Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_MED,SPF_PASS,T_DKIM_INVALID autolearn=ham autolearn_force=no version=3.4.0 X-Spam-DCC: EATSERVER: mailn 1166; Body=2 Fuz1=2 Fuz2=2 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by lipkowski.org (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id v69HbvU0003960 for ; Sun, 9 Jul 2017 19:37:59 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1dUG5D-0007rk-OG for rs_out_1@blacksheep.org; Sun, 09 Jul 2017 18:33:23 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1dUG5D-0007rb-19 for rsgb_lf_group@blacksheep.org; Sun, 09 Jul 2017 18:33:23 +0100 Received: from porthos.netcom.co.uk ([217.72.171.73]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1dUG5A-00019N-9U for rsgb_lf_group@blacksheep.org; Sun, 09 Jul 2017 18:33:21 +0100 X-DKIM-Result: Domain=abelian.org Result=Signature OK DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=abelian.org ; s=default; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:From:References:To:Subject:Sender:Reply-To:Cc: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=D4QZRVC2VjUABuSaqq78Oh4KcQ6eRxzvAKgHp3RGNvA=; b=BRXfEyQV1w2XNdCYyeKzGHUDBW /0X8yH8Ii9U1Uat9SdThSvnvo40BykfeG2DWBYP4cnLZYxCN8xks1cUfYIml2f820z3hAf+7Qrz5U pXl/ABC5cXTaGISAYGvopwfyh1EuCu3xSbJSGI+UaHWgje2e1cVHi3XsVE+nUgP3MKtI=; Received: from i-194-106-52-83.freedom2surf.net ([194.106.52.83]:41464 helo=pn.abelian.org) by porthos.netcom.co.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1dUG58-0007Qn-8z for rsgb_lf_group@blacksheep.org; Sun, 09 Jul 2017 18:33:18 +0100 Received: from [127.0.0.1] (localhost [127.0.0.1]) by pn.abelian.org (Postfix) with ESMTP id AC167400923 for ; Sun, 9 Jul 2017 17:33:17 +0000 (UTC) To: rsgb_lf_group@blacksheep.org References: <15d26b31fb5-c01-17d82@webjas-vab174.srv.aolmail.net> <59621195.4080109@posteo.de> From: Paul Nicholson Message-ID: <4eea559e-7e23-f390-67db-c43f68d103db@abelian.org> Date: Sun, 9 Jul 2017 17:33:17 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <59621195.4080109@posteo.de> X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - porthos.netcom.co.uk X-AntiAbuse: Original Domain - blacksheep.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - abelian.org X-Get-Message-Sender-Via: porthos.netcom.co.uk: authenticated_id: catchall@abelian.org X-Authenticated-Sender: porthos.netcom.co.uk: catchall@abelian.org X-Scan-Signature: 2e2f7cbbe9f38dd7bf3fac4fc012e6fc Subject: Re: LF: Octo-soundcard for the Raspi, another question Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Scanned-By: MIMEDefang 2.75 Status: RO X-Status: X-Keywords: X-UID: 12206 Let's try an experiment. Capture a short sample 6 channels 96k/sec int2 format, directly into a file. No input, all inputs open circuit. Max alsamixer gain. Hopefully capture where at least one channel is showing a long 'event', eg 100mS where the noise drops. Maybe it doesn't appear when there is no input tone. If it does, we can measure the noise during the event and compare with my Octo. We can work out whether or not the noise level during the event is the 'correct' one. vtcard -d hw:0,0 -b32 -c8 -r96000 -u -v test.vt,i2 -u turns off timestamping. Just ctrl-C to stop it after 20 seconds or so then look at it with vtsgram to see if any of the channels has a good noise event. -- Paul Nicholson --