How do I hook up a mono speaker?

Catoogie · Post by **Catoogie** » Tue Oct 13, 2009 10:04 am

So, I'm running a pair of Event 20/20 BAS off of my 002R and then a little pair of RCA/Radio Shack 'Auratones' and an old pair of 70's stereo speakers off of an old Kenwood receiver. I have another pair of the RCA/Radio Shack 'Auratones' and I'd like to use one as a mono speaker. How do I go about it?

Thanks

jgimbel · Post by **jgimbel** » Tue Oct 13, 2009 2:58 pm

L and R outs to a Y-connector? I've used them to take one signal and route it to two places, I don't see why you couldn't take two sources (the L and R channels) and make them one. That would be mono, wouldn't it?

The Scum · Post by **The Scum** » Tue Oct 13, 2009 6:35 pm

L and R outs to a Y-connector? I've used them to take one signal and route it to two places, I don't see why you couldn't take two sources (the L and R channels) and make them one. That would be mono, wouldn't it?

This is bad practice. A y-connector is fine to split one source to two devices. But to use it as a mixer is a bad idea - you're effectively shorting the device outputs to one another, which can be risky both devices...the outputs can work to fight one another, especially power amps where the output impedance is guaranteed to be low.

Sometimes it works alright for line level signals, ueually because the designers can bump up the output impedance enough that a short like that won't kill anything. But then you're at the mercy of the designer, with no guarantees as to how different devices are made.

There was an old HiFi "trick" to set up a center speaker, by connecting one side to the L output, and the other side to the R output (for example:http://www.fixya.com/support/t487236-ce ... _2238)...a quasi-bridged-mode, if you will...but thinking about it, this is actually listening to the side signal.

(consider how it works - current flows through the speaker, making sound, when the two channels are at different voltages. But by definition, the center, mono signal is the common signal in both channels - if something is panned to the center, the L and R Voltages will rise and fall together - no voltage difference = no current = no sound. So to do this trick to get real mono, you need to invert one of the channels...such that as the L voltage is rising, the R is falling...)

jgimbel · Post by **jgimbel** » Tue Oct 13, 2009 7:21 pm

Well there you go. Like I said I haven't tried it, glad he corrected me before you tried it, in case it damages your gear.

ashcat_lt · Post by **ashcat_lt** » Tue Oct 13, 2009 9:13 pm

The Scum wrote: There was an old HiFi "trick" to set up a center speaker, by connecting one side to the L output, and the other side to the R output (for example:http://www.fixya.com/support/t487236-ce ... _2238)...a quasi-bridged-mode, if you will...but thinking about it, this is actually listening to the side signal.

(consider how it works - current flows through the speaker, making sound, when the two channels are at different voltages. But by definition, the center, mono signal is the common signal in both channels - if something is panned to the center, the L and R Voltages will rise and fall together - no voltage difference = no current = no sound. So to do this trick to get real mono, you need to invert one of the channels...such that as the L voltage is rising, the R is falling...)

Naw, you use the + from L, and the - from R and I'm pretty sure it works just fine.

The Scum · Post by **The Scum** » Tue Oct 13, 2009 9:26 pm

Naw, you use the + from L, and the - from R and I'm pretty sure it works just fine.

Depends a lot on the amp.

Many power amps aren't balanced - they just drive the + terminal, and ground the -. They do this for 2 reasons: it's cheaper (need more power? they just add more output transistors, rather than doubling up all of the front end circuitry, too.) and it allows for bridged mono mode (because all of the active stuff is leading to the + output, so they just flip polarity on one channel, and hang the load between the 2 + outputs).

against88 · Post by **against88** » Wed Oct 14, 2009 1:08 am

you could set up a mono master fader and send it to an analog output of the 002 (3-8, not the master 1+2), send that to the R channel of a power amp. though i guess maybe its bad to only hook up one channel of a power amp? ...hmm better let someone correct me first.

better yet, find a mono amp. then you're done.

the finger genius · Post by **the finger genius** » Wed Oct 14, 2009 6:43 am

Please be gentle if I'm way off, but can't he just hook it up to either side and use the "mono" button on the front of the 002R?

edit: I guess you still run the risk of damaging a stereo power amp this way. Just pick up an old mono amp on eBay.

RefD · Post by **RefD** » Wed Oct 14, 2009 9:20 am

why not just hook up the second pair of Auratones normally and then stack them (one on top of the other) in the middle?

i've seen this done alot for mono monitoring and it seems to work well.

The Scum · Post by **The Scum** » Wed Oct 14, 2009 9:47 am

edit: I guess you still run the risk of damaging a stereo power amp this way. Just pick up an old mono amp on eBay.

If it's a solid state amp, there isn't any damage risk. They'll run all day with one output unhooked.

Though it is true for tube amps. Unloaded = verboten!

And a mono amp doesn't solve the OP's problem. He needs a stage somewhere in there that sums the L and R signals to make mono out of them. An amp with only one input won't do that...though with some clever hardware hacking, it wouldn't be hard to add.

I've owned a couple of old receivers with mono switches built in...my ol Marantz 2245 among them. The mono switch on the PT rig is a good idea, too.

why not just hook up the second pair of Auratones normally and then stack them (one on top of the other) in the middle?

As long as you sit far enough away that they form a single coherent image, that's a great idea!

ashcat_lt · Post by **ashcat_lt** » Wed Oct 14, 2009 10:03 am

A passive 2 x 1 mixer is nothing but a pair of resistors. Take your y-cable, put a resistor in series with the "hot" from each side, and you're done. A quick search would probably find you a good value to work with.

the finger genius · Post by **the finger genius** » Wed Oct 14, 2009 10:05 am

The Scum wrote:
edit: I guess you still run the risk of damaging a stereo power amp this way. Just pick up an old mono amp on eBay.
If it's a solid state amp, there isn't any damage risk. They'll run all day with one output unhooked.

Though it is true for tube amps. Unloaded = verboten!

Thanks for the info.

And a mono amp doesn't solve the OP's problem. He needs a stage somewhere in there that sums the L and R signals to make mono out of them. An amp with only one input won't do that...though with some clever hardware hacking, it wouldn't be hard to add.

The mono button on the 002R should already do this.

RefD · Post by **RefD** » Wed Oct 14, 2009 11:47 am

The Scum wrote:
why not just hook up the second pair of Auratones normally and then stack them (one on top of the other) in the middle?
As long as you sit far enough away that they form a single coherent image, that's a great idea!

3 to 1 rule should apply to this situation as well.

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How do I hook up a mono speaker?

How do I hook up a mono speaker?

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