Fostex T50RP Incremental Mods and Measurements
Jan 8, 2013 at 10:06 PM Post #316 of 2,832
Quote:
Update: I edited and added additional information and pictures to "Simplified and Consolidated Tutorial/Pictorial for DBV #3." Go to Post #1 of this thread and scroll down past Graph #55. Included are photos and step-by-step instructions required for preparing Rite Aid "First Aid Rolled Cotton" so it will perform like Rite Aid "Natural Absorbent Cotton." 
 
I hope this helps.

 
Ah, thank you, BMF! I'd moved away from cotton entirely for several months, but now that you've discovered a suitable way to treat readily available cotton for the purpose, I'll give it a shot. (It looks like how a pastry chef makes croissants!)
 
Jan 9, 2013 at 3:28 PM Post #317 of 2,832
FWIW, I wasn't terribly careful to make sure ALL my layers were microscopic like BMF's.. most of my layers had a 2-3 layers.. I used the slightly thicker layers to good effect. So, if you can't get the super thin layers, don't be discouraged from trying slightly thicker ones :) That cotton can be a pain.
 
Jan 10, 2013 at 8:24 PM Post #318 of 2,832
Quote:
 
Ah, thank you, BMF! I'd moved away from cotton entirely for several months, but now that you've discovered a suitable way to treat readily available cotton for the purpose, I'll give it a shot. (It looks like how a pastry chef makes croissants!)

 
Your pleasure is mine :)  
 
Prepared First Aid Cotton in this mod reminds me of baklava and sounds just as yummy.
 
Jan 16, 2013 at 11:29 AM Post #319 of 2,832
Where have the DBV#3 measurements went to? Don't see them anymore...

It seems that the main component of modding is damping the driver, that's what seems to provide flat responce. To get flat responce above 10kHz one would have to get inside the driver and damp from there, I suppose.
 
Jan 16, 2013 at 1:58 PM Post #320 of 2,832
Quote:
Where have the DBV#3 measurements went to? Don't see them anymore...

It seems that the main component of modding is damping the driver, that's what seems to provide flat responce. To get flat responce above 10kHz one would have to get inside the driver and damp from there, I suppose.

 
DBV #3 measurements didn't go anywhere because I didn't post any. DBV #3 is similar to "Dmitry's Mod" labeled DBV #2 beginning with Graph #56. My measurement mic I used for all measurements in this thread failed and I sent the Phantom Power Supply to another Head-fi'er.  The same method and equipment used by the same person is necessary to make comparable measurements.
 
I tuned DBV #3 by ear compared to a Reference Set of DBV #2. The SQ is very similar but I like DBV #3 better because of its tuning flexibility.  I can tune the treble and the bass more or less independently by altering the size of treble reflector disk and number/size of bass boost holes in the stiff craft felt; and adjusting the weight, size, and density of cotton and fiberglass.
 
Yes, months ago I came across the Russian Radical Surgery mod and was intrigued. I took apart a set of T50RP and managed to break off the side tabs of both drivers, punctured the diaphragm in one, and had a heck of a time drilling the magnets; I stopped at one driver. The magnet "filings" clumped together in interesting shapes and was pretty much impossible to remove. This turned out to be a failed mod experiment that was too labor intensive, expensive, and messy for me to want to pursue. I sent the drivers to a friend in England. 
 
Jan 16, 2013 at 5:11 PM Post #321 of 2,832
Urgh, magnet filing are the most irritating things. I've cleaned out old ortho magnets using pieces of tape and compressed air. 
 
Jan 25, 2013 at 11:53 PM Post #325 of 2,832
I´m from germany so finding double sided, removable tape was a a pain in the neck and didn´t forward any results(or they were astronimically expensive). so i´ll stick to "normal" double sided tape from "tesa" and hope i can get it off the stock white driver felt later on.
i also ordered some wool felt with 1,5mm thickness to try the 3DBV MOD.i´ve still got to go to the pharmacy for cotton, although i have some cotton pads lying around here.
 
my actual configuration is paxmate plus in the cup and plasticine in the baffle and stock pads. i recently bought a HD650 and swapped to the T50RP and had the impression that the mids were recessed or even missing so i hope the treble reflector will do its work.
 
hope i´m not in the wrong section here posting my findings?
 
Jan 26, 2013 at 9:59 AM Post #326 of 2,832
I use tesa double sided at work and I find it horrific to remove, I would not want that on my driver.
I just ordered some from the states for delivery to the uk. surprisingly cost effective.
 
Jan 26, 2013 at 12:46 PM Post #327 of 2,832

Quote:
Update: I edited and added additional information and pictures to "Simplified and Consolidated Tutorial/Pictorial for DBV #3." Go to Post #1 of this thread and scroll down past Graph #55. Included are photos and step-by-step instructions required for preparing Rite Aid "First Aid Rolled Cotton" so it will perform like Rite Aid "Natural Absorbent Cotton." 
 
I hope this helps.

 
Ahhhhh. So that's what I was missing! Definitely improves everything for me. Using unprepared London Drugs absorbent cotton and Rite-Aid first aid rolled cotton chokes off the bass and injects too much treble in my ear. But prepared stuff...now that's a different story. Thanks for this update, BMF.
 
Jan 27, 2013 at 6:33 PM Post #329 of 2,832
thx guys, i just ordered some scotch tape (removable scrap book tape) from the USA. and i got simple double sided from germany. thx for the tip, jiminy and muzo:)
 
Jan 28, 2013 at 7:55 PM Post #330 of 2,832
Someone should give Mr.Clean Magic Erasers a try. I don't have any on hand but I just stumbled across the fact that they are made from this stuff: http://en.wikipedia.org/wiki/Melamine_foam which is also sound foam. 
 

Users who are viewing this thread

Back
Top