Differences in soundstage and imaging in IEMs?

[DivineCurrent]

I've been experimenting with EQ on a few IEMs, in particular the Dunu Zen Pro and the Etymotic ER2SE. For both, I have done my best to match (or at least get close to) the response of my other open back headphones by using sine sweeps. For the most part I've achieved very good results, as for both IEMs the frequency response is now far more natural and open-back like, resembling both my HD650 and Focal Clear MG. However, both IEMs have a pretty large difference in perceived soundstage. The sense of scale on the Zen Pro is noticably bigger than the ER2SE, even when both have been tuned to a very close frequency response. It could be I have not perfectly matched the responses, however I am using the same tips for both and I am getting an excellent seal with both. Could it simply be that the smaller 6mm driver of the ER2SE does not displace as much air as the twice as large 13.5mm driver in the Zen Pro? Or is there a different explanation that involves digging more into the small differences in frequency response?

 

[theveterans]

Even if you match the FR of both IEMs precisely and volume matched them, the two IEMs have different internal chambers where sound can be shaped to have a large soundstage perception. Also I agree with you that better driver materials and air pressure control from the Dunu helps with better soundstage presentation since harmonics in the tone are more evenly produced compared to ER2SE

 

[MayaTlab]

using sine sweeps.

While I find sine sweeps, programmed or manual, immensely useful to help EQing headphones by ear, the only thing I can truly rely on them to tell me is that something is wrong, but not necessarily that something is right.

As far as I'm concerned, when the slope / magnitude of the deviations from ideal is below a certain point, I can't rely on sweeps to EQ two headphones to a similar curve.

That's something that I can actually verify with in-ear mics, for larger over-ears.

It could be I have not perfectly matched the responses

As long as it can't be verified in situ that FR indeed matches for most of the spectrum, that's always going to be the low hanging fruit.

For IEMs it's a particularly vexing problem given that in-ear measurements are a lot harder to perform than for larger over-ears (where it's already difficult enough).

The only smaller headphones I'm quite confident to measure with in-situ methods, so far, are my AirPods 3 below 800-1kHz (essentially because of the combination of their very leakage tolerant design and feedback mechanism).

 

[redrol]

Just to mention this, I helped tune the HBB Olina. What I was focused on was natural timbre and tonality AND ultra good 3D and wideness.

 

[DivineCurrent]

While I find sine sweeps, programmed or manual, immensely useful to help EQing headphones by ear, the only thing I can truly rely on them to tell me is that something is wrong, but not necessarily that something is right.

As far as I'm concerned, when the slope / magnitude of the deviations from ideal is below a certain point, I can't rely on sweeps to EQ two headphones to a similar curve.

That's something that I can actually verify with in-ear mics, for larger over-ears.



As long as it can't be verified in situ that FR indeed matches for most of the spectrum, that's always going to be the low hanging fruit.

For IEMs it's a particularly vexing problem given that in-ear measurements are a lot harder to perform than for larger over-ears (where it's already difficult enough).

I can confirm it is definitely easier to get the FR curve consistently with over ear headphones. I have in ear mics that I use to make my own measurements, and it's pretty easy to match one headphone to another just by using EQ filters in REW.

I tried again with the ER2SE, and it turns out I was not getting as good a seal as I thought with the Sony tips I was using. I switched to Spinfit tips, and not only is the seal better, but I can hear the sub bass extend all the way to 20 Hz. Now the soundstage seems much closer to the Zen Pro, maybe just a little smaller. I bet the tip change not only helped the bass, but the treble as well. These tips are also smaller and can go deeper in my ear, so insertion depth is something to be considered too. I'll have to do more experimenting, but from this I can say eartips make a bigger difference than I thought.

 

[theveterans]

I can confirm it is definitely easier to get the FR curve consistently with over ear headphones. I have in ear mics that I use to make my own measurements, and it's pretty easy to match one headphone to another just by using EQ filters in REW.

I tried again with the ER2SE, and it turns out I was not getting as good a seal as I thought with the Sony tips I was using. I switched to Spinfit tips, and not only is the seal better, but I can hear the sub bass extend all the way to 20 Hz. Now the soundstage seems much closer to the Zen Pro, maybe just a little smaller. I bet the tip change not only helped the bass, but the treble as well. These tips are also smaller and can go deeper in my ear, so insertion depth is something to be considered too. I'll have to do more experimenting, but from this I can say eartips make a bigger difference than I thought.

Definitely with the tips on any IEMs even that ludicrously priced Oriolus Traillii. Switching from the stock silicone tips to another silicone with less ID bore size resulted in collapsed soundstage and loss of EST drivers "air presence" that IEM is known for