Probably because it won’t work or sound good. Or because it’s not needed.

IEMs on the other hand often do have different drivers for different frequencies, like my xenns top 1 dd for bass and 8 BAs for mid, highs and what not

It's just not really needed. With loudspeakers you're working in a different environment and having multiple drivers can be more beneficial. For headphones, the drivers are often small enough and light enough to reproduce all audible frequencies without issue, and they also work in a different type of environment and produce sound pressure differently than loudspeakers in an open air environment. XM4 probably isn't the best example of a headphone for comparison as they're just not tuned all that well

But why is it so prominent in IEMs? It's not like single driver IEMs are bad, far from it, but there's a lot more products out there that use multiple drivers. Is it a lack of innovation in that area, or are there inherent problems with the placement of the drivers in headphones that isn't an issue in IEMs?

I can only really think of imaging being an issue, but there's plenty of headphones with kinda shoddy imaging.

"moar drivers = moar better" marketing sizzle?

while I'm sure you could make some reasonable case for a 2-way setup to separate high and low frequencies, a lot of the IEM market seems rather over the top, given what you can clearly do with 1DD.

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First of all there are many configurations for multi-driver speakers and coaxial is just one of them and it's not necessarily the best. It's a complex topic, so let's unwrap it.

Speakers need many drivers because they move a lot of air. Unfortunately there is no way one driver can do that and at the same time reproduce highs accurately. A big cone is too heavy to follow a coil that changes direction that fast, so instead it vibrates chaotically. But it gets worse... Basically the speaker plays into open space and every driver has it's spatial character. I don't mean how you perceive it, but actual spatial character - where the driver sends the sound and where it doesn't. We call it directivity. Multi-driver speakers have severe problems with it - they simply make no sense and the response doesn't add up apart from one spot in front of them. Coaxials exist solely because of that. They're supposed to cover the fact that they're separate drivers. Take any other criteria and coaxials suck. I don't mean a particular model, but they are in general a challenge to engineer, because every single part of the woofer messes up the tweeter's response and vice versa. They have severe amplitude intermodulation that comes from the fact that tweeters waveguide (woofer's cone) is constantly moving. Few coaxials sound good outside of car audio. Most of them are weird. In hifi Kef got it right and that's about it. Generally the only way to make a coaxial work is 3-way and up. Two way coaxials are intended to work with subwoofers. So you have a complicated solution that comes with many compromises.

Headphones don't have that problem. There are coxial headphones. I don't remember which, but I don't think they are anything special (?). But let's start from the beginning...

First of all heapdhones are doing fine with one driver. Think about it this way: a speaker is a pump, a headphone is a compressor. A compressor makes high pressure with very little fluid. Headphone driver is big enough to make bass and small enough for highs because it can make that bass with very little displacement. It works by creating pressure, not flow.

There are headphones with many drivers but they're expensive and heavy and comfort is important. Any benefit in sound? I don't see much.

If you want to experience multi-way headphone then there are a couple worth mentioning: AKG K340 and1more tripple driver OE, maybe Meze Empyrean. There were some other, but completely unremarkable headphones from Technics and Universum for example. There is no polite way of putting it - they suck hard.

Axel Grell, who is a famous acoustics engineer, is currently working on a two-way headphone, so hopes are high for it, but nobody expects them to be on par with his single driver work like HD800, and HD800 has a ring driver, that has space for a tweeter inside. Despite that they desided to leave it open.

Have you not heard of people hooking up their headphones and having an external subwoofer hooked up as well? It sounds like the people who do that enjoy it. I'm sure it will be jarring, but I don't want to be overly dismissive of something that could genuinely work if properly developed.

And idk, is that idea really any more jarring than Sennheiser imaging being 3 distinct and seperate fields? They're just different flavors of "bad imaging" aren't they? But if it's possible to have a woofer handle the bass, we can get away with some pretty hefty subbass boosts and extension (with impact) without compromising the tuning of the mids and treble.

Do you have the names of the products that tried this before? I can only think of the nuraphone, but I'd love to see what has been tried before.

Bah, I don't care for the half a dozen BA with like 3 DD setups. But the truthear zero does something genuinely interesting with the woofer that I don't think would be completely unreasonable in a headphone. If anything, the benefits of deeper and more impactful bass make more sense with the increased real estate a headphone can rumble your ears with.

Interesting, just was something I noticed that multi driver loudspeakers sounded better than my headphones ive got while being way cheaper. Kinda makes sense, like I could understand being able to hear the music coming from another driver. Thank you for your reply.

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So why do IEMs do it when wouldnt headphones stand to benefit the most from it, being able to have the lows and mids on the woofer and a tweeter to do all the highs?

While the xm4s I definitely knew they werent going to be audiophile but being beaten out by some budget car speakers should not be a thing. What I was thinking was doing a 2-3 way headphone driver having the frequencies being split to multi drivers made sense to me. As like others have said, a big cone is going to have a hard time doing highs accurately.

I don't know what you mean by sounding better. Headphones are often overpriced because they're a fashoin accessory, so there's that.

The headphones in question are sony whxm4s. And the loudspeakers sound much more clear with better bass, mid, and treble.

Ok, I see. That;s not really a fair comparison then. Wireless headphones don't sound clear in general and the ANC ones are usually tuned for a lot of bass and not much else. So it has nothing to do with driver configuration. $20 Koss heaphones or Truthear earphones will outperform most speakers with their clarity. There's no question about that. The modern tech really sucks when it comes to sound quality.

I think it's a good opportunity to try some wired audiophile headphones or earphones. Stuff like KSC75, SHP9500 or Etymotic earphones. IF you like the sound of your speakers, then these should blow your mind with how much clarity they have for the price.

Oh wow, those look horribly tuned. Though i don't know how you can be so confident about the location of the audio being so incredibly jarring when you haven't ever heard a product that does it remotely well... Because it doesn't exist.

The surround sound thing I don't see ever being a good idea until we move beyond stereo, which I don't see happening for a long time.

I guess we will just wait and see if anyone competent dares to experiment with it. I bet if someone pitched the idea of planar magnetics 70 years ago they'd have gotten much the same response. I'm sure you had people saying it must sound awful and be way too difficult to tune then too!

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Probably space and positions of the speakers. In an IEM the sound goes right inside your ears. Speakers stand in your room far enough away to not make the sound come from different angles. Having the drivers close to your ear in different positions may make the sound come from different angles and thus making positional audio worse.

Other than that it’s probably just not as practical.

You can also take a look into the 1 more Tripple

On headphones the position of a 2nd driver may be too variable from person to person. For example if it aligned to your ears, you get more treble. For a loud speaker there is also this directional aspect, but most of the time the listener will be far and it won't matter that much at that point.

Iem's can do multiple drivers because they are already positioned in a specific spot in the ears.

Are there IEMs with multiple dynamic drivers though? I don't think I know any.

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Yes, antlion duo.

>antlion duo

So a gaming headset. Reminds me of the 5.1 gaming craze we had a while ago with multi-driver, multi-channel headphones.

Ohhhh... You're one of those redditors. You just want to argue and get the last word in. You're not actually interested in discussion.

Sorry man, I'm not interested. You won your argument, congratulations!

Ill definitely try those KCS75s and a SHP9500 after I get paid. After all I did just buy around 80$ in car speaker equipment. Thanks for the info though

I see, thanks

The truthear zero is a huge one.