Designing Own Speaker Elements

[Ultima Thule]

Hi,

I have wondering about making own speaker elements for a long time, and I make my first post inte the subject here to hear with you and try to collect data and other relevant information how and what to know about.

I think we can be quite freeminded in this thread and try to come and list some important things to know, and were to get the material.

I wonder especially are there anywhere somwhere to buy parts that can be used for making own speakaer element.
Parts like basket, cones, spider, voice coil (coiled and uncoiled) etc.

What kind of materials should be udes like
- conematerial
- magnet types
- pole parts and what kind of metall
etc.

On the theory part I would like to collect from a pragmatical point of view information in this thread things like what is "good" and "bad" practise, but also pure teoretical information like hos to calculate the magnetical field when designing the pole parts and using of a specified magnet.

SW for diffrent tasks that could be good to use when trying to develope own speaker elements, the SW may not necessary be done for speaker development but could give some aid.

Well, and all sorts of comments in general are wellcome, all accept "negative" support from those who don't think it's possible!

BTW, have anybody made their own speaker elements?

Cheers Michael

[GordonW]

Well, anyone who can recone speakers, has the potential to "make" their own speaker... to an extent. You're still limited to existing available magnet/basket assemblies, but pretty much, everything else is changable.

I've done some very basic mods, like mix-and-matching voice coils and cones... and it's interesting to see some of the UNINTENDED effects. Geometry can be a real bear, when you start mounting voice coils to cones to surrounds to baskets. But, if you're ever going to learn HOW this stuff works, this is part of that learning process, IME...

Regards,
Gordon.

[wimms]

For inspiration, check this: http://home5.inet.tele.dk/f-hammer/index.htm

SW, eg. FEMM http://mgc314.home.comcast.net/femmexample.htm

Magnets, Field-coil, Neodymium, Alnico.

[hunter audio]

hi

well heres a start :-

driver type :- Low frequency

cone type :- Re-inforced - Kevlar or Fibre glass / for tonal quality / composite fiber filling - with a heavy pulp beating and mixing process- - non press with non - hygroscopic pulp binders cone

surround - upon escursion limits - natural rubber - moulded - or foam - if intended for pro audio fabric surrounds - m roll or progressive m , or accordian or asymetrical

Spider :- large with deep corrugations - normal or progressive
( depending on limits ) , flexibility - medium , better if silcone doped - (helps cooling)

magnets :- wet pressed y 35 or above - for a linear (linear difficult to achive though) then good BH curve

Pole material :- low carbon cast steel - or forged from 1008 billets - then either the top layer machined off (peeled) or hydrogen annealed

Pole design - Field symmetry and vc inductance stabilisation - cooling design

Basket - pressure cast aluminum - moulded to your design / size of cone - surround clamping diameter etc.

voice coil - Hight temp Al / Cu Flat Wire - Spiral Edge Wound on Glass former (with high temp adhesives) - then slit - backed - ofc welded leads - solder tinned

Lead wire - paraffin doped high quality

Gold terminals

Rubitek Gaskets

High Quality High Temperature Adhesives -

Then a good test setup to evaluate the first prototype - measure vc temp - and power test - check distortions and evaluate to minimise or best eliminate all problems

Suranjan Das Gupta

Transducer Design Engineer

[1967cutlass]

it isn't worth doing, bottom line.

[Mr Evil]

Originally posted by 1967cutlass
it isn't worth doing, bottom line.

Most DIY isn't 'worth doing', but that's hardly the point.

[1967cutlass]

Originally posted by Mr Evil

Most DIY isn't 'worth doing', but that's hardly the point.

i disagree. you can make better loudspeakers for the $ than buying them. with making your own drivers thats nowhere near the case.

[Mr Evil]

Originally posted by 1967cutlass
i disagree. you can make better loudspeakers for the $ than buying them. with making your own drivers thats nowhere near the case.

I disagree with that. Sure it's possible to make very fine DIY speakers, but for most people there is a limit because of the money needed for test equipment to squeeze that last bit of performance out. For instance an anechoic chamber is beyond the reach of most DIYers, but for commercial products the cost can be spread out. There are cases where it may be worth it monetarily, but that is not the only, or even most important reason for DIY.

[capslock]

Cone and surround have usually been optimized in commercial drivers, especially from the traditional European manufacturers (d-s-t, Seas, Audax,). There is little that can be gained from building something from scratch, with the exception maybe of a multilayered, sandwich carbon fibre cone, which may be just too expensive to manufacture for these makers. But still, expect to go through many iterations before it works well.

It might also be worthwile to optimize cones, i.e. cut edges off similar to what Vifa does, or put local edge reinforcement on the Seas alu cones.


The big field for improvement is motor design. Most motor designs on the market today were made before full FEM analysis was widely used. Even the Seas Excel motors leave the gap unshielded, and careful optimization may lower their distortion even more.

There are a couple of nice motor designs out there (Usher, Dayton RS, Adire), but all of these, IMHO, could do with optimization of their cones and surround (Dan will disagree with me there...).


Greetings,

Eric

[hunter audio]

hi

I am into pro - audio , hats off to the following including their application , usage - over all design to their selection of cone material for the type of driver

in the order i have been impressed by

1) Meyer sound 2) Peavey 3) JBL 4) RCF & EV

Suranjan