@teajay , that’s a very interesting configuration Role Audio is using in the Starship model. Thank you for bringing it up and for your excellent review.
That four-woofer, tweeter-in-the-middle cluster is something I haven’t seen before in high-end audio. The format is common in the bass cab world, but with much bigger drivers, and of course the goal posts are in a very different place from where they are in home audio. My instinct is that this configuration would be much easier to get wrong than to get right, but that the wide bandwidth of modern drivers makes it feasible.
Role is using a first order crossover, which implies that the drivers have exceptional bandwidths. Now one of the characteristics of any odd-order crossover (which obviously includes first order) is a tilting of the axis along which the drivers’ outputs sum in-phase. Then there is also a null in another direction, where the drivers’ outputs sum out-of-phase (cancel). Typically these two directions are in the vertical plane, one above and one below the central axis. The symmetrical cluster smooths this out, and if the tradeoffs are juggled right (which presumably in this case they are) the whole really is greater than the sum of the parts, as the summation lobes can fill in what would otherwise be a discontinuity in the off-axis response in the crossover region.
Of course I don’t KNOW that’s what the designer did, but judging by your description of Muddy Waters’ voice, based on your memory of hearing him live, I suspect Erol Rickets is getting the off-axis response right, which is much harder to do than getting only the on-axis response right. I tip my virtual hat to Role Audio and Erol Rickets.
You commented on the bass performance, and I’m sure the transmission line loading plays a role, but also the Starship has FOUR motors active in the bass region. My experience in the bass cab world indicates that sheer horsepower (combined motor strength) correlates well with bass "slam", and the midwoofers in the Starship have the most powerful motors I have ever seen in such a small woofer whose other parameters are good for making bass. The motor is more like what you might see on a good 6" or 7" woofer. I don’t recognize the tweeter but presumably it is likewise exceptional in its own right - this sort of design is very demanding of the drivers, and may well not have been practical just a few years ago.
I usually don’t get excited about cones-n-domes-in-a-box, but I think this one looks like something special.
Again, thanks for bringing it up! Not that I’m "in the market", but now I’d REALLY like to hear the Role Audio Starship.
Duke
