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Discussion in 'Amps and Cabs [BG]' started by Chris 'Wighat' Jordan, Mar 19, 2017.
Been seeing the term "head room" applied to speakers some lately. Doesn't jive with me.
Amps that power the cabs, i believe, is what does or doesn't have the headroom. IE: Having more wattage than you need
The engineering definition of headroom doesn't jive with my own notion but I think it could be applied to speakers.
Strictly, headroom is unused system loudness if I understand @agedhorse correctly.
So a speaker not pushed to past what it can do without frying, dying or distorting has headroom, I guess.
My own idea of headroom is the range of dynamic loudness you can add over your ''quiet'' dynamic. That is loudness that might well get used so doesn't qualify in the engineering sense of headroom.
Why are you prejudiced against speakers, Chris? All the glory goes to the amp but can't give the speakers a little love?
I totally call it headroom when it comes to speakers. Don't care if it's correct, either.
And similarly, you can have more speaker power handling than you need.
My amp puts out 180 watts clean. My speaker cab can handle 800 watts. My cab arguably has more power handling than I need. Thus I have speaker headroom, as even if I crank my amp fully, I'm unlikely to reach the limits of my cab's handling.
I think you and Jimmy are comin' correct
I never even thought of it that way around, but it all makes sense now!
All my speaker headroom gets donated to charity - NO EXCEPTIONS.
If you have an amp rated at 500 WRMS and a cab rated at 500WRMS, but you only use half that, you have 250WRMS of headroom for both amp and cab.
Exactly. Andy recommends more speaker headroom than amp. That makes it more goof proof and less likely to damage the cab when cranked; less likely to hit the limits if that particular cab doesn't tend to fart out to where you can hear it or if the cabs the thermal (wattage) limits exceed the mechanical limits.
I tend to walk on the other side of the street and like plenty of amp. Not because of the misconception that too low of wattage blows speakers. It's a performance vs. reliability trade off. Andy is more about reliability, I'm more about performance. Ironically, it doesn't matter in my case, because *I* don't perform well
Having more volume than you actually need is headroom....
Having a 1000watt head when you only need 500watts is headroom.
Having a cab that can handle 2000watts for that 1000watt head is also headroom.
I always aim for more watts in the cab than I can push through the amp.
I want my speakers to sound like they're enjoying the gig as well.
Speakers can be operated clean, or they can be driven into a good sounding distortion. They can be further driven to bottom out and fart. I think of speaker headroom as the margine below farting and at the the onset of speaker distortion. Transient spikes are accommodated and still sound good.
The two boundries of the speaker headroom margin are sliding based on the application. It can be defined in different ways. Some players like a little distortion, others want no speaker distortion, their requirements are different.
In recording, 0 on the VU scale (+4dbU) is the lower boundary of the headroom. Where the electronics start to distort is the upper limit, let's say that is +24dbU, so the headroom is 20dbU. This is a margin that can allow peaks without the audio distorting. It's more complicated because there are different forms of distortion such as compression.
Headroom of an amp is gauged differently. With a pedal preamp for instance, with a 9V DC battery, distortion sets in at a certain level because the power supply drops when a heavier deman is placed on it. If you use an 18V DC supply, you get a more clean volume level before distortion set in. There is a difference in clean volume with the higher voltage power supply, this difference is an increase in the headroom. The power supply is one factor that determines the headroom, the circuit design also plays a role. The same applies to an amp. If the power supply is not performing up to spec, the amp looses clean headroom, distortion sets in earlier. Likewise, the performance of the circuits in the amp affect headroom.
So the term headroom applies equally well to amplifiers, speakers, and speaker cabinets, how it is characterized is different though.
Excursion limits (physical cone travel) and power handling (heat and energy dissipation)
Glad you mention it. Since I am totally inexperienced in that field, I hope you don't mind me asking.
What kind of headroom is between good sounding distortion and below farting; headroom from tonal aspects, or also in terms of reliability?
Just wondering how to notice. Guess, the answer depends on how the distortion is generated; by reaching xmax? Or by pushing the cap's fabric harder?
I have no recording experiance, but wouldn't the recording example you gave be best labeled dynamic range? (I am asking, not claiming it is so).
Certainly most things are usually way more complex than they seem on the surface, or for that matter more complex than most people want or need to know for what they do. And thats not to say your descriptions are going overboad... I like learning.
Some speakers break up more gradually while others hardly complain until pushed over the limit. Some sound good overdriven while others don't. It depends upon the design.
When I initially saw this thread, it made me think about so-called "underpowering", except sort of in reverse. The underpowering meme suggests that there should be no speaker headroom, or in other words that a speaker's power rating should be evenly matched to the output power of the amplifier. Some who promote this meme go on to claim that speakers can be damaged if fed with a less powerful amplifier (which is false - too much power destroys speakers, not too little). Generally speaking, for bass applications, it is a good idea to use speakers which are rated to handle more power than you are going to put into them... "speaker headroom" if you will.
Headroom is the difference between the maximum performance used versus the maximum performance available. Headroom, the concept, exists in all physical systems in some way or another.
Yeah, in my experience it's as much about HOW you're pushing the speaker as it is about HOW HARD. The more low end you're throwing at it, the narrower the range where the speaker is distorting but not farting.
Butting in to answer, I'll say it's unpredictable. IMO the mechanical limits vs. watts and knobs would be the product of the cab design and the driver. I have not seen specs on commercial cabs that indicate anything mechanical, but hopefully that is included in their max. wattage rating.
Also for the note that it might be rather risky.
I am my too shy, anyway, to try something that might hurt my dear cabs. Call me a coward, but I rather not Blow My Speakers, even as a ManOwaRrior
Though, I find the idea interesting that there may be players who really found kind of a safe sweet spot where their cabs contribute distortion, as well. Never thought of using speakers that way.
You're right, I totally forgot about the cabinet design and its impact on the driver's performance.