I have read his very good presentation and I have been asking myself if there are not other variables afecting phase response (I am almost sure I am missing something...). When I model an enclosure I can see phase shift, drivers alone as BP devices induce shifts, op-amps, output transformers, etc. Now I think the spreadsheet asumes all these as linear phase devices, but to my surprise the measured responses he shows very good phase tesponse troughout the freq range.
I would appreciate if someone could help me with my difficulty.
I would appreciate if someone could help me with my difficulty.
Document and Speadsheet (doc, xls): http://freerider.dyndns.org/anlage/LeCleach1.zip
Theory of operation (ppt): http://freerider.dyndns.org/anlage/LeCleach2.zip
🙂/sreten.
Theory of operation (ppt): http://freerider.dyndns.org/anlage/LeCleach2.zip
🙂/sreten.
swak said:
Hi,
As far as I can tell it represents YATFF (yet another theoretical filter
function) and as such it would be your final acoustic target, or put
another way the drivers / enclosures are idealised to be perfect.
🙂/sreten.
Serten, that is what I thought. What has been puzzling me are the very nice MEASURED results he gets with those horn systems (as shown in his presentation).
Hi,
The spectograms seem to be derived from the above impulse response.
The second is certainly well aligned, where it comes from I'm not sure.
🙂/sreten.
The spectograms seem to be derived from the above impulse response.
The second is certainly well aligned, where it comes from I'm not sure.
🙂/sreten.
Hello Swak,
on the document downloadable at:
http://freerider.dyndns.org/anlage/LeCleach.htm
On page 52: this is a pulse response I measured on a two ways system using a Le Cléac'h crossover (the bass enclosure is a bass reflex quasi 2nd order using a low tuning frequency, its response is nearly the one of a closed enclosure, low group delay below 70Hz).
Page 68 of the same document: this is the pulse response measured on the system I brought at ETF2004. THe measurement was done the day before the conference I gave on "phase distortion".
You can see others pulse measurements and curves derived from pulse measurements on the document:
http://www.melaudia.net/zdoc/distorsion_de_phase.pdf
page 78: this is the result of the sommation performed with a simple resistor sommator at the outputs of a DCX2496 digital crossovers. Different classical crossovers are compared to the Le Cléac'h crossover, only the first order Butterworth (LP and HP in phase) is a bit better than the Le Cléac'h crossover .
page 82 and 83 using the spectrogram to align a 2 ways system using a Le Cleac'h crossover
Notice: page 46 group delay curve (delay T is expressed in equivalent length d calculated by d = T . c with c = celerity of sound) for Marco Henry's Jerzual horn (reference J321). If you use the horn above 750Hz the delay variation is less than 6 centimeters (expressed in equivalent length). If you use a high pass frequency lower than 750hZ then there will be some difference with the simulated response obtained using my excel spreadsheet. Same thing happens if you use a too low frequency for the low pass of a bass driver (when the group delay rises).
Best regards from Paris, France
Jean-Michel Le Cléac'h
on the document downloadable at:
http://freerider.dyndns.org/anlage/LeCleach.htm
On page 52: this is a pulse response I measured on a two ways system using a Le Cléac'h crossover (the bass enclosure is a bass reflex quasi 2nd order using a low tuning frequency, its response is nearly the one of a closed enclosure, low group delay below 70Hz).
Page 68 of the same document: this is the pulse response measured on the system I brought at ETF2004. THe measurement was done the day before the conference I gave on "phase distortion".
You can see others pulse measurements and curves derived from pulse measurements on the document:
http://www.melaudia.net/zdoc/distorsion_de_phase.pdf
page 78: this is the result of the sommation performed with a simple resistor sommator at the outputs of a DCX2496 digital crossovers. Different classical crossovers are compared to the Le Cléac'h crossover, only the first order Butterworth (LP and HP in phase) is a bit better than the Le Cléac'h crossover .
page 82 and 83 using the spectrogram to align a 2 ways system using a Le Cleac'h crossover
Notice: page 46 group delay curve (delay T is expressed in equivalent length d calculated by d = T . c with c = celerity of sound) for Marco Henry's Jerzual horn (reference J321). If you use the horn above 750Hz the delay variation is less than 6 centimeters (expressed in equivalent length). If you use a high pass frequency lower than 750hZ then there will be some difference with the simulated response obtained using my excel spreadsheet. Same thing happens if you use a too low frequency for the low pass of a bass driver (when the group delay rises).
Best regards from Paris, France
Jean-Michel Le Cléac'h
swak said:
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