Mixer/sound driver volume levels and distortion
Hi all, I have onboard AC97 sound, according to kmix my system automatically set itself up with the 'VIA 8237' driver, which is probably right. I have a good old analog connection to an amplifier. If I set master and PCM to 100% the volume is at a good level but is very distorted. If I move both down 'a bit' then the distortion goes away but it's all a bit unscientific as to how much that 'bit' is. If I leave PCM at 100% and move Master about it gets quieter but is always distorted. In Windows on the same hardware, setting all mixers to 100% seems to output a good, loud, non distorted sound, I'd guess at the 'line level' that my amp is expecting. Is there a setting somewhere in the (ALSA) driver to set the maximum output to 'line level' so I can set kmix at 100% and get good volume and no distortion? There is an 'External amplifier' switch in kmix but it appears to have no effect. I've had a good root around on Google and the answer appears to be 'turn the mixer volumes down a bit' - e.g.: http://alsa.opensrc.org/index.php/TroubleShooting#Sound_can_be_heard_but_it_... There must be something more accurate? If the Windows drivers have some built-in setting can it be replicated? Cheers Neil
Hi Neil
Is there a setting somewhere in the (ALSA) driver to set the maximum output to 'line level' so I can set kmix at 100% and get good volume and no distortion?
Semi-recently in alsamixer (alsamixer v1.0.14 is what i'm using at the moment), I noticed a dB gain read out at the top, adjust this to 0 and good volume with no (extra(!)) distortion. My current card, is a built-in realtek alc888, and 100% is gain 0.00, however on a previous card (which i removed because of driver issues) it was something like 84%. Rob.
Rob... magic! I hadn't noticed that gain value before, but then I don't use alsamixer often. That confirms my experimentation - 100% master is gain 0, and 74% PCM is gain 0. I've seen '74%' bandied about on forums before, this puts a rubber stamp on it :-) Now to see if there's a way to configure ALSA to put some sort of loading/offset on the PCM mixer so 74% is the maximum... Cheers Neil Rob Page wrote:
Hi Neil
Is there a setting somewhere in the (ALSA) driver to set the maximum output to 'line level' so I can set kmix at 100% and get good volume and no distortion?
Semi-recently in alsamixer (alsamixer v1.0.14 is what i'm using at the moment), I noticed a dB gain read out at the top, adjust this to 0 and good volume with no (extra(!)) distortion. My current card, is a built-in realtek alc888, and 100% is gain 0.00, however on a previous card (which i removed because of driver issues) it was something like 84%.
Rob.
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On Thu, 2007-10-18 at 13:56 +0100, Neil Sedger wrote:
Hi all,
I have onboard AC97 sound, according to kmix my system automatically set itself up with the 'VIA 8237' driver, which is probably right. I have a good old analog connection to an amplifier.
If I set master and PCM to 100% the volume is at a good level but is very distorted. If I move both down 'a bit' then the distortion goes away but it's all a bit unscientific as to how much that 'bit' is. If I leave PCM at 100% and move Master about it gets quieter but is always distorted.
Funny I have the same chipset here but a different problem, I don't get distortion but the output level seems lower than it should be (I generally have to run with my amplified speakers volume turned right up and the Master set to 100% with the PCM set to at least 80% to get to a good moderate listening level) Although it could be that I am going deaf in my old age :)
participants (4)
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Neil Sedger -
Rob Page -
Steve -
Wayne Stallwood