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elguezio · Joined: 08 May 2012 Posts: 11 Location: San Diego, CA

Hello everyone! This is my first post on this forum. I bought the M50 a little over a month ago and have been playing it constantly, both solo and with my band. I've also been slowly but surely working my way through the instruction manual.

I'm a very technical person with a degree in computer science, and a job as Director of Technology at an Internet company, but a lot of the manual is over my head given my very limited background in sound engineering. So I have a ton of questions.

My first and biggest question is what's the deal with mono output exactly? A lot of the programs are clearly in stereo with different sounds going to different speakers. When I play at home this is fine as I have it hooked up to my home theater receiver. But when I rehearse or gig I'm only using the mono output either to the band's PA or the venue's DI.

Do I really need to run two quarter inch cables in these situations in order to get the full sound of each program? When playing at a venue I don't want separate sounds to go to separate speakers since the crowd is all over the place. How do I force the M50 to down mix the stereo channels to a mono output across all programs?

I'll table the rest of my questions for now but if anyone could recommend any helpful tutorials on the M50 for a total noob I'd be super appreciative. Thanks in advance!!

billbaker · Posted: Tue May 08, 2012 7:00 pm Post subject:

There are stereo outs L/R on the rear panel. One (the left?) should be marked "mono". Using a single 1/4" cable should get you a summed mono version of sounds even if they are nominally stereo by design. Use the one marked mono - since using the next one over will get you half a signal, the right side only of the stereo signal.

The headphones will still have the stereo sound and if you were recording (vs.live) using the two stereo outs would be standard way to set up.

But live setups (non-DJ) are rarely, if ever, run in true stereo, rather each side is divided hi-low or hi-mid-low running the same signal to both sides in mono. Unfortunately, this means that stereo samples or cool panning effects are less than satisfying in the context of that live mono mix than they are in your headphones or home studio.

Any perceived stereo image on stage is more due to stage placement and and each instrument's playing volume than any planned sound design inside the instrument itself. So having a small monitor to give some locational feel on stage is ok, but be aware the sending the left to the front of house mains and the right to your monitor will not give you the best results - consider: the top half of your piano on stage and the bottom half going to FOH? Not good.

You'll have to think about how you want to route your audio signal (and exactly what it is) in order to achieve your best sound playing live.

BB
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billbaker

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elguezio · Joined: 08 May 2012 Posts: 11 Location: San Diego, CA

Thanks so much for the prompt and thorough reply! I just want to make sure I understand you correctly, though:

michelkeijzers · Posted: Wed May 09, 2012 6:54 am Post subject:

Afaik the headphone always outputs true Left and Right.

The Left and Right output depends on what is connected:
1) Both connected: output is both left and right (separate) signals
2) Only L/Mono connected: output is a mixed down L/R signal
3) Only R connected: output is only right channel
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Ajbbklyn · Posted: Wed May 09, 2012 12:13 pm Post subject:

Exactly as Michel says.

The easiest way to think about the audio signal is to use the metaphor of a river.

L/MONO = The left+right tributaries flowing into a single (mixed mono) river.

Some prefer to wait until later in the chain to mix the L+R signals together so that the board feeds a stereo signal to an outboard stereo effects pedal. One example would be a rotary speaker simulator, such as the BOSS RT-20 or Neo Ventilator. This configuration allows use of the outboard effect to full advantage by having it process a stereo signal - in stereo.

The signal is then combined to mono further "downriver" by feeding the post-effect stereo into a D.I. box and mono out therefrom.

Hope this helps.
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Pincho Paxton · Junior Member Joined: 22 Oct 2011 Posts: 65

I may be wrong, I'm not an audio technician or anything. But I think that there is some missing information in this thread. The jack-plugs for mono are especially made to pickup both signals from the left output. Take a look at the two jack-plugs, mono, and stereo.....

http://en.wikipedia.org/wiki/File:Jack_plug.png

As you can see, the mono jack doesn't use Number 2, the right hand signal. It combines both together.

