[hakuzen]

@CoiL , you could use 8, 10, 12kHz or even higher resonances, but the mics you are using are reliable till 10kHz (and this going high). a decent chinese true precision 1/2" mic, reliable till 10kHz (in theory), use to cost around $90. till 16kHz, ~$135. till 20kHz, >$200.

Like I said earlier, I think shooting for an 8 kHz resonance peak is a really bad idea. If you create graphs this way, you could make two dissimilar IEMs look to have similar treble performance. That's just misleading.

And what are you going to do with the Zero Audio Carbo Tenores? Which peak are you going to move to 8 kHz??

This would only makes sense if you carefully adjust the insertion depth (with extra-length eartips) for each and every IEM you listen to, in order to make sure you always hear a peak at 8 kHz. And if you do that, you're nuts. IMHO.

you are right. different iem are built different way: longer wide nozzles vs short narrow ones, different tuning, etc. and the length of the tips you are using also alter the distances, like you and castleofargh have told.
it was just a tip for people using tubes, to get an idea of an approximated length of the tube.
there are some iems where you can't find 8kHz peak. i use to check 6, 8, 10, and 12kHz resonances (one of them will be present for sure). but sometimes, you can't center any of them by modifying insertion depth (which is limited) in a 711 coupler.
in these cases (and in the cases that adjusted insertion depth is completely unrealistic), i simply use the depth i'd use in my ears, approximately.
so trying to balance an arbitrary norm with realism and common sense. this is a hit and miss game..

 

[ForceMajeure]

So this is going to be one of those threads when a miss a few days and there is already 4 pages and walls of text...

regarding the iem slipping from the coupler or needing holding it. there aren't dozens of solutions to it.
Sometimes even with the same tips on different iems, some will have a tendency to come out and break seal. Partly due to geometry of the nozzle/iem resting on the table and also partly due to pressure from a the seal pushing the iem out.

@hakuzen with your latest gear you might want to try and use the coupler horizontally, create a leveling mini table so the iems is at the same height as the coupler entry. Then use some significant amount of blue tack against the back of the iem so it doesn't slide out during measurement. that way you could avid holding it completely

Basically switching to horizontal measurements like you used to do with the previous iec711 versions you had or imm6
Hopefully the weight of your fancy coupler should help so it doesn't move as well

 

[perfecious]

Ok, now that's a strange synchronicity/coincidence. I kinda started a similar conversation yesterday in Crin's thread, and all of a sudden, there is a separate thread (made before my posts), discussing the same thing. That's kinda... strange, and awesome at the same time. Is the collective consciousness of the community synchronizing or something? LOLz Anyway, I've made a few posts about the use of 8kHz resonance point, and how it actually is not ideal/correct IMO. Will probably post about this topic here in the future, once more info comes out from more people.

 

[hakuzen]

So this is going to be one of those threads when a miss a few days and there is already 4 pages and walls of text...

regarding the iem slipping from the coupler or needing holding it. there aren't dozens of solutions to it.
Sometimes even with the same tips on different iems, some will have a tendency to come out and break seal. Partly due to geometry of the nozzle/iem resting on the table and also partly due to pressure from a the seal pushing the iem out.

@hakuzen with your latest gear you might want to try and use the coupler horizontally, create a leveling mini table so the iems is at the same height as the coupler entry. Then use some significant amount of blue tack against the back of the iem so it doesn't slide out during measurement. that way you could avid holding it completely

Basically switching to horizontal measurements like you used to do with the previous iec711 versions you had or imm6
Hopefully the weight of your fancy coupler should help so it doesn't move as well

thanks for the heads up!
i've tried. same result. got best results when the contact surface and pressure of the press/table/whatever over the iem was minimum, regardless of rigidity of the press material (same result when using zero, a bit, or a ton of putty/soborthane).
guess i found the quiz: any press used to hold the iem, creates noticeable noise and lows distortion, if the press stand is separated from the coupler stand. that's why got the best improvement when isolating the press stand with soborthane feet (no improvement by just touching/joining press stand to coupler stand).
the press mechanism in pro rigs is attached to the heavy coupler stand. minimum noise added.

so i've had to get the press and stand apart, and use an adhesive tape or some putty to hold the iem into the coupler. simple, easy (although the press was easier/faster), and effective.

 

[CoiL]

Like I said earlier, I think shooting for an 8 kHz resonance peak is a really bad idea. If you create graphs this way, you could make two dissimilar IEMs look to have similar treble performance. That's just misleading.

And what are you going to do with the Zero Audio Carbo Tenores? Which peak are you going to move to 8 kHz??

This would only makes sense if you carefully adjust the insertion depth (with extra-length eartips) for each and every IEM you listen to, in order to make sure you always hear a peak at 8 kHz. And if you do that, you're nuts. IMHO.

Exactly my thoughts.

@CoiL , you could use 8, 10, 12kHz or even higher resonances, but the mics you are using are reliable till 10kHz (and this going high).

Ok, I quite belive that iMM-6 is reliable up to 10kHz but what about producer claimed 20-20kHz calibrated accuracy? And why it is only accurate up to 10kHz when measuring IEMs?

