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Old 21st November 2020, 11:31 PM   #2451
DaveFred is offline DaveFred  Canada
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Location: London, Ontario, Canada
These two statements seem to contradict each other.

Originally Posted by kimmosto View Post
Accuracy requirement depends on the highest XO frequency. Max 5 mm error is usually okay.
Originally Posted by kimmosto View Post
It matters especially with dual channel because differences in travel distance is saved to phase responses.
Distance from mic to DUT can vary by up to 5mm.

But, distance from mic to DUT is especially important with dual channel measurement.

Why doesn't up to 5mm matter?
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Old 22nd November 2020, 05:50 AM   #2452
kimmosto is offline kimmosto  Finland
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Location: Kuopio
Single channel mode is (almost) blind to sound flying time so it's not capable to measure distance differences. We can also say that distance errors do not matter (much).

Dual channel mode is able to measure sound flying time and distance differences so user should take care that error in mechanical distance from DUTs to mic stays as constant as possible (or known for compensating time offsets). I cannot require absolute zero tolerance from anybody because it's not possible in practice. Remaining error in magnitude and phase responses depend on crossover frequency and c-c distance. Error in power response is small assuming c-c ~ wave length so user should focus to distance error especially while measuring responses within listening window.

Example with acoustical LR24 crossover at 4 kHz. Timing error in upper driver is -5 mm. Magnitude error in axial is no more than 0.2 dB which may not have any effect to simulation producing component values. Error increases with higher XO points, and decreases with lower XO points.
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Old Yesterday, 12:02 PM   #2453
Hensolo is offline Hensolo
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Join Date: Jan 2020
I have two speakers Scan Speak 25W8565-0 and 25W8565-1. They must work in the same enclosure. With bass reflex. The crossover is parallel, the cutoff frequencies are approximately 90 Hz and 170 Hz. I want to learn how to work with the Enclosure Tool. Can someone create a project for these two speakers and give me the vxe file? I tried but failed to enter two different speakers.
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