Re: mixer volumes
Re: mixer volumes
- Subject: Re: mixer volumes
- From: David Reaves <email@hidden>
- Date: Sat, 12 Feb 2011 12:07:36 +0100
Although a full-blown limiter is overkill for simple mixing, a limiter is pretty simple in concept.
You need to measure the absolute peak value of the incoming audio, determine if it is over the desired threshold, and if it is, adjust your output signal by multiplying the incoming signal by a factor that is computed to exactly counterbalance the audio over threshold (for infinite ratio brickwall control).
Unless you can afford to delay the audio an amount corresponding to attack time, I would use an instantaneous attack on the detected control signal, and a decay (release) filter of at least a few tens of milliseconds to reduce distortion caused by direct envelope following of the control signal on the audio.
Such a limiter can be implemented in just a few lines of C code, or you can create an object.
Kind Regards,
David Reaves
On Thu, 10 Feb 2011 16:07:55, Brian Willoughby <email@hidden> wrote:
>
> On Feb 10, 2011, at 06:05, email@hidden wrote:
>> Maybe I have to reduce the volume from the beginning so i can
>> increase it when new sounds are added.
>
> I do not understand how that would help, but go ahead and give it a try.
>
>
>> A limiter would be ok, too, but as I'm programming for iPad, I
>> would have to write it myself. Hmm, maybe I could try that.
>
> I'm fairly certain that Apple's AUPeakLimiter is available from the
> same pool as the multichannel mixer AU. It doesn't have the full
> flexibility of a commercial limiter, but it gets the job done.
>
> Brian Willoughby
> Sound Consulting
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