# Need help setting up mulitple subs



## pietsch288 (Sep 10, 2006)

Here are my questions- I have 4 svs cs ultras all running off of a ep2500. I am running them basically as though they are 2 seperate subs---2 of them are dead center of the back wall and the other 2 are almost dead center of the front wall (one on each side of the canter channel ...so about 2 feet apart). I am running each SET in series to get a aprox 8ohm load (with both sets hooked up the amp see's 4ohm) and then bridging the amp for 2400w @ 4ohm. Ok here's my question-----When I hook up the front subs positive to positive negitive to negitive and do the exact same with the back subs I get an almost perfectly flat line with my sms1 with almost no EQing.
But when I reverse the back 2 subs (front subs are positive to positive neg to neg---- rear are negitive
to positive positive to negitive) ........I get a lot higher DB at certain freq (huge spike @ 25-28) but the freq response is very poor. So which way is correct flattest response or most overall DB but EQ it flat. I feel like I'm "in phase" when I have the most output.... but why am I getting the best responce "out of phase". Which way is correct???? 
please help......thanks


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## thxgoon (Feb 23, 2007)

*Re: how to set up multiple subs properly*

I'm at a loss of words for a good explanation but technically either way is correct. Commercial subwoofers have phase swithces on them for integrating with the mains and it's always whatever setting sounds best is the proper set up. As you've found there are trade off's to each way, in the end it's up to you.

Try moving the subs around the room. Corner locations help with the low frequencies and a cheap eq like the BFD can smooth out problems.


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## Sonnie (Apr 11, 2006)

If you are closer or farther from one set of subs or the other, generally out of phase will sound better and produce a flatter response. If they are equidistant from your listening position, generally they will need to be in phase. At least that is my experience and was my situation in my testing of moving subs around in my HT room.

I had two subs up front, one in each front corner... and one large LLT sub in the back... drivers spaced far apart in a box that was 8' wide, so almost like having them in each rear corner, but about 2' out from the actual corner. I also had issues with cancellations and ended up crossing over the rear a little lower than the front.

It took a lot of experimenting and tons of measuring over and over with various phase settings, but ultimately, since my front and rear subs were equidistant from the listening position, they remained in phase producing a response that did not need equalizing, although I let Audyssey adjust it a little bit.


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## Sonnie (Apr 11, 2006)

Btw... I combined your threads ... :T


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## pietsch288 (Sep 10, 2006)

So loosing a little impact but gaining an almost flat responce is the way to go? For the most part there is no write or wrong?


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## pietsch288 (Sep 10, 2006)

I am using an SMS1 for eqing and xover duties. I'm letting my denon 2808 audyssey set up phase between the subs and the mains. My room is 15.5w x 28 x 9.5. I'm just wondering about subs. I'm looking for the cleanest most accurate bass (LFE). As you can see I have a small room with alot of sub and I'm growing a little tired of too much sub sound (seems a little boomy). But there is no substitution for the feeling the subs make (I tried buttkickers but didn't like them). So now I'm just making sure I'm setting them up by the book.


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## thxgoon (Feb 23, 2007)

If you want them set by the book, their levels should be as flat as possible and matched to the level of the mains. This doesn't always result in room shaking or satisfying bass. Adding a house curve to your eq settings can help you get that low end without sounding 'boomy', though I don't know how to apply it to the SMS.

Also, double check the phase and distance settings set by the Audyssey. Sometimes they can be a bit wacko


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## pietsch288 (Sep 10, 2006)

So this is how I've ended it as of today, and pretty sasified. I'm running the svs's @ native hz (20hz---all ports open), I've got the shelf (house curve) set flat from 20hz-32hz and sloping @ 48db per octive after 32hz. It seems like I'm xover very steep but I have my mains runnning down to 40hz (klipsch rf7's). Besides when I get around 30db per octive I get too much sound out of the subs (which is what I was trying to avoid). I do feel like I could use more 16-20hz, but its probably because I'm so used to the bass overpowering everthing. Allmost forgot I decided to split the front 2 subs (I have one in each front corner) and kept the back 2 dead center of the back wall and they are what I would consider "out of phase", but that is by far the best sounding (and feeling) bass I have yet to find in my system.


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## thxgoon (Feb 23, 2007)

Sounds good :T


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## Sonnie (Apr 11, 2006)

Sounds like you got it worked out.

