We should reject hard-to-drive speakers more often

Thinking about this thread for a while and I realize I should have inverted the headline.  What I wish I had written was:

We shouldn't praise speakers specifically because they are hard to drive.  A speaker that is discerning of amplifiers because it is hard to drive is not necessarily any good at playing music.

My bad.

As long as you have the system to match your speakers, you’ll never have to worry about specs and how hard or easy a speaker is to drive.

Well, how exactly do you match those without a lot of trial and error, or social knowledge if you can’t actually rely on specs?

As a consumer this seems like a ton of work. Sometimes this work is a lot more because vendors ( looking at you, KEF ) completely mischaracterize their products.

which compression per se as a mechanically induced phenomenon isn’t relevant.

@phusis I don’t claim to be an expert in all measurements but this seems not to go along with what I’ve seen or measured.

At some point significantly below Xmax I believe there begins to appear evidence of compression, both within the FR and distortion.  I'm not sure how we could attribute any/all of it to thermal without tone burst testing. Take a look at the SoundStage speaker measurements, just about any of them, since they are the only mag I know of that takes compression measurements regularly.

As a mechanical compression artefact this is hardly true for all drivers

@phusis

Then I’d really like to know what you think happens when your reach the maximum excursion of a driver. Either they have limited excursion, and therefore compression, or they have infinite excursion and no compression.

I wish I could find them but I remember seeing tone burst tests showing that thermal compression could happen in a tweeter in less than half a second. You could see the first tone burst perform perfectly, and then half way through the second compression sets in.

The very thin aluminum foil with considerable surface area is essentially self cooling. This test was extreme.

That was kind of where I was going with that. 99% of the surface area of the conductor is directly exposed to air, unlike an actual coil where you may have multiple layers of windings or the former acting as insulators.

Some compression occurs in planar drivers, including ESLs, because the membranes are stretched across a frame. The mechanical impedance is not linear.

True for all drivers, except perhaps the massive fan subwoofers. I think the difference in measurement/thinking about thermal compression vs. mechanical is that thermal compression changes the behavior of the speaker in time, sometimes within milliseconds, while mechanical compression is always there, until you blow the driver. :)

I do think it’s odd audiophiles have fixated on thermal compression, specifically, as being the only one that matters, though I do agree that higher efficiency drivers seem to be at an advantage here.

There’s a reason JBL professional drivers are so expensive, and one of the main reasons that is that they are built specifically to avoid thermal compression even at constant power levels that would make most audiophile systems weep.

Technically Atmasphere is correct, they use the aluminum panel as the voice coil,

That’s just it. They are a panel, not a coil. There’s no "coil" there. They are however electromagnetic instead of electrostatic. In addition, the very large size and direct exposure to ambient temperature makes them behave in an entirely different manner thermally than a tightly wound coil in limited distance between round magnets.

I’m going to go with the Wikipedia article, that specifically calls a voice coil as consisting of a former, collar and winding, as proving these speakers have no voice coil to speak of.  Even if they did, the reasons for thermal compression in actual voice coil speakers can't possibly apply here.

https://en.wikipedia.org/wiki/Voice_coil

Apogees have a voice coil and so thermal compression is possible.

If we are talking about the original Apogee true ribbon 1 Ohm speakers, this would be news to me.

@atmasphere  - I'm trying hard not to use absolutes.  I'm sure your amps do fine!

Rather, I think ESL's bring a lot of other qualities to the listening experience which makes us swant to overlook the hard to drive aspect.

We buy ESL's in spite of the low impedance, not because of it.

yes low impedance in upper registers is nothing to worry about but tuning impedance curve in the lower registers to design a speakers desired characteristic.

My experience with ESL's says that this low impedance (1/3rd of an Ohm) in the upper octave is quite noticeable and often pushes owners to beefier solid state amps.

Let me try to use a better metaphor.

It's fine with me if you buy a car that gets 10 MPG.

What I disagree with is the awe and bragging rights associated with that. No, your car is not better to ride in or more exclusive than high MPG Cars just because it's low MPG.

Also, if you lie about your MPG you should be held accountable.

That's my complaint about hard to drive cars.  I personally have no stake in high vs. low efficiency.  It's the reviewers and machismo that says "Oh, look, my car needs to have 99 Octane fuel to run therefore it's a real sportscar!" that needs to die. 

I guess I missed the point of this statement,

Yes you completely missed the nuance I meant this with, and explained in depth later, and instead applied your own meaning to those words.  Try reading the next three sentences also.  It seems you are conflating my words with those of others who are making other, related points, which I am most certainly not.

Further, I really appreciate the camaraderie you have shown me by immediately suggesting I don’t belong here and should be at ASR, regardless of how you interpreted my statement. That was really elegant and I’ll absolutely attempt to emulate your behavior when I interact with others going forward.

saying a 16 ohm speaker design is better than 4 Ohm speaker design strikes me as hyperbole.

@jeffrey75  Since I've never said or alluded to anything like that statement I don't feel obligated to defend it either.  I encourage you to read all of my posts, in addition to my original on this thread.

I also see this problem kind of hidden in reviews.  Something like this:

Speaker xxx was clearly able to discern the difference between amp A and amp b so it must be very resolving.

It wasn't at all very resolving, or discerning.  It was demanding.

If you buy stuff that doesn’t work well together, guess who’s fault it is ?

If a speaker is rated at 4 ohms but is actually a 2 Ohm speaker that is not the buyer's fault.

My point isn't about whose fault anything is. It's about what  we venerate.  "ooooooh, a half ohm speaker which needs a super amp... I must be mas macho if I get this working!"

No-one’s ’idolising’ speakers that are hard to drive.

I think the real answer is between everyone and no one. The implicit situation set up is "well, it’s a demanding speaker, and it’s my fault for not having an amp up to it."

It’s like an implication there is something wrong with the audiophile if he doesn’t have mega amps. Why don't we instead say "there's something wrong with the designer of this speaker if they rate these 2 ohm speakers at 4 Ohms and expect us to fix their bad design?"

I guess I’m unhappy with speakers being hard to drive... just because they are hard to drive. 😁

And less happy about anyone idolizing that as a feature.

OK, thinking about this this is less about the gear and more about the awe created by hard to drive speakers.  Like we somehow want to make the speakers happy because they are so demanding.  Maybe we should get speakers that are happy with any amplifier instead??

Hey @Bdp24

Well, not saying I don’t l9ike them, ribbon speakers have a reason why they are so low, and they have a pay-off that’s worth it.

Interesting that you bring up the Infinity speakers. Not sure about the IRS, but there were lesser models with crossover designs we’d now consider "naive" at best. You can buy crossover upgrades which maintain the tonal balance while raising up the minimum impedance.

I analyzed a pair of Focal 918 speakers and really had a tough time believing the crossover design was NOT deliberately meant to make it hard to drive. Some caps and resistors in the woofer section dropped the impedance to unnecessarily low values below 100 Hz which could easily have been avoided.

In the case of the Infinity speakers I’m thinking of, they were designed in an era when we lacked the simulation tools we have now, it could have been they got to the right sound and then didn’t want to also optimize to avoid the low impedance.