@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.
Thanks for the kind words regarding my review. Yes, you should hear this speaker. This speaker is extremely musical and offers wonderful performance with a very interesting innovative design approach.
By the way, I have received numerous Emails regarding how to hear this speaker. Well, if you live in the Chicago land area, my review pair are still in my system, just give me a call to setup a possible time. Masks are required! You could also contact Mike Kay (Audio Archon) who is a NSMT/Role dealer to discuss other possibilities to hear this model.
You bring up a problem about first order crossovers that is technical enough but one that any speaker designer worth their salt should be able to solve with the array of currently available computer based measurement systems (I use MLSSA, LMS, and CLIO) by running simulations.
With regard to the driver configuration of the Starship SE, it is not inspired by “the four-woofer, tweeter-in-the-middle cluster from the bass cab world.” The bass cab world is not a part of my orbit. Instead the Starship SE design is a result of step by step research and development that dates back to the 1990s.
The provenance of the Starship SE has its origin in the NSM Audio Model 5 that was reviewed by Soundstage back in 1999 That review can be found here. Note the drivers used in the Model 5 and their configuration. Having successfully used a SEAS concentric driver in my NSM Audio 20M also reviewed by Soundstage here, I consulted with the SEAS engineers at CES in the 1990s as to whether or not they had a free standing version to the tweeter used in the concentric driver that would allow me to simulate the close coupling of woofer and tweeter approximating the relationship in the coax. They suggested the tweeter used in the Starship series which I imported directly from SEAS because it was not available in the US. Subsequently it was distributed by Madisound.
The first speaker designed in the Role Audio Starship Series—a modular line of speakers-- was the Kayak, which was based on the Model 5 and had the same driver configuration. The Windjammer is the transmission line version of the Kayak. Note something very important: I am using drivers that work well in both acoustic suspension and in my transmission line designs. Next came the Discovery. The Enterprise is the transmission line version of the Discovery. To develop the Enterprise I had to solve the technical issues involved in mating two transmission lines – a configuration I had not seen before or since. So the Enterprise is essentially two Windjammers in one cabinet. Later on came the challenge of designing a speaker with twice the power of the Enterprise – the Starship SE. The first speaker with four transmission lines, to my knowledge. If you draw a vertical line down the center of the Starship SE you can see that it is essentially two Enterprises or four Windjammers. The Starship SE tweeter is different to accommodate the increased sensitivity of the Starship driver configuration. Note in the Starship SE the drivers are spaced even closer together than in the Enterprise. The pedigree of the Starship SE is well established in the series of reviews of the Kayak, Discovery, Windjammer, and Enterprise.
Now onto a different issue. No! I am not using mid-woofers in the Starship that have “the most powerful motors” you “have ever seen in such a small woofer whose other parameters are good for making bass.” Quite the opposite. What I am using is a different transmission line technology. The motor of the woofer is not “more like what you might see on a good 6" or 7" woofer.” And the design is absolutely not “very demanding of the drivers.” Quite the contrary, compared to ported or acoustic suspension designs at a similar SPL these woofers are hardly moving. Reduced cone motion and reduced distortion at similar SPL is one of the hallmarks of transmission line designs.
I think this misunderstanding of my designs is what led to your earlier comments about the NSMT Chorus and your disbelief that the “Chorus has a sensitivity of 96 dB, bass extension to 35 Hz, and an internal volume of about 1/2 cubic feet.” That level of performance inheres from the short transmission line technology and TL-ABC port tuning that I have developed.
There are several reviews of Role Audio speakers with even smaller internal volume: the Sampan FTL (.12 cubic feet), Sampan (.13 cubic feet), and the Windjammer (.36 cubic feet) that have 35 Hz to 20 kHz frequency response. A Google search of the smallest speaker, the Sampan FTL which weighs 4.5 pounds and is 8 X 4 X 9.5 inches, will show an image of a composite MLSSA measurement of the TL-ABC version that is +/- 3.5 dBs from 35 to 20kHz. Hard to believe but true. The Sampan FTL was first shown at AudioKarma Fest ‘07 and there are comments online about its performance from that showing.
The imaging, soundstaging, and bass performance of the Starship SE should not be surprising to anyone who owns or has read the reviews of the Windjammer and Enterprise, considering the Starship is essentially four pairs of Windjammers or alternatively two pairs of Enterprises.
the Sampan FTL which weighs 4.5 pounds and is 8 X 4 X 9.5 inches, will show an image of a composite MLSSA measurement of the TL-ABC version that is +/- 3.5 dBs from 35 to 20kHzThe devialet phantom speakers are small enough to be held in your hand yet they can do 20hz bass. So obviously these sampan speakers are not very good considering what the phantoms can do.
Yes Duke, very intriguing design. Getting a transmission line right is not easy at all. Usually it becomes trial and error. The math only gets you near the ball park. The other problem as you mentioned is the bandwidth problem. With a 6 dB/oct crossover you would have to keep the crossover high to prevent overloading the tweeter. So either you are limiting the headroom of the speaker or you are asking the woofers to run higher then perhaps they should. If this is the case then a subwoofer system crossed on the higher side will help a lot. Otherwise, this speaker should image well and certainly has enough midrange power to go convincingly loud as long as the tweeter is kept out of the action. I'm surprised they did not use a 12 dB/oct crossover. Using an active digital crossover and biamping would be a natural for this design.
douglas_schroeder wrote: My reference level bass extension for a floor standing speaker is at 25Hz +/-3dB, or better.
I ask the same question about reference.
Right now, I am listening to a pair of Tyler Acoustics MM5X's built as a floor stander with 26 dbl in the bass from an 8 ohm, 88 sensitivity rating.
Good tonality, decay, dynamics, and they seem to disappear in my room with my setup (CJ preamp and CJ tube amp).
This is from a guy who also has a pair of Thiel CS 5's and used to own Maggie 3.6s.
And I do not mean to offend anybody and have not heard the Role Audio Starship SE. :)
The devialet phantom speakers are small enough to be held in your hand yet they can do 20hz bass. So obviously these sampan speakers are not very good considering what the phantoms can do.
Transmission lines are very impressive if we are talking cabinet volume to bass in a passive design.
If you want to go digital dsp active....holy crap, This new homepod mini will blow your mind for size to bass output.