Fostex T50RP Incremental Mods and Measurements

[Hutnicks]

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Well... building an enclosure is easier said than done. All I have for power tools is a hand drill/dremel. Every time I go to the hardware store I start lingering and wondering if I should pick up a table saw, band saw, drill press, table lathe... but I have neither the time, nor money, nor space for all that 

 
Those wet tile saws keep going on sale for quarter price though... which would be handy for kitchen/bathroom renos... 

Just need to take a hint from the big boys and practice design for manufacture. A dremel can be a wonderful thing. If you pick up some Roto Zip bits you will find that they fit the chuck perfectly and are a darn fine replacement for most variety of saw (hint, watch the torque it can pull you off course if you are not using a guide). There is also a little ceramic / metal bit Roto Zip makes which works a treat on thin sheet metal. You may not be able to come up with the Sennheiser molded swoop design but boxy Stax of yore is well within your reach. like ikea says "simple hand tools".

 

[bluemonkeyflyer]

DBV #3 Update: Modding just got easier.
 
I misplaced my last box of Rite Aid "Natural Absorbent Cotton." I searched everywhere but no joy. As I've previously described, Rite Aid "First Aid Rolled Cotton" performs similarly but requires "preparation."
 
Over 1 year ago, mrspeakers posted a modification to his Rastapants Mod using cotton balls. I tried different brands, sizes, and numbers of cotton balls in whatever mod iteration I was working on at the time (Not DBV #3). Cotton balls did not work so I kept looking for materials and happened to get good results with "Natural Absorbent Cotton." 
 
Fast forward to Now...No more "Natural Absorbent Cotton" and I've been looking for an easier application than the prep necessary when using "First Aid Rolled Cotton." I still have several boxes of Rite Aid "First Aid" cotton balls and decided to give them a try with DBV #3. 
 
I opened up one of my DBV #3's and removed the prepared cotton and prepared fiberglass. I placed 6 "First Aid" cotton balls, right out of the box and with No preparation in two columns, in the cup floors. I did not use any fiberglass. Everything else remained the same as described in my DBV #3 Pictorial/Tutorial. I closed them up and took a listen. The results? Cotton balls work, And they work really well with DBV #3 mod - with no preparation.
 
I have not yet tried teasing them apart (a little vs a lot). I have not tried altering the number of cotton balls + fiberglass. It is possible that doing so will further improve their performance. If you try this, please post your results.
 
 

 
 

 
6 unprepared cotton balls weigh 1.8 grams which is similar to the weight of "Natural Absorbent Cotton." Prepared "First Aid Rolled Cotton" weighs ~ 1.3 grams, IIRC.
 
 

 
6 Rite Aid "First Aid" cotton balls = Unprepared/un-teased
 
 
EASY DBV #3 MOD:
 
This mod is easy to build using cotton balls right out of the box and no fiberglass. I have not yet tried variations with teased cotton balls vs teased cotton balls + fiberglass vs unteased cotton balls + fiberglass. It sounds very good from top to bottom with very nice extension and details on both ends and clear midrange; no veil, no bass bloat, and no hollowness. You may get similar sound quality by substituting Paxmate Plus or Silverstone for Acoustipack Lite and ordinary plasticine for Newplast. Try what you have on hand. This mod sounds good with Shure 840 pads as well as mrspeakers' Dog Pads and Alpha Pads. His Alpha Pads and leather Comfort Strap make these headphones super comfortable - no hype.  I want a bit more treble with Alpha Pads so I will tune a bit more beginning with 5 x 60 x 70 mm fiberglass with thickness measured after firmly compressing it. 
 
 
     
3M Double sided tape around driver will secured stiff felt. Use a full width off the roll for the top and bottom sides of the drivers and 1/3 width for the other sides. Trim double sided tape around the driver screws so the tape lays flat.
 
 
 
 

3M Double sided tape segments will secure treble reflector.
 
 
 

18 mm treble reflector works best for me. I used thin card stock from ordinary packaging and dime coin as a template.
 
 
 
 

Acoustipack Lite in cup floor, masking tape over headband screw compartment, cup vents remain "stock," Newplast in the baffle compartments, and stiffened felt with no holes over back of driver and treble reflector. No holes = Less bass.
 
 
 
 

6 Rite Aid "First Aid" cotton balls over Acoustipack Lite and stiffened felt with four 3 mm holes over driver corner grids works best for me. Holes = More bass. Use 'em or lose 'em during tuning to satisfy your preferences.

