Headphone Measurements Using Brüel & Kjær 5128 HATS

[amirm]

Just found my Etymotic ER4SR. Alas, all I have are foam tips and they simply don't want to fit inside the artificial ear. Variation in bass is massive with slight movement:

Looking at other measurements, they either don't show the 6 kHz bump or show it ever so slightly. I dialed in a -3 dB down filter at that frequency and it seems to work well to tame some brightness and harshness.

So difference so far in a few clips is quite significant.

Here are the distortion measurements:

And as a percentage of the output:

I had forgotten how nice they sound and how inefficient they are!

Then again I had also forgotten how they feel like you have an implant in how far you have to shove them in your ear!

 

[Gomjab]

I own both the Etymotic ER4SR as well as ER4XR and that is my experience getting them properly sealed in my own ears. And I have the advantage of a closed loop feedback system to help position them! The bass sounds fine when you get the good seal but otherwise sounds like crap.

 

[amirm]

So maybe it is a merit that this HATS shows issues like this.

 

[Mad_Economist]

Sealing earphones will pretty much inevitably behave this way - without the pressure chamber between the diaphragm and the eardrum, it's simply too tall of an order for such minute drivers to produce low frequencies at meaningful SPL.

Might I suggest trying a larger size of eartip? It seems like all your IEM measurements are quite leaky - moreso even than Sam Vafeai's.

 

[amirm]

Might I suggest trying a larger size of eartip?

As I mentioned, I only have the foam ones I use. Don't know where the rest are. If we get into this, I guess I have to stock up on various tips.

 

[Mad_Economist]

As I mentioned, I only have the foam ones I use. Don't know where the rest are. If we get into this, I guess I have to stock up on various tips.

Makes sense. FWIW, while I know that I'm sounding like a Comply shill - and cheaper alternatives definitely exist - I've generally found that their generic eartips provided consistent coupling with my 4128's canals.

 

[Gomjab]

If I used my IEMs more I’d go to an audiologist and get custom made tips for mine. I did find that one of the included silicon tips worked best for me but I still needed to shove them practically to my brain to get best seal.

I think the advise you got earlier about taking some real time measurements while placing headphones would be even more relevant to getting the IEM to get a good seal.

I am enjoying following along your saga of trying out the B&K unit.

 

[Francis Vaughan]

ANC IEMs like the AirPods Pro feature a microphone directed towards the ear canal. With continuous improvements to mic quality and real-time DSPs, would it theoretically be possible with this in-ear format to automatically reach a FR target within 1-2 db across the whole audible FR range, including elimination of the ear canal resonance, or would there still remain "laws of physics" limitations that would require a different approach to overcome that problem ?

With over-ear headphones the pinna poses a different challenge, right ? Could real-time analysis of the 3D shape of everyone's ears, maybe with a technology akin to Apple's Face ID, associated with real-time 3D calculation of the user's pinae effect on sound, theoretically be a solution to that problem ? Or would it be possible to already reach decent results with a multi-mic system inside the cup (I believe that AKG uses two mics for its one-time - not real-time - TrueTone evaluation) ?

A bit late replying so some of this has already been overtaken by reference to the JBL gaming headset. But in principle there is no reason it would not be possible to compensate for just about everything. The target is the eardrum and given it is smaller than the shortest wavelengths by a significant margin most if not all of the problems one gets with correction shouldn’t manifest themselves. The problem with the pinna inside a headphone is of course different to how it affects sound when listening normally. Inside the headphone it perturbs the HF inside the volume of the headphone. So the messy HF we see may change depending upon the user. How much it does is another matter. Some headphones will be more affected than others. So long as it stays minimum phase, which it mostly should all can be managed. Dynamic changes as the phones move on the head might be a trifle harder. Modifying DSP parameters on the fly is an interesting challenge.

 

[JohnYang1997]

I lost my mind....

 

[Blumlein 88]

I typically do link these things, but it's A Statistical Model that Predicts Listeners' Preference Ratings of In-Ear Headphones, parts 1 and 2 that I'm referencing. Bear in mind, we're talking about a consistent clustering of preferences with response that, at most, can be individually modified by a small portion of the canal's length; essentially the worst-case scenario, from a standpoint that HRTF differences are the major timbral issue with headphones.


That was the methodology used in the paper @pozz is referencing - am I misunderstanding your contention, here? I was parsing your complaint to be that without knowing the correlation of a headphone's in situ response and the wearer's HRTF, we can't predict subjective response.

That was my complaint.

So I went and read the 2018 paper, #9919 since it was the most recent. Claims to match prediction r=.98 for IE phones and .85 for OE phones using a GRAS 45. So especially with the .98 what more do we need?

Of course I've read many discussions on how the Harman curve isn't quite right.

So looking at various measurement results which seem to be almost unique though with agreeing broad general trends what is the problem? Maybe one thing is the measurements going bonkers above 10 khz. Maybe response at and above10 khz plays very little of a role into how headphone preference goes. Maybe that was from the music chosen in the test of this paper.

