Is headroom a myth or a technical reality?

[mambo4]

One of the common responses to "how many watts do I need?" Is to consider how much "headroom" you want.
EG, " You may never need to crank your 1000watt QSC PLX amp to 10, but you will appreciate the headroom even at lower volumes"
I must confess unsure what "headroom" actually means. I checked the FAQ and found no Headroom specific entry. Frankly, I'm skeptical.

all other things being the same, is there a measureable effect on tone from using 500 watts a 10 vs 1000 watts at 5?
discounting tube saturation -I know that has an effect - is there evidence that's more than a placebo effect?
Has any audio engineering research been done on this idea?

[billfitzmaurice]

Headroom is real, and applies to clean output. But in the musical instrument genre you may not want too much headroom. If you're a guitar'd player you definitely don't. So the answer to the question is: It all depends.

[lookiel]

Try this:
http://en.wikipedia.org/wiki/Headroo..._processing%29

[hasbeen]

In general, I'll take as many watts as I can get. .....it doesn't matter if I intend to play "loud" or not.

[MRDOOM]

Headroom is the extra volume your rig can clearly and safely produce above your normal volume levels. I've always thought of it as insurance. You may never need to use it, but there may be a time that you really, really need it. In my experience, an amp with the volume maxed will never sound as nice as an amp set at less extreme settings(but that's just me).

[kb9wyz]

It's a myth. I have yet to find a singe amplifier with enough room for me to fit my head into it.

(I just had to.)

[RickenBoogie]

Having adequet headroom means your amp doesn't have to work so hard to get you loud enough, however loud that may be. Pushing an amp to it's limits will shorten it's life.

[Calaverasgrande]

Headroom is more important to fullrange audio such as sound reinforcement and recording. The difference between a good drum sound when you see a band in a large venue is often whether there is headroom available for the drums, not whether the drums are loud enough.

More specifically, drums have a very high peak level compared to their average level. To keep that peak detail intact its a good rule to maintain a 10db margin above whatever your meters are reading. The drums may only utilize 400watts RMS of your amplifier, but their peaks are easily going into the full 1500watt capacity of the amp.

Bass guitar might have some peak level transients which exploit this kind of headroom, but I know I certainly dont like my bass to sound like that. I would rather a smoother sound with less percussive peaks. Though for bassists that do like a percussive tone, peak detail is imortant. they might like to maintain a good 2 to 1 or 3 to 1 ratio watts available vs what the amp is set up to "use". this also gets into gain staging your amplifier and preamp so that your loudest playing might reach exactly 0db on teh output of your preamp, then dialing back the input gain on your kilowatt amplifier to -14db or so.

[greenboy]

Originally Posted by RickenBoogie

Having adequet headroom means your amp doesn't have to work so hard to get you loud enough, however loud that may be. Pushing an amp to it's limits will shorten it's life.

Maybe true with tube amps but with SS it's some pretty whimpy design if this is much of a practical factor. There are plenty of pro power amps that have probably been out there over a decade (or decades) doing full duty loads with little or no service. A lot of them get pulled out of duty before ever seeing a bench, being superceded by lighter, more powerful designs.

[Bassmec]

Improved Headroom is not always an increase watts.
+3db can be got from either doubling your watts or just doubling your speakers with the same watts.
In fact doubling your speakers often gets more spare headroom
than doubling your watts because transistor amps deliver more watts at lower impedances, so unless you are already at your amps lowest safe load impedance thats the way to go.
Ignore this if its a tube amp, they put out the same at all impedances they have a transformer tapping for.

[mambo4]

Originally Posted by Bassmec

Improved Headroom is not always an increase watts.
+3db can be got from either doubling your watts or just doubling your speakers with the same watts.
In fact doubling your speakers often gets more spare headroom
than doubling your watts because transistor amps deliver more watts at lower impedances, so unless you are already at your amps lowest safe load impedance thats the way to go.
Ignore this if its a tube amp, they put out the same at all impedances they have a transformer tapping for.

thanks!
a very useful answer for my situation.

[greenboy]

Anyway, it's scientific enough. Where do you think the term came from? Certainly not from bassists - the vast majority of whom just think it's cool to use the word because it has two syllables and gives the impression a "techie" is nearby ; }

[bass_lord_mutha]

Would you belly up to the table at Thanksgiving looking to stuff your face wearing jeans (which have no give) or sweats (all the give in the world)?

That is my headroom analogy. Carry on.

[Bassdirty]

Originally Posted by MRDOOM

I've always thought of it as insurance. You may never need to use it, but there may be a time that you really, really need it.

Thats how I see it..



It's kinda like ....a motorcycle or car that has lots of power or goes really fast..you dont have to use it all, but its there, just in case..

or like having money bags full of $100 bills..you dont have to use it all..but its there.. just in case...

Or like having a big "@!(k".. you dont have to use it all..but its there.. just in case...

(Sorry)


I like my extra headroom.

[JimmyM]

i agree that headroom is very important, and that's why i never hit the stage with less than 25 watts.

[mambo4]

Jimmy-
sounds like you don't think headroom is all that?
I ask cuz I'll need to make money vs watts choice at some point .
and I wonder if I should even care about headroom.

Choosing between amp A and Amp B, both of which are easily loud enough, is there any reason to favor the higher wattage amp?

[Cycho]

Originally Posted by JimmyM

i agree that headroom is very important, and that's why i never hit the stage with less than 25 watts.

It always pays to be conservative!

The load on the amp varies a lot from moment to moment. There are bound to be transients which require gobs of power for short intervals. This doesn't translate into high volumes, but if there isn't enough headroom you are bound to get some kind of distortion.

[GrowlerBox]

Originally Posted by mambo4

Jimmy-
sounds like you don't think headroom is all that?
I ask cuz I'll need to make money vs watts choice at some point .
and I wonder if I should even care about headroom.

Choosing between amp A and Amp B, both of which are easily loud enough, is there any reason to favor the higher wattage amp?

Only if it sounds better.

[greenboy]

Only if the speakers can actually take it, and the input is gain-structured well to optimize it.

A lot of speakers take maybe 1/2 their rated power before you're living in Fartsville (see thanksgiving dinner example). So having more amp simply means more amp is being wasted.

[mambo4]

From most responses, it seems like headroom is simply the ability to get " louder than usual", in case of transient peaks.
transient peaks have never been an issue for me,
Usually playing into FOH and just need stage volume
I suspect I've never come close to cranking an amp to where It might matter.

...I guess just I don't see how more watts is better -or could even sound better - if volume is taken out of the equation.