[stjj89]

   
Yes, it's reversible, and did calm down the treble. Happy modding!

 
zolkis, can I confirm that the pieces you used are C, D, E, and F as shown in the Fostex TH-900 tuneup kit instructions below, and that you followed all the instructions in the section "Step 4: Mod Driver Plate Rear"?

http://www.lawtonaudio.com/fostextuneupinstructions.html

 

[stjj89]

Chopped up two carbon pads as symmetrically as I could--105mm outer diameter, 72mm inner diameter, 8mm height in the front, 10mm height on the sides, and 12mm height on the back.
 

 
I rounded the top inner and outer edges, though I could possibly have been a little more aggressive. I didn't want to go too far though as I was worried it would affect the thickness and opening size which I so painstakingly measured out.
 
I have them on right now and they are indeed more comfortable (softer) than the Finnish carbon foam that playitloud sent me. It sounds good on my portable amp right now, but I will get a better idea of what changed when I bring it back to work tomorrow to run off my Fostex HP-A8.

 

[zolkis]

zolkis, can I confirm that the pieces you used are C, D, E, and F as shown in the Fostex TH-900 tuneup kit instructions below, and that you followed all the instructions in the section "Step 4: Mod Driver Plate Rear"?

http://www.lawtonaudio.com/fostextuneupinstructions.html

I don't have the headphones with me now, but I think I have used only D, perhaps F, i.e. against the direct reflections.

 

[stjj89]

I don't have the headphones with me now, but I think I have used only D, perhaps F, i.e. against the direct reflections.

 
Ah, I see. Did you try C and E as well and not like it, or are you doing it based on theory? I ordered all four parts, so I might just try putting all of them on.

 

[stjj89]

Updates: I got the dampening strips from Mark Lawton and will be trying to install them tonight. Also, I will be bringing my modded TH-900 to the upcomng San Francisco Head-Fi meet to see what other head-fiers think of it

 

[playitloud]

  Updates: I got the dampening strips from Mark Lawton and will be trying to install them tonight. Also, I will be bringing my modded TH-900 to the upcomng San Francisco Head-Fi meet to see what other head-fiers think of it

 
Great. Good to let other headfiers try the modded version of the TH900. It would be even better to compare the modded version directly to a 'standard' TH900.
I am curious how well you like the modification? did you try different things? What effect did it have, and what is your 'final' version? What do you consider the most important changes..... Please inform us.
 
Your effort is much appreciated.

 

[stjj89]

   
Great. Good to let other headfiers try the modded version of the TH900. It would be even better to compare the modded version directly to a 'standard' TH900.
I am curious how well you like the modification? did you try different things? What effect did it have, and what is your 'final' version? What do you consider the most important changes..... Please inform us.
 
Your effort is much appreciated.

 
It would be awesome to compare the umodded and modded TH900 side by side. This would be particularly easy with my Fostex HP-A8, since it has two headphone outputs.
 
I am definitely liking the modification so far. After cutting out a pair of well matched pads using the Amazon carbon foam, I *think* the cans sound a little more "right" now, but I was too lazy to swap between the two types of foam pads to really find out what the differences are. To be honest, I haven't switched the felt rings and cup dampers yet because I'm kind of worried that I will screw something up by opening up the headphones and replacing the mod components too much. I am also still really bad at taking the pads on and off. I am trusting in the testing that you and zolkis have done and sticking with the "optimal" configuration for now.
 
I was tempted to try putting the ecru circles in the cups instead of the white felt circles, as you mentioned that they would reduce air and help thicken the sound a little. However, I am really liking the soundstage I am getting on these cans right now (they sound like open cans!) and I'm worried about losing any of that. Since I will be installing Lawton's damper rings on the back side of the driver tomorrow, I might give this a try and report back.
 
Overall, I love how the mids are more forward now and how the TH-900 now sounds more like a capable neutral can. I do wish they were a little warmer and "thicker" sounding, but I suspect they might just not be meant to sound that way (they definitely did not sound warm in stock form). My only two complaints are that 1) the treble is still not as refined or realistic as that I'm hearing on my HE-560 and other planars, and 2) the ears sometimes touch the driver grill because of the shorter foam pads, but adjusting the headphone a little bit forward usually solves this problem for me. Thanks again for pointing me in the right direction with these mods!

 

[playitloud]

Great to hear you like the mods. My experience with planar headphones is indeed that they have a thicker sound. Some call it more visceral. That a bit of their trademark.
 
You can increase the thickness of the TH-900 but it will be at the expense of openess and airiness. You loose some 'detail' information.
 
The Lawton damper rings are a good idea. I found out that I  still have them installed. Completely forgot about them. Guess I was a bit worried to remove them....I have no problem with treble, but I use a tube DAC and tube amp, and I am old and listen loud, which implies my hearing is probably not as accurate as yours :-D.
 
Keep the white felt pads in the cups, and install the Latwon ring dampers. I think you will be fine after that. Keep in mind that by modding you cannot completely change the character of the headphone. You can maximize on its capabilities. Great bass and very open sounding for a closed can, and reduce its shortcoming to an extent by bringing the midrange more forward. If you try to make it a different headphone you somehow end up with a mediocre headphone albeit with prefered sound signature. Enjoy.

 

[stjj89]

  Great to hear you like the mods. My experience with planar headphones is indeed that they have a thicker sound. Some call it more visceral. That a bit of their trademark.
 
You can increase the thickness of the TH-900 but it will be at the expense of openess and airiness. You loose some 'detail' information.
 
