[alsa-devel] Output levels on SBLive! 5.1 on ALSA vs WIndows
Hello,
I am using an SBLive! 5.1 sound card (emu10k1 chipset) with 6 channel output. Due to the nature of my work, I need to be able to play sound through all 6 channels at the same output level to an amplifier.
Using Linux and the emu10k1 ALSA driver, I measured output voltage levels on an oscilloscope while playing a sine wave on all 6 channels, and I got three different output voltage amplitudes for the front, rear and center/subwoofer channels. Repeating the same test with the same card on WIndows using the Creative SBLive drivers from their website, I am able to get the same output voltage amplitude on all 6 channels. For both tests, all output levels in the relevant mixers were set to their maximum levels.
I would like to know if this output normalizing 'feature' of the SBLive Windows driver can be found in the emu10k1 ALSA driver, or in any other ALSA driver. Failing that, is there any other solution to set output levels in the driver, or am I doomed to twiddle in alsamixer to get the output levels that I want?
Thanks in advance.
At Mon, 18 Jun 2007 17:37:46 +0800, ChernYue Kwok wrote:
Hello,
I am using an SBLive! 5.1 sound card (emu10k1 chipset) with 6 channel output. Due to the nature of my work, I need to be able to play sound through all 6 channels at the same output level to an amplifier.
Using Linux and the emu10k1 ALSA driver, I measured output voltage levels on an oscilloscope while playing a sine wave on all 6 channels, and I got three different output voltage amplitudes for the front, rear and center/subwoofer channels. Repeating the same test with the same card on WIndows using the Creative SBLive drivers from their website, I am able to get the same output voltage amplitude on all 6 channels. For both tests, all output levels in the relevant mixers were set to their maximum levels.
I would like to know if this output normalizing 'feature' of the SBLive Windows driver can be found in the emu10k1 ALSA driver, or in any other ALSA driver. Failing that, is there any other solution to set output levels in the driver, or am I doomed to twiddle in alsamixer to get the output levels that I want?
Did you check the dB level appearing in mixer? The recent version of ALSA shows dB level in alsamixer and amixer. Note that the "Master" and "PCM" controls are applied only for front channels. So, set them to 0dB and control the volume via Wave* digital mixers.
Takashi
On Tuesday 19 June 2007 18:59:01 Takashi Iwai wrote:
At Mon, 18 Jun 2007 17:37:46 +0800,
ChernYue Kwok wrote:
Hello,
I am using an SBLive! 5.1 sound card (emu10k1 chipset) with 6 channel output. Due to the nature of my work, I need to be able to play sound through all 6 channels at the same output level to an amplifier.
Using Linux and the emu10k1 ALSA driver, I measured output voltage levels on an oscilloscope while playing a sine wave on all 6 channels, and I got three different output voltage amplitudes for the front, rear and center/subwoofer channels. Repeating the same test with the same card on WIndows using the Creative SBLive drivers from their website, I am able to get the same output voltage amplitude on all 6 channels. For both tests, all output levels in the relevant mixers were set to their maximum levels.
I would like to know if this output normalizing 'feature' of the SBLive Windows driver can be found in the emu10k1 ALSA driver, or in any other ALSA driver. Failing that, is there any other solution to set output levels in the driver, or am I doomed to twiddle in alsamixer to get the output levels that I want?
Did you check the dB level appearing in mixer? The recent version of ALSA shows dB level in alsamixer and amixer. Note that the "Master" and "PCM" controls are applied only for front channels. So, set them to 0dB and control the volume via Wave* digital mixers.
Takashi
Hi Takashi,
Thanks for your suggestions. Based on your advice on dB levels, I set the PCM and Master channels to 0dB gain, and maxed the levels on the Center, LFE, and Surround channels. The Wave* channels were set to 0 since I was playing surround and not stereo sound.
Playing the same 6-channel sine wave again, I was able to obtain the following, more evenly matched, results:
Front channels: 0.64V peak to peak Rear channels: 0.68V peak to peak Center and subwoofer: 0.48V peak to peak
The front and rear channel output voltages were more evenly matched, but the center/subwoofer channel shows a large difference from the other channels. For comparison, the results I obtained in Windows using the Creative SB Live drivers are:
Front channels: 0.72V peak to peak Rear channels: 0.68V peak to peak Center and subwoofer: 0.64V peak to peak
Is there any way to increase output on the center and subwoofer channels in ALSA? I already have the Center and LFE channels set to maximum gain in alsamixer, so any suggestions to further boost the output are most certainly welcome. :)
Thanks in advance.
At Wed, 20 Jun 2007 17:12:39 +0800, ChernYue Kwok wrote:
On Tuesday 19 June 2007 18:59:01 Takashi Iwai wrote:
At Mon, 18 Jun 2007 17:37:46 +0800,
ChernYue Kwok wrote:
Hello,
I am using an SBLive! 5.1 sound card (emu10k1 chipset) with 6 channel output. Due to the nature of my work, I need to be able to play sound through all 6 channels at the same output level to an amplifier.
Using Linux and the emu10k1 ALSA driver, I measured output voltage levels on an oscilloscope while playing a sine wave on all 6 channels, and I got three different output voltage amplitudes for the front, rear and center/subwoofer channels. Repeating the same test with the same card on WIndows using the Creative SBLive drivers from their website, I am able to get the same output voltage amplitude on all 6 channels. For both tests, all output levels in the relevant mixers were set to their maximum levels.
I would like to know if this output normalizing 'feature' of the SBLive Windows driver can be found in the emu10k1 ALSA driver, or in any other ALSA driver. Failing that, is there any other solution to set output levels in the driver, or am I doomed to twiddle in alsamixer to get the output levels that I want?
Did you check the dB level appearing in mixer? The recent version of ALSA shows dB level in alsamixer and amixer. Note that the "Master" and "PCM" controls are applied only for front channels. So, set them to 0dB and control the volume via Wave* digital mixers.
Takashi
Hi Takashi,
Thanks for your suggestions. Based on your advice on dB levels, I set the PCM and Master channels to 0dB gain, and maxed the levels on the Center, LFE, and Surround channels. The Wave* channels were set to 0 since I was playing surround and not stereo sound.
Playing the same 6-channel sine wave again, I was able to obtain the following, more evenly matched, results:
Front channels: 0.64V peak to peak Rear channels: 0.68V peak to peak Center and subwoofer: 0.48V peak to peak
The front and rear channel output voltages were more evenly matched, but the center/subwoofer channel shows a large difference from the other channels. For comparison, the results I obtained in Windows using the Creative SB Live drivers are:
Front channels: 0.72V peak to peak Rear channels: 0.68V peak to peak Center and subwoofer: 0.64V peak to peak
Is there any way to increase output on the center and subwoofer channels in ALSA? I already have the Center and LFE channels set to maximum gain in alsamixer, so any suggestions to further boost the output are most certainly welcome. :)
Hm, this might have something to do with the signal routing in emu10k1 DSP code. But I don't see obvious difference from other channels at a quick glance of the code (emufx.c)...
Takashi
participants (2)
-
ChernYue Kwok -
Takashi Iwai