Master Complaint Thread About Headphone Measurements

[LightninBoy]

I think the audiophile objection to Beats like bass has nothing to do with sub-bass and everything to do with mid and upper bass. A bass response like the one on the Beats Pro muddies up the bass and lower mids and just doesn't sound good. You'll note that it's nowhere near the Harman target.

Not the point I was trying to make, so let me restate without referencing Beats: I wonder if the general anemic bass of high end headphones have created a set of consumers who believe that is the correct response and anything more is marketing to a crowd who prefer unnaturally boosted bass.

 

[AudioJester]

Might have missed this, but can the new measuring rig measure IEMs?

 

[Feelas]

Not the point I was trying to make, so let me restate without referencing Beats: I wonder if the general anemic bass of high end headphones have created a set of consumers who believe that is the correct response and anything more is marketing to a crowd who prefer unnaturally boosted bass.

This is VERY possible, yet it can't be said that it's been done on purpose - if you're targeting referencin the general speaker curve (which varies wildly), the curve is usually low-shelved around the same region, thus it makes sense.

Yet after we're through with subwoofers being pretty much everywhere, there's no longer any excuse to be made on that.

 

[amirm]

Might have missed this, but can the new measuring rig measure IEMs?

Yes. Getting IEMs to fit properly though may take some doing. So I am not yet ready to do anything formal.

 

[pwjazz]

Not the point I was trying to make, so let me restate without referencing Beats: I wonder if the general anemic bass of high end headphones have created a set of consumers who believe that is the correct response and anything more is marketing to a crowd who prefer unnaturally boosted bass.

Perhaps, although I've seen popular audiophile reviewers advocating for bass shelf EQ for years.

I think more likely is that audiophiles tend to gravitate towards open back headphones and value the perception of "detail", which is easily lost if the bass elevation persists into too high frequencies, so they'd rather have something bass light and detailed than the opposite.

I think it must be challenging to tune open back headphones with a Harman bass shelf, as I can't think of any that manage to do it, and in my own experimentation with headphone design, I couldn't do it either.

 

[antdroid]

Perhaps, although I've seen popular audiophile reviewers advocating for bass shelf EQ for years.

I think more likely is that audiophiles tend to gravitate towards open back headphones and value the perception of "detail", which is easily lost if the bass elevation persists into too high frequencies, so they'd rather have something bass light and detailed than the opposite.

I think it must be challenging to tune open back headphones with a Harman bass shelf, as I can't think of any that manage to do it, and in my own experimentation with headphone design, I couldn't do it either.

I mentioned this previously, but the Fostex TH909 has subbass shelf for an open-back. Interestingly enough, the Foster Biodynamic drivers in the Fostex, Denon, and e-mu headphones increase in subbass when you take the wood cups off. It's quite nice to be honest. There are some of these drivers on aliexpress if you want to mess around.

 

[nerdoldnerdith]

I don't know anything about measuring headphones, but from what I've read those things are pretty hard to get right. As long as the measurements are consistent and repeatable that's a good place to start.

 

[Feelas]

Perhaps, although I've seen popular audiophile reviewers advocating for bass shelf EQ for years.

I think more likely is that audiophiles tend to gravitate towards open back headphones and value the perception of "detail", which is easily lost if the bass elevation persists into too high frequencies, so they'd rather have something bass light and detailed than the opposite.

Is it really the bass shelf itsel that kills the details, or is it the heightened THD of low-quality drivers paired with elevated bass making it even worse? I think that in low-distortion systems it's not really happening, despite the tuning.

 

[March Audio]

Couple more:

1. Perform listening test first to avoid being biased by measurements

This.

 

[tifune]

For instance bass drum and bass notes for instance ONLY reach peak levels when it is 'played'. At that time the amount of harmonics is overwhelming for a short period which masks distortion at those peaks.

Can you recommend some entry-level reading material on this effect?

 

[solderdude]

Just google 'bass notes' and 'bass drum hits' and you will find many tutorials for recording studios.
Of course there are electronically generated bass notes (as well as church organ) but these are not normal instruments.

