From mboxrd@z Thu Jan 1 00:00:00 1970 From: Raymond Yau Subject: Re: Verifying mixer dB data/Invalid dB data from USB cards, especially Aureon 5.1 MkII Date: Sat, 20 Mar 2010 15:58:03 +0800 Message-ID: <4f3252891003200058t2dd77c8an581382eb298a2ccf@mail.gmail.com> References: <4B7A5268.5050704@ladisch.de> <20100216144047.GB10586@sirena.org.uk> <20100216154015.GA612@tango.0pointer.de> <20100216210703.GA18109@tango.0pointer.de> <20100216223938.GA23623@sirena.org.uk> <20100216224212.GA1486@tango.0pointer.de> <20100216233825.GB23623@sirena.org.uk> <20100216235658.GA6766@tango.0pointer.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pw0-f51.google.com (mail-pw0-f51.google.com [209.85.160.51]) by alsa0.perex.cz (Postfix) with ESMTP id 4DA7610380C for ; Sat, 20 Mar 2010 08:58:06 +0100 (CET) Received: by pwj7 with SMTP id 7so2584983pwj.38 for ; Sat, 20 Mar 2010 00:58:04 -0700 (PDT) In-Reply-To: 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: ALSA Development Mailing List List-Id: alsa-devel@alsa-project.org 2010/2/17 James Courtier-Dutton > On 16 February 2010 23:56, Lennart Poettering wrote: > > > > The reason I was asking how Jaroslav chose the 0dB position for his > > measurements was purely because I wanted to do my own measurements for > > that Aureon card. The dbmeasure tool I wrote for stuff like that puts > > 0dB at max amplification, however Jaroslav didn't, so I was wondering > > how he chose 0dB then. > > > > Lennart > > > > I think the digital side is clear. So I will not go into that. > The problem is at the digital side , The range between -inf dB and -48dB / -96dB software atten is lost during the conversion of the floating format format to S16_LE or S32_LE ( native format supported by hardware driver ) i.e. the bottom part of the pulseaudio volume control cannot be used