 

[Snipe2p2]

So I'm a noob here as you can tell from my post count, however I've been reading up on various mods for quite some time and finally decided to take the plunge and see what the hype was about.
 
Unfortunately I'm extremely disappointed at this point as these things completely lack bass.  Have I done something wrong?  I'm comparing them to my GFs old Bose TP1s and even her HD-201s, both of which have more low end (the TP-1s have significantly more bass while the 201s are moderately more).  What's going on here?
 
My mods include:
Silverstone w/ silverstone rungs in cup floors
Self adhesive craft felt on "higher" cup floors on either side of the hanger screw post
Shure 840 pads
Plasticine loaded baffles
Stiff Craft felt over driver w/ 4 "bass boster" holes
Dime sized treble reflector under craft felt
Prepared Rite Aid Absorbant cotton weighing in at 1.8g
Covered baffle port
 
I've tried replacing the prepared cotton with cotton balls (not Rite-Aid - but 6 weighing in at ~3.2g).  I've also tried teased cotton balls weighing in at 1.0g.  I've tried removing cotton completely, covering the vents, partially covering the  vents, etc., and still I can't seem to get enough bass to hear the low end of pretty much anything.
 
Edit: I should add that I've tried running them off my Macbook Pro and Onkyo 616 receiver.  Not sure if this is the issue.
 
Any help would be greatly appreciated as I don't know if I'm missing something, expecting something different than I should, or what's going on but after a couple days of experimenting, I'm pretty frustrated and displeased.
 
Thanks in advance.

 

[Dyaems]

post pics please so that we would know what happened. also, the t50rp in the first place is not a bassy headphone at all, unless done a specific mod for it. by looking at what you did, i think you put too much treble-boosting materials in your t50rp
 
 
for that specific mod, try to do the following, although i kinda forgot the exact thing but the below info should be close:
- plasticine on the baffles
- open-cell foam (silverstone) on cup floors
- forgot if i put a craft felt on the back of the drivers, if ever i did, is suggest putting a thin craft felt on it.
- put something (like an electrical tape) at that vent/bass hole on the earside baffle, then poke it with a needle.
- cover the cup vents with an electrical tape? and make a small vent around 2-3mm rectangular (any shape, really) instead
- NO cotton material inside the cups, youll see why later
- i was using fa003 pads (and a supraaural pad at the center of fa003 pads that acts as a bass lense) before but im pretty sure that the 840 pads will give better bass amount
- make sure to put a masking tape or electrical tape part where the cups and baffles meet (i dont know what its called) for better sealing before putting the 840 pads.
 
its not super bassy but it is bassier than most t50rp mods there while still giving a clean sound. if the bass is too much, then thats the time you start putting cotton materials. no need to put a reflector but if you want, you can still put one behind the driver, not behind the craft felt.

 

[Snipe2p2]

Dyaems - thanks for the recommendations.  I gave it a try but still seem to be lacking low end. 
 
For what it's worth, I typically listen to hip hop and electronic.  I'm looking to be able to make out the bass line on songs like Tribe Called Quest's "Find a way" or 2 Pac's "Do for love".  Things like Daft Punk just seem to be severely lacking.  What am I missing here?

 

[chrislangley4253]

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Dyaems - thanks for the recommendations.  I gave it a try but still seem to be lacking low end. 
 
For what it's worth, I typically listen to hip hop and electronic.  I'm looking to be able to make out the bass line on songs like Tribe Called Quest's "Find a way" or 2 Pac's "Do for love".  Things like Daft Punk just seem to be severely lacking.  What am I missing here?

I listen to a lot of A Tribe Called Quest, the bass line comes through great on my t50rp mod. Same with Daft Punk. I'm not sure what you are missing. The t50rp have great extension, they go as low as you could ever want them to, but they aren't basshead cans. Maybe try some EQ man.

 

[chrislangley4253]

Just wanted to chime in real quick and say the Rite-Aid Cotton balls definitely do the trick.

The sound is very close to the meticulous cotton and fiberglass method. I highly recommend them.. Both for the sound and ease of use, I'm a little shocked by how well they work.

 

[bapspidoff]

Very cool, I definitely want to try the cotton balls now. I have these on hand: http://www.amazon.com/Rite-Renewal-Cotton-Balls-Triple/dp/B005V25E4E/ref=sr_1_2?ie=UTF8&qid=1363799584&sr=8-2&keywords=rite+aid+cotton+balls

Looks like different packaging though.... Think they'll work okay?
 
btw, BMF, what hole punch do you use for the felt? Mine is just terrible...

