ASR Headphone Testing and BK 5128 Hats Measurement System

[Mad_Economist]

Just to note, you don't need to spend $41k to get quite capable measurement equipment - Headphones.com and the independent reviewer Crinacle have recently acquired GRAS 43AG simulators for ~10k USD, and such systems are used by a number of different sites (Brent Butterworth at Soundstage, Keith Howard at HeadphoneTestLab and some UK print publications, Speakerphone/clarityfidelity, etc). Such a system would also have the convenience of de facto compatibility with any Harman data, as Olive has historically used GRAS pinnae.

 

[Mad_Economist]

Also a new HAT that comply with human acoustic impedance at any condition is much much better goal than extend frequency range. Did BK publish the data for the newly measured ear canal impedance? I think not.

It's been a while since I read their patent, but my understanding is that Bruel and Kjaer is specifically claiming to match the acoustic impedance of the ear to 20khz with the 5128. Certainly, that's what their marketing literature appears to claim.

 

[JohnYang1997]

It's been a while since I read their patent, but my understanding is that Bruel and Kjaer is specifically claiming to match the acoustic impedance of the ear to 20khz with the 5128. Certainly, that's what their marketing literature appears to claim.

Thanks. However the measurements for er4 was not ideal.

 

[Mad_Economist]

Thanks. However the measurements for er4 was not ideal.

Ideal in relation to what, though? Are we going back to the Zwislocki vs. 711 conflict, or are there in situ eardrum measurements of the ER4 I've forgotten?

 

[JohnYang1997]

Ideal in relation to what, though? Are we going back to the Zwislocki vs. 711 conflict, or are there in situ eardrum measurements of the ER4 I've forgotten?

It's very off from etymotic's published data in the highs. I know according to the paper the 711(60318-4) was a bit inaccurate. And 5128 is supposed to measure differently.

However the measurements don't at all comply to what I hear using sine sweep and matching to speakers. The highs just don't roll off like that. It stays flat and even goes up a bit. And yes I know I need to use a new target response to interpret but the peak doesn't affect diffuse field(or any open canal response )much.
If there's a direct comparison between old and new targets would be great.

Lastly the issue was not to extend the accurate range to 20khz but to make sure the impedance matches human canal at different canal volume. Only this way we can have both deep insertion and shallow insertion accurate. The original 711 was pretty accurate for deep inserting measurements, at least in my experience.

 

[Racheski]

Thanks. Alas it is not in stock on Amazon until August 27th which is too late. Any other options?

Tascam TH-02. It's $20, they have thousands of reviews on Amazon, and they got a pretty mediocre review on RTINGS.com . I have a pair of the TH-03 because they were bundled with a mic boom, and I find the treble to be really really fatiguing.
https://www.amazon.com/Tascam-TH-02...&keywords=tascam+th-03&qid=1596849223&sr=8-11

 

[JohnYang1997]

Just to note, you don't need to spend $41k to get quite capable measurement equipment - Headphones.com and the independent reviewer Crinacle have recently acquired GRAS 43AG simulators for ~10k USD, and such systems are used by a number of different sites (Brent Butterworth at Soundstage, Keith Howard at HeadphoneTestLab and some UK print publications, Speakerphone/clarityfidelity, etc). Such a system would also have the convenience of de facto compatibility with any Harman data, as Olive has historically used GRAS pinnae.

I would have a little step up and recommend 45ca-5. It's much better for measuring headphones.

 

[amirm]

Tascam TH-02. It's $20, they have thousands of reviews on Amazon, and they got a pretty mediocre review on RTINGS.com . I have a pair of the TH-03 because they were bundled with a mic boom, and I find the treble to be really really fatiguing.
https://www.amazon.com/Tascam-TH-02...&keywords=tascam+th-03&qid=1596849223&sr=8-11

Thanks. I ordered it.

 

[Mad_Economist]

It's very off from etymotic's published data in the highs.

It's been quite a while since I looked at what Ety publishes - are they still on the Zwislocki/ANSI couplers, or have they moved to 60318-4/711s?

However the measurements don't at all comply to what I hear using sine sweep and matching to speakers

This methodology cannot be used for the subjective evaluation of frequency response. Please see Theile 1986 as well as concurrent work by Spikofski, Zwicker - the term Theile likes is "SLD effect".

I would have a little step up and recommend 45ca-5. It's much better for measuring headphones.

You prefer it due to the removal of clamping force ambiguities?

Lastly the issue was not to extend the accurate range to 20khz but to make sure the impedance matches human canal at different canal volume. Only this way we can have both deep insertion and shallow insertion accurate. The original 711 was pretty accurate for deep inserting measurements, at least in my experience.

IEMs are an area of singular disinterest to me, so I haven't done much there, but from some dialogue with Oratory, he's done comparisons of in situ probe measurements of in-ear designs on a few ear simulators. I'll ask him if he can share his data here, assuming I recalled that correctly.

