Many home musicians start off playing the electric guitar and so will probably already own a guitar amp. But with the name ‘guitar’ amp does that mean that it can’t be used for anything apart from a guitar? Could we perhaps use a microphone through a guitar amp?
The short answer to this question is that yes, you can use a microphone with a guitar amp but the quality will not be ideal.
There are a few reasons why using an amplifier designed for guitar is not ideal for a microphone and vocals and in this article, I will explain why, along with some other related frequently asked questions.
Why might you want to use a microphone with a guitar amp?
If you are just starting out in a band and you already own guitar amps then it is a quick way of being able to amplify a microphone. You already have the equipment available and you don’t have to go and spend lots more money on specialist equipment when maybe all you want to do is have a jam or practice together.
When I first started in a band we did exactly this. We used a small guitar amp to amplify our lead singers vocals, just so we could hear him over the other instruments. We knew that when we would come to play a gig that the bar or venue would have it’s own speaker system. You are pretty much always expected to provide your own guitar amps and even drum kit but you are almost never asked to provide a speaker system for vocals and so investing in your own system to simply practice at home may not be that wise if you can just use a spare guitar amp.
What will it sound like?
The clue is in the name that ‘guitar’ amps aren’t designed for use with a vocal microphone. For this reason, the pre-amps within the amplifier are made to make a guitar sound good and will therefore likely make vocals sound slightly distorted and generally a bit rubbish.
This problem of bad quality and distortion will only increase as the volume is increased.
Another reason it won’t sound that great is the frequency range of the amplifier. With the human voice, when you sing, you don’t just sing a single frequency the note will be full of a range of harmonics ranging from quite low bass frequencies up to much higher ones. A guitar amplifier is not designed to emphasize those lower bass frequencies (that is why we have different bass amplifiers) and so you won’t get the full rich tone of the vocal part coming through the guitar amp.
Could a microphone damage a guitar amp?
There is always a chance that when using two pieces of equipment that aren’t designed to go together you may cause some damage. If you get too close to the amplifier it can cause some pretty bad feedback, which could in rare circumstances cause damage or even blow a speaker.
It is unlikely that this will happen though. A guitar amplifier is designed for playing loud and it should be fine. Just be careful to treat the amp well and not plug in or unplug the microphone when it is turned on and don’t turn the volume too loud and you shouldn’t cause any damage to the amp.
How to Connect a Microphone to an Amplifier.
Now you know that it can be done how do we go about doing it? Well for this you will need to purchase a specialist cable. The reason for this is because the output from most microphones is ‘XLR’ whereas you will never see an XLR input on a guitar amp. A guitar amp will almost definitely have a 1/4 inch instrument input. This is why we need the cable shown below which has a female XLR to 1/4 inch connection.
Unlike a 1/4 inch instrument cable which is identical at both ends, XLR cables have a male end and a female end, which are different from one another. For this reason, It is important that you ensure this is a female XLR connection as shown above and not a male XLR as that will not plug into your microphone.
Once you have the correct cable connect the XLR end to the microphone and then with the amplifier turned off connect the 1/4 inch jack to the amplifier input. Then turn the amp on at a low volume and gradually increase to the desired level. You may want to adjust the EQ (bass, mids and trebles) on the amp if you have those settings.
I recommend if you aren’t alone, to get someone else to turn the amp on and adjust the levels so you can stand away from the amplifier with the microphone. If you stand right in front of the amp with the microphone then you are likely to get some pretty nasty feedback and could end up damaging the amp…..or at least giving yourself a headache!
What Kind of Amp Do I Need For a Microphone Then?
This depends on what you need it for. If you are simply using it for band practice and sound quality isn’t a high priority then there is no reason why you can’t use a cheap guitar amp. I would actually say that if you have the option a bass amp may give you slightly better results depending on the singer’s tone and range because it will capture more of the lower frequencies.
Guitar amps aren’t designed to replicate the input exactly and that is mostly what makes them so great for guitar. They add a bit of color or distortion to the sound of a guitar which is what most people want. For a microphone and for vocals you are more likely to want an accurate representation of the input sound.
Specialized speakers used for vocals have two parts, a tweeter and a woofer. Tweeters tend to be much smaller in diameter and therefore can produce higher frequency sounds. A woofer is much larger in diameter than a tweeter and therefore is used for creating the lower frequency sounds. So the combination of these two different sized speakers means you have a big range of frequencies covered, and this is therefore ideal for use with a microphone for.
For playing live: A PA system
For playing live at a gig or concert the best option is to use a PA system. The PA here sounds for ‘public address’ as it is a system that can be used to address a large number of people.
It is called a ‘system’ because it doesn’t just consist of speakers but also an amplifier (not a guitar amp but one designed for vocals usually) and usually some sort of mixer to allow you to adjust levels and EQ.
With any piece of equipment, the specifications vary quite a lot so it is a matter of deciding on your budget and requirements. Some of the specs you are likely to see are:
- Wattage – this basically translates into how loud your system can go. The higher the wattage value the louder it should go before you start to get unwanted distortion.
- Size – A higher wattage usually means bigger size and weight. A bigger size also means the speakers can house a larger woofer speaker and so will be better at producing lower frequencies. Think about how much space you have and how often you may have to move the equipment around before deciding on size.
- Active/ Passive – active speakers each have their own individual power supply whereas passive speakers require power (usually from the amplifier). For speakers of this size ‘active’ is much more common.
You can get a pretty decent PA system suitable for home or small gig use for under $300 which is pretty darn good when you think it includes 2 speakers, speaker stands, an amplifier and microphones!
If you’d rather go for something more portable and cheaper the Powerwerks PA system has everything you need, built into one speaker
For recording: An audio interface
Pretty much everything I’ve mentioned in this article is only really relevant for playing in a live setting. If recording your vocals is all you are concerned about and you don’t need to be heard over loud guitar amps and drums then you can simply plug into your computer or laptop directly using an audio interface.
I wrote an article about what an audio interface is here. But in short, an audio intercase is a way of converting audio signals such as those through a microphone into digital signals which can be stored on your computer as a recording. An audio interface is relatively cheap these days with some great options under $100.
Most audio interfaces will have an XLR input allowing you to simply plug in your microphone directly. Then the audio interface connects to your computer or laptop usually via a USB connection. Then simply record your vocals into your DAW software.