Cant measure impulse on sub

[Ricardojoa]

i was trying to measure the impulse response with timing reference on sub alone and the measurements wont finish. What am I doing wrong?
Full range is fine, only when i disconnect the main, the sweep wont finish.

 

[John Mulcahy]

The acoustic timing reference is a high frequency signal, it cannot be reproduced by a sub. A speaker with a tweeter must be used to play the timing reference signal.

 

[Ricardojoa]

Thanks John.
If I understand right, with hdmi and usb mic , it needs to use timing reference to measure, how do I measure impulse for the sub?

 

[EarlK]

how do I measure impulse for the sub?

Start be reading through the many self-help articles found within this forum.

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[Ricardojoa]

Ok, I did some reading on this and in order to use timing reference for subwoofer, mic needs to very close to the sub. But what im trying to do is to use the alignment tool to see the delays on main or sub for my MLP. Or am I mistaken, the alignment tool can actually be used without timing reference?

 

[JStewart]

Ok, I did some reading on this and in order to use timing reference for subwoofer, mic needs to very close to the sub. But what im trying to do is to use the alignment tool to see the delays on main or sub for my MLP. Or am I mistaken, the alignment tool can actually be used without timing reference?

The alignment tool can only be used with measurements taken with a timing reference.
For aligning sub to mains the mic must be at the listening position.
Acoustic timing reference speaker used must have a tweeter.

I’m assuming the issue is you can only send a measurement sweep to right or left. Example using right main as timing ref speaker.

Set XO
Turn off sub
Measure fronts (separately if preferred)

Disconnect front left speaker.
Turn on sub
Send sweep to front left

Now you’ll have the measurements you need. You can use REW trace arithmetic to add the front left and right together or add the sub to itself to get relative volumes correct.

If you have a question when getting into it, post the REW .mdat with your question so someone can have a look at your data if trying to help.

 

[Ricardojoa]

Thanks a bunch. It is like magic with your intruction.

 

[mladia]

The alignment tool can only be used with measurements taken with a timing reference.
For aligning sub to mains the mic must be at the listening position.
Acoustic timing reference speaker used must have a tweeter.

I’m assuming the issue is you can only send a measurement sweep to right or left. Example using right main as timing ref speaker.

Set XO
Turn off sub
Measure fronts (separately if preferred)

Disconnect front left speaker.
Turn on sub
Send sweep to front left

Now you’ll have the measurements you need. You can use REW trace arithmetic to add the front left and right together or add the sub to itself to get relative volumes correct.

If you have a question when getting into it, post the REW .mdat with your question so someone can have a look at your data if trying to help.

When you say set crossover.. you mean set it at the highest possible number in the AVR?
Would this help me determine the crossover after? Thank you for your time.

 

[JStewart]

When you say set crossover.. you mean set it at the highest possible number in the AVR?
Would this help me determine the crossover after? Thank you for your time.

Reading your post #5 I was understanding you want to align the sub to the mains. If this correct then you want to set the XO to the value you want to actually use. If you wish to check alignment for other XO frequencies then another set of measurements is required for each.

 

[mladia]

Reading your post #5 I was understanding you want to align the sub to the mains. If this correct then you want to set the XO to the value you want to actually use. If you wish to check alignment for other XO frequencies then another set of measurements is required for each.

I did not write post #5 I do need to know how to choose crossovers using REW. Help?