Fostex T50RP Incremental Mods and Measurements
May 15, 2013 at 12:02 PM Post #571 of 2,858
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FYI: I edited and moved all pictorials and tutorials to the bottom of Post #1. The modding guides are better organized and now easier to follow.
 
I have some additional editing to do and a few more pictures to update....eventually.

Is there a FR graph for the completed DBV #3? I never saw one... or at least not one that was noticeably labeled as such.
 
May 16, 2013 at 9:35 AM Post #572 of 2,858
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Is there a FR graph for the completed DBV #3? I never saw one... or at least not one that was noticeably labeled as such.

  The mic I used for Incremental Mods and Measurements wore out after 100's and 100's of measurements. No two mics are exactly the same due to variation in placement on the IEM triflange, alignment angle, and shape/amount of hot glue applied around the mic capsule. So, I do not have any DBV #3 graphs from the same series and with the same mic/phantom power used for DBV # 2 measurements. I can, however, say with confidence that DBV #3 would have measured similarly and sounds the same or maybe slightly better than DBV #2.
 
I've come to the conclusion that there can be about  +/- 2 dB difference across the FRs of two identically built mods but they will sound virtually the same. I've done blinded A/B listening tests with my wife serving as "examiner" and could not reliably tell which was which. Consequently, I do not spend excessive time on tuning to try and re-create a specific FR or spectrogram. I use the measurement kit to help guide me during tuning and stop when it sounds "just right" to me.
 
Bottom line: Build DBV #3 or DBV #2. They are more alike than different. DBV #3 may edge out DBV #2 depending on configuration implementation and tuning....all the usual disclaimers apply.
 
May 16, 2013 at 10:55 AM Post #573 of 2,858
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Originally Posted by bluemonkeyflyer /img/forum/go_quote.gif
 
Bottom line: Build DBV #3 or DBV #2. They are more alike than different. DBV #3 may edge out DBV #2 depending on configuration implementation and tuning....all the usual disclaimers apply.

I gotcha, I hadn't realized that the FR setup was compromised after DBV #2. I'm not concerned, really. I was just curious if you had one. I'm perfectly content with the DBV #3 and the fine tuning suggestions you have listed. I got HE-400's yesterday and it's not much of a surprise that I find my T50RP's to come out on top overall (with the exception of the clarity and open sound of the HE-400's). It's all a matter of opinion in the end anyway and since I primarily listen to EDM, the "closed" nature of the T50RP's gives the bass punch that I want. For anything that was actually recorded and not simply produced, I would rather listen to open headphones anyway.
 
May 17, 2013 at 4:18 PM Post #574 of 2,858
I want to upgrade to a V-Moda cable on mine and since I had originally planned to keep using the stock cable, I didn't seal around the jack with GE Silicon or anything. Is this the best method to do this? I guess the silicon would be easy to remove which is a huge plus. Has anyone tried bringing the jack to the surface instead of having it recessed?
 
May 18, 2013 at 10:15 AM Post #575 of 2,858
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I want to upgrade to a V-Moda cable on mine and since I had originally planned to keep using the stock cable, I didn't seal around the jack with GE Silicon or anything. Is this the best method to do this? I guess the silicon would be easy to remove which is a huge plus. Has anyone tried bringing the jack to the surface instead of having it recessed?

 
This would be extremely difficult to do with the stock jack without destroying it. I tried to remove it cleanly, and ultimately decided just to snap it off in pieces instead. It's fairly simple to bottom mount a new jack though: http://www.head-fi.org/t/452404/just-listened-to-some-fostex-t50rps-today-wow/10170#post_9447084
 
I just drilled two 1/4" holes as a test fit for now and I plan to hot glue them in securely to seal off any air gaps. 
 
