[Designdude]

Hi guys,
 
So, I have heard that hard acrylic IEMs produce superior sound over the silicone ones due to the cavity in the shell. Can anyone shed some light on this at all? I've heard some theories along the lines of the cavity allowing drivers to move more freely but I assumed that with balanced armature drivers the change in airflow wouldn't really change as they have metal casing.
 
I'm new to all this so I would really appreciate any input from people that have a better understanding of the tech.
 
Thanks. =)

 

[Mython]

Some BAs have vented casings, which may be a major factor in differences in sound between acrylic CIEM shells and solid-silicone CIEM shells (not that I would anticipate anyone using vented BAs within a solid-silicone shell, but my point is just that some people may be hearing vented BAs in acrylic CIEMs and comparing them to non-vented BAs in solid-silicone CIEMs, and drawing conclusions too simplistically).
 
 
Another factor is that solid-silicone CIEMs tend to also have silicone sound tubes/canals, rather than plastic tubes/canals, and I have seen it said that this may lead to a slightly more 'organic' sound (silicone is not as hard and reflective to soundwaves, as hard plastic or titanium tends to be). But there are also some benefits to using hard soundtube materials, as it can help propogate treble frequencies efficiently, for example. So, it's not that one material is always better than another, but the most appropriate material will need to be chosen according to the specific CIEM configuration (and desired sound character) being made/tuned.
 
 
I suggest you ask your question in this thread.
 

 

 

[Designdude]

Thanks for the response, I really appreciate it. I hadn't even considered the impact that a soft sound tube would have on the sound. I'm new to all this so the fine details are very much going right over my head.
 
Thanks again

 

[piotrus-g]

  Hi guys,
 
So, I have heard that hard acrylic IEMs produce superior sound over the silicone ones due to the cavity in the shell. Can anyone shed some light on this at all? I've heard some theories along the lines of the cavity allowing drivers to move more freely but I assumed that with balanced armature drivers the change in airflow wouldn't really change as they have metal casing.
 
I'm new to all this so I would really appreciate any input from people that have a better understanding of the tech.
 
Thanks. =)

Having experience with both materials and how they affect sonic properties I think I can help you with that.
 
Drivers in hollow acrylic shell behave differently then in full silicone. The main disadvantage of hollow acrylic and advantage of silicone is that driver enclosed in solid silicone shell has less ringing as silicone works as suspension for the driver/s. Driver in acrylic even if it's glued to the shell will still rattle a little bit more compared to silicone.
 
Main advantage of hollow acrylic would be, as mentioned by @Mython , easy implementation of vented drivers which allows for higher bass quantity. Though, at the same time venting always increases THD of the driver so it's a trade-off.
 
Which are better? There's no clear win in my opinion. Both materials are used in IEM industry sucessfully for years.
It's sort of like Turbo-charged vs NA engines in cars - you've got two groups of supporters and everyone is right

 

[Designdude]

Having experience with both materials and how they affect sonic properties I think I can help you with that.

Drivers in hollow acrylic shell behave differently then in full silicone. The main disadvantage of hollow acrylic and advantage of silicone is that driver enclosed in solid silicone shell has less ringing as silicone works as suspension for the driver/s. Driver in acrylic even if it's glued to the shell will still rattle a little bit more compared to silicone.

Main advantage of hollow acrylic would be, as mentioned by @Mython , easy implementation of vented drivers which allows for higher bass quantity. Though, at the same time venting always increases THD of the driver so it's a trade-off.

Which are better? There's no clear win in my opinion. Both materials are used in IEM industry sucessfully for years.
It's sort of like Turbo-charged vs NA engines in cars - you've got two groups of supporters and everyone is right

Thanks for the information!

Apologies for coming back so late with a reply on this. It's interesting to see the different opinions on this. I guess, like you say, a lot of it comes down to personal preference.

Cheers

DD

 

[piotrus-g]

Thanks for the information!

Apologies for coming back so late with a reply on this. It's interesting to see the different opinions on this. I guess, like you say, a lot of it comes down to personal preference.

Cheers

DD

No worries! Some time ago I took on THD measurements and there was a clear difference between driver enclosed in silicone and driver in hollow acrylic. Silicone encased driver presented between 2 to 4 times lower THD across the spectrum! So the difference is huge actually.
There's also a difference in THD measurements between hollow acrylic when driver is glued to the wall of the shell and when it's only hanging on the tubing (some companies do that), there's also a minor difference in THD when the shell is open back (for example during assembly) and when it's closed.

We could argue if the lowest THD is correct objective when tuning the IEM. Because low THD drivers could sound too precise.

TL;DR: there's measurable difference in CSD and THD between same drivers in different materials and the outcome is only a matter of taste.