sub to receiver connection question... (1 Viewer)

[PaulKH]

My receiver has two subwoofer output connectors (I guess to hookup two subwoofers if you have them - I don't). My subwoofer has two signal input connectors.

Today I have one of the receiver connectors connected via good quality RCA cable to a splitter at the end going into both sub input connectors. I think I heard somewhere that this was the way to go.

Any reason why I should not do what I'm doing or maybe send both outputs to both inputs?

Thanks!

 

[BruceD]

Sounds like you did the right thing, unless the sub outs say Left and Right, then you could connect two cables to your sub.

Unless your sub specifically states "for a mono sub connection use the left RCA" or maybe the right, then your solution is the best. In these cases the sub may internally mute or disconnect the other input.

Your solution (Y cable) eliminates the possibility of extraneous RFI getting into the other sub input.

BruceD

 

[PaulKH]

Thanks Bruce. On closer inspection, my receiver has no designation on the two subwoofer-specific outputs so I assume they're for two subs (can't find an explanation in the manual). The subwoofer itself does say left and right for inputs, and on re-reading the manual for it - they say to use a Y cable, so I guess I'm good to go.
My Y cable is pretty cheesy looking and seems like a weak link connecting it to the nice gold plated thickly shielded RCA cable coming from the receiver!
Oh well - just did a few more tests with Phantom Menace and it sounds good
I've just been experimenting with the receiver's EQ on the center channel specifically - I think it sounds better now on male dialog (which sounded lacking in higher frequencies).
I've also set all my speaker settings to small now and set the crossover on the sub to maximum (which the receiver manual recommends)...
This tweaking is endless, but worth it.

 

[BruceD]

Think I paid $10-$13 for a thick gold-plated Monster Y cable adapter (about 6" long) at Fry's electronics here in California.

BruceD

 

[Mark Rich]

Try a Monster cable's y-connector. Works better than a y-cable IMO. It has two RCA female connectors on one end and a male on the sub end. You can see whatthey llok like on the Monster web site. Others sell them too.

 

[Vinny Petronio]

Pual,
What receiver do you have? My parasound has two sub outs and I use them both I am running two MIT digital cables to my sub one on the left and the other on the right.

 

[Scott-C]

Paul and Others,

Your questions about sub connection inspired one of my own. Does your sub have a "LFE in" input on the back of it? Mine has one and I've connected my sub cable to it. With the sub connected this way, I've noticed I can't control the sub's volume level via the setting on my receiver (the connection may or may not be the problem here). I do get bass when playing movies, however, but I have to adjust the level at the sub, rather than on the receiver.

I could also connect the sub cable into the sub's low level stereo inputs using a splitter...what are the advantages and disadvantages of this type of connection vs. using the "LFE In" input?

Thanks!

 

[PaulKH]

> Does your sub have a "LFE in" input on the back of it?

No - mine has left/right only, but the manual explains how to hook it up either from main L/R outputs of a receiver with speakers hooked into it, or just from the subwoofer output of a receiver (without speakers connected to the sub in that case of course).

> With the sub connected this way, I've noticed I can't control the sub's volume level via the setting on my receiver

Well I'm assuming the volume is still going up/down in relation to your receiver's volume control - I guess you're saying you can't control its gain relative to the other speakers.

My receiver does let me control volume (gain) though.

> I could also connect the sub cable into the sub's low level stereo inputs using a splitter...what are the advantages and disadvantages of this type of connection vs. using the "LFE In" input?

Hmmm... don't actually know the answer to that one. Maybe contact the sub maker? Or RTFM?

 

[Randy Prue]

This thread seems to be the best place for the following:

My Harman-Kardon 520 has one low-level sub out (RCA female). The Veldoyne sub CHT-12has two female RCA inputs (it sums the two so the Y is "optional", except that the lack of signal on one side can cause the auto on to fail (I leave the sub set to on).

If the Monster Y has two females, then it would have to go on the receiver side (to give me two females for a standard male-male RCA cable to the two inputs on the sub.

1. Is it worth it? Since the sub sums the inputs, and it's working, why bother with a Y-connector?

2. I can also go pre-amp out from the H-K to the sub, then out from the sub back to the amp in (all done with RCA cable). Would this change the sound/performance of the sub? I'm assuming that this all needs to be done with yards of heavy cable.

