Wireless sub latency

[robbnj]

Is it possible to test latency of a wireless sub adapter using REW?

Long story: Toying with the idea of a wireless adapter for a sub for a simple, inexpensive 2-channel setup in my office (no DSP), and wondering how much better the $200 units are than the $30 units that claim low latency.
Would like to experiment with a few cheap models and see how they perform, since $200 would be silly to spend on this idea.

I tried Googling this with a bunch of different phrases, and came up with a ton of the same hits about setting delays for subs, etc, but hitting a wall on this particular idea.
Seems to be happening a lot with Google lately.

Before I spend a penny: Is it as simple as using a timing referecne to test a main speaker close-miked, then testing the subwoofer close-miked and comparing the tests, or does REW play a timing reference tone for every test? I recall reading somewhere that the timing chirp is too high for subs to reproduce.

 

[John Mulcahy]

You could use the acoustic timing reference played from the main speaker, but you will have to examine the sub impulse response to look at the IR start as sub delay estimates are restricted by the sub's limited bandwidth. Mic needs to stay in the same place relative to the main speaker to let you compare a measurement of the main with a measurement of the sub at the same distance.

 

[Todd Anderson]

You need a way to play a simultaneous pulse at, say, 100Hz, then use the real time analyzer to look and see if the response is happening at the same time. I guess the more synchronized, the louder the pulse would measure?

John, that would work, no?

 

[John Mulcahy]

The scope could be used for that, like this alignment method.

 

[robbnj]

Thank you all, for the responses. I'll look into the impulse and scope info in that link, John.

A thought popped into my head: Would I be able to do it by using a plain loop-back connector for one test, and then connecting the wireless adapter as a loop-back for a second test, then comparing the delay between the two?

 

[John Mulcahy]

No, but you could use a loopback as a timing reference on one channel and connect the adaptor in a loopback on the measurement channel and measure that way.