[kalbee]

Instead of mass dampening, I assume you guys tried sandwiching different density materials and it wasn't as efficient?
I plan on trying dampening methods used in things like conference rooms n auditoriums (super ghetto version with cardboard since I can't slice up wood :S). Will let you guys know if I get any success.
 
If I has a broad idea on how my FR graph looks like it would be easier to tackle but eh... I'll enjoy messing around. Once my exams are over.

 

[RexAeterna]

Instead of mass dampening, I assume you guys tried sandwiching different density materials and it wasn't as efficient?
I plan on trying dampening methods used in things like conference rooms n auditoriums (super ghetto version with cardboard since I can't slice up wood :S). Will let you guys know if I get any success.

If I has a broad idea on how my FR graph looks like it would be easier to tackle but eh... I'll enjoy messing around. Once my exams are over.

are you talking about those acoustic panels? no you don't need to use wood with headphones. the material under those panels is most likely fiberglass. they put it on wood panels to make it look pretty and make it easier to take off and put back on anywhere. they use cloth over the fiberglass cause it needs to breath in order to absorb properly. measuring though is totally different when coming to headphones compared to speakers cause of the size of the enclosure and driver but of course uses the same basic principles and materials for proper absorption. just takes time and patience to find out the correct layering/combination and amount to get it the way you want it.

 

[kalbee]

Yeah, its fiberglass and other kind of spray-on foam, depending on how they designed it. But that's essentially one of the formats I want to try-- panels with soft absorbing materials behind. This way I get waves getting trapped behind through the slits, and if the panels themselves move the stuff behind will absorb the movement. There's actually another type I want to try, but for that I will use cardboard for starters.
Tissue box, you shall die. In the name of science!
 
I wanted to try wood for its reflective properties. Though I reckon the crappy wood I wanted to use (some crappy fake Jenga tower that's too rough to play Jenga with lol... can't pull anything out without total collapse) would probably absorb some too. They're a little too thick to fit in though.
 
Guess I'll look into coffee stir sticks/popsicle sticks.

 

[wje]

Quote:

yea. simple to remember it as fiberfill too. people should read up on acoustic materials for speakers. very simple materials,dirt cheap too. also same materials for acoustic treatment for rooms and studios that's been proven for the past 40 or more years with data to back up their absorption properties. just have to read up on google and audiokarma can be pretty good place to ask around too since they have a dedicated forum for room treatments and have links to data and information on the materials.

Was it better to use batting - (e.g. the stuff designed for quilting and comes in sheets) as opposed to the loose fill type, which would be used in pillows?
 

 

[RayPierrewit]

Perhaps I haven't done enough homework on the subject, but I've got a probably very elementary question. What exactly is the function of the bass vents? How do they work? I ask because I was perusing this thread last night and I read an interesting suggestion by Botbyte. He says, in post #2422, "I found to allow the vent in the cups to shoot directly to the driver allows a lot more air to move about.". Would this then produce more or better bass?
 
What about the ear side bass lens (or however it's called). What is it's function? From what I gather it is unanimous that it be left unobstructed and untampered, yes?
 

 

[glorydays]

Disperse that backwaving arse:
 
http://www.google.no/imgres?q=acoustic+dampening&hl=no&sa=X&biw=1280&bih=707&tbm=isch&prmd=imvns&tbnid=oP2MNssyjklosM:&imgrefurl=http://en.wikipedia.org/wiki/Acoustic_quieting&docid=F3GGKIGp2q3LXM&imgurl=http://upload.wikimedia.org/wikipedia/commons/5/52/Anechoic_chamber.jpg&w=250&h=188&ei=eGU4T5iaHbD44QT-3_CGDg&zoom=1

 

[kalbee]

Quote:

Perhaps I haven't done enough homework on the subject, but I've got a probably very elementary question. What exactly is the function of the bass vents? How do they work? I ask because I was perusing this thread last night and I read an interesting suggestion by Botbyte. He says, in post #2422, "I found to allow the vent in the cups to shoot directly to the driver allows a lot more air to move about.". Would this then produce more or better bass?
 
What about the ear side bass lens (or however it's called). What is it's function? From what I gather it is unanimous that it be left unobstructed and untampered, yes?
 

My answers may not be 100% correct but, increasing the size of the bass vents may increase the bass size. Increase it too much and you lose the bass? as for the bass lens, anyone using stock pads would probably not touch the ear-side felt cause your ears are always in contact with it. Though most people change them off!
In either cases, it's to allow more air displacement for the bass. Can't explain the specifics... don't fully get it either.


Quote:

Disperse that backwaving arse:
 
http://www.google.no/imgres?q=acoustic+dampening&hl=no&sa=X&biw=1280&bih=707&tbm=isch&prmd=imvns&tbnid=oP2MNssyjklosM:&imgrefurl=http://en.wikipedia.org/wiki/Acoustic_quieting&docid=F3GGKIGp2q3LXM&imgurl=http://upload.wikimedia.org/wikipedia/commons/5/52/Anechoic_chamber.jpg&w=250&h=188&ei=eGU4T5iaHbD44QT-3_CGDg&zoom=1

Yeah!! Overkill tho xD
Though doing this with purely plasticine seems feasible. Instead of denting the surface with philips, use flathead instead!
 
 

 

[Nevod]

Egg crates are what is often used if there is need to reduce reflections cheaply.
There is some sound-proofening foam like Paxmate with similar 'wavy' top surface.
 
Also, regarding wave physics.. Moth's eyes have a surface  that fights reflections as well.
 