3. I can also go main speakers out from receiver to the sub, use its crossover, then go main speakers from the sub to the actual speakers (also lots of wire).

If I do much more wiring, I will have to think about changing the cabinets that all this is in. As it is, the H-K has about 1/2-inch above it (open front and back) for ventilation, and it does get pretty hot. Alternate locations are all compromises (like a 17" unit on a 13.5" shelf, either defeating the H-Ks feet, or placing a wider board on the shelf.

Hmmm... I see why you need a forum.

 

[Scott-C]

Paul,

Thanks for the thoughts. I've posted a variation of this exact question in another thread; hoping I can figure out the problem. Yes, you're correct in that i believe the sub's SPL is moving in relation to the receiver's master volume, but I can't control it's gain via the receiver.

The manual, like many, is useless. All it says is to connect the sub the way I've connected it.

Thanks!

 

[BruceD]

Randy,

Just to be clear, the Monster Y comes in two versions;

1 female -> 2 males

1 male -> 2 females

I was talking about sub out from receiver with a standard mono RCA cable into the female input of the Monster Y adapter. Then you have the two male ends of the Monster Y to connect to your sub's two inputs.

Also, if you actually have an open RCA input on your sub (and the sub doesn't internally disconnect or mute it) RFI signals (interference) can cause problems with your sub.

Eliminating the input path for RFI is a good reason to use the Y adapter and provide input to both sub connections, especially on those subs with auto-on.

BruceD

 

[PaulKH]

Bruce, I think you're saying use a single male to dual female adapter on the receiver side. If so, this means running two long RCA cables to the sub. Why not just run ONE RCA cable from the receiver to near the sub, and into a single female to dual male adapter into the two sub inputs?

 

[PaulKH]

Scott - in cases where you don't have gain control for one output, the receiver manufacturer lets you adjust the gains for all the other outputs instead, which amounts to the same thing (although a pain).

 

[BruceD]

Paul,

Is this not clearly a single long IC cable (male on both ends) to a Y with 2 male ends for input to sub?

my previous quote:

------------------------------------------------

sub out from receiver with a standard mono RCA cable into the female input of the Monster Y adapter. Then you have the two male ends of the Monster Y to connect to your sub's two inputs.

--------------------------------------------------

If this was confusing, I hope this clarified it, as I was talking about the first Monster Y adapter I listed ;

1 female-> 2 male (about a 6" long adapter).

BruceD

 

[Randy Prue]

Bruce:

Thanks. Yes, I get it. As the last few posts describe, single cable to the 1 female > 2 males... the main thing is that they make a good Y connector to run one cable instead of two from the receiver.

Yes, they mention the problem of auto-on choking on the no-input side. For now, I taped one end of the RCA male pair that has nowhere to go on the receiver side. I think I also have a dummy male plug here somewhere, until I get the Y connector.

I just read the review of the Mission 70as that someone provided a link to. One customer did very thorough testing of it, and compares it favourably to the Boston Audio V600, which costs more. I liked the sound of the V600, so this is promising. I'd really like a musical, and physically small sub (did I mention cheap?). Another reviewer says he noticed a big difference with better cables.

 

[PaulKH]

Thanks Bruce, got it.

 

[Scott-C]

Scott - in cases where you don't have gain control for one output, the receiver manufacturer lets you adjust the gains for all the other outputs instead, which amounts to the same thing (although a pain).

Paul, are you referring to the speaker calibration process or an adjustment I might make mid-movie? If the former, I guess you mean I should use the sub's volume control to calibrate the sub to 75 Db using Avia, for example, and then use the gain controls for the main L/R, center, and rear to match them to the sub?

 

[PaulKH]

Yes, the former. Not that I'm any expert. But my receiver (and many others) doesn't let me change the volume level of just the front speakers, but it does let me adjust all the others relative to it I guess.

 

[Randy Prue]

I had a Kenwood ?? 509 that lets you adjust the front speakers, but... once you set it to (I think it's) subwoofer off, then the fronts become automatically (Large? Regular? Small?) and you can no longer access that menu, but you could still do the -db +db adjustment. I'm not sure, but I think that at times you could not access that menu either. As long as you lied to it about (probably the sub), you could get to the adjustment.

Adjusting the db up or down is part of tuning the surround, so it has to let you into that menu. You just have to read the manual 4 times and push all the wrong buttons until it works.