May 18, 2013 at 10:40 AM Post #576 of 2,858
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This would be extremely difficult to do with the stock jack without destroying it. I tried to remove it cleanly, and ultimately decided just to snap it off in pieces instead. It's fairly simple to bottom mount a new jack though: http://www.head-fi.org/t/452404/just-listened-to-some-fostex-t50rps-today-wow/10170#post_9447084
 
I just drilled two 1/4" holes as a test fit for now and I plan to hot glue them in securely to seal off any air gaps. 

Those look sweet! I'm hoping to maintain the single entry, but mounting at the bottom isn't a bad idea...
 
May 18, 2013 at 12:40 PM Post #577 of 2,858
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This would be extremely difficult to do with the stock jack without destroying it. I tried to remove it cleanly, and ultimately decided just to snap it off in pieces instead. It's fairly simple to bottom mount a new jack though: http://www.head-fi.org/t/452404/just-listened-to-some-fostex-t50rps-today-wow/10170#post_9447084
 
I just drilled two 1/4" holes as a test fit for now and I plan to hot glue them in securely to seal off any air gaps. 

Beautiful!
 
Mind sharing your BOM?
 
May 18, 2013 at 3:57 PM Post #578 of 2,858
thx for replys:) now i´ve taken out the reflex dot and removed the scotch tape partially covering the driver grid and also removed a pinch of cotton so now they sound almost perfect.
as i said before i used 2mm natural felt and soaked it in white wood glue diluted 50/50 with water to get it stiffened and punched 6 small holes into them each.
great advice given here!
 
May 20, 2013 at 6:08 PM Post #579 of 2,858
Hey, quick question, is it okay to use sticky felt like this?
 
http://www.amazon.com/Darice-FLT-0499-Felties-Sticky-Primary/dp/B004N5L1ZQ
 
My guess would be no, but just wondering as it'd be more convenient than the felt+tape combo.
 
May 20, 2013 at 6:13 PM Post #580 of 2,858
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Hey, quick question, is it okay to use sticky felt like this?
 
http://www.amazon.com/Darice-FLT-0499-Felties-Sticky-Primary/dp/B004N5L1ZQ
 
My guess would be no, but just wondering as it'd be more convenient than the felt+tape combo.

I don't think you want the adhesive over the drivers but this would work well for the adhesive felt on the cup floors.
 
May 20, 2013 at 6:41 PM Post #581 of 2,858
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Hey, quick question, is it okay to use sticky felt like this?
 
http://www.amazon.com/Darice-FLT-0499-Felties-Sticky-Primary/dp/B004N5L1ZQ
 
My guess would be no, but just wondering as it'd be more convenient than the felt+tape combo.

FWIW/IME, don't put any adhesive (self-adhesive felt, tape, etc.) directly on the white driver damping material. Use removable, acid-free double sided tape around the driver frames to secure non-adhesive felt, etc. to the drivers. Adhesive applied to the back of the driver may react with the damping material and alter the sound. I had one set's white damping material disintegrate and turn to goo. Adhesive will also totally damp/choke the driver.
 
I've not had good results with self-adhesive felt in the cups as the only sound absorber...it's too thin and I can't tell that it does much, if anything. Paxmate and Silverstone work better for me in the cups and in/on the baffles (both sides).
 
May 20, 2013 at 9:55 PM Post #584 of 2,858
Anybody have any idea what I can do to reduce the response in the 125-500hz area? Other than this area I'm actually happy with my T50rp. Please don't say "modified bass port", because I have already messed with that and currently have just a tiny pen tip sized hole poked in each side. The bass from 100hz and down is plentiful, but from about 125 to 500hz is bloated and muddy. Eq'ing out 1.5db at 125, 3db at 250 and 1.5db at 500hz makes them sound spectacular, but I'd like to do this without EQ if possible.
 
May 20, 2013 at 9:56 PM Post #585 of 2,858
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Thanks for the replies. I kind of figured as much since I'm sure BMF would have mentioned it, but you never know.

Many roads lead to the same destination. You never know 'til you go.
 
Best wishes.
 

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