Re: setting mic volume
Re: setting mic volume
- Subject: Re: setting mic volume
- From: Jeff Moore <email@hidden>
- Date: Fri, 31 Oct 2008 16:45:56 -0700
One device with volume controls is going to behave pretty much the
same as another device with volume controls, at least from a
programmatic point of view. So, testing with the built-in microphone
on the Mac should be quite helpful.
On Oct 31, 2008, at 4:11 PM, Daniel Birns wrote:
Perfect. One more question:
I don't have a music store, or budget to go out and try all the
audio preamp units in the market. I need one to test with.
Does anymore know of a preamp device for microphones that supports
volume controls?
Thanks.
--Daniel
On Oct 31, 2008, at 4:03 PM, Jeff Moore wrote:
On Oct 31, 2008, at 3:58 PM, Daniel Birns wrote:
Thank you. Okay, I'll be more specific: is it possible to
control an outboard preamp setting with CoreAudio?
Sure, but only if the device let's you by providing volume controls.
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?
Absolutely. But again, only if the device let's you by providing
volume controls
I think I understand the issue on low-end, or speech, equipment.
It's not a matter of high end or low end, speech or music, etc.
Rather, it is a matter of what the device can do. There are devices
out there that just don't allow for you to do what you want.
The best you can do is to use the APIs provided to discover whether
or not the device in question has the support you are looking for
and act accordingly.
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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Jeff Moore
Core Audio
Apple
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Jeff Moore
Core Audio
Apple
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