One of the questions we often get is what the term “headroom” actually means in guitar pedals and why it matters.
Dynamic Range
Every device that works with audio has a certain dynamic range. This range is limited on two sides. At the bottom of the range are signals that are whisper quiet (the noise level), but just audible. At the top of the range are signals that are as loud as possible without distorting the signal.
what is headroom
As soon as a signal gets louder than the highest level that the device can handle, distortion occurs. The signal is then above the headroom of the device. This is the point where the device can no longer accommodate an increase in the signal level. With analog devices, such as most overdrive/distortion/fuzz guitar pedals, the signal level approaches the power supply level of the pedal.
Nominal work level
There is a clear standard for this in the studio world. This standard is also known as the nominal work level. Studio equipment often uses VU meters that are scaled so that 0VU is approximately equal to +4dBu . Professional analog equipment can usually handle up to +24dBu of signal, so about 20dB is left. This 20dB is the unused portion of the dynamic range and is called ‘headroom’. It is the safety margin of analog systems.
Headroom standard
With guitar pedals there is no clear standard like that of the studio world. Dynamic range is often referred to when one talks about headroom. But as a rule you can say that a pedal with a lot of headroom can handle loud signals without overdrive. In addition, a pedal with a lot of headroom often sounds ‘open’ and ‘dynamic’.
Pedals that work on both 9 and 18 volts
With some pedals you can increase the headroom yourself. Many Wampler pedals work on both 9 and 18 volts. At 18 volts, the pedal initially gets more volume than at 9 volts and also more headroom. For example, if your Wampler pedal starts to oversteer too quickly and you want it to be a little more gradual, try increasing the tension. Please note, not every pedal is made to work with both 9 and 18 volts, always consult the manual for this!
Why is headroom important?
If you want to have more control over how the overdrive occurs in a guitar pedal, it can sometimes be useful to increase its headroom. When you connect a guitar with a high output, a pedal can overdrive too fast or too much. Raising it then ensures that you get more control over the effect. In addition, the character of the overdrive will often change (slightly) and the volume of the pedal will increase.