Dynamic headroom
 

Dynamic headroom. Interesting topic.

Let's hear your thoughts on the subject. :thumbsup:

What is it? What is required? Why does one amp have more than another?




My thoughts on the dynamic headroom of an amplifier:

Let's define dynamic headroom first:

Headroom is simply a term used to denote and describe how much power your amp can provide before the sound starts to break up and distort.


By the way, we should be clear we are talking about audio amplifiers, not guitar amplifiers as the two are very different in headroom and headroom preference depending on the genre and musician.

Intentional distortion in a guitar amp is actually a desirable characteristic with certain music genres but it is a no-no for our applications of having a clean music reproduction of sound.

Seems to me it is pretty straight forward, the amp has specs baked into it. If they are honest, they will present the maximum wattage the amp will be able to deliver at specific harmonic distortion levels before clipping or thermally shutting down? Typically amps will be tested at 1/3 rated power for some continuous amount of time on the bench for thermal stability and then for maximum specs.

Obviously the more clean wattage an amp can deliver, the more headroom it is said to have.

So what do we expect from dynamic headroom outside the amp itself?


Do we think other gadgets external to an amp will help? :scratch2:


In my mind, there are things that just do not jive...


In an amp, we have big ole capacitors in the signal path. Why are they there? If we can get all the instant current/juice from the wall, why bother with big, expensive caps in amps? :scratch2:

So let's see here...

Do capacitors charge instantly?

This charging (storage) and discharging (release) of a capacitors energy is never instant but takes a certain amount of time to occur with the time taken for the capacitor to charge or discharge to within a certain percentage of its maximum supply value being known as its Time Constant ( τ ).


Seems pretty clear to me but I could be missing something here.... That the answer has always been the big ole' capacitors for that punchy, iron fisted grip on the speaker that matters the most. You can't "push" current through the amp fast enough for transient dynamics, so therefore, they have to "reside inside the amp to begin with". :smoking:

I've never heard an amp that I knew had tons of "capacitive storage" inside it, not to sound in total control over the speaker with plenty of dynamic headroom and bass control. Whether it was plugged into the wall or not...

I have however heard plenty of weakness from amps that did not have plenty of capacitive storage and a beefy power supply.


How about your experience?



So as far as I am concerned, I got your dynamic headroom right here pal... :D




https://i.servimg.com/u/f23/16/43/72/52/c360_242.jpg

https://www.reelaudio.co.uk/images/p...KrellComp1.jpg

Good video on "headroom" from Paul McGowan. He is talking about the "sweet spot" or the linear operational zone of transistors which is a very important concept if one is wrap their head around this "headroom" topic.

https://youtu.be/th8CxTk22pY

How much is a pound of your dynamic headroom? :D

570 pounds worth of an amplifier...


https://s2.desu-usergeneratedcontent...3820753688.jpg

Re the definition, I always thought headroom was the ability of an amplifier to exceed its continuous power rating for short bursts to accommodate short musical peaks.

I’ve tried with McGowan - it’s probably just me, but I can’t tolerate more than about 30 seconds of his pontification.

I think that's the commonly accepted definition. The same applies to other things, such as analog tape, where dynamic headroom is the extent to which you can briefly exceed nominal "0 VU."

There is a limit to everything. One can keep pushing the transistors with brief bursts until one approximates the point at which they fail. Typically that is way outside the linear operating zone of the transistor or the sweet spot and would sound like crap anyways. Would not be honest but good for spec numbers.

Or one can conservatively say 180w vs the actual 200w that the amp can safely operate for example and call "that" extra headroom? That is not exactly good marketing either.

Further, the "dynamic headroom" breaks down into the chain of events that unfolds with various rooms/speakers. Same amp in two different systems would mean very different operating zones.

One guy listening at less than 1/3 rated power vs another who is bouncing off the dynamic ceiling with his large room, big, inefficient speakers and very loud SPL levels.

The more important question is, would an external device of any sort improve the actual specs of an amplifier? :D

Do the 200 mph ratings of expensive sport rubber tires make the car traveling at 55 mph faster? Would the car have more dynamic headroom at that speed because of those tires or because of its own reserves/dynamic headroom?

How about at 150 mph as the car bounces off the rev limiter and reaches the end of gearing and engine rpms? Does the rubber help it reach 200 mph? :D


Should one expect the amp to have a different bench measured result of performance plugged into the wall vs a power conditioner of choice? How does that work?

It's not quite that. It is an "envelope" into which a recording engineer should fit the recorded signal. One does not want to exceed it and go into a clipping zone as that is distorted signal. https://youtu.be/7ZAYSeGgy-I

Paul's videos are quite useful most of the time for general knowledge. I can always tell how uncomfortable he is with the typical "can of worms" topics such as fuses, cables, etc but he is in the audio guild and can't throw others under the bus... He starts out by saying oh boy, you've opened a can of worms and then quickly readjusts as he realizes where that is going to go. :D I understand the position he is in.

Paul had me cracking up with his analogies in this video. Data is data, shoes are shoes, underpants are underpants.... Gotta have a sense of humor in this hobby... :laughin:


https://youtu.be/ld68LCIRqQg