[ruhenheiM]

there is wharfedale isodynamic available on some online auction site but the guy who sell it won't do international shipping

 

[Feilong4]

Gah, the buzzing on my T50 is back again..

Seems like it buzzes around 600 and 1000 hertz using a tone generator. Gently wiped the diaphragms again with a Q-tip and blew on it. Nothing.

Can anyone see anything potentially wrong?

 

[wazzupi]

Which orthodynamics has the best imaging and a pretty good soundstage ?

 

[GREQ]

Gah,

Can anyone see anything potentially wrong?

Hmm.... the diaphragm seems to be slightly more warped than what I've seen before.
There's a miniscule chance the diaphragm is touching the magnets at full excursion, however this is extremely unlikely... I doubt the frequencies mentioned are even able to cause a hefty excursion.

You need to look around for any debris, hair, fluff... a loose bit of foam. Even if it's around the inside of the cups or the mesh iteself, it will still resonate at the correct frequency.
Have you checked the diaphragm for holes? A tiny tear could be the cause, but also more on the unlikely side.

 

[nick n]

^ If you follow GREQ's advice ( easy stuff to do )and it still happens then.....

It could very well be the rippled area there.
Yikes the second picture shows how bad it is.
Pretty sure it should not be as floppy as that.
I wonder if it got exposed to some heat source at some point in it's lifetime.

There was a similar problem with the Fostex T50Rp Mk2 series, and there have been people popping up the odd time with the exact same issue.
In every case there the diaphragm was slightly bowed and/or warped from the factory.
This caused it to rattle /buzz but only at very low select frequencies when lots of power was thrown at it.
Notice I said slightly, so that can cause it yes )
=Look for pictures in that thread and compare.
*** Find a spot in a test track where this effect shows up and use that to check again and again. Sometimes I thought i had it fixed, then it showed up later again ..and again...

I've got a Wharfedale ID1 that bugs the heck out of me and it does the same thing.
So that one will need a full opening and figuring out how to deal with it.

In the above Fostex cases it was always necessary to transplant the diaphragms out and replace with new ones.
One showed up with that issue in the T50RP Incremental Mods Thread again very recently, and I had direct experience with one like that too.

Obviously you are not able to do a full transplant with a new thing...
I'd consider :

• Ironing it out on a perfectly flat surface with a paper(S) layer over top and below it and fast heat but that may bow up somewhere else or shrink it unevenly = DO NOT DO THIS I AM ONLY CRAZY ENOUGH FOR THAT .Hopefully this doesn't screw the traces/glue if you are fast enough or do it right.?????????????????

• Since it is generally agreed ( assuming it is held tightly/exactly in place around the entire perimeter/circumference already ) that the diaphragm is bumping the magnets to some extent at the low frequencies ( it's furthest excursion point ), the only other thing I can suggest as a longshot is to somehow try adding spacer rings on either side of the diaphragm to give it more room.

Only a tiny thickness. You don't want it losing magnetic proximity powah, Then you'd have to likely do the same to the other side to match them.

• Look in the DIY section there is a guy doing a DIY ortho drivers and all. He may have some ideas.

• look in here for warped diaphragm, tensioned vs non tensioned, diaphragm repair or similar search terms. Takato may have tried the hair dryer method but I may be mistaken ( you'd have no idea how long to do it unless it was assembled in a jig tightly and shrunk barely until the ripples disappeared, if they did at all -- or without overtightening it--or causing warpage to spread ))

• other ideas??? Anyone??

Definitely get more than a few opinions on this before even starting.

 

[GREQ]

Paper + iron probably won't work unfortunately.
Kapton's party-piece is actually it's heat resistance.

Before trying low-heat (maybe an iron that goes VERY low - low enough that you can still touch it and not get burned) I would try weight compression.
The only essential thing needed for that is fortitude, since you'll have to leave it to one side for a week without touching it and I guess the temptation to shorten the length of compression would be strong.
I would use extremely flat, extremely slick materials, maybe two sheets of glass for the direct compression. This will help prevent tensile friction while compressing and when taking off the weight.

And even then, there are no guarantees this would work. It's just an idea.

