Recommendation for Ear simulator kits for IEM measurement

[Earfonia]

Do you mean by measuring the voltage output from the microphone and do the math?

 

[SIY]

Do you mean by measuring the voltage output from the microphone and do the math?

Pretty much, though your software might do the math for you.

 

[pwjazz]

For less critical application where super high accuracy measurement is not required, can we estimate coupler microphone SPL calibration using IEM factory specs like for example, specification of Etymotic ER2XR:

Sensitivity (@1 kHz) SPL at 0.1v : 96 dB

https://www.etymotic.com/er2-new.html

Can I calibrate my coupler mic SPL reading by the following steps:
I use REW:
1. Set playback tone: 1kHz.
2. Split the headphone output to ER2XR and True RMS voltmeter.
3. Set REW playback volume to ER2XR at exactly 100 mV / 0.1V measured at voltmeter.
4. Calibrate the SPL reading on REW SPL Meter to 96 dB SPL.

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Is the definition of IEM sensitivity specification, is the SPL reading from standard measurement equipment like IEC 60318-4 coupler + calibrated microphone?

Thank you! Sorry many questions

If you have access to a calibrated handheld SPL meter, you might be able to take measurements of nearfield speakers with both that and your mic and calibrate to that...

 

[JohnYang1997]

I know that I'm little late on this. But firstly your choice is fine. It's a standard coupler and AP also endorses David Larson.
I would recommend ra0045 coupler or bk 4195. Aco japan also offers some cheaper alternatives. All complying to the standard.
On the standard, there's still only one iec711, aka, iec60318-4 standard, that's the old one. There's no other standard at this moment. Also the peak at 13.5k is desirable.
To see if you get the correct response just hook up a pair of er4s and compare to the manufacturer provided response which is measured on gras ra0045. Never ever use the newer hires/high frequency couplers. They suck. However this doesn't mean that the ra0045 is perfect. The couplers only actually works with deep inserting types like CIEMs and etymotics. You need to measure a lot of earphones to really get the intuition of the coupler. And what they are able to tell you. Some information you need experience to extract. On the other hand the new hires couplers remove the information altogether so that it always looks good which is plain wrong.
I don't want to spend too much time on this but you should get the idea.

 

[Earfonia]

Pretty much, though your software might do the math for you.

If I understand it correctly, the software only can do the math when the whole system is well integrated, meaning:
- We can input the mic sensitivity value into the software
- We can input the mic pre-amp gain and the audio interface input sensitivity value into the software

Without those number how the software knows how to calculate the SPL value? And with REW I simply don't know how to input those values into REW. Please correct me if I'm wrong. Or probably there is another software where we can input those values. Thanks!

So to me, measuring the output of the mic seems a simpler process if we know the exact value for the mic sensitivity that usually expressed in dBV / Pa or mv / Pa @ 1kHz . And since 94 dB SPL is 1 Pascal, so we just adjust the input loudness to get the exact millivolt or dBV value out from the mic connector.

If you have access to a calibrated handheld SPL meter, you might be able to take measurements of nearfield speakers with both that and your mic and calibrate to that...

Yes, I tried that. The problem is with my plinth type of ear simulator, the mic is integrated inside the coupler, so I'm not really sure where or how deep is the microphone from the opening lid of the coupler. I tried and couldn't get an accurate calibration, around +/- 2 dB of error.

I know that I'm little late on this. But firstly your choice is fine. It's a standard coupler and AP also endorses David Larson.
I would recommend ra0045 coupler or bk 4195. Aco japan also offers some cheaper alternatives. All complying to the standard.
On the standard, there's still only one iec711, aka, iec60318-4 standard, that's the old one. There's no other standard at this moment. Also the peak at 13.5k is desirable.
To see if you get the correct response just hook up a pair of er4s and compare to the manufacturer provided response which is measured on gras ra0045. Never ever use the newer hires/high frequency couplers. They suck. However this doesn't mean that the ra0045 is perfect. The couplers only actually works with deep inserting types like CIEMs and etymotics. You need to measure a lot of earphones to really get the intuition of the coupler. And what they are able to tell you. Some information you need experience to extract. On the other hand the new hires couplers remove the information altogether so that it always looks good which is plain wrong.
I don't want to spend too much time on this but you should get the idea.

Thanks! I've read your opinion regarding the new High Res coupler here:
https://www.audiosciencereview.com/...close-to-harman-curve.8029/page-5#post-198084

Yes, we are looking for a more affordable solution, and the ear simulator from ACO looks interesting:
http://www.aco-japan.co.jp/eng/sound/type2128/type2128.html

Any model you could recommend from the link above? Thanks!

