[fsi22]

I recently listened to the Noble Khan, Campfire Solaris, EE Legend X, IER Z1R and noticed this weird phenomenon on chunks missing in the range or of a sense of bottoming out.

It got me curious as these are extremely high end iems and happens to be that they were all hybrid.

I've listened to multiple BA driver iems and they don't seem to have that issue.

My question is, is there a reason that these hybrids are lacking coherence?

 

[castleofargh]

it's really hard get anything conclusive here. we would first need to properly get what subjective impression you're talking about, how much it has to do with frequency response and if at all related, we would then need to try and find a few examples of different designs having almost identical frequency response so we could try to rule that out and find out if the feeling is still there for hybrids(and maybe which type of hybrid configuration).
most likely issues can be found on some multi BA IEMs too, like a huge phase shift or a mistake in the crossover resulting in a small frequency area pretty much missing completely. what could be different is the type or amount of distortions, but that's not something specific to hybrid designs. maybe you can end up with a big dynamic driver stuck in a sealed hybrid design so the amount of distortions and just overall FR for that driver will pay the price of being fully enclosed in a shell, but from my limited experience, I would argue that this is a model specific issue, some manage to give just enough "room", some create small vents, some just use micro drivers, etc.
one last possibility would be related to vast impedance swings, but again this is going to be a case by case situation. you can find some multi BA with crazy impedance over frequency graphs and some hybrid IEMs with fairly stable impedance(for a multidriver IEM). so again that might in some case be the source of some peculiar feeling, even more so if the amp/DAP you're using has a special impedance or just doesn't handle some loads too well. but I don't believe that any of those situations will have "hybrid" written all over it. you should be able to find similar impressions from multi BAs or from good old dynamic IEM. with maybe the exception of having a rather big DD in a sealed shell like I mentioned, that's something designers will tend to avoid so you won't see it happening much outside of maybe a few sealed hybrids.

right now I can't really think of something else. maybe you just got unlucky with the models you tried, and you like/desire something rather specific(the low frequency could be a good place to start the investigation, be it in term of FR or in term of distortions if they rise well above 1% at your listening level).

 

[fsi22]

it's really hard get anything conclusive here. we would first need to properly get what subjective impression you're talking about, how much it has to do with frequency response and if at all related, we would then need to try and find a few examples of different designs having almost identical frequency response so we could try to rule that out and find out if the feeling is still there for hybrids(and maybe which type of hybrid configuration).
most likely issues can be found on some multi BA IEMs too, like a huge phase shift or a mistake in the crossover resulting in a small frequency area pretty much missing completely. what could be different is the type or amount of distortions, but that's not something specific to hybrid designs. maybe you can end up with a big dynamic driver stuck in a sealed hybrid design so the amount of distortions and just overall FR for that driver will pay the price of being fully enclosed in a shell, but from my limited experience, I would argue that this is a model specific issue, some manage to give just enough "room", some create small vents, some just use micro drivers, etc.
one last possibility would be related to vast impedance swings, but again this is going to be a case by case situation. you can find some multi BA with crazy impedance over frequency graphs and some hybrid IEMs with fairly stable impedance(for a multidriver IEM). so again that might in some case be the source of some peculiar feeling, even more so if the amp/DAP you're using has a special impedance or just doesn't handle some loads too well. but I don't believe that any of those situations will have "hybrid" written all over it. you should be able to find similar impressions from multi BAs or from good old dynamic IEM. with maybe the exception of having a rather big DD in a sealed shell like I mentioned, that's something designers will tend to avoid so you won't see it happening much outside of maybe a few sealed hybrids.

right now I can't really think of something else. maybe you just got unlucky with the models you tried, and you like/desire something rather specific(the low frequency could be a good place to start the investigation, be it in term of FR or in term of distortions if they rise well above 1% at your listening level).

Thank you for the detailed reply. It was just specific, what I felt was strange drops in the range. I wasn't looking for any particular signature, rather curious as to what to expect. for example, the Solaris sounded " wonky " in the upper mids, it was a very narrow range, rather than the whole spectrum.

My initial thought after listening to the models I did, was is it more difficult trying to integrate drivers that maybe have different ways of working. Layman's thinking.

 

[bigshot]

There are a whole bunch of variables that can affect response.

 

[fsi22]

There are a whole bunch of variables that can affect response.

Looks crazy complex.

 

[Blackwoof]

To be simple its crossover limitations, I don't get why multi BA and hybrids go above 3 drivers. When the crossover system is pretty bare bones since there only so much space in the shell, Surprised they don't go the Etymotic route have the crossover in the cable?. As for hybrids that the issue with using 2 different driver types, the DD in my view sound like the driver just can keep with the BA's and sound weak. Much rather have a ER4 or any decent multi BA for that reason. Really don't get the 8 - 13.5mm woofer hybrids when that a size I expect better Single DD's to use?.