Audio "gain staging" is easy when you know what to look for... The fact that a knob or slider is "almost all the way up" or is "nearly all the way up" is not relevant other than its an observation. Knowing where to set the knob or slider is what IS relevant.

Here's what I mean... a general rule of thumb when dealing with gain staging is that you should deliver enough signal from each device (starting at the source) so that the receiving device can comfortably deal with the signal coming in. That is, NOT too much and NOT too little signal. You want each "stage" of the chain of devices to do its optimum amount of work. NOT too much work, and NOT too little work.

Follow the signal flow.

Start with your CP40 STAGE and the unbalanced connection to your small format mixer. The smart sound engineer (in this case, this will be you) would touch the limits to know where they are and then work underneath those limits. It is analogous to entering a play room when you were a kid - if you know where the walls are and how high the ceiling is, you can run around in that room full speed and never bump into anything or bang you head on the ceiling. That is what you are doing with your sound. You are going to test the absolute maximum you will be able to put out (in the heat of battle) and you are going to ensure that even this amount of signal will not click you system.

Start with just the CP40 Stage and the small format mixer.
Turn the CP40 STAGE to the maximum amount you would ever use musically. You want that level to enter your small format mixer without clicking the INPUT indicator. That means - when your CP40 STAGE is all the way up and you are playing with the maximum amount of energy you can muster... that this will NOT clip your mixer. Ever. It is okay if the overload indicator flashes on and off, this is usually a few dB before clipping. You never want to see that light stay on steady... You want reach up and touch the ceiling but you want to make sure your forehead never runs into that wooden beam even when you are jumping as high as you can jump.

You can do this with all other components in the chain set at minimum output. No one wants or needs to hear you testing the LOUDEST you are going to play. You can do it with just the keyboard and the mixer with the mixers METER or Overload/Peak light. The mixer's main output can still be set to minimum for this portion of the Gain Staging. You GAIN STAGE with just the peak indicator on the mixer channel input.

Now you have absolute the maximum level you are going to be able to produce... back the CP40 Stage down a bit, (always leaving yourself some room to move up if/when needed). Some where between 3/4 and 7/8 of the way up is fine. This gives you comfort later if you need it, you know turning up will not CLIP anything (you've already tested the ceiling and even if you jump to maximum height you will not hit your head (headroom, seriously, its called headroom, for this reason...)

The input channels of your small format mixer will be happy. They will be getting enough signal to do a clean job of prepping the signal for the next stage of the signal path. The CP40 Stage will never Clip the small format mixer. See how that works? If you do not send enough signal to the mixer's channel, you will wind up using the PREAMP on the mixer to raise the signal... the penalty of not sending enough signal into your mixer's channel is NOISE... turning up a preamp will add noise... especially when you are doing so unnecessarily... Send more signal in, the mixer should not have to work hard at all, to be happy. Happy is getting enough signal IN so that it has little work to do sending the signal OUT to the next device in the chain.

Next, you want to raise the main output of the small format mixer which is connected to your powered speakers... I assume that the OUTPUT of the small format mixer is TS unbalanced going to your powered speakers - make sure the INPUTS on the powered speaker match the OUTPUT level rating of your small format mixer. If you are sending a LINE LEVEL signal from the mixer, set the Speaker's INPUT SENSITIVITY to match that rating. Make sure to consult any clip indicators on your mixer - you never want to see them, if possible.

Look for any help from the speaker in terms of incoming signal stregth... But typically when you have clean, gain staged signal exiting the source (mixer), and clean signal arriving at the powered speaker you can simply turn the level of the speaker up to fit the room compfortably.

Never turn a powered speaker all the way up, just so. That is not Gain Staging, that is Guitar player mentality (which does not work in pro audio situations), you turn the powered speaker up to the point where the audience can enjoy the music - never more than that. You want your system to sound like it is not even working hard, but is filling the room with clean loud signal. Clean and loud is tolerable to unbelievable SPLs... but if your speaker sounds like it is spitting up blood, and is harsh, even before you reach high SPLs your audience is getting ear fatigue. Clean audio goes louder because you want to listen to it...

The clean signal is guaranteed because you ensured that never TOO much was passed from one device to the next, sending TOO little will cause you feel like you must over compensate. Turn each device up in the order that it receives the incoming signal. Deliver the appropriate amount of signal to the next device in the audio chain.

Most novice audio folks work backwards... they start with the speaker and try to guess how loud to make it, then they sheepishly turn items up in the wrong order. There is a correct order to things when GAIN STAGING - just follow the signal from source to destination. And do not judge by HOW LOUD it is - the signal from the Keyboard to the mixer is not LOUD (you don't measure it in LOUDNESS... you can't hear that - LOUD is only a result of the transducers that turn electrons into air molecules in motion: SPEAKERS are loud) between the Keyboard and the mixer no air is moved, it is not technically LOUD, you are dealing with signal strength (GAIN). LOUD is always subjective. A perception of the human ear/brain. And you will set HOW LOUD to taste!