Just in case you were thinking of using a stereo jack-plug in the left channel. Or I may be wrong. But I think you have to use a mono jack-plug in the left channel.

Ajbbklyn · Posted: Wed May 09, 2012 1:42 pm Post subject:

When both outputs (L+R) are used, "L/Mono" will only put out signal information from the left channel (as Michel has stated). When used as the sole output, it will put out the combined (summed) mono signal of L+R with information from both channels.

This is why the output is labeled L/Mono - it is a left channel when both outputs are used. It is a mono mix output when used alone.

The M50, like many pro keyboards, is wired internally to facilitate this functionality. The only connector that should be used for this output is a TR (mono) ¼" plug.
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elguezio · Joined: 08 May 2012 Posts: 11 Location: San Diego, CA

Thanks everyone! This definitely answered my question.

highpass · Joined: 15 Mar 2012 Posts: 6

Hello everyone!

I've got another question in connection with this issue:

If I use both plugs (L+R) to put the stereo signal into a mixing device, of course I also need 2 different input channels at the mixer.

How do I have to adjust the pan of each channel to realize a similar stereo image at the PA as I have i.e. in the headphone (plugged to the M50's headphone plug)?

Do I have to put the L-channel pan fully to the left (R-channel accordingly) or do the pan control knobs have to be in the middle?
Or what is the correct adjustment?

Thanks a lot!

X-Trade · Posted: Fri May 11, 2012 7:56 am Post subject:

Yes, fully left and fully right will give you complete stereo separation, which is technically correct.

In a live situation if you have a lot of extreme panned stuff, sometimes you will go for a lesser width so that people at both sides of the venue can hear everything, so you might go for 50-75% each way, rather than full-on
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dimitra · Joined: 05 Jun 2012 Posts: 27 Location: Bangalore

I'm using M-audio AV-30 monitors with my new M50.
http://www.m-audio.com/products/en_us/MAudioAV30.html
These monitors came with a stereo 1/4 jack to dual L/R RCA plugs cable. I have currently plugged in the stereo 1/4 jack to "Headphones" socket on the M50. I read in the manual that the audio output is the same whether you use the L/MONO + R sockets (with 2 mono 1/4 jacks) or the headphones. Just wanted to check with experts if I'm doing something wrong here. Would the signal levels matter?

billbaker · Posted: Mon Jul 09, 2012 1:32 pm Post subject:

Signal levels matter only insofar as the stereo image may put more emphasis on bass in the left channel (as with a piano). So you might find that one side or the other needs to be turned up to give you a more balanced image... i.e., equal volume in each speaker.

In many ways its easier to run a stereo PA as a one-man band than as part of a larger group. this seems to be what you're doing with the two monitors. You don't have enough info for me to tell how you'd get that to front-of-house, which is probably a mono mix. Whatever your situation, in order to run a true stereo image your PA has to be set up to provide that - most PAs don't, preferring to split the signal hi/low in mono for amplification efficiency rather left/right.

Headphone out is not generally recommended - but if you do use it check to see that you are plugging in a stereo cable (R-T-S - look for two black lines) to get both sides of the signal in a Y-split cable.

BB
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dimitra · Joined: 05 Jun 2012 Posts: 27 Location: Bangalore

Hi Bill, I'm performing at home, and using a pair of studio monitors. There no PA involved... the monitors are powered, and have a built in amplifier. I have connected the headphones out to the monitors instead of the regular line out. I was wondering if the audio output is the same for both headphones out and line out?

SanderXpander · Platinum Member Joined: 29 Jul 2011 Posts: 2220

I've never seen or heard any sound guy turning my left/right stereo signal into low/high dual mono. It seems to me it would sound a lot better in that case to just use a properly EQd single mono signal.

Also, as a side note, the Neo Ventilator actually only takes mono signal, even though it outputs a stereo one. This is no issue though, as the "stereo" part of an organ sound is the leslie that the Vent is providing.