Just listened to some Fostex T50RPs today... WOW!

[deadhead12]

So I've had these for a couple of days and the presentation seems a bit weird to me.  It's like there is an invisible wall/barrier starting at my forehead and no sound can go forward past that point.  Theres a side to side, up and down, and back but no frontward presentation.  Is this normal?  So far, I've used dynamat in the cups and blutack in the baffle and I've taken off the stock felt on the front of the driver so it's naked with the dust cover still on it.  I'm also using ad700 pads over top of the stock pads but I tested with just the stock pads and it's the same presentation.  I really don't think anything I've done could cause this but I really don't know.  
 
Maybe I've just gotten used to the presentation of my dt880's but idk.  Everything else is great though, although I'd like just a tad more bass.  I've got plans to try different felt etc, but I'm puzzled by the presentation.    
 

 

[maverickronin]

IME the Akasa will widen the soundstage and clean up the imaging a little while angling the pads will add more depth to the soundstage.  
 
All that really depends on what else you've done to them.

 

[deadhead12]

Akasa is on my list of things to try but I'm still worried about the massive gap in front of me.  The soundstage is like a pacman with the mouth facing forward.  I'm not sure that angling the pads will fill in that gap, but I won't rule it out either.   
 
Do you happen to have a pattern for the pads you made?  I'd rather try to make my own as opposed to shelling out for the sa5k or O2 pads.  
 
Edit: Is akasa paxmate the same thing as dynaliner?  

 

[maverickronin]

Here's a picture of my patterns with the relevant measurements overlaid.  The picture is taken at an angle so the flash doesn't bounce straight back up into the lens so the proportions look a little off.  Just ignore it and go by the measurements.

 

[Mad Max]

 
Quote:

Akasa is on my list of things to try but I'm still worried about the massive gap in front of me.  The soundstage is like a pacman with the mouth facing forward.  I'm not sure that angling the pads will fill in that gap, but I won't rule it out either.   
 
Do you happen to have a pattern for the pads you made?  I'd rather try to make my own as opposed to shelling out for the sa5k or O2 pads.  
 
Edit: Is akasa paxmate the same thing as dynaliner?  

To remove the gap in the soundstage, remove the felt covering the bottom vent in each cup.  Those drivers need to breath!  Totally reversible.
 
Paxmate is acoustic foam of sorts.  Dynamat is a type of putty with aluminum foil.
 

 

[mrspeakers]

I had very bad results in my config opening the vent, the midbass became horribly bloated and the bottom disappeared, and the midrange was totally sucked out.  However, I have replaced the stock fabric on the back of the driver with transpore and micropore, so it's entirely probable this affected the bass damping.  I will experiment with felt instead of tape this weekend, just for giggles.

 

[deadhead12]

Quote:

 

To remove the gap in the soundstage, remove the felt covering the bottom vent in each cup.  Those drivers need to breath!  Totally reversible.
 
Paxmate is acoustic foam of sorts.  Dynamat is a type of putty with aluminum foil.
 

no, I mean dynaliner, not dynamat.
 


Quote:

Here's a picture of my patterns with the relevant measurements overlaid.  The picture is taken at an angle so the flash doesn't bounce straight back up into the lens so the proportions look a little off.  Just ignore it and go by the measurements.

Thanks, I'll see what I come up with. 
 
 

 

[joelpearce]

Quote:

no, I mean dynaliner, not dynamat.
 
 

So, closed-cell foam that's designed to block outside noise?  I'm not sure that's going to help with either issue.  Because it's closed-cell, it won't absorb sound, but it's also meant as an acoustic addition to Dynamat, so it's also not designed to absorb vibration.

 

[VulgarDisplay]

Quote:

I had very bad results in my config opening the vent, the midbass became horribly bloated and the bottom disappeared, and the midrange was totally sucked out.  However, I have replaced the stock fabric on the back of the driver with transpore and micropore, so it's entirely probable this affected the bass damping.  I will experiment with felt instead of tape this weekend, just for giggles.

I for one though that removing the stock damping from the back of the drivers and doing the transpore/micropore pattern ruined the sound, so I just covered the backs with micropore because it was similar to the stock damping.  
 

 

[kwkarth]

Quote:

OK then.  I think I'm closing in on a solution.  I think its a bit of both the power issue and the cup reflection issue.
 
Power Issue:  I'm running my signal through my Bithead for the crossfeed processing and into my stronger Maverick D1 for final amplification and the soundstage is much better, but not quite where I want it because of the the...
 
Reflection Issue:  The mids sound like they're originating  from outside the cups but the highs, especially cymbals, feel very inside the cups.  I think this is because all the treble is reflection off the dynamat I've lined the back of the cups with despite all the felt inbetween, which is a shame, since the dynamat did wonders for the mids and bass.  I'm hoping that the Akasa will be the solution to this problem.
 
I'm also thinking that the XM6 might be a good solution to the power and soundstaging issues.  Its got adjustable active crossfeed and rollable opamps and output buffers with over a watt of output power.  It might make a good amp for both home and portable use which would let me sell off some gear and consolidate.

Turn the crossfeed off.
 
 

 

[deadhead12]

Quote:

So, closed-cell foam that's designed to block outside noise?  I'm not sure that's going to help with either issue.  Because it's closed-cell, it won't absorb sound, but it's also meant as an acoustic addition to Dynamat, so it's also not designed to absorb vibration.

ok fair enough.  I just wasn't sure what the difference was.  
 

 

[maverickronin]

Quote:

Turn the crossfeed off.
 

That's old news now.  The Akasa fixed it and the soundstage is awesome now.  Turning the crossfeed off didn't change that before I put the Akasa in anyway.  
 
Even if that would fix it I'd have to ditch them or live with it anyway since most headphones give me a headache if I don't use crossfeed.  Thanks for the suggestion though.

 

[leeperry]

 

most headphones give me a headache if I don't use crossfeed.

 
Same here, and the T50RP has a very wide center channel that really need to be filled IME.

 

[kwkarth]

Quote:

That's old news now.  The Akasa fixed it and the soundstage is awesome now.  Turning the crossfeed off didn't change that before I put the Akasa in anyway.  
 
Even if that would fix it I'd have to ditch them or live with it anyway since most headphones give me a headache if I don't use crossfeed.  Thanks for the suggestion though.

The need for, and benefit from crossfeed will vary with the recording you're listening to. It's never an all or nothing issue with crossfeed.
 

 

[leeperry]

I humbly believe that it boils down to the xfeed implementation...most of them sound wonky to the utmost(eg. the Meier Audio "mono-izer"). This one works best for me, it fills the center but I couldn't even DBT it...it simply provides a very subtle xfeed to make your brain happy, nothing more: http://vellocet.com/software/VNoPhones.html