Adding a 2nd subwoofer

rdb2001

Another Polkie and myself were having a discussion about adding a 2nd subwoofer. I have my 2nd one on the way and will be here thurs. The question that came up, because we have to use a y-splitter to hook up a 2nd sub, will it take away from both subs. I know the subwoofer hook up is a pre-out, so I am guessing it would have some voltage like car headunits preouts. So would hooking up 2 with a y splitter take away from the performance of both because of that? Looking foward to your replies.

LandShark

I have 2 subs, a Velodyne VRP1200 and Velodyne VRP1000. The way I have them run and It's incredible is...a Y-splitter from the pre out on my Onkyo 705 with monster sub cables going to each Velo. At the sub connections I have Y splitters again going to each sub input. Might not be necessary but works perfectly for me! ( had a guy 2 blocks away from my home knock on the door the other night and say I was shaking the neighborhood...lol)

thsmith

No worries using a splitter to feed 2 subs. Just make sure you use good cables to subs.

I had 3 subs running off one splitter.

gtu2004

anyone has a good recommendations as to what splitter cables to use (probably from monoprice or ebay or wherever...)? I'm thinking of adding another sub. and should the subs be identical (i.e. driver size etc)l?

pearsall001

gtu2004 wrote: »

anyone has a good recommendations as to what splitter cables to use (probably from monoprice or ebay or wherever...)? I'm thinking of adding another sub. and should the subs be identical (i.e. driver size etc)l?

In a perfect audio world, yes the subs should be identical. But sometimes that's just not the case. A lot of guys run different subs with great results.

A good Y spliter is available from a lot of cable manuf. I wouldn't concern myself with that too much. Best Buy & CC carry them also.

rdb2001

Ok, see I have a friend with a SVS nsd10 sub. He hooked up an onkyo 8 with it. He said that the svs sounded louder and better hooked up by itself. I am about to receive my 2nd Boston Acoustics 12 thursday and is hoping that I am not taking away the performance of one because I am hooking up to. I hope it will work out. Should I run audyssey with both subs hooked up at the same time?

Eric W

gtu2004 wrote: »

anyone has a good recommendations as to what splitter cables to use (probably from monoprice or ebay or wherever...)? I'm thinking of adding another sub. and should the subs be identical (i.e. driver size etc)l?

Yes, strongly recommended to use identical subs (same model- same woofer size is not enough). The reason is different phase characteristics between different model subs. In other words, if you don't use two identical subs, at some points the subwoofers will cancel each other, at other points they will reinforce each other causing a jagged frequency response.

rdb2001

Eric Wong wrote: »

Yes, strongly recommended to use identical subs (same model- same woofer size is not enough). The reason is different phase characteristics between different model subs. In other words, if you don't use two identical subs, at some points the subwoofers will cancel each other, at other points they will reinforce each other causing a jagged frequency response.

Ok with that being said when u r adding the same type 2nd sub, are you hurting them because you have to use the same pre-out. I havent really gotten a solid answer yet.

McLoki

rdb2001 wrote: »

Ok with that being said when u r adding the same type 2nd sub, are you hurting them because you have to use the same pre-out. I havent really gotten a solid answer yet.

No, no problem at all. Think of it this way - if you plug two fans into an outlet, does the total airflow go up or down? (does the additional fan overcome drop in voltage from the additional demand?)

You could plug in 20 subs and still be fine.

Michael

rdb2001

McLoki wrote: »

No, no problem at all. Think of it this way - if you plug two fans into an outlet, does the total airflow go up or down. (does the additional fan overcome drop in voltage from the additional demand?)

You could plug in 20 subs and still be fine.

Michael

Thanks. That really helps. I just didnt know because I know preouts normally have some voltage so I was thinking splitting it my hurt the subs performance. Just needed some confirmation. Thanks again.

Eric W

McLoki wrote: »

No, no problem at all. Think of it this way - if you plug two fans into an outlet, does the total airflow go up or down. (does the additional fan overcome drop in voltage from the additional demand?)

You could plug in 20 subs and still be fine.

Michael

What he said- well almost. 2 subs will be fine. 20, probably not. Usually you're safe if you're running 4 or less off one output. After that the paralleled input impedance of each sub may drop too much for the "sub out" to handle. If you want to hook up more then that you'll likely need a distribution amplifier to buffer the output jack.

dkg999

I run two subs with really good results. I have an SVS 20-39PC+ in the front left corner, and an SVS PB10-ISD in the right rear corner. I live in an apt, and by using the dual subs I can pressurize the room with low freq and low volume levels, and still have bass I can feel, and happy neighbors. The Y-splitters from Outlaw were the best I could find when I bought mine, and I use a single y-splitter from the sub output on my AVR to send signal to both subs with no problem.

When I calibrate my system, I turn off the rear sub. Once I have it dialed in with the front sub, I then turn on the rear sub and adjust the level and phase controls to get the desired effect. If you carefully adjust the phase setting on the rear sub, you can cancel out some of the bass while leaving the felt impact. Works great for an apt setup!

TNRabbit

Eric Wong wrote: »

Yes, strongly recommended to use identical subs (same model- same woofer size is not enough). The reason is different phase characteristics between different model subs. In other words, if you don't use two identical subs, at some points the subwoofers will cancel each other, at other points they will reinforce each other causing a jagged frequency response.

Subs don't have to be identical. Digital subs or those with room correction software (SMS-1, for example) can be any type. Different subs won't "cancel each other out" as stated. ANY sub will do this if they are not in phase for their placement.

Also, it's best to avoid the y connector & daisy chain them through the RCA input/outputs to each other if they are capable, unless you have multiple sub outputs on your AVR (many new ones do).

Eric W

TNRabbit wrote: »

Subs don't have to be identical. Digital subs or those with room correction software (SMS-1, for example) can be any type. Different subs won't "cancel each other out" as stated. ANY sub will do this if they are not in phase for their placement.

Also, it's best to avoid the y connector & daisy chain them through the RCA input/outputs to each other if they are capable, unless you have multiple sub outputs on your AVR (many new ones do).

They don't "have" to be identical, but they really *should.* Heck nothing in audio "has" to be a certain way, but in many cases there is a better way of doing things.

I have a SMS-1 myself and while it does have phase shift capability, it's still not powerful enough to have frequency dependant phase shift capability which is what's needed to properly compensate and adjust for 2 different models of subs.

And yes, different model subs DO cancel each other out if operating over the same frequency range (I said "at some points"). For example, if you have two ported subs tuned to different frequencies, at the vent tuning frequency the output is 180 degrees out of phase with the rest of the woofer. It's even worse if you have 2 different designs of subs, such as one vented and one sealed.

So if you have two different model subs, with two different tuning frequencies, you have 2 different phase responses, which = cancellation.

As for daisy chaining and Y connector- most subwoofers' (ours and our competitors) ins and outs are simply connected in parallel and are not buffered, so it's the same as using a Y connector.

gtu2004

so would a normal RCA Y splitter cable (which has white and red lines splitted from a single line) be enough? by that i'm asking if this cable is enough:
http://www.monoprice.com/products/product.asp?c_id=102&cp_id=10218&cs_id=1021804&p_id=665&seq=1&format=2

of course that's the cheapest possible cable as an extreme example. and does it matter which line (white line and red line) goes into which sub.

thanks guys.

thsmith

gtu2004 wrote: »

so would a normal RCA Y splitter cable (which has white and red lines splitted from a single line) be enough? by that i'm asking if this cable is enough:
http://www.monoprice.com/products/product.asp?c_id=102&cp_id=10218&cs_id=1021804&p_id=665&seq=1&format=2

of course that's the cheapest possible cable as an extreme example. and does it matter which line (white line and red line) goes into which sub.

thanks guys.

No, that is a stereo cable, you want Mono like this http://www.radioshack.com/product/index.jsp?productId=2103340

gtu2004

thsmith wrote: »

No, that is a stereo cable, you want Mono like this http://www.radioshack.com/product/index.jsp?productId=2103340

ok. that makes a lot more sense. thanks.

engtaz

Works real good. SPL to set level of subs then run setup for receiver for Y cable.

engtaz

Chameleon2

What are the advantages of adding a second subwoofer?

I like the idea of a 2nd s/w, but would like to know what advantages there are from a technical stand point.

Does the 2nd s/w need to placed symmetrical to the 1st?

My current speaker setup is shown below; I sit on the right side of the room (24ft x 12ft); the only place for a 2nd s/w would be behind me (~7ft) on the left side of the room (ahead of the surrounds by about 5ft).

thanks

McLoki

Google "Why multiple subwoofer" (without the quotes)

Chameleon2

ah, forgot about cnet for my speaker information needs!

no second s/w for me.

McLoki

your choice, but multiple subs work great for me.

ESavinon

I use these: http://www.parts-express.com/pe/pshowdetl.cfm?Partnumber=091-515&FTR=091-515&CFID=2804763&CFTOKEN=20945669

Eric W

Chameleon2 wrote: »

What are the advantages of adding a second subwoofer?

I like the idea of a 2nd s/w, but would like to know what advantages there are from a technical stand point.

Does the 2nd s/w need to placed symmetrical to the 1st?

My current speaker setup is shown below; I sit on the right side of the room (24ft x 12ft); the only place for a 2nd s/w would be behind me (~7ft) on the left side of the room (ahead of the surrounds by about 5ft).

thanks

Quite a few- greater overall SPL capability, more configuration options (stack the two for greatest SPL, stagger them in the room for smoothest response over the largest area). With 2 subs playing instead of one, you would run each at a lower volume which = less distortion particularly at higher volumes. The second sub does not need to be placed symmetrically. Infact, placing it asymetrically usually yields smoother response.