[nmatheis]

Hi fellow headfi'ers!
 
I've been using the Dayton iMM-6 calibrated microphone with the Audtiotools iOS app for about a year now to generate and compare frequency response curves for IEM I purchase or get in for testing. It looks like nobody has created a thread for this, so I thought I'd man-up and create one to show you all how I use them. I thought a video tutorial would work well, so I shot a video today, uploaded it to my YouTube channel, and am embedding it below for those of you who'd like to learn how to use the iMM-6. A major caveat / disclaimer is that neither the iMM-6 nor the Audiotools app are not pro-level, and as such will not generate completely accurate, pre-level FR curves. What they will do is give you the ability to generate consistent FR curves at home for comparative purposes. By that, I mean that you can generate FR curves for IEM A and IEM B and then use the Audiotools app to overlay the FR curves normalized to 1kHz.
 
The FR curves you generate can be used for a few purposes...

• To help you learn more about your IEM by visualizing the basic sound signature as an FR curve
• To compare FR curves for multiple IEM
• To quickly check for / confirm channel imbalance issues in your IEM

 
Of course, the FR you generate don't tell the whole story. There's more to the listening experience than what a simple FR curve can tell you. I think we all know that, but IMHO FR curves are a basic tool that any of us can use to further our understanding and enjoyment of this hobby.  The Dayton iMM-6 + Audiotools app cost less than $35, so it's a pretty painless purchase with high bang for you buck factor!
 

 
Dayton iMM-6 Webpage
 
Dayton iMM-6 for $25 on Amazon
 
Audiotools iOS app Webpage
 
 
Video Tutorial

 
 
I hope that was useful for some of you. Let me know if you have any questions, and I'll do my best to answer!
 
Cheers,
Nikolaus

 

[hoerlurar]

interesting!
it would cost almost $40 for me to get one though, and i don't think i'm enough curious right now to get one.
 
well made video as well

 

[nmatheis]

interesting!
it would cost almost $40 for me to get one though, and i don't think i'm enough curious right now to get one.

well made video as well

Thanks for watching the video. If you ever do get one, come on back and add to the discussion!

 

[hoerlurar]

Have you compared your results to other measurements to see how they differ?
And have you tried different couplers as well, i guess they could have an impact on the measurements?

 

[nmatheis]

Have you compared your results to other measurements to see how they differ?
And have you tried different couplers as well, i guess they could have an impact on the measurements?

Since I'm not trying to generate standalone FR curves, I'm honestly not too worried about whether or not I can match other measurement rigs. I'm primarily using it to compare FR curves from different IEM against each other. For that purpose, I'm happy with the setup.

I'm sure I could find a different coupler that would better match the ear canal, but I don't think that's necessary for comparative data. In this case, the coupler is a constant. If others way to try different couplers or applying different correction files for more accurate standalone results, that would be something worth discussion for sure, though.

 

[Gunghouk]

Hi, I was wondering if you had tried different coupling lengths and compared the results?

I realise that it could be regarded as a being somewhat anal but I'm curious if the higher frequency wavelengths could be effected by sound path length variations, reflections and so subject to phase cancellations?

Do you use the Dayton calibration file in Audiotools? It's possible to use the cal file in the Android app Audiotool which could do the same as you've described.
Hmm.... I feel a Smaart experiment forming....

I know you're interested in comparative results but a little accuracy and precision never hurt anyone
Thanks
Neil

 

[nmatheis]

Hey Gunghouk. No, I haven't tried different lengths but could easily do that. I could also try different tubing. Just haven't done it yet. I was hoping others would give this a shot and chime in with their experience.

 

[Gunghouk]

I think I'll give it shot with Audiotool for Android and Smaart on the PC
Cheers

 

[nmatheis]

Cool beans. Please do and be sure to check back in!

 

[crinacle]

Just dropping by to share my measurements if you haven't seen it yet. Link's in my signature.

I prefer the white noise + decade graph as compared to the pink noise + octave smoothed one, so I decided to go for FFT Plot rather than Autiotools. Cheaper too, so it's a viable alternative.

My coupler is a 8mm inner diameter vinyl tubing. Snug fit and doesn't require tape or putty.

 

[nmatheis]

Bah! I'm mostly on mobile, so I don't see signatures very often. Can you just post a link?

 

[crinacle]

Here you go

 

[nmatheis]

Just dropping by to share my measurements if you haven't seen it yet. Link's in my signature.

I prefer the white noise + decade graph as compared to the pink noise + octave smoothed one, so I decided to go for FFT Plot rather than Autiotools. Cheaper too, so it's a viable alternative.

My coupler is a 8mm inner diameter vinyl tubing. Snug fit and doesn't require tape or putty.

I'm going to get that app and try measuring my IT03. One thing that would be helpful is if you could include which tips you used during measurement. Some IEM / tip combinations do adjust the frequency response enough to easily detect.

 

[shotgunshane]

What kind of tuning are you guys using? And how much? I'm going to try this portable set up.

 

[nmatheis]

What kind of tuning are you guys using? And how much? I'm going to try this portable set up.

I just use the IMM06 + iPhone 4S with AudioTools app. In the app, I eschew A or C weighting and measure the Raw FR. If you have questions once you get setup, just let me know here or via PM.