 

[SIY]

I haven't tried a REW calibration with an actual test mike (it seems to be set up for USB mikes), but with other software (e.g., the Virtins Multi-Instrument I most often use with sound cards), it's a pretty easy process as long as you apply a tone, measure the mike output voltage with a meter (most DMMs are fine at 400 Hz) the way you described, calculate the SPL, then enter the info into the calibration panel; there's nothing magic about 94dB except not having to do a ten second calculation to convert voltage to SPL.

Be careful to note the soundcard's mike gain setting, because you'll always need to return to that in order for the calibration to remain valid.

 

[JohnYang1997]

Those couplers should perform the same. The external polarized may last longer due to the charge will always be recharged. The prepolarized don't need 200V polarization voltage. But generally it will stay performing the same for long periods of time. You may lose some low end response when it's discharged. But don't worry, that happens over a long time. I personally have not used the Aco Japan one. But I don't think they would be any worse either. They are certainly not too cheap on the other hand.
Some Chinese couplers like rstech are pretty good too, I have one, measuring basically the same as ra0045. I have used ra0045 and 4195 as well as 4128c when I was visiting Moondrop in 2018.

 

[Earfonia]

Some Chinese couplers like rstech are pretty good too, I have one, measuring basically the same as ra0045. I have used ra0045 and 4195 as well as 4128c when I was visiting Moondrop in 2018.

Do you mind to share link for the rstech Chinese couplers? Thanks!

 

[JohnYang1997]

Do you mind to share link for the rstech Chinese couplers? Thanks!

http://www.rstech.com.cn/goods!changeLanguage.action?flag=en&pid=fbb92eaa57642edd015764775a30000c
Mine was not directly bought from them but a second hand.

 

[Earfonia]

http://www.rstech.com.cn/goods!changeLanguage.action?flag=en&pid=fbb92eaa57642edd015764775a30000c
Mine was not directly bought from them but a second hand.

Does the Artificial Ear Type AE4000 come with external polarized or prepolarized microphone?
If external polarized means we have to buy the Power supply for the 1/2 inch Preamplifier (e.g. RStech power supply module PM2000-S) ?

Thanks!

 

[Earfonia]

I would like to ask opinion on IEM measurement, is it better to measure the IEM with small ear tip (11mm) or medium ear tip (12mm) ?

In the past I used to measure IEM with medium ear tip (12mm) but it seems that the small ear tip (11mm) gives better fit and re-insertion consistency. So for the past 2 years or so, I've been measuring using the 11mm ear tip.

My observations are as the following:
1. My IEC 60318-4 coupler opening diameter is 11mm.
2. 12mm ear tip sometime slide out over time. For example, if tonight I insert the IEM into the coupler using the 12mm ear tip and measure, then leave the IEM in the coupler overnight, the next day it will slide out a bit from the coupler resulting slightly different measurement result. While with 11mm ear tip the IEM stays in the same place and the measurement result is consistent.
3. With 11mm ear tip it is easier to do consistent insertion depth for repeated measurement with repeated re-insertion. Because it fits better in the coupler.

My question is, is the IEC 60318-4 coupler designed for 11mm or 12mm ear tip?

@JohnYang1997 and @SIY do you have any opinion?
And anyone else who has any info about it.
Thanks!

Small 11mm ear tip insertion:

Medium 12mm ear tip insertion:

 

[anli]

Can not understand the way all theese couplers supply stable insertion depth. Do they do it some way?

The thing is, own experiments force me think even small insertion depth difference results in very different peaks/dips on the FR plot.

In other words, can anybody get two equal FR with IEM reinsertion between them? Long hard practice?

 

[RHO]

Can not understand the way all theese couplers supply stable insertion depth. Do they do it some way?

The thing is, own experiments force me think even small insertion depth difference results in very different peaks/dips on the FR plot.

In other words, can anybody get two equal FR with IEM reinsertion between them? Long hard practice?

I think the way they do it is looking at the resonance the coupler has. This shows up as a peak in the FR in the treble. Reviewers align that peak for every IEM they measure. (I think Crinacle and Super*reviews align @ 8kHz) This way they have some kind of standard to compare results.
At least that's the way I understand they do it.
How you can compare results between different couplers ... no idea. I think it's the same problem as comparing OE measurements between different rigs.

 

[anli]

resonance the coupler has

Probably more handy to say about a system: coupler + (IEM with eartip). I guess, peaks/dips places/levels are defined by the system in a whole rather a coupler alone: different FR take place depending on insertion depth.

 

[RHO]

Probably more handy to say about a system: coupler + (IEM with eartip). I guess, peaks/dips places/levels are defined by the system in a whole rather a coupler alone: different FR take place depending on insertion depth.

Yes, correct.
The resonance shifts with insertion depth.

 

[staticV3]

Klippel apparently sell the 43AC-S1 for 4210€ excl. shipping, taxes, handling etc according to their QC system price-list.