Ilkka, Until you actually make blind testing a part of your subwoofer tests, you are running half a test.
You also set abritrary test parameters which favor SVS. For example, you decided to use this "10 % THD + N" for your max output charts ..
Yet, in comression tests, the EP-600 delivered 99 dB @ 20 Hz ... Someone looking at this chart would think the EP-600 to be a poor performer. You KNEW this when you posted that chart.
I, along with several dozen other people (including Bossobass, who knows a few things about subwoofers) in our home, AND every other reviewer who has experienced the EP-600 has raved about its performance. At NO time is distortion audible with the EP-600.
And yet, Ilkka, I have seen several e-mails in which you told people about it having "cone cry, farting ... etc ..."
That is impossible with the EP-600. The DSP will not allow that to happen.
The EP-600 will deliver, @ 20 Hz, a 99 dB signal @ 2 meters ground plane with no audible distortion. The 86 db you list in the chart is totally mis-leading.
Yet, HERE is how you do the comparison to the PB10-ISD ...
According to your compression charts, the PB10ISD and the EP-600 match @ 20 Hz ... But, using your "10%" number, you got to make the SVS the winner.
You also still have this diatribe in your review ...
There are some small problems with the amp/gain control, which are actually preventing me from doing proper listening tests. The amp has some sort of a mute circuit and here is an explanation from Ian Colquhoun (president of the Axiom) how it works.
“The mute circuit in the EP600 is controlled by an algorithm and works completely differently than an analog mute circuit. The circuit will mute a single tone or even broadband non dynamic noise at 90 dB by 10 dB if you put the SPL meter 12 inches in front of the sub-woofer and on the floor. It will not however, do this to a music signal at anywhere near this dB level. The DSP algorithm is effectively analyzing the wave form to accomplish this. There are enormous advantages to this over analog in that the sub is capable of muting noise and the dreaded 50 Hz (60 Hz here) hum at higher levels without muting the music signal. This eliminates the problem of the sub not ever going into mute because of noise or hum, and the inverse of not coming on when it should.”
As Ian explained, the mute circuit also mutes non dynamic broadband noise, which means it will also mute a calibration tone from say AVIA disc. And that it what it really does. That 90 dB at 12” translates pretty well to 85 dB at 2 meters in-room, so when the calibration tone is being played, the tone jumps up and down by 10 dB, since the subwoofer isn’t quite sure if he should mute it or not. So why not calibrate to 90 dB then? One could do it, but it really doesn’t help at all, since the signal jumps also with a normal music signal!
That’s right. I can hear and measure a clean 10-11 dB jump at a certain dB level (around 80-90 dB). And this level of course happens to be in the middle of the usual listening level, so it basically turns listening into an impossible mission. But as you read it should not happen with a dynamic music signal.
I have discussed with these problems with the Axiom and I am sending my unit back for a check. If it is proven that this gain problem affected on some of the measured data, I will of course measure the new unit as soon as possible, which means the spring shootout.
You cannot do a listening evaluation with the EP-600 ?
I have tried to replicate the problem you had with the Avia disc, TrueRTA, Emotiva Test Tones ... etc ... it is no harder to calibrate than any other subwoofer.
You promised, in writing, to send the subwoofer back to Axiom. That promise is still in your review.
