[wualta]

Or lay in a supply of silica gel packets.

 

[kalbee]

Quote:

 
At that point you might as well start crafting cups out of aluminum. Either way, still not a great solution unless it's cold outside, in which case it might just have the opposite effect and make your ears too cold. 
 
The best solution still remains the simplest. Air out your ears for a few seconds every couple songs.

Sure isn't...
Unless for Halloween. Or some sort of costume show.
 
Don't silica gel packets heat up with moisture?

 

[wualta]

Quote:

Originally Posted by kalbee /img/forum/go_quote.gif
 
Don't silica gel packets heat up with moisture?

Those headphones couldn't have caught fire in the rain and barbecued that kid's head! I wasn't there! You can't prove anything!
 
Seriously though, since it's a mechanical process (adsorption) going on and not an exothermic chemical reaction, no, they won't. 

 

[fe2cruz]

This is some great advice thanks everyone. I will ditch the aluminum and try some listening sessions with silica
packets. I need to get more for my camera lenses anyway. Its been a humid summer. I tried other fabrics but
the bass just always sounded best with the leather/pleather materials. Maybe one day I can find some
lambskin or soft vegan leather to play with. 
 
Have any of you tried Great Stuff Spray Foam?
 
http://www.homedepot.com/buy/building-materials/foam/great-stuff-16-oz-gaps-and-cracks-insulating-foam-sealant-162848.html#.UGENGHn3tEk
 
What are the sonic properties of this foam? Would it isolate and trap sound like putty? Is it dense enough?
I like how its really light and strudy.
I wouldn't spray it in the can as its a mess to deal with when wet. I was thinking of spraying it into some balls to
dry and then dremmel shaving and shaping it it fit my t20v2 cups. Then I could drill bass ports into it like a
thunderpants or Koda can. Sort of like ghetto manual 3D printing. I'd line the ports if needed with some film.
 
Right now they sound great with plumbers putty but they are super heavy 550g. Its weight is balanced on my 
head evenly with no pressure issues like a Pioneer Monitor 10, but really heavy to handle off your head with
one hand. 

 

[Dyaems]

hey guys, any idea how thick or thin is the hp-1 driver? thanks

 

[vid]

A few posts ago I did a listening comparison between damping the HP-50S via physical means vs. damping it via EQ. In the shell of a nut, I first modded the phones via stuffing felts and so on into the cups, measured that response, took out the mods and put back the standard foam disc, measured that, then EQd until the response measured as identical to the modded response as possible.
 
Here are CSD plots for eq/non-eq. First is without, second is with.


 
The freq graphs for eq and non-eq, again. I modified the EQ slightly from last time to make it as close to the modded response as possible.

 
Basically, there doesn't seem to be a massive difference in the decay rates. Last time, I thought the EQd version sounded a bit harsher, and it does seem to develop a small ridge right at 5 kHz - whether that affects anything is a guess that one can make either way.
 
The felt mod I used overdamps slightly in addition to creating a nasty 3 kHz peak. Might try to bring that damping down a bit - my ears seem to like brightness less than they used to.

 

[wualta]

Quote:

hey guys, any idea how thick or thin is the hp-1 driver? thanks

Roughly 7mm. If you need it more exact than that, let me know.

 

[vid]

About the Unipolar 2000(!!). Stock, they measure badly on CSD - I count 15-18 sharp ridges past 3 kHz. Something's wrong with that driver in general - both sides measure equally unwell. I'll try some mods on them later in the day and take better measurements that can be shared.

 

[JadeEast]

Great to have some charts to look at. Anyone have an idea as to the cause of the 3k peak and ridge? 

 

[Dyaems]

Quote:

Roughly 7mm. If you need it more exact than that, let me know.

Thanks. Thats all I need to know, but the exact size would be fine as well.

 

[vid]

Graphs for the Unipolar 2000.
 
Stock CSD:

 
With the tape mod (i.e. taping up the side holes - suggested by MDR30 and some man on a German forum):

 
Stock + the EQ I'm currently using:

 
Frequency graphs for all three; blue is EQ, black is stock and grey is tape:

 
All graphs are of raw data. They were aligned at 1 kHz.
 
Anyways, the Unipolar 2000 has trouble in the upper area, quite clearly. Not sure why. The sound unmodded, as I've mentioned earlier, is mainly about a piercing treble that sounds very unnatural. With the tape mod, there's more bass but the soundstage is odd (not a surprise - the open cups are partly converted into closed ones). With the EQ, the 3 kHz brightness is done away with and the 5-7 kHz drop reduced - the sound is good but only when higher notes aren't being played; the treble still sounds a bit razor-y (in a bad way). I also tried measuring without pads to see if they were screwing things up, but no, they weren't.
 
Not sure what I'll do with these. I've noticed that taping up a few holes at the very top of the back of the cups (not the sides) seems to cut down on some of the treble sharpness, but I've not measured that yet. That could be done next. Reducing the ~8 and ~12 kHz peaks could be something to aim for. The soundstage is good and things below 3 kHz aren't to blame, so it's worth a look to see if things can't be improved.

 

[vid]

Quote:

Great to have some charts to look at. Anyone have an idea as to the cause of the 3k peak and ridge? 

 
If you mean on the HP-50S graphs I posted - the large peak is mainly an 'artifact' of them being raw measurements. It's the ~3 kHz ear canal resonance that gets smoothed out (to some degree, but not totally) when HRTF compensation is applied. Raw graphs emphasize this peak, and thus on a CSD graph with raw data any ringing in that area is also emphasized (but not created out of nothing, to my knowledge).

 

[JadeEast]

Thanks vid. I should probably learn more about HRTF vs raw data. 

 

[nick n]

nice to see some graphs, one of these days I'll get the test kit here rolling.
 
Revisited the Grundig 211-A again about 10 times tonight ( edited out the previous junk I wrote )

I need to take a break from all this. I'll try duplicating the Koss Dead Rebel damping if not then out under the next passing bus they go.

 

[vid]

The Unipolar are the strangest headphone I've tried to measure. When measured with an artificial ear, there's no 3 kHz mountain in the raw graph at all. And that mountain should always be there - see Tyll's raw graphs, any of them. Usually not having it would mean the upper mids are very recessed - yet I can't hear that on the Unipolar in a sine sweep. Relatively flat throughout the range with smooth rolling up and down (quite unlike the measurements for the most part). Maybe the huge size of the driver has to do with the way it measures?
 
Also, the amount of bass measured changes depending on volume. The more volume, the less bass is measured. This might be related to the amp or transformer box as well, but I've no idea if and how.
 
I did find by looking at the CSD graphs that a ridge which shows up at 10.8 kHz would probably be the worst offender. Considering its location, it seems to be riding on an ear canal resonance. Sure enough, when I measured with a pinna (which elongates the ear canal a bit when attached to the measuring setup), the peak shifted downwards in accordance with the 3 kHz resonance peak, as you'd expect from an ear canal resonance. I thus created a sharp EQ dip (BW of 0.05 on Electri-Q) that, when measured, got rid of the ridge. Then I put the phones on my head and listened on a sine sweep where that ~11 kHz resonance might be through my ears. Found it at about 9.8 kHz, put the EQ dip in there and quite a bit of harshness was gone. Also EQd down by about 1.5 dB the area between 1.5 and 2.5 kHz since I can hear a small hump there; and reduced energy around 7 kHz by 2 dB. The sound is decent like this (or great if you ignore anything above the upper mids).