From mboxrd@z Thu Jan 1 00:00:00 1970 From: bugtrack@alsa-project.org Subject: [ALSA - driver 0001187]: Gain control for M-Audio Revolution (and other ice1724 cards) needed Date: Sun, 12 Jun 2005 15:51:33 +0200 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from bugtrack.alsa-project.org (gate.perex.cz [82.113.61.162]) by alsa.jcu.cz (ALSA's E-mail Delivery System) with ESMTP id 0312E1D1 for ; Sun, 12 Jun 2005 15:51:33 +0200 (MEST) Sender: alsa-devel-admin@lists.sourceforge.net Errors-To: alsa-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org The following issue has been SUBMITTED. ====================================================================== ====================================================================== Reported By: sst4 Assigned To: ====================================================================== Project: ALSA - driver Issue ID: 1187 Category: PCI - ice1724 Reproducibility: always Severity: feature Priority: normal Status: new Distribution: Mandriva Kernel Version: 2.6.11 ====================================================================== Date Submitted: 06-12-2005 15:51 CEST Last Modified: 06-12-2005 15:51 CEST ====================================================================== Summary: Gain control for M-Audio Revolution (and other ice1724 cards) needed Description: Hello, this is in a sense continuation of https://bugtrack.alsa-project.org/alsa-bug/view.php?id=1164 . Yes, I remember Takashi's statement that the ADC chip on the card does not have gain control, and I checked the ADC specs and it's indeed so. However, this doesn't mean the functionality can not be implemented. I believe it should be implemented for at least two reasons: 1) Windows driver has it; 2) Applications like "Skype" need it to implement AGC (automatic gain control) in software. Regarding 2) - I clearly hear while talking through "Skype" that gain on the other party's side increases (room noise pickup is becoming more and more evident) when the other party makes a pause in conversation. Regarding 1) - in http://m-audio.com/images/en/manuals/Revo71-Manual-EN.pdf file on page number 14, under "Line and Mic In" one can read: " You can set the INPUT LEVEL of the Line and Mic inputs on the Input/Other tab of th Revolution 7.1 control panel. See the Control Panel section for more details. " (capitalization by me). On page number 22 of the same file, under "Input/Other Tab": " The Input/Other tab controls the INPUT LEVELS and sampling frequency of the Revolution. You don't need to worry about the settings on this page unless you're recording audio with the Revolution. Link Stereo Input Levels - The Input/Other tab controls the INPUT LEVELS and sampling frequency of the Revolution. You don't need to worry about the settings on this page unless you're recording audio with the Revolution. " (capitalization by me). On page number 25 under "Recording": " The Revolution 7.1 includes a pair of audio inputs for recording. You can set the INPUT LEVEL of the inputs by launching the Revolution 7.1 control panel, selecting the Input/Other tab, and changing the level on that screen. If your recording application doesn't see audio from the Revolution's inputs, check that program's audio preferences, check your cable connections, or review the Software Setup chapter for potential problems. Go to the Windows Control panel and open Sounds and Multimedia icon. The Revolution 7.1 features both Line and Mic inputs for the best performance with your input source. The Revolution 7.1 records at sampling rates up to and including 96kHz. " (capitalization by me). The "Input/Other" tab in its non-selected form can be seen on the picture on page 20 - to see it more clearly I had to choose 400% zoom in 'xpdf'. Regarding feasibility. First of all, gain can be changed by multiplying the code by the gain value. If I remember correctly, in ALSA the card outputs audio data in 32 bit format, of the 32 bits only 24 bits are significant because that's what the ADC produces, so we have 8 spare bits, which means 256 times, or about 48dB gain control without even losing precision. General note on priority of implementing the feature. Though I believe the feature is needed, and not only for Revolution 7.1, but also for other ICE1724-based cards, please understand the following: *** I still have no capture with my Revolution 7.1 (issue https://bugtrack.alsa-project.org/alsa-bug/view.php?id=0001096) *** . Since I'm not getting it work, I've been trying to use ALSA utilities ('amixer', 'alsamixer', 'aoss') - "trial and error" approach - to make it work, and have found other problems on the way. Resolution of these other problem, including introduction of gain control, will not solve my main problem - lack of capture. I would appreciate getting an answer to the question in https://bugtrack.alsa-project.org/alsa-bug/view.php?id=1096 : " Maybe my previous question does not contain enough details. Here is the rephrased question: Running 'amixer' with this command line amixer cget numid= , where Mandriva 06-12-05 15:51 sst4 Kernel Version => 2.6.11 ====================================================================== ------------------------------------------------------- This SF.Net email is sponsored by: NEC IT Guy Games. How far can you shotput a projector? How fast can you ride your desk chair down the office luge track? If you want to score the big prize, get to know the little guy. Play to win an NEC 61" plasma display: http://www.necitguy.com/?r=20