 

[amirm]

I think the advise you got earlier about taking some real time measurements while placing headphones would be even more relevant to getting the IEM to get a good seal.

I know this. But Jude at head-fi had claimed that this was a much less issue with 5128. I don't know how he can say this.

As I have said a number of times, I am uneasy with the requirement to screw around for the perfect fit with the HATS when users don't do that.

 

[Doodski]

I know this. But Jude at head-fi had claimed that this was a much less issue with 5128. I don't know how he can say this.

As I have said a number of times, I am uneasy with the requirement to screw around for the perfect fit with the HATS when users don't do that.

It seems to work better with headphones that fit the best(Sennheiser et al) and the rest are all rubbish according to the test results.

 

[Mad_Economist]

That was my complaint.

So I went and read the 2018 paper, #9919 since it was the most recent. Claims to match prediction r=.98 for IE phones and .85 for OE phones using a GRAS 45. So especially with the .98 what more do we need?

Of course I've read many discussions on how the Harman curve isn't quite right.

Well, good to hear that I wasn't misunderstanding you.

As far as people finding the Harman target non-ideal, that's not surprising - Olive's research explicitly shows meaningful variation in listener preferences. I personally think that the "absolute ideal" target, even for a headphone which wasn't attempting out of head localization of stereo and etc etc would require a meaningful match to an individual's HRTF...but most headphones don't even fall within a reasonably short distance of the normal spread around the average in the population.

IMO it would be very hard to find the at-the-eardrum parameters that make it impossible to improve on a headphone's linear performance - maybe impossible - but we are so far away from that point that it's really not overly hard to say "this absolute mangling of the response is almost assuredly further from what sounds accurate to everyone than this one".

And, of course, what we hear isn't just what goes into our ears - a point raised repeatedly in the Harman research. When people can see and feel headphones, a lot of their perceptions change - moreso still when money's changed hands over them. And this, I must emphasize, is completely valid...but it doesn't relate to the ideal frequency response.

So looking at various measurement results which seem to be almost unique though with agreeing broad general trends what is the problem? Maybe one thing is the measurements going bonkers above 10 khz. Maybe response at and above10 khz plays very little of a role into how headphone preference goes. Maybe that was from the music chosen in the test of this paper.

Broadly, >10khz response is simply a very small band in perceptual terms. Even before accounting for the generally greater as a function of frequency effects of hearing loss, the top octave isn't very central to our music, and many recording and processing techniques neglect it. You obviously hear when it's brickwalled out at 10khz, and I think there's significance to level past 10khz, but the fine details are always going to be pretty obscure (and, of course, this applies as well to speakers as to headphones, human heads are quite directional in that band).

 

[Mad_Economist]

I know this. But Jude at head-fi had claimed that this was a much less issue with 5128. I don't know how he can say this.

As I have said a number of times, I am uneasy with the requirement to screw around for the perfect fit with the HATS when users don't do that.

I have to really emphasize here, this is where it's handy to compare to in situ mic measurements - I had a similar vibe early on in my time of using a HATS, but once I started putting mics in my concha and measuring low frequencies, it became pretty hard for me to believe that the extremes of HATS low frequency behavior were accurate to my case (or most other cases of people with nerve endings in their faces and the ability to hear). That's not to say that perfect coupling is accurate either, but in terms of correlating on-head and on-HATS low frequencies, I find that "aided" placement by a human operator comes closer.

 

[Nango]

Makes sense. FWIW, while I know that I'm sounding like a Comply shill - and cheaper alternatives definitely exist - I've generally found that their generic eartips provided consistent coupling with my 4128's canals.

Would be good to know where to source good tips silicone or whatever made of, and cheap!!! Never ever I will pay $18 plus shipping for two tiniest pieces of rubber, no way!!!

 

[outerspace]

Has anyone here tried the Smyth Realizer? You go through a calibration cycle for your ears with a set of headphones and your speakers in your preferred listening position. The result (with head tracking) is hearing your speakers but through your headphones and the effect was dramatic. Switching cal files with another person destroyed the effect.

There is a free project called impulcifer. Without head tracking, but can give very good result in just one optimal position.

 

[YSC]

I am longing to see how good sealing ER4SR measured, I always suppose they will have a linear bass response as in neutral

 

[Chocomel]

sorry, I still don't get it.

let's simplify and say our ears just add a 10dB boost to 10k. a flat sounding headphone would therefore have a 10dB dip at 10k. meassuring that headphone with a perfect replica of our ears should then result in a flat curve, because it would also boost 10k with 10dB

Yes it would result in a flat raw Measurement but it wouldn't sound flat. Your hearing is expecting the 10dB boost from your ear so, if that boost is absence it'll sound like a dip.

 

[Chocomel]

I am longing to see how good sealing ER4SR measured, I always suppose they will have a linear bass response as in neutral

Crinacle's Measurements. No compensation applied.

 

[YSC]

right, and may I ask is this system have a soft ear canal? if this is the case does it mean even custom IEM can be forced inside and make a seal to measure?