How do you hook up your subs if it has 2 inputs?

 

New member
Username: Pwangdel

Post Number: 2
Registered: Oct-06
Greetings:

My RSW-12 sub has two sub-woofer input one in white color and the other one red.

I hook up my Denon AVR-4806 subwoofer output to my JBL HTPS-300 power sub input and from the HTPS output to the RSW-12 red input. Is this correct? Otherwise, which input should I use for optimum performance and bass?

Thanks in advance for your time and help.
 

Silver Member
Username: Mccambley

BREEZY POINT, NY USA

Post Number: 277
Registered: Jun-05
Use the white (left) connection on the sub. This a Mono connection for the sub, there is no need for stereo connection. On the Denon 4806 (nice receiver)use the PRE-OUTS (page 23 of manual) SW (sub woofer) to the sub white input, one RCA jack.
 

New member
Username: Pwangdel

Post Number: 3
Registered: Oct-06
Thanks for the info.

I was lucky and got this receiver on sale for $1000 at 6th Ave Electronics. Now I have to figure out if it is worth an extra $500 to upgrade the hardware to 4806CI.
 

Bronze Member
Username: Drgroovee

Portland, OR USA

Post Number: 21
Registered: Sep-06
Hi Paul,

It's not entirely true that the white input is THE input to use. True that using either will get you sound, but one may be better than the other and using both is often desireable. It depends on the amp and how it was designed.

Some (not all) of the amps that we use in our subs actually use the Right side input as the single sided input of choice. Backwards? Well, conventionally it is the left input that is known as the "mono" input. I'm assuming there are no markings on the sub to indicate which of the two to use.
You may benefit from the use of a y-adapter. You can get a well made y-adapter that adds little to no impedance in the signal path (for about $15). It's one female RCA to two Male RCA plugs. This allows you to use both inputs on your sub amp.
On some sub amp designs, this bridges the amplifier and boosts the output by about 3db. It's a nuanced improvement in most cases but one that I've found worth doing IF the sub amp performs differently. I would check with the manufacturer and see if they have anything to say about it.

Cheers,
Caleb Denison
Aperion Audio
Home Theater Guru
 

Gold Member
Username: John_s

Columbus, Ohio US

Post Number: 1152
Registered: Feb-04
Hello Guys,
First, let me say that I can't blame Paul for asking his question. I just looked up the RSW-12 Owners Manual, and after seeing what it had to say about hook-up I can understand why there might be some confusion:

"LINE LEVEL CONNECTIONS AND CONTROLS -- Using a line level RCA subwoofer cable, connect the Subwoofer/LFE/Low Pass Output of your electronics to the subwoofer via the RCA jack inputs on the subwoofers' rear panel. Refer to Figure 2. For more infromation on the controls mentioned in this manual and on bass management see your dealor or www.klipsch.com."

Fig. 2 is a joke. It is a crude drawing that sheds no more light on which input to use on the sub than the text does. Back when I was using a separate sub, I used a Y-adaptor such as Caleb says. My old sub's manual (Infinity) wasn't any clearer than this one on this issue.

All of which brings me back to a question that nobody has been able to explain in terms that I understand. Since the .1 or LFE output on receivers and pre/pros is mono, why do subs have what appears to be stereo inputs?
 

Bronze Member
Username: Drgroovee

Portland, OR USA

Post Number: 24
Registered: Sep-06
Hey John,

I think I can help here.

The line level stereo inputs (and corresponding outputs, usually) are there to allow more flexibility in hook-up.
Let's say that you had an older stereo pre-amp with no subwoofer output (Like a nice Dynaco Pas-3). To employ the use of a sub, you could run interconnnects from the stereo pre-amp outputs to the stereo inputs on the sub. Then back out of the sub and into your amplifier. Most subs apply a high pass filter so your amp will only get, for example, 70 hz and up. This works great if you have a pair of bookshelf speakers that you want to run with a sub and is a superior alternative to using long runs of speaker wire to connect to the high level (or speaker level) connections on a sub.
I also reccomend it in applications where you might want to run multiple subs. Rather than split the subwoofer output on a receiver, you can use the pre-outs for the left and right channel and run them to a second sub. I do this at home and it works great. Allows more control over your bass distribution, too.

