As always, I’m honored to see this much speculation about our products. I’m happy that we can spark some interest in such an extremely crowded market! So let me try to clear up a few things here.
Firstly, the idea that this is a speaker we earn more money on is not true. We have had to cut into our margins to offer it at this price point compared to the Mk2. The Satori 7.5" woofer is multiple times more expensive than the SB17NRX2 we used in the Mk2. The tweeter in the Mk2 was a custom version of the SB19ST, and the new tweeter here is also a completely custom design made by SB for us. It’s around three times the cost of the old tweeter. While it does use the same dome as the 26ADC, it is otherwise a completely different design, featuring what the engineers at SB (who are located just 35 km from us, so we work very closely with them) call a “Matrix Neo motor structure.” It’s a really nice-sounding tweeter, with breakups around 25,000 Hz.
Now, I know this might not be the place to get into the objective vs. subjective discussion, but despite not measuring as well as the older, cheaper tweeter, it does sound significantly better ;-) The treble performance of the S400 has always been what most people gave negative feedback on, despite that being arguably the strongest objective aspect of the S400.
So just to clarify: the cost of building the Mk3 is significantly higher than the Mk2 because of this, and it’s not like parts have become cheaper since 2021, quite the opposite, sadly.
We had to find some savings in order to keep the price as close as possible to the Mk2, and moving from passive radiators to bass reflex is one place where we could save money. However, passive radiators were not really needed here, due to the larger cabinet, as we aimed for the same low-end extension as the Mk2, just with much more authority and headroom thanks to the new woofer. It’s quite crazy how much larger the Mk3 sounds in direct comparison, and how much louder and dynamically capable it plays.
With these new, better drivers, we were able to take advantage of a simpler crossover using a 1st-order design. After the extremely long development of the E50, this has become something we really love the sound of. It does hurt vertical measurements for sure, and it wouldn’t be a speaker I would recommend for nearfield listening. At 2 meters and beyond, however, we do not notice any shift in tonality when moving around, standing, or sitting it remains well-behaved still.
The crossover is also an area where we save some money due to its simplicity compared to the Mk2. That said, we are still nowhere near the budget-quality component choices of many competitors in this price range. We’re using Jantzen Cross Caps, SuperRes resistors (ceramic for notch filters), as well as even thicker air-core coils (1.6 mm) compared to the Mk2 (1.4 mm). No iron-core coils here.
In terms of sound, the tonal balance is very close to the S400 Mk2, so customers who like that sound should feel right at home, but they should also notice significant improvements across the board (bass, midrange, and treble), as well as the obvious increase in headroom.
It’s true that we are slowly moving in a different direction with our passive speakers, where measurements are not the sole factor dictating how a speaker is tuned. Of course, we still rely on measurements, it’s not like we are working blind, but we are making deliberate choices to achieve what we believe is better sound, even if that goes against theoretical standards. The E50 was a project where we had prototypes that measured much better than the final version, and we’ve documented this thoroughly on the product page for those interested in the development process and design decisions.
The S400 Mk3 still measures very respectably. It could have looked better with higher-order filters, of course, and with this tweeter, we could also have pushed the crossover point lower than in the Mk2 to further improve vertical performance. But who knows, if ASR users push us hard enough, we might do a batch fully optimized for objective performance ;D
We are not fully finished with measurements yet, but of course we will have them on the site once ready. For now, here is a draft of the prototype CEA plot from the NFS. We’ve made some small crossover adjustments since then. This measurement extends to 40,000 Hz on the Mk3 (not the Mk2), so you can clearly see the tweeter breakup as well.
I have attached both the S400 Mk2 and the S400 Mk3 CEA for comparison. Keep in mind that they tend to come out cleaner in Erin’s reviews (you can compare his Mk2 data to ours), so when he tests the Mk3, it will likely look a bit cleaner than what you see here. We do plan for Erin to be one of the first to receive it, if he has the time.
But we have done so many drafts of floorstanders that have never seen the light of day, so no promise yet 
