eindi
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Post by eindi on Feb 24, 2019 12:27:48 GMT
I got myself some DEkoni eaar pads for my Focal Clear and ended up measuring it again with the default ear pads. I noticed that its FR looked different than when I got it and a couple months after that. Of course ear pad wear is what you think in this case, but since I have the Clear Professional with spare pads, I could measure those and the result is basically the same:  I measure with a MiniDSP EARS. For bass and mids below 2 kHz, the measurements are very repeatable with little variation between measurements and reaction to seating. For treble, seating varies more, but that is not what I care about. You can see some lost sub bass and increased mid bass relative to each other. Old vs new pads barely makes a difference. I have multiple older measurements of the Clear ranging from May to August and they are all very similar. If I measure now, they are all different from back then. I have an HD800 that I also have old measurements of and could rule out that the measurement rig's FR changed. HD800 measures like it did 10 months ago. What is happening here? Legitimate case of burn in? Shitty quality control? |
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solderdude
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Post by solderdude on Feb 24, 2019 14:13:49 GMT
Consider temperature as an additional input.
It is still on my agenda to measure FR at different temperatures say from 0oC to 40oC.
I expect LF and HF to change due to materials being stiffer at colder temperatures.
Have never seen anyone measure it though.
I do have access to climate chambers so should be do-able.
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eindi
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Post by eindi on Feb 24, 2019 15:27:42 GMT
Good point. However my apartment is quite consistently warm and likely within 2 or 3 K of my older measurement. I could try cooling down the air and headphone more drastically for a rough test.
Edit: Rough test shows less bass at lower temperatures, but the difference is very small. For the change in bass to come from temperature, it must have been very hot last year, which it was not. SO I would say temperature is not the explanation here.
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solderdude
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Post by solderdude on Feb 24, 2019 18:46:52 GMT
Well the drivers aren't exactly like most other drivers out there.
Definitely other materials and geometries are used.
If not for temperature then perhaps from setting of materials ?
You didn't do any impedance tests showing resonances shifted over time ?
Resonance frequencies are known to change slightly over time.
The differnces are generally lower than 1dB. Measurement error or seal could easily do this.
Above 10kHz could be different seating or be caused by the cone material changing properties somewhat over time.
With the EARS positioning is very important.
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eindi
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Post by eindi on Feb 24, 2019 19:09:28 GMT
I did not test impedance. I don't think I have the means to do that. Certainly would have been interesting.
Below about 2 kHz the results are very repeatable as long as the ear pads have a seal. Above that, headphone positioning matters much more, but that area is not what bothers me. I have tried a lot and there is no way for me now to get the same result below 2 kHz that I consistently had a few months ago. I always get a result like shown in the graph, unless seal is bad and there is way less sub bass.
I have a saved result from August which is basically still the same as in May. So it looks like initially nothing changed and it all happened in the last few months.
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solderdude
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Post by solderdude on Feb 24, 2019 20:31:00 GMT
It is unlikely something in the driver in that case.
Otherwise it would have changed in the first few days of usage.
Did you measure other headphones as well in that time period you could measure again ?
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eindi
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Post by eindi on Feb 24, 2019 23:04:50 GMT
HD800 back from April and now:  Very close. |
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solderdude
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Post by solderdude on Feb 25, 2019 5:52:04 GMT
and the differences are on both channels ?
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eindi
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Post by eindi on Feb 25, 2019 8:19:34 GMT
I did not save a measurement of the right channel because it was like the left. Today the channel are still well matched. So I would say the right channel changed the same.
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solderdude
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Post by solderdude on Feb 25, 2019 19:25:11 GMT
The differences aren't big enough to really worry about, except maybe in the treble.
Changing to Dekoni pads will yield far bigger tonal differences though.
The clear I measured had substantial L-R differences so quality control may not be that great.
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eindi
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Post by eindi on Feb 25, 2019 20:29:35 GMT
I am not worried about it yet, but I will keep an eye an it. I bought the Clear for its good bass extension. It looks like I am in the process of losing that.
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