Both have pros and cons. For daily use, I prefer copper. One factor is weight, aluminum coil keeps the moving assembly lighter. Although copper has higher conductivity so it will handle more......wait, hey I remember this topic a few months back Mike from Shocker was talking about which is better, let me find it......................
...Aluminum vs Copper windings...
Yes, copper is a better conductor than aluminum...so lets just get that out in the open right here right now! Copper will absolutely handle more power than aluminum, the reason you smell the aluminum more is that with the same power applied the aluminum will actually get hotter which is a bad thing...however, when you come to the realization that you can get the same end result with less power from the aluminum, you simply adjust the power ratings accordingly and for daily driving the problem is solved!
Now, with that being said, if you look at the mass index of copper vs aluminum, you will see that an equal winding width and impedance of aluminum albeit a larger guage of wire still weighs less than the copper counterpart! This is not something that just pertains to car audio guys, do some research...It is a very simple concept, the equal winding and impedance aluminum coil simply weighs less and thus is more efficient...no secret voodoo going on here!
Now, titanium vs aluminum...that is an interesting topic as well! Yes, per thickness titanium is stronger than aluminum and thus "should" be a better former material! However, it has been my experiance that if the titanium was actually thinner than the aluminum that although it had more "strength" it was also more prone to breakage and there are also more issues with glue adhering to the titanium...further, back when I tried to work with titanium a few years ago you couldn't get the bottom of the titanium to roll like you can aluminum...the titanium was cracking and splitting when rolled at the bottom! Perhaps someone has solved this issue and found a bonding agent that holds better now, I have no clue!
oh, not having the bottom of the former rolled over the windings = very bad things in the spl world, so to me that was a big deal! As for the adhering agents...I was unable to find any glues that adhered well to nomex, craft paper or cloth that would stick well to the titanium...the problems that I had was litterally the reinforcement would litterally slide off of the titanium in high power applications...again, maybe someone has found a fix for this in the past couple of years, I don't know!
As for moving mass and spl I'll just say, "to each his own!"
you are the man zac.that dude mike from shocker don't live to far from me in ohio,a few of my friends have his subs.i was wondering about the coils cause i was looking at the hdc3's and aluminum coils made the sub like 100 bucks more each