Master Complaint Thread About Headphone Measurements

[amirm]

Could you add pass at a more reasonable volume level 70dB or so...94-114 dB seem like ear splitting levels, would a headphone designer be using this high of an SPL to judge the performance...these levels are "worst case", but certainly don't represent the volumes I would be using....
Thank you.

This was addressed earlier at length. Briefly, at 70 dB you are below threshold of hearing in sub-bass so that would make no sense. And at any rate, lower levels cause noise pollution in the measurements. As I have noted before, I have listened to music at 94 dBSPL and it is not at all ear splitting. In addition, equalization boosts levels very often in bass region so headphone needs to be able produce those levels properly.

 

[monkeyboy]

I re-reviewed the thread and found where the measurement issue was discussed...sorry for the re-post...one follow up question....when driven at lighter loads, does the frequency response change much, I assume the distortion is much lower...

 

[Darth Bubba]

Not related to any thread so far as I can tell, but your (Amirm) recommended headphone list without EQ is much shorter than your recommended headphones with EQ. Are we then frightfully restricted in our choices when we're using dedicated DACs and headphone amps and not running the music through a computer?

 

[Robbo99999]

Not related to any thread so far as I can tell, but your (Amirm) recommended headphone list without EQ is much shorter than your recommended headphones with EQ. Are we then frightfully restricted in our choices when we're using dedicated DACs and headphone amps and not running the music through a computer?

You're always gonna be more restricted about which headphone you can choose if you're not gonna be EQ'ing them. In my experience of headphone listening and viewing measurements out there, if you're not gonna EQ your headphones then get the AKG K371 as a closed back example, or get the Sennheiser HD600 as an open backed headphone. I've got the HD600 and it's really pleasant without EQ, I haven't listened to the K371 but it's a closed back that tracks the Harman Curve closely (likewise the HD600).

 

[amirm]

I re-reviewed the thread and found where the measurement issue was discussed...sorry for the re-post...one follow up question....when driven at lighter loads, does the frequency response change much, I assume the distortion is much lower...

Frequency response does not change.

 

[solderdude]

With some headphones it does change the FR (but slightly) due to non linear behavior (high 3rd harm distortion is an indicator).
As swings get larger for lower frequencies bass response is compromised.
I can't measure beyond 105dB SPL but here is the, not really cheap, SRH1540.

Most headphones do not exhibit this behavior yet below 100dB but might well at 115dB.
All traces are overlaid to 1kHz so the red trace is 97dB trace lowered -7dB. The purple trace is at 90dB SPL. Dark blue = 80dB trace lifted 10dB and teal trace = 70dB lifted +20dB. So this particular headphone lowers bass response somewhat (2dB/div) above 80dB in the bass.

Not all headphones do this but with Shure it seems to be be re thing, below SRH-1840

Below the $20.- Superlux HD681 (but modified)

The planar Edition XX does not change its FR at all.

The 50Hz and multiples wiggles are hum... ignore.

nor does the K371:

@pma did measure non linearity with the HD598

 

[NTK]

Not related to any thread so far as I can tell, but your (Amirm) recommended headphone list without EQ is much shorter than your recommended headphones with EQ. Are we then frightfully restricted in our choices when we're using dedicated DACs and headphone amps and not running the music through a computer?

The other option is to use passive headphone eq filters. Here is some excellent resources courtesy of @solderdude.
https://diyaudioheaven.wordpress.com/headphones/passive-filters/

 

[Darth Bubba]

The other option is to use passive headphone eq filters. Here is some excellent resources courtesy of @solderdude.
https://diyaudioheaven.wordpress.com/headphones/passive-filters/

Yeah, I'd wondered if this approach was "the last resort." I'm glad someone had already established this option path.

Thanks for the link.

 

[Deleted member 16543]

Are the KB5010/5011 pinnae used in the measurements or something else?

 

[solderdude]

Amir uses KB5010

 

[Deleted member 16543]

Good to know. I think the b&k 5128 would have been even more accurate, but at 3 times the cost it probably didn't make too much sense.

How was the target response calculated?

 

[solderdude]

it's the Harman curve for the 45CA.

 

[Deleted member 16543]

I assume it's not the same curve depending on what types of sensing element solution is used, right?
Is there any literature you can quickly point me to that explains how Harman arrived at that curve, for a 45CA using the KB501x pinnae?
It looks to me like there's a second expected peak missing around 6-8 kHz in that target.

 

[solderdude]

The Harman target is 'averaged' so there is an error between 6kHz and 20kHz which is headphone + position dependent.
This is why the measured response will always be jagged even when it isn't.
On the other had the response from 200Hz to 5kHz will be fairly accurate.

It is just a measurement with a specific fixture and a specific microphone + specific pinna from a single headphone on a single position.
Only the guy measuring knows what he encountered during measurements and selects which to show.

A single measurement point guaranteed to differ from those of others. This is why Amir doesn't convolve the measurements for EQ (it really is the wrong thing to do) but uses simple EQ that adresses the points that need adressing and why it differs from others as well.

The Gras 45CA is an often used test fixture (not a HATS) and is well described.

 

[Deleted member 16543]

My understanding is that you can buy the 45CA with different configurations, which the KB501x is one example of.

I hope Harman used the same pinnae to come up with their target curve, as different configurations would yield different target curves.

I was wondering if there is any literature which goes into detail about how Harman arrived to their target curve, specifically for a 45CA with the KB501x pinnae option.

 

[solderdude]

There is.
Member @bobbooo will know where to find it.
I just 'paged' him he might pop up.

 

[tential]

Less priority on headphones that are discontinued.

 

[amirm]

I think the b&k 5128 would have been even more accurate, but at 3 times the cost it probably didn't make too much sense.

Where it is supposed to be more accurate is where there is most variation. So the extra accuracy is not usable. I evaluated it for a few months: https://www.audiosciencereview.com/...easurements-using-brüel-kjær-5128-hats.15352/

The biggest issue with it is that there is no research target curve for it. Without it, you are completely in the dark. So you get a response with ups and downs. Now what? It is like being lost in a jungle without a compass. With no reference you don't know which is north. This is why I did not purchase it even though the company was wonderful to work with and highly supportive.

I think 5128 is useful in research where you can build fixtures and such to have repeatability for the same headphone. For reviewing many headphones that is not practical and you are just stuck with all the negatives of the fixture and none of its pluses.

 

[scooter]

@amirm if any chance may I ask you to test Jlab Omni Headphones? These are BT over the ear headphones with wired passive application supported, I've purchased them at 70$ 3 years ago (can be found at 30$ now at eBay).
Since then I've purchased Beyerdynamic DT770 and HiFiman HE-4XX and sold them shortly after audition. I don't know, maybe I'm already used to my headphones but they sound really good for its price point. I'm driving them through SMSL M100 DAC and Monoprice Desktop Amplifier. When I use them wired and EQ-ed I find them very detailed in all frequency regions, that's why I'm interested how would they measure.
BT mode is also very good without EQ.
Thanks for your time in advance.

 

[amirm]

Sure, I will be on the look out for them.