George; a fellow club member dropped by a club where my band was playing. I was switching back and forth between two basses. At the break the club member remarked how very different the two basses sounded, to which I agreed.
The similarities: same rig, both were Alembic Series I basses, both had standard point bodies with Mahogany cores, both had Maple and Purpleheart necks. Both had TI Jazz Rounds, both sets of strings had high mileage.
The differences: one bass is a 34 scale, the other is 32. One set of TI's is 34 scale, the other is 32. One bass is tuned to E, the other is tuned to E flat. One bass has a Maple top and back, the other has what I think is Walnut.
It seems to me that the difference in top and back woods must be the main factor in the significant difference in these two basses. When I tune the second bass up to E and it doesn't change the tone all that much, no where near enough to account for the main difference. The Maple bass has a much more pronounced high end; much brighter. The Walnut(?) bass is darker with no where near the high end of the Maple.
I also have an all Maple Essence; Maple neck, Maple body, Maple top. Very bright and aggressive bass. I have a Spoiler with a Mahogany body and Koa top; no where near as bright, much darker. I have a six string Essence with Mahogany body and Walnut top; also no where near as bright as the Maple basses. (The fretless basses are of course fretless, which is a big difference in itself, so I won't mention them.)
My limited experience with Alembics suggest that there is indeed a significant difference in tone even when everything is the same except the top and back body woods. Now I may be wrong in my conclusions, I certainly don't have the experience of Mica and Val or some of the other club members like Rami or Steve. Mica and Val both have stated that having Coco Bolo tops and backs makes a significant difference in tone. My Maple Essence does not have a huge bottom end. If I could change the body from Maple to Mahogany, I'm sure it would change the tone immensely, adding more bottom and low-mid. If I could change the body of my Spoiler from Mahogany to Maple, I'm sure it would brighten that bass up.
Now admittedly I play with a lot of high end in my tone and I spend a lot of time high up on the neck; and perhaps a lot of high end accentuates the differences in tone that different woods contribute. Perhaps players that roll off the filter and have a tone more in the low-mid frequencies, perhaps the differences in wood are less apparent to them.
When I first joined this forum, and my Alembic experience was just one bass, it was stated here that the neck woods contribute the most to tone, then the body wood, then the top and back laminates. It was even stated that the contribution of the top and back laminates was small enough that the choice of those woods could be primarily made based on appearance. However, Mica's remarks at that time concerning Coco Bolo seemed to contradict the statements about top and back laminates. My own experience, limited as it is, seems to suggest that even the top and back laminates can contribute significantly to the overall tone. And of course much has been said in this forum about how Ebony neck laminates affect the fundamental; but I don't have a bass with Ebony neck lams, so I can't personally address that.