Headphone Measurements Using Brüel & Kjær 5128 HATS

[amirm]

On that graph we can't see how loud the headphone is playing though.

You are although not in SPL. The x axis is the measured relative output voltage of the Microphone. So it translates directly to SPL.

 

[Jimbob54]

If one of the headphones had a sharp rise in IMD, basically similar to a amp clipping then yes could indicate such behavior. On that graph we can't see how loud the headphone is playing though.

No, but dont you know the power going into it? so you kinda do

EDIT- seen Amirs reply so I am both very wrong but kinda right

 

[Chocomel]

You are although not in SPL. The x axis is the measured relative output voltage of the Microphone. So it translates directly to SPL.

Yeah true, in this case i meant seeing the SPL so could what's happening at what volume level easily.

 

[Jimbob54]

Not necessarily. IMD - and any other measure of general nonlinearity - is some proxy here, but many headphones have a fairly sharp discontinuity in their linearity vs. output level at some point (where they begin to "compress"), the same as with speakers. Unlike with speakers, this point is typically at a higher level that is cause for concern even with cheaper models, but it's an interesting measure nonetheless.

Which is the point where I start looking at things flying over my head. But I would bet a fair slice of the contents of my wallet that the Ether CX would perform well in a test of that directly.

 

[Mad_Economist]

Which is the point where I start looking at things flying over my head. But I would bet a fair slice of the contents of my wallet that the Ether CX would perform well in a test of that directly.

if @Chocomel is willing to match you on that bet, perhaps @amirm can make one of you some money...

 

[Chocomel]

if @Chocomel is willing to match you on that bet, perhaps @amirm can make one of you some money...

If we set an lcd2 as the headphone to beat i would take that bet

 

[MarsianC#]

You could use some waterbased lube (ha ha) instead of spit/earwax

 

[Jimbob54]

If we set an lcd2 as the headphone to beat i would take that bet

I was rather hoping you'd opt for a pair of Beats as your champion. Or even better, a pair of AT M50x BT.

He has neither though- so Amir, crank up the Ethers until they bleed. For kicks

 

[Nango]

One issue I am finding with the pinnae on 5128 is its material characteristics. It is soft and flexible which is its claim to fame. But it also has high stiction with similar material such as the silicone tips of IEMs. They are like magnets and instantly stick to each other, making it harder to find the ear canal and push it in there. Hard pinnae don't have this issue. Real ear has a bit of this and the reason I like silicon tips but not as much as what I am seeing on 5128.

I guess the solution is to use foam tips.

But I also worry whether the pinnae is grabbing onto the pads of circumaural headphones. Hard to know how bad this issue is as the pinnae is occluded by the headphone pads.

Foam tends to absorb low freqs due to the porous texture!!

 

[Racheski]

Maybe measure the cheap TH-02 and see if you can EQ them to sound decent, just for lolz...I mean for science.

 

[zermak]

FWIW, on-ears may vary less than you'd think with good fit - the small pads limit the range of positioning to some extent, and anthropomorphic HATS' pinnae (e.g. modern pinnae for KEMAR, 4128, 5128, etc) are designed to deform in ways that mirror human ears.

Vis-a-vis in-ears, that's actually something of a point of controversy/interest regarding the 5128, it consistently shows different low-frequency behavior to conventional IEC711/60318-4 couplers - Sam Vafaei (formerly of RTings) is of the view that this constitutes a problem, whereas Jude Mansilla of Head-Fi regards it as a feature. I remain undecided for lack of thorough analysis.

I see the point on the on-ear, cause of the less area but there are some on-ears (like the cheap Sennheiser PX100 or the Koss Porta Pro and similar) which have low clamping force and kinda acts like nearfield (let me pass the term here).
I missed some data for the IEMs, I'll read the first post better but on a first look of your link can pint out on a different compensation curve on the RAW data itself(?).

It goes even further than your ears but also the shape of your head where some people might not be able to get a good seal and in turn get wildly different responses. For example the HD820 .

Yeah definitely. Plus add the factor of the usage and mechanical loss (I have a pair of K712 Pro in which the elastic string is worn out and I replaced it with another to have a proper clamping force).

One issue I am finding with the pinnae on 5128 is its material characteristics. It is soft and flexible which is its claim to fame. But it also has high stiction with similar material such as the silicone tips of IEMs. They are like magnets and instantly stick to each other, making it harder to find the ear canal and push it in there. Hard pinnae don't have this issue. Real ear has a bit of this and the reason I like silicon tips but not as much as what I am seeing on 5128.

I guess the solution is to use foam tips.

But I also worry whether the pinnae is grabbing onto the pads of circumaural headphones. Hard to know how bad this issue is as the pinnae is occluded by the headphone pads.

Foam tips is the way I guess and plus they are more comformtable (on my IEMs) and have better isolation and are more stable.

For tips that are a bit hard to push in, a pro trick is using a bit of spit.

Just dont tell B&K.

Ew. I wash the ones on mine every other day.

 

[bobbooo]

Foam tends to absorb low freqs due to the porous texture!!

You mean high frequencies?

 

[Nango]

Maybe all kind of.

 

[bobbooo]

Maybe all kind of.

Lows aren't likely to be notably affected. The biggest changes are at high frequencies, as Jude's measurements of the Westone W60 show:

 

[Mad_Economist]

I missed some data for the IEMs, I'll read the first post better but on a first look of your link can pint out on a different compensation curve on the RAW data itself(?).

The compensation curve doesn't vary in that band for anthropomorphic gear - the questions is what one shows us the behavior of IEMs in situ at low frequencies.

 

[Nango]

This chart does not show at the long end what I would call absorbing/diminishing, the courses totally change!!

Silicone tips look all equal to me more or less, but foams are very different within the class, some are stiffer, other are less firm.

 

[zermak]

The compensation curve doesn't vary in that band for anthropomorphic gear - the questions is what one shows us the behavior of IEMs in situ at low frequencies.

I meant some "problems" with the mics calibration.

 

[Mad_Economist]

I meant some "problems" with the mics calibration.

Unless they are physically broken, the WS2P (IEC60318-4)/WS3P (5128, memory serving) microphones in the ear simulators should be linear in frequency response. The differences between the couplers are significant because we want to know which one approximates the pressure at a human's eardrum.

 

[zermak]

Unless they are physically broken, the WS2P (IEC60318-4)/WS3P (5128, memory serving) microphones in the ear simulators should be linear in frequency response. The differences between the couplers are significant because we want to know which one approximates the pressure at a human's eardrum.

They should indeed but maybe something went wrong or it's Amir messing with the settings and so we have lower bass responses compared to other HATS when using IEMs (cause for what I see bass responses are close to other HATS).

 

[Mad_Economist]

They should indeed but maybe something went wrong or it's Amir messing with the settings and so we have lower bass responses compared to other HATS when using IEMs (cause for what I see bass responses are close to other HATS).

As said, interpretations vary here on the accuracy argument and exact causation, but whatever the case, it's not going to be a matter of a single linear compensation between the two - note the plots in the PDF I attached earlier, the low-frequency variation is unit specific because it reflects a difference in acoustic impedance. What's sort of troubling is that it's rather annoying to accurately measure eardrum SPL with IEMs, so getting a definitive answer on which coupler better approximates the human case is difficult.