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Sender: "piclist-bounces@mit.edu" Date: Wed, 18 Mar 2020 22:02:18 -0700 Subject: [EE] Measuring speaker impedance Thread-Topic: [EE] Measuring speaker impedance Thread-Index: AdX9rN6hiAzUflbWSbWI1B1wOYdBCg== Message-ID: <5E72FCDA.8020300@narwani.org> List-Help: List-Subscribe: , List-Unsubscribe: , Reply-To: Microcontroller discussion list - Public. Accept-Language: en-US X-MS-Exchange-Organization-AuthAs: Anonymous X-MS-Exchange-Organization-AuthSource: TS500.efplus4.local X-MS-Has-Attach: X-Auto-Response-Suppress: All X-MS-Exchange-Organization-SenderIdResult: Pass X-MS-Exchange-Organization-PRD: mit.edu X-MS-TNEF-Correlator: received-spf: None (protection.outlook.com: narwani.org does not designate permitted sender hosts) dkim-signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=narwani.org ; s=default; h=Content-Transfer-Encoding:Content-Type:MIME-Version:Date: Message-ID:Subject:From:To:Reply-To:Sender:Cc:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: In-Reply-To:References:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=ZovWTOcdUxQjdhAucMRgPy4HrSKFIgX8zaRJd7BHi+s=; b=GJjx2WbIy6WBORXexofBuqxN9O RzKnx0Bh/PA7MGaaSjjMJQ9HRd6nEEsh0xNRNIimV8FVWlPdbF7T6wS2uuP9pqnmrjY2gIsXtUA2c GV4pGtm/NplZASCOTaMvSBRvqGZzhhtOWIZX1Ck5qWTpwZ45RVCIGnfkkasJM3y1SqROcZsYSs1Fd AqKHAsQsPpCsKsA69qPFuP6JiQF/rumDkv3zQ3c++z1hxGLMilBxpfz1r0TEEysQ1P5x6pfU9jN7V dwn6KBHnhyJSdVPdY7MCl9NNtH8qre8D8zZLW6S/e1yVdAn7VLwnQ1W+xs9+rDuYEWDaWW0VgePH9 kEtp+9Uw==; authentication-results: spf=none (sender IP is 68.65.123.244) smtp.mailfrom=narwani.org; mit.edu; dkim=pass (signature was verified) header.d=narwani.org;mit.edu; dmarc=bestguesspass action=none header.from=narwani.org;compauth=pass reason=109 user-agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.0 errors-to: piclist-bounces@mit.edu list-id: "Microcontroller discussion list - Public." list-post: x-beenthere: piclist@mit.edu x-mailman-version: 2.1.6 x-source-args: x-source-dir: x-antiabuse: Sender Address Domain - narwani.org x-source: x-authenticated-sender: premium47.web-hosting.com: ca4@narwani.org x-topics: [EE] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Hi, I'm working on a project for a friend, which will measure speaker=20 impedance over a given frequency range. I'm thinking I'd use a function=20 generator sweeping across frequency range, then measure current (prob=20 with a clamp sensor) and voltage across the speaker and do the math from=20 there. No prob so far. But can how about doing this dynamically? IE: play music and=20 dynamically figure out speaker impedance from there. He believes=20 commercial devices do this. So far, all I can think of is measuring the=20 voltage and current as before, but dynamically FFT-ing both and=20 (rapidly) doing the math from there. Does this seem workable? Cheers, -Neil. --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .