7.2 ch versus Y-splitter?

Talon_Sr

I have a simple question. If a 7.2 ch receiver uses two pre-amp outputs for subs, wouldn't that be the same as splitting a single line output from a 7.1 ch receiver? Since the signal is not amplified, would there be any degradation, if you just simply split the sub line out at the receiver before it gets to the subs where their filters take over and then are amplified by the subs themselves? I guess I'm asking, isn't a split subwoofer line out on a 7.1, really the same as a dual line out on a 7.2 because the pre-outs on receiver are not discretely amplified?

Hermitism

http://www.differencebetween.net/technology/household-equipments/difference-between-7-1-and-7-2-surround-sound/

A lot of people using two subs use a splitter, because theirs only has one sub out. They say it really helps fill and even out the room by using two subs. I had mine set up that way, but I wasn't using both at the same time. I used the 8" sub for music and the 12" for HT, but I got tired of having to get up and turn one off and the other on. So now I've just got the 12" connected. I'm not really feeling the love for either of mine.

deronb1

Yup, you will be fine. Just use a quality splitter. Also, try and use the same length run to each sub.

classic carl

My HT receiver is 5.1, but I also use a splitter to add a second sub.

Talon_Sr

Thanks, guys. Great, so now I don't have to upgrade my receiver just to run two subs. Still trying to solve the center channel dilemma. These Mediabridge sub-cables look nice and they have the splitter I would need. Anyone have bad experiences to report on these?

Talon_Sr

deronb1 wrote: »

Yup, you will be fine. Just use a quality splitter. Also, try and use the same length run to each sub.

Well, I have a 15ft for the sub farthest away from the receiver and was thinking about just an 8ft for the second sub closer to the AVR. Will it really make that much of a difference? Are there phase problems to consider with unequal lengths? Or is it the possible electrical hum. The cables are magnetically shielded.

deronb1

Talon_Sr wrote: »

Well, I have a 15ft for the sub farthest away from the receiver and was thinking about just an 8ft for the second sub closer to the AVR. Will it really make that much of a difference? Are there phase problems to consider with unequal lengths? Or is it the possible electrical hum. The cables are magnetically shielded.

Possibly. May be unnoticeable, but it never hurts to be proactive. I have my two subs the same distance from each front speaker. Symmetrical if you will. Are they the same sub?

Talon_Sr

deronb1 wrote: »

Possibly. May be unnoticeable, but it never hurts to be proactive. I have my two subs the same distance from each front speaker. Symmetrical if you will. Are they the same sub?

Yes, well so are my subs (same distance from front speakers), but they are different distances from the receiver. No they are different models and makes. But until I can sell my original sub (just got the 505 two days ago), I figured I might as well use it.

deronb1

Heck, give it a try. You aren't going to hurt anything.

EndersShadow

Talon_Sr wrote: »

I guess I'm asking, isn't a split subwoofer line out on a 7.1, really the same as a dual line out on a 7.2 because the pre-outs on receiver are not discretely amplified?

From a connection standpoint correct. The ONLY thing I will add is that if the calibration software in the AVR can independently EQ each sub, then sum the result then its not the same. If it just treats it like an internal splitter (which I believe most do) then your doing the same thing, just outside the AVR.

IIRC currently none of the AVR's independently EQ each sub then sum the result. Unless Audyssey SubEQ does that but I dont believe it does...

Talon_Sr

EndersShadow wrote: »

From a connection standpoint correct. The ONLY thing I will add is that if the calibration software in the AVR can independently EQ each sub, then sum the result then its not the same. If it just treats it like an internal splitter (which I believe most do) then your doing the same thing, just outside the AVR.

IIRC currently none of the AVR's independently EQ each sub then sum the result. Unless Audyssey SubEQ does that but I dont believe it does...

Good point, I hadn't considered that. My Pioneer uses the MCACC calibration (not the MCACC Advanced which has a separate sub calibration routine). Will the MCACC I have calibrate with both subs connected, as two separate subs or just one? I mean during the routine, the program will check for distances. And, of course, it sets channel levels, standing waves, reverb, and EQ from that distance reading. How would it reconcile two different sub locations for that? Maybe it would be better to turn my secondary sub off during cal, and then hook it back up afterwards. Or, perhaps, I could use the one sub for LFE (line level sub-out from AVR) and the other for filtered bass by fronts pre-amp out > subs L/R in > sub L/R speaker outs > fronts speakers in. Is that a possibility? And if so, would I then set the fronts as Large? Also wouldn't I have to keep my sub setting for the AVR as "Present" for the Line-out sub?

EndersShadow

MCACC makes that a moot point. Carry on as planned and it will work the same with a Y splitter as it does without.

And I should add normally you dont run into issues unless your subs are NOT the same distance to your main listening position, which is uncommon.

mufsoman

Talon - I used a splitter for quite some time before I got the SMS-1, just use a quality splitter. I used an Audioquest. I ended up with three of them due to other bi-amp trials I was doing. Send me a PM if your interested in one. If the subs are the same, phase may not be a problem, especially if they're both in the front or back. If one is sealed and one ported or you if have a large room with one in front corner and other in opposite back corner, then phase could be more of an issue. It really comes down to room response. If you have a CD with frequency range test tones, play the 80hz tone. Sit in your rig's sweet spot and have some one adjust the phase on one sub. You may hear a difference at a particular setting, if so, set for your preference. Use a dbl meter, if you have one, if you don't trust your ears. I did this for each of my three subs, each pair and all three together. Multiple subs definately help to balance the bass response.

Talon_Sr

Mufsoman, I ordered a Mediabridge splitter early this morning along with a 15ft sub cable. Amazon sells them. I already have one for the PSW505 and they look really nice. Something like $10 apiece.