Y-connector for summing signal. . .bass only???

pjchappy · « **on:** 24 May 2004, 06:40 pm »

What would be the problems w/ using a Y-connector to sum a 2-channel signal. . . for subwoofer use only.

p

Marbles · « **Reply #1 on:** 24 May 2004, 06:56 pm »

Quote from: pjchappy

What would be the problems w/ using a Y-connector to sum a 2-channel signal. . . for subwoofer use only.

p

Describe exactly how you would do it.

pjchappy · « **Reply #2 on:** 24 May 2004, 07:01 pm »

Either from my 2-channel output from my CD-player, or from the pre-out of a future integrated. ..the Y-connector would then be connected to another interconnect. This interconnect would then go into 1-channel of my QSC amp. . .the amp would then be put into parallel mode (same signal in both channels), then bridged. . .then speaker cables would go to my sub.

Is this exact enough?

Thanks!

p

electricbear · « **Reply #3 on:** 24 May 2004, 07:40 pm »

I have tried this at the store and with some products I have found that it makes everything mono.I tried to y out of thepreout on an integrated to run a sub and it caused the speaker outs to go to mono.

rosconey · « **Reply #4 on:** 24 May 2004, 07:57 pm »

do it the easy way and just buy another sub-

pjchappy · « **Reply #5 on:** 24 May 2004, 08:09 pm »

I would LOVE to. . . . but, I am po. ..

p

Rob Babcock · « **Reply #6 on:** 24 May 2004, 08:16 pm »

Does the QSC have a low pass built in? The main problem I could foresee with such a setup is that the sub amp would get a full range signal- you wouldn't want that playing thru the sub!

You'd need multiple Y's to do with with a CD player: first a Y at the CD output to convert the L & R into two jacks each. Then a Y & in reverse to sum on pair to mono for the sub.

If you're amp has an X-over, such a thing could probably be made to work, but I doubt it would be ideal. Seems to me going thru all those adapters may either degrade the sound or allow some hum/RFI into your system. And it would depend how flexible the X-over was in your amp.

A better bet would be to pick up a cheap outboard X-over instead.

rosconey · « **Reply #7 on:** 24 May 2004, 08:26 pm »

you could try the behringer 2channel crossover at parts express for 89$.
has a single sub out , i think its xlr though.

http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=248-664

pjchappy · « **Reply #8 on:** 24 May 2004, 08:37 pm »

Rob,

1st off, my sub has a 90hz low-pass. . .so, that is no problem.

Secondly, I wouldn't need as many connections. . .the QSC amp has a parallel mode, which puts one channel of input and makes the same signal in the other channel (it does not SUM, though). . .then, I use it in bridged mono mode into my sub (the subs low-pass will deal w/ that full-range signal). . .

Soo, here is what it would be like:

CD-L........CD-R
..I..............I
..I..............I
.....I........I
.......I.....I
..........Y
.......Amp (parallel mode; bridge-mono mode)
........I...I
........I...I
........I...I
........SUB (w/ low-pass)

(spaces don't stay spaced)
Would this work? What would be the problems w/ a Y?

And Rosconey, I used to have that exact thing. . .I sold it (I shouldn't have. . .). . .The thing is, all I need is to sum the signal. . . cheaply. That would basically be a waste as I would not use 90% of its features. I might have to go that route, though if this is a bad idea above.
p

scottnixon · « **Reply #9 on:** 24 May 2004, 11:40 pm »

You'll need a couple of resistors to sum the channels without monoizing the setup. I've used a couple of 39k to 50k , just add one in line with your cd R/L out into the mono'd/summed output.

pjchappy · « **Reply #10 on:** 24 May 2004, 11:43 pm »

So, monoing would be the only problem? It is going to 1 sub. Also, it would be coming out of the CDs analog outputs. I would use the digital output into your TubeDac+. . . this configuration wouldn't mono the digital, too????

Anyways, I may just go the more expensive route. . .can always sell it off when I don't need it. . .also, I think I may start a job in the next couple weeks.

p

audioengr · « **Reply #11 on:** 25 May 2004, 01:22 am »

Sorry - bad idea. The output drivers from your players or preamp will drive into each other. If they are low-impedance, damage could result. The best solution is a buffered summing device that does not load or otherwise compromise the front channels.

I have such a device in prototype phase. I need to drive my sub from both my 2-channel system (mixing left and right) and also from the HT system (from the SS processor sub outputs. This device will do this. It plugs into the L and R outputs of your preamp (has short cables attached)and then provides jacks for:

L out - to amp
R out - to amp
SS processor sub in - from SS proc.
sub out - to powered sub or sub amp

The gain difference between the HT and 2-channel system is set by first adjusting the powered sub volume for the 2-channel system. Then the HT sub volume is adjusted at the SS proc. along with all of the other surround channels. If you use a sub amp, then a separate gain control is needed for the sub output.

pjchappy · « **Reply #12 on:** 25 May 2004, 01:23 am »

Damn. . .

Looks like I'll buy that Behringer x-over. . . never should have sold it.

p

audioengr · « **Reply #13 on:** 25 May 2004, 01:26 am »

Too bad that ALL crossovers seem to kill the sound of perfectly good systems. I've modded some of these lately...

pjchappy · « **Reply #14 on:** 25 May 2004, 01:29 am »

I just can't believe there isn't a little box that would do this for me. . .the Behringer does WAY more than I need.

p

audioengr · « **Reply #15 on:** 25 May 2004, 04:39 pm »

There was a little box. It is the Snell active crossover. It is not too bad without mods, but can get better. I just sold a modded one to a guy in the Virgin Islands. You might try ebay or audiogon. The thing was $300 new. I'm sure they dont sell it anymore though. Until I come out with my sub buffer I'm not aware of anything cheap that is new.