The Lawton damper rings are a good idea. I found out that I  still have them installed. Completely forgot about them. Guess I was a bit worried to remove them....I have no problem with treble, but I use a tube DAC and tube amp, and I am old and listen loud, which implies my hearing is probably not as accurate as yours :-D.
 
Keep the white felt pads in the cups, and install the Latwon ring dampers. I think you will be fine after that. Keep in mind that by modding you cannot completely change the character of the headphone. You can maximize on its capabilities. Great bass and very open sounding for a closed can, and reduce its shortcoming to an extent by bringing the midrange more forward. If you try to make it a different headphone you somehow end up with a mediocre headphone albeit with prefered sound signature. Enjoy.

 
Thanks for the advice. That was what I was thinking as well. I will leave the white felt in there then. May I know if you put all 4 Lawton damper rings in each of your cups? That is, did you apply parts C, D, E, and F in the instructions here?
 
http://www.lawtonaudio.com/fostextuneupinstructions.html
 
I ask because zolkis said he only did D and F.

 

[stjj89]

 
What do you consider the most important changes..... Please inform us.

 
I just realized that I missed this part of your question. From doing the two stages of the mod incrementally, this is my impression of how each part of the mod affects the sound of the TH900:
 
Earpad mod

1. Brings mids forward, making the headphone sound more balanced and neutral
2. Vocals more engaging and easier to follow
3. Some increase in treble sparkle and clarity (possibly because of the removed grill cloth)
4. Not much change in bass, but it is less (over)emphasized because the mids are now more in line 

 
Felt Cup Dampers + Felt damper rings

1. Bass bloom/bloat eliminated--bass is tighter and extends deeper, while still having the same impact and slam
2. More detail and refinement (not 100% sure about this one since I didn't do before/after comparisons, but that was the feeling I got)

 
I feel like the earpad mod makes a bigger difference, but the improvement to the bass from the felt mods are a big win in my book, and definitely make it worth doing. The earpad mods fixed the most glaring flaw of the TH900 in my books (slightly recessed mids), and the felt mods fixed its second biggest problem (the boomy bass), and took the refinement of the sound a step further.
 
I will report back on the Lawton ring dampers soon. I might even do a little printout of the mods (w/ pictures) to bring to the head-fi meet in case anyone there is curious about them

 

[playitloud]

I agree with your impressions. The earpad mod indeed brings the midrange more forward, probably because the ear is closer to the driver. Furthermore, it does a lot in making the sound more open and spacious, probably because of the open structure of the carbon foam. That makes the sound less closed in.
 
The felt mods do increase refinement quite a bit to my opinion. But I agree it is more subtle. By bringing the mids more forward, you already hear more of the score such as vocal inflections. The felt mods makes these extra nuances smoother and more natural. The sound is less dry, notes last longer, decay improves. The dimensions of the felt damper affect the 'bass boom', especially the outer dimensions. If you decrease it further you will have less bass. But  the Fostex needs to be a bit of a 'bassy' headphone proably because of its frequency dip at about 500 Hz. We spend a lot of time to get that right.
 
Keep us posted, you impressions are much appreciated. I am very curious how other head-fi'ers will react at the San Fransisco meet.
 
Oh, I forgot. I checked and I have the complete Lawton damper ring mods installed (C, D, E, and F), and I do not feel the need to change that. 

 

[stjj89]

Wow, I am quite impressed by the Lawton backplate damping upgrade. The treble definitely got less tizzy and more natural, making it much easier to listen to. The headphone sounds very slightly warmer/darker now, but I suspect that this is just the result of me being able to turn up the volume higher now that the treble is smoothed. This truly did fix the treble and I am loving the end result!
 
Warning to anyone attempting these mods--it is easy to strip the screw holes on the Fostex TH900 cup. I stripped one of them from repeatedly attempting to get the screw in when the cup was slightly misaligned, and now I cannot fit get my screw into one of the four holes on the right cup. This is not the biggest deal since the other 3 screws hold the cup in very securely, but I am looking into getting this fixed with some wood putty. Be careful out there, modders!

 

[AppleheadMay]

  Wow, I am quite impressed by the Lawton backplate damping upgrade. The treble definitely got less tizzy and more natural, making it much easier to listen to. The headphone sounds very slightly warmer/darker now, but I suspect that this is just the result of me being able to turn up the volume higher now that the treble is smoothed. This truly did fix the treble and I am loving the end result!
 
Warning to anyone attempting these mods--it is easy to strip the screw holes on the Fostex TH900 cup. I stripped one of them from repeatedly attempting to get the screw in when the cup was slightly misaligned, and now I cannot fit get my screw into one of the four holes on the right cup. This is not the biggest deal since the other 3 screws hold the cup in very securely, but I am looking into getting this fixed with some wood putty. Be careful out there, modders!

 
 
 
Glad to hear the dampening makes a difference on its own, something I never tried.
The pads alone make a difference as well, but not for the better, these need to be combined with either the dampening or more likely the cups I think.
Screwed screwhole problem: a pair of La cups. These do make a big difference, probably the wood has something to do with it but surely the cup dimensions will count for a lot.

 

[stjj89]

 
Screwed screwhole problem: a pair of La cups. These do make a big difference, probably the wood has something to do with it but surely the cup dimensions will count for a lot.

 
I might consider that some time down the line, but definitely not now. They're pretty costly, and I actually really like the look of the urushi-lacquered TH900 cups. Also, my current set of (zolkis-)mods will probably be thrown way off by different cup dimensions and material. Thanks for the suggestion though!

 

[Luckbad]

Anyone know of replacement TH900/TH600 earpads that are slightly taller inside (top to bottom) than stock and don't reduce the bass? I have tall ears and the inside of the stock pads touches the top and bottom of my ears slightly.