Post us a screen shot of your response from the SMS-1.


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## pietsch288 (Sep 10, 2006)

One of the behringer eq units lets you set up phase-time delay-eq-xover for each of my subs indivually, I think you can do up to 6 speakers (I forgot the model #). Would this be a must have for my sustem. I ordered another ep2500 last week (thanks to live search) so I can have a power supply for each and every sub (I wouldn't have to pair them up anymore) and with the behringer unit I could set up each indivually. Or am I probably 95% as good as its gunna get? I heard somewhere that the best way to set up 4 subs is to have a sub dead center of each wall and I can't do that because I can't set phase on the side subs. thanks in advance........rich


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## pietsch288 (Sep 10, 2006)

I did also hear that setting them dead center of the front and rears wall was almost as good as the 4 wall thing.

Either way would I gain anything with the time delay If the subs are front and rear wall.


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## pietsch288 (Sep 10, 2006)

I think the behringer unit is a DEQ2496. Would I gain anything by adding one to my system (so I can adjust phase-time delay for each sub. Or is it as good as its gunna get? I feel like I shoud be getting more output from my subs. When there in phase I get aprox 10 to 15db higher but the freq responce looks horrible. Out of phase its flat line city which is cool because fire feels like fire and I can feel the different pitch's of bass but it has way less output..... so is there a happy medium. Is my ony option to add more subs until I get the feel I'm looking for (I really feel like 4 cs ultras should be over kill for my room).


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## pietsch288 (Sep 10, 2006)

hey great news...got er all dialed in. I will post a screen shot of the sms-1 this weekend. Ignore all my last posts. I don't need anything else I do have more than enough bass just wasn't setting it correctly. I ended up putting 1 sub back right corner 1 back left corner and the other 2 dead center of the back wall. I then set the sms-1 to 80hz and eq'd it flat from 16-80 or as close as I could get. Then I ran audyssey and it did a pretty good job of smoothing out what I didn't think could get any better. It even gave it a little bit of house curve. I noticed that audyssey likes less subwoofer volume than I do so I set the xover @32hz and 6db slope and grabbed the remote for some black hawk action. After watching and switching back and forth I decided to leave it @ 12db slope @ 32hz. I would have had to go to 18db if audyssey have not set a mini house curve for me. So thanks for all the help everybody I appreciate it.


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## Sonnie (Apr 11, 2006)

Sorry we did not get to your questions any sooner, but at least you got it figured out.

Audyssey did me right on my sub eq as well.

Show us some graphs! :T


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## pietsch288 (Sep 10, 2006)

I wasn't being sarcastic, I've asked many many questions over a somewhat lengthy period of time. I was close a couple of times but nothing like this, I think I was hevy in the 25-28hz range so all the bass sounded the same and was somewhat overwhelming so I made it a point to set it as close to flat as possible. Since I've tweeked to a small boost @ 17hz with a very very small slope to 31hz and then a house curve from 31-80 like I mentioned earler. thanks again, rich


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## pietsch288 (Sep 10, 2006)

I live here in old north dakota so there isn't any place (quality hometheater store ect- or even actual theater itself) that I can compare my system to. So I'm wandering is there a general guidline as far as how many db would be the max you would want in a certain scene in a movie. Now I am well aware that you wan't as much 12-16hz that you can afford. But say in the 20-32hz there is more actual sound at 32hz then at 20hz and at some point it affects the overall clairity, or at least gets a little over powering. For example in black hawk down there are a couple of helicopter scenes where the bass seemes a bit much but two scenes later there's another copter scene where I want more than what I have, so I don't want to turn it down. I am wandering should I 
A. set the xover slope to a steeper slope (its at 31hz with a 18db slope)
B. or set the xover lower with a less steep slope. (something like 25or 28hz and a 12 db slope

I guess what I'm getting at is how do I know how much is supposed to be there or how steep the slope should be if I have nothing to compare it too.


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## pietsch288 (Sep 10, 2006)

ok, I just read the house curves sticky again (probably read it at least 5 times). But none of it pertains to the SMS-1. Is there a holy grail for setting a up-EQing and applying a step by step house curve (or with my case a "hard knee house curve) with the SMS-1. The article says to make a 30hz sine wave sound like a 80hz---are you supposed to eq it to a flat responce first and then play the sign waves to get your target? Then are you supposed to un-eq it, apply the target curve and re-eq hopefully using less "bands"? Like I said before I'm very close but my subs need a little something and I don't know what because I have nothing to compare them to.


