Logic Studio apps Macbook Pro 15 + Mainstage2... low volume issue


New Member
Hello people!

I play at a church, where two keyboards are connected to the PA system through DI Boxes.

I recently bought a macbook pro, connected a keyboard to it via midi, unplugged one of the 1/4 inch cable connected to the keyboard, plugged a Y-cable in the headphone jack of MBP, and connected the 1/4 inch cable there.

I tried playing thru the PA, but the volume was too low thru the system...
Also, the sounds came out all distorted...

Do I need an external sound card to work this out? What am I doing wrong?!

Doug Zangar

Regarding volume issues, you shouldn't need an external audio interface (although that can be better audio quality). If your computer and MainStage are configured correctly, it probably has to to do with your cabling, or how you've connected it to your PA.

Now, about MainStage and your computer. Regarding distortion, you may be clipping inside of MainStage. You'd need to look at your meters - also verify your output levels are set correctly. Also go to System Preferences>Audio and make sure your computer output volume is set correctly.
I have made direct comparisons of my electric bass, before and after connected to a direct box. With a passive direct box, the tone gets sucked out of the bass, so I never plug the instrument level into a direct box. My amp has a secondary line out, and if there are house mains, I use the secondary line out on the back of my amp to send a signal to the direct box. The tone (and the volume) is unaffected that way. Inserting a (passive) direct box between the bass guitar instrument signal and the amp (instrument level) input does not work for me, and most likely is the beginning of your problems.

Your cabling is unclear, maybe you meant to write something different, but help me understand what you are saying:

"...unplugged one of the 1/4 inch cable connected to the keyboard, plugged a Y-cable in the headphone jack of MBP, and connected the 1/4 inch cable there."

Did you mean the line in on your MacBook Pro, or did you really connect the audio out from your keyboard to the headphone out on your MacBook Pro? Assuming you meant to say to the line in, you need to boost the keyboard out level up to line level: the computer is not a pre-amp, it accepts line level output, not instrument level (20-40 db difference).

Signal flow will obviously create big problems. But jettison the Y-cable and change your direct box setup from interrupting the instrument level signal. Figure out a way to send a line level signal out to your house mains. You could just connect the line out from your computer to the direct box, and have the sound guy fold back that signal into the stage monitors. But you will still need a preamp to increase your keyboard instrument level signal output up to the line level input on the computer. If you have a preamp with a built-in compressor/limiter, that will help prevent problems with overloading the A/D converters in your computer.