[mgsu]

First, let's prove that FiR system is not a bass-kinetic port.

1. Take the IEM out of your ear.
2. Close the nozzle with your finger.
3. Put the port close to your ear.
4. Listen to music. Try putting it close to different parts of your ear if you want.

Now what do you hear?

Thank you for bringing this up. Had the same question swirling in my head.

You are right, when you close the nozzle, you hear just the midrange. Tried to put it against my ear, to hear if it does something. Nada.
The sound that comes out of the port is quite faint.
To say that FIR has some sort of bone conduction from this port is just an overstate. To me it looks more likely that FIR RN are open back design, nothing more.

 

[Leonarfd]

634ears Miroak-II Cocobolo, single DD IEM from boutique maker in Japan.

Shared some small thoughts when I got it, Miroak-II stay now within my top 5.

Musical and organic timbre, its warm and detailed.
Bass can fulfil most peoples lust for fun, its big and textured and can really slam.
Mids that are also on the thicker side, vocals and instruments are detailed and full.
Treble is also not veiled and dark, its open and give a good balance to the fuller bass and mids.
Soundstage and imaging is maybe the thing being average, but in a way suits the more organic sound of Miroak-II.

Also very happy that I did go for the cocobolo wood, as he explained it had very good balance for this type of driver.
Musashi is an excellent maker, looking forward to more from him.

And also a shout out to my friend @Matchi, thanks for the awesome cable you made for it.
Type 6 litz copper. You rock my friend and I look forward to more cables.

 

[aaf evo]

Thank you for bringing this up. Had the same question swirling in my head.

You are right, when you close the nozzle, you hear just the midrange. Tried to put it against my ear, to hear if it does something. Nada.
The sound that comes out of the port is quite faint.
To say that FIR has some sort of bone conduction from this port is just an overstate. To me it looks more likely that FIR RN are open back design, nothing more.

FiR doesn’t use a bone conduction driver at all. It’s just a way of “bone conduction” by exposing the DD to your ear more or less. I can see how it’s misleading but just reading the website and well.. the driver configuration, it’s evident it’s not the same technology at play.

With that said there was definitely an improvement in sound between the universal and CIEM Frontier series IEMs. Whether that’s down to the bass port being up close to the ear or just the difference between having a perfect fit compared to a universal… who knows?

You won’t ever get that same holography in the stage or image from any of the kinetic bass IEMs the way you would with some of the UM and EE IEMs.

 

[sorrick]

There were a lot of customer concerns with the Odyssey about asymmetric vibration levels between R/L units when doing this type of testing.

IIRC Jack/EE clarified that the BCD unit is hand mounted on the shell so there is expected variation in the shell interaction this shows, but this isn't in fact the mechanism the BCD uses (the driver is aimed the other direction) and is simply a byproduct of manufacturing that won't affect sound.

Yes, my understanding with the EE BCDs is that they are designed to direct the vibrations to the exterior of the nozzle and get transmitted via contact between silicon ear tips and the ear canal, which was the reason that foam tips do not work with the bone conduction. My understanding is that different bone conduction implementations work differently—for example I believe that other companies bcds rely on physical contact between the shells and the concha. IIRC this came out in the tiff between UM and EE over BCDs because the two relied on different approaches for the bone conduction. I have no specific expertise to be able to confirm or refute any of this, though I would certainly say anecdotally that EE’s BCD implementation in EVO and Odyssey certainly seem to add a noticeable depth and dimensionality as well as physicality to the sound.

