Do guitar speakers change frequency response with volume?

[James Freeman]

For example if you drive the speaker with clean 1W to 50W, does the frequency response changes?

I think with high cone displacement the air volume in a closed cab should have some effect on THINGS.... or?

@jay mitchell can you share your experience?

@FractalAudio do you have some useful links where it has been discussed on the Fractal forum?

 

[woody]

Yes, they do.
They all do it differently and to different degrees, though.

The first noticeable point is when yo slowly turn an amp up from nothing and it's all thin and wimpy, and suddenly it gets loud. That's the point when a speaker membrane really gets excited by the driving signal.
Then at some point, especially with old fender amps, you get cabinet involvement, when all the wimpy boards that are loosely screwed together start to shake, rattle and roll. (PA speaker cabs are so much more rigid and stable in comparison.)
Then some speakers start to saturate and distort, which generates overtones, when some frequency bands get squashed, because the speaker can't push the air harder in a linear manner.
Then there is cone cry, which is the speaker itself resonating an generating noise when pushed close to it's limits of power handling.

Guitar speakers are very nonlinear in their behavior.
It's not an easy "at 50W you get this", but it all depends on the individual speaker, the cab, the impedance coupling with the power amp and the signal you are driving it with.
e.g. a speaker that handles a 50W 1kHz sine wave very well could totally get whacky pummeled with 50W of downtuned dual-rectified powerchords...

 

[Orvillain]

 

[laxu]

Worth a watch. A Jensen speaker designer weights on a lot of this stuff.

TL;DW: He says that until you are driving those speakers to their absolute limit, what changes is the amount of air moved and how you perceive that sound rather than the speaker doing anything particularly different. Premise here being you aren't e.g running the amp into powertube distortion which changes the sound.

You can try this for yourself. Record a DI track, then pipe it through a high wattage poweramp into your favorite cab, record it first at very low volume, then higher volume. Then normalize the volume of the tracks so one is not louder than the other and listen to them with your studio monitors or headphones.

They should sound very similar but the low volume one may have much more noise because you have to compensate with mic preamp gain to get a good recording level.

At low volumes you are subject to a number of factors before any speaker related things come into play:

• Different perception of the frequency spectrum at low vs high volume. This is the absolute biggest factor. I can take my Axe-Fx 3, where no real amp things apply as the simulation can be cranked but at any volume, run it through studio monitors and simply turn the output volume knob on the unit and it will sound very different when just a bit louder.
• Bright caps on gain/volume pots having more effect.
• Amps having volume controls where they literally do nothing until you raise the knob a bit. I was surprised to find CTS pots especially have this sort of "feature" where even up to 1/4 of their travel the resistance does not change from zero. This does result in a beneficial effect where raising the volume from zero to 0.5 does not cause a big jump in volume but instead you find that the amp comes "alive" when it reaches about 9 o'clock on the volume.

 

[Cirrus]

Yeah. They're non-linear as Woody has explained.

It's one of the reasons I think IRs of alnico speakers never sound or feel right to me. It's not hard to hear how an alnico blue compresses and reacts to transients at low vs high volume, and to be fair it's also a thing with ceramic greenbacks. An IR isn't dynamic in that sense.

I think once you get into the realm of putting two or 4 high wattage speakers in a cab, it's practically not going to matter loads. Because even over quite a wide volume range, the difference of putting say 15 or 50 watts of power into a cab that's rated for 200W+ might feel like it should really matter, but 15 watts is enough to get the speaker cones moving nicely and 50 watts isn't even going to make them break a sweat. It's just not gonna be the same demonstrable effect over the practical range of powers you'll use vs when it's a 100w marshall into 100w cab, or 30 watt combo into two 15 watt speakers.

Then there's the amp-speaker interaction. It's not a one way street - the speakers can be more or less dampened by the design of the power section. If all else could be equal, 50 watts into a cab wired in series with no negative feedback in the power section would make the speakers respond differently to 50 watts into that same cab wired in parallel and negative feedback in the power section.

Really, the devil is in the details and the answer's gonna change depending on the rig.

 

[fretworn]

 

[Deadpan]

I have shot IR's at different volumes and the results were the same.

 

[James Freeman]

We have conflicting opinions....

 

[jay mitchell]

Its been discussed ad nauseum already for years. Most of the "knowledge" on the subject that gets spread around is nothing but superstition.

 

[Gearzilla]

Its been discussed ad nauseum already for years. Most of the "knowledge" on the subject that gets spread around is nothing but superstition.

 

[woody]

I have shot IR's at different volumes and the results were the same.

From there, one could come to two different conclusions.

In a totally unrelated matter:

 

[jay mitchell]

From there, one could come to two different conclusions.

Those conclusions being what?

In a totally unrelated matter:

In answer to the question, "How long can you play a Cranked 100W Marshall into a 25W Greenback before it BREAKS?"

I say, "Apparently a hell of a lot longer than I can stand to listen to that crap!"

Also an FYI to the guy in the vid: when you get a guitar speaker hot enough that you can smell it, you've already done permanent damage.

 

[Cirrus]

Should there have been a trigger warning in this thread?

 

[woody]

Those conclusions being what?


In answer to the question, "How long can you play a Cranked 100W Marshall into a 25W Greenback before it BREAKS?"

I say, "Apparently a hell of a lot longer than I can stand to listen to that crap!"

Also an FYI to the guy in the vid: when you get a guitar speaker hot enough that you can smell it, you've already done permanent damage.

Yeah, he probably damaged the speaker.
It's a bog standard greenback though, I've seen people destroy more expensive or rare stuff on youtube.
And at least I find this an informative experiment (which I would not have conducted myself).

Dismissing his playing style to refute the evidence presented in his video is telling, though.
Anyways.
I shared my experience.

Feel invited to crank an amp into a low wattage speaker.
Do record what you do, if possible and be sure to level match before listening back.
Share your experience, if you feel inclined to.

 

[jay mitchell]

Yeah, he probably damaged the speaker.
It's a bog standard greenback though, I've seen people destroy more expensive or rare stuff on youtube.

He specifically stated in the video that he did not want to damage the speaker.

And at least I find this an informative experiment

I do not.

Dismissing his playing style to refute the evidence presented in his video

"Playing style?" I was referring to his playing competency and guitar tone. And there's no "evidence" to refute. He played a 100W amp into a single 12" speaker and gradually increased the volume until - according to him - he could smell the speaker, which was still functioning when he stopped.

I shared my experience.

You shared a video. Given that you explicitly stated that you wouldn't have done this yourself, it obviously wasn't your experience.

Feel invited to crank an amp into a low wattage speaker.
Do record what you do, if possible and be sure to level match before listening back.
Share your experience, if you feel inclined to.

I have the capability -- the equipment, facility, and skills - to perform instrumented, objective, repeatable power handling tests and have done so from time to time for several decades now. Those tests are no fun at all to listen to. In fact, you'd need hearing protection to be in the room even briefly. Which brings up another point: the guy in the video would do well to have his hearing checked. 117dBSPL is loud enough to cause permanent hearing damage within a few minutes.

 

[Cirrus]

Loud speaker go boom

 

[woody]

Loud speaker go boom

Can't be.
IRs never smell.

 

[ejecta]

Can't be.
IRs never smell.

IR dumpster diving stinks though.