Measure with Time Reference - Timing Offset

[Alpi]

Hi,

I would like to measure with a time reference, but what do I have to enter for timing offset? What does that mean exactly?
How do you proceed exactly? And if the left LS is the time reference, is that correct when you measure the left LS or do you have to use the right LS as the time reference?



Thanks

 

[Alpi]

Hi,

I have done the following, maybe someone can tell me if it is correct.

I defined the left LS as reference and then measured the left LS.
Then I entered the delay that you can see in the left red circle in the Timing Offset.



Is that correct?

 

[John Mulcahy]

Yes, that should be fine. You can check by measuring again without moving anything. Use the same timing reference output for all measurements whose relative timing you want to compare.

The timing offset is less important when using the acoustic reference if the reference is one of your speakers. It is mainly used with a loopback connection, since in those cases the additional time it takes sound to travel from speaker to microphone needs to be removed. With the acoustic reference that is already taken into account, hence the very small delay figure you saw.

 

[sm52]

John, can an acoustic synchronization signal be applied to the speaker to be measured?

 

[John Mulcahy]

Yes

 

[sm52]

I tried. Is it normal that with this variant Timing Offset -0.004 mc after pressing 'Estimate IR delay'? Distance from tweeter to microphone 2.68 m.

 

[John Mulcahy]

Yes.

 

[sm52]

I thought about the question from post #4. If the first speaker to be measured is a tweeter, then everything is fine. But if the second is midrange or midbas, then during the measurement (after the reference signal) 2 speakers will work. This is not what we want. It turns out that the reference signal should be fed to another output of the sound card.

 

[John Mulcahy]

I'd refer to those as "drivers" rather than "speakers".

 

[sm52]

Yes. If we measure the tweeter first, then the midbass, and both are in the same enclosure. So my reasoning is correct?

 

[jtalden]

Yes, that is correct. For driver timing in a box use a different channel speaker for the reference.

 

[Alpi]

Hi John,

sorry for my late Answer.

For my complete understanding:

When my reference ist the left speaker and i measure the left speaker why have i a Delay of 0,152ms? That is the same Speaker?
Why have i this Delay?

If that is normal must i put the value 0,152ms to the field "timing Offset"?

I want look with "Overlays - Impulse" if the LS (li, re, ce, and rears) playing at the same time. look Picture



Thanks

 

[John Mulcahy]

It is the difference between the timing of the tweeter-only timing reference signal (a high frequency sweep) and the overall timing of the combined response of whichever of the speaker's drivers were active during the measurement sweep (which depends on the frequency range chosen for the measurement sweep). Whether there is a delay when measuring the timing reference speaker depends on the speaker design, 0.152 ms is quite a small delay but you could apply it as a timing offset if you wished. That won't affect the timing of your speaker measurements relative to each other, just where they appear relative to zero on the time axis.

 

[Alpi]

Thank you!!!
Super explained and now I understand - Thanks!!!