Another mamoth thread, with some very interesting ideas (that sadly never got off the ground) is the DIY Parthenon thread: http://www.diyaudio.com/forums/showthread.php?s=&threadid=25376&highlight=
Depending on what output you're looking for, it's generally better to consider all the different sections together from the beginning
Don't be put off though, seeing threads like this make me wanna start this all up again...
Depending on what output you're looking for, it's generally better to consider all the different sections together from the beginning
Don't be put off though, seeing threads like this make me wanna start this all up again...
I have read every word in the 28 page Parthenon thread. Too bad no one every got around to finishing one. I also would like it to be high excursion; don't need 8-9" though
I also have FEMM but haven't done much with it. I opened it a few times and was lost. I am going to have to check examply problems or something.
For the motor I was thinking I could use a bunch of my ceramic doughnuts stacked N to S together. I have some older ceramics that were used inside the voice coil and there was nothing on the outside. Is this design bad? They used to do it a lot but stopped and started surrounding the VC with the magnets and just having the metal pole piece.
I also have FEMM but haven't done much with it. I opened it a few times and was lost. I am going to have to check examply problems or something.
For the motor I was thinking I could use a bunch of my ceramic doughnuts stacked N to S together. I have some older ceramics that were used inside the voice coil and there was nothing on the outside. Is this design bad? They used to do it a lot but stopped and started surrounding the VC with the magnets and just having the metal pole piece.
Aluminium former will form a shorted link as someone already pointed out. Cutting a slot will again spoil the stiffness. I think professional outfits use a special tool that forms a temporary bobin for winding the coil and the tool retracted and withdrawn after the glue has set. Here in India teflon is available in industrial materials shops.
For high excursion the factors to concentrate on:
(a)The surround and spider should allow the movement: large diameter spider may be required. I have also seen raised spiders in some drivers.
(b)For linearity at high displacement, the length of the coil should be sufficient, so that a part of the coil is inside the magfield at extreme positions.
The idea of magnet inside the voice coil sounds interesting. But remember that the field strength depends on volume of the magnet material. For a given material (ceramic in your case), bigger the magnet, stronger the field.
As for assembly-sequence, I have seen one manufacturer magnetise the magnet after the whole assembly is done. I think it may be difficult to keep the pole pieces in alignment with a strong magnetic field, during the glueing process.
A thought on magnets: have you ever taken an old computer hard-drive apart? They have extremely strong, tiny magnets. I wonder if they can be used in a speaker, because the read/write head in a hard-drive is driven by the voice coil principle.
For high excursion the factors to concentrate on:
(a)The surround and spider should allow the movement: large diameter spider may be required. I have also seen raised spiders in some drivers.
(b)For linearity at high displacement, the length of the coil should be sufficient, so that a part of the coil is inside the magfield at extreme positions.
The idea of magnet inside the voice coil sounds interesting. But remember that the field strength depends on volume of the magnet material. For a given material (ceramic in your case), bigger the magnet, stronger the field.
As for assembly-sequence, I have seen one manufacturer magnetise the magnet after the whole assembly is done. I think it may be difficult to keep the pole pieces in alignment with a strong magnetic field, during the glueing process.
A thought on magnets: have you ever taken an old computer hard-drive apart? They have extremely strong, tiny magnets. I wonder if they can be used in a speaker, because the read/write head in a hard-drive is driven by the voice coil principle.
I can get 14GA galvanized sheet metal from work for free, will that be ok for the basket and to transfer flux? I don't want to spend hardly any money because I don't have it right now. I will try an example coil using a beer can aluminum former and Minwax polyurethane to coat the coil. I don't even have enough money to get kapton tape so is there any common household item that will work to go over the former? Single layer of electrical tape?
Silver winding
A friend gave me some pure (99.99) silver wire from some speaker interconnects he had made. With the scrap silver I made a pair for myself and really noticed an improvement in clarity of my audio. Long story short I got to thinking, how could a system wide rewire of silver benefit audio quality?
I have an old pair of Pioneer Dss-9's that I thought would make good candidates for the conversion because the woofers need reconing (have new cones).
If I go to the trouble of rewiring and reconing the speakers, I might as well continue the silver replacement all the way into the speaker itself (IE: voice coil, tinsel wire leads)
I already know I crazy my question is am I insane?
Are there benefits to be had in winding a silver voice coil?
A friend gave me some pure (99.99) silver wire from some speaker interconnects he had made. With the scrap silver I made a pair for myself and really noticed an improvement in clarity of my audio. Long story short I got to thinking, how could a system wide rewire of silver benefit audio quality?
I have an old pair of Pioneer Dss-9's that I thought would make good candidates for the conversion because the woofers need reconing (have new cones).
If I go to the trouble of rewiring and reconing the speakers, I might as well continue the silver replacement all the way into the speaker itself (IE: voice coil, tinsel wire leads)
I already know I crazy my question is am I insane?
Are there benefits to be had in winding a silver voice coil?
You might find the following interesting:-
Low TCR wire in high power audio coils
us5664023
Publication date: 1997-09-02
Inventor: BUTTON DOUGLAS J (US)
Applicant: JBL INC (US)
For electric coil windings, particularly in moving coils such as the voice coil of a heavy duty bass loudspeaker or other electro-acoustic transducer, the present invention has found metallic materials, as alternatives to copper or aluminum in the voice coil wire, that can provide increased available maximum SPL (sound pressure level) exceeding an empirical limit, just under 120 dB/1 m, that has been found to apply to various loudspeakers of known art regardless of efficiency and structural differences. Through study of known art regarding this limitation and theoretical analysis of the factors in voice coil structure and design that limit the maximum attainable SPL, a novel basis for selecting voice coil wire material has been developed. By selecting wire material for low TCR (temperature coefficient of resistance) along with suitable resistivity and density, rather than for low resistivity alone which has conventionally dictated copper or aluminum, the present invention has led to the identification of new wire materials that can increase the available SPL. Such materials include alloys of aluminum containing between two and five component basic metals selected from the following group: magnesium, silicon, manganese, zinc and copper. The alloy Al Mg(3.5%) in extruded form yields maximum SPL 1.5 dB above that of pure aluminum and 3.32 dB above that of pure copper.
Regards
James
V to the [MF] C, homeboy
2 Q’s
1) Does the former have an effect on the voice coil, for instance does an aluminum former behave differently then a plastic, copper, etc...? My intuition tells me that from an electromagnetic standpoint there must be differences, but are any of these audible?
2) Does anyone know a good software program that would aid in the design process?
I am going to wind my own VC’s for a recone job and I am currently planning or using silver(winding) and aluminum(former) or visa versa(open to suggestions). The former will be insulated with Kapton tape. I am interested in finding out if and how changes in the materials of the VC will effect its performance.
2 Q’s
1) Does the former have an effect on the voice coil, for instance does an aluminum former behave differently then a plastic, copper, etc...? My intuition tells me that from an electromagnetic standpoint there must be differences, but are any of these audible?
2) Does anyone know a good software program that would aid in the design process?
I am going to wind my own VC’s for a recone job and I am currently planning or using silver(winding) and aluminum(former) or visa versa(open to suggestions). The former will be insulated with Kapton tape. I am interested in finding out if and how changes in the materials of the VC will effect its performance.
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