Compression is a widely used effect for both guitar and vocals. The function of a compressor is to create consistent dynamics, raising any low-volume signals and limiting those that exceed the threshold.
So, Can you use a guitar compressor for vocals?
Guitar compressor pedals can be used for vocals but are specifically designed for the voltage level and signal strength of guitars, so there is likely to be an impedance mismatch when they are used for vocals. However, this can lead to interesting results.
If you aim to apply clean compression to your vocals, then using a guitar pedal is probably not the right option.
The inputs on a guitar compressor are designed specifically for line-level instruments, while most vocal microphones use a balanced signal. Nevertheless, the compressor will work on vocals, it will just apply some coloration and tonal adjustments that are likely to make them sound lo-fi.
How To Use A Guitar Compressor For Vocals
Although it’s certainly possible to use a guitar compressor for vocals, several factors must be considered. Firstly, we need to discuss the connectivity issues that you’re likely to face. Guitar pedals generally have 6.35mm jack inputs, specifically for line-level instrument cables.
- A line-level signal is generally around 1,000 times greater than a balanced mic-level signal.
This could also be measured as being one volt stronger.
This power difference is significant when discussing the use of guitar pedals for vocal purposes because obviously, it will require you to connect a microphone to the input that is designed solely for line-level instruments.
Although it’s not advised to connect unintended devices and cables to guitar pedals, it is highly unlikely to cause any damage to either the compressor pedal or the microphone. For that reason, you can experiment without the fear of any power surges or inconsistencies wreaking havoc on your gear.
The vast majority of vocal microphones use three conductors to carry a balanced audio signal.
As I previously mentioned, this signal is significantly weaker than the signal carried by line-level instruments like guitars, basses, or synthesizers. Vocal effects pedals are designed to facilitate balanced signals, while guitar pedals are not.
The good news is that there’s no harm in trying to use a guitar compressor for vocals. To do this successfully, you’ll need a particular type of cable. This cable must have a female 3-pin XLR connector on one end, and a 6.35mm jack connector on the other end.
These cables are fairly inexpensive and easy to acquire. They are commonly used to connect the outputs of an audio interface, preamp, or mixer to studio monitors. This connection requires a balanced cable and often needs a 6.35mm jack connector to take the signal out of the interface, preamp, or mixer.
Here are the basic steps you need to follow to use a guitar compressor for vocals:
- Acquire a balanced female XLR/6.35mm jack cable
- Connect the female XLR to your microphone
- Connect the jack to the input on the guitar compressor
- Connect the compressor pedal to a power supply
- Adjust the levels on the pedal until you can hear the effect on the vocals
If you follow these steps, there’s a good chance that the guitar compressor will interact with your vocals. Indeed, it helps if you have a vocal amplifier or speaker that you can send the output from the pedal into, but if you don’t you can use your audio interface input and listen through the headphone port.
This video is great at demonstrating how guitar pedals can be used for vocals.
This is likely to subject your vocals to some compression, but the results at this stage may not be desirable.
This is because of the impedance mismatch that is caused by connecting a balanced device to a line-level device. Consequently, we need to consider the ways to get the best out of this combination.
Guitar Compressors & Vocal Tone
The wonderful thing about music is that it is a completely subjective topic.
What sounds great to one person, may sound overly produced to the next, and likewise some people may love the sounds produced by doing things the “wrong way”, while others may prefer a polished result.
Following the general rulebook is fine if you want to produce predictable results. I would argue, though, that many of the most iconic musicians, producers, and mixing engineers have created their signature sounds by experimenting with methods that would be considered unconventional, and perhaps incorrect, by some.
The fact of the matter is, guitar compressor pedals are not designed for vocals. This is quite clear, due to the power mismatches, connectivity options, and the way the inner circuitry within a guitar pedal has been designed.
Nevertheless, many musical genres have been born out of experimentation, and therefore I’d encourage anyone to test out unorthodox methods.
- Using a guitar compressor for vocals has the potential to create really interesting results.
The term lo-fi describes music that has been intentionally produced to sound less polished, and of a lesser sonic quality than the average music you’d hear on the radio. This style usually results from musicians working with the equipment they have at their disposal, turning their so-called limitations into stylistic qualities.
When you use a guitar compressor pedal for vocals, you are likely to get a lo-fi sound.
It won’t sound high-quality, but the results will be interesting nonetheless. If lo-fi is a style that interests you, then using a guitar compressor for vocals will provide you with many hours of fun experimentation.
If you prefer to stick to the tried and tested methods and want your music to sound clean and polished, then, unfortunately, using a guitar compressor for vocals will likely not produce a desirable result.
There’s no harm in trying, though, and you might be surprised at how good the coloration and tonal alterations caused by this combination sound!
Check out this article on recording vocals in a car! You can read it here.
Compressor Settings For Vocals
The easy part is connecting your vocal microphone to a guitar compressor pedal. This will take very little time, and you’ll likely be able to hear the results instantly. With that being said, you must understand how to adjust the settings on the guitar compressor pedal to make them compatible with vocals.
Due to the input signal strength of a microphone being around 20dB hotter than your average guitar signal, the pedal will interact with vocals very differently than it would with a line-level input. To compensate for this, it’s a good idea to turn down the Sustain control on the compressor to zero.
The Level control will need to be turned up very high.
This function blends the direct input with the compressed sound, and if you’re using it for vocal recordings, you will need to apply the maximum compression to protect the levels.
Then, the Attack should be set to zero initially. This is because the attack controls the time it takes for the compression to kick in.
- When using a guitar compressor for vocals, you want the compression to start instantly to control the dynamics and prevent any overloads from occurring.
Don’t worry if it sounds a little messy initially. You can adjust the Sustain and Attack levels as you listen, adding minimal amounts to each until the compressor meets your desired results.
Alternative Methods For Vocal Compression
Using a guitar compressor for vocals is certainly an option worth exploring.
For those who enjoy unconventional tones, and lo-fi sounds, it is likely to provide you with some brilliant results. However, for the tone purists, they may be left disappointed by the lack of audio quality that this combination results in.
Thankfully, there are two alternatives you could use. If you require vocal compression solely for live performances, then purchasing a pedal that is designed specifically for this purpose would be your best option. You could also use rack-mounted compressors in the same way.
Or, if you require compression mainly for studio vocals, you can simply use DAW’s built-in compressor or a VST plugin. These alternatives are very easy to use and connect to your microphone via the audio interface input.
Here’s a table that shows the benefits of each method for vocal compression.
|Guitar Compressor Pedal||Female XLR/ 6.35mm Jack||Lo-Fi Sound||Unpredictable|
|Vocal Compressor Pedal||Female XLR/Male XLR||Clean compression||Fairly expensive|
|Rackmount Compressor||Multiple Options||High-quality results||Lacks mobility|
|Compressor Plugin||Balanced XLR||Convenient and versatile||No physical device|
Are the controls on a guitar compressor the same as those on a vocal compressor?
Yes, both guitar compressors and vocal compressors usually feature the following controls. There’s the threshold, ratio, sustain attack input gain, and output gain. Each of these controls adjusts the nature of the compression.
What is a good compression ratio for vocals?
When you add compression to vocals initially, it’s advisable to start with a ratio of 4:1. If you accompany this with a medium-fast attack and a medium release, then set the threshold to around 5dB of gain reduction, this is a good starting point for vocals.
Should you EQ or compress vocals first?
Whether you add EQ or compression to your vocals first comes down to personal taste. EQ first will produce a warmer, well-rounded tone, while using a compressor first makes the sound cleaner and more polished.