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## thxgoon (Feb 23, 2007)

pietsch288 said:


> how many db would be the max you would want in a certain scene in a movie. Now I am well aware that you wan't as much 12-16hz that you can afford. But say in the 20-32hz there is more actual sound at 32hz then at 20hz.


Generally speaking in a properly calibrated system, max output from the sub should be 115db at the seat. But that's only if the recording engineers mixed the effect at max level.


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## Sonnie (Apr 11, 2006)

When he talks about a 30Hz tone and an 80Hz tone, he means that they "sound" about the same loudness. You definitely do not want them eq'd the same level. If you get both of the "sounding" about the same, they will be 10-12db apart in level... in most cases.

You can ask about the house curve in the BFD Forum to learn more about it... or in the house curve threads.


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## pietsch288 (Sep 10, 2006)

so I should eq flat and play 31hz and a 80hz signwave so they sound the same @ 115db to get the house curve target. Then re-eq from scratch with the house curve applyed. Because I would probably not need to eq a aggressivly in the higher hz range?

If the goal is 115db should my house curve be approx 35db (115 - 80 = 35). If of couse you watch movies @ 80db


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## thxgoon (Feb 23, 2007)

You don't have to do it at 115db, that could damage your subs. Just do it at a normal listening level.


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## pietsch288 (Sep 10, 2006)

but is that correct aprox xover slope?


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## pietsch288 (Sep 10, 2006)

can I use REQ wizard in conjunction with the SMS-1?


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## thxgoon (Feb 23, 2007)

yup! :yes:

It'll help you figure out how to set up your crossover range as well. Take a measurement of just the mains to see where they leave off.


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## pietsch288 (Sep 10, 2006)

I'm getting closer. I set a straighter line between 31 and 80, focusing on making sure it starts sloping @ 32 dropping 10-12db by the time it gets to 80hz. And I eliminated the 3db gain @ 17hz (I was getting bottoming in certain movies), so I decided to leave all the ports open (20hz tune) setting the subsonic to 18hz with a 18db slope. It seems to be much cleaner sound, not quite as much impact but much smoother tighter bass. The problem wasn't extreme action movies (with so much going on its hard to till that the bass seemed a little muddy). But when I threw in Wanted or the new X Files it was too much. So I'm getting closer.......I think :>)


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## pietsch288 (Sep 10, 2006)

hey, are you guys running audyssey first (no eqing) and then tweeking when its done? Or are you eqing and then running audyssey?


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## pietsch288 (Sep 10, 2006)

I am finding that I like to start my house curve around 25hz and slope it a little steeper 15-18db lower @ 80hz. Is this uncommon? I don't wan't to be missing anything but the atmospheric type bass is a bit too much sometimes, on the other hand I don't want give up the feel of the copter-gunshot-explosion ect. So is the problem more when they make the movie it isn't designed for feel (seems like the frequencies I like in the copter scene are the same ones they use in the....I can't believe you just said that scene). In the copter scene its awesome in the later its annoying. So I started going lower and steeper with the xover point but maybe I should leave it at 32hz and 12db slope and turn down the volume about 10db or something. Maybe I still don't have something right? I am getting just over 100db at 16-22hz ish, and that seem ok. Any suggestions? One last thing I am running all 4 cs ultras on 1 ep2500 is that enough power? I actually have two of them should I be using both of them? thanks......rich


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## thxgoon (Feb 23, 2007)

If the clip light on the EP2500 is coming on you may want more power but you don't want to over power them either. Do you know the power rating for them? At this point calibrating your system comes down to personal taste but it sounds like you're getting closer.


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## pietsch288 (Sep 10, 2006)

The 12" PCU comes with a 550w bash plate amp, so I figured 500-700 watts of dj power amp would be plenty. I checked the svs site but couldn't find an actual power rating for them. In bridged mode the ep2500 puts out 2400w so each sub should be getting aprox 600w assuming the behringer rating isn't sugar coated. The nice part of running them all bridged off of 1 amp is that I don't have to worry about 2 or more volume levels. But I certainly don't want to under power them either.


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