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How to Remap Analog to Digital Equalization?

Posted: Sat Mar 28, 2015 3:16 pm
by MachineGhost
I have a vintage Pioneer analog amplifier that has only a 10dB+/- 5-band equalizer that is set to fix the flaws with the speakers paired with it (some kinda of Bose).  Unfortunately, it seems to be non-standard frequencies, so I'm not 100% sure how to convert the settings to a non-standard 9-band digital equalizer for use with the same speakers.  Here are the settings from the analog amplifier:

100Hz -5
330Hz +4
1K +10
3.3K 0
16K -9

My best guess for the digital equalizer is this:

63Hz -10
125Hz -5
250Hz +0
500Hz +8
1K +10
2K +4
4K -1.5
8K -5
16K -9

I cannot adjust it by ear or microphone, so does anyone have any comments?

Re: How to Remap Analog to Digital Equalization?

Posted: Sat Mar 28, 2015 10:50 pm
by Mark Leavy
A few small tweaks produces a good fit.

[img width=600]http://i57.tinypic.com/63vn05.png[/img]

Re: How to Remap Analog to Digital Equalization?

Posted: Sun Mar 29, 2015 9:44 am
by MachineGhost
Wow, thanks!  I guess I'm not that math stoopid after all :D  Do you think its hitting the exact setting on the in-between frequencies, i.e. 100, 330, 3300?

Re: How to Remap Analog to Digital Equalization?

Posted: Sun Mar 29, 2015 1:46 pm
by Mark Leavy
MachineGhost wrote: Do you think its hitting the exact setting on the in-between frequencies, i.e. 100, 330, 3300?
Not exact, but short of knowing the exact filter design for each stage of both equalizers, this is as good an estimate as you can get.
It would probably sound better if you had a musician friend come over and just tune it up by ear.

If you want to get creative.  You can download some "pink noise" files from the internet, play them through your speakers and use a spectral response app on your iphone to "listen".  Adjust the equalizer until the power spectrum is mostly flat.