Driver Design

[DiscerningDave]

Hi All, this is my first post. I am attempting to design a speaker and I have some questions. I have searched the Internet and have not been able to find adequate answers.

The first question is in regards to the voice coil. In order for me to get a comparable Mms to stock speakers I need to use a thin wire (36 awg) to obtain a value of 6 ohms Re. This wire gauge is rated for only 0.21 amps, yet the stock speakers are rated at rms power values reflecting currents ten times this value. Am I correct in assuming that because a music signal is so dynamic one does not consider the rated rms current of the wire? If this is the case just how does one determine if the wire gauge is adequate for the application?

My second question is in regards to the suspension of the diaphragm assembly. Other than centring the voice coil in the gap, are the any intrinsic benefits to a spider? Are there alternatives to a spider?

Lastly, the only information I have found technical enough to design from are the two papers “Green Speaker Design” published by KLIPPEL GmbH. Are there any other good design guides out there?

Thanks

 

[woody]

Well here is one that doesn't use a spider. They bought the bankrupt Babb speaker company and I believe Babb used some sort of roller bearing. DC Gold Audio

 

[giralfino]

In order for me to get a comparable Mms to stock speakers I need to use a thin wire (36 awg) to obtain a value of 6 ohms Re. This wire gauge is rated for only 0.21 amps, yet the stock speakers are rated at rms power values reflecting currents ten times this value.

I think there is something wrong. It seems you are comparing a commercial driver with a x Mms and 6 Ohm Re, to a driver you are building, and the only way you can match the Mms is to use a 36 awg wire.
I once fixed a broken wire in a tweeter, and that wire is 3-4 times in diameter to the 36 awg wire you are thinking to use, so I would think that a 36 awg wire is simply unsuitable even for a tweeter. The fact that the reference driver is rated to a much higher value than 0.21A, is because it use a really thicker wire.
So in order to match the Mms you should change cone material or thickness or both.

Ralf

 

[wonderfulaudio]

Well here is one that doesn't use a spider. They bought the bankrupt Babb speaker company and I believe Babb used some sort of roller bearing. DC Gold Audio

Are there any links to a drawing or something?

 

[AllenB]

https://www.diyaudio.com/forums/mul...ld-coil-loudspeaker.html?highlight=field+coil

 

[Stal]

Mark Audio also do spider-less designs. The Alpair 7 MS and 11 MS (MS = mono suspension) and the Alpair 5.3.
Alpair | Markaudio

 

[markbakk]

Maybe it's time to recover some drivers from the scrapyard and do some destructive analysis... (been there done that).