AKG K240 Sextett--Grado'd AKG?

[Fitz]

Originally Posted by 003

Wait are you saying that in addition to baffle plate differences, there are also differences in the actual radiators?

Also were you able to test and see if the late baffle sounds the same as the mid baffle if you plug up the holes (maybe with electrical tape)?

EDIT:
Stupid me, the differences in the radiators are the fact that the early ones are orange.

During the close inspection of everything, it looks as though the diaphragm itself may actually be the same on the early version. The paper damping pad however is on the outside (back) of the plastic disc, rather than on the inside like the middle and late versions. Perhaps the different volume of air inside the radiators is what causes the difference in sound? The reason it looks so bright orange is because the orange plastic disc isn't covered on that side like the later versions. The diaphragm itself may be slightly orange, it's hard for me to tell for certain, but it has very little colour of its own.

I haven't tested whether plugging the holes makes the later style baffle sound like the middle one, but based on my current observations I have no reason to suspect that it wouldn't. Everything else appears functionally identical except for those four pinholes. My sextetts, like most, have the front grilles stuck fast, so they do not come off easily. Because of that, and now with these latest findings, I do not have any interest in going through the trouble to test sealing the pinholes. I'm going to operate under the assumption that sealing them will change the sound back to the middle style baffle plate, unless I hear otherwise.

[003]

The front grilles actually snap in and out. You can use one of those small flathead hobby screw drivers to pop it off. It will be easier if you pop it off by prying between the two little posts that snap in place as apposed to on top of them. You can tell where the posts are because on the grille there will be two spots where there are no holes, on either side of the driver. The posts are right under those two spots.

Anyway, using photoshop I have created pictures of the early, middle and late baffles based on what I have learned from you. Click them to supersize.

Early production (K240 Sextett EP, K240EP for short):


middle production (K240 Sextett MP, K240MP for short):


late production (K240 Sextett LP, K240LP for short):


EDIT:
Apparently some sextetts have the grille permanently glued in and you can not take it off without breaking it. If it won't come off with a bit of light to moderate (never enough to significantly bend it) prying, don't keep trying. You can still see the identifying features by shining a bright flashlight through the grille.

[Fitz]

Originally Posted by scompton

I can get the housing off of my sextets, but I don't know how to go past this without desoldering, which I don't want to do. With the housing off, I can see the back of the radiators. One has white radiators with an orange back, so it's type 2 or AB. The other has white radiators with grey backs. Without knowing how to take it apart, I don't know if the plate has pin holes. I assume they're not visible though the grill. It has decent bass but can get a little fatiguing.

One other difference that I noticed is that there is more behind the plate in the second one. The type 2 just has 1 ring of foam stuffed between the lid and the plate. The type 3 or 4 has the same ring of foam plus some other foam behind the radiators.

They all use one foam ring that is IIRC about 3/4" wide and 1/4" thick. There is no difference in the foam used between the versions. Rotten foam usually gets cut in half by the movement of the earcup, resulting in an inner and outer ring of foam, which by that point is usually crumbling and falling out of the earcup.

Originally Posted by NiceCans

there is a ring of "foam" behind the baffle plate around the circumference. It is not really foam but appears more like a very open firbe material like a course "Scotch-Brite" pad type of stuff. My assessment is that it is there for vibrational damping regarding the housing parts.

It's called reticulated foam; it is open celled foam that has undergone a special process to make it even more open. It makes the earcup movement stiffer so it doesn't just flop around.

Originally Posted by ericj

iirc it's main purpose is to dampen the motion of the pivot mechanism in the earcup, but it certainly has some acoustic effect as well.

Any acoustic effect it has is minimal, if there even is any, as I haven't been able to tell any difference with or without it.

[kg21]

I agree with the title atleast to some degree, the k240 sextetts sound imo is very direct/intimate, theres nothing in the way of the music and it doesn't color it much.

[Killercrush]

Wow, now those are some nice pics 003.

[Fitz]

Originally Posted by 003

The front grilles actually snap in and out. You can use one of those small flathead hobby screw drivers to pop it off. It will be easier if you pop it off by prying between the two little posts that snap in place as apposed to on top of them. You can tell where the posts are because on the grille there will be two spots where there are no holes, on either side of the driver. The posts are right under those two spots.

I know very well how they come apart, I have even taken the sextett apart once or twice before myself. As already stated, most of the grilles I've tried to take off my sextetts are stuck solidly (picture the entire grille bending significantly around where the post is, while the post doesn't budge), and the last time I tried to force one that was stuck, I ended up destroying one of the passive radiators. So forgive me if I'm not even going to attempt to see if the grilles on my late production sextett are stuck or not.

Your middle production photoshop is innacurate, also.

[003]

Oh, I didn't know some of them had stuck grilles, that sucks.

Whats wrong with the middle production photoshop? What do I need to do to make it more accurate?

[Fitz]

Every middle production version I've seen has a thin, light orange ring around the edge visible from the front. The white paper damping pad doesn't go to the very edge of the plastic disc, so some of the colour is still exposed through at the edge.

[003]

I'm on it.

EDIT:
Done. It's not very realistic but you get the idea.

[NoPants]

100$ shelled out to australia for a pair of these...I hope they're worth it haha

been looking to change it up with something of the close, intimate signature, but as far as a grado-ed sound I haven't really come back to it since the sr 80 and sr 125, both of which hurt to listen to, literally..