 
 
Quote: Wikipedia

Moths' eyes have an unusual property: their surfaces are covered with a natural nanostructured film which eliminates reflections. This allows the moth to see well in the dark, without reflections to give its location away to predators.^[3] The structure consists of a hexagonal pattern of bumps, each roughly 200 nm high and spaced on 300 nm centers.^[4] This kind of antireflective coating works because the bumps are smaller than the wavelength of visible light, so the light sees the surface as having a continuous refractive index gradient between the air and the medium, which decreases reflection by effectively removing the air-lens interface.

I think the paxmate 'cubes' have similar properties. There should be more thought put into them..

 

[kalbee]

Hm... egg crates seem like a fine idea for speakers but I can already imagine myself having difficulty fitting that in the cups! Good to know though, I can give it a shot maybe, that and the cubes. Btw, the white earpads look awesome on those T20RP!
 
In terms of soundstage, I am starting to wonder if paxmate doesn't kill it. Anyhow, tried mass loading with cotton today, seems to have a bit of an effect. Now just wondering if I'm crazy that the left channel sounds louder, or the amounts I put was too uneven.

 

[c61746961]

Hmmm, I wonder...

 

[Nevod]

Quote:

Hm... egg crates seem like a fine idea for speakers but I can already imagine myself having difficulty fitting that in the cups! Good to know though, I can give it a shot maybe, that and the cubes. Btw, the white earpads look awesome on those T20RP!
 
In terms of soundstage, I am starting to wonder if paxmate doesn't kill it. Anyhow, tried mass loading with cotton today, seems to have a bit of an effect. Now just wondering if I'm crazy that the left channel sounds louder, or the amounts I put was too uneven.

 
 
Thanks! I also think they look great. 
As for egg crates, it's not the crates, it's their form - they deflect sound sideways, where it is again re-deflected by another 'hill' of the crate, and so on and so on. These slotted deadeners work same way, just that they work better because they are efficient for a wider range of angles. I've thought about putting cardboard cones into cups, but couldn't really see how to do it properly, with still having place for everything else. Maybe interleaving cubes with cones, but that would take a long time to make so many cones. 
 
As for soundstage, I don't know. It's a question what actually forms the soundstage. I just aim for a sound that is most correct from technical standpoint, i.e has flattest responce, has no leftover sound from previous time (as in resonances and reflections) etc. There's some on that in the Loudspeaker and Headphone Handbook, but I didn't read it deeply yet.
 
Difference may be due to uneven amounts, leaks, bad contact in jack.
 
Quote:

Hmmm, I wonder...

These (as in those used on rifle optics) kill off-axis beams by absorbing them (black colour) and re-reflecting within the honeycomb tube to get beam to re-reflect and get absorbed many times. Maybe could be used on back side of the driver together with dispersors. Or on front side, but I don't think it's really needed there. 
 

 

[Nevod]

 
ri_toast,
There's never really that hot here. Besides, I've put the plasticine over a heating radiator, and it didn't melt, just got softer.
 
mrspeakers's idea about replacing most of baffle plasticine with just dynamat to increase space in the cups intrigues me. I'm just afraid wouldn't the baffle get too light that way so it would create problems with the bass. I don't really know, maybe it's no problem really. Though we can always put MORE dynamat on ear side.
 
RayPierrewit,
I may be not very correct with bass vents, but afaik they tune driver behaviour when it works in pressure mode - on low frequencies. More open ports - less pressure on back of the driver. Bass lenses reduce amount of high frequencies coming from edges of the driver, thus 1)Their amount is reduced, relatively increasing amount of bass 2)Dips and peaks from interference of the waves coming from driver's center and edges are reduced - HF responce is dominated by driver's center.

 

[DaBomb77766]

Quote:

Hmmm, I wonder...

I'm pretty sure that's normally used in wind tunnels...

 

[proid]

My old config:
-Mass load with plasticine
- white driver felt removed
-dynamat and paxmate the cup
-1.5 layer of transpore
-stock bass port felt
-bass port covered 3 slot with electrical tape
-dynamat and paxmate baffle's ear side
-earside felt removed
-stuff cotton and filter wool inside the cup
-Recable with canare L-4e6s
-Shure 840 earpad
-pad lifter with cotton
I have very good sound with this config but hf sound harsh, especially "s", "sh", ... so i remove 0.5 layer of transpore, it helped taming hf but there are too much bass even when i closed all bass port with electrical tape. I got some fiberglass, stuff it in the cup, i think bass go just a little deeper, the sound was cleaner and harsher than cotton. In the end, i think i prefer cotton + filter wool to fiberglass + filter wool. Filter wool really has posstive effect: it open up the soundstage and let me hear more detail, fiberglass and cotton is a win-win situation. Now i will use 1.33 layer of transpore, remove some plasticine, hope it will make the sound more balance.

 

[Nevod]

I've run some SineGen testing on mine. Looks there's really some resonance around 920-930Hz and 11kHz. Also something like slight peak at 5kHz, but I took a peek at equal loudness curve and seems that it's just hearing effect. Also real falloff after 15kHz, but again I don't know the cause.
 
Cotton has already been suggested as a cure for that, so I'll use that, not now though, really lazy to open them up.
 
What bugs me the most is that they seem to need to be 'heated up' each time I listen to them. Sound really changes during first 30 minutes, becomes more detailed and less mudded (most of the mud is from soundcard I suppose). At first they sound like something's wrong but then they become addictive.
 
proid,
What's the difference between cotton and filter wool? I fail to see any difference from pictures.