If you own quality monitor speakers you want to read this new review

Hey rauliruegas,

I would be more then happy to discuss why your analysis of IMD is not correct, if you want to Email through AudioGon.

What I really want to share is that two more listeners brought their monitor speakers to my home to hear them with the NSMT band-bass subwoofer platforms and both were totally enthralled with the combination! Both want to purchase a pair in the near future. When I asked them what they heard that was an improvement both had similar remarks: 1) Can't believe the vast sound-staging with a sense of the original recording venue as part of the over-all perspective. 2) Not just bottom end extension, but a sense that the foundation of the music was much more there, but perfectly blended with the mid-range in a seem-less fashion.

Very high IMD.

Dear @amorstereo :There are some critical issues in that set up that are wrong:

first is that any two way speakers with concentric tweeter or not and running in its full frequency range develops very Intermodulation Distortions and this means that midrange/hig frequencies quality performance is non-adequated.

The main target when using subwoofers with those kind of monitors is to lower that high IMD using a high-pass filter to liberate the monitors of bass frequency response from 80hz and down and at the same time to have a true excellent bass range performace, this bass range is the foundation of the Music system reproduction and as better the bass range of the system as better its overall quality performance.

That " band-pass " kind of set up does not avoid that developed IMD and even makes it worst with added bass unit crossing as band-pass and I say bass unit because that is not a true subwoofer.

I'm using two true subs and I have first hand experiences on what I say.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

alanhuth is correct. Don’t believe anything unless there is a direct comparison. I could describe Apple air pods and good detail, excellent soundstage and imaging. Good bass but but a little warm and lacking depth. Easy to setup and great build quality, fits in your pock wow amazing, new standard…..
I could describe a pair of grado e225 headphones as bright, poor build uncomfortable, lacking deep bass.

Now compare these two and the Grado is better in every aspect of sound and not even close.
Without comparison there is no point. Even from memory is fine with me. I just look at pictures, price, conclusion and skim for a comparison. If there is no comparison in the review I just move on.

Hey jaudio1,
Thanks for the kind words towards my review. I would explain the hook-up this way, the monitor,regardless of which one you use, is directly driven by the main amplifier because the speaker wire goes directly into its terminals. Then, the jumpers connect the band-pass section with the full run monitor, which is driven and tuned by its own active amplifier and controls. Regarding, the matching of the veneers and the platforms: I can see some individuals getting them in a black finish that would look good and general support visually any color/veneer of the mounted monitor. However, the monitors I tested the platforms with were all walnut,except one which was gloss black, and looked great as a pair.

Tejay, in your review published review you mention that you had jumper cables made to connect the monitors to the sub.  So would it be correct to say that you connect your monitors to the sub and then connect the sub to your amp.  You set the crossover frequency, phase, volume in the sub.  If so, I can see why it is so easy to integrate.  Great review.  The only issue I can see is having the veneer of the sub not match the veneer of your speakers if your using another brand of monitor....could bother some people.

Well, their speakers seem to have some very positive reviews. They are very attractive to boot.But I’m not totally understanding why that sub would be superior to a couple of carefully set up conventional subs.I would love to compare and listen for myself though.

<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>

I did for MANY years. Look at my page you will see the "Band Pass" speakers (SAT "stack and test") right next to GRs servo SUB system. The 8" Band Pass MB (mid base) enclosures work PERFECT. It can go 3 tiers high with 9 drivers per column, for 10 foot or higher lids.

The difference with my set up it is VERY directional. 100hz to 300hz is VERY musical. It’s also VERY directional. It is not OMNI present like 80hz and below, SUBS.

THAT is the difference when you separate the two. I been preaching this for over 4 years HERE I been doing it to one degree or another for over 25 years. NO BASS of any kind in the monitor enclosure. Separate the Mid Bass from the Sub system, ALSO.

MB and SUB do not do the same thing or ACT the same WAY...

