Re: setting mic volume
Re: setting mic volume
- Subject: Re: setting mic volume
- From: Jeff Moore <email@hidden>
- Date: Fri, 31 Oct 2008 16:03:37 -0700
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
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Coreaudio-api mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden
--
Jeff Moore
Core Audio
Apple
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Coreaudio-api mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden