[jaylevine]

This may not be the right circle, but does anyone have a standard approach to dialing in two subs? I recently added a second Rel Strata III to my room--didn't get the results I was hoping for.

I used the tried and true method to dial in the original sub, I.e., moved it around from corner to side wall and listened to what was best from my listening position.

Do you approach two subs the same way? I've hooked up the Rels one to each channel, so using the method to dial in a single sub that is combined left and right doesn't seem intuitive to me if each sub is now on a separate channel.

[rockadanny]

Granted, I did not research much on this but there are supposed to be excellent references (Floyd Toole, Duke LeJune, Earl Geddes). I may just have been lucky but this is what I did ...
I placed one sub very close to one of my main speakers and dialed that one in - easy. I then placed the second sub on the other side of the room, about half way up the side wall, near the side wall. Then slid it around that general area, mostly up/down the wall length but also closeness to the wall, until I found an optimal spot for it. I did this with a test CD playing both channels at all times (40 Hz so my mains as well as subs were all producing sound, but subs more so than mains). I too have one channel sent to each sub. It is my understanding that much recorded music sum the low frequencies to both channels anyway, but not all.

All of this was done intuitively after a little research, worked well for me, but might not for anyone else's room as I am NO expert. Just a HAPPY listener. Hopefully the experts will chime in to help you as well. Good luck!

[jaylevine]

". I too have one channel sent to each sub. It is my understanding that much recorded music sum the low frequencies to both channels anyway, but not all. "

Thanks. If that is true, then I'm wondering if I should just hook the Rels up in "parallel", ie summing the two channels (which is how Rel recommends just one sub hook up), and then place the second sub behind me like a lot of folks do with their home theater set up.

[rockadanny]

Stereo or summed mono subs is not the issue. It is the interaction with the two subs and your room. You can just throw the second behind you if you wish, and you might get lucky with its location, but summing the two will not reduce the work necessary to dial them in correctly. Sorry.

[SoCalWJS]

How much freedom do you have in placement of either or both subs?

One suggestion. YMMV.

If possible, keep the first sub in the location you were using it (I'm assuming it was about as good as you could make it sound at that location). Place the new sub in your primary listening position. Send a signal to the new sub and walk around the room and check for the flattest/best response. Now send signal to both subs, and recheck - see if still sounds/measures good. Swap second sub from listening position to that location. Now check sound from listening position.

Also, experiment with the phase of each sub.

[max190]

How do you have the subs hooked up to your system...
High level spkr or low level from pre?

[jaylevine]

How do you have the subs hooked up to your system...
High level spkr or low level from pre?

Per Rel manual, high level speaker.

[Ethan Winer]

Stereo or summed mono subs is not the issue. It is the interaction with the two subs and your room ... summing the two will not reduce the work necessary to dial them in correctly.

Exactly. The fastest and most direct way to find where best to place subs, and how to balance their volumes and phase adjustments (if available), is to measure the low frequency response at high resolution as you experiment. Anything else is just guessing. You might get lucky! But measuring gets you there faster, and ultimately with more accuracy. This article shows a clever way to speed up the process further using the RTA feature of the Room EQ Wizard software:

Room Measuring Primer

But it will still take a while.

--Ethan

[John Casler]

This may not be the right circle, but does anyone have a standard approach to dialing in two subs? I recently added a second Rel Strata III to my room--didn't get the results I was hoping for.

I used the tried and true method to dial in the original sub, I.e., moved it around from corner to side wall and listened to what was best from my listening position.

Do you approach two subs the same way? I've hooked up the Rels one to each channel, so using the method to dial in a single sub that is combined left and right doesn't seem intuitive to me if each sub is now on a separate channel.

Hi Jay,

If you can you might experiment with a "push/pull" type set up.  That is:

Place the first sub in the front as you find it works best.

Quite often it is best to place it "precisely" the same distance from your ears (measured) as the main speakers.  This will help reduce phase and integration issues with the front sub and the main speakers.

Place the second sub immediately behind the listening chair or couch "FACING" away from the front sub and in phase with the front sub.

This positioning will create an energy synergy relative to the air movement in/at the listening position.  It will also create two VERY DISSIMILAR radiation paths to all wave launches, and room interactions.

It is helpful if you have the ability to adjust phasing or timing on the rear sub so you can experiment with that, or you can move the rear sub closer or further away from the "rear" wall if you do not.

Quite often many consider unequal room boundary placement a good place to start, but with two subs you can often get exceptional results with the above off boundary efforts.

There are also many other "out of the box" methods (like placing one sub well away from the actual listening position, (like down a hallway 30-40 feet away) that also produce some unexpected results.

Don't be afraid to "fool around" and think out of the box. . . you don't have aloft or open second floor do you?

[rodge827]

I'm using a DSPeaker Anti-Mode 8033s on my two subs.

http://www.dspeaker.com/en/products/anti-mode-8033.shtml

Line level only but did a world of good taming room nodes and nulls. I was also able to get rid of some bulky bass traps and made more space in the room.

Good-Luck,

Rodge

[JohnR]

Try putting one in the center of the front wall and one in the center of the rear wall. Or put both very close (0.5m) to the listening position. Other than that... I'd second the suggestion of spending a little on measuring gear.

[jaylevine]

Progress so far:

Sub one in corner behind speakers with sub two behind listening area yields the best freq response (using REW 0--200hz sweep). I tried about ten different arrangements (locations, cut over freq, etc). Single sub in corner measures better in some limited  ranges but two subs as configured above is the overall flattest. There is a huge dip (35db) at around 100hz and 170hz. Haven't messed with phase yet.....still messing around to better understand waterfall graphs and other graphs. Lot of fun moving this stuff around Also will be looking at investing in electronics as some have suggested, but they seem pretty pricy and will probably invest in room treatment first.

The room is huge, ilregularly shaped and full of reflective surfaces. Unfortunately we want to move so no room for investing in acoustic treatment. Next home will have a dedicated listening room.....

[ctviggen]

I'm using a DSPeaker Anti-Mode 8033s on my two subs.

http://www.dspeaker.com/en/products/anti-mode-8033.shtml

Line level only but did a world of good taming room nodes and nulls. I was also able to get rid of some bulky bass traps and made more space in the room.

Good-Luck,

Rodge

Does this actually work with two subs?  I have two subs I cannot move, and this seems like an ideal solution, but it's not clear to me even after downloading the manual this device supports two subs.

[jaylevine]

Does this actually work with two subs?  I have two subs I cannot move, and this seems like an ideal solution, but it's not clear to me even after downloading the manual this device supports two subs.

It looks like the "S" model handles two subs.

[ctviggen]

It looks like the "S" model handles two subs.

It does appear so, though they really need to make this clearer.  It's about $500 for this.  I wonder what the import fees/duty and shipping would be. 

[ctviggen]

Figured it out.  Not sure about the duty, but shipping included the device is about $550. 

[jaylevine]

Figured it out.  Not sure about the duty, but shipping included the device is about $550.

Actually that isn't too bad. I visited a shop recently to look at acoustic treatments. Would cost me about $2k do a room like mine.

Do folks generally feel electronic solutions work as well as room treatments?

[JohnR]

Depends which one you're selling.

But seriously, they're different tools. Do the decay plots here to see what you have now.

[ctviggen]

Actually that isn't too bad. I visited a shop recently to look at acoustic treatments. Would cost me about $2k do a room like mine.

Do folks generally feel electronic solutions work as well as room treatments?

I have some acoustic treatments (7 Realtraps and 2 soffit traps and 2 sub traps/stands), but I still want some DSP capability.  Room treatments are better in the sense they lessen modal ringing (eg, how long a sound at a certain frequency takes to decay). 

I could also use a miniDSP, but then I'd have to do work. But it's way less expensive.  Unfortunately, time for me is the big issue.  I still haven't programmed my HT remote the way it should be programmed.  I need something that's fast.

[jaylevine]

Depends which one you're selling.

But seriously, they're different tools. Do the decay plots here to see what you have now.

Great article, thanks.