The actual distortion is BELOW 5% in the bass region 300 hz <. NOW
Mids and highs, will NEVER hit 1%. NOW

With Narrow baffles, phase plugs (to eliminate BACK WAVE distortion), narrow planars with ZERO enclosure issues (like cone driver), we can time align the enclosures to the room with height, location and to each other at the drivers seat. We’re talkin’ The Pinnacle of Precision and flexibility in just about any environment. up to 25,000 cubic feet. Total Immersion, not just a frontal assault so to speak. :-)

Did I mention a reduction in room treatment by 1/2 and 1/2 again by going kitty corner..

It eliminated BASS everywhere in my case the neighbors swimming pool. It went from WAVES to a little trimmer every now and then..:-)

I suppose IF I went with a single PS and a VERY good ribbon with a NARROW baffle I could get very close in a small room (less than 10 ft in any direction) and fewer drivers in the band pass. 1 driver per side could work, BUT the height of the BP driver is directional.. WHERE do you want it pointing? At your feet, your chest or your head.. It does make a BIG difference..

A small room (less than 10 ft in any direction) with BP enclosures is now a single 10" servo sub room.. No kidding it will smooth right out at the seated position.. THE HOUSE quits shaking because of so many sub enclosures, I think at one time I had 12 12" active drivers and 6 passives. I use a pair of dual 12" OB servo, its over kill, one would do it.. WITH MB columns and DSP.. I use 12K directly coupled to the drivers.. NO passive XOs. All active..
Cone control actually takes place NOW. It can't with passive XO.. Anything in the path.. NO CONE CONTROL for the overshoot.. only springs on the drivers..

It’s a good idea.. One of the better ones for the money and what they claim they do.. They actually WORK.. It was the 90s before British speaker new what BASS was much less SUB.. It didn’t exist their, did it?
Just kidding, kinda..

@dbphd asked, " What’s quasi-anechoic mean?"

Usually the term refers to loudspeaker frequency response measurements taken with a "gated" measurement system. This is a system which turns on the microphone long enough to capture the output from the speaker and then turns the microphone off before the first reflection arrives. This way the reflections are effectively excluded from the measurements without the room actually being anechoic, hence "quasi-anechoic".

The technique is only good down to the frequency where a whole wavelength can be captured before the first reflection arrives. So a different technique has to be used to get good data at longer wavelengths. John Atkinson of Stereophile close-mics the woofer(s) and port(s) at these longer wavelengths and then splices the curves together, and this is the most common technique.

Duke

I wish you and some of the others posters would read the details in the review regarding the differences between regular sub-woofers, like your 

OP LOL no one reads anything they just spew opinions, right or wrong. Welcome to the machine.

I think I’m at the point now where I don’t believe any first-person reviews of anything unless they are comparing A back-to-back with B and they have some pluses and minuses for each.

What's quasi-anechoic mean?  Isn't it more common to specify an environment as being anechoic to some frequency.

 An other thing I purchased the small container of Elixir contact enhancer  from the makers of High Fidelity cables. The stuff works. 
A friend came over who heard my system just prior to application..
Today he said we said there was more mid bass punch and apparent speed to the point I may not need my subs. The bass driver is the new and incredible 6.5 in from Purifi. Apparent noise and grit and grunge is much reduced with this treatment the highs are more coherent and articulate...and mid bass punch...is incredible. Tom

I am mostly retired now from being involved in the audio industry.
I ran a retail location of a small chain that sold Krell Threshold Thiel Martin Logan and Dunlavy. 
We also designed and installed custom car stereo systems including a band pass box designed by one of our installers that sounded really good. While the large 15 in subs would move the building they never had that mid bass punch that (The Terry Smith  Box) provided nor did the big woofers blend into the midrange like the bandpass 8s did. The preponderance of bass info is from 100hz and up..thats the punch and life of what we hear in most music.
The other big problem with larger woofers and their enclosure is the box itself is a passive radiator. So when you set your crossover point at 80hz..your box will have harmonics radiating acoustic energy into the room. The box design matters and is a major obstacle to articulate and clean bass. DSP may help in someways but there will always be harmonics that will interfere with midrange clarity. Interfering energy can always get in the way and become part of the intended music signal.
Tom

I would like to see a more rigorous explanation with data, graphs, etc. to confirm why this design is superior to a standard sealed or open baffle servo subwoofer.

