Just listened to some Fostex T50RPs today... WOW!

[Taowolf51]

I'm thinking I want to add a bit more treble to these guys, but I don't want to change the bass. I've heard of a few things like the furniture puck, or the "raising earpads 6mm up" (which I didn't find instructions for). What mod should I do to increase the treble? I have the Sure 840 pads.

 

[Magick Man]

More treble? Try adding a little more cotton.

 

[Lurkumaural]

Not sure what the deal really is with those T50RP solder pads, but when I noticed I was applying a bunch of heat to the existing joint (that I had fluxed) and nothing was happening, I pulled away.  After a few minutes to cool down, I took an alcohol-soaked cotton swab to the solder joint.  Then I swabbed on some flux, and tried again.  Much better result; I was able to get in and out of there very quickly.
 
I don't understand soldering nearly half as much as some folks here do, and from my experience I can only speculate that I was removing some sort of coating before putting my novice DIY skills to use.  But I know that I wanted to be really quick on that solder joint, and I was.  Solder was 63/37 from Radio Shack that I've had for like 10 years.  Flux came from Steren, and they sell a lot of utter crap.  No magic, no aluminum, and not even a great pair of hands.
 
 

 

[wje]

Quote:

More treble? Try adding a little more cotton.

I remember asking you earlier if you had a reflex dot on yours and you said you didn't because your 'phones provided plenty of upper end.  Ironically, I skipped the reflex dot during the last re-assembly and fluffed up three cotton balls and the upper frequencies are just spot on.  I have no desire for additional treble at this point.  And, I'm a person who was a Grado fanboi, who loved the detail of a Grado headphone.
 
 
 

 

[BlackbeardBen]

Quote:

Color me naive, but when I enter in some guesstimates of what a cardboard resonator's dimensions are, I get frequencies back ranging from 6-10k.  Which is actually ideal to me since it's the 10k peak and 6-8k sibilance I'm interested in subduing, but I have a feeling I'm missing something critical with my guesses.  Example: slot width .2mm (x-acto slice), slat width 5mm (width of a cell), wall depth 3mm (depth of a cell), slat depth .5mm (thickness of the cardboard itself) = 8020Hz.
 

As I would suspect.
 
 
Quote:

But again, with this caculation, it seem like i can never absorb the most low frequency because the cup is too small, there isn't enough space to make "right" resonator to absorb 20, 30hz... But it's the most effective way to absorb low frequency, it's must be better than fiberglass, so i tried it and you know, it work.

 
That seems like a bit of a non-sequitor to me.  It can't work...  It does work.  The problem is it can be the most effective way to absorb bass bands, but it is not necessarily.  If it is tuned too high (as it may very well be), it's not going to make any effect on bass other than what the cardboard itself in there has.
 
Don't forget that the slat-type Helmholtz resonator is only one type - the traditional and fundamental cavity with neck design seems to be quite a bit more basic.
 
http://en.wikipedia.org/wiki/Helmholtz_resonator
 

 
So you can decrease the area of the neck to reduce the frequency you absorb - that's not impossible to do in a headphone cup.  The more difficult task would be designing an optimized cavity/neck shape.  I suspect a "squished flat" spherical Helmholtz resonator shape may work well.

 

[proid]

Quote:

As I would suspect.
 
 
 
That seems like a bit of a non-sequitor to me.  It can't work...  It does work.  The problem is it can be the most effective way to absorb bass bands, but it is not necessarily.  If it is tuned too high (as it may very well be), it's not going to make any effect on bass other than what the cardboard itself in there has.
 
Don't forget that the slat-type Helmholtz resonator is only one type - the traditional and fundamental cavity with neck design seems to be quite a bit more basic.
 
http://en.wikipedia.org/wiki/Helmholtz_resonator
 

 
So you can decrease the area of the neck to reduce the frequency you absorb - that's not impossible to do in a headphone cup.  The more difficult task would be designing an optimized cavity/neck shape.  I suspect a "squished flat" spherical Helmholtz resonator shape may work well.

