[nick n]

So are you going to use those as a transplant then if so which driver?
 
I just finished off the Alder woodies with the new shallower pads, sealed around the rim of the SFI with thin layer of putty, added another disc of the superdense whitish felt so 2 total. Still a bit of a tapered airspace directly behind the back of the driver. I didn't "cone" the smaller recess at the very backs of the cups because I realized they were convexed from the tip of the smaller drillbit already, rather than being flat pits. They are not filled, as the discs of dampening felt sit level just above them. They're maybe 1/4" deep.
Used some black scavenged transparent speaker grille fabric for inside the pads to cover the drivers and make it look top notch.
 I notice that the bass heavy tracks no longer seem to cause the driver to rattle slightly. I thought they were tight before but suppose not.
 
I wish you luck on the Maruni/Prefer search.
 

 

[wualta]

 
Quote:

So are you going to use those as a transplant then if so which driver?

Welll, ya knowww... I do have an orphan set of YHD-2 drivers...  But I have to open the fake vents on the back of the cup. Since I don't have a Dremel-type tool (maybe I should buy one!), I'm thinking of some low-rent lo-tech ways of doing it. I'm thinking hot nails, vise grips, open flame.
 
Oh-- Mario Bellini has had his minions working overtime on his website. It's pretty slick. And it's worth checking it out, since a WhoBay seller is claiming Bellini designed the Triumph TR-7!   http://www.bellini.it/
 

 

[funch]

Update on the Plastic Pantz: polished cups. (Please excuse the dust.)
 

 

 

 
Final finish sanding was done wet. First, a medium/fine sanding sponge, then #220, #320, #600,
then the final polishing was done with a Dremel using their polishing compound (jewelers rouge).
The coloration is somewhat blotchey (it's ABS plumbing after all), but I'm happy with the results.
 
I drilled a second smaller set of bass ports (the larger ones are 1/8", the smaller are 3/32").
Next task is to figure out a way to switch between the two on the fly.

 

[dBel84]

I have to say, that is just mind bogglingly fantastic. I need to pay the local ACE a visit as my carpentry skills will never be what I would like them to be..dB

 

[yipcanjo]

That is freakin' awesome, Funch!  You continue to impress....

 

[nick n]

Hard to believe that's actually plastic!
I may use the polishing idea on some stuff I have on the go, quite a bit different than those beauties.
 
One thing I was wondering about , is a sensation I have been getting from the SFI cans I put together. Each have bass ports reasonable sized ones on this I am listening to now, and I have been getting what can only be described as a rumble effect from the drivers periodically and song dependent, but it's a physical sensation that I feel more than hear from the driver. Now that I notice it, the drivers themselves also have a tactile sound and this effect must be at the extreme  of it (?) The rumble effect is definitely not a loose driver type of thing, not a chance with this mod. It is very  momentary must be in time with certain notes. Volume levels are not excessive.
Now I'm just rambling again.
Anyone know what I mean? It's not extreme but enough to feel slightly.
 What would cause this? Drivers working themselves in?
 Curious.
It's definitely interesting.

 

[Armaegis]

My best guess would be that you're hitting a resonant frequency just below the audible range. If you know when in the song you're hitting it, try using your hands to apply pressure to the cups (either pressing onto your head or simply squeezing) which should in theory lower the fundamental frequency. If it's not that, it might be something just on the baffle plate, or maybe something else entirely. 

 

[nick n]

I'll give that a shot, pressing. On both cans, the bass heavier one moreso. This set has the driver embedded and secured tightly in it's baffle housing in a ginormous mass of putty and plenty of felt damping layers of which the layers lining the cup are bonded to the housing walls. See what I can figure out thanks for the advice.

 

[wualta]

 
Quote:

Originally Posted by nick n /img/forum/go_quote.gif
 
 I have been getting what can only be described as a rumble effect from the drivers periodically and song dependent, but it's a physical sensation that I feel more than hear from the driver.
 
Now I'm just rambling again.

Nah, just rumbling again. Keep watching for correlated stuff, like : only with this amp, only with this song, only when  the line voltage drops to 85, only after eating certain Indian spices, etc.
 