Here is what the first review says:

“The cabinet design is unusual. It is constructed of ¾” formaldehyde-free MDF; top and bottom painted in satin black; front, back and sides veneered in black cloth. The driver is mounted horizontally on an internal shelf (which also braces the cabinet)—so the rear of the driver sees a sealed cavity. The front of the driver sees a tuned-port cavity and the front-firing port is 4.625” in diameter to minimize “chuffing” at high sound pressures. The upper—acoustic suspension—half of this design provides a better transient response than any ported cabinet; while the lower—ported—half of the design provides a passive 12 dB/octave bandpass filter. Unlike most designs, the 15EXP is not dependent on digital signal processing and will perform very well without it. The illustration shows its response curve without any electronic processing—it is flat within a few decibels within its passband. This is remarkable performance.

The main function of the internal amplifier is to eliminate an additional load on the system amplifiers—I am aiming at a “flat” response and have the subwoofer volume set about 15° from zero gain. The 15EXP has had a long evolution beginning before DSP became commonplace, and this acoustical heritage accounts in part for its ease of system integration. It is not designed to rattle the windows (although it certainly has that capability); it is designed to provide an unobtrusive, integral and natural extension to the frequency range of the main loudspeakers, and it does this without dependence on DSP. Mr. Ricketts writes that, “Without the electronic contouring of the frequency response most active subwoofers would be unlistenable...the 15EXP subwoofer achieves exemplary, linear frequency response primarily through the natural and harmonious mating of its high quality driver and its sophisticated bandpass cabinet design.””

http://v2.stereotimes.com/post/nsmt-armada-system-20m-monitors,--sandbag-stands,-15exp-subwoofers

I guess the editor will come in at some point and clean up your writing?       

" The pair shipped to me for review wherein a beautiful walnut hand-rubbed grain."
"I was feeling the psychical ambient air pressure waves as much as hearing the bass notes."

"So, suppose you love Harbeth Speaker's house sound and want to get very close to their $24,000 full-range reference, get one of their smaller monitors, and mount it on the NSMT pedestal for a lot less money! By the way. In that case, I have in-house two pairs of excellent subwoofers."
Etc.

Thanks for the link to the receive…
Wait!  There wasn’t one 😜😂😂

The real issue is how does it compare with the Model 100.  

Well, their speakers seem to have some very positive reviews. They are very attractive to boot.But I'm not totally understanding why that sub would be superior to a couple of carefully set up conventional subs.I would love to compare and listen for myself though.

No, no way am I adding any form of a subwoofer to my two channel hifi. Buy speakers that actually do bass, and avoid having to compensate with a sub. No better way to ruin the tonality, timbre,, and incentric characteristics of a particular speaker design. Big Tannoys do bass very well thank you.

Never mind, I found the article. 
What I like; I love the woodwork on the monitor enclosure. The coincident design of the monitor's driver is a great way to design a point source speaker and the woofer/mid cone serves to limit the dispersion of the tweeter which will decrease room interaction. With a first order crossover imaging should be excellent.
What I do not like (as if it really matters); The use of the term "bandpass" to describe the subwoofer which in reality is just a 10 inch driver in a ported enclosure limiting frequency response at the bottom and an active crossover limiting the frequencies at the top. It does not have a complete 2 way crossover so the midwoofer in the monitor is flapping around at low frequencies distorting everything else that driver is doing. An active 2 way crossover would improve the monitor's performance to a large degree.
The subwoofer is too small and light to be able to produce very low frequencies with authority. It's frequency response was taken near field and it could only make it down to  27 Hz. At 12 feet it will be lucky to make it down to 40 Hz. In reality it is a woofer, not a subwoofer. Using 4 of them in a swarm type system might produce better results.
IMHO the system is overpriced. 
Using high quality monitors with subwoofers below is an excellent way of putting together an excellent system at  very reasonable cost but the performance of the subwoofer can be no different than for any other type of main speaker. It is amazing how big a small monitor can get with the right subwoofer. We sold a pile of Rogers LS3 5As this way combining them with RH Labs subs and the Dahlquist DQ LP1 crossover. This was back in the late 70s!

amorstereo, can you supply us with a link?

