Converting stereo to mono

Forums › Home Theatre (including HTPC and EPG Collector) › Converting stereo to mono

bazzer

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#96049 19-Jan-2012 07:57

I'm running some outdoor speakers through the Zone 2 output on my receiver. The trouble is that they are quite far apart, to cover my whole deck. They do a decent job, but being so far apart there are obvious issues with stereo sound. I thought that it might be better if I could get mono audio out of them, but not sure how to proceed? I don't think my receiver offers anyway to mix down the inputs to mono so my choice is to do it myself I guess.

All my sources are digital, but I generally use my PS3 analog out as a source for those speakers (HDMI out for the indoor speakers) so I figured I could do something here? Is it possible to get some kind of passive adapter to mix the L/R from the analog out into a passable mono output? Furthermore, the Zone 2 input is 2-channel so I imagine I need to split the mono output into two identical mono outputs to feed the Zone 2 L/R inputs.

Essentially, it feels like I'm after a way to take L/R output and convert it to 2 identical mixed mono outputs. Does any of this make sense, or am I over thinking it?

The research I've done suggests using Y-adapters 2 -> 1 -> 2, but while this might work, it doesn't seem that great a solution to me. The quality doesn't have to be great, it's just for background sounds outdoors. I don't mind building an adapter if that's the way to go, the bonus would be I could make it switchable stereo/mono as sometimes I'm in the sweet spot where I can get a decent stereo image and might like that over the mono but not too fussed.

richms

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#570715 19-Jan-2012 10:47

Dont combine speaker level signals like that.

if it doesnt support a mono output then the only option you have really is to take the line output, combine it and then put that into another amplifier.

However most recievers are really cheap and dont buffer the line outs, so if you just combine them together with a Y cable then it will effect other stuff as well. May not be a problem as you dont use the other analog line outputs. I had a reciever that was so cheap with its inputs that you could use the tape out sockets as an input that would mix with the currently selected source, and grounding them out (like a tapedeck that is powered off does) would noticiably lower the audio levels.

For my outdoor speakers I am using a couple of dirt-cheap "motorcycle" amplifiers off DX running from the tape out of the reciever, mine is old so I only get analog sources coming out the analog outputs which is a pain. They are just cheap class T amps which take 12v and have a volume control on them. 20 watts or so which is enough to bother the neighbours.

Richard rich.ms

bazzer

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#570725 19-Jan-2012 11:04

I might not have made it clear, I definitely intend to do it on the line level analog output from the PS3 rather than doing anything speaker side. I don't use the analog out of the PS3 for anything else either, so you think it would be OK just to use a y-cable to mix it, then another y-cable to split it to dual-mono?

I thought that the outputs were low impedance so might cause issues? I was thinking about knocking up a simple resistor network but do you not think this would be necesary? I suppose the only real consideration is damage to the PS3 output? My receiver is a Denon AVR-2308 if that makes any difference (i.e. not complete junk).

wmoore

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#570731 19-Jan-2012 11:27

If they are just been used for background sounds personally I would leave them as stereo.

"In the end, it's not the years in your life that count. It's the life in your years." -
-- Abraham lincoln

richms

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#570738 19-Jan-2012 11:37

There is a resistor on the output of about 1k normally for a proper line out, you can short a line level output and not damage anything by design. Its not a perfect mix job just combining them with a Y (I cant remember the electrical reason but it was to do with dB's etc) - its the headphone outs that get upset when you start to do things with them.

very worst case is you overload the analog outputs and start to get clipping etc. Check your dollar store out for Y cables, they have both 2 male to 1 female and the other way around, I was horrified at what the ones at DSE cost back when they actually did sell useful cables and not just TV's

Richard rich.ms

Jaxson

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#570741 19-Jan-2012 11:40

richms: Check your dollar store out for Y cables

Good point, we've got one with the weirdest collection of patch cables and the like, but super cheap!

bazzer

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#570788 19-Jan-2012 13:02

wmoore: If they are just been used for background sounds personally I would leave them as stereo.

Which is what we've been doing, but if you're down one end of the deck and you're listening to something with strong separation (think Beatles albums with the various parts hard panned) it's not as enjoyable. I guess I'll give the Y-cable's a go and see how I get on.

Loismustdye

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#572743 24-Jan-2012 13:43

What might work is a cable by Griffin. Do a search for the "griffin cable for djay". Ubertec sells them too.
ITs a Y cable made specifically for the djay app used on the ipad/iphone. It plugs into the 3.5mm headphone jack and splits the stereo signal into left and right channels, each on their own 3.5mm cable. then just plug 3.5mm adapters at each end for plugging into AV gear.
Costs around $30.

http://www.ubertec.co.nz/main/product/29768.html

Although after reading your post again they may not be what you want.

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bazzer

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#572760 24-Jan-2012 14:20

Thanks for the hint. My guess would be the iDevice is mixing the master audio down to mono itself and outputting it on one of the stereo channels, while using the other for cueing up. Neat idea though.

Skolink

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#573156 25-Jan-2012 13:28

If you just connect the stereo outputs with a Y cable the result will be an average rather than a summation of the signals. The voltage on the combined output will be pulled to the midpoint between the two stereo output voltages. I'm not sure how that would affect how it sounds, but that's what would happen 'electrically'.

Can't you just set the PS3 to output mono?

bazzer

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#573161 25-Jan-2012 13:43

Skolink: If you just connect the stereo outputs with a Y cable the result will be an average rather than a summation of the signals. The voltage on the combined output will be pulled to the midpoint between the two stereo output voltages. I'm not sure how that would affect how it sounds, but that's what would happen 'electrically'.

Can't you just set the PS3 to output mono?

I stand to be corrected, but I don't think that's possible. In any case, it would be a hassle (albeit one I'd be willing to accept if I absolutely had to) because I'd have to change it to/from mono whenever I use the speakers outside. Plus, if I'm listening simultaneously inside I'd only have mono sound.

An average rather than a summation is OK, isn't it? The average is just half the sum, so won't I just have to bump up the volume outside to compensate?

Skolink

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#573295 25-Jan-2012 21:01

bazzer: An average rather than a summation is OK, isn't it? The average is just half the sum, so won't I just have to bump up the volume outside to compensate?

Hmmm so it is. Should work just fine then.