keyboards, any use to run them in stereo on a live pa?

earworm

New member
ok, so the band i started working with has keyboards in their setup,
they got the headphone output connected to a mono channel in their cheap mixing desk... thats something i never do in my homestudio,
but now i wonder,
whats the difference between headphone outputs and L+R outs?
are headphones unbalanced, but stereo,
any difference in volume, impedance, quality or whatever?

and i'll rather use the L(mono) out, run that to the mixer, only cause its a habit to use MAIN outputs instead of headphones-outs,

but do i need to run it in stereo, and pan hard L+R,
will that be of any use in a cheap/small live pa setup
(only vocal mics, keys, bass and guitar direct outs go trough PA, no drums)

or can i just save a channel and keep it in mono...?
 
Go for mono, for the most part. It's just easier to deal with. As always, the best is to try it, and see. But here are a few thoughts.


Running keys stereo can be fun. A stereo keyboard with a good organ sound just sounds cool, for instance. A lot of times the stereo/mono choice comes down to room and PA. If a lot of people are going to be outside the stereo field (which is shockingly small) they will not hear the opposite side. This can be offset sort of if the keyboard player is using an amp, and the room is small. It does have the advantage of leaving a nice hole for the vocals in the middle of the listening area, which can get overwhelmed by stage volume there. That's great until you get too far off axis, as the vocals can get overwhelmed by that side of the stereo feed.

The actual stereo field in a 15x30 meter room, speakers in the corners angled 45 degrees in, is about the size of a sofa, about 5-8 meters back. It gets narrower the closer together the speakers are. It gets a bit deeper as well, but the basic area size stays the same. Everyone else hears mono, pretty much. Think about monitoring stereo music on your home studio monitors. The place where you get good stereo is about the size of your head.

In fact, in just about any space, with any size PA, the size of the stereo field never gets much bigger than a sofa.

More than 3db difference in volume between the two speakers from the listener's perspective, and the ability to localize sounds accurately in the stereo field starts to be lost. (Stereo starts to disappear) More than 6db, the listener starts to strain to hear the other side, which can be fatiguing, as we do it unconsciously. At 10db difference, the other side is inaudible.

Also, at some distance, your head starts to treat the PA as one source. Stereo depends on things reaching your ears at different levels. Far enough away, and your brain can't seperate the two signals into left and right. They seem to come from the same point in space. Stereo becomes worthless.

Stereo can definitely make the keys seem bigger, and that leads to the other limiting factor- PA. You need to have enough PA to make it worth it. If all the "space" in the PA is taken up by keys so you can hear all those nice stereo subtleties, vocals can suffer. Sometimes thinner mono keys are the ticket to better sound. They still cut through without being overwhelming.

ps-headphone outs are powered outputs, just like speaker outs. A lot of line-level inputs can handle some signal from a headphone out, and for sure if you use a DI. Just be very careful. The signal will likely be pretty noisy, as the headphone volume must be very low so you don't damage the input of whatever you are going into.
 
If your keyboard has stereo effects and you want to take advantage of them, then you need to go stereo. Essentially, you are doing a sub-mix in the box.
 
I own a yamaha P80 digital piano, and it simply sucks if you only connect one side, because the samples are stereo, it just sounds very boxy when not connected in stereo. With my keyboards this is less of a problem, as the samples aren't so dependant on stereo. Just see if it sounds better when you connect it in stereo.

Stan.
 
stereo stereo stereo.... if you got an extra channel use it, it will beef up and widen your sound, there a high probability that your keyboard has stereo outs for a reason
 
Balanced connections

Use balanced connection......you loose 6db gain using unbalanced connection. You will notice a difference.
 
Hey, earworm

Well, being and old B-3 man I can sum it up in one word LESLIE!

Stereo is the only way, Helps with things like chorus, flange and reverb too!

That's how we do it in the 2 bands I play in. We do use a Mackie 1604 (Mine) in both but it's the same on any "All mono" mixer

We use Ch 14 and Ch 15. A quick tip too, Don't pan hard left and left right. Put them at about 75 or 80% marks. IMO that gives a better Leslie effect. It's basically the same in a mixer with stereo inputs like a 1642, but when you use a stereo channel you do only get 100% left and 100% right with no "Cross talk". That's why i like to do the 2 mono channel bit.

Oh, as far as the earphone out vs the line outs, the earphone outs might run a little hotter, which could be good or it could be bad depending if you want to overdrive the PA to get really dirty sound. (Personally I prefer using other ways to get the OD, like using a tube monitor amp and taking the outs from there, but that's a 'nuther story.

Later, alligator, and break a leg at your next gig!

Steve - 'da ol' Smokedog in Cleveland
 
Headphone output is for headphones, it will overdrive the input of the PA / DI. L + R outputs are the way to connect to a PA.

Connect the stereo to get the full sound of the keyboard. The only exception is if the keyboard had a (for example) L (mono) + R where you can get away with connecting only the L (mono) channel if short of inputs or using a mono PA, as the full sound comes out the (mono) channel if the right side is not connected. Do not connect the L + R outputs together to try to get mono, it will phase cancel the output and also drive the outputs against themselves. If you want a way to connect L + R outputs to a single plug you need to make up a combine box, image attached.

Alan.

View attachment 79162
 
From the perspective of the sound guy with a small mixer I default to mono, generally from the "Left/Mono" out if possible. But there are lots of things that get missed with just one channel or with two summed, like getting only the ping of a ping pong delay or only one side of a Leslie. On the other hand with piano in a rock band I'm likely to eq down the lows a bit so I like to take the right channel which is often biased toward the high keys.
 
Geez this is an old thread dredged up. If it is a mono PA system, it makes no sense to use stereo output from the keyboard unless the Left output when used by itself does not default to a L+R signal.
 
I use my rig pretty much only for live application. The way I use it is I have a old Yamaha KM602 mixer. I have a Korg Kross and a Casio XW P1 that I am playing. I run both keyboards out L/R each to its own channel on the mixer. I pan both lefts and both rights about 60% left or right . then I take the L/R outs of the mixer into a dual DI which converts them from 1/4" to XLR and has a ground lift switch plus a db level selector for each channel. The XLR outs go directly to two independent channels of the house PA. Monitoring is brought back into a monitor dedicated to me for just keys. It is a great full sound. Im sure the stereo effect is as described in earlier post but the depth and fullness and richness is greatly improved. If I am running into a Mono PA application, I take the XLR outs from the DI and run them into a Peavey KB4 amp (It has 4 channels), Lefts into channel 1, rights into channel 2, which allows me to compensate either on the mixer or the amp for weak sided tones. Then from the amp into a single channel on the PA. The Mixer also allows me to use open air headphones if I like as it is equipped with headphone jack with its own volume control as well as the KB4 does also. The open air headphones allow me to hear whats going on with the rest of the band while allowing me to adjust my own keyboard volumes to suit my taste without interfereing with the house mix. Walahh!!!! Works for me,,,,,,,,,,,!!!!!!
 
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