 

[haci]

Yes, my understanding with the EE BCDs is that they are designed to direct the vibrations to the exterior of the nozzle and get transmitted via contact between silicon ear tips and the ear canal, which was the reason that foam tips do not work with the bone conduction. My understanding is that different bone conduction implementations work differently—for example I believe that other companies bcds rely on physical contact between the shells and the concha. IIRC this came out in the tiff between UM and EE over BCDs because the two relied on different approaches for the bone conduction. I have no specific expertise to be able to confirm or refute any of this, though I would certainly say anecdotally that EE’s BCD implementation in EVO and Odyssey certainly seem to add a noticeable depth and dimensionality as well as physicality to the sound.

from parallel discussion in EE thread:

I asked gpt-4, and here is what they have to say -)

If you were to use a traditional ear or coupler simulator with a microphone to measure the frequency response of an IEM that employs both air and bone conduction, you might encounter the following anomalies:

1. **Incomplete Bass Representation**: Since bone conduction is often efficient at transmitting lower frequencies, and if any part of those vibrations couples into the air inside the ear simulator, there might be an unexpected emphasis in the bass region. However, this emphasis would not capture the full extent or quality of the bass delivered via bone conduction.

2. **Mismatched Phase Interactions**: If the bone-conducted vibrations influence the air inside the ear simulator, they might interfere with the sound from the air conduction driver. This could lead to unexpected peaks or dips in the frequency response due to phase interactions. However, this representation might be inconsistent and might not accurately reflect the listening experience.

3. **Reduced High Frequencies**: Bone conduction is generally less effective at transmitting higher frequencies compared to air conduction. While the microphone would pick up the highs from the air conduction driver, it wouldn't capture the reduced high-frequency response from the bone conduction, leading to an over-representation of high frequencies.

4. **Ambiguous Results**: The interference between the air-conducted sound and any bone-conducted vibrations that enter the air space of the simulator might lead to ambiguous or inconsistent results, especially if the measurement is repeated multiple times or with different placements.

5. **Potential Resonances**: The combination of both conduction methods and the coupling of bone-conducted vibrations into the air might introduce or amplify specific resonances, leading to unexpected peaks in the frequency response.

It's important to stress that while these anomalies can give some insights, the measurements would not provide a full or accurate representation of the IEM's performance, especially the contributions from the bone conduction driver. To get an accurate understanding, a more specialized measurement system that can capture both air-conducted and bone-conducted sound would be required.

 

[Animagus]

Hey guys! Looks like it's bone conduction quad-brid fest in my house. Here's my review of BGVP Phantom, their latest 2DD + 2BA + 2EST + 2BCD quad-brid IEM. AFAIK, this is the cheapest BCD quad-brid in the market at $900 and quite a good one at that. I particularly loved how it is able to present an engulfing soundstage with good depth, depth layering and strong instrument definition and imaging. What's also cool is that it has thermochromic dyed wood shells that change to a lighter colour once they come in contact with the skin - something which might not be to everyone's liking but maybe the wood shells would be since this is a stock design and it's great that BGVP aren't charging any extra for them. Read on to know what I think and let me know if you have questions or would like comparisons with any other IEMs. Cheers!

BGVP Phantom

​

 

[Animagus]

Hadn't logged in in 2 days and just caught up with all the BCD talk in the thread. I'll just post a paragraph of mine from the BGVP Phantom review that talks about 3 different types of BCD drivers in 3 different IEMs - UM Mest MK2, Kinera Loki Emerald and BGVP Phantom.

Most of the BCD IEMs in the past have all used a different type of BCD driver and implemented them differently in their IEMs with a combo of DDs, BAs and EST drivers. Unique Melody used a piezoelectric bone conduction driver in their MEST IEMs that was implemented under the faceplate, Kinera developed their own high output BCD in house that was implemented more like a DD and BGVP instead chose to go with Sonion’s dual BCD driver that is a block shaped driver and bursts the vibrations out its spout-less opening. So, in case of Phantom, the driver needs to be implemented at the inner wall of the IEM that faces the concha and transmits the vibrations via a vent opening in the inner wall.

 

[haci]

I urge someone with expertise to just open up the shells, disabling the BCD and do comparisons. Please

For EE IEMs one thing you can try is to put on foam tips (not good conducters for BCD) and switch with silicone (good BCD conductor) for comparison.

