| Help on making driver measurements, please? [message #41749] |
Sun, 29 June 2003 16:03  |
wunhuanglo
Messages: 912
Registered: May 2009
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Illuminati (2nd Degree) |
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I want to be able to measure "Fs" (resonance) and Qts for drivers under various conditions; horn loaded, reflex loaded, free air, etc... I have to accomodate a number of restrictions: 1. I'm an idiot
2. I'm relatively poor
3. I'm an idiot. I:
1. have a PC
2. can buy decent soundcard
3. have a BK DVM Can anyone suggest how I might equip myself to make these measurements? TIA
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| Re: Help on making driver measurements, please? [message #41751 is a reply to message #41749] |
Sun, 29 June 2003 19:02  |
Bill Martinelli
Messages: 677
Registered: May 2009
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Illuminati (1st Degree) |
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For the fastest and most easy rout I would suggest buying the woofer tester contraption from parts express. This leaves us at problem 2. It cost 200. For the cheaper rout you can download the program "speaker workshop" for free and use it with your pc. I believe for your purpose a generic duplex sound card will be just fine. This leaves at problem 1 and possible problem 3. As an Aside, I really feel that this is only a problem 1 type issue and thus you would not enter the rehlm of problem 3. Theres a link to speaker workshop on my website in the links area if you havnt come across this program before.
Bill
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| Re: Help on measurements, Thanks Bill [message #41755 is a reply to message #41751] |
Mon, 30 June 2003 15:40 |
wunhuanglo
Messages: 912
Registered: May 2009
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Illuminati (2nd Degree) |
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Actually my first move would have been the PE box, except that they discontinued it some time ago and there was a great deal of flak that it didn't work (I have no idea if it's true or not). On to Speaker Workshop - Thanks again!
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| Re: Help on measurements, Thanks Bill [message #41762 is a reply to message #41755] |
Tue, 01 July 2003 05:31 |
Bill Martinelli
Messages: 677
Registered: May 2009
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Illuminati (1st Degree) |
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Disapointing that PE discontinued that tester. I was hoping to pick one up at some point. If it worked or not would be very important!
Eric Walin has a website with test fixtures and pointers for Speaker Workshop. I'm still faced with problem 1 getting speaker workshop to function! Cant ever get past the calibration part. We need a interactive webcam webcast tutorial for a small group on how to set this program up. Bill
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| Re: Woofer Tester [message #41777 is a reply to message #41762] |
Tue, 01 July 2003 19:05 |
AstroSonic
Messages: 58
Registered: May 2009
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Baron |
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I have been using the Woofer Tester for about 3 years with no problems. I purchased one after checking the two reviews in Speaker Builder: David Weems in Issue 5/97 and Vance Dickason in issue 5/94. Both reviews were quite favorable and turned up no significant flaws. Both considered it to be an excellent buy at $399 in 1994 and $249 in 1997. After several years of measuring T-S parameters manually the Woofer Tester is a real joy to use. I have seen a couple references to its not working here on this forum and wonder where it started. Perhaps somebody can clarify. In any case, I have found it to be easy to use and reliable. I have used it with Windows 95 and 98, but had some difficulty with 2000 (then again, so did the computer - ended up taking it off). Too bad if it is really discontinued. One would certainly be worth picking up used. Regards, AstroSonic
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| Re: Help on measurements, Thanks Bill [message #41791 is a reply to message #41790] |
Wed, 02 July 2003 17:50 |
Bill Martinelli
Messages: 677
Registered: May 2009
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Illuminati (1st Degree) |
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I have not put together one of the test jigs so if this is an important thing to have that would explain a lot. From reading through the directions It seemed that you could use the software with out a test jig. I try to follow the directions to calibrate the software and after connecting a few resisters to the in and out of the sound card as described. It does not measure a correct value of a known resister after calibration. thats about the jist of the problem. Bill
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| Re: Help on measurements, Thanks Bill [message #41792 is a reply to message #41791] |
Wed, 02 July 2003 19:12 |
ToFo
Messages: 219
Registered: May 2009
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Master |
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Bill,
in some of the speaker workshop forum post and links I noticed that some who could not get it to work at all had little trouble after the jig was made. Something about cable and aligator clips/crimps playing havoc with calibration values(sensitive i guess). there is also a modified jig that is somewhere on the SW page, supposed to be more flexible or...(it's not hard to find) The article I found most informative is below. Since you mentioned SW maybe you have seen this, but just in case.Thomas F. P.S. I am making a jig and trying to get SW going very soon, so I will let you know how it goes, or any tricks I learn if I do well.
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| Re: Help on measurements, Thanks Bill [message #41793 is a reply to message #41791] |
Thu, 03 July 2003 05:40 |
JS
Messages: 4
Registered: May 2009
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Esquire |
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I don't think you have to use the test jig - you just need good connections, as noted. The test jig is just a way of making things a bit easier / neater. Are you measuring a resistor around 8 ohms? The program will have problems measuring values that are too far away from the reference resistor, iirc.
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