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Old 13th January 2013, 12:52 PM   #101
Zen Mod is offline Zen Mod  Serbia
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as I said - I dunno much about drivers construction
it just looks that your surround is thick , and I know that thick surrounds (compliance) are leading to slow driver

however , it's better that I'm in wrong , and that your surround is thin and soft
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Old 14th January 2013, 07:57 AM   #102
Hentai is offline Hentai  Romania
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Hi Frank,

thank you for update on depron. good to know.
The thing about surround is that while Cms doesn't have a contribution to high frequency response, Mms does. You have to take in account the fact that at least 1/3 of surround mass is added to Mms along with cone mass, voicecoil mass, glue mass and 1/3 of spider mass.
Also, you will need to experiment to see if it provide a proper cone termination and this is the hardest part because you need a good mechanical impedance matching. With a good match the effects of radial cone breakup modes should be minimized.

With my project i am sourcing aluminum for my frame, try a couple more voicecoils and making a setup for distortion measurements.
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Old 14th January 2013, 06:18 PM   #103
Frank40 is offline Frank40  Denmark
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[QUOTE=Hentai;3325040]Hi Frank,

thank you for update on depron. good to know.
The thing about surround is that while Cms doesn't have a contribution to high frequency response, Mms does. You have to take in account the fact that at least 1/3 of surround mass is added to Mms along with cone mass, voicecoil mass, glue mass and 1/3 of spider mass.

Thanks Hentai, I did not know that, it is always nice to learn new stuff. I have be looking all over the internet for a "How to make your own unit" but I don't think there is a lot of info on the topic.

Here is a thought... To eliminate traditions between the voice coil and membrane and from the membrane and the surroundings you could make a combined unit like show below. This way you can make the hole thing extreme light, I am guessing about 3-4 g without the copper. Also you don't need to glue the hole thing together with more or less know glue spec's.

I know you don't have a lot of Xmax but this is no problem for me, as they will be cut at around 80Hz. Please coment.
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Old 14th January 2013, 10:07 PM   #104
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[QUOTE=Frank40;3325749]
Quote:
Originally Posted by Hentai View Post
Hi Frank,

thank you for update on depron. good to know.
The thing about surround is that while Cms doesn't have a contribution to high frequency response, Mms does. You have to take in account the fact that at least 1/3 of surround mass is added to Mms along with cone mass, voicecoil mass, glue mass and 1/3 of spider mass.

Thanks Hentai, I did not know that, it is always nice to learn new stuff. I have be looking all over the internet for a "How to make your own unit" but I don't think there is a lot of info on the topic.

Here is a thought... To eliminate traditions between the voice coil and membrane and from the membrane and the surroundings you could make a combined unit like show below. This way you can make the hole thing extreme light, I am guessing about 3-4 g without the copper. Also you don't need to glue the hole thing together with more or less know glue spec's.

I know you don't have a lot of Xmax but this is no problem for me, as they will be cut at around 80Hz. Please coment.
Frank, how is that any different from what we see today?
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Old 14th January 2013, 10:35 PM   #105
Hentai is offline Hentai  Romania
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Well i think it is a great idea, making the former as an extension of the cone. I would assume it would be difficult as a DIY procedure tho?
For a home system, high efficiency full range, i dont think we need to worry about the former handling large temperatures. I just needs to be thin enough and ridig enough.
Great idea Frank, do you think it can be done in diy conditions?
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Old 14th January 2013, 11:06 PM   #106
Johno is offline Johno  Australia
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Agree, very neat and economical thinking.
Possible to vacuum form as well. However the vertical wall of the coil former would be very thin compared to the more horizontal parts and the sharp angles will cause high stress regions and therefore need to be much more rounded - all stuff that is fairly easily addressed when designing the pattern.
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Old 15th January 2013, 05:33 PM   #107
Frank40 is offline Frank40  Denmark
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454Casull,
I haven't seen any speaker build in this way, but if you have seen it please post a link. The moving parts, voice coil, membrane, surroundings and the spider are normally 4 separate parts that are glued together to form one unit.

Hentai and Johno,

Glad you liked to idea. I think it can be done by us DIY's but I wouldn’t use the vacuum forming technique....as Johno mentioned, the vertical walls will be to thin. The tricky part is to get the thing of the former. I would use glass or carbon fibre, at this point fibre glass sounds best but haven't tried carbon fibre yet. I don't know if you know this, but you can get epoxy glue for many purpose some can handle high temp. and you can get a variety of softer and harder types. You can also ad different additives to change it's properties.

I have used a lot of different types of epoxy over the years designing and building air planes, so this will be my first choice. Now I will get some material and tolls to make a former for this new one.

Take care.
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Old 15th January 2013, 08:31 PM   #108
Hentai is offline Hentai  Romania
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I was thinking about carbon fiber as well at Magura's suggestion but I'm still not ready to give up on paper. Paper to me always been the best sounding cone material. Keep us posted on how things develop at your end Frank.
Meanwhile aluminum rods for the frame have arrived. Time to put them in the machines.
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Old 15th January 2013, 09:47 PM   #109
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Quote:
Originally Posted by Frank40 View Post
454Casull,
I haven't seen any speaker build in this way, but if you have seen it please post a link. The moving parts, voice coil, membrane, surroundings and the spider are normally 4 separate parts that are glued together to form one unit.
I did not see that everything was of the same piece.

As long as all performance requirements are satisfied, it should work quite well. The surround needs to have a relatively low stiffness, with high self-centering and fatigue life, and customizable damping. The voice coil former needs to be round enough, strong enough, resistant to high temperatures, suitable for bonding to the coil.
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Old 17th January 2013, 06:27 PM   #110
Frank40 is offline Frank40  Denmark
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Hi to all

Here is another thought, see the picture below. I have replaced the centrer pole with a magnet, this should work like stacking magnets and increase the flux and help to saturate the iron . Please comment.
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