I use stiff paper which the surface is flat and soft, compare to raw surface of cardboard to form another resonator and the effect is quite the same. Maybe it work more a diffuser than a resonator. Using the formula above, i can't think of a way to get small frequency, with the smallest A, max Vo and L that still fit the cup, i can only get 3,4khz.
 
Edit: Wondering if this will work:

 

[kalbee]

Proid, how does your resonator fare in terms of reverberation? Just wondering if you also encountered this issue; I know we didn't try same methods.
I implemented a 5mm depth 4x4cm resonant panel/variable frequency absorber made of tissue paper box, loaded with plasticine diffusers on top and loaded with loose cotton inside. It did wonderfully increase the bass response in my setup, but ironically I now have problems with the reverb time increased and instrument separation is pretty bad. With a very elementary iphone FR graph analyzer graph and stock mic (in other words: completely inaccurate) I am however getting a very flat curve on white noise even compared to previous tries.
Granted my setup doesn't have nearly as much foam loaded in cups and baffle.
 
Can't say much of what frequencies it should be targeting, I didn't do any calculations prior to working on it. Should be some ultrasound.

 

[proid]

Quote:

Proid, how does your resonator fare in terms of reverberation? Just wondering if you also encountered this issue; I know we didn't try same methods.
I implemented a 5mm depth 4x4cm resonant panel/variable frequency absorber made of tissue paper box, loaded with plasticine diffusers on top and loaded with loose cotton inside. It did wonderfully increase the bass response in my setup, but ironically I now have problems with the reverb time increased and instrument separation is pretty bad. With a very elementary iphone FR graph analyzer graph and stock mic (in other words: completely inaccurate) I am however getting a very flat curve on white noise even compared to previous tries.
Granted my setup doesn't have nearly as much foam loaded in cups and baffle.
 
Can't say much of what frequencies it should be targeting, I didn't do any calculations prior to working on it. Should be some ultrasound.

I'm glad that your method work. In my config, after using the resonator, i think beside improvement in bass, the rest of sound didn't change or i couldn't identify correctly. Can you post some picture 

?

 

[eltocliousus]

Do you guys ever wear your fostex in public? Might give them a try through a portable amp, worried ill feel a bit silly though.

 

[kingoftown1]

Quote:

Do you guys ever wear your fostex in public? Might give them a try through a portable amp, worried ill feel a bit silly though.

If anyone asks, just say you forgot they were on your head when you walked out of the studio

 

 

[eltocliousus]

Quote:

If anyone asks, just say you forgot they were on your head when you walked out of the studio

 

Haha, will do! I'm really hoping I'll catch the eye of a Head-Fi'er and he'll spark a conversation with me, chances are small though.

 

[hans030390]

Quote:

Do you guys ever wear your fostex in public? Might give them a try through a portable amp, worried ill feel a bit silly though.

Who cares whether or not people will think you look silly? Then again, a lot of students wear large headphones around campus here, so I don't feel out of place. I'm more worried about enjoying my music than wondering what people passing by think of my huge headphones. They're just jealous for all I care.

 

[wje]

Quote:

Do you guys ever wear your fostex in public? Might give them a try through a portable amp, worried ill feel a bit silly though.

Is sitting at my desk in an office environment considered public?  I believe so.  In that case, I think when I was sporting my various pairs of modified Grados with exotic wooden cups, I'd strike up more conversations than I would with my Fostex 'phones.  For some reason, people were just attracted to the wood.
 
 

 

[Taowolf51]

The Fostex's aren't really big enough for you to look that silly. They more look like a cheap as hell pair of headphones (which is great for me since my only other option is the Denons, which scream "steal me", also I live in west Philly. )
 
Also, thanks for the advice Magick, I put a bunch more in (I don't think I was using nearly enough), and it brought out the highs nicely.
They're still dark, but only slightly, and that slight darkness makes them very comfortable to listen to.
These are becoming a great can for metal. It doesn't quite have the bass slam of my Ultrasones (what I'm trying to replace with the T50's), but they're mids and detail are nicer.

 

[wje]

Quote:

... west Philly. ) ...
 

Ah, near the Sunoco refinery?  Near the Schuykill Expressway?  Near the Veteran's Hospital?  Yeah, I've been through there in the day light.  If I had to do it at night, I think I'd pass on the offer.