I find that to be a really good point.  Low volume leaves out some information.    
    On another related note, if I remember correctly, harmonics go both ways. So if there are harmonics from say a cello that reach beyond it's scale, then the obverse is true. And harmonics are weaker signal than the original.

Hi Lon,

Been meaning to post but been too busy listening or working. I've actually been getting up an hour early each morning just so I can listen for a bit. The Super Zen and Mid Bass Module combination have provided an audible window into what is really happening in the lower frequencies. This has allowed me to tweak the system some and actually hear the improvements.

Last week I changed to a different equipment rack I had on hand in an attempt to improve vibration control. In the process I found that my two sets of Decware 1/2 meter interconnects I had been using were a tad tight so I went to a couple 1 meter pair of pure silver interconnects I have had for a long time.

It was interesting, when I powered back up and started listening my first impression was the low end was just a tad thinner. After listening for a while it was apparent that the low end was not thinner but more accurate with more clarity. Kick drum and Bass Guitar notes for instance seemed to have more space between them. Less tendency to bleed together.

Now to your question. Per Steve Deckert's advice I use the speaker level connections so that the MBM is reproducing as close as it can the signature of the Super Zen amp. I'm actually using common Cat-5 computer network cable purchased from Lowe's. I know, does not sound very Hi-Tek but it sounds good. The cable has four twisted pair, each individual conductor is solid copper (not stranded). I always use bare wire speaker level connections at the amp, mains, and MBM. The solid copper conductors hold up better than the very fine stranded type.

I twisted two of the pair together for the POSITIVE and the other two pair for the NEGATIVE.  So basically I have one Cat-5 cable for the left channel and one Cat-5 cable for the right channel. I have a pair of MBM's so I run them in Stereo, left channel only to left MBM, right channel only to right MBM.

I have experimented with just one MBM where I run both speaker level channels into a single MBM and the single unit performs very well in my room. The MBM has speaker level input connectors for both left and right channels. It did seem when I switched back to dual MBM's (Stereo) that low end clarity was improved a bit but it was not a night and day difference. I have implemented a few other small system tweaks since then that might account for the difference at that time ??

I did have a small ground loop issue. I run dual MBM's and ULS-15 subs in stereo mode. So left channel for instance I run speaker level connection to the left sub and daisy chain to the left MBM. Seems the MBM's would interact with the sub it was mated to. I simply ran a Radio Shack test lead with alligator clips on each end from one of the steel toggle switches on the MBM to one of the toggle switches on the ULS-15 sub to give them a common ground.

I talked to Dr. Hsu about the ground loop. Basically they expect anyone not living in a cave these days will use the line level connection. I think they expect the ground on the line level interconnect to tie all the grounds back to the amp ??

After I got my Super Zen I could just barely hear a very low level hum with the MBM's turned ON. I had to be right up next to the mains to hear this. Not audible at the listening position or with the MBM's turned OFF. I tied the the ground jumpers installed between each MBM and sub back to the case of my surge protection device where everything is plugged into. Bam, everything was dead quiet and it made a noticeable improvement in low frequency playback. Again just seemed to be a little more separation and space between instruments on the low end.

It seems if you have any type of low level distortion from your source, pre or amp the MBM is going to make that audible. In my case that has been a good thing since I have been able to identify (hear) and address these things.

The biggest advantage of the MBM is that you achieve big, full, spacious, satisfying sound at low to moderate volumes. I've been trying for 20 years to achieve this type of sound in a listening room with subwoofers and have had limited luck at best. The MBM is not a subwoofer.

I've come to appreciate that subwoofers are more of a Sledge Hammer. They are designed to reproduce frequencies that you feel more than you hear. The MBM is more of Hammer, much more nimble, more subtle.

Thanks for that info! I think if I were to use these I'd use the line level inputs from the CSP2+ . . . I will even have one of those with an extra stereo out put which would work for two or one. I like the signature of the CSP2+ so much that thanks to Bill selling one here I bought another to use with my SACD player which doesn't sound quite as good just straight into the Torii Mk III. For me the ideal preamp is a CSP2+ with three or four inputs. . . .