Ok, now that's a strange synchronicity/coincidence. I kinda started a similar conversation yesterday in Crin's thread, and all of a sudden, there is a separate thread (made before my posts), discussing the same thing. That's kinda... strange, and awesome at the same time. Is the collective consciousness of the community synchronizing or something? LOLz Anyway, I've made a few posts about the use of 8kHz resonance point, and how it actually is not ideal/correct IMO. Will probably post about this topic here in the future, once more info comes out from more people.

Please do post here too, would be interesting to read different thoughts about measuring.

 

[hakuzen]

Ok, I quite belive that iMM-6 is reliable up to 10kHz but what about producer claimed 20-20kHz calibrated accuracy? And why it is only accurate up to 10kHz when measuring IEMs?

accuracy refers to error tolerances. of course iMM-6 can read above 10kHz, but error margin grows up above norm tolerances. like always, a matter of accuracy and $$$.
the 20-20kHz "calibration" file i received with iMM-6 (my gratitude to the manufacturer for providing it on digital media) was a bad joke. ridiculous.

 

[Otto Motor]

For people who don't think FR graphs don't give much info: here two earphones with totally different tuning. That low-end difference is real!

 

[Otto Motor]

Fidue have a production issue on hand with the A65: my first pair from early last year had a pronounced channel imbalance. The warranty replacement that arrived yesterday has an even bigger channel imbalance.

FR pair 1

FR pair 2

 

[CoiL]

Will leave my calibration like that. Don`t bother to mess with it anymore. Should be "accurate" enough and fill its purpose - comparing IEMs within my setup.

Will add other IEM measurements later (when I have free time).to my measurements post & gallery.

 

[Kitechaser]

I just measure at night and hope not to fart

I was wondering where the supposed enhanced bass went.

 

[chickenmoon]

Starting experimenting with Dayton IMM-6: https://www.head-fi.org/threads/tanchjim-oxygen-impressions-thread.901366/page-17#post-14916986

 

[Otto Motor]

Here my settings for the REW software...based on the experience of many uses at another forum (I only copied them). Excuse the large size of the images.

 

[Otto Motor]

Question: I am measuring a few really big channel imbalances in some multis. Using different cables makes no difference. Imbalances up to 8 dB are consistent up into the treble.

When swapping channels/earpieces, the earpiece that was ahead by 8 dB is now 8 dB behind, which points to a problem with the source.

Could it be that a slight channel imbalance in an earphone with a weird impedance profile is grossly amplified but the "wrong" amplifier? This theory is supported by the fact that single DDs (with flat impedance profiles) do to show these imbalances.

 

[csglinux]

Question: I am measuring a few really big channel imbalances in some multis. Using different cables makes no difference. Imbalances up to 8 dB are consistent up into the treble.

When swapping channels/earpieces, the earpiece that was ahead by 8 dB is now 8 dB behind, which points to a problem with the source.

Could it be that a slight channel imbalance in an earphone with a weird impedance profile is grossly amplified but the "wrong" amplifier? This theory is supported by the fact that single DDs (with flat impedance profiles) do to show these imbalances.

I use the Hugo 2 as the driver for most of my measurements, because it has very good SINAD and very low z-out. Most sources should be ruler-flat into an infinite-impedance load, but if your headphones have wild impedance swings with frequency, then who knows?! I know some people like the sound of Schiit units, but they don't usually measure all that well. I know the Fulla's spec is 0.5 Ohm z-out, but it does sound like that's the source of your channel imbalance.

Most modern DAPs can be used in USB-DAC mode these days. Maybe you can try something like that instead of your Fulla amp?

 

[castleofargh]

Question: I am measuring a few really big channel imbalances in some multis. Using different cables makes no difference. Imbalances up to 8 dB are consistent up into the treble.

When swapping channels/earpieces, the earpiece that was ahead by 8 dB is now 8 dB behind, which points to a problem with the source.

Could it be that a slight channel imbalance in an earphone with a weird impedance profile is grossly amplified but the "wrong" amplifier? This theory is supported by the fact that single DDs (with flat impedance profiles) do to show these imbalances.

super pro tip: as a general rule, I always use the same amp channel to measure each side of an IEM, to be sure that whatever change I measure doesn't come from the source/amp.

now for your specific situation, are the 8dB a global variation like you'd get from changing the volume level, or does it change with frequency? you seem to talk about testing other IEMs the same way and say that flat impedance IEM does not show such variation. so I imagine that you mean there is a deviation from other multi BA? if so, is it the same deviation or does it seem to follow the impedance curve of those IEMs(if you happen to know it)?
I'm asking something strange in this thread, but showing some of those measurements might help^_^.

side question, do you get the same deviation into that IEM at a lower volume output(digital attenuation as well as trying lowering the amp's volume)? that to check that you're not "over-driving" or clipping the sine sweep. did you check the amp "unloaded" directly into a line in/mic in input? and is there any imbalance?
8dB is a lot for amp imbalance if there is nothing else wrong with it. even at the worst position of the little Shure volume control cable, I don't think I can get that much out of my IEMs. and my second worst is my O2 with up to 0.5dB more on one channel but only at specific positions of the volume knob(that I avoid like a plague).