Summer Project - Replication of MBL loudspeaker 101mkII

[Rullknufs]

I will follow this project with enthusiasm. I've heard the MBL 101 Extreme in Stockholm and it sure was a good experience

[bear]

Looks to be a straight forward magnetic circuit with a standard voice coil - looks very overhung - on the end of the "melon" petals... the VC pumps up and down and the petals move in and out in response...

otoh the VC may be pushed into the gap when the unit is assembled... gotta look closely at the pix, I haven't yet.

If you look at the Walsh (Ohm F) driver, it is really quite similar except the "cone" on the MBL is different...

The MBL is frightfully low in sensitivity, so be sure to max your magnetics and get the gap right...

I'd be concerned about the VC moving linearly in the gap, having seen how they assemble it. Very surprising to me that they seem to attach the "petals" to the VC former after the petals are connected to the opposite side. I would have expected to do it in the reverse fashion...

Also I am surprised at the damping material on the reverse side of the bass petals, and the fill inside the midrange...

seems to me that forming the petals accurately is going to be a bit of a difficult thing to do, and essential to the operation of the driver as well...

where did you find the pix of the manufacturing process?

Guess MBL is daring anyone to try it themselves!!

Please do post your progress, successful or not!!

_-_-bear

[Magnasanti]

Originally Posted by bear

Looks to be a straight forward magnetic circuit with a standard voice coil - looks very overhung - on the end of the "melon" petals... the VC pumps up and down and the petals move in and out in response...

otoh the VC may be pushed into the gap when the unit is assembled... gotta look closely at the pix, I haven't yet.

If you look at the Walsh (Ohm F) driver, it is really quite similar except the "cone" on the MBL is different...

The MBL is frightfully low in sensitivity, so be sure to max your magnetics and get the gap right...

I'd be concerned about the VC moving linearly in the gap, having seen how they assemble it. Very surprising to me that they seem to attach the "petals" to the VC former after the petals are connected to the opposite side. I would have expected to do it in the reverse fashion...

Also I am surprised at the damping material on the reverse side of the bass petals, and the fill inside the midrange...

seems to me that forming the petals accurately is going to be a bit of a difficult thing to do, and essential to the operation of the driver as well...

where did you find the pix of the manufacturing process?

Guess MBL is daring anyone to try it themselves!!

Please do post your progress, successful or not!!

_-_-bear

The pictures of the manufacturing process were found after days searching on the web finding literally all i could.. I will surely be posting progress updates but before that i am still learning about FEMM and magnetic circuit design. Also Mbl states that the other end opposing the V-C is attached to a thrust bearing what exactly would this add?

[bear]

On the bass "melon"? A thrust bearing??
Perhaps a mistranslation from the German?

I would think that over there is more or less a hinge, so that the bending motion is not impeded by stiffness. So, the hinge would need to have stiffness in the vertical direction (the way that the VC is pushing - that vector) but be able to bend outward to permit free flexing of the petals... or not. Pure conjecture.

It might be marketing hype too... the connection to the VC would likely be the *same* as the connection on the top.

educated guesses... or uneducated blabbering... either way about the same value?

_-_-bear

[VALEMAO]

Me too i'am tring to replicate it...after 3 years of R&D i realized mid and tweeter.
Quite sadisfay, but an updated version is ready to be realized ..
I am involved in woofer contsruction at the moment....
and i just wonder where did you read that the aluminum lamella are made of 2 pieces glued togheter?
Thikness?

[a.wayne]

Wow, difficult project , getting the mechanicals right will almost be as difficult as getting them to sound right , then of course the amplification necessary to power them to reasonable levels .. May I suggest laminated foil until you get the mechanicals right , before attempting carbon diaphragms..


MBL has been at this speaker for decades , the early ones where soft and delicate sounding ,

good luck !!!

[VALEMAO]

Originally Posted by bear

On the bass "melon"? A thrust bearing??
Perhaps a mistranslation from the German?

I would think that over there is more or less a hinge, so that the bending motion is not impeded by stiffness. So, the hinge would need to have stiffness in the vertical direction (the way that the VC is pushing - that vector) but be able to bend outward to permit free flexing of the petals... or not. Pure conjecture.

It might be marketing hype too... the connection to the VC would likely be the *same* as the connection on the top.

educated guesses... or uneducated blabbering... either way about the same value?

_-_-bear

Actually the gap where the lamellas are fixed has to be large enough to permit them to vibrate. The trick is to choose the correct glue. Mbl is supposed to use a silicone rubber glue. Furthermore, is very important that does exist an axial rigid connection to the thrust bearing, otherwise it works as a low pass filter.
I touched the lamellas wilhe the loudspeaker was sounding and it doesn't have a large excursion...as expeted.

[AVWERK]

That low sensitivity of these would improve if the motor was at the top pushing down rather than trying to pulse upward? Would it not?
I listened to these at our recent Newport highend show here in California and they are quite impressive.

Regards
David

[Remlab]

Magnasanti
Interesting photo of what looks like an MBL midbass prototype..
http://img.photobucket.com/albums/v5...r07/mbl063.jpg
By the way, could you please provide the link or links that the assembly photos came from? I tried to find them on my own, but had no success..
Seth

[Magnasanti]

Originally Posted by Remlab

Magnasanti
Interesting photo of what looks like an MBL midbass prototype..
http://img.photobucket.com/albums/v5...r07/mbl063.jpg
By the way, could you please provide the link or links that the assembly photos came from? I tried to find them on my own, but had no success..
Seth

LOTS of sites AND brochures as well from review sites they took along time to get. I could however point you in a general direction. Try searching for jurgen reis mbl (IMAGE), and a good one is mbl 101 PDF.Ill provide some links anyway it would be a pain in the **** to go find every pic again through the web so here are some links. https://www.google.com/search?q=mbl+...w=1280&bih=601