Very basic questions regarding LSPCad and measurements - diyAudio
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Old 27th January 2006, 04:38 PM   #1
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Join Date: Apr 2005
Location: Mexico City
Default Very basic questions regarding LSPCad and measurements

Hi all!

I've been using LSPCad for some time in two projects. One of them ended up sounding OK, the other one was a failure (and it was a basic full-range speaker!).

I decided to get Vance Dickason's Cookbook. Now I understand plenty of things I did wrong, and will tackle the second project again.

Still, I have two very basic questions regarding LSPCad...

1) I know I have to measure the tweeter's response at 1 M; then the woofer's response at 1 M; then both drivers' response at 1 M. My question is, where should I place the mic when taking those measurements? Along the tweeter's axis? Midway between tweeter and woofer? Somewhere else? Also, when I have every measurement, should I play with the Z-axis until the individual measurements add up exactly like their combined response?

2) I have already measured the impedance of the drivers using the Dayton Woofer Tester II (Woofers). Can I directly measure the tweeter's impedance, or should I add a cap before the tweeter? Also, should I measure the impedance while inside the enclosure, or in free air?

I know these are very basic questions, but I've been looking, and I can't find the answers!
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Old 28th January 2006, 09:15 AM   #2
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Join Date: Dec 2004
Location: Århus
Default Re: Very basic questions regarding LSPCad and measurements

Quote:
Originally posted by fjhuerta
Hi all!

I've been using LSPCad for some time in two projects. One of them ended up sounding OK, the other one was a failure (and it was a basic full-range speaker!).

I decided to get Vance Dickason's Cookbook. Now I understand plenty of things I did wrong, and will tackle the second project again.

Still, I have two very basic questions regarding LSPCad...

1) I know I have to measure the tweeter's response at 1 M; then the woofer's response at 1 M; then both drivers' response at 1 M. My question is, where should I place the mic when taking those measurements? Along the tweeter's axis? Midway between tweeter and woofer? Somewhere else?
The tweeters axis if it is the listening hight.
Also, when I have every measurement, should I play with the Z-axis until the individual measurements add up exactly like their combined response?
Yes, I always take two kontrol measurements, one with drivers in phase and one with drivers out of phase. The microphone should be at the exact same place as the single driver measerements.

2) I have already measured the impedance of the drivers using the Dayton Woofer Tester II (Woofers). Can I directly measure the tweeter's impedance, or should I add a cap before the tweeter?
If its a normal dome tweeter and the amp dosnt have dc out you can connect direct but disconnect before switching on and off.
Also, should I measure the impedance while inside the enclosure, or in free air?
In cabinet.

I know these are very basic questions, but I've been looking, and I can't find the answers!
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Old 28th January 2006, 03:41 PM   #3
diyAudio Member
 
Join Date: Apr 2005
Location: Mexico City
Thanks a lot! No wonder my first designs were so bad... I was doing everything wrong

I'll go back and do it all over again... the right way.

Thanks again!
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