From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rene Herman Subject: Re: What does 0dB refer to? (Logitech USB Speakers) Date: Tue, 10 Jun 2008 01:37:05 +0200 Message-ID: <484DBEA1.4060409@keyaccess.nl> References: <20080411204610.GA32413@tango.0pointer.de> <20080414172839.GA26513@tango.0pointer.de> <4803C78A.3020109@superbug.co.uk> <200804150552.13578.faber@faberman.de> <20080415131203.GA2818@localhost> <4804BCB8.9060707@keyaccess.nl> <48060D2F.2000701@keyaccess.nl> <480618F3.40707@keyaccess.nl> <48061D1F.6060809@keyaccess.nl> <4807B569.6000008@superbug.co.uk> <4807C17F.8030603@keyaccess.nl> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from smtpq1.tilbu1.nb.home.nl (smtpq1.tilbu1.nb.home.nl [213.51.146.200]) by alsa0.perex.cz (Postfix) with ESMTP id BE5A624A22 for ; Tue, 10 Jun 2008 01:37:03 +0200 (CEST) In-Reply-To: <4807C17F.8030603@keyaccess.nl> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: alsa-devel-bounces@alsa-project.org Errors-To: alsa-devel-bounces@alsa-project.org To: James Courtier-Dutton Cc: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org On 17-04-08 23:30, Rene Herman wrote: >>>>> James, I believe you are the emu10k1 person? Data: >>>>> >>>>> TerraTec DMX = ESS Canyon3D (ES1970MS-3D) + Sigmatel STAC9704T >>>>> >>>>> Creative Audigy 2 (SB0240) = Creative CA0102-ICT + Sigmatel >>>>> STAC9721T (+ Crystal CS4382-KQ which seems to provide digital >>>>> attenuation as well) >>>>> >>>>> At 0 dB master the Audigy 2 is much louder than the DMX is and >>>>> audibly distorts. Judging by hearing, keeping the master at -16 dB >>>>> (60 in the integer scale) gets things about the same. Was that >>>>> scale provided by datasheet or just guessed? Especially the >>>>> distortion would seem to indicate that something is actually doing >>>>> analogue amplification at the 0 dB ALSA setting... >>>> >>>> Expanding, with the 'Line' control at 0 dB (74 integer) and 'Analog >>>> Mix' at 0 dB (100 integer) everything does sound right with both >>>> 'Master Capture' and 'Master' at full, and too faint with 'Master' >>>> at -16 dB. I guess this indicates that it's something at the DSP >>>> side only? (sort of loosing my way in this bewildering array of >>>> controls so if I need to be guided to possibly say sensible things >>>> -- please do) >>> >>> When I do actually capture, -16 dB master is again the correct >>> setting when playing back (with everything else still set to 0 dB as >>> described above). It's then equally load as when directly monitored >>> during recording. I expect then the Master dB scale needs to be >>> adjusted down? If yes, I'll try to make very, very sure that -16 dB >>> now is the correct new 0 dB. >> >> Can we narrow this down a bit please. >> Run speaker-test -c2 -twav >> Do the test to each sound card with alsamixer set to 0dB for most >> controls accept the master, and leave the master at a sensible setting >> for your setup so that you can hear sound at a sensible level >> With the same dB values on the Andigy 2 and DMX, do you get the same >> loudness of sound output to the speakers? > > Very much not. Sorry, it seems the report (unsnipped above) got a little > confusing due to the followups but with everything at 0 dB on both DMX > and Audigy 2, the Audigy 2 is much louder and distorts. > > DMX has 'PCM' -34.5 --> +12 dB and 'Master' -46.5 --> 0 dB. I always > keep both at 0 dB for a good, comfortable level (adjusted further > externally). > > Audigy 2 'Front' and 'Wave' are both at 0 dB (max) (everything default > in fact) and with 'Master' at 0 dB, it's much louder then the DMX. > Setting 'Master' to -16 dB (60) gets things the same. > >> I would like to find out if the problem is in the playback path, or >> the capture path. > > Playback I'd say and I personally consider DMX right here, due to the > distortion from the Audigy. > > Only introduced capture into the story above as "additional evidence" > where I could do a a comparison using only the Audigy itself and not the > DMX: with everything at 0 dB in the capture direction, a captured file > needs to be played back at -16 dB 'Master' to be equally loud to what I > hear _during_ capturing as well ("hear" from 'Analog Mix' at 0 dB). So I > get the feeling it's a simple matter of transposing 0 dB on the Master > scale for the Audigy (ie, new 0 dB is old -16 dB). > > I should have another emu10k1 driven card here somewhere. Is it useful > if I try to dig it up and see if the story's the same on it? Was this a useful report? Rene.