As you advance through your guitar journey, you’ll likely start to hear about more new gear, so you’re likely to find yourself curious as to what that gear does, and what it’s for. Pedals are often a source of confusion, after all, there are hundreds, if not thousands of variations on FX units, many of which look the same, and even have similar names.
Take for example, volume pedals and expression pedals. Both tend to look the same, but are the terms mutually exclusive? In short, no.
The main difference between a volume pedal and an expression pedal is that a volume pedal only controls volume, whereas an expression pedal can control any number of different parameters given the use case. In fact, a volume pedal is always a type of expression pedal, but an expression pedal is not always a volume pedal.
In this KillerGuitarRigs Guide, we’ll be looking into volume pedals and other types of expression pedals to see what they do, and how you can go about using them in your rig.
- What is a Volume Pedal?
- Where Should Volume Pedals Go in the Signal Chain?
- What is an Expression Pedal?
- What Can an Expression Pedal Plug Into?
- How do Expression Pedals Work?
- Where Should Expression Pedals Go in the Signal Chain?
- Is an Expression Pedal the Same as a Sustain Pedal?
- What to Look for in an Expression Pedal
- Final thoughts on differences between Volume Pedals and Expression Pedals
What is a Volume Pedal?
A volume pedal, as mentioned above, is a type of expression pedal. It is a floor-based, hinged pedal that can be used either as a master volume control or a tool to assist in creating beautiful swelling and sweeping tones.
Volume pedals can either be active or passive. Passive volume pedals are the simpler of the two devices – they act in much the same way as the volume knob on your guitar, and do very little else. They don’t even require a power source.
Active volume pedals, on the other hand, preserve the signal strength coming from your guitar on its way to the amp by way of a buffer. Without this, your signal can suffer from something called “tone suck”, a phenomenon where the top end (treble), is cut out, leaving you with an incredibly muddy sound.
Where Should Volume Pedals Go in the Signal Chain?
Volume pedals can go at the beginning, middle, or end of a signal chain quite happily, but will behave differently depending on where you put them.
Putting a volume pedal at the beginning of the chain, ahead of any overdrive or distortion will result in the pedal behaving like the volume control on your guitar. Fully open, it will give you the full effect of the distortion experienced from the pedals and/or amp. If you reduce the volume on the pedal at this stage, however, you’ll clean up the tone, resulting in less overdrive.
In the middle of the chain, as in after the high gain FX, but before any modulation units, a volume pedal will act in a way that allows you to control the volume, without impacting the overdrive or distortion, and will still allow the modulation effects to keep on ringing out after you stop playing.
At the end of the chain, a volume pedal will behave in the same way as a master volume control. You’ll still have all of your high gain distortion and time/modulation, but cutting the volume will instantly kill any reverb trails.
What is an Expression Pedal?
An expression pedal is any guitar pedal that is placed on the floor and is manipulated by rocking it back and forth with a foot, resulting in a sweeping application or removal of a given parameter.
What Can an Expression Pedal Plug Into?
Expression pedals can be connected to modulation pedals, delay pedals, overdrive pedals, distortion pedals, and even to some digital multi FX units. But, there’s a caveat. An FX pedal that you hope to connect your expression pedal to needs to be “expression ready”. This means it has a separate plug to connect to the expression unit. It’s worth noting that this connection is not always a standard guitar cable, it’s often something called a TRS Stereo plug.
Pedals that are expression ready usually have a socket with “EXP” or “EXPRESSION” labeled on them.
How do Expression Pedals Work?
Expression pedals work quite simply by adjusting the voltage of the signal coming from the guitar on its way to the amplifier. Because they’re floor mounted and manipulated with a foot, they can be continuously operated while a guitarist is playing, resulting in unique tones that would otherwise not be possible while playing live.
Where Should Expression Pedals Go in the Signal Chain?
Some stand alone types of expression pedals, like wah pedals, for example, do best at the beginning of the signal chain. They are almost always active pedals, so they won’t kill the signal strength, but they will benefit from having the cleanest possible input.
If you’re using a generic expression pedal linked to another effects pedal, it doesn’t really matter where that pedal is in the chain, because the expression pedal itself is not technically in-line. The majority of add on expression pedals are passive, this is because they aren’t line in, and don’t need a buffer, and therefore don’t require external power.
Is an Expression Pedal the Same as a Sustain Pedal?
Sustain pedals for guitar are not in the expression pedal category. On a synth, perhaps, but guitar sustain FX units are either on or off – they can’t be rocked back and forth like an expression pedal can.
Having said that, if your sustain pedal does have dedicated input for an expression pedal, then you can control the sustain using the expression unit.
What to Look for in an Expression Pedal
If you’re shopping for an expression pedal there are a few key areas to look out for:
If you’re using an expression pedal on stage and you’ll be traveling with it a lot, consider looking for one with metal housing. This will likely cost more, but seeing as it will be getting stood on a lot, it will be much more durable. Plastic expression pedals can sound just as good, and are often much cheaper, but are far less durable.
Think about the space you have available on your pedal board when making your choice. If you plan to put it to the side, then large pedals won’t be prohibitive, but if you have limited room, then consider a compact expression pedal.
Some expression pedals have a stomp box switch underneath the toe end of the rocker that can be used to switch between modes. A common combination is a wah/volume pedal, although others are available. This can be a useful feature, but it can also be problematic if you accidentally switch from wah to volume during a performance.
Tension and Spring Back
Some expression pedals have adjustable rocker tension, which is great if you’ll be using it a lot. Being able to reduce the weight required to move the pedal will result in less fatigue. On the other hand, if you have a heavier foot and want finer control, you’ll be able to increase the tension to make it harder to accidentally knock the pedal out of the desired position.
There are also pedals with spring back functionality. On these pedals, the rocker will be pushed back up by a spring when you remove your foot. They can be handy if you have mobility issues, but they eliminate the possibility of setting the expression pedal in any position other than off, making them useless as volume pedals.
Digital Unit Compatibility
If you’re using something like a Kemper or Quad Cortex, you’ll find that not all expression pedals are compatible. Check to make sure that the pedal you’re looking at will work with the rest of your rig prior to purchase. The instructions or user manual for your FX unit should feature a list of compatible pedals.
Reversible polarity is another desirable feature in an expression pedal. Effectively, this allows you to reverse the sound output of the rocker, which can have a surprisingly big impact on the resulting sound.
Some expression pedals come with a feature called optical activation. This involves having a sensor on the foot pad of the pedal that can recognize whether or not your foot is actually on it. When there is no foot on the pedal, it automatically switches to bypass mode. Other pedals rely on a physical toe switch to activate the effect.
Final thoughts on differences between Volume Pedals and Expression Pedals
When it comes to pedals there are often a lot of interchangeable terms that various manufacturers will use differently, so it’s understandable that you could be confused as to the exact definition of an expression pedal.
An easy way to think about expression pedals is their ability to assist in expressive playing. Just as bends and vibratos are played with physical manipulation of the strings outside of a linear parameter, expression pedals take the linear signals of an effect and manipulate them with manual input from the guitarist, in turn making them more expressive.