[hans030390]

I'm having a real hard time keeping these 840 pads on with Silverstone foam underneath (1 layer donut, and an additional layer on back half). Right now, they're taped on! Is that normal? How are you keeping your's on, kingoftown1?

 

[proid]

Quote:

Just tried to take a couple pics of the pad mods, but I only have my cell phone camera and it's way too dark right now.  Until I take new ones tomorrow, here's what I've got.  (Also just ordered more Silverstone so I can actually fill these new pads out properly)
 
 
 
 

 
Can you post some more pic inside of the pad? I want to see how thick is the acoustic foam with this pad mod.

 

[bluemonkeyflyer]

That's a good question and one I've considered with every mod I've tried. Granted, my methodology includes uncontrolled variables and isn't even single-blinded. I don't have or use any sophisticated measurement equipment or a dummy head other than the one between my ears.

I have used a standard A/B comparison method of one mod at a time referenced to a non-modded set and often other modded sets and LCD2's - SPL matched and played through the DAC and amp of my Dacmini. I listen to tunes I know very well and play various sections back and forth and make my subjective, opinion-based assessment of what sounds better to me. BTW, any ratings of "X% of the SQ of LCD2" are rough, subjective opinions, too.

I have been surprised many times how a seemingly miniscule change results in significant results - favorable and unfavorable. Examples include stiffened vs unstiffened felt, the number (even fraction) of bass port slots covered, type and number of tape layers, amount of plasticine used, and many more. I have heard how one mod may require additional mod experiments to fix an unwanted outcome. This can be challenging once non-reversible mods are made; for example, removing the stock driver felt may require adjusting cup volume, changing the ear pads, and/or closing bass port slots.

So, what's the science behind such small amounts of Dynamat having any real effect on SQ? Minimal other than understanding experimental methods, making only one mod at a time, 100's of individual mods across 6 sets of T50RP's, and having no agenda other than learning from one another and having fun. When it stops being fun, I'm done.

I try to word my posts as reports of my impressions and my opinions, not as universal facts, absolute truths, or necessarily right for anyone but me. Everyone must try a mod and draw their own conclusions, not rely on what someone else says or what test equipment and charts might show. "If it sounds good to you, it sounds good to you" and the opposite is also true.

Now, did I mention confirmatory bias, egos and personality factors, cognitive dissonance, and placebo effects? :wink_face:

Bottom line: Test for yourself and trust your ears.

Cheers

BMF and Armaegis, about the ear-side Dynamat in BMF pants #6. With all the mass damping from the huge amount of plasticine in the baffles, how is such a relatively small amount of Dynamat making a significant change in the sound? What's the science here?

 

[Armaegis]

Quote:

BMF and Armaegis, about the ear-side Dynamat in BMF pants #6. With all the mass damping from the huge amount of plasticine in the baffles, how is such a relatively small amount of Dynamat making a significant change in the sound? What's the science here?

Mass loading with plasticine will reduce the amplitude of the reactive vibrations produced by the driver. Dynamat will more quickly dampen those same vibrations after they've been produced.  For those who want the physics, it is similar to this:
http://en.wikipedia.org/wiki/Damping#Example:_mass.E2.80.93spring.E2.80.93damper
Plasticine mostly adds to the mass, dynamat mostly adds both mass and spring damping. Both have an effect on the spring constant and resonant frequency, but let's gloss over that for the sake of keeping things reasonably sane and understandable.
 
As for whether or not it makes a "significant" change in sound... *shrug*

 

[LFF]

Quote:

Everyone must try a mod and draw their own conclusions, not rely on what someone else says or what test equipment and charts might show. "If it sounds good to you, it sounds good to you" and the opposite is also true.

 


I agree. Every single person who has PM'd me has received the same advice. Try a few mods and trust your ears.
 
If you try a RastaPants2 and love the results...AWESOME! If you try a BMF # x and love the results....AWESOME!
 
It was merely pure luck and coincidence that I loved the results of my Paradox and that they happened to measure well - I simply tried some new things and tuned them by ear. I was clueless about the results until Purrin said "wow". Even then I still feared they might measure poorly. If they had measured poorly, I'm sure Purrin would have posted the results anyway and I'm sure he would have been rather blunt about it. I certainly would not have objected to it, especially since Purrin volunteered his time and know-how. Regardless, I would still be a happy camper because they sound awesome to me and charts would serve to help people know what they were getting into if they decided to do a similar mod.
 

 

[drez]

Quote:

i went ahead and covered nearly the entire interior surface of the cups with thick 4mm-ish felt, leaving the vent uncovered for tuning the bass with tape.  here's the stuff i'm using from Lowes: http://www.lowes.com/pd_54164-255-4740095N_0__?productId=3034727&Ntt=felt+pads&pl=1&currentURL=%2Fpl__0__s%3FNtt%3Dfelt%2Bpads&facetInfo= .  it's dense wool-like material that's pretty stiff to work with and cut, but the glue backing is sticky.
 
i read most everyone here using Paxmate, but i'm having a hard time believing that it's any better than the felt?  btw, the extra felt does sound better.