 

[amirm]

Just to note, you don't need to spend $41k to get quite capable measurement equipment - Headphones.com and the independent reviewer Crinacle have recently acquired GRAS 43AG simulators for ~10k USD, and such systems are used by a number of different sites (Brent Butterworth at Soundstage, Keith Howard at HeadphoneTestLab and some UK print publications, Speakerphone/clarityfidelity, etc). Such a system would also have the convenience of de facto compatibility with any Harman data, as Olive has historically used GRAS pinnae.

I am familiar with the alternatives. The question and that is why it is in the title, is whether the 5128 solves some problems that others do not. How much it costs is secondary to answering this. If it provides no value, then we need to demonstrate this next week when we get the eval unit.

 

[Mad_Economist]

Arguably the major feature from a cirum/supra-aural headphone standpoint of the 5128 would be its more flexible pinnae, and thus more consistent coupling - modern "anthropomorphic" GRAS pinnae (KB5000/5001) are the same in this regard.

The distinctive selling point of the 5128 are its higher resolution ear simulators - which really are extremely cool, IMO, the patents are well worth a read, B&K were very clever. Unfortunately, accuracy at very high frequencies may prove less useful than you'd think, as headphone response tends to vary substantially in this band even for a single pinnae, due to small positional variations being quite significant.

 

[amirm]

I don't think we can get much more value out of headphone measurements than we already have from existing sites.

Despite what is available out there, people ask me that we do that kind of testing. There is style and substance to what we do that is of value to people. Now whether it is worth significant investment will depend on whether we can do a better job of measuring.

 

[ehabheikal]

Hello everyone. I am out of my mind to be thinking about getting into headphone testing. But the itch exists and I am reminded of it often in private communication with people asking me why I am not testing headphones.

I had tabled the whole thing for many reasons, most of which is that I am not happy with state of the measurement systems out there for headphones.

There has been a development which may make the measurement situation better. It is the Brüel & Kjær 5128 HATS (head and torso simulator). Here are a couple of quick promotional video on it:

I like the flexibility of the artificial ear/pinna and better reliability and repeatability that this brings.

There are some big negatives however:

1. The 5128 extends the simulation limit of the older "711" standard substantially. But with it, it also makes the measurements non-standard so existing research may be difficult to apply to it.

2. The cost. Man, oh the cost. The full HATS has a retail cost of $41,000! There is a truncated one that is a bit cheaper (just the head and no torso). This is a stunning amount of money to spend to measure headphones.

I have asked BK to give me an evaluation unit to test. After all, I still don't know if this is a good solution or not. They have been kind enough to say Yes and the unit will arrive soon. I only have a few short days when I get it to test and then return it. Let me know what you think I should be measuring/doing with it.

Whatever you all do, don't mention a word about this to my wife! I honestly don't know how to go and tell her I want to spend $5,000 on this let alone nearly 10X that!

Anyway, any and all feedback is welcome including whether we should even bother doing this.

Being an audiophile is usually synonymous with being single lol

 

[JohnYang1997]

It's been quite a while since I looked at what Ety publishes - are they still on the Zwislocki/ANSI couplers, or have they moved to 60318-4/711s?


This methodology cannot be used for the subjective evaluation of frequency response. Please see Theile 1986 as well as concurrent work by Spikofski, Zwicker - the term Theile likes is "SLD effect".


You prefer it due to the removal of clamping force ambiguities?


IEMs are an area of singular disinterest to me, so I haven't done much there, but from some dialogue with Oratory, he's done comparisons of in situ probe measurements of in-ear designs on a few ear simulators. I'll ask him if he can share his data here, assuming I recalled that correctly.

1, Etymotic has adopted GRAS RA0045 for a very long time. So it's not swizlochi any more, yet I do have a such coupler very nice to look at.
2, I don't think it's anything wrong after reading. The objective frequency response can still be obtained. I wasn't talking about timbre/tone at all. Also it's very obvious that such roll off will never sound ok. So it's clear that the 5128 er4sr measurements have issues.
3, It's simply easier to use right? Just wear it on the fixture like on the head instead of pressing down on a plane. It's more natural and reduces errors caused by placing at the wrong place.
4, Considering in ears are the biggest issue here, it's very important. In ear prob method will be very difficult to control the volume to exact. In terms of Oratory, something must be wrong with his measurement setup....many iems and headphones just don't look right.

 

[ZenTraveler]

While I agree for doing testing on headphones I strongly feels it's pointless to have such expensive equipment for measurement. Reason being everyone hears differently, the most accurate reading machine will not be accurate for anyone. Something that give decent reading is enough as general guide how the headphone sound.

 

[JohnYang1997]

I just revisited oratory's database. I was probably seeing two extreme cases? The hd58x still looks very wrong to me. And I don't think there should be 5khz bump for hd600 and hd650(not as drastic). Er4sr's measurement now looks like the one on 5128. Not good looking on its own but the highs does look better on Harman target which I also complained to have too much roll off. The issue is still the same, many measurements have reduced high frequency response and extra bump/peak that shouldn't be there. But too my eyes, it does look better now. I don't know how probably due to 0db.kr switched to hires head and I don't go there anymore and Speakerphone rarely updates now also the retirement of Tyll. I kinda think oratory's measurements look ok now.

