Re: Controlling gain on microphone
Re: Controlling gain on microphone
- Subject: Re: Controlling gain on microphone
- From: Andy Peters <email@hidden>
- Date: Tue, 03 Jun 2014 15:52:17 -0700
On May 31, 2014, at 6:02 AM, Allison Newman <email@hidden> wrote:
> Yup, my bad. It would have perhaps been better to say that I was trying to amplify the input received from the microphone, not to actually increase the gain on the microphone itself. But that leads me to an interesting question - I’m no expert when it comes to handling audio, but I kind of expected that most microphones that you would connect to a Mac to not have gain control on them - but rather to simply spit out a signal that was optimized for the hardware. Am I wrong in this? At any rate, no matter how the gain on the microphone signal is handled, the technique needs to be applicable to all microphones that might be attached to the Mac, which is why I figured a software solution would be better...
>
> Le 31 mai 2014 à 14:25, Paul Davis <email@hidden> a écrit :
>
>>
>>
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>> On Sat, May 31, 2014 at 7:51 AM, Allison Newman <email@hidden> wrote:
>> >
>> > My application currently connects the microphone to the speakers, using AudioUnits to use my Mac as an amplifier, and it works just fine. I would like to be able to control the gain of the microphone using a slider, and was wondering if anyone had a suggestion of how to do it. Ideally, I’m looking for a solution that introduces as little latency as possible between the microphone and the speakers.
>> >
>> > I was hoping to find an AudioUnit that I could insert into the AudioGraph to do this, but at least my initial analysis seems to indicate that this is not the case.
>>
>>
>> There is some confusion here. The gain of the microphone is a hardware property. AudioUnits are generally blobs of code that carry out signal processing. If you mean you want to add gain to the signal, then an AudioUnit can do that. But it would quite suprising to use an AudioUnit to control the hardware gain on the microphone - this is generally controlled from system preferences and/or using APIs quite separate from AudioUnits.
FWIW, I did a USB audio device with hardware preamp gain and hardware output level control. The Audio Control interface tells the host the range and the granularity of each, so when you look at the device in the Audio MIDI Setup (and in other applications), the little sliders showed the actual ranges (20 dB to 60 dB for gain in 1 dB steps, 0 dB to -96 dB for output level in whatever step it was).
(Embarrassingly, Windows couldn't figure out how to show real gain numbers and instead just had its goofy scale.)
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