alexander, you write you would prefer the mini DSP to a Hypex module. How come? Aren't the Fusion amps even better (converter, fewer boxes standing around ...)?

      1. Dear Alexander,

        Do you mean there will be a version of the DXT-MON with a Fusion amp and active xo? I would be very interested in building that. It would make an even better competitor for high-end studio monitors!



  6. Hallo,
    I built the ScanSpeak 15er with a Morel 110 in one. A. 10 liter housing. BR. Solid oak.
    The latest thing is a Speak 18w4531g01 with an Eton ER4 ... also BR. Everything passive.
    Now I've got the Wavecor wf182bd10. And I already had the matching Seas tweeter in my pool.

    When everything is ready I can report if necessary.


    1. Hello Klaus,

      I would be very interested in the result, especially since I have the DXT-MON and an AOS S24XL had to give way.

      LG Walter

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