Topic: Preliminary Headphone Measurements - WIP, Your Thoughts? (Read 864 times)

Hands · « **Reply #30 on:** June 06, 2014, 12:45:17 PM »

Sure, I hope this helps! Mmmm, ear (this is the left one, BTW). Ignore the stray hairs...I'll be getting my hair cut soon.

Do you happen to have a link to the comparisons you did for Keith, or have them on hand in one way or another to share? I'd be very interested in the results and details of the comparison (such as was it done with/without compensation curves?). I also need to get my hands on an exact pair of a headphone others like Marv and UB have measured, and I do have that what-seems-to-be-awesome tour Grado on the way to me.

Solderdude · « **Reply #31 on:** June 06, 2014, 01:01:23 PM »

http://www.mediafire.com/view/?ac2017rapds7y0c

It isn't scientifically sound research but just a quick attempt to learn more about these methods.

As the mic wires aren't screened, do you also get a lot of hum ?

Simply make a recording with them in the ear and one with them just lying around and have a listen.
the measurements were all done on the same rig with the 16kHz already filtered but no other compensations (added LF compensation later on and re-measured some headphones)

Best way to get a baseline is by using headphones that measure well and consistantly.
Examples are HD580/600 and HD650 as IMO they do not very that much unless pads are worn.
Most measurements out there (from calibrated rigs) do match closely even when they are using different headphones.

The average of these plots should give you an idea how to calibrate your rig using a similar (or a few other) 'known' headphones.

Corrections should have to be small and broadband (except the well known peak of the WM61)
If you need sharp or much compensation something else is wrong.

For my rig I only needed the 16kHz adressed (slightly different for L and R mic and even had to replace one to get a closer resemblance) and LF compensation.
The LF comp. was very similar to that of dummy heads.
With this compensation I feel the meaurement is reasonably but not absolutely correct.

It does match what I hear and is highly repeatable.
Couldn't get that repeatability with mics in my ear.

Hands · « **Reply #32 on:** June 06, 2014, 02:44:13 PM »

Thanks a lot! I'll have to refer to that as I continue to work on my methods. I'm not sure about a hum. That's something I'll have to test out.

Haven't even the HD600/650 gone through variations?

Seems it's hard to find a HP that doesn't show some level of unit-to-unit variation. But, as mentioned, I'm glad I'm getting that Grado in soon. But I do agree that the HD600/650 seem to be one of the better headphones with which to help calibrate a measurement rig. I have an HD598...but it is modded...

So far, my compensation curve involves only mild and broad changes. Broad lift of the bass, broad reduction of upper treble, and a slight reduction of the area around 2-5KHz (shaped somewhat like a hump, basically). These are custom based on what I believe I hear subjectively vs raw measurements.

While my results thus far are not perfectly repeatable or consistent, I find it to be fair and, perhaps, even better than expected. No surprise, I have to take extra caution to make sure headphones that are picky about fit and seal measure consistently. It does look like the mic/tri-flange setup I use it a bit different than what you tried. As for how well my measurements match what I hear, it seems fairly close, but this is something I continue to evaluate.

OJneg · « **Reply #33 on:** June 06, 2014, 03:59:37 PM »

They've (HD600/650) gone through slight mechanical changes. But I suspect minute differences in your rig would be the dominating factor.

Hands · « **Reply #34 on:** June 06, 2014, 04:27:11 PM »

I would gladly pay shipping both ways if someone has one I could borrow. The HD650 is one of those headphones I know I should have bought forever ago, but I am often dumb like that. I have to go through my move and settle some financial matters before I should be buying more stuff. Funny or just stupid as it is, I say this as I recently bought an Alpha Dog. It makes all the sense!...

OJneg · « **Reply #35 on:** June 06, 2014, 05:06:16 PM »

Nice try hans! You ain't gettin' mine!

spoony · « **Reply #36 on:** June 06, 2014, 09:51:03 PM »

This is looking very good so far.

Here's an idea: Plots showing relative differences (A - B) caused by materials applied in front of drivers to attenuate treble. I know this could be of use to modders with sensitive ears for tuning HF peaks in specific spots. I would love to contribute myself but ATM I have no rig nor an interesting headphone collection to check for consistency with other measurements.

Hands · « **Reply #37 on:** June 07, 2014, 06:42:47 AM »

That's definitely something I would be interested in doing. If you have any particular headphones and/or materials in mind, I'm sure I can work something out.

As a small update, the new SPL meter I got seems to work much better. I was probably running my previous tests closer to 96dB at 1KHz, so now it should be much closer to 90dB. And now that my mic-in volume is adjusted for that, I should be able to get more accurate distortion readings.

spoony · « **Reply #38 on:** June 07, 2014, 03:40:35 PM »

Cool! I would expect the results to transfer somewhat unchanged between headphones. For starters we could have a figure for the infamous toilet paper mods, soft/hard single/multi layer creatology felts, foams... Variants blocking only the central portion of the driver grill to prevent over damping (BMD, foamie, electrical tape or micropore / transpore, ala 7506).

Personally I would benefit from seeing the effects of the creatology felts, micropore tape, and the BMD in both the T50RP and regular dynamics (CAL!?).

Thanks a lot!

Solderdude · « **Reply #39 on:** June 07, 2014, 04:31:58 PM »

The idea of a 'modding material effects database' is appealing.

In my experience, however, there isn't such a thing as a standard effect for a certain material.
At least I didn't find it to work this way.

I have several types and thickness's of felt, foam etc. but the results on headphone A differs from the same material used on headphone B.
It even differs from headphone A with pad B from headphone A with pad C.

I have toyed with a lot of headphones in different configurations and have not found an 'universal' effect a mod does.
Plenty of plots have been made over time and while you can see what effect something has on headphone A it isn't a guarantee the same mod will have a (very similar) effect on headphone B.

Another thing is repeatability of results, which also greatly varies from headphone to headphone.
When placing a material in front of a driver you also change the position of the headphone slightly.
This can only be done reliably when altering things on an electronic (signal) level.

Author Topic: Preliminary Headphone Measurements - WIP, Your Thoughts? (Read 864 times)

Hands

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Solderdude

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Hands

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OJneg

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Hands

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OJneg

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spoony

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Hands

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spoony

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Solderdude

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Author Topic: Preliminary Headphone Measurements - WIP, Your Thoughts? (Read 864 times)