Twinster
Headphoneus Supremus
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Just listened to some Fostex T50RPs today... WOW!
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micmacmo
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Quote:
LFF has since updated it, but here's the gist:
http://www.head-fi.org/t/452404/just-listened-to-some-fostex-t50rps-today-wow/2895#post_7782196
wdahm519
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Has any actually had a successful attempt at an open-mod of these yet? Or has anyone just listened to them with the back ear up off? I'd be really pumped to do a mesh grill open-back mod and make these super flat.
I've been building a test capability so I can quantify my designs.
Here is the frequency response of the Rastapants with the O2 pads (IMPORTANT NOTE: The RP2 tested here has two mods from what I published: about 6-7 cotton balls/wool in each cup and the vent 50% closed. These mods make a nice and easy upgrade, and work for the 840 pads, as well. The 840 testing with the same RP2 setup indicates that 75-85% closed works pretty well, though I'm not done). I validated the above results through multiple tests, which were actually quite consistent, and averaged 10 plots to generate these charts.
Here is the frequency response of the LCD 2:
A few notes:
1) These tests are on a flat baffle, which is not going to give the same curves as a "ear" or "head" measurement system. In other words, they will look different from the test Tyll publishes, and they'll also be different what Purrin measures because his rig is somewhat different, as is his software. The key thing to understand with headphone testing is that one testers charts can really only meaningfully be compared to more charts BY THAT TESTER. And they should be seen as RELATIVE but not ABSOLUTE, as there are so many variables that affect results. Tyll has written a ton of great stuff on why that is (and knows more than I do on this) so I won't repeat it...
2) The bass measurement is more accurate than mids/highs due to wavelengths so take high frequency results as a general indicator of response curve SHAPE, but not exactly what you'll hear (again, see Tylls blogs). For example, my suspicion is that the deep notch at 4.5K on the LCD2 is probably a standing wave rather than a real hole in their frequency response, so don't go dissin' those cans because of it.
Results:
The LCD2 has deeper extension below 30Hz. The bump of the RP2 gives it a bit more bass slam and weight, sort of like the JH16 sound, which actually really is fun to listen to, and does not sound "boomy," but not as "absolutely accurate" as I'd like. I'd like to flatten the bass out a bit more and get a few more Hz out at the bottom. It's not "too much of a good thing." The sound, as you'd probably expect from the spectral tilt, is a bit warmer than the LCD2, though and the highs feel brighter. I'd characterize the RP2 as sounding "bigger" than the LCD2, with a better defined top-end, but a bit less extension and linearity at the bottom.
The RP2 has a notch from 3-5KHz that pulls the upper mids back a bit. It's not objectionably obvious like a big spike in frequency response, but it will liven up the sound even further to address this, so I'll be giving it my best shot.
I did do some waterfall plots but won't publish until I'm more confident in my testing skills. I will say they validated one area that made me prefer the Rastapants 2; it has SUPER fast decay above 1.5K and less ringing than the LCD2 I tested. And the LCD2 decay is excellent.
Again, I wouldn't say this is absolute, I'm still learning my test rig setup, but it did validate one of the things I really like about the RP2. It's possible the difference is how I tested vs. what I tested, if you follow, so for this reason, I don't want to publish the waterfalls until I am more confident I'm testing accurately.
Thanks to Tyll and Purrin for some inspiration, ideas and direct input on testing. My next post on mods will either be doing a fully reversible design or further optimizations on the Rastapants 2 to smooth those to areas of interest out.
Here is the frequency response of the Rastapants with the O2 pads (IMPORTANT NOTE: The RP2 tested here has two mods from what I published: about 6-7 cotton balls/wool in each cup and the vent 50% closed. These mods make a nice and easy upgrade, and work for the 840 pads, as well. The 840 testing with the same RP2 setup indicates that 75-85% closed works pretty well, though I'm not done). I validated the above results through multiple tests, which were actually quite consistent, and averaged 10 plots to generate these charts.
