Driver testing

The drivers at stake

Peerless SLS 830669, 12″ coated paper bass.

Scan-Speak Discovery 18W/8434G00, 7″ fiber glass mid bass.

Accuton C50-8-044, 2″ceramic midrange.

Tectonic (Hiwave) TEBM36S-8/A, 65x65mm BMR fullrage.

Dayton AMTpro-4, large AMT tweeter.

Dayton AMTmini-8, miniature AMT tweeter.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

We did not calibrate the SPL for each measurement. The SPL is subjectively at the same level, which in practice means that they may vary several dB form test to test. Therefore these measurements are to be seen as indicators for performance and not absolute measure to be closely compared.

In general the SPL during measurement is “high listening level”, about 100dB at 1m.

Test result

Peerless SLS 12″ mounted in approximately 60l closed cabinet. A smooth frequency response with mild breakup. 2:nd order distortion (blue) are good, 3:d order distortion (red) is very good for low frequencies but limit the useful bandwidth to about 300z. We have tested this driver in a 2-way design crossed at 1kHz. While this will work, its 3:rd order distortion in lower midrange leave you wanting for more clarity and vocal presence. Bass performance (when EQ:ed) is tight and dry.

Scan-Speak Discovery 7″ mounted in approximately 5l closed cabinet. The purpose with this test is to evaluate its behavior as a midrange in a large 3-way design. A smooth frequency response with no sharp breakup. 2:nd (blue) and 3:d (red) order distortion is decent and as expected from a simple motor design. Preferably crossed below 2kHz to limit 3:d order distortion. Sonically decent performer but leaves you wanting for more midrange clarity.

Accuton 2″ midrange mounted on small baffle. A fairly smooth frequency response with need for mild EQ. A very clean 2:nd (blue) and 3:d (red) distortion. Useful from 500 to 5kHz.

Dispersion plot of the same accuton mid showing its useful upper limit. Measurement are taken 0-90degree off-axis.

Tectonic BMR fullrange mounted in approximately .3l closed cabinet. In this measurement an hp-filter at 300z was used for speaker protection. Fairly smooth frequency response with need for mild EQ. 2:nd (blue) and 3:d (red) order distortion are good from 1.5kHz and up. This driver can be used as a wideband tweeter.

Dispersion plot of the same Tectonic BMR driver (here measured fullrange) showing the very impressive dispersion of this fullrange driver. Measurement are taken 0-90degree off-axis. Apart from high dispersion at 3kHz its response is just mildly tilted downward at higher frequencies, a very natural behavior.

Dayton AMTpro-4 freestanding. This measurement was done at another time from all other measurements in this post and therefore the SPL may deviate more from the other measurements. Anyhow, the SPL was quite high. The frequency response is useful if EQ is applied. Distortion is extremely low. Sonically this translates to very high transparency. The biggest drawback with this driver is its very limited vertical dispersion. Unfortunately we have no measurement to show this but the driver need to be pointed directly at you. If it is pointed at you when seated, when you stand up the sound totally collapse, which disqualifies the driver for us. A very large line-array with 4 to 5 drivers could be interesting, but very expensive.

Dayton AMT mini mounted on small baffle. Frequency response is fairly smooth. 2:nd (blue) and 3:d (red) order distortion is good. Especially nice is the fact that the distortion is maintained low several octaves below its low frequency rolloff. Passive filtering of this driver to, lets say the accuton C50 should be easy with very few components.

Dispersion plot of the same Dayton AMT mini. Measurement are taken 0-90degree off-axis. Very useful and comparable with other tweeters with similar size.