I don't think there's any reason to assume foam is better than felt, but the two are quite different in terms of the surface area, density etc therefore should be slightly different in performance.  My next mod will be with some acoustic felt but first I need to sort out a recable, cant stand this channel imbalance.  I would also suggest that having equal amounts of damping is important if you are trying to achieve good channel balance, as more damping kills efficiency therefore imbalanced damping will cause imbalanced efficiency of the drivers.

 

[kingoftown1]

Quote:

I'm having a real hard time keeping these 840 pads on with Silverstone foam underneath (1 layer donut, and an additional layer on back half). Right now, they're taped on! Is that normal? How are you keeping your's on, kingoftown1?

Hey, I don't have any Silverstone under the pads yet (it should be coming in on wednesday).  Right now I'm just using some random squishy white craft foam, but i'll be sure to update with some earside foam configurations when I get the chance.  As for my pads, hans, I cut off the strip that holds them on and sewed together a deeper version out of some black pleather.
 
Proid--I'll snap some more pics of the pads off the headphones later today
 

 

[fishski13]

Quote:

I don't think there's any reason to assume foam is better than felt, but the two are quite different in terms of the surface area, density etc therefore should be slightly different in performance.  My next mod will be with some acoustic felt but first I need to sort out a recable, cant stand this channel imbalance.  I would also suggest that having equal amounts of damping is important if you are trying to achieve good channel balance, as more damping kills efficiency therefore imbalanced damping will cause imbalanced efficiency of the drivers.

a good point about equal damping in both cups.  i made an effort to cut identical felt pieces for each cup for balanced absorption.

 

[wdahm519]

Quote:

So, what's the science behind such small amounts of Dynamat having any real effect on SQ?

Speaking of which, I tried putting a layer of FatMat under the two layers of SilverStone acoustic foam donuts and I think it may have slightly helped extension.  I don't have a 2nd set to A/B like you can, but I noticed the extension in the treble somewhat notably.  Bass extension I can't really say, it sounded about the same.  Thanks for pointing that out because I think it was a success overall.
 
As for my acoustic foam donuts, I've found a good design that covers the reflective surfaces with the first layer but doesn't affect the seal by pushing my ears away from the pads.  The first layer of the acoustic foam fits exactly over the FatMat layer on the ear side of the baffle.  If you cut a shape exactly like the oval of the headphone, and then cut out the diamond in the center for the driver plus the notch for the pressurization equalization you'd have the shape for the FatMat and first layer of the acoustic foam.  The second layer of acoustic foam is just literally a doughnut shape, the outside radius being the radius of the ear-side baffle, and the inner radius being however large your ear is so the pad doesn't touch your ears.  The second acoustic foam layer pushes the earpads away from the headphones and really allow a better seal and increased SQ.  
 
I've done a lot of iterations with various acoustic foam doughnuts and so far this set up probably gives the best SQ for pretty good comfort.
 
 
EDIT:  This is for SRH 840 pads ONLY, but you can try it for stock pads if you want.
 

 

[Twinster]

Just place my order for the T50rp (in Canada). The funny part is that all the place I called their sale representatives was all wondering why they sold so many lately because they had the product on the shelf not moving for a long while and suddenly they were all sold out. You guys realized the economic impact you have created???

  Now do the same with a GM or Chrysler car

.

 

[hans030390]

Quote:

Hey, I don't have any Silverstone under the pads yet (it should be coming in on wednesday).  Right now I'm just using some random squishy white craft foam, but i'll be sure to update with some earside foam configurations when I get the chance.  As for my pads, hans, I cut off the strip that holds them on and sewed together a deeper version out of some black pleather.

Oh, cool! Couldn't tell from the pictures, but they look great!

 

[micmacmo]

 
Quote:

Mass loading with plasticine will reduce the amplitude of the reactive vibrations produced by the driver. Dynamat will more quickly dampen those same vibrations after they've been produced.  For those who want the physics, it is similar to this:
http://en.wikipedia.org/wiki/Damping#Example:_mass.E2.80.93spring.E2.80.93damper
Plasticine mostly adds to the mass, dynamat mostly adds both mass and spring damping. Both have an effect on the spring constant and resonant frequency, but let's gloss over that for the sake of keeping things reasonably sane and understandable.
 
As for whether or not it makes a "significant" change in sound... *shrug*

Thanks for the link, Armaegis. I haven't used the calculus in 25 years and can't claim to understand the math. But the illustration suggests that a dampening material acts like a car's springs and shocks rolled into one. I'll assume that both Dynamat and plasticine have different spring constant and damping coefficients, and therefore work in complementary ways. Is that a reasonable generalization?
 
Quote:

So, what's the science behind such small amounts of Dynamat having any real effect on SQ? Minimal other than understanding experimental methods, making only one mod at a time, 100's of individual mods across 6 sets of T50RP's, and having no agenda other than learning from one another and having fun. When it stops being fun, I'm done.

...