Hope that helps!

Caleb Denison
Aperion Audio
Home Theater Guru
 

Gold Member
Username: John_s

Columbus, Ohio US

Post Number: 1153
Registered: Feb-04
Paul, I don't mean to hi-jack your thread. I think your question has been answered anyway. Hook up a female>2-male Y-adaptor to the end of your subwoofer line and that way you have both inputs covered on the sub.

Caleb, I appreciate very much your taking time to answer my question. I am still confused a bit, though.

The line level stereo inputs (and corresponding outputs, usually)

I have not made it a habit to check out every subwoofer I've seen, but every one I have either looked at or owned did not have line-level outputs. All had two line-level inputs, however. All the older subs (and maybe all the newer ones as well) had speaker level ins and outs, which was a holdover from the Dolby Pro Logic days when LFE outputs did not exist. Speaker level ins/outs were obviously necessary with passive or unpowered subs, which are now pretty much a thing of the past.

Anyway, am I missing something here?
Are line-level outputs now standard on modern subwoofers?

I also reccomend it in applications where you might want to run multiple subs. Rather than split the subwoofer output on a receiver, you can use the pre-outs for the left and right channel and run them to a second sub.

Sounds good Caleb, but even this application doesn't require stereo line inputs on a sub. You could combine the R/L output at the receiver or pre-amp with the aforementioned female>2-male Y-adaptor and run a single line to a sub's single line input. (I could be wrong, but I don't think this would overload the sub's input.)

It seems to me that whether a sub is being used to reinforce bass in analog stereo system or in a LFE signal surround system, the sub is mono. And except for the extremely unlikely "loop through" scenario you describe, two inputs on subwoofers don't make sense to me.
 

Bronze Member
Username: Drgroovee

Portland, OR USA

Post Number: 27
Registered: Sep-06
Hi John,

It was, perhaps, misleading of me to say "corresponding outputs, usually" because that does insinuate that it is common when only about 25% of subwoofers seem to offer this feature. It's something that is commonplace with Velodyne's subs and can be found in Polk's higher end subs like the PSW-1000- of course, we also utilize an amp with this feature. So... to say it is standard would be inaccurate, but it seems to be gaining popularity, especially since the same BASH style amps are becoming more prevalent and they usually offer the line outputs.

Also, you wrote:
You could combine the R/L output at the receiver or pre-amp with the aforementioned female>2-male Y-adaptor and run a single line to a sub's single line input. (I could be wrong, but I don't think this would overload the sub's input.)

To respond: Oddly enough, this isn't true. One can't combine a left and right output signal through a Y-adapter. We learned this the hard way through trial and error whilst playing with multiple set-up configurations here at our lab.
Also, if you run any signal from the front left and right pre-outs on a preamp or receiver (as we often do ourselves and reccomend to others) the sub signal is not mono, but in stereo with bass signal not necessarily equal between the two channels. Some jazz recordings have the upright bass placed entirely on the left channel while the drums (including the kick drume) are faded to the right channel. Sonny Rollins' Way out West SACD is like this.

So, while not commonly needed, I think that the stereo inputs and the outputs have their place for some of us. Certainly, most folks don't need it and I can see that, from a setup standpoint, things might be a little more intuitive with a simpler amp. I guess we just like to make sure folks have all the options at their ready.
 

New member
Username: Pwangdel

Post Number: 4
Registered: Oct-06
Thank you all for your valuable input.

John S, not a problem. I am glad that you've brought up a good point.

Caleb: Many thanks for taking your time to explain this.

Please correct me if I am wrong. Basically, I am able to run the sub-out from 4806 to one sub and run the front left & right pre-out from 4806 to other sub. However, both of my sub has two inputs (JBL has line level inputs) will it be better to use Front Left pre-out for JBL and Front Rigth pre-out for Klipsch rather than the sub-out? If so, how do you control the bass through your receiver?
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