Inconsistent timing results

[Tore]

Hi all

Why do I keep getting different results when I take measurements of the same speaker using acoustic timing reference? No change is made between those four measurements, yet REW gives different results.

 

[John Mulcahy]

You'd need to attach or provide a link to an mdat file for anyone to comment.

 

[Tore]

You'd need to attach or provide a link to an mdat file for anyone to comment.

Thank you for the suggestion. Here are some measurements I just made.

 

[John Mulcahy]

Looks like something went awry with the first measurement. A dropout, perhaps. Did the sweep sound normal for that one?

Surrounds aren't always a good choice as the timing reference, they are often close to walls with strong reflections and some have multiple tweeters.

 

[Tore]

Looks like something went awry with the first measurement. A dropout, perhaps. Did the sweep sound normal for that one?

Surrounds aren't always a good choice as the timing reference, they are often close to walls with strong reflections and some have multiple tweeters.

All the sweeps sounded the same. My surround speakers don't have multiple tweeters. All of my speakers are very close to the walls.

I'm having this issue quite often.

 

[sm52]

The difference between the 1st and 2nd measurements in the frequency response is about 750 hertz. Maybe some wire is poorly clamped?

 

[John Mulcahy]

Long HDMI or USB cables can also cause issues sometimes.

 

[sm52]

Long HDMI or USB cables

More than 3 m?

 

[Tore]

Long HDMI or USB cables can also cause issues sometimes.

I actually use a high quality 8 meter USB extender. I'll try without the extension.