[CoiL]

Found this also:
https://reference-audio-analyzer.pro/en/report/dac/ibasso-dx-50-line.php
https://reference-audio-analyzer.pro/en/report/amp/ibasso-dx-50.php

So, despite hardware mods (that should improve measurements) and LO being 124ohm @ stock but measuring pretty flat, I should still go with HO @ low gain with measurements?
Just asking to be sure I understood correctly.

 

[castleofargh]

Found this also:
https://reference-audio-analyzer.pro/en/report/dac/ibasso-dx-50-line.php
https://reference-audio-analyzer.pro/en/report/amp/ibasso-dx-50.php

So, despite hardware mods (that should improve measurements) and LO being 124ohm @ stock but measuring pretty flat, I should still go with HO @ low gain with measurements?
Just asking to be sure I understood correctly.

yup, seems like the best option here. based on the link, you'll still have a little low freq roll off when using IEMs with low impedance in that range, but IMO that's not a big deal. we can easily create such variations with a more or less ideal seal. maybe warn when the IEM you're testing is known to have crazy low impedance, that the subs are probably a few dB higher if you think it's important.

 

[CoiL]

you'll still have a little low freq roll off when using IEMs with low impedance in that range

Those measurements are with stock capacitors (which are total crap and sq degrading) and opamps. I`m using technically much higher quality (cleaner) hardware upgrades (which subjectively take DX50 into totally new SQ level, imho) :
https://www.head-fi.org/threads/ibasso-dx50-mods.720776/page-20#post-12652071
What is interesting for me, is that when I compare LO vs. HO @ same calibration and measuring settings - whole HO bass area gets noticeably boosted (though, HOvs.LO vol level matched only by ear). But that was with high gain with ~30 Ohm 1xDD IEM. Will try with low gain and see if difference remains

 

[Otto Motor]

MKP plateau discrepancy between measurements: What has not been considered yet is plotting all the curves on top of each other. You may be surprised by the outcome and how the plateaus don't match in their magnitudes (Y-scale)....same with other areas. Next step would be "hearing" which one is true. Good luck with that one, too.

Since Headflux and we use the same software, it cannot be the software per se, but either the chosen settings or, more likely, the coupler.

I requested Headflux's REW mdat file for superposition. Anybody who uses that software may send his to me jkaudioreviews@gmail.com.

 

[durwood]

I have two suggestions on your Moondrop Kanas measurement anomaly.
1) Insertion depth too much. I noticed when I tested my HF3 I could severly depress that region but that might have been because of the triple flange
2) TIps, maybe the tip you are using is closing off the opening too much. I think I remember reading Crinacle used strictly foam tips for all measurements. I try to use the same wide bore small size from the T2 since it fits into my 8mm coupler tube easier. I don't ever see anyone else mention what tips they use to seal in the couplers.

I will measure my KP here in a bit and see if I can introduce the same depression using different insertion depths. I have lines marked on my clear vinyl tube that is roughly the the IEC standard volume that I use to line up the tip of the earphone to the UMM6 mic. I try to do what crinacle does and make my peak near 8khz.
http://www.aes.org/technical/documentDownloads.cfm?docID=177

 

[durwood]

As I change the distance from tip of the IEM to the mic, you can see what happens. The green colored measurement was the closest to the mic. Your measurement looked like your resonant peak was up near 15Khz, where I think using IEC standards should end up around 8khz, this might be hard to achieve depending on the coupler used? I have no experience with anything other than a piece of tubing though, it is just what I have read when someone said a specific coupler already puts it past the "reference plane". It's good to note too how insertion depth / volume of the ear canal between two people can drastically alter the listening experience. The couplers on the market are all trying to improve on the valid range of the measurement. I think the GRAS one is claimed to be accurate up to 13.5Khz .

 

[Otto Motor]

I have two suggestions on your Moondrop Kanas measurement anomaly.
1) Insertion depth too much. I noticed when I tested my HF3 I could severly depress that region but that might have been because of the triple flange
2) TIps, maybe the tip you are using is closing off the opening too much. I think I remember reading Crinacle used strictly foam tips for all measurements. I try to use the same wide bore small size from the T2 since it fits into my 8mm coupler tube easier. I don't ever see anyone else mention what tips they use to seal in the couplers.

I will measure my KP here in a bit and see if I can introduce the same depression using different insertion depths. I have lines marked on my clear vinyl tube that is roughly the the IEC standard volume that I use to line up the tip of the earphone to the UMM6 mic. I try to do what crinacle does and make my peak near 8khz.
http://www.aes.org/technical/documentDownloads.cfm?docID=177

Interesting. Thanks. Needs to be tested.

1) When I insert too much/deep, I lose bass, totally. Maybe the coupler is too short? But this should affect all our measurements. Not sure who defined the coupler's length, will have to find out. Our coupler:

• Inner tube: 10 mm long clear vinyl water pipe tubing, 5/16″ inside diameter, 7/16″ outside diameter
• Outer tube: 20 mm long PVC pipe, 7/16″ inside diameter, 1/2″ outside diameter
• Slide 5 mm of inner tube over end of Dayton IMM-6 mic (it helps to mark the tube at the correct position)
• Slide 5 mm of outer tube over end of inner tube.
• The internal volume of this ‘stepped’ coupler is 1.68 cc. ‘Medium’ tip sizes fit best.

We typically insert the tips until the ends of the skirts are flush with the end of the coupler. This results in variable nozzle insertion depths with different tip/nozzle combinations – and therefore different driver-to-mic distances and remaining internal coupler volumes. It is intended to mimic the effects of shallow- or deep-fitting IEM designs.