 

[nick n]

oooh yesss I forgot about the Kapton thing dammit.
My bad.
It must have had some serious heat hit it though to get that way then?

Compression it is ( i guess ) since using spacers may give some goofy sound due to it still being warped. Maybe maybe not ?

Sorry more questions than answers

 

[nick n]

ohh this may be applicable
http://www.diyaudio.com/forums/plan...luck-re-tensioning-infinity-emit-tweeter.html

kapton shown here
http://www.sciencedirect.com/science/article/pii/S0020768314001875
and something from NASA
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19800017896.pdf

 

[WallofHooligans]

I'm thinking it's either a loose diaphragm, loose foam isolation or still dirt. I'm a bit surprised that the buzzing isn't coming from a low frequency where the most excursion is happening. My bet is that the area where the diaphragm is loose is touching the yellow foam isolation. It probably only touches by a hair, and only shows up at that frequency as distortion from the added mass of foam against the kapton.

It could still be dirty. Do you dudes know what kind of cleaning solvents are safe for kapton and copper traces?

 

[nick n]

MG Chemicals Zero Residue Contact Cleaner perhaps? ( I'd have to look at the can ).

I think those may be aluminum traces(?)

GREAT point about the foam didn't think of that !

 

[Ishcabible]

There's a trick you can try to avoid overtightening the screws and stripping the threads.

But you need to use a ratcheting screwdriver.
Turn the ratcheting mechanism to the opposite direction and tighten them down until it starts to give and begins to spin, then you know you are close ( have a look ).
This usually happens right at the point where the screwhead bottoms out at the baffle top.
It's usually a careful small finger tighten after that.

I find this works on most things, but if the screwholes are a bit snug right away it might start skipping and not work this way.
Had to resort to that on the Fostex T50rp's after opening ~100 times ( no joke ) but after that point doing the reverse ratchet method worked perfectly for another 20+ openings

BMF successfully redid screwthreads with superglue I think.
I may or may not have done that also i forget.
Might have used a plastic melting solution dropped into a hole then tiny drill bit to give just enough of a hole for the screws to rebite.

That info is buried on the first post at the T50RP Incremental Mods thread.

Sorry to hear hope this works out for you.

I used some epoxy and tapped the holes which seemed to work well!

Unfortunately, from my measurements and subjective impressions, it seems like putting anything behind the driver induces ringing and I’ve gotten annoyed enough that I’m going to just cut my losses and list it on eBay before I break something. I’ll probably experiment again in the future with a less pristine-looking pair though.

 

[Feilong4]

Thanks for the suggestions!

After some looking around, I believe the problem lies with the diaphragm touching the magnets.

Just visually, the diaphragm seems to be touching the magnets. I cut out 2 rings out of paper for each side and glued it onto the plate to give a tiny bit more distance from the diaphragm and magnets.

I don't seem to be hearing any buzzing from listening to a few a sine sweeps and selects songs from which I heard the most buzzing. I had it at a fairly loud volume as well. Weird thing was that I heard buzzing during low frequencies (~50-300 hertz) today before modding, contrary to yesterday where it was just around 600 and 1000 hertz.

Here are some pics:







I might just need to go reseal the diaphragms onto the plate a little better. My soldering kinda gives a lift on the diaphragm off the plate.

Here's to hoping for no future buzzing though.

 

[nick n]

Excellent. If the paper is too thin move up to the thin cardstock

 

[Feilong4]

Anyone interested in a YH-100? The left earcup broke off from the pivot, but both sides function perfectly (which I bought that way).

I'm too lazy to figure out damping schemes and I've been buying too many things as of late haha.

Edit: Forgot to mention, I stripped two of the threads on the left earcup.

Going on classifieds in a bit.

 

[WallofHooligans]

Anyone interested in a YH-100? The left earcup broke off from the pivot, but both sides function perfectly (which I bought that way).

Oh, you're the dude that bought that pair. I have no clue as to how to repair a sheared strut. Honestly, it's probably smarter to gut the original housing and put the driver somewhere better. I'd want to put it into a Teac hp-100 perhaps