 

[Alpexis]

Curious how many of you have searched and found your 'one and done' iem. Including selling off all the rest of your gear and never looking back. (with respect to those of you who don't believe in the 'one and done' approach to this hobby)

 

[Animagus]

Curious how many of you have searched and found your 'one and done' iem. Including selling off all the rest of your gear and never looking back. (with respect to those of you who don't believe in the 'one and done' approach to this hobby)

To be honest, I have quite a few IEMs and headphones that I could just keep using and stay happy and content with forever if I really wanted to but it's the curiosity of trying everything that is out there and all that is possible that keeps me intrigued and excited. It's not only audio for me. I'm the same when it comes to guitars, amps and other music instruments/pro-audio gear as well as with cars and motorbikes. What doesn't help is that I'm a music and audio industry guy and my life kinda revolves around music and audio gear day in day out. So all the interests combined is why I don't have a big savings account but a massive collection of gear in my house. Not the most sane way to live if I may add.

 

[dleblanc343]

Regarding BCD, I had the chance to try MEST MK3 prototype with switch for a solid 20 minutes and the differences were there but not as dramatic as I was expecting — but definitely a welcome effect when heard.


The switch wasn’t even labelled so you had to trust your ears to know if It was on or off — which was a nice challenge that a few who tried straight up guessed wrong.

BCD active added note contour and helped notes linger for a few more milliseconds in certain instrument reproductions vs it being off.

The effect is akin to switching between Sharp and Slow Roll-Off on your DAC chip, but slightly more substantial.

It was most apparent on strings and wind instruments that had more presence and realism of them being life-like. Percussion such as drums also had a bit more sustain, but this wasn’t as drastic.

To my ears, the BCD was most apparent to my ears in the overtones/ harmonics of 1 to 4/5 kHz.

This being said, the MEST MK3 doesn’t have a BCD of the same caliber of UM’s higher models so perhaps there’s variance there as well.

 

[maegnificant]

Theoretically if you have no damage to your inner ear, especially the cochlear hairs, the stimulus reaching your auditory nerves should be the same whether it comes from a driver within the earpiece of an iem or from a conduction driver radiating sound waves through bone to that nerve. But this is basically never the case. We all have some blockages in our outer ears and damage in our inner ears simply from living, not to mention anatomical anomalies, etc. Theoretically, the waves reaching the auditory nerve through bone conduction bypass any of these irregularities and could, again theoretically, be a "cleaner" way to reach the nerve. There are bone conduction headphones already - I am sure you have seen or heard them - the conductor/earcup rests not in/on your ear but on the bone of your skull behind your ear They are remarkably good for what they are. So the tech exists, it's real, it's just a question of whether it "enhances" the sound coming from an iem's other drivers. I imagine timing is an issue vis a vis the other drivers. Also, as has been discussed, the materials through which the sound waves must pass before finding bone is also an issue. I can see it as a stand-alone application - pure BCD iems - but when it's paired with other driver types and it covers some of the same frequency range as those drivers, I'm not entirely sure what it's meant to do. If anything it reinforces those frequencies but it may also have a different sound given that it bypasses some of the aforementioned irregularities yet at the same time introduces new potential influences on the sound like the IEM material and human bone into the mix.

All the exclusive bone conduction stuff I saw is actually placed above the ear.

 

[mgsu]

Curious how many of you have searched and found your 'one and done' iem. Including selling off all the rest of your gear and never looking back. (with respect to those of you who don't believe in the 'one and done' approach to this hobby)

After one month of reading through reviews, i picked up the FIR RN6. It was a blind buy. I was indecisive between Noble Sultan and FIR RN6.
I think i am now set for the next years to come.

 

[Auricon]

Despite some teething issues, the shine hasn't diminished too much with my N30LE. Otherwise new music discovery Friday with Teddy Swim's latest.

P+ / Class AB / Tube "Classic" timbre is just what the 109 Pro ordered – big sounds, warm bassy beats into the weekend.

Have a groovy weekend my friends!

 

[blotmouse]

Curious how many of you have searched and found your 'one and done' iem. Including selling off all the rest of your gear and never looking back. (with respect to those of you who don't believe in the 'one and done' approach to this hobby)

I don't know if anyone here that's heard a bunch of TOTL stuff has ended up one-and-done? 3 and done maybe, lol.
All I see are folks proclaiming done and then a few months later "Welcome back, friend". Such is the way.