Anyway, your experience is really informative and I have no doubt that you are enjoying excellent sound. I'm moving to a townhome in OHio soon and will have a few neighbors; I've been living in a house with some space between neighbors for twenty plus years. I may need to listen at lower volumes, and your experience shows these HSU units can be a big benefit.

Another thought: I really like the simplicity of the HSU products. None of the "Digital Signal Processing", "Servo Control", "Parametric Equalization" or any of that other CRAP that I have tried with only limited success at best.

Who would have Thunk It, simple amp, driver and enclosure that does exactly what they say it will do.

Pale Rider,

Thanks for turning me on to Paul McGowan's daily discussions over at PS Audio. I thought this kind of fit into the topic being discussed on this thread and should be shared:

http://www.pstracks.com/pauls-posts/loudness-button/9651/

Well put DBC, like you, I have been part of this Foum for 12 years with the purchase of my Zen Select SE84CS in May of 2001. I don't post that much either and I learn things from Poster's like Lon, whom I very much appreciate on this Forum.

Now, I'm learing from you. I am ordering a MBM soon as I finish this post! Furthermore, I have a pair of Klipsch RF 52 II coming on Monday from Crutchfield. $448.98 delivered....can't complain. I have bought them for my bedroom system. However, after a long breakin...I think they will make it in for an audition in the Listening Room System.

Anyway, back to the MBM....RF 52's come Monday and the MBM by the end of next week and I'll return with some early thoughts.

I will use the MBM-12 MK2 in my Listening Room System first...and then out with the Polk 1.2 bohemoths...then with the Bedroom System....burned in RF 52 II's down the road.

I will be purchasing just one (1) MBM...I do realize you have two. I will run 14 gauge wire to them from Super Zen CKC Speaker connections to Speaker connections of MBM....placing the MBM near me/Listening Chair.




Listening Room System (12 x 14 room):

Ipad2 with Apple LossLess/CD Error correction>Cambridge Audio iD100 Docking Station >Illuminati D-60/BNC>Audio Alchemy DTI-Pro32>Prophecy Cryo-Silver Reference i2s>Audio Alchemy DDE 3.0 w/remote wand>Kimber Select 1030>Decware SuperZen CKC Amp>Kimber Select 3033> Polk LS 90....Room Acoustically treated/Dedicated Room & Adcom ACE-515 AC Enhancer // Herbie's Halo's on all Tubes & 2.5lb Mapleshade Brass weight on top of CKC Transformer // XLO Pro Power Cord to SuperZen




2 Channel Home Theater (w/Polk SDA SRS 1.2 Speakers):
(DVD, Blu-ray disc, CD, Vinyl, HDTV & Sirius Sat Radio via Dish Network)

Panasonic Blu-ray>Kimber Hero IC>Rotel RA-1062/Pre-Amp>Kimber Timbre IC>Emotiva XPA-2/(300 watts per CH into 8 ohms)>Kimber 8TC Speaker Cable>Polk SDA SRS 1.2/(use SDA always)>Kimber PK10 Palladian Power Cord to Emotiva XPA-2

Dish Network/HD DVR with Kimber KCAG IC to Rotel RA-1062/Pre-Amp.....
Sharp 46' Aquos Quattron HDTV/extra thread of Yellow (2nd only to the Pioneer Kuro)

Pro-Ject Debut Carbon (Red Plinth) to Pro-Ject Phono Box II with Audio Quest Diamondback IC to Rotel RA-1062/Pre-Amp.....

Velodyne Subwoofer wired with Kimber 8TC out of Emotiva XPA-2
Soon to be replaced by: http://www.hsuresearch.com/products/vtf-15h.html .....(fall of 2013 purchase)




Bedroom System:
Pioneer DV-563A...Illuminati D-60...Cambridge Audio DacMagic...Kimber Silver Streak...Decware SE84CS (stock)...Zen Styx w/Silver plugs...Klipsch RF 52 II

Stone, I'm pretty sure you will love those Klipsch.  I gave my brother my old (1 yr. ) pair of rb81's to help out in his system.  I loved them...great bang for the buck and Crutchfield is a great co. to buy from.

JD