Whatta Ya Think About Hsu Research Subwoofers?

I’m in the market to add one or possibly two subwoofers to my stereo set-up.  I would like to spend $1,000 or less per unit, and that puts some of the higher-rated units out of reach.  I came across an ad for Hsu, which I had not heard of before.  I didn’t want a Chinese product and it turns out that Hsu Research is based in California and founded by Dr. Hsu, who has a Ph.D from MIT.  Audio reviewer Steve Gutenberg gave one Hsu product a positive review.  I was wondering if any of you have experience with Hsu and could share your impressions/recommendations with me.

My existing set—up is:  Parasound P5 pre-amp with Parasound A21 amp;  Martin Logan 60XT tower loudspeakers.  Thanks!
Hello Bob,

     Forgot to mention, driving yourself crazy with this audio stuff is a choice and one I don't recommend.  I consider this audio and music hobby a journey and try to enjoy it along the way.

Keep it fun,
Tim, I am usually the sort of person who can window shop, see nice things and pass them by without stressing over not buying them.  But occasionally I get on a bent when I see something and think, “Someone else has this and is enjoying it, while I am stuck with . . . this.”  There is a audiophile-type stereo and home theater store not far from me, and I have thought, “Why don’t you just go and hear this equipment for yourself instead of reading about it or asking for others’ opinions?”  But then I fear that I will go there and hear or see things that are so excellent, but beyond my budget to afford, and then I return home and am thereafter dissatisfied with what I have.  I don’t feel that way when I see a fancy sports card or a palatial home, but I could see myself longing for an exquisite sound system. I could see myself obtaining some new music and enjoying it on my system, but then thinking, “I wonder what I am not hearing that would be revealed by that expensive gear I sampled the other day?” It can be a feeling of pleasure-denied.  
bob540  I bought 2 HSU ULS 15`s a couple weeks ago, still breaking in and they sound very VERY nice.
Curious...is '540' a BBC reference ? :)
Hello Bob,

     This is a direct quote from you on your post from 2/24/20: " There is space to the left, as I can move the tower that holds my CDs and the record albums. I wish I had Bluetooth capability for the subwoofers, as I could place one further to the right out of the line of foot traffic, and then I have space for one on the left. I could cover the cable with a small throw rug I suppose.
     Bob, the Syzygy subs are exactly what you wished for; Bluetooth capable subs that are wireless and let you use an IOS or Android smart phone as a remote. You can place one to the left of your rack and the other anywhere in your room without running any wires. No throw rug to cover the cables is needed since there are no wires or cables connecting the subs except a power cord for each to the nearest a/c outlet..
     They’re made in the U.S.and there are 2 versions which have either 10 or 12" drivers:
The Syzygy SLF850 utilize 10" drivers, have a rated bass extension down to 24 Hz and are priced at $799 +$60 shipping=$860 each on Amazon.
The Syxygy SLF870 utilize 12" drivers, have a rated deep bass extension down to 20 Hz and are priced at $999 +$50 shipping=$1,050 each on Amazon.
Here’s a link to both on Amazon:

I     f you’re serious about your wish for Bluetooth capable subs and attaining very good bass performance in your system, I suggest you begin with a pair of 12" SLF870 subs, which will provide very good bass at your designated listening seat down to 20 Hz.
     Then in the future when you’re ready, you could add a third 10" SLF850 sub, which will provide even higher quality bass quality not only at your designated listening seat down to 20 Hz but throughout your entire room. Even though only 2 of the 3 subs are reproducing deep bass down to 20 Hz and 1 sub just to 24 Hz, the overall bass will sound like it extends to 20 Hz in the room.
     This results because adding the third sub creates the necessary minimal number of subs in any given room to qualify as a distributed bass array (DBA) system. The 3-4 sub DBA system concept has been scientifically proven to modify the bass sound wave behavior in any given room in a specific manner that creates a bass sound wave environment that our brains process and perceive as the overall bass being fast, smooth, extended, powerful, dynamic, detailed, natural and seamlessly integrated with the main speakers.
     I realize this all likely sounds a bit confusing to you. In general, the 2 sub solution works well at a single designated listening position while the 3-4 sub DBA concept solution works significantly better, as in about twice as well, throughout the entire room and like a charm. An Audio Kinesis Debra 4-sub DBA system has been providing near state of the art bass performance, for both music and HT in my room and system, for over 5 years now and I see no reason it wouldn’t do the same for music in your room and system with a custom 3-sub DBA system provided the subs are properly positioned and configured (configured meaning the volume, crossover frequency and phase controls are all properly set on each sub, which I can assist you with).
     However, I think you need to decide whether you want to utilize and run line level cables to traditional self-amplified subs like the HSU or utilize the newer technology Bluetooth wireless subs like the Syzygy.
     There’s also a third option available, which is to buy a Dayton SA1000 1K watt class AB sub amp/control unit for $300-400 from Parts Express (which the AK Swarm and Debra 4-sub DBA kit systems utilize) and use 2-4 less expensive good quality new or used passive subs connected via speaker wires. You’d also be able to progress with this amp from using 2 passive subs in your room to using 3 or even 4 subs. The main downside is running and concealing the speaker wires to them.
    All 3 solutions will produce equally very good results with a pair of subs and will produce near state of the art bass results with 3-4 subs. I’m willing to assist you with any option you choose.
     It seems like the wireless Syzygy subs may be a bit more expensive, mainly due to the shipping charges, but they’re also a lot more convenient, especially in your room. Are you willing and able to run speaker wire or line level rca cables to other areas of your room to save some dough? Or, do you prefer convenience? Let me know.

scm:  Nothing special about 540.  It was just a number I tagged onto the end of my name to differentiate me from all the other Bob’s on a discussion forum.  Glad you are liking your Hsu’s — they look like nice subwoofers.

If I am considering Bluetooth subs, how about this one from Martin Logan.  12” drivers with Bluetooth capability, and they look similar to other models costing more (which doesn’t mean they sound as good . . Don’t know):