[DaBomb77766]

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yes i know. it's for mass vibrations. i just personally feel acoustic absorption is more effective when it comes speaker and headphone enclosures if your looking to completely eliminate enclosure resonance.

I agree, mass loading hardly did a thing for me.

 

[Taowolf51]

Kind of a strange thought, but it has me worried.
I am going on a trip soon, and I wanted to bring my Fostex's. I did the clay mod, so I've got a bunch of clay in them. If they go through the xray with them, would the clay raise some suspicions?

 

[BmWr75]

I doubt it.

 

[headphonatic]

Forget this, move one

V​

 

[wdahm519]

Quote:

I agree, mass loading hardly did a thing for me.

We used the plasticine for medium mass loading because of the resonance issues on the baffle.  Its pretty important.

 

[kalbee]

Quote:

Kind of a strange thought, but it has me worried.
I am going on a trip soon, and I wanted to bring my Fostex's. I did the clay mod, so I've got a bunch of clay in them. If they go through the xray with them, would the clay raise some suspicions?

Doubt it lol. If they have doubts, let them have a listen (as long as you're not late for boarding).
 

 

[proid]

Quote:

if fiberglass was only good for mid and high frequencies then they wouldn't be used for bass traps. it can be used for headphones as well but you have to figure out the proper measurements yourself and experiment. combine it with other material like polyfill/fiberfill and you have the whole spectrum covered for complete absorption. that's just the back enclosure behind the driver though. people forget about the front a lot and never take in mind that could make a big difference how the sound waves are fired into the ear cause planers of course are bipolar/dipole and fire in both directions evenly. like the shure 840 pads that's used a lot. you simply can stuff things in there to experiment. i find using the 240 foam disc(the thick foam disc in the 240 studio model) to work great cause it will help bring both the treble and bass up. you can also use things like cut outs of speaker cloths,cotton pads,very thin layers of silk,coffee filters,ect in different types of combination in different layering and so forth. it will help slow down and prevent resonance around the ear and help deliver a clean, smooth response. there is so many different ways to achieve multiple things. the possibilities are endless.

 
Yes, fiberglass is used in bass trap but you must know how it work. To absorb low frequency, you must make the panel very thick and mount it away from the wall or else it will absorb mid and high frequency very good but poor with low frequency, take a look: http://www.bobgolds.com/AbsorptionCoefficients.htm
 
 

 

[satwilson]

Quote:

We used the plasticine for medium mass loading because of the resonance issues on the baffle.  Its pretty important.

Agreed, you must control the resonance of the baffle...and then the enclosure/cup, BOTH are important. To simply deal with enclosure issues with cotton balls, fiberglass, etc, is only part of the solution. For me, plasticine loading the baffle, along with cup damping gave me the best result. This has nothing to do with "play doh" for those who don't understand "plasticine damped baffle". Fiberglass, cotton. mineral wool, whatever, doesn't address the problem with the resonant/flexible baffle.
 
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I agree, mass loading hardly did a thing for me.

 

 

[RexAeterna]

Yes, fiberglass is used in bass trap but you must know how it work. To absorb low frequency, you must make the panel very thick and mount it away from the wall or else it will absorb mid and high frequency very good but poor with low frequency, take a look: http://www.bobgolds.com/AbsorptionCoefficients.htm

 

i know that obviously. that's why you use it in combination with something like fiberfill/polyfill. polyfill will make the driver believe it's in a larger enclosure basically making the overall distance from the driver to the fiberglass more expansive. thing is too thickness doesn't play the same rule with headphone enclosures cause the driver is much smaller compared to something like a 12'' woofer so the amount of air being pushed is no where near the same amount meaning you don't need as much for that application. you have to calculate your own amount to find what's perfect and just experiment. i completely eliminated all resonance down to 20hz with just fiberglass and polyfill. that's it. no unicorn magic or dragon scales. just basic acoustic materials.

 

[wje]

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T50RP is porous with fibers clearly present, running throughout.
 
 
 

 
T20RP dampener looks thicker and less porous without fibers running throughout.
 
 

 
Blue light behind open cup of T20RP shows that the mesh covering the cup vent serves only as a dust barrier, not as a dampener.
 
Note the stamp on the diaphragm - "Foster dp29 sz1d"  This is the sames stamp on all my T50RP's purchased in June, September, and December 2011.
 