Bottom line: Test for yourself and trust your ears.
Cheers

Thanks, BMF. I think I've said it before and I'll say it again: Thanks for the rigour and damn-the-torpedoes attitude you bring to your modding experiments. It's really invaluable knowledge. As for myself, I'll throw any household material behind the drivers, from furniture bumpers to household sponges, as long as the mod is reversible. But when it comes to using sharp implements to scrape off well-cemented felt near the driver and adding a layer of sticky goop in its place, I'm a bit more cautious and questioning. But the fact that you'll be making the mod to your T50s across the board and that wdahm519 was able to repeat your results is reason enough for me to try it. Did you consider sanding the felt off, instead of scraping?
 
 

 

[Armaegis]

Quote:

 
Thanks for the link, Armaegis. I haven't used the calculus in 25 years and can't claim to understand the math. But the illustration suggests that a dampening material acts like a car's springs and shocks rolled into one. I'll assume that both Dynamat and plasticine have different spring constant and damping coefficients, and therefore work in complementary ways. Is that a reasonable generalization?
 
 

Close, but not quite. I'm also trying to steer away from using the word "damping" by itself as it needs to be differentiated between vibration damping and acoustic damping.
 
Whenever the diaphragm creates sound, there's an equal and opposite reaction that pushes the magnet/driver assembly in the opposite direction (what I called the "reactive vibrations" from earlier). Since the diaphgram is very light compared to the driver assembly and baffle, the majority of the energy from your audio signal goes into moving the diapragm, but the assembly still moves a little bit. This little bit of movement affects the cleanliness of the sound reaching your ear.
 
Using a car analogy, think of the driver assembly motion as hitting a speed bump. Mass loading (such as with plasticine) simply makes the car heavier and less reactive to the bump. The "wobble" of your car afterwards will be smaller and also slower compared to a light car with the same springs and shocks. Dynamat is a bit of both making the car heavier and giving it better shocks. The shocks more actively absorb the vibration and bring the oscillations to zero faster. Plasticine does affect the shocks a bit, but not as much. For our purposes nothing really significantly affects the springs, which in the headphone case is the transverse stiffness of the baffle; you have to do a transplant for that.
 

 

[micmacmo]

Thanks for the explanation, Armaegis. It make sense.
 
FYI for Canadian modders, there's a Lethbridge, AB company that sells a butyl-based vibration dampener called B-Quiet Ultimate that's comparable to Dynamat Extreme. (It's been mentioned in this thread earlier, I believe.) I contacted them and they agreed to send me a square foot of B-Quiet Ultimate for $9, including shipping via Canada Post. 

 

[bluemonkeyflyer]

I'm happy to hear you like what you hear.  

 
Quote:

Speaking of which, I tried putting a layer of FatMat under the two layers of SilverStone acoustic foam donuts and I think it may have slightly helped extension.  I don't have a 2nd set to A/B like you can, but I noticed the extension in the treble somewhat notably.  Bass extension I can't really say, it sounded about the same.  Thanks for pointing that out because I think it was a success overall.
 
As for my acoustic foam donuts, I've found a good design that covers the reflective surfaces with the first layer but doesn't affect the seal by pushing my ears away from the pads.  The first layer of the acoustic foam fits exactly over the FatMat layer on the ear side of the baffle.  If you cut a shape exactly like the oval of the headphone, and then cut out the diamond in the center for the driver plus the notch for the pressurization equalization you'd have the shape for the FatMat and first layer of the acoustic foam.  The second layer of acoustic foam is just literally a doughnut shape, the outside radius being the radius of the ear-side baffle, and the inner radius being however large your ear is so the pad doesn't touch your ears.  The second acoustic foam layer pushes the earpads away from the headphones and really allow a better seal and increased SQ.  
 
I've done a lot of iterations with various acoustic foam doughnuts and so far this set up probably gives the best SQ for pretty good comfort.
 
 
EDIT:  This is for SRH 840 pads ONLY, but you can try it for stock pads if you want.
 

 

Your pleasure is mine.  I'm happy that the fun I'm having with modding is helpful to you.  

 
I did not consider sanding.  The work space is small.  I hate sanding.
 
Quote:

 
Thanks for the link, Armaegis. I haven't used the calculus in 25 years and can't claim to understand the math. But the illustration suggests that a dampening material acts like a car's springs and shocks rolled into one. I'll assume that both Dynamat and plasticine have different spring constant and damping coefficients, and therefore work in complementary ways. Is that a reasonable generalization?
Thanks, BMF. I think I've said it before and I'll say it again: Thanks for the rigour and damn-the-torpedoes attitude you bring to your modding experiments. It's really invaluable knowledge. As for myself, I'll throw any household material behind the drivers, from furniture bumpers to household sponges, as long as the mod is reversible. But when it comes to using sharp implements to scrape off well-cemented felt near the driver and adding a layer of sticky goop in its place, I'm a bit more cautious and questioning. But the fact that you'll be making the mod to your T50s across the board and that wdahm519 was able to repeat your results is reason enough for me to try it. Did you consider sanding the felt off, instead of scraping?