 

[Helicopter]

Maybe we should make a bass killer track thread or a headphone test track thread to go with all the headphone reviews. There seems to be a theme developing with open-backed cans; although I don't mind the clips in real time as we comment on new reviews, it might be nice to have them in one place a year from now.

 

[Dreyfus]

In relation to the Harman target scoring ...

It gets smoothed to 12PPO.

Now that I think about it, I fear that a simple smoothing per octave model is not neccessarily accurate for a headphone FR scoring. The practical issue is that the Harman target does not make assumptions on the particular ear geometry. It was meant as a general guideline that deliberately leaves out high Q resonances caused by phase cancellations in the short-wavelength treble region. Those resonances are natural components of the individual human HRTF though and also present - at least exemplarily - when measuring with a 45CA that simulates a human pinna and ear canal.

Take the notch between 8 kHz and 10 kHz in the concha area as an example. This phenomenon can be seen on almost any headphone measurement @amirm has published so far. I am pretty sure that we will be see much more variance once we have gathered a larger group of different models by different manufacturers, though. The fact of the matter is that not every design excites ear resonances the same way. Also, placement can play a huge role for activating, deactivating and shifting such interactions.

Now, if we want to come up with a reliable scoring (as reliable as headphone measurements can be) then we would either need much more data with as many seating positions as possible and then take the average of those OR we would have to apply some filtering that ignores all the high Q peaks and notches and just leaves the general trend of the curve.

 

[DualTriode]

My complaint is that there is way too much variation on objectivity.

The Technologically Impressive LCD-4 Planar Magnetic Headphone Manufacturers Comments

My impression is that you intend to promote confusion and complain about lack of objectivity.

 

[Dreyfus]

My impression is that you intend to promote confusion and complain about lack of objectivity.

Feel free to contribute if you have something to say.

 

[TheTalbotHound]

Does Amir use a coupler/rig that allows for more accurate measurements above 10khz than the standard iec711?

 

[Dreyfus]

In theory, yes. His rig is equipped with the newer "high-res" generation of the 60318-4 ear simulator (RA0402) which is specified up to 20 kHz.
In practice however, there are a lot of issues with such resonators that do limit the area of certainty to around 8 kHz. Evertyhing above should be taken with a grain of salt.

 

[Kuba]

Would it be possible to to perform listening before and after the measurements? Maybe not always but once in a while. With headphones it shouldn't be as troublesome as with speakers. It may be interesting to compare your impressions influenced by measurements with those without bias.

 

[DualTriode]

Hello All,

Human ears do what they do. If your ears do what amirm’s ears do your ear lobes will flap about when you turn up the amplitude. Yes there are ear resonances and reflections that are reflected in what we hear with our own ears and measure with the GRAS 45CA test hammer. To some degree your ears hear different than the 45CA measures.

I am moving this thought to inside the box. No real ears or ear simulators are allowed.

When we measure speakers we move them into an anechoic chamber. There we test, measure, quantify and compare them. This is cold analytic speaker measurement. No ears or artificial ears are allowed or required.

The next step with speakers is to move them into a designed listening room and sit our heads and ears down in the sweet spot and say this is what good speakers sound like. We are also told that this is what a good set of headphones should also sound like.

What I am proposing is that we have missed or stepped over some increments in the headphone cold analytic measurement process. We have gone directly to ears and artificial ears. Oops to that.

Go to the GRAS site, you will find conversation and photographs of isolation chambers for the measurement and calibration of microphones. I am thinking that we should put headphones in similar isolation chambers with the same calibrated microphone to measure frequency response and what other variables you can think of.

For cold analytic measurement and comparison of headphone performance leave variable human ears and artificial ears out of it.

We have the technology to add any transfer function you need to plot a predicted on head Harman Curve compliance percentage.

Thanks DT

 

[Dreyfus]

Headphones are designed to interact with ears, not to work in free space or on flat plate rigs. Leaving that away will change the impedance of the system which will behave different for every headphone.

Flat plates are sometimes used for quality assurance because of their great consistency. They have very limited use for the practical design process and prediction of sound, though.

That is why we are here, talking about headphone measurement standards, ear shapes, canal resonances etc.
A simplified model does only deliver simplified data. That is the crux of the matter.