 

Thanks for posting  your pics.  This truly seems odd.  I wonder how much of a difference in sound does the dampener paper make?  I compared my T20RP driver vs. my T50RP and both had the same looking paper (upon close inspection).  Now, I wonder if we were to take a hundred pair of T50RPs, I wonder how many of those 100 would deviate in regards to all using the same paper?  When I finished up the mods on my T20RP MKII headphones, it was really hard to hear any difference between the those and my T50RPs.  My T50RPs had the benefit of using the Shure 840 pads, but that was the only difference in the set up of the headphones.
 
I'd pull both drivers out and take pictures of the 50 and the 20 side-by-side (in my case), but the T20RPs have been sold and are all packed and ready to move on out.  

 

[rhythmdevils]

How could they sound the same when the 840 pads sound so different from the stock pads?

 

[FlySweep]

Nice to see the modding/experimenting still going strong..
 
I'll be putting my (black) Stax O2 pads up for sale soon.  Being that I use the Paradox almost exclusively, the CottonDryers have been mothballed.  I just wanted to give the folks here a heads up to jump on them before they hit the FS forum.  PM me if interested.

 

[proid]

Quote:

i know that obviously. that's why you use it in combination with something like fiberfill/polyfill. polyfill will make the driver believe it's in a larger enclosure basically making the overall distance from the driver to the fiberglass more expansive. thing is too thickness doesn't play the same rule with headphone enclosures cause the driver is much smaller compared to something like a 12'' woofer so the amount of air being pushed is no where near the same amount meaning you don't need as much for that application. you have to calculate your own amount to find what's perfect and just experiment. i completely eliminated all resonance down to 20hz with just fiberglass and polyfill. that's it. no unicorn magic or dragon scales. just basic acoustic materials.

That is a nice idea! I added another layer of filter wool, so it was driver -> filter wool -> fiberglass -> filterwool and i clear up the whole frequency, bass is even better, i can hear more detail but mid lost a bit wamth. It's really hard to get both deep tight bass and lush mid.

 

[glorydays]

Quote:

That is a nice idea! I added another layer of filter wool, so it was driver -> filter wool -> fiberglass -> filterwool and i clear up the whole frequency, bass is even better, i can hear more detail but mid lost a bit wamth. It's really hard to get both deep tight bass and lush mid.

 
Then you've absorbed the mids, but not the treble?Try with loose fiberglass closest to driver. The material with less density closest to driver? I suspect that filter wool reflect back much of the treble, making the sound picture unbalanced?
Try excluding the different freq. with EQ one at the time. Then you can easily hear if more details are let trough, and wether unpleasant ringing is gone or not. It should be possible to comfortably listen to higher volumes when the fq spectrum is balanced, and ringing is absorbed. Turn the volume up, and start exluding. Then you can find out wich fq range that causes ringing or distortion.
Listen for details when you exclude the 300 hz and 170 hz. The difference  between exclusion and presence should be minimal if the given backwaves are absorbed (for fq. below approx. 3 khz)
 
Quote:

i know that obviously. that's why you use it in combination with something like fiberfill/polyfill. polyfill will make the driver believe it's in a larger enclosure basically making the overall distance from the driver to the fiberglass more expansive. thing is too thickness doesn't play the same rule with headphone enclosures cause the driver is much smaller compared to something like a 12'' woofer so the amount of air being pushed is no where near the same amount meaning you don't need as much for that application. you have to calculate your own amount to find what's perfect and just experiment. i completely eliminated all resonance down to 20hz with just fiberglass and polyfill. that's it. no unicorn magic or dragon scales. just basic acoustic materials.

According to http://www.ethanwiner.com/acoustics.hl Fiberglass absorbs 500 hz when 1 inch thick and down to 250hz when 2 inches thick. However, this applies to a studio. How is it possible to remove down to 20hz? Have you measured this? Can you listen to higher volumes without hearing ringing? Do you experience the ultimate clichè about details, when 300hz and below is taken care of? How do pianos and flutes sound? If fiberglass is stuffed too hard, then it might start to reflect the upper fq?
 
In my experience, the 300hz and below is the most challenging spectrum, because it is difficult to identify the ringing and distortion from this. Its just like a big soup of sound. When the lower spectrum is taken care of, one should hear more details, and slight variations in tones from people singing.
 
 
 

 

[ambchang]

Quote:

Kind of a strange thought, but it has me worried.
I am going on a trip soon, and I wanted to bring my Fostex's. I did the clay mod, so I've got a bunch of clay in them. If they go through the xray with them, would the clay raise some suspicions?

No problems going through customs for me.  I used to bring my Fostex with all the clay and stuff on the plane every week.
 
I got a question about my portable amp once, and that was it.