Hooking sub (2 wires) up to reciever (1 wire) (1 Viewer)

[Guticb]

Long story short, I bought an RCA home theater kit about 3-4 years ago (Probably more, it's old) and the reciever decided to die on me at our Christmas party a while back. I bought a new Onkyo reciever (TX-SR-304) and am more than happy with it, with one exception.

The old reciever that died on me used two wires to hook up the subwoofer (I"m assuming a positive and negative?) as can be seen below:



However, the Onkyo uses one wire to hook up the subwoofer:

(Purple one, far bottom right corner)


My quandary is this: Does anyone know HOW I can hook up the old RCA sub to my new Onkyo reciever?

 

[Clinton McClure]

Hello Bojan and welcome to the Forum!

What you have here are two different methodologies. The two wires are high-level or speaker-level connections.

The new receiver uses a low-level RCA cable to send a signal to the sub.

Unless the sub has an RCA jack on it, you will need to find a high-level to low-level converter. Problem is, the only ones I have ever seen are for car audio and require -12vDC to operate.

If the sub has a set of inputs and a set of outputs, you can hook it up by running the front left and right speaker wires from the receiver to the sub's inputs, then running a set of wires from the sub's output to the front left and right speakers. If it's made like most package stereos, or HTIB's (Home Theater In a Box) however, there's no output on the sub and you may be out of luck.

 

[Ed Moxley]

You need a "Powered" sub, to plug into the Onkyo input........

 

[Joseph DeMartino]

I have that same receiver - and indeed, it has no speaker-level outputs for the sub, only an RCA connector for a powered sub. So your options are to wire your sub in-line with the front speakers, as Clinton outlined, or (if the sub has no line-level outputs) buy a new sub. I'd recommend the latter. Even a modestly-priced powered sub will make a world of difference to any HT system.

Regards,

Joe

 

[Guticb]

Thanks for the replies guys!

So would it be safe to simply plug those two wires into the same plug on the receiver as the Center speaker? (5.1 setup btw)

 

[Clinton McClure]

Probably not a good idea.

I'm assuming the center channel is 8 ohms and we would have to hope that the sub is also 8 ohms which would make the receiver see a 4 ohm load on the center channel.

The receiver would try like crazy to supply power to overcome the 4 ohms of resistance and will fail if it is not 4 ohm stable on the center channel, which it is probably not.

Besides, most LFE is sent either to the .1 sub channel of the main left and right front channels.

A powered sub is really the only good option at this point.

 

[Robert_J]

You can always add an amp to turn your current passive sub into an active one. Parts Express carries about a dozen plate amps as well as a few stand alone amps that are designed to power subs. Here is one example - link.

-Robert

 

[Guticb]

How much would a powered sub run me?

I'm not exactly willing to spend very much money ($50 at most).

 

[Ed Moxley]

You might find something on Craig's List for $50, but won't be easy to find anything decent.

 

[Joseph DeMartino]

If your budget is $50, your best bet is used equipment. Even an entry-level powered sub is going to run closer to $100. If private sales through Craigslist and eBay make you nervous, you can check out the used equipment being sold through Amazon.com.

Adding a powered subwoofer is the single most dramatic change you can make to a surround sound system, even more than upgrading your front speakers or receiver. The added punch is much more obvious that the sublter benefits of the other upgrades. If you can find a few extra bucks in the budget you might want to consider this Velodyne - a perfectly decent sub* that normally retails for $150.00 plus shipping and is now down to $85.00 - basically an even $100.00 delivered.

Otherwise see what you can find used and in the meantime you'll have no sub at all to go with that nice new receiver - which is a bummer. Good luck.

Regards,

Joe

* I've never auditioned this model, but I've heard a number of other Velodynes and I think they are quite good, especially for the money.

 

[Guticb]

I'll check that one out. I'll put it on my wishlist and start saving up for it. =P

Thanks for all the help everyone! Y'all have been great!

I definitely know what forum to turn to if I ever need home theater help. =]

 

[Nomad]

Dont waste your time with a $50 sub. You wont be happy. Save your $ a little longer. You dont have to spend a fortune. I found a brand new in the box powered 250 watt 10' Infinity sub for $249 with full warranty. It does everything I want it to. I have it set fairly low because if Im playing music I only want to hear exactly what was laid down on the track by the artist.
I have a nice pair of speakers but without the sub they lack the extra body the sub provides. My music is now a seamless sound that Im amazed at everytime I listen. For movies your going to get your $ back in the extra experience a sub will provide.

Also check out all the pawn shops in your community, barter with them. There are some good deals.
$50 wont get you where you want to go so wait.

 

[Joseph DeMartino]

Yamaha 8" powered sub - $130 new, $55 used at Amazon.com

Regards,

Joe