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

[micmacmo]

mrspeakers, how do you account for the difference b/n the FR curves and the cascades? Specifically, I'm thinking about the 3-5K dip in the cascades that isn't present in the FR curves. 

 

[mrspeakers]

The cascades are a narrower frequency range than the linear plot because bass waterfalls obscure mid and high details.  Because of this the waveform looks quite different.  Also, the vertical scale is exaggerated in the waterfall, which makes the peaks and troughs look considerably different than they do on the full range plot.

 

[micmacmo]

I see what you mean. I didn't pay attention to the graph's scales. Thanks. 

 

[theguatemalian]

Just finished modding my T50RPs to a config similar to the BMF 6 v2 (Light), it sounds good but something is wrong something is fatiguing my ears but I'm not sure how to go about figuring out what it is 

.
 
I put about 10 grams of plasticine in each baffle dimpled, put dynamat strips in the sides of the cup and covered that and the 1 inch rectangle with SIlverstone Acoustic Foam, as well as the top of the Pillar thing. Dynamat around the driver earside ( I have no adhesive felt could this be messing it up?), and Gauze under the the posterior part of the pads.
 
 
 
Also these headphones grip right on my jaw muscle and joint it's a bother bother any way to fix that?
 
In any case amazing change the sound from stock which I decided to stick to  for a few days to be able to notice the difference, keep up the good work guys, I'm gonna keep tweaking! 
 
 
Edit: Woooo not a Junior Head-Fier anymore!

 

[leeperry]

Awesome research there, thanks for posting!

Well, we all aim at the same goal! Anyways, I've gotten a hold of him and I've got a sample of C5g heading my way. The good news is what he just told me: "The density of C5g  is about 1.8 g/mL, so considerably less than tungsten putty! And C5g works by frictional losses (converting vibrations to low amounts of heat) so mass is not an issue. A layer (without screwdriver holes) up to several mm thick is all that is necessary for your application, I would guess"
 
So I can see a bright future in only a few mm of C5g in the baffles and acoustipak foam in both the baffles and cups, better SQ and very light to boot

 

[bluemonkeyflyer]

Fatiguing in what way/frequency range? In the absence of felt, you could try one or two layers of gauze over the ear side Dynamat. Maybe try a different source or amp? Are the bass ports unblocked with the black felt in place? You could carefully remove the black felt over the bass ports and tune from the outside with electrical tape over some of the vent slots. If that does not help, you can put them back with rubber cement.

Probably unrelated but did you remove the dust cover felt surrounding the drivers on the ear side before applying the Dynamat? Is the dust cover still over the driver on the ear side?

Counter intuitive but you could try removing the silverstone over the central compartment (pillar).

The Dynamat on the sides of the central section at the bottom of the cups and beneath the silverstone probably adds nothing. You could take it out and put the silverstone back in place.

I have no fatigue but our ears may be different. Good luck tweaking.

Just finished modding my T50RPs to a config similar to the BMF 6 v2 (Light), it sounds good but something is wrong something is fatiguing my ears but I'm not sure how to go about figuring out what it is 

.
 
I put about 10 grams of plasticine in each baffle dimpled, put dynamat strips in the sides of the cup and covered that and the 1 inch rectangle with SIlverstone Acoustic Foam, as well as the top of the Pillar thing. Dynamat around the driver earside ( I have no adhesive felt could this be messing it up?), and Gauze under the the posterior part of the pads.
 
 
 
Also these headphones grip right on my jaw muscle and joint it's a bother bother any way to fix that?
 
In any case amazing change the sound from stock which I decided to stick to  for a few days to be able to notice the difference, keep up the good work guys, I'm gonna keep tweaking! 
 
 
Edit: Woooo not a Junior Head-Fier anymore!

 

[drez]

Drat, looks like I ordered some weird siliconous rubber sheet instead of speaker felt DX".  No idea what this stuff is used for - invoice says "rubber feet" but the sheet isn't even thickness...
looks like I will need to place another order, but I recon this paxmate should do very well in meantime.
I think from memory felt damping might act differently to paxmate as it presents a greater surface area to the driver.  I never did take that speaker design course (maybe there is an ebook?)
Needs more solder for b22 anyways, also need to order "electronics for dummies" as fail insurance.

 

[Armaegis]

If only this weren't so expensive, it'd be one of the few times I'd actually want to buy a textbook... 
http://www.amazon.com/Loudspeaker-Headphone-Handbook-Third-Borwick/dp/0240515781/ref=sr_1_1?ie=UTF8&qid=1319598767&sr=8-1

 

[theguatemalian]

Just quick modded a thick layer (4mm) of gauze onto the dynamat foil and it fixed my problem it was the vocals and the guitars that were too shirll and harsh but the gauze atenuated it to a very pleasing noise. I guess maybe I was getting harsh reflections off the foil on the dyanamat.
 
Thanks fo the tip!

 

[mrspeakers]

Quote:

If only this weren't so expensive, it'd be one of the few times I'd actually want to buy a textbook... 
http://www.amazon.com/Loudspeaker-Headphone-Handbook-Third-Borwick/dp/0240515781/ref=sr_1_1?ie=UTF8&qid=1319598767&sr=8-1

While not specific to headphones, most of the high-level concepts are relevant and the price is way lower.  I refer aspiring speaker designers to this all the time.  It's best if you are technically comfortable through math/science.  
 
http://www.amazon.com/Loudspeaker-Design-Cookbook-Vance-Dickason/dp/1882580478/ref=pd_sim_b_4
 
 

 

[dogears]

Augh! No more posts like this please... It gives me the itch 

Quote:

5. soundwise for me, he500 > lcd-2 > th900
 


 

 

 

[JadeEast]

Mr.Speaker those graphs (and the gumption to set up the rig) are awesome. Any chance for a measurements of a single variable in the tuning of the Fostex or a pre/post mod comparison? 
 

 

[JadeEast]

Quote:

If only this weren't so expensive, it'd be one of the few times I'd actually want to buy a textbook... 
http://www.amazon.com/Loudspeaker-Headphone-Handbook-Third-Borwick/dp/0240515781/ref=sr_1_1?ie=UTF8&qid=1319598767&sr=8-1

That book is insane and it may be in your local library. You can get a taste of it on Google books. Check page 598. 
http://books.google.com/books?id=9DeZqnsjetgC&pg=PA585&source=gbs_toc_r&cad=4#v=onepage&q&f=false

 

[drexman]

what's better, micropore or transpore on the back of the driver?

 

[HDMan]

How do the modded T50RP's stack up against the Stax range, anybody got both?