2) Bore width: hmmm...I always measure with the same pair, and often compare narrow-bores and wide-bores -- an example:
https://i.imgur.com/Hs0vbzl.jpg


I certainly can smoothen my upper midrange peak to a plateau by increasing the volume of the input signal...which results in clipping the peaks.

Don't forget, the main criticism of our measurements is a drop between 2 and 5 kHz by 3-5 dB, which is not as dramatic as it looks. If plotting all plateauing curves on top of each other, our 2-5 kHz area would sit in between the plateaus above and below. The present cherry picking should be extended all along the spectrum.

 

[Otto Motor]

As I change the distance from tip of the IEM to the mic, you can see what happens. The green colored measurement was the closest to the mic. Your measurement looked like your resonant peak was up near 15Khz, where I think using IEC standards should end up around 8khz, this might be hard to achieve depending on the coupler used? I have no experience with anything other than a piece of tubing though, it is just what I have read when someone said a specific coupler already puts it past the "reference plane". It's good to note too how insertion depth / volume of the ear canal between two people can drastically alter the listening experience. The couplers on the market are all trying to improve on the valid range of the measurement. I think the GRAS one is claimed to be accurate up to 13.5Khz .

I don't see any drama in there either. First, all of your graphs are closer to ours than to the plateau ones, all of them are forward inclined in the 2-5 kHz range. Second, the variations you show are totally normal. Third, you tell me which insertion depth is the right one? I have given the reasoning for our insertion depth above. Fourth, which of your graphs is the right one? Answer: all. Fifth: our ear is a totally different coupler alltogether, and each ear is different.

Sixth: I'd therefore not sweat it at all.

When you perform these measurements over and over again for different earphones, you get a much better feeling than just looking at them as a reader.

 

[CoiL]

Otto, my recommendation for Your review site - get better coupler and mic and get it properly calibrated. iMM6 is not "adequate" for proper review sites imo

But about that iMM-6 coupler - better lose that second pipe and do it with one PVC tube (sealed with silicone gel or other methods that are airtight). Already that PVC pipe edge You have there inside other pipe could give different result.

 

[Otto Motor]

Otto, my recommendation for Your review site - get better coupler and mic and get it properly calibrated. iMM6 is not "adequate" for proper review sites imo

But about that iMM-6 coupler - better lose that second pipe and do it with one PVC tube (sealed with silicone gel or other methods that are airtight). Already that PVC pipe edge You have there inside other pipe could give different result.

(1) Most "proper review sites" don't measure anything (and those who do frequently add compensations and stuff that is hard to follow). We offer both. Feel free to prefer those of our reviews without any data as more reliable .

(2) The setup is calibrated.

Whether the Dayton mic is good enough is another question. It is widely used and was used for a long time by Crinacle. It is great for comparisons between earphones, it is great for showing the result of modding steps, it is great for discovering channel imbalances. And it has done a good job in demonstrating the basic flavour of the earphones measured. And that's all we want.

It still has to be demonstrated inhowfar the other setups are "accurate". You can't just vote here which one works and which one doesn't. You also can't vote on 5 being bigger than 15, you have to demonstrate it. I have only seen doubt created by broad statements and belief-based opinions but no facts for anything. So, as a first step, superimpose all your "accurate" curves in a single diagram, then we talk.

 

[durwood]

That looks way too short, while I wish I had a way to relieve pressure from inserting I went with a basic 8mm I.D clear vinyl tube. That means the space between the IEM tip and mic end is about 2cm.

 

[Otto Motor]

That looks way too short, while I wish I had a way to relieve pressure from inserting I went with a basic 8mm I.D clear vinyl tube. That means the space between the IEM tip and mic end is about 2cm.

Will have to investigate. Our space between the mic end and the tip is 2 cm minus the tip length.

You may explain what the optimal distance is and why?

As it stands we have a variety of contrasting opinions from correction required by increasing distance to setup is not calibrated/mic is no good.

 

[CoiL]

Uh Oh... I could ask some compromising questions about Your calibration and why Your measurements differ etc. ...but I just don`t bother. Do what You want and how You want, not my to say.
I personally hope You get Your measurements more "credible", accurate and comparable to others, not just Your buddy.
But You could stay with Your own settings and start to create Your own "database" which can be used within Your site reviews. Latter is easier way.
Good luck with Your measuring gear and everything related to it

Btw, I would like to hear what hakuzen has to say about all this as he has spent some serious time for his evolving measuring gear.

 

[Otto Motor]

But You could stay with Your own settings and start to create Your own "database" which can be used within Your site reviews. Latter is easier way.

But that's exactly what we do -- and what we have claimed all along, in every single review of ours! "...These measurements should not be directly compared to other measurements except those done on the same device..."

Source: https://www.audioreviews.org/rig-setup/

And here it is, our internally consistent database: https://www.audioreviews.org/measurements/

Great, now we can stop beating the dead horse .

The distance between earphone and mic is one thing we will have to discuss internally. I am not the expert on that.

 

[darmanastartes]

Insertion depth was the first thing I thought of when this came up. Like @durwood showed, I've found that varying the insertion depth can dramatically change the midrange.
I agree with others that your insertion depth is way too short. I think it was discussed earlier in this thread that we should be shooting for an 8k resonance peak.
That said, I disagree with the idea that an iMM-6 is inadequate for serious reviewing. As you said, most reviewers don't have measurements at all.