Re: setting mic volume
Re: setting mic volume
- Subject: Re: setting mic volume
- From: Daniel Birns <email@hidden>
- Date: Fri, 31 Oct 2008 15:58:07 -0700
Thank you. Okay, I'll be more specific: is it possible to control an
outboard preamp setting with CoreAudio? What I want to do is automate
volume levels on high-end recording equipment, like Duet, to ensure
the best possible audio coming in to the mac. This means I must
actively change the preamp volume when it approaches clipping (or if
it has clipped), and I need to raise the volume if too little signal
is coming in.
Is there equipment with preamps where I can do this?
I think I understand the issue on low-end, or speech, equipment.
--Daniel
On Oct 31, 2008, at 3:49 PM, Jeff Moore wrote:
On Oct 31, 2008, at 2:53 PM, Daniel Birns wrote:
I've tried HALLab on the Duet, and apparently they expose output
mute and output volume but nothing else. Apparently Maestro is
doing the communications in a proprietary way? That is, the output
mute and volume button and slider both work, but all the input gui
is greyed out (except for the channel setting).
Does this sound true?
Yes.
If so, are you aware of any other similar devices that support
input volume control through CoreAudio (HALLab)?
There are plenty of devices out there that don't have any volume
controls. You don't have to look any further than the built-in SPDIF
devices that are on several of our machines. Those devices have no
volume controls at all.
I'm looking to write software that, among other things,
automatically controls preamp volume. Perhaps I can only support
certain devices, which would be fine. I just need to know which
ones support this.
The way to know is to ask via the HAL's API, AudioObjectHasProperty().
On Oct 31, 2008, at 11:15 AM, Jeff Moore wrote:
You'll want to take a look at HALLab from the sample code in our
SDK. It shows how to twiddle the various knobs an audio device
might have.
On Oct 31, 2008, at 5:23 AM, Daniel Birns wrote:
Is there a programmatic way to set mic volume at the hardware
level.
To give an example: I have an Apogee Duet, which is a firewire
device that, among other things, has a preamp and 2 mic inputs.
You can control the volume with a knob on the Duet, or with
software, called Maestro, from Apogee. Can I control that volume
from an Audio Unit? Or from a standalone program, like Maestro?
--
Jeff Moore
Core Audio
Apple
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