 

[Mad_Economist]

1, Etymotic has adopted GRAS RA0045 for a very long time. So it's not swizlochi any more, yet I do have a such coupler very nice to look at.
2, I don't think it's anything wrong after reading. The objective frequency response can still be obtained. I wasn't talking about timbre/tone at all. Also it's very obvious that such roll off will never sound ok. So it's clear that the 5128 er4sr measurements have issues.
3, It's simply easier to use right? Just wear it on the fixture like on the head instead of pressing down on a plane. It's more natural and reduces errors caused by placing at the wrong place.
4, Considering in ears are the biggest issue here, it's very important. In ear prob method will be very difficult to control the volume to exact. In terms of Oratory, something must be wrong with his measurement setup....many iems and headphones just don't look right.

1: They really are neat! Unfortunately, not very consistent it appears.
2: Note the section "Objections to Loudness Comparison Method" - essentially, perceived acoustic source impacts our mental inverse HRTF filtering; this, in turn, impacts subjective frequency response by the loudness comparison method, thus we can't use an external reference sound field. Further, I'm not getting what you mean regarding the 5128 ER4 measurements - the transfer function of the 5128 ear sim does obviously differ, reflected in the raw response, but this isn't necessarily wrong, since at high frequencies the old 711/60318-4s were not accurate in that band either.
3: Intuitively, I'd tend to agree, but the folks I've seen using them seem to have quite solid consistency with 43AGs - price being no object, I'd definitely take the 45CA, though, no question.

And I don't think there should be 5khz bump for hd600 and hd650(not as drastic)

His raw response resembles a measurement I made with a KEMAR of a HD600 some time ago (ignore the low frequencies, the noise environment was not stellar), as far as I can tell.

Speaking broadly, I'd consider Oratory's data set among the most "self-checking" out there, since he has access to a number of separate in-cal GRAS fixtures, and can cross check errant results. He's also simply a rather thorough and earnest fellow, I like him a lot, and he's generally quite willing to chat if you're polite.

 

[JohnYang1997]

1: They really are neat! Unfortunately, not very consistent it appears.
2: Note the section "Objections to Loudness Comparison Method" - essentially, perceived acoustic source impacts our mental inverse HRTF filtering; this, in turn, impacts subjective frequency response by the loudness comparison method, thus we can't use an external reference sound field. Further, I'm not getting what you mean regarding the 5128 ER4 measurements - the transfer function of the 5128 ear sim does obviously differ, reflected in the raw response, but this isn't necessarily wrong, since at high frequencies the old 711/60318-4s were not accurate in that band either.
3: Intuitively, I'd tend to agree, but the folks I've seen using them seem to have quite solid consistency with 43AGs - price being no object, I'd definitely take the 45CA, though, no question.



His raw response resembles a measurement I made with a KEMAR of a HD600 some time ago (ignore the low frequencies, the noise environment was not stellar), as far as I can tell.View attachment 77093

Speaking broadly, I'd consider Oratory's data set among the most "self-checking" out there, since he has access to a number of separate in-cal GRAS fixtures, and can cross check errant results. He's also simply a rather thorough and earnest fellow, I like him a lot, and he's generally quite willing to chat if you're polite.

I think what made Oratory's measurements look weird to me was the new anthropomorphic pinna. Original pinna would probably be better. Which was the corresponding one to the 4128c pinna? There were also two types of pinna. The stock has too small hole and new one has larger hole. That changed frequency response a lot.(i mean a lot).

 

[Mad_Economist]

I think what made Oratory's measurements look weird to me was the new anthropomorphic pinna. Original pinna would probably be better. Which was the corresponding one to the 4128c pinna? There were also two types of pinna. The stock has too small hole and new one has larger hole. That changed frequency response a lot.(i mean a lot).

FWIW, I'd argue (as would GRAS, and a number of others) than the anthropomorphic pinna presents a meaningful improvement, particularly with headphones which deform the pinna.

The GRAS equivalent to the B&K/ITU-T pinnae would be the KB0065/66 I believe. Speakerphone usually uses the IEC60268-7 (IIRC) compliant KB0060/61. For cross comparability purposes, the anthropomorphic pinna would be best, and given the eccentric deformation characteristics of the older pinnae, they are arguably meaningfully flawed for headphones with shallower pads.

 

[JohnYang1997]

FWIW, I'd argue (as would GRAS, and a number of others) than the anthropomorphic pinna presents a meaningful improvement, particularly with headphones which deform the pinna.

The GRAS equivalent to the B&K/ITU-T pinnae would be the KB0065/66 I believe. Speakerphone usually uses the IEC60268-7 (IIRC) compliant KB0060/61. For cross comparability purposes, the anthropomorphic pinna would be best, and given the eccentric deformation characteristics of the older pinnae, they are arguably meaningfully flawed for headphones with shallower pads.

Aren't all pinnas flexible? I thought the difference is the canal extension part?