 
Quote:

I'll give that a shot, pressing. 

 
Yes. Putting an enclosure under tension, like a brace in a speaker cabinet, actually raises the fundamental frequency, but the important thing is, it changes, so if you hear a change, it might just be an enclosure problem, and you know what to do. My money is on something other than enclosure problems, but keep listening and let us know what this turns out to be. I've heard beautiful harmonies on headphones only to discover that half the sound was coming from someone playing the TV real loud. You could have very large moles in your yard. So pop off the headphones when you hear this rumble to make sure it's not ambient.

 

[nick n]

Instead of dealing with those Hackamichi's and the rumble (and I forget to eat when I get in the ZONE), I just redid the Alder Woodies, pulled out all the dense felt circles and the stale air inside, and only put cotton in there I had cut off of a long strip of cotton ball stuff, completely filling the space with that alone. That felt was too dense and seemed to act as a mild reflector,( -- -- --- ---- ------>
Yep that's it. Sans felt. Sans anything but cotton. Sim.ple.
And bingo.
 Serious night and day difference from before in the bass dept.The deep stuff is there punching my eardrums. Bass ports seem to work too, but I don't want to keep making em larger 3/32 is good for now given the size of the insides. Tempted to open up the Hackamichi yet again and simplify, but it's a different beast altogether and excels in soundstage. The angled driver thing. May have to if that above vibe thing keeps up.
I'll test those others later. This is too darned good right now.
Testing the tests to prepare for the test off which to base the next test.
 
Holy crud. I pulled the dense felt out of the Hacks and replaced it with cotton. left the interior covered with the self adhesive thicker stuff due to it's larger space inside the cups.
Nuts.
just like the Woodies but slightly better somehow.
 Wonder if the issue went away.
 
On a side note I really would like to extend my thanks to everyone that has contributed to this thread.
 

 

[Armaegis]

Quote:

Yes. Putting an enclosure under tension, like a brace in a speaker cabinet, actually raises the fundamental frequency, but the important thing is, it changes, so if you hear a change, it might just be an enclosure problem, and you know what to do.

 
Ah nuts, I said it went down didn't I? More mass should lower it, tension should raise it.

 

[wualta]

Aaah, don't worry about it. Like I said, in this case the important thing to notice was simple change. But then, turns out he's got cotton balls, a disease the March of Dimes is still trying to conquer, and they made his rumblies all go away.
 
I would imagine they'd have to be stuffed in there mighty tightly to get appreciable absorption. Now, are these the polyester floofy-poofy cotton balls, or real cotton balls?
 
I too would like to take this opportunity to thank everyone who made this thread (and by extension this forum) possible. The object certainly wasn't to make it go for 7 years, but we may get there regardless.

 

[nick n]

oh no good sir these are very sanitary cotton balls, real ones that were slightly elongated for some reason, they weren't in the typical shape.It was a long tubular piece ( seriously )
Jeeze I hope this is read in context.

March of Dimes hahahah haven't heard that for years!
Surprisingly they weren't packed in there super tight it could be that plus the initial insides were adequate to begin with.  Holy this is getting wierd the wording, but it's in all seriousness.
Holding them beside each other to compare the feel is totally different and not as great ( the polyfill is lame )

It's the fine textured cotton not coarse at all. like the medical stuff that comes in pill/vitamin bottles, you know the bottles that are huge then full of %90 cotton with the vitamins at the bottom of the bottle.
 
Time for more tests.

 

[symphonic]

Do you think that the T50RP drivers could be used as actively crossed (using a PC) tweeters when not being used as headphones? This would be in a near field setup using VST host to do the crossover. The concept would be to be to remove the headphones from a 2-way system when in use, and replace them otherwise. My headphone baffles are already designed to be easily oriented/removed.
 
If SFI tweeters work for headphone drivers, the idea should work in reverse right?
 
It would be funny to be able to pick up the tweeters from your stereo and take them with you.

 

[wualta]

I think it would work. They'll take, what, 3W full range, so they should take ten times that if they're band-limited. Cross 'em over high enough so they don't melt (say, 3k) and it should work. Were you wanting dipoles?