How to Calibrate your Speakers using REW and APO (for free)

[@msoles30]

Do you know how to do it with a home theater system with multiple speakers

[@donit.]

I never did it, but in theory it should work exactly the same. The EQ we apply is the same for every channel anyway, so it shouldnt matter if you have 1, 2, 4 or 6 speakers.

[@msoles30]

@@donit. how to get equalizer apo to read all five or seven speakers

[@MosesMontero]

Thank you so much, sir!

[@GianPaoloVecchi]

It seems to work, but why if I analyze with REW using or not using the EQ curve, the result is always the same? Equalizer APO works, as turning it off makes a difference.

[@akyhne]

It doesn't really matter that your microphone is cheap. Youre doing a very rudimentary calibration anyway. Sure youll get a better sound, but at least fix the clipping you can see, at 8:13. In the bottom left, it says maximum is 0,6 dB in red. It means clipping. No matter your volume level, when listening, youll have distortion at around 700Hz and 3.000 Hz. It us very easy to fix, though. Scroll diwn in the buttom of your "adam a7x 3.txt" in Equalizer APO, click the plus, go to "Einfache filtern", and select tge top one. In the English version, its called "Preamp (preamplification)". Choose it, and set tge gain to - 0,6. The "Maximum" in the bottom left should say 0,0 now. It doesn't really matter, if the text comor is still red, as long as the value is not positive. You will loose very little, and undetectable volyme level of your speakers, but youll have no clipping. Remember to save your file.

[@donit.]

Just because the maximum it's 0.6db doesn't mean it's clipping, it's only clipping if you were to play something full scale at exactly and only those frequencies (which is very unlikely). You're right though that I guess it would be more ideal if I brought it down another 0.6db, I'll do that when I'm back home.

[@akyhne]

@@donit. The value has nothing to do with how loud you're playing. You can think of the value, as if you opened an audio file in your favorite audio editor, like Audacity. You'll notice, that max. volume in any audio file, is 0 dB. If you increase the volume in any audio file, where peaks exceeds 0 dB, you'll get clipping. It's basically what is happening here.

[@donit.]

@@akyhne I don't think you can say it like that, it only means that it boosts some specific frequencies by 0.6db. most of the frequencies don't get boosted but cut though, so it's very unlikely that the resulting audio will have a higher peak value than before.

[@akyhne]

​ @Donit. Equalizer APO directly controls your DAC. A DAC has a limit. let's say, it's a 8-bit DAC. The highest number combination, is 11111111 or a value of 255. You cannot exceed that limit. So every value that is higher from EQ APO, will just be 11111111. It's like you're cutting off the top of the waveforms on a sound clip. It's easy to test. Just put these values in your txt file, just remember to edit the filter numbers. It's a simple boost of 16 dB, from around 0-100 Hz. Play some music. Low or high, it doesn't matter. You'll either hear the sound as clipping/distortion, or compression of the low tones. You can also just add some dB to your preamp, and hear the same, although it's harder to hear, when you're boosting the entire frequency range. And please do a search on "Equalizer APO clipping". You'll get loads of results about why you must not exceed the 0 dB boundary, on the "Maximum/peak Level".

[@donit.]

@@akyhne I know how clipping works, still it will only clip if I play something at one of the frequencies thats boosted and that sound has to be very close to clipping already and it has none of the other frequencies (because they are made quieter a lot more than those ferquencies get boosted, so it wouldnt clip). So yes, in that very specific case it can clip a little bit. It wont happen with 99.99% of music though.