Al vs Cu

[Alex Lancaster]

Hi:

Have You noticed that almost all of JBL´s current Pro components use Aluminum for the voice coil?

I can´t see the reason, copper is more conductive per area, expands less, and has a slightly better coefficient of resistance/temp; It can´t be weight or cost, for what they charge, they could be using silver (Ag), which is even better.

Am I missing something?

Alex.

[Robh3606]

My quess would be moving mass and inductance both of which is lower with aluminum. Better high frequency extension. Any other ideas??

Rob:)

[John Y.]

Rob,

I can see your reasoning with regard to drivers designed to extend the HF, but for LF, I would think that copper would be better, since we usually try to add mass (mass rings, etc.). JBL used to put copper on their LF units, but now seem to use aluminum. I wonder why?

John Y.

[JBLnsince1959]

I've been wondering about that myself. Can anyone enlighten us about this?

rick

[Roddyama]

My bet would be costs.

[JackyTran]

Hello,
I don't think they save much cost between Al and Cu- may be technical issue.
And I wonder why the wires inside my 4315 is so small? So are other JBL monitors? Anyone of you have tried to replace the wires by better Cu/or Silver ones?

[Alex Lancaster]

The cost of silver for a 2242, the largest, I think, would be maybe $20, about 5% of dealer cost, not significant, considering the lower resistance and power compression which seems to worry JBL so much, so the cost diff. of Cu and Al do not matter, there must be something else.

I also noticed the thin wiring inside, if You just think of Ohm´s law, thicker wires would not make a real diff., the woofer is more than 4 ohms DC, for these short wires 0.1 ohm less is nothing, however there are the transient, capacitance and reactance issues, so if You can, change the wiring IMHO.

Alex.

[Hofmannhp]

Hi Folks,

sorry wrong thread........please look for the new thread to this point.

HP

[Roland]

Planned obsolecense?? Aluminum will rust/wear out earlier. No advantage to use Al in LF drivers that I am aware of??. Minimal Al advantage in MR via lighter VC and better transient response..

[subwoof]

With Al you can add mass. With Cu you have to live with it. If you want efficiency you need light weight. The ONLY place where Cu coils are an advantage is in VLF foam surround cones that needed even *more* mass.

And these are useless in the pro SR market that make up the bulk of the JBL component sales.

I would also speculate that the Al is *not* pure but an alloy that is much more resistant to fatigue. And that the formulation is closely held..:)

Ever try to bend a stop sign? that's Al but stiff as hell due to alloys...

Make one out of Cu and it would bend and deform with the first wind.

Make it out of Ag and it would turn black and fail early. You cannot prevent O2 from reacting with it eventually.

sub