Can I Run Live Vocals Through an Instrument Amp?June 6, 2008 10:16 am Live Sound
Many new bands want to know, can we just run our vocals through a spare input in one of our instrument amps when we play out, instead of buying and setting up a whole fancy-schmancy PA system? Well, my answer to this question is no, yes, and kind of. (How’s that for razor-sharp clarity?)
Most of the time, when we think about a high-powered onstage amplifier, we think about the guitar player’s amp. The thing’s huge! Why don’t we just run the vocals through that along with the guitar?
The main problem with this is that guitar amplifiers are purposely designed to not have a flat frequency response. If they did, they’d all sound the same! And yet we know that there is a “Marshall sound,” a “Fender sound,” and so on. It stands to reason that your vocals would sound markedly different if run through different guitar amps, and that can’t be good.
The electric guitar and its amplifier are best thought of as a single instrument. After all, an electric guitar makes very little sound without an amp! The frequency response and other sonic characteristics of the amp combine with those of a specific guitar to create a sound unique to that combination. This makes guitar amps great for guitarists, but not so good for vocalists.
Although guitar amplifiers do not have the flat frequency response needed for vocals, amps intended for keyboards (and also usable for bass) typically do have a flat response. These instruments are intended to be heard pretty much “as they are,” only louder. Have you ever wondered why some combo or practice amps are designated as “keyboard/bass” amps? It’s because those are the ones with a flat frequency response!
Running your vocals through this kind of amp will probably sound OK, although you might have to adjust the EQ (tone) controls on the amp to make it sound just right. This EQ setting may also affect the bass or keyboard running through the same amp, depending on the design. In this case, you will need to find a compromise EQ setting that is acceptable for both the instrument and the vocal.
3. Kind of
Even if you do have a keyboard/bass amp with a spare input that you can use for vocals, there are still a few shortcomings in this approach. For one thing, if you have multiple vocalists, you will need some sort of mixer to create a combined signal to send to the amp. But a mixer is one of the main components of that PA system you don’t want to buy! (The others are a power amplifier and speakers.)
A second factor is that the instrument amp, especially in a shared mode, may simply not have enough power to push that vocal up over all the other instruments (and drums). If you try turning it up to 11, you will get distortion.
Finally, the instrument amps are usually at the back of the playing area. Your vocal amp will thus be behind the vocalists, with the microphones pointing right toward it. Can you say “feedback”? I hope so, because you’re sure to hear it! With a regular PA system, the main speakers are positioned in front of the band, so you can turn the mikes up a lot louder before you get feedback.
So I guess my final answer to the original question is yes, you can run your live vocals through an instrument amp, but be prepared to do a fair amount of compromising with the overall sound.Tags: amplifiers, music technology, vocals -->