Is there a scientific way that intentionally creating "hard to drive" headphones could lead to better sound?

[Sythrix]

So, every major headphone release I see nowadays stresses that their new model is "easy to drive", but still sounds good. OK, fair move, no complaints here with that. That's what most people want. However...

Amir recently posted that he was looking for hard to drive headphones, so that he could safely test a healthier amount of an amp's range without deafening himself. I have the Massdrop THX 789 and am so far enjoying it, but I think about whether or not there's a way to actually take advantage of the headroom it's afforded me.

Is there a way to design headphone drivers so that extra power was required in order for them to function, but ensure that the power is actually being put to use for more accurate and precise reproduction? Can anyone who knows more about the engineering of headphones tell me if this is a possibility? So many amps seem to be multi-gallon jugs, destined to fill a Dixie cup. Shouldn't there be a way to make that power count for more? Or does that just defy the physics of how headphones are designed? Does higher sensitivity and efficiency with power naturally lead to better (read: accurate) sound?

As a real world example, is there anything objectively better about the HE-6(SE) over an easier to drive headphone? Or is it all subjective impressions on what is essentially preference?

I know this topic could easily blend with some subjectivity, so I'll just say I remain open to any comment, but am looking for someone who knows a bit more behind the science . (Please note, I don't need a rundown on ohms =/= to sound quality. I got that, thanks.)

 

[solderdude]

'Tecnical advantage 1' is the weight of the voicecoil which could be lower in high impedance designs simply because the wires are thinner and with a equal amount of windings the total weight is thus lower.
Don't know if one can make high resistance pure aluminium wiring though and if this is used in HP voicecoils.
Less weight ... well you know the drill.
The question is what weighs more.. the voicecoil or the former/membrane and how much can be gained ?
It is a technical advantage but not necessarily an audible one.

Solution... build very low power low impedance headphones with thin wires that can be driven to max. power levels by a phone at 1V.
These also poses very thin wires and thus are lightweight but can't play as loud as the 300 Ohm brethern.

Reason 2 could be to utilise the lower distortion/noise of amplifiers.

The higher the voltage is (no... not above clipping level) the lower the distortion is in the amp and the bigger the S/N ratio is.
It is a technical advantage but not necessarily an audible one.

The real reason for the existence of high impedance is because of the old days.
Tube era (when there were no semiconductors yet) and in studios many headphones were simply paralleled to power amps.
Would be difficult to do with a lot of 8 Ohm headphones.

For home usage there were no dedicated headphone amps.
Instead the output of a power amp was used... high voltages were available which requires 'voltage inefficient' headphones.
There were even 2kOhm headphones in those days.
Add to that most HP outputs had an output resistor of around 220 Ohm (sometimes even 470 Ohm) in series and a high impedance headphone works 'better' in that case.
So... high impedance is something of the past. It hang on because of demand or beliefs or because of one of the above reasons.

 

[Sythrix]

Interesting rundown! Thanks for sharing what you know.

It seems there are some aspects to creating higher demand headphones that would use more power, but they don't really result in better sound. Less weight doesn't appear to directly translate to providing better sound, as you were saying.

The HE-6 is a Planar driver, so I have to wonder if those drivers, or another technology could utilize the additional power in a way that dynamic drivers couldn't. I know electrostats use far more than conventional designs, but that's a completely different interface.

I've read before that headphones are actually the most important part of your sound chain, with their distortion usually being the highest and lending the greatest change to the sound. So while taking advantage of the lower distortion levels inside an amp seems like a good thing, it's not exactly what I would desire in my hypothetical scenario, because it's not the headphones themselves that are improving from having additional power.

 

[bravomail]

then these orthogonal Audeze LCDs...

 

[andreasmaaan]

Amplifiers may tend to distort more into lower impedance loads, so this is one reason why higher impedance headphones might produce superior performance in an amp that can generate sufficient voltage. But the differences are likely not to matter much well below the the kinds of load impedances that are considered “difficult to drive”. IMHO only

 

[maverickronin]

The HE-6 is a Planar driver, so I have to wonder if those drivers, or another technology could utilize the additional power in a way that dynamic drivers couldn't.

The HE-6 has gold traces instead of the usual copper or aluminum. More mass requires more power to get it moving, but since it's coupled to your head it increases vibration and sense of bass impact.

Planars need a lot of magnets too. Using fewer or lower grade magnets can be a tradeoff on price for efficiency.

Also, smaller or thinner magnets can reduce the acoustic impedance of the magnet array and influence diffusion/reflection/refraction and possibly improve fidelity at the expense of efficiency.

Many manufacturers know that plenty of "audiophiles" love tube amps and this influences some to make their higher end models at higher impedances. 30 ohms vs 300 is the difference between an OTL head amp sounding "warm" and "lush" and puking up it's guts.

 

[RayDunzl]

Don't know if one can make high resistance aluminium wiring though and if this is used in HP voicecoils.

Aluminum voicecoils are not uncommon.

https://www.google.com/search?q=sennheiser+aluminum+voicecoil

 

[solderdude]

Indeed, copper-clad aluminium voicecoils are used by quite a few brands.
Haven't seen any pure aluminium headphone voicecoils myself over the years but they do exist.