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Old 16th January 2013, 01:00 PM   #11
diyAudio Member
Join Date: Jul 2012
Location: Verona
how can I analyze the acoustic summation/results with LTspice?
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Old 16th January 2013, 01:37 PM   #12
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Join Date: May 2002
Location: Switzerland
have you moved the phase EQ to the input before split to both sections of the XO yet?
It is not a phase Equaliser he is trying to make. It is a delay line consisting of a chain of allpass filters.


I guess you are trying to delay because of the driver offset, aren't you ? In this case you will run into false results when you simply add the traces in a simulation. You would of course have to delay the woofer's output also by 140 us in order to have the same delays for both. In most simulators you could use the transmission line model for this purpose. And this is just the beginning: If you don't try to model the driver respones as well you will not get anything reasonably close to real-life.



Last edited by phase_accurate; 16th January 2013 at 01:46 PM.
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Old 16th January 2013, 03:46 PM   #13
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Join Date: Jul 2012
Location: Verona
so what I have understood is that in my project I have to leave the bass as it is and delay the treble, and because I cannot have a good simulation I have to make sure that the simulation of only the allpass filters give me the required delay with a flat gain of 0dB on the audio bandwidth. is it right?
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Old 16th January 2013, 06:26 PM   #14
Davey is offline Davey  United States
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Join Date: Dec 2001
Location: Bremerton, WA.
The all-pass filter should yield flat amplitude gain regardless....otherwise it's not properly named.

In order to determine the required delay for the all-pass section you need to perform acoustic measurements on your system to characterize how far "ahead" of your woofer the tweeter is.

Simulations are fine to a point, but eventually you have to incorporate real-world data into a speaker design.


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Old 16th January 2013, 07:17 PM   #15
jcx is offline jcx  United States
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post the .asc - it is an allowed attachment file type - I'm not about to hand enter your cirucit to debug it for you - especially when you won't even cut and rewire one connection
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