Re: CoreAudio and equalization
Re: CoreAudio and equalization
- Subject: Re: CoreAudio and equalization
- From: Paul Russell <email@hidden>
- Date: Fri, 28 Jun 2002 16:08:27 -0700
Thanks for everyone's helpful help!
Things are better. However, some fuzz still remains if I try to
boost the desired frequencies more than a modest amount (certainly
much less than a clean sounding boost in a professional audio
application). Making the adjustment anything more than 2.0 or 3.0
starts a noticeable fuzz. It isn't the result of the signal
clipping, although it certainly is worse then.
I thought perhaps it might be the code I use to determine what
buffer to alter for the particular frequency, as I am getting
strange results on the upper bands - 10000-16000hz. Is there an easy
way to determine which buffer corresponds to which frequency?
i) are you initialising the imaginary part of your time domain input
buffer correctly, i.e settign all teh imaginary parts to zero
(assuming this is a complex FFT routine) ?
ii) are you maintaining symmetry in the frequency domain ? For each
frequency there are two corresponding bins (the positive and negative
frequency) whose values should be a complex conjugate pair. You need
to scale both of these bins by the same factor otherwise you will end
up with a complex time domain signal when you do your IFFT, and the
Mac hardware does not support playback of imaginary components (;-)).
Paul
--
| Paul Russell email@hidden |
| ARC Software Ltd
http://www.arc-software.com |
| Santa Cruz, CA |
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