From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eduard Bloch Subject: Re: [snd-intel8x0] distortion on PCM volume >> 50% Date: Sun, 30 Nov 2003 12:36:24 +0100 Sender: alsa-devel-admin@lists.sourceforge.net Message-ID: <20031130113624.GA1829@zombie.inka.de> References: <20031130100343.GA12681@zombie.inka.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Errors-To: alsa-devel-admin@lists.sourceforge.net List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: To: Jaroslav Kysela Cc: alsa-devel@lists.sourceforge.net List-Id: alsa-devel@alsa-project.org Moin Jaroslav! Jaroslav Kysela schrieb am Sunday, den 30. November 2003: > > I have some problems with a ac97 based sound card (Notebook built-in) > > where the kernel driver works fine (except of not beeing able to > > resample on-the-fly). > > > > When I set the PCM mixer volume to more then 50%, I hear few sound > > fragments. If I go over 75% I hear them all the time and on 100% PCM, > > the sound is full of scratching fragments. You can get an example > > catched with microphone on > > http://sites.inka.de/W1752/alsa-distortion.ogg and the original is on > > www.vorbis.com/music/Mists_of_Time-4T.ogg . First I suspected a speaker > > problem since it sounds very similar to overloud speaker setting, but it > > is not! > > Are you sure that you don't have enable any other analog input? My > notebook has very noisy build-in microphone for example. No, my microphone is not built-in and not attached, the mixer is set to 0. > Also note that if you have value over 70% with most of AC'97 controls, the > analog gain is applied to the signal (thus you can really overdrive the > output or input). After almost an hour playing different stuff with different settings with the ALSA, Linux-Kernel and Windows driver, I have the following assumption: both, Kernel driver and Windows driver are cheating! They do not present the Bass/Treble boost controls and the PCM volume at 75% in ALSA is quite comparable with 100% PCM volume with other drivers, having quite comparable quality when Bass/Treble boost were set to 0. So what I wish for the future version of ALSA drivers: a module option to set the real mixer scale for PCM (or other sources) between 0 and X percent while the visible scale is between 0 and 100 percent and recalculated internaly to 0..X%. But back to the second problem, I created a live example on http://sites.inka.de/W1752/b.ogg - you can hear the fragments on time points 0:35 and 1:31. MfG, Eduard. -- Wer gar zu viel bedenkt, wird wenig leisten. ------------------------------------------------------- This SF.net email is sponsored by: SF.net Giveback Program. Does SourceForge.net help you be more productive? Does it help you create better code? SHARE THE LOVE, and help us help YOU! Click Here: http://sourceforge.net/donate/