Jan, No offense taken at all. I'am aware of the Qc,Qt,Fs figures. The optimum way to get these figures for a given speaker pair (For Matching) would be to take an actual impedance reading over a range of freqs and then calculate from the graph produced. There is quite a bit of variance amoung speakers, even if the same model. Steve. -----Original Message----- From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of SkinTech Sent: Tuesday, September 25, 2001 7:32 AM To: PICLIST@MITVMA.MIT.EDU Subject: Re: Has this been done before? Speaker testing Steve, No comment on the pic part of your project, but are you sure you want to calculate box size from the freq/impedance data? Are you aware that what you need to measure are things like Qc, Qt, Fs etc which is done at specific frequency points. No offense meant! Jan Didden ----- Original Message ----- From: "Kasm Consulting And Electronic Repairs" To: Sent: Tuesday, September 25, 2001 4:28 AM Subject: Has this been done before? Speaker testing > Hello All, > > I have a project that I want to do in a pic but > want to make sure it hasn't been done before. > I really hate re-inventing the wheel. > > Anyway, > > What the circuit will do is have a speaker connected > in a test setup and pass a range of frequencies to the > speaker testing the impedance at each frequency. I would > like to have the pic connected to a computer running > a basic program for graphing the results. The results will > later be used to calculate the enclosure size for the speaker. > > Questions > > I know I can use a pic with an A/D for measuring a voltage > but how would you have a pic generate a frequency? > > The frequencies needed are in the audio range from 1hz to about > 20khz. > > If it hasn't been done already I have a schematic of the manual > test setup using a freq generator and dvm to do the test manually. > I could scan and send the schematic if anyone is interested. > > > > Any help would be great, > Steve > mailto://kcer@home.com > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.