Acoustic timing reference Signal issue with HELIX DSP

[Gabor Kiss]

Hello Everybody!

I found a problem with the Acoustic timing reference Signal presence in REW. This signal (a short "peep" ) is comig prefectly if I'm using my Home speakers or even Headphones (connected to the laptop) but not playing (or not heard) if I'm trying to play it by my HELIX DSP. (Tweeter is used for reference speaker from 3kHz, full range sweep set in REW)
Only the main test- the full frequency range sweep is heard. Have you ever met this problem? What have I doing wrong?

Thank you for your feedbacks in advance!

 

[sm52]

This can happen if there is a delay (advance) in the reproduction of the test signal. And this may be due to different sampling rates of the measuring and reproducing device. Also because of differently tuned clock generator here and there.

 

[ddude003]

This explanation from @John Mulcahy may help... https://www.avnirvana.com/threads/delay-when-using-acoustic-timing-reference.10901/post-82166

 

[Gabor Kiss]

Thank you for your feedbacks!

2 more things:

- As I see from other posts from John, it's also recommended to switch on: "Adjust clock with acoustic ref" in REW - is it right?
- The other and more important thing is: should we switch off all crossover filters before measuring IR for Time Alignment??? It' recommended also by the MiniDSP website:

https://www.minidsp.com/applications/rew/measuring-time-delay#phase-matching

 

[sm52]

- As I see from other posts from John, it's also recommended to switch on: "Adjust clock with acoustic ref" in REW

Yes. You can enable this option. Or do not turn it on, and after the measurement press 'Estimate IR delay'. But this is only for the first measurement

should we switch off all crossover filters before measuring IR for Time Alignment?

If you do everything from scratch - turn off both filters and delays, measure the IR of all drivers, set delays, and then make filters. But if everything is almost set up and you need to tweak it a little, then you don’t need to disable anything.
.

 

[JStewart]

Could this be a reason?

Power Save Mode
Many newer vehicles feature accessory circuits that remain on for several minutes after the engine shuts off, so an aftermarket amplifier could possibly drain your vehicle's battery. The HELIX DSP solves this problem by turning off the amps connected to its remote output after not sensing music for 60 seconds. The Helix DSP will turn the amps back on within a second after sensing the signal.

Found this info here

HELIX DSP

8-channel digital signal processor

www.crutchfield.com