The author is a guitarist and bassist with over 35 years of experience as a musician.
What Is Headroom?
As it relates to guitar and bass amplifiers, headroom refers to how loud you can turn up an amp before it begins to distort. More precisely, it is the gap between an amp's normal operational volume level and the maximum level it can operate at without distortion. You may also hear this referred to as clean headroom.
We can think of headroom in two ways:
- In an absolute sense, amps that can be cranked up to high volumes without distorting have a lot of available headroom. Typically, powerful, high-wattage amps are considered to have more headroom and lower-wattage amps less.
- In a practical sense, the degree to which headroom plays a part in your sound depends on your playing environment. In this context you can think about headroom in terms of the available power above and beyond what you need for a specific situation.
Need a few metaphors to make this a little more clear? Here you go:
Imagine you are traveling down a highway where the speed limit is 70 mph. It’s one of those insanely busy highways with lots of big rigs and maniac drivers and if you can't keep up with traffic you will be blown off the road.
No problem. You are driving a sports car with a powerful engine and you can go 70 while barely pressing on the gas pedal. The ride is smooth and comfortable, and if you wanted to you could go much faster without causing strain on your vehicle or the passengers. In fact, if you were to find yourself in a bad spot, a quick press of the gas will speed you up and get you out of danger. Your car has plenty of power for that situation, and even power to spare.
Now imagine the same situation, except you’re driving one of those tiny European compact cars. You have to stomp the gas to the floor to hit 70 mph. The car shakes and rattles down the highway, and the engine sounds like it is going to explode. It’s a miserable, jarring ride, but you must push the car to its limit just to maintain your speed. If something bad were to happen you can’t push down on the gas and speed up. You have no more available power.
In that example, obviously the powerful sports car is an amp with a lot of headroom, and the tiny compact car is an amp with much less headroom. Even if the speed limit were 90 our sports car could get the job done, but the little car has no hope of keeping up with that pace.
More power usually means more headroom. However, its is just as important to consider that if the speed limit were 30 mph the little compact car would do just fine. While headroom is valuable, how much it matters to you is highly dependant on your playing situation. And, as we'll see, things get even more interesting when we consider tube amps and overdrive.
Solid-State vs. Tube Amp
Both solid-state and tube amps clip or distort when they are turned up beyond their functional limit. For example, your amp may sound clean and clear with the volume knob on seven. Turn the volume past that and it may begin to distort.
The point where an amp begins to clip is highly related to its available power. The more power, the more you’ll likely need to crank it up before it distorts.
So far it sounds like the more power you have the better, but it’s a little more complicated than that. Some musicians actually prefer amps that need to be cranked up. Many guitarists, and some bassists, love the sound of a tube amp pushed beyond breakup.
Tube amps pushed hard tend to sound sweet and musical, and just about every form of modern music has benefited from the sounds they create. Distortion pedals, dirty channels on solid-state amps and even digital modeling amps strive to replicate that beautiful tube overdrive.
Solid-state amps are a different story. Pushed into distortion they sound harsh and unpleasant. Most musicians and audio engineers do everything in their power to avoid solid-state distortion. That means having enough headroom, and the more power you have to spare typically the better your amp will sound.
Headroom and Bass Amps
The bass is an instrument that demands a loud, clear sound in most forms of music. Bassists don’t want their tone affected by harsh-sounding amps, and they don’t want unexpected distortion to their signal.
Therefore, for bass amps, headroom is a very important thing. You want lots of available power so your signal is always clear. This, along with the inherent difficulties of the human ear to hear lower frequencies, is the reason we see bass amps rated at 1000 watts and more.
Most bassists feel it is better to have a powerful bass amp you only need to turn up a fraction of the way rather than a less-powerful amp you need to crank up.
You probably don’t need a 1000-watt bass amp, but you should consider getting one with as much power as you can afford. For a band situation with a loud guitarist and heavy-handed drummer, I’d shoot for a minimum of 300 watts, but more is better. When competing with monster guitar amps you don’t want to have to push your bass amp to the limit to be heard.
What about tube bass amps? Tube overdrive sounds great for bass, but whether you want that kind of sound out of your amp is a matter of taste. Most bassists don’t use distortion, and they opt for tube amps with a lot of power and a warm, clear tone. Just like guitar players, if they so desire bassists can use a distortion pedal or boost to hit the front end of their amps harder and push them into overdrive. Some bass amps even have an onboard distortion effect.
Headroom and Guitar Amps
Solid-state guitar amps are in somewhat of the same boat as bass amps. You don’t want to push them so hard that the signal is distorted. You need plenty of power for your situation.
Even if you play rock or metal and you think your need nasty, nasty distortion to get the sound you want, a dimed solid-state amp isn’t the way to get it. It is important to realize that the distortion effect available in the "dirty" channel of many guitar amps is not the same as harsh solid-state clipping.
Tube amps do sound good when pushed into overdrive, and many rock guitar players choose moderate-wattage tube amps because they break up at lower volumes. Overdriven tubes sound amazing, and you might not care if you have to turn your amp up to the point where you don’t have a lot of headroom left over. If you play rock or metal this is probably the case, and one of the reasons many players prefer tube amps in the 40-60 watt range rather than 100-watt monsters.
But some guitar players do want a loud, pristine sound, especially in jazz or other genres where a clean signal is desired. They don’t want their amp distorting, and so they choose high-wattage amps that will give them more volume without breaking up.
So, when it comes to tube guitar amps the amount of headroom you need is very much dependant on your genre and situation. If you want to push your amp into overdrive you may choose an amp with less headroom. If you want a clean sound, more is better.
Choosing the Right Amp
Here are the practical takeaways from everything I just wrote:
- If you are a bass player, consider choosing a powerful amp with lots of headroom for your playing situation.
- If you are a guitarist in a genre such as jazz who needs a clean, loud tone consider a powerful tube or solid-state amp with lots of headroom.
- If you prefer solid-state amps in any genre consider a powerful amp with lots of headroom.
- If prefer overdriven tube amps chose a moderate-wattage tube amp with low headroom for your situation.
- If you are choosing a practice amp or a small amp for low-volume rehearsals worry more about relative headroom and choose an amp that has enough power for your situation.
Finally, while it is generally true that powerful amps have more headroom, remember that power rating alone isn’t always an indication of the amp’s performance. For example, as you’ve probably noticed, tube amps tend to sound louder than solid-state amps with the same power rating.
And, there are often differences in two comparable guitar amps with the same power rating. I’ve used 80-watt solid-state amps that were loud as heck, and 80-watt solid-state amps that were pretty wimpy.
It’s a good idea to gather opinions on gear from people who have actually used it in the same way you are intending. Even better, get out there and try it yourself.
Hopefully, this article helped you to better understand headroom and how it relates to your playing.