Datasheet © www.heissmannacoustics.de  
Measurements in DIN baffle in 70cm distance at 2,83V. Level scaled to 1m  
19mm ring radiator from Peerless, distributed by QuintAudio. Equipped with a 4mm front plate, a 4hole attachment, a "bead only design" as a membrane, a coupling volume and excellent measured values ...  
Vifa / Peerless XT19TD0004 (XT200 K4) sound pressure & impedance (dispersion) 
Outstanding linear frequency response. From 2,514kHz + 0,5dB!
Full level from 1,2kHz. Extremely goodnatured "rolloff". 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 lowviscosity ferrofluid. Their slightly different characteristics are completely meaningless, being far out of the usable range. 

Vifa / Peerless XT19TD0004 (XT200 K4) Sound pressure at angles (15 °, 30 °, 45 °, 60 °) 
Extremely consistent and a 19mm voice coil corresponding Rundstrahlverhalten.Idealer game partner for broadbeam 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 XT19TD0004 (XT200 K4) Decay behavior

Very smooth and fast decay over all frequencies.  
Vifa / Peerless XT19TD0004 (XT200 K4) harmonic distortion

Outstanding low distortion 3.order. From 2kHz at all measured levels <0,1%. The "goodnatured" K2 increases relatively sharply below 3kHz. A little bit of "enhancement" is built in. Higher order distortion components are practically not apparent. For very levelstable combinations, I recommend separations from 3kHz. Smaller 2way (e.g. with a 4 ″ TMT) can be separated by 2kHz.  
Rating

Summary


Keyword: ring radiator
Test Peerless / Tymphany XT25TG30 / 04 (Vifa XT300 / K4)
Datasheet © www.heissmannacoustics.de  
Measurements in DIN baffle in 70cm distance at 2,83V. Level scaled to 1m  
An extraordinary tweeter, equipped with a 5mm thick front panel, a 5hole attachment and a "bead only design" as a membrane.  
Vifa / Peerless XT300 K4 (XT25TG30/04) sound pressure & impedance (dispersion) 
Outstanding linear frequency response. Full level from 1,3kHz. Extremely goodnatured "rolloff". The efficiency is on average 91,5dB / 2,83V. One copy has a resonance frequency that is 20% higher, but this has no effect in the intended working range. Otherwise congruent course from 1,5 kHz. Very well. At the frequency response you have to look very closely to see whether there are 2 or 3 drivers. Practically congruent course from 600Hz.
Vlt. a little note at this point: I do not buy any preselected drivers ... With such a result, one might suspect that. 

Vifa / Peerless XT300 K4 (XT25TG30 / 04) Sound pressure at angles (15 °, 30 °, 45 °, 60 °) 
Very uniform omnidirectional behavior. Somewhat stronger directivity than with 25mm calottes. No criticisms. Recommendation: Tuning linearly to 15 °.  
Vifa / Peerless XT300 K4 (XT25TG30 / 04) 
Extremely smooth and fast swinging over all frequencies.  
Vifa / Peerless XT300 K4 (XT25TG30 / 04) harmonic distortion 
Outstandingly low 3rd order distortion. From 1,5kHz <0,1% at all measured levels. The "goodnatured" K2 rises relatively sharply below 3kHz. A little bit of "whitening" is built in. In the case of separations> = 2kHz, K2 should still remain below the perceptibility threshold, even at very high levels.  
Rating

Summary


Test Vifa Peerless XT25 / Neo4 (XT25SC9004)
Datasheet © www.heissmannacoustics.de  
Measurements in DIN baffle in 70cm distance at 2,83V. Level scaled to 1m  
Vifa / Peerless XT25 / Neo4 (XT25SC9004), a very levelresistant, small neodymium ring emitter, can be used wherever it gets tight ... 

Vifa / Peerless XT25 / Neo4 (XT25SC9004) amplitude response dispersion 
Good linearity. Full level already from 0,9kHz! With 91,5dB / 2,83V, the efficiency is average for an 4Ohm driver and sufficient for 95% of all applications. At 4khz there is an interference point that also shows up in the impedance response, but not in the decay behavior. With clever wiring of the Peerless XT25 / Neo4, you can "conjure up" a 2dB dip around 3,5kHz from the cant, which is usually perceived as very pleasant. D. The amplitude responses of the two drivers are practically congruent. Very good 

Vifa / Peerless XT25 / Neo4 (XT25SC9004) Impedance (Scatter)

The 830Hz resonant tip of the ring radiator shows that no ferrofluid was used. A minimal disturbance can be seen in 4kHz, which also shows in the amplitude response. The impedance paths of the measured drivers are congruent. Exemplary.  
Vifa / Peerless XT25 / Neo4 (XT25SC9004) Sound pressure at angles (090 °) 
Due to its large diaphragm (30mm diameter) the ring radiator straightens more than 25mm calottes, but very evenly. Many Tüfftler appreciate this property when coupling the Peerless XT25 / Neo4 to a waveguide.  
Vifa / Peerless XT25 / Neo4 (XT25SC9004) decay behavior 
Overall, very smooth and rapid decaying over all frequencies. No criticisms.  
Vifa / Peerless XT25 / Neo4 (XT25SC9004) harmonic distortion

K3 is extremely low up to 2kHz, below which it rises steeply. K2 rises evenly below 3kHz. However, in my opinion nothing stands in the way of a separation of around 2kHz. In combination with two 5 ″ drivers, I already disconnected at 1,7kHz and the dome copes with that without any problems. Even there, K2 hardly scratches the 1% mark. Overall really good values.  
Rating

SummaryLevel fixed small tweeter which is very universally applicable. Due to the large membrane, it can be very loud and can be used from 2kHz. Due to its "special" directional effect, the ring emitter is very well suited to be combined with a waveguide (eg WG300 from Monacor). Then the distortion drops below 2kHz and nothing stands in the way of a separation of 1,5kHz. Predestined is the Peerless XT25 / Neo4 for d'appolito,  and all other arrangements in confined spaces. To emphasize is the very small dispersion. The two measured specimens of the ring radiator are practically congruent both in amplitude and impedance. 
