WM-61A + LSPLab, why so bad? Heelp!

kimschips · 18th June 2006, 11:01 AM

Hello

I have this gear

Panasonic WM-61A mike
Behringer Mic 100 Mike preamplifier.
LoudspeakerLab 3.1
Soundcard: Soundblaster Auidigy 2ZS

I am supplying WM-61 as they wrote in LSPLab help section, with ektra resistors attached and with 9V dc.

When i try to measure different (bought) loudspeakers, the frequence responce is falling above 2Khz and ends with -15dB at 20Khz!!

Can anybody help me with a little setup guide or good advice for using WM-61A with loudspeakerLab?

And why does the Creatives "mixer" turn off Line input every time you press play in LspLab??

Kim

Gcollier · 18th June 2006, 03:46 PM

You might want to consider using a mic preamp like the one by Eric Wallin. I have built this uint and it works very nicely with LspLab. Also have you selected your mixer under the settings tab in LspLab?

G.

Boris_valkov · 18th June 2006, 04:38 PM

I suppose you are using pink noise as a test signal

Either use a loopback cable from output directly to input to correct for this or switch to white noise.

Cheers!

kimschips · 18th June 2006, 05:42 PM

Hey

Thanks both.

Yes i am using white noise 20-20Khz

Have you calibrated your microphones and how?

Any other thing to remember to set in lspLab?

Kim

Boris_valkov · 18th June 2006, 07:42 PM

So by using white noise rather than pink i guess you now get flat frequency response?

I haven't calibrated my microphone. I use a behringer ECM8000 and I am quite pleased with the results. A few weeks ago i gave the panasonic capsules a go too and they seem very good as well.

As for LSPlab i'd suggest using more pre avarages and the dual channel FFT is a very useful feature to compensate for soundcard frequency response.

Anyway give us some more information. What is your measurement setup?

kimschips · 19th June 2006, 05:03 AM

Hello

I have have only tried white noise until now.

Maybe your right if I try to start with a loop cable and see if something is wrong, I mean if the sound or something else is destroying the frequency liniarity!

May I can try to calibarte the mike by using a loop cable first instaed off a real calibrated mike if you can follow me?

What do you mean by the measurement setup?

What settings I use in my program?

Kim

kimschips · 28th July 2006, 09:31 PM

Hello ALL

I can see now that I was so confused last time!!

The reason why I got so bad measurement responce, were because I have marked Dual FTT and not used a split cable back to soundcard, and thereby it compared the measured signal with "nothing"!!

Have until widere turned Dual Channel Ftt off and I can measure up to 18Khz! (Tweeter is Scanspeak 9700 goes straigt to 30Khz)
Using the window " ½ EXT. Cosine Bell"

Have also found out how to prevent muting Line input when pushing "play" in LSPlab, ( Measurement settings-> Advanced)
Another measured same tweeter in same loudspeaker box up to 30Khz same soundcard too, but used a ECM8000 instead.

Can ECM8000 mike measure higher than WM-61A?

What settings in the program should I look after?

What measurement "window" are you guys using?

Thanks for all!

Kim

18th June 2006, 11:01 AM	#1
kimschips diyAudio Member Join Date: Dec 2004 Location: Denmark	WM-61A + LSPLab, why so bad? Heelp! Hello I have this gear Panasonic WM-61A mike Behringer Mic 100 Mike preamplifier. LoudspeakerLab 3.1 Soundcard: Soundblaster Auidigy 2ZS I am supplying WM-61 as they wrote in LSPLab help section, with ektra resistors attached and with 9V dc. When i try to measure different (bought) loudspeakers, the frequence responce is falling above 2Khz and ends with -15dB at 20Khz!! Can anybody help me with a little setup guide or good advice for using WM-61A with loudspeakerLab? And why does the Creatives "mixer" turn off Line input every time you press play in LspLab?? Kim

18th June 2006, 03:46 PM	#2
Gcollier diyAudio Member Join Date: Mar 2003 Location: Windsor	You might want to consider using a mic preamp like the one by Eric Wallin. I have built this uint and it works very nicely with LspLab. Also have you selected your mixer under the settings tab in LspLab? G. __________________ If you take something apart and put it back together again enough times, eventually you will have two of them.

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18th June 2006, 04:38 PM	#3
Boris_valkov diyAudio Member Join Date: Sep 2005	I suppose you are using pink noise as a test signal Either use a loopback cable from output directly to input to correct for this or switch to white noise. Cheers!

18th June 2006, 05:42 PM	#4
kimschips diyAudio Member Join Date: Dec 2004 Location: Denmark	Hey Thanks both. Yes i am using white noise 20-20Khz Have you calibrated your microphones and how? Any other thing to remember to set in lspLab? Kim

18th June 2006, 07:42 PM	#5
Boris_valkov diyAudio Member Join Date: Sep 2005	So by using white noise rather than pink i guess you now get flat frequency response? I haven't calibrated my microphone. I use a behringer ECM8000 and I am quite pleased with the results. A few weeks ago i gave the panasonic capsules a go too and they seem very good as well. As for LSPlab i'd suggest using more pre avarages and the dual channel FFT is a very useful feature to compensate for soundcard frequency response. Anyway give us some more information. What is your measurement setup?

19th June 2006, 05:03 AM	#6
kimschips diyAudio Member Join Date: Dec 2004 Location: Denmark	Hello I have have only tried white noise until now. Maybe your right if I try to start with a loop cable and see if something is wrong, I mean if the sound or something else is destroying the frequency liniarity! May I can try to calibarte the mike by using a loop cable first instaed off a real calibrated mike if you can follow me? What do you mean by the measurement setup? What settings I use in my program? Kim

28th July 2006, 09:31 PM	#7
kimschips diyAudio Member Join Date: Dec 2004 Location: Denmark	Hello ALL I can see now that I was so confused last time!! The reason why I got so bad measurement responce, were because I have marked Dual FTT and not used a split cable back to soundcard, and thereby it compared the measured signal with "nothing"!! Have until widere turned Dual Channel Ftt off and I can measure up to 18Khz! (Tweeter is Scanspeak 9700 goes straigt to 30Khz) Using the window " ½ EXT. Cosine Bell" Have also found out how to prevent muting Line input when pushing "play" in LSPlab, ( Measurement settings-> Advanced) Another measured same tweeter in same loudspeaker box up to 30Khz same soundcard too, but used a ECM8000 instead. Can ECM8000 mike measure higher than WM-61A? What settings in the program should I look after? What measurement "window" are you guys using? Thanks for all! Kim

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