There is no LOUD between keyboard and mixer.
There is a transfer of signal measured in voltage and addressed as GAIN.

LOUD is subjective, so deliver clean signal to the powered speaker and turn the speaker up subjectively!

Make sense? Hope that helps... I use the analogy to make clear how you should think about audio.

Thank you Bad Mister for the detailed reply. I know a little about gain staging, but certainly not an expert. I forgot to mention something in my post, and perhaps it's relevant and perhaps it's not. When I look at the signal level meters on the mixer (several green LEDs, then a few yellow, then red if the level gets that high), I can hardly get even the first couple of green lights to register when using the CP40. Even with the output gain turned way up on the CP40, the signal level indicators on the mixer barely register even if I have the mixer's channel gain turned up a lot. To me, this seems wrong, as any other line level device I have going into the mixer has no problem registering plenty of signal level on the LED metering if I have the mixer channel input at unity gain and the input device (output from PC audio interface for example) turned only mildly up on its own output gain setting.

Greg

When I look at the signal level meters on the mixer (several green LEDs, then a few yellow, then red if the level gets that high), I can hardly get even the first couple of green lights to register when using the CP40.

The meters on the mixer are likely the output of the mixer. The step you want to check first is the step where the CP40 is coming INTO the mixer (I explained this above).

Does the mixer channel that you have the CP40 plugged into have a peak indicator?
Your first step is to make the output level of the CP40 make that peak indicator flash at the very maximum effort you are going to use to play.

The individual channel (or channels) you are plugged into on the mixer must have some kind of a GAIN control. Turn those up until your maximum play level causes the peak/overload indicator for the inputs to flash.

The meter that is green - amber - red is likely the output of the mixer (not the input of the channel)... which has nothing to do with gain staging the keyboard to the channel. .

Greg, two questions ...

What does the CP40 output level sound like through headphones?

Have you tried switching Performances (or checking the Volume and Gain settings for the relevant Part within the Performance you're using)?

m, if I turn the levels up pretty high on the CP40, the level though headphones can get reasonably loud. Not painfully loud, but plenty loud enough.

I have tried switching performances, but I have not gone into the menus and checked what the settings are for a particular Part. I have only turned the master volume knob up nearly all the way, and moved the volume slider up near maximum also.

Greg

Greg, I have a CP4, and don't know if its output levels are the same as CP40. For what it's worth, I can tell you that if I were to play the factory-default unmodified Performance 001 (Main voice CFX St) through headphones, I'd typically have the Master Volume level set at 12 o'clock. Much higher than that would be uncomfortably loud.

I normally run the CP4 directly into powered speakers, sometimes from the unbalanced outputs and sometimes the balanced, and never have a problem generating needed sound levels (in a jazz context, not playing rock), and usually have the Master Volume around 12 o'clock or a bit higher, and the speakers also around 12 o'clock.

I used to have a CP33, and typically used a small mixer. Haven't really needed that with the CP4.

Bad Mister,

I agree that my meter on the mixer is likely an output meter, and unfortunately the mixer does not have peak indicators on the individual channel strips. However, if I'm using one input channel only, and the EQ and Main Mix knobs are all set to 'Unity' so that they are not boosting or cutting the signal at all, then as I vary the channel's input gain I would think that the output meter will be essentially indicating the individual channel's input level, correct? I say this because in this case the entire output is just the one channel, and the EQ and Main Mix controls are not applying any boost or cut.

If this is correct, then I should then be able to vary the channel's input gain and use my output metering to check how strong my gain for the channel is and adjust it so that I am peaking only when playing the keyboard at the maximum effort. But as I said, when I do this, I can't get anywhere near a peak level, even when turning the channel's input gain way past unity. And every other line input that I use with the mixer, when used only one at a time, can easily register a strong signal at the output when the input gain is only at unity.

Greg

If you are using two TS cables (which I was led to believe by your original post) how is it they are in a single channel of your small format mixer? This would be fine if it is a stereo channel... since the small mixer has no peak indicator, does it have stereo channels?

If it is not a stereo input then that’s your reason. Summing a Stereo Signal to Mono degrades the sound significantly and should be avoided like the plague. All kinds of cancellation ensues.

Either maintain the stereo path or use only one cable connected to the Output labeled “L/Mono”.
Never, never sum stereo output to a mono Input, that’s would be wrong.

Sorry, I guess I could have been more clear about the mixer connections. The single channel strip on the mixer is indeed a stereo channel, with separate left/right input jacks. There is a single channel input level control which is applied to both the left and right input connections.

Looks like I'll have the opportunity to get another CP40 to check out at home, so once that happens I'll be able to see if its output level is any stronger or if it's the same as the unit I currently have. One way or the other I should know if the output level of mine is normal or not for this model.