My own system looks very similar, KEF LS50s sitting on top of REL T5is, a co-axial standmount sitting on a fast sub.

The best sub position was also the speaker position, the result glorious, a full range sound that is in phase with the superb imaging of the KEFs

I believe this is the article the OP is referring to.
http://v2.stereotimes.com/post/nsmt-loudspeakers-20m-armada-system-by-terry-london/

Maybe not relevant, but here is an older article about 20Ms.
http://www.stereotimes.com/Speak072711.shtml

A link would have been nice. 

Hey mijostyn,

Please read the review for the details/explanation you asking about. There is an extensive/detailed explanation by Erol Ricketts, the designer, that I requested he contribute to my review for the very reason you are asking your question.

Amorstereo, what is meant by "bandpass." Are you saying that the crossover in the pedestal is rolling off the bass to the monitors?  

Hey wolfie62,

Gezz, I wish you and some of the others posters would read the details in the review regarding the differences between regular sub-woofers, like your Velodynes, and how an acoustic band-bass design are not the same thing. Your subs use DSP to control certain frequencies, instead of loading the driver in an unique fashion in a ported box which leads to a very different loading of the room by the device. I have used excellent pairs of sub-woofers for years with monitor speakers with excellent results. However, they never reproduced the weight/foundation of the power region in the music and allowed the spatial cues to effect the sound-staging to evolve into a three-dimensional illusion that the monitors completely disappear in. I could allows "deal-in" the subs, no problem in my listening space(s) and they worked fine without mudding up the mid-range's timbres or clarity. The NSMT band-bass platforms are a different approach and deliver sonicly a vastly experience then a regular active sub-woofer. In the review I asked the designer, Erol Ricketts,to explain the differences and why he chose to use this design in this model.

My excitement over these platforms is that they just don't take a reference level monitor's performance and add bass extension, but transforms them into delivering in a way that usually is only done by large multi-driver floor-standing models without losing any of the tonal purity and sound-staging magic of small two-way designs.

I still use my Velodynes. Active, with DSP continuously variable high pass and low pass, volume adjust, contouring adjustment, and phase angle adjust, as well as remote control, to adjust from my listening position. 2005 15” DSL model. 
So this is an OLD idea. Nothing new here.

I’ve been using MB columns (active band pass 80-300hz) for 10+ years and GR servo bass (60-80hz and down) for 3 years. You call them Band pass, we called them Bass Bins. I had a pair of 500 lb 20 cf tri-pole Bins.

They were made for a dance floor. You could point a single pole UP or forward or against a wall or back to back the units in the center of a bowl venue. There use to be a lot of dancing on TOP of those speakers
around harvest time.. :-)

100 x 100 x 20 shop, they would pressure the whole thing..

Regards

Stand mounts are very good but cannot duplicate a live performance like A good 3  way speaker with a  minimalist Xover .
the open baffleSpatial  audio labs X3 comes to mind with the superb Beyma
horn loaded AMT tweeter- midrange,12 inch mid  bass driver , and powered bass from 90 hz down ,and  97db efficient.

I'm thinking that the "what ifs" are included in the review.But not having read it yet....

Right...

When I decide something is my favorite, I am always prepared to discuss why I am right. But, I prefer it if nobody tries to engage and point out anything other than how right I am....

Just positing "what if?"

Hey fuzztone,

Ran that experiment, monitors mounted on the NSMT platforms and placing the monitors on their own stands and placing the band-pass subwoofers where I normally have my sub-woofers placed, and the significant improvements still were apparent. Don't know if you read the review, but my process of evaluating the effects were extensive to come to my conclusions.

Then again may be just better speaker positions than sub positions in the room.