measurement on LspLAB

Audist · 29th March 2007, 02:20 AM

Hi guy's.

I make a Near field measurement for the woofer and the tweeter with my first order crossover.

I use with a Calculator for merge a curves.
But I have some problem with the measurement...

If I use with "Average Curves" calculator and select Complex operation, I have some problem in 2140Hz. maybe is where the crossover is cut between the woofer and the tweeter... But if I remove the "V" from the "Complex operation" box, The graph look much better!

Anybody can tell me what is a truth graph?

Thanks for help.

Graph 1: with "Complex operation"

Audist · 29th March 2007, 02:23 AM

uncheck the "Complex operation"

opp · 29th March 2007, 09:38 PM

I'm not familiar with lspLAB, but my guess is that complex means, including phase - the orange curve in "graph1" indicates this. If I'm correct, then don't uncheck "complex operation", the phase information is important. E.g. read the Speaker Workshop manual 2.0 http://www.claudionegro.com/download.html - i know, it's a different software, but there is a lot of general speaker measurement theory.

Svante · 31st March 2007, 06:56 PM

I am not familiar with the software either, but indeed it seems like the "complex" option uses the phase of the signals when making the combined curve, just as in real life.

Both the name on the tick box and what happens indicates that this is the case.

If this is right, I cannot imagine a reason for not having it checked. In fact, I think the checkbox should not be there. The only function it has is to show that the program can do proper (complex) addition of the curves, and to demonstrate how bad (=nonrealistic) it is not to have it.

But maybe I fail to see a good reason right now. Anyone?

4lexander · 31st March 2007, 07:07 PM

hello,

range : -80 up to 20dB ? 100dB in your curve then we can see nothing ...

opp · 31st March 2007, 07:50 PM

Hi

Just to get this right.

All this about check, don't uncheck etc. is a little confusing - phase information is mandatory in speaker design, therefore Graph 1 must be correct.

4lexander - IMO 100 dB gives a good overview, you can always zoom in.

4lexander · 31st March 2007, 08:05 PM

Hello,

But, any speaker will be like linear with 100dB range...

just my remark ...

opp · 31st March 2007, 08:40 PM

Quote:

Originally posted by 4lexander
Hello,

But, any speaker will be like linear with 100dB range...

just my remark ...

4lexander

Agree

- but the resolution of graphs posted by Audist is almost 1dB. Personally I always zoom in on xo points etc, but also use the 100 dB view.

29th March 2007, 09:38 PM	#3
opp diyAudio Member Join Date: Jul 2005 Location: Aros	I'm not familiar with lspLAB, but my guess is that complex means, including phase - the orange curve in "graph1" indicates this. If I'm correct, then don't uncheck "complex operation", the phase information is important. E.g. read the Speaker Workshop manual 2.0 http://www.claudionegro.com/download.html - i know, it's a different software, but there is a lot of general speaker measurement theory. __________________ time flies like an arrow ... and fruit flies like a banana

31st March 2007, 06:56 PM	#4
Svante diyAudio Member Join Date: Feb 2004 Location: Stockholm	I am not familiar with the software either, but indeed it seems like the "complex" option uses the phase of the signals when making the combined curve, just as in real life. Both the name on the tick box and what happens indicates that this is the case. If this is right, I cannot imagine a reason for not having it checked. In fact, I think the checkbox should not be there. The only function it has is to show that the program can do proper (complex) addition of the curves, and to demonstrate how bad (=nonrealistic) it is not to have it. But maybe I fail to see a good reason right now. Anyone? __________________ Simulate loudspeakers: Basta! Simulate the baffle step: The Edge

31st March 2007, 07:50 PM	#6
opp diyAudio Member Join Date: Jul 2005 Location: Aros	Hi Just to get this right. All this about check, don't uncheck etc. is a little confusing - phase information is mandatory in speaker design, therefore Graph 1 must be correct. 4lexander - IMO 100 dB gives a good overview, you can always zoom in. __________________ time flies like an arrow ... and fruit flies like a banana

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31st March 2007, 07:07 PM	#5
4lexander diyAudio Member Join Date: Nov 2005 Location: Strasbourg	hello, range : -80 up to 20dB ? 100dB in your curve then we can see nothing ...

31st March 2007, 08:05 PM	#7
4lexander diyAudio Member Join Date: Nov 2005 Location: Strasbourg	Hello, But, any speaker will be like linear with 100dB range... just my remark ...

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