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: Mon, 8 Mar 2010 17:06:57 +0800 Message-ID: <4f3252891003080106j3d3e74f3h6b3a98ae9f471260@mail.gmail.com> References: <20100215192451.GA17938@tango.0pointer.de> <4B7A5268.5050704@ladisch.de> <20100216142633.GA25489@tango.0pointer.de> <4f3252891002161930i25d411ap6c0b9ad8977f336e@mail.gmail.com> <20100217151941.GB4181@tango.0pointer.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-gy0-f179.google.com (mail-gy0-f179.google.com [209.85.160.179]) by alsa0.perex.cz (Postfix) with ESMTP id 92A6C103802 for ; Mon, 8 Mar 2010 10:06:59 +0100 (CET) Received: by gyg13 with SMTP id 13so262562gyg.38 for ; Mon, 08 Mar 2010 01:06:57 -0800 (PST) In-Reply-To: <20100217151941.GB4181@tango.0pointer.de> 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-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org 2010/2/17 Lennart Poettering > On Wed, 17.02.10 11:30, Raymond Yau (superquad.vortex2@gmail.com) wrote: > > > > > 2010/2/16 Lennart Poettering > > > > > On Tue, 16.02.10 09:08, Clemens Ladisch (clemens@ladisch.de) wrote: > > > > > > > > > > > > if the program use a format FLOAT_LE which is not supported by the > hardware > > and need to use plughw , you have already added error ( resampling and > > format conversion ) to the result > > That numeric noise is neglible in contrast to the big (20dB or so?) > discrepancy I am seeing here. > > Lennart > For HDA , some codec can playback/record in 16 , 20, 24 or 32 bits , if you are using non-native format , I think there should be some practical difference when HDA codec use 16 , 24, or 32 bits for running your test