Re: Line In Imbalance
Re: Line In Imbalance
- Subject: Re: Line In Imbalance
- From: "Michael C. Thornburgh" <email@hidden>
- Date: Sat, 2 Mar 2002 12:39:28 -0800 (PST)
this is a known and bugreported bug. see
http://lists.apple.com/mhonarc/coreaudio-api/msg00909.html
you can fix it on your system if you have the darwin source.
-mike
>
Subject: Line In Imbalance
>
From: Chris Luth <email@hidden>
>
To: <email@hidden>
>
Date: Fri, 01 Mar 2002 15:30:07 -0900
>
>
I think I posted something about this problem some time ago, but somebody
>
asked me if I could clarify the problem. Well, I9ve finally gotten around to
>
it, so here it is.
>
>
When I attempt to record an analog line in signal, adjusting the gain of any
>
recording program results in only changing the gain of the right channel.
>
Here's some info that might help clarify the problem, using Daisy, an
>
example source code given in Developer->Examples->CoreAudio->HAL->Daisy.
>
>
OS: 10.1.2
>
Computer: Apple PowerMac G4 350 PCI Graphics (Yikes! board)
>
>
_s represent unchecked boxes, Xs represent checked boxes. --^-- represents
>
the position of the fader.
>
>
For best results, the diagrams below should be in Courier New, 12 pt.
>
>
--Input Channel Volume & Mute-----------
>
>
ch mute scalar db playthru
>
0 ^----[Fader]------- _ 0.0 0.0 X
>
1 ^----[Fader]------- 1 _ 0.00 0.00 _
>
2 ^----[Fader]------- 1 _ 0.00 0.00 _
>
3 ^----[Fader]------- _ 0.0 0.0 _
>
4-8 similar to 3
>
>
--Input Channel Volume & Mute-----------
>
>
ch mute scalar db playthru
>
0 ^----[Fader]------- _ 0.0 0.0 X
>
1 -----[Fader]------^ 1 _ 1.00 22.50 _
>
2 -----[Fader]------^ 1 _ 1.00 22.50 _
>
3 ^----[Fader]------- _ 0.0 0.0 _
>
4-8 similar to 3
>
>
Only channels 1 and 2 have active faders (the rest are grayed out) and only
>
channel 0 had an active playthru checkbox.
>
>
When sliding the fader for input channel 1 up, the sound output goes up in
>
the right headphone, but not the left headphone. Bringing the channel 2
>
fader up also makes the sound louder in the right headphone and not the
>
left.
>
>
Here's what's interesting...if you bring the channel 1 fader all the way up,
>
and then you begin to move the channel 2 fader up from 0, the sound output
>
in the right channel is changed to reflect the position of the channel 2
>
fader...as if it is overriding the channel 1 fader (i.e. it gets soft, back
>
down to 0.00db, and then moves up to 22.50 as you move the channel 2 fader
>
up to the top).
>
>
So it's as if both channel 1 and 2 faders are only affecting the right
>
channel input. If you open an audio recording program and adjust the
>
recording gain from within the program with Daisy open in the background,
>
you'll see both channels 1 and 2 faders moving up as you increase the gain.
>
As you might suspect from the other info I've given you, it only affects the
>
right channel's input levels.
>
>
Right above the Input section is the Output section, and it's laid out
>
similarly. In fact, here's a typed-up version:
>
>
--Output Channel Volume & Mute-----------
>
>
ch mute scalar db
>
0 ^----[Fader]------- _ 0.0 0.0
>
1 -----[Fader]------^ 1 _ 1.00 0.00
>
2 -----[Fader]------^ 1 _ 1.00 0.00
>
3 ^----[Fader]------- _ 0.0 0.0
>
4-8 similar to 3
>
>
Funny thing is, adjusting the channel 1 fader affects the left channel, and
>
adjusting the channel 2 fader adjusts the right channel. Why is this not the
>
case with the input channels?
>
>
This problem affects my ability to record analog line in signals
>
effectively. Help and a solution would be nice. Just to note, this problem
>
does not occur when I reboot in OS 9.
>
>
Thanks,
>
Chris
>
_______________________________________________
>
coreaudio-api mailing list | email@hidden
>
Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/coreaudio-api
>
Do not post admin requests to the list. They will be ignored.
_______________________________________________
coreaudio-api mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/coreaudio-api
Do not post admin requests to the list. They will be ignored.