 

[chrislangley4253]

http://www.riteaidonlinestore.com/Rite-Aid-Cotton-Balls-Absorbent/dp/B0000AEG25?field_availability=-1&field_browse=3003305011&field_keywords=cotton+balls&field_product_site_launch_date_utc=-1y&id=Rite+Aid+Cotton+Balls+Absorbent&ie=UTF8&refinementHistory=brandtextbin%2Csubjectbin%2Ccolor_map%2Cprice%2Csize_name&searchKeywords=cotton+balls&searchNodeID=3003305011&searchPage=1&searchRank=salesrank&searchSize=12

 

[teofilrocks]

I'm eager to jump into the t50rp fray, but my one big concern is headband comfort, more than sound signature. I notice the Paradox version has an added suspension band, which I love the idea of (more than the Mr Speakers comfort strap). Any ideas on what it's from or where it's sourced? 

 

[peter123]

I'm eager to jump into the t50rp fray, but my one big concern is headband comfort, more than sound signature. I notice the Paradox version has an added suspension band, which I love the idea of (more than the Mr Speakers comfort strap). Any ideas on what it's from or where it's sourced? 

I bought a headband on ebay for less then usd 15 shipped to Norway. I can provide the link later when I'm on my laptop but for the next couple of days I only have my phone.

If you search for headband on ebay you'll find one kind with buttons that's said to fit grado and beyer among others, that's the one.

 

[bluemonkeyflyer]

Quote:

I'm eager to jump into the t50rp fray, but my one big concern is headband comfort, more than sound signature. I notice the Paradox version has an added suspension band, which I love the idea of (more than the Mr Speakers comfort strap). Any ideas on what it's from or where it's sourced? 

 
I made a suspension headband out of leather backed with closed cell foam, modeled after LFF's suspension headband, and held in place using "Hair Ties." It's very comfortable, cheap, and easy to make.
 
I have MrSpeakers' Leather Comfort Strap and Alpha Pads, too. For comfort, this combo is "Top Shelf" in my opinion and can't be beat. Mrspeakers' Comfort Strap is a steal at $15.00.  The headphones stay in place and there's no pressure points. His Alpha Pads are Super comfortable, every bit as comfortable as my LCD2 pads. They provide almost as good SQ (with my mods) as Shure 840 pads that "ain't half bad," comfort-wise. Seems to me I give up a bit of SQ (with my mods) for Much improved comfort using Alpha Pads. 

 

[teofilrocks]

I made a suspension headband out of leather backed with closed cell foam, modeled after LFF's suspension headband, and held in place using "Hair Ties." It's very comfortable, cheap, and easy to make.

I have MrSpeakers' Leather Comfort Strap and Alpha Pads, too. For comfort, this combo is "Top Shelf" in my opinion and can't be beat. Mrspeakers' Comfort Strap is a steal at $15.00.  The headphones stay in place and there's no pressure points. His Alpha Pads are Super comfortable, every bit as comfortable as my LCD2 pads. They provide almost as good SQ (with my mods) as Shure 840 pads that "ain't half bad," comfort-wise. Seems to me I give up a bit of SQ (with my mods) for Much improved comfort using Alpha Pads. 

Huh, so his leather comfort strap is more comfy than the suspension technique? Interesting. I might try the elastic hair ties, soft band, and grommet holes just for kicks and giggles. One final thing, I do wish that velours were able to hold up with these mods, Beyer velours are my close friends.

 

[bluemonkeyflyer]

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Huh, so his leather comfort strap is more comfy than the suspension technique? Interesting. I might try the elastic hair ties, soft band, and grommet holes just for kicks and giggles. One final thing, I do wish that velours were able to hold up with these mods, Beyer velours are my close friends.

Well, that's my opinion about mrpseakers' leather Comfort Strap. I think it's great. Same for his Alpha Pads comfort..."luxurious" comes to mind.
 
RE: Velour Pads - I've tried numerous mod configs with Shure Velour pads. I cannot make them work. The velour sucks out everything from 500 Hz, down, causing a Very steep roll off of -15 dB and funky humps in the upper mids and lower treble range With My Mods. I applied electrical tape to the inner "walls" of Shure velour pads which lifted the FR by 3 to 7 dB from 20 Hz to 500 Hz. I then added electrical tape around the outer "walls" and this lifted the FR by 7 to 10 dB from 20 Hz to 500 Hz, but that's still not enough for good bass and lower mids, IMO/IME...YMMV.

 

[teofilrocks]

I'll take your word for it about the velours. I don't see why I'd have some magically different results. Not even sure the Beyers would fit on it. Too bad, though, I'm a velour addict.