Impulse Response with timing reference different

Alpi

Member

Thread Starter

Joined

Feb 21, 2018

Posts

72

• Dec 21, 2024

• #1

Hi

I measure my rear array of my DBA with “time reference” (Example) but I always get different impulse responses.
The measurements were made one after the other without changing anything.
Why is that?

the problem is when i work with the alignment tool it gives different results.
Which measurement is correct

thanks

 

Last edited: Dec 21, 2024

John Mulcahy

REW Author

Joined

Apr 3, 2017

Posts

8,169

• Dec 21, 2024

• #2

What is the timing reference?

 

Alpi

Member

Thread Starter

Joined

Feb 21, 2018

Posts

72

• Dec 21, 2024

• #3

"time reference"

 

John Mulcahy

REW Author

Joined

Apr 3, 2017

Posts

8,169

• Dec 21, 2024

• #4

Using the left speaker as the reference? Can you attach an mdat file with some of the measurements, including one of whichever speaker is acting as the reference.

 

Alpi

Member

Thread Starter

Joined

Feb 21, 2018

Posts

72

• Dec 22, 2024

• #5

Only the left speaker
i send the mdat later with the array back measures

 

Attachments

• 
  impuls left speaker.PNG

  1.1 MB · Views: 10
• 
  SPL left speaker.PNG

  1.1 MB · Views: 11

Alpi

Member

Thread Starter

Joined

Feb 21, 2018

Posts

72

• Dec 22, 2024

• #6

mdat from the left speaker and Array Front and back from my DBA

Time Reference is the left speaker.

 

Attachments

• Impulsmessung Av Forum_1.mdat

  6.9 MB · Views: 375

John Mulcahy

REW Author

Joined

Apr 3, 2017

Posts

8,169

• Dec 22, 2024

• #7

Pretty strange behaviours from the left speaker measurements, with odd distortion artefacts that may be a result of missing data. Try enabling the Analysis preference "Adjust clock with acoustic ref", that will make it easier to spot missing data since the clock adjustment would be strongly affected by that. Make sure the CX-A5100 isn't applying any surround mode processing.

 

Alpi

Member

Thread Starter

Joined

Feb 21, 2018

Posts

72

• Dec 22, 2024

• #8

Ok
I measure in straight - thats without any surround mode?
When i enable the Analysis preference "Adjust clock with acoustic ref" i get an error



new messages with the Analysis preference

maybe i have problem with my measuring chain?

thanks

 

Attachments

• Impuls_adjust left.mdat

  2.5 MB · Views: 621

Alpi

Member

Thread Starter

Joined

Feb 21, 2018

Posts

72

• Dec 22, 2024

• #9

I have tried several things to solve the problem but I think that my Tascam US144 MKII may be causing problems. It's a bit older and maybe the drivers are a problem?
I will order the Focusrite Scarlett Solo 3rd Gen and try to measure it.
What do you think?

 

John Mulcahy

REW Author

Joined

Apr 3, 2017

Posts

8,169

• Dec 22, 2024

• #10

It's possible the Tascam is the problem, though it might also be a PC configuration issue or some other process taking priority.

 

Alpi

Member

Thread Starter

Joined

Feb 21, 2018

Posts

72

• Dec 22, 2024

• #11

Thanks John
I have reactivated my old Mess laptop and now everything is working perfectly again. No error message, and the impulse response is always the same.
The Tascam works perfectly.