[avid2010]

I dismantled the HP50a and gave it a good scrub with the toothbrush. I resoldered the drivers into a 'stereo' configuration and gave it some damping with the craft felt I found in a shop.
 
I don't know if it is the bass lite version as some mentioned in some posts, I can hear the bass going deep but the levels are not that loud, the vocals are really up front. I am wondering if there is a damping scheme that can bring the bass section a 'little louder'.
 
Right now with only craft felt on hand, I have it balanced with 'just enough' trebles and bass, if I put more damping, the bass tightens up and loses some presence and the treble becomes sharper. If I reduce the damping, the treble hides behind the lows and the mids and sounds a little 'veil', the bass doesn't really go louder but it has more presence and is looser.
 
I have tried using the thick white damping material found in the hd25 and the sound cleared up and the trebles really stood out and the bass tighten up but became softer.
 
I bought a few different colored craft felts,they had different levels of thickness and coarseness. In reality I think they are the same, just that each color had different degree of treatment in their manufacture. The black color is really thin and compressed, it is almost 'shiny' and hard as in it could stand up vertically without collapsing, while the other colors have varying degrees of thickness and roughness but not as compress and are quite limp and soft.
 
Between the thinner, harder and more compressed craft felt and the thicker, softer and less compressed felt, is there a difference to damping of the 'sound waves' or do they essentially have the same properties?
 
I also put bluetack on the driver/baffle edge to seal the gap.
 
Any thoughts as to how I can improve on the hp50a? Thanks.
 

 

[avid2010]

These are the craft felt I bought. From the left is the denser more compressed black felt and to the right is the less dense blue felt. The second photo shows the amount of light passing through.
 
I read from the posts that natural felt with wool is better then synthetic (the craft felt?), is it 'a lot' better for damping or is it a smaller percentage in your opinion?
 

 

[gurubhai]

If you want to increase the bass, then you can start by dampening the rear vents.
 
Thicker & denser felts would damp harder, try & find one which works for you.

 

[rhythmdevils]

Where did the white (paper?) discs go in stock form?  I don't remember seeing those in my HP-50. 

 

[avid2010]

The white disc [some kind of fibre glass type material? I was able to wash and dry them ] is in-between the stock greyish black disc and the driver.
 
Would it be right to say that if I damp or try to block/seal the vents, I will get stronger bass? Sounds like a plan. The headphones is currently 'leaking' a lot of sound.

 

[rhythmdevils]

Between your ear and the driver?

 

[avid2010]

Yup, in the order of :
 
earpad, baffle, greyish black disc, white disc and then the driver..

 

[avid2010]

What do you think of these felts? Are they feasible for damping?
 
http://www.bandmfelt.com.au/products/3mm-felt
 
http://www.feltshop.com.au/product.asp?pID=57&cID=1
 
http://www.cagroup.com.au/Malthoid.asp

 

[bluemonkeyflyer]

PM your address to me for Paxmate Plus.  I gave away most of my first order but have a piece left over I can send you.  I got it at Performance PCS dot com.  The fiberglass was sent to me by Smeggy as part of a "full TP1 kit" so I will need to keep that for my T50RP transplant.  I don't know where he gets it.
 
Quote:

Have you tried wool felt?  Even the bass heavy RP18 can be tuned to be fairly basslite with enough dense felt.  But the felt does affect other frequencies as well, so it's kind of a balancing act.  But if you're only using fiberglass now, you might want to try felt against the driver or in the back of the cups.  You could also try another bass port which you could plug up if it sounds bad, but have around for tuning options. You could also open more vents venting backwave into the ear chamber...
 
Where did you get the fiberglass and paxmate?  If you're in the states, I'd be interested in trading you for some nice wool felt.  I've never tried either of those. 

 

 

[bluemonkeyflyer]

Quote:

 
Eh? we thought you had the SFI installed in the headphone already with a donut of felt on the ear side.
 
As for which side should be facing the ear, I'm guessing you're correct in your guess.
 
 

I did not install a felt donut on the ear side or any felt on the rear side of the SFI drivers.  I will try felt on the rear side, next.  I re-read Stacy's aka Germania's "Does It Pew" and will try some of her dampening schemes. So far, though, I have not drilled any holes in the wood cups; that will come last if other mods fail to tune-out the 250 hz hump. I'll also add a reflex dot.  Stacy mentioned that the ear side of the SFI's is the one with the smooth, fine mesh which is the way I installed them.
 

 

[dBel84]

This is what we commonly refer to as the paper disc - several of the yamaha's had this placed in front of the driver - iirc, all my HP50's have had this, possibly the yhd2  - i forget. 
 
My advice would be to get rid of it - not in front nor at the back. Damping is obviously listener dependent but simple is better for the HP50 - cover the back of the cup with felt ( dense ) stock foam (if not crumbling) in between, dial it in or out with variable disc / donut against the driver. In mine I even removed the stock foam and used a denser donut of felt behind the driver - this allows the holes around the center pin to be free in air while the outer holes are damped pretty heavily. The major thing for me was to damp the rear of the cup well  -  I have dense but thin cashmere "felt" 
 
To see how well this works, read Tyll's comments and see measurements
 
..dB

 

[avid2010]

dBel84, based on several posts in the thread plus what you just mentioned, it would seem that the damping scheme is 'segmented' into different 'zones':
 
1. There is the 'rear of the cup zone' where most of you would place very dense materials to cover the vent. Would it be correct to say that by blocking/sealing the vents, this process will bring out the bass?
 
2. The 'next to the driver zone' where a dense donut of varying size would be placed to further shape the sound. I am wondering what role the damping material closest to the driver does..
 
3. The stock foam is 'the partition' between the two zones above?
 
4. The cotton wool was also recommended in previous posts to be placed in the ball socket. (I tried this and the treble was diminished, so in my situation the cotton wool has to be remove to allow reflection for the trebles)

 

[Kabeer]

Does anyone have a yamaha HP-1 or YH-1 frame they arent using?
Maybe one from project where you put the drivers into another frame or something?
 
Thanks

 

[Armaegis]

I know a guy with an HP-3 frame...

 

[rhythmdevils]

Avid, I think you've got the general idea.  driver-felt-foam-felt-cups is a popular ordering.  But people do things different ways and it depends on what materials you're using.  I don't personally think you need to damp the cup openings for bass, leaving them open helps soundstage.  But YMMV