Hooking up main AND remote speakers

[qwertygnu]

Hey yall,

So I have this kinda old Onkyo tx-904 av receiver. It has 2 sets of speakers it can output to: 2 main and 2 remote.

On the back it says: "Main: 4 Ohm min/speaker" and "Remote: 8 Ohm min/speaker"

I have 2 4 Ohm speakers and 2 8 Ohm speakers. However, for each speaker (both 4 and 8 Ohm), it'll play at full volume when connected to a 'main' speaker port and much quieter when connected to a 'remote' port!

This post might have the answer but I don't see it...http://audiokarma.org/forums/index.php?threads/remote-channels-of-onkyo-tx-904-not-working.728838/

The goal is to have all 4 speakers playing the same thing, all at full volume. Right now they'll all play the same thing, but the speakers connected to 'remote' will play much quieter than the 'main' speakers.

thanks!

 

[swechsler]

The only safe way of wiring these would be in series, but due to the difference in impedance, the 8Ω speakers will almost definitely play quieter than the 4Ω unless they are vastly more efficient. I'm not aware of any receiver or integrated amp that is comfortable with a load of under 4Ω (you'd get 2.67Ω if you connected them in parallel), so if the series solution doesn't work, you're going to need a second amp (ideally an integrated amp with preamp in and out).

 

[onplane]

The goal is to have all 4 speakers playing the same thing, all at full volume. Right now they'll all play the same thing, but the speakers connected to 'remote' will play much quieter than the 'main' speakers.

thanks!

With your unit, I suspect you cannot achieve what you want to do. From the directions for the speakers, it's clear the remote amp is not as powerful as the main amp. That's why the main amp can handle 4 ohm loads, but the remote amp won't.

Remember the idea for the "remote" speakers is that those speakers are in a different room. Thus they were never intended to be played in the same room and so the differing gains of the amps was a non-issue as far as Onkyo was concerned.

You have two options to solve this problem:
1. Buy a 2nd integrated amp (amp with volume and tone controls)
2. Buy a unit like this one designed with 4 internal full range identical amps with separate volume controls for each stereo amp:

http://www.mcmelectronics.com/product/50-4640

Regards,
Jerry

 

[toxcrusadr]

I looked up the manual too:

https://www.de.onkyo.com/downloads/2/6/5/2/1/Manual_TX-906_904_EnDeFrEsNlSvIt.pdf

Which by the way was described in a Chicago Trib article about his receiver as really hard to follow. In any case, I can't see where it has two different amps for Main and Remote. Pg 5 gives the minimums ratings on the two outputs. Usually two sets of outputs (A and B they are typically called) are wired either in parallel or in series inside the unit. If in parallel, the manual will usually say minimum 8 ohms on each set of speakers so the parallel combination does not go below 4 ohms. Different ratings is very unusual. Also the amp specs do not list different L and R amps for main and remote. If I'm missing something please enlighten me.

It may be the remote outputs are just limited as a way of protecting the amps.

Another way you can do what you want is to get an impedance-compensating speaker selector box. It's more than just a switch, it has transformers in it to keep the overall load at 8 ohms regardless of what speakers you have or which ones are turned on. You'd connect this to one set of outputs (Main I would think) and hook up the speakers to the selector box.

 

[Messy Jesse]

I'm not sure if this helps, but I had a similar issue where my main (big) speakers would be too loud at the same volume that my outdoor (tiny) speakers were at the appropriate volume. I bought a stereo L-pad and built it into a small wooden cigar box with inputs on the back. It is wired to my main speakers. Now, when I have both on, I can bring down the volume of the mains without changing the impedance. I do sometimes worry about what I may be losing in signal quality. If I were to do it again I would build in a bypass switch so the signal can skip the l-pad altogether when not needed.

 

[onplane]

In any case, I can't see where it has two different amps for Main and Remote.

If I'm missing something please enlighten me.

It may be the remote outputs are just limited as a way of protecting the amps.

Hi, Tom! If you look at page 18 in the amp specs (and I agree it's as confusing as hell), but on the 904 column about half way down you'll see that the REMOTE amp is rated at 12 watts @ 1000Hz. In short, it's one of those little home theater satellite amps.

There is simply no way to get this amp to match the 60 wpc full range front amps. That's why I recommended he either buy an additional integrated amp or go for that Sherwood brute.

Regards,
Jerry

 

[toxcrusadr]

Mystery solved. Very weird setup IMO. I could see surround channels having lower wattage than the mains, but B or remote speakers usually run off the same L and R front amp channels as the A or Main speaker outputs. In any case the OP will never get the same power out of the remote outputs.

So, I would go with the impedance matching speaker switch to do what you're trying to do, and a remote volume controls for the remote speakers if you need it. That will maintain an 8 ohm load to the receiver.