From my first encounter with Arendal’s speakers and subs, I have been greatly impressed by their performance and build quality. I was so delighted by the 1723 THX Monitors last year (
Arendal 1723 THX Monitor Review) that I had been eager to see what their other speakers were capable of. I opted to review the 1723 Tower S THX, the subject of this article, because I wanted to see what they could do as a tower speaker, but not merely as an extension of the 1723 THX Monitors which I already had experience with. The 1723 S THX series scales back the regular 1723 THX speakers for a smaller size and lighter weight but keeps the same basic design cues. In theory, this should give us a similar sound qualitatively at the cost of dynamic range versus the regular 1723 series. This is probably a worthwhile trade-off for most people since few users of the 1723 series are likely to take full advantage of their dynamic range. Outside of comparisons to Arendal’s other speaker lines, what does the 1723 Tower S THX deliver on its own? $3k is not an insignificant sum for most people, so what does Arendal deliver with this particular model? Does it keep the same value that Arendal has rapidly become known for? Read our in-depth review to find out...
READ: Arendal Sound 1723 S Tower THX Loudspeaker Review
I think there are some questionable design choices here. I can see you are worried about phasing.
I do have a correction to your report, or an addition if you like. The crossover to the upper woofers at 1.5KHz is fourth order low pass, but the high pass to the tweeter is clearly third order.
The cross to the lower woofers for BSC is second order.
Now a second order filter at 100 Hz is going to have a very high resistance inductor, and that will be enough to significantly raise the total Q of those drivers, because of the series resistance of the coil in series with the voice coils.
The other problem is that doing this is going to create a significant phase issue between the woofer sets. As the phase shift of the fourth order low pass filter will be 180 degrees, and the phase shift of the second order low pass will be 90 degrees.
You can clearly see the effect of this in your horizontal polar map between 300 and 500 Hz.
You also see it in the FRs, with bass reinforcement at the lowest frequencies, a null between 400 and 500 Hz and then a rise between 500 and 800 Hz.
As you probably know I'm not a fan of very low frequency passive crossovers because of these sort of issues. I'm surprised you did not hear these irregularities, even though the are likely a little subtle.
Your point about the problem of integrating these speakers with a sub is very well taken. If you cross these speakers at 80 or 60 Hz, then with that narrow spread between the two crossovers, the band pass gain will be horrendous. These speakers will not be sub friendly at all.
The design choice here seem to me strange, and frankly unwise, given current customary applications.