If your keyboard doesn’t have onboard speakers and you want to share your playing with others, you can connect your instrument to a number of different devices or speakers. The main requirement is that the other device must have its own power source.
Here’s a general rule for turning electronics and audio gear on and off when connected to a separate amplifier, powered speaker, or whatever: With both devices off, always turn on the sound-producing item first. Then turn on the amplifier/powered speakers.
This order ensures that any pops or wake-up sounds the device makes don’t go out your speakers. When shutting down, turn off the amplifier/powered speakers first, followed by the sound-producing item. First on, last off.
Connecting to your home stereo
All home stereo systems include some form of additional input, usually labeled as an AUX or Auxiliary input and sometimes Tape input. Home stereo audio/video gear commonly uses a different type of connector called an RCA plug, which has a small, thin plug connector surrounded by a metal shield.
These plugs are mono, which means you need two cables to connect to your home stereo/theater device.
Here are the most common situations for connecting:
If your keyboard has two 1/4-inch line outputs labeled L/Mono and R (left/mono and right), you need two cables that have male mono 1/4-inch plugs on one end and male RCA plugs on the other.
If your keyboard has a single stereo 1/8-inch jack (labeled as an output), you need a special type of Y cable that has a male stereo 1/8-inch plug on one end and splits out into two cables with male RCA plugs.
If your keyboard offers no jack labeled as an output, you can use the headphone jack to connect to your stereo. If it’s a 1/4-inch jack, you need a cable with a male stereo 1/4-inch plug on one end that breaks out into two male RCA plugs on the other. This Y cord is readily available in musical instrument stores and online.
Use a cable long enough to make the connection without requiring adapters or additional connectors. These items can weaken the signal and make noise.
When you’re armed with the correct cables, here’s how to connect them:
Make sure both devices are turned off and their volumes set to 0.
Connect the L output of your keyboard to the L AUX In and the R output of your keyboard to the R AUX In.
Turn on the keyboard first, waiting until it has fully powered up before moving on.
Set your home stereo to AUX and then power it on.
Bring the keyboard’s volume up to around 50 percent.
While playing some notes on the keyboard, slowly bring up the home stereo volume to around 10 to 25 percent.
If you need a little more volume, go back to your keyboard and raise its output slightly.
Using your computer speakers
Computer speaker systems can range from sounding okay to very good. These speakers usually accept a single stereo 1/8-inch plug. The easiest connection is if you have a stereo 1/8-inch output or headphone jack on your keyboard. Then you only need a long cable with a stereo 1/8-inch plug on each end. If that isn’t available, here are the two other common scenarios:
The next easiest connection is to use the stereo 1/4-inch headphone output. This option requires a male stereo 1/4-inch plug on one end with a male stereo 1/8-inch plug on the other.
You can use the two 1/4-inch main outputs if you really want to, but this strategy is the least desirable of those presented here. To go this route requires a Y cable that joins two mono 1/4-inch plugs into a single male stereo 1/8-inch jack.
Plugging into amps and other 1/4-inch jack devices
The main thing you need to know is whether the device is stereo or mono. Many keyboard and guitar amplifiers you find in a musical instrument store are mono. If you have only one powered speaker, you’ll be playing in mono.
Your keyboard always sounds better when connected in stereo, but if you have to, you can listen to it in mono. Some better keyboard amps are stereo devices; even if they have only one cabinet, they still have dual speakers inside.
These amps are better for keyboards than a mono keyboard or guitar amplifier. In the case of powered speakers, you can always buy and use two separate speakers to fully reproduce the stereo image your keyboard delivers. And you could always plug the right channel into one guitar amp and the left into another.
To connect in mono, use the line output labeled L/Mono. This output treats the internal signal properly for listening in mono, so you don’t lose any of the frequencies or information. This output is almost always a 1/4-inch jack, so use a common male 1/4-inch to male 1/4-inch instrument cable, sometimes referred to as unbalanced or guitar cables.
Some smaller portables and digital pianos with onboard speakers don’t have line outputs, so your only choice is the headphone jack. In this case, you need a cable that has the matching connector to your headphone jack with the mono 1/4-inch plug on the other end.
If you need to use a PA system, connect your 1/4-inch line outputs to two channels of the mixer, which always has 1/4-inch jacks. Two normal line/instrument cables will do. Locate a control called pan and set one channel all the way left and the other all the way right so your sound comes out of both speakers in true stereo.
Some mixers have stereo channels, which simply means that one channel can accept two 1/4-inch inputs and doesn’t need the individual pan control(s). It will have a knob called balance, which should be kept straight up.