Here is the frequency response of the LCD 2:
A few notes:
1) These tests are on a flat baffle, which is not going to give the same curves as a "ear" or "head" measurement system. In other words, they will look different from the test Tyll publishes, and they'll also be different what Purrin measures because his rig is somewhat different, as is his software. The key thing to understand with headphone testing is that one testers charts can really only meaningfully be compared to more charts BY THAT TESTER. And they should be seen as RELATIVE but not ABSOLUTE, as there are so many variables that affect results. Tyll has written a ton of great stuff on why that is (and knows more than I do on this) so I won't repeat it...
2) The bass measurement is more accurate than mids/highs due to wavelengths so take high frequency results as a general indicator of response curve SHAPE, but not exactly what you'll hear (again, see Tylls blogs). For example, my suspicion is that the deep notch at 4.5K on the LCD2 is probably a standing wave rather than a real hole in their frequency response, so don't go dissin' those cans because of it.
Results:
The LCD2 has deeper extension below 30Hz. The bump of the RP2 gives it a bit more bass slam and weight, sort of like the JH16 sound, which actually really is fun to listen to, and does not sound "boomy," but not as "absolutely accurate" as I'd like. I'd like to flatten the bass out a bit more and get a few more Hz out at the bottom. It's not "too much of a good thing." The sound, as you'd probably expect from the spectral tilt, is a bit warmer than the LCD2, though and the highs feel brighter. I'd characterize the RP2 as sounding "bigger" than the LCD2, with a better defined top-end, but a bit less extension and linearity at the bottom.
The RP2 has a notch from 3-5KHz that pulls the upper mids back a bit. It's not objectionably obvious like a big spike in frequency response, but it will liven up the sound even further to address this, so I'll be giving it my best shot.
I did do some waterfall plots but won't publish until I'm more confident in my testing skills. I will say they validated one area that made me prefer the Rastapants 2; it has SUPER fast decay above 1.5K and less ringing than the LCD2 I tested. And the LCD2 decay is excellent.
Again, I wouldn't say this is absolute, I'm still learning my test rig setup, but it did validate one of the things I really like about the RP2. It's possible the difference is how I tested vs. what I tested, if you follow, so for this reason, I don't want to publish the waterfalls until I am more confident I'm testing accurately.
Thanks to Tyll and Purrin for some inspiration, ideas and direct input on testing. My next post on mods will either be doing a fully reversible design or further optimizations on the Rastapants 2 to smooth those to areas of interest out.
Quote:
It was tried and reported to have pretty bad results, but that doesn't mean someone else shouldn't try. I will say that as the performance varies hugely based on the venting on the cups, it's probably a foregone conclusion having the driver totally open on one sound will sound pretty bad. The driver was designed to have a semi-closed/closed enclosure, probably to balance out the air-mass on both sides of the driver to maximize linearity.
CYoung234
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Quote:
Just an update. Switching to Shure 840 pads with the last mods I did really helped the high end to get where I needed it. I think I am done for now (except for making one more pair for my twin brother to try out! I will likely not use as much Dynamat in this pair, but may try a layer of it on the ear side.
wdahm519
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Quote:
You're correct, I do remember now that I think back on it. I'll have to try your cottonball idea. Did you have nothing except for cotton balls and venting for those measurements?
mmayer167
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@ mrspeakers - how do you fit 6-7 cotton balls in each cup? If I had nothing in my cup to start with I could maybe squeeze 4 in there... how big are you balls?
I agree with your "fun" sound analogy with the RP2. I am running a-lot of clay near the driver tapered out to just filling the baffle tray at the rim. paxmate in the back of the cup and up the short sides but not on the curved areas. Lastly 2 jumbo cotton balls in the cup covering the factory reflex dot/screw port area and leaving a hole open in the cotton for the bass vents which are 50% covered. This setup is the most articulate and detailed with treb extension, while still remaining fun in the bottom end with loads of tight hard hitting fast bass "that I have tried". I will enjoy this fun sound for a while as a rest stop along the journey to find the neutie can i'm searching, I hope I can find it! ps: i'm using the o2 pads, they are sort of a round peg square hole deal though being that the t50 is oval and the o2 is round... hard to get a good seal imo.
