# REW with dual subs



## Mal01 (Feb 11, 2010)

I have got everything i need to get started and try to learn how to do this. Please forgive my ignorance, but i have dual subs and a pre/pro with dual sub management, do i measure each one individually or together? If together how would i do the connection at the pre/pro?

Thanks.


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## Moonfly (Aug 1, 2008)

Initially you should ensure you balance your subs by setting up the gains on them individually. Measure their output using a test tone and an spl meter. Do this individually and ensure they both measure 75db at the listening position, use the gains on the subs themselves to balance them. If they are stacked they will likely be very similar, if not than there might be a slight difference in the gain settings. You can then turn both subs on together and run REW. This will measure them together as though they were a single sub, (they obviously arent, but they will always play together and so the final sound will always play as one, which is why you always measure the response of multiple subs combined). Do this prior to any eq and save the graph for later.

Then run the auto setup on the processor. This will take care of everything for you, so connecting them one to each input isnt an issue. One its done its thing you can measure them together again and you will be able to see what the auto setup has done to improve things.

If your not bothered about the before and afters, then you needn't do the before graphs if you dont want. I would however still do the basic balancing of both subs manually, it will help get the best from the eq'ing process.


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## Mal01 (Feb 11, 2010)

Thanks for the info. I have the Onkyo pre/pro 5508 with xt32 and have already set the subs up, but will obviously do it again. I still don't get how to run both subs at once, maybe use a splitter into the dual sub outs on the 5508?


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## Moonfly (Aug 1, 2008)

Do you have your subs stacked or spread out, and have you done anything to locate the best positions for them, or are you restricted in where you can put them?


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## Mal01 (Feb 11, 2010)

They are separated. I`ve done the sub crawl to try and find the best placement. I have a little flexibility in where they can go.


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## Moonfly (Aug 1, 2008)

Right, well I would use REW rather than do the sub crawl method personally. Each sub should be individually connected to the processor, one cable from each to one of the inputs on the pre/pro, does not matter which goes where.

When you have a lot of possible locations, I always measure each individual location, and overlay the responses to find 2 locations that look to work together best. I do this to speed up the process of deciding where to put the subs, measuring a single sub in each location is quicker and easier than measuring all the possible combination of the available positions. 

Once you settle on the 2 spots your sub will live in, balance them manually as I described before. This ensures both subs will play equally in the listening position. Its less of an issue for you anyway as your processor will ensure they are properly balanced, but helping them out as much as possible ensures best results from any eq. For people with only a single sub output, this step is very important as the AVR wont individually balance them.

Once your good to go, run Audyssey and the subs will be set up correctly. As I said before, you can run REW to check what the eq has done, and run before and after graphs if you want compare those results.


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## Mal01 (Feb 11, 2010)

I will use REW to help with the best placement, that`s why i want to do it, it will probably take awhile to figure it out though. One more thing, i have burned a cd with test tones from this site, do i keep the cd in my computer or use it in my cdp? I put it in my cdp and it would not play.


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## Moonfly (Aug 1, 2008)

It will likely play on a DVD or BR player, which would be my preferred option TBH. REW itself is capable of generating any tones you want though. You can use REW to get your subs as best as possible before you eq anything, and thats the beauty of it. Even with auto eq these days, there is still something to be said for putting a little effort in yourself.


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## Mal01 (Feb 11, 2010)

Oh, ok, that`s great to know. I thought i was going to have buy one, was looking at the one from Rives.
I have a really nice system and nice new subs and really want to get the best out of them, hopefully REW will help me with getting maximum performance.

Thanks Moonfly.


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