[Brooko]

What was the IEM measured? 20dB delta between peak and trough in the first measurement seems less likely than the 12 or so in the second one

 

[Slater]

What was the IEM measured? 20dB delta between peak and trough in the first measurement seems less likely than the 12 or so in the second one

I’ve been using the KZ EDR1 for all of the coupler testing.

EDR1 is a nice simple v-shaped single dynamic that I’m quite familiar with, no mic, same side tested every time, same ear tip, same insertion depth. I also enable airplane mode, to eliminate any possible radio interference.

And when I am doing these back to back tests, I am redoing both the baseline and the experimental test, to negate variables like temperature or humidity. If I don’t do that, I’ve found there can be slight variations in my baseline runs on different days (which I am attributing to factors out of my control). So for example, a measurement taken with the EDR1/syringe coupler a week earlier and the same setup today will have slight variations of 1-2dB here or there.

BTW, the one titled 10mm is the shorter silicone one you recommended I try

 

[bartzky]

@Slater: Do you have some other IEMs? Preferably a few ones that have already been measured in IEC setups?

 

[Slater]

Yes, I have numerous IEMs (including models that you have measured - KZ ATE, ATE-S, HDS3, ZS3, ZST, ZS6, ED9, Xiaomi Pro HD). I can repeat my testing using some of the models you have tested, so I can compare my results with yours.

1). Even though I don't have the same couplers as you, which of your coupler configiratons should I compare - your old Vibro Labs Veritas or your new setup?

2). How do I ensure my testing is at 90 dB @ 500 Hz? I do not see any such options in the configuration of AudioTools:

 

[bartzky]

1). Even though I don't have the same couplers as you, which of your coupler configiratons should I compare - your old Vibro Labs Veritas or your new setup?

Definitely the new setup. It's IEC compliant.
The most important thing is that the frequencies of the resonance peaks align. You can move the peaks by changing the dimensions of your rig's tube.

2). How do I ensure my testing is at 90 dB @ 500 Hz? I do not see any such options in the configuration of AudioTools:

It isn't simple. You'd need to know your mic's sensitivity and so on.
Though if you have got a multimeter I could tell you which level you're actually measuring at, if I've already measured the IEM in my new system. You could use that for a calibration of your system, if your app supports such an option.

 

[Slater]

Definitely the new setup. It's IEC compliant.
The most important thing is that the frequencies of the resonance peaks align. You can move the peaks by changing the dimensions of your rig's tube.

OK, that is helpful to know. Thanks

It isn't simple. You'd need to know your mic's sensitivity and so on.
Though if you have got a multimeter I could tell you which level you're actually measuring at, if I've already measured the IEM in my new system. You could use that for a calibration of your system, if your app supports such an option.

Yes, I have a multimeter.

The microphone I am using is the Dayton Audio iMM6 is that helps.

Also, I'm not sure why the above post didn't include the rest of the program options but they are here. Do you see anything in these options that is what you are looking for?

 

[bartzky]

Also, I'm not sure why the above post didn't include the rest of the program options but they are here. Do you see anything in these options that is what you are looking for?

The "microphone calibration" dialogue seems promising.
I suggest to find out the best tube length first. If the peaks align, you should try to write a simple calibration file. Likely your measurements will show a roll off at high frequencies that should be calibrated with such a file.
For testing I'd suggest to use a volume level you'd use for your personal listening. Volume level is not very important for frequency response measurements as long as it's high enough to surpass potential noise and low enough to not stress the DUT.
Though if you feel you need a constant and known volume level you could measure your voltage output with your multimeter. I could then tell you how loud the IEM will be. You should be able to do something with those numbers in the "microphone calibration" dialog. I guess adjusting "trim" or something... I'm not familiar with this app, though.

 

[Slater]

The "microphone calibration" dialogue seems promising.
I suggest to find out the best tube length first. If the peaks align, you should try to write a simple calibration file. Likely your measurements will show a roll off at high frequencies that should be calibrated with such a file.
For testing I'd suggest to use a volume level you'd use for your personal listening. Volume level is not very important for frequency response measurements as long as it's high enough to surpass potential noise and low enough to not stress the DUT.
Though if you feel you need a constant and known volume level you could measure your voltage output with your multimeter. I could then tell you how loud the IEM will be. You should be able to do something with those numbers in the "microphone calibration" dialog. I guess adjusting "trim" or something... I'm not familiar with this app, though.

The Dayton Audio iMM6 comes with it's own calibration file, specific to each unit's serial number. Would making my own calibration file be better than using the manufacturer's calibration file? Or are you saying to edit the existing calibration file, and make additional changes to the high frequency file (to counteract the treble roll off inherent in most of these FR mics)?

In the maen time, I will continue to experiment with tube length and diameter. Thanks so much for your advice and help!

 

[crinacle]

The Dayton Audio iMM6 comes with it's own calibration file, specific to each unit's serial number. Would making my own calibration file be better than using the manufacturer's calibration file? Or are you saying to edit the existing calibration file, and make additional changes to the high frequency file (to counteract the treble roll off inherent in most of these FR mics)?

In the maen time, I will continue to experiment with tube length and diameter. Thanks so much for your advice and help!

Dayton's calibration for the IMM6 is meant for free field use and not coupler use. Do not use that.

If you're looking for a calibration file to approximate IEC performance, the first 20 or so pages of this thread documents my efforts to understand them. There's about a 4dB boost in the midrange frequencies starting from 700Hz. Not even going to bother with the high frequencies considering their fickleness.

 

[Slater]

Dayton's calibration for the IMM6 is meant for free field use and not coupler use. Do not use that.

If you're looking for a calibration file to approximate IEC performance, the first 20 or so pages of this thread documents my efforts to understand them. There's about a 4dB boost in the midrange frequencies starting from 700Hz. Not even going to bother with the high frequencies considering their fickleness.

Well that sucks. If we have to make our own calibration files, why not just buy any old mic (like this one): https://www.amazon.com/Movo-MA1000-Omni-Directional-Microphone-Smartphones/dp/B017TJXC8G

 

[crinacle]

Well that sucks. If we have to make our own calibration files, why not just buy any old mic (like this one): https://www.amazon.com/Movo-MA1000-Omni-Directional-Microphone-Smartphones/dp/B017TJXC8G

Maybe. Never really looked into alternatives. I've been using the same microphone for more than a year, maybe I'll have a whack at it when mine eventually dies.

 

[bartzky]

The Dayton Audio iMM6 comes with it's own calibration file, specific to each unit's serial number. Would making my own calibration file be better than using the manufacturer's calibration file? Or are you saying to edit the existing calibration file, and make additional changes to the high frequency file (to counteract the treble roll off inherent in most of these FR mics)?

As @crinacle already explained the file is for free field calibration. Though it's useful to start with a mic that already has flat free filed response. So you might want to start with the provided file for your own calibration.

 

[Slater]

To all those with the Dayton Audio iMM-6 microphone -

Please be very careful with removing it from whatever coupler you use.

There's apparently a fine line between inserting it into a coupler (such as tubing) tight enough so that it provides a good seal, and one that does this:



And no, it can't be resoldered unfortunately, because the capsule is situated too far down into the metal cap (looks like about 10mm deep, and glued):



Oh well, it was nice while it lasted for 2 weeks...

 

[Raketen]

To all those with the Dayton Audio iMM-6 microphone -



And no, it can't be resoldered unfortunately, because the capsule is situated too far down into the metal cap (looks like about 10mm deep, and glued):



Oh well, it was nice while it lasted for 2 weeks...

If you have steady hands and fine tweezers there are some conductive epoxy/glue products that might work for this situation, OFC you will end up spending as much for the glue as the microphone itself

 

[ForceMajeure]

To all those with the Dayton Audio iMM-6 microphone -

Please be very careful with removing it from whatever coupler you use.

There's apparently a fine line between inserting it into a coupler (such as tubing) tight enough so that it provides a good seal, and one that does this:



And no, it can't be resoldered unfortunately, because the capsule is situated too far down into the metal cap (looks like about 10mm deep, and glued):



Oh well, it was nice while it lasted for 2 weeks...

I have warned anyone I could about that issue in the past. I hope your experience will serve as a lesson for new comers too. Thanks for the heads up and sorry for your loss.