Have fun with your new test setup and we're with you here through your triumphs and failures
M
I agree with your "fun" sound analogy with the RP2. I am running a-lot of clay near the driver tapered out to just filling the baffle tray at the rim. paxmate in the back of the cup and up the short sides but not on the curved areas. Lastly 2 jumbo cotton balls in the cup covering the factory reflex dot/screw port area and leaving a hole open in the cotton for the bass vents which are 50% covered. This setup is the most articulate and detailed with treb extension, while still remaining fun in the bottom end with loads of tight hard hitting fast bass "that I have tried". I will enjoy this fun sound for a while as a rest stop along the journey to find the neutie can i'm searching, I hope I can find it! ps: i'm using the o2 pads, they are sort of a round peg square hole deal though being that the t50 is oval and the o2 is round... hard to get a good seal imo.
Have fun with your new test setup and we're with you here through your triumphs and failures
M
Quote:
@ mrspeakers - how do you fit 6-7 cotton balls in each cup? If I had nothing in my cup to start with I could maybe squeeze 4 in there... how big are you balls?
I agree with your "fun" sound analogy with the RP2. I am running a-lot of clay near the driver tapered out to just filling the baffle tray at the rim. paxmate in the back of the cup and up the short sides but not on the curved areas. Lastly 2 jumbo cotton balls in the cup covering the factory reflex dot/screw port area and leaving a hole open in the cotton for the bass vents which are 50% covered. This setup is the most articulate and detailed with treb extension, while still remaining fun in the bottom end with loads of tight hard hitting fast bass "that I have tried". I will enjoy this fun sound for a while as a rest stop along the journey to find the neutie can i'm searching, I hope I can find it! ps: i'm using the o2 pads, they are sort of a round peg square hole deal though being that the t50 is oval and the o2 is round... hard to get a good seal imo.
Have fun with your new test setup and we're with you here through your triumphs and failures
M
I used "regular" balls. My balls clearly aren't as big as yours.
Quote:
The configuration was a full Rastapants 2 with O2 pads, and the two mods I mentioned.
mmayer167
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I guess so, I think regular balls might be easier to play with...
Too far, my bad.
back to the grind.
M
edit: i hope my girlfriend never finds this post!
Too far, my bad.
back to the grind.
M
edit: i hope my girlfriend never finds this post!
Hennyo
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Wow, really great looking plots. Acutally looks kind of like hd 650. (The fr that is, only it's Mach (2) faster and again, 'SUPER' shiny fast above that 1.5kish).
Any chance Purrin's going to post the fr's to the paradox and rp2? Dying to see them. ; ) Thanks for the hard work, and we're enjoying observing your experience with these cans. Bmf and all others, you too.
Any chance Purrin's going to post the fr's to the paradox and rp2? Dying to see them. ; ) Thanks for the hard work, and we're enjoying observing your experience with these cans. Bmf and all others, you too.
hans030390
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Quote:
When I modded my D2000s into open-backed headphones, I found that I had to raise the earpads off the frame of the headphone to get them to sound good. For those of you that aren't familiar with the D2000/5000/7000, the earpads have 4 plastic pegs on the bottom of them that are used to lock the earpads onto the frame of the headphone. Instead of locking them in, I instead rest those plastic pegs on the frame itself. In that aspect, they offset the earpads from the frame and provide airflow underneath the pads. If you didn't do that, they sounded pretty awful as open headphones.
Now, that said, I am NOT saying this will necessarily work for the T50RPs...but it might be something worth playing around with?
When I modded my D2000s into open-backed headphones, I found that I had to raise the earpads off the frame of the headphone to get them to sound good. For those of you that aren't familiar with the D2000/5000/7000, the earpads have 4 plastic pegs on the bottom of them that are used to lock the earpads onto the frame of the headphone. Instead of locking them in, I instead rest those plastic pegs on the frame itself. In that aspect, they offset the earpads from the frame and provide airflow underneath the pads. If you didn't do that, they sounded pretty awful as open headphones.
Now, that said, I am NOT saying this will necessarily work for the T50RPs...but it might be something worth playing around with?
Quote:
Purrin had a plot of a version I thought might be 2.1 but his tests showed me a couple of pretty poor areas, so I decided I needed to get equipped... His plot wouldn't look anything like the RP2 or this version...
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