• Please note that there are a few updates and clarifications made in the Audiokarma Rules, mostly relating to advertising and the addition of the new "Paying it Forward" & "Giving back" forums in the AudioKarma Audio Marketplace section.

Any Acoustic Suspension AND MTM options?

B

brodgers10

New Member
I am reaching out to see if anyone is aware of a currently produced speaker that utilizes BOTH "acoustic suspension" design and a D'Appoltio (MTM) configuration. I'm looking for true acoustic suspension, not just a sealed cabinet. Anyone know of such a beast, at any price level?
 
Register to hide this ad
NHT 3.3. 4 way design, and rather huge. I’m still incorporating mine into the room. 2.9‘s are more manageable in size.

The 3.3 have an in room response down to 23 hz and are nicely balanced.
 
A23gt said:
NHT 3.3. 4 way design, and rather huge. I’m still incorporating mine into the room. 2.9‘s are more manageable in size.

The 3.3 have an in room response down to 23 hz and are nicely balanced.
Click to expand...
I guess I would argue that the NHT 3.3's don't have a true MTM layout and are sealed, but not acoustic suspension. I believe their "C" line is where they have utilized acoustic suspension (but it is not MTM). I reserve the right to be dead wrong about all things!
 
brodgers10 said:
I guess I would argue that the NHT 3.3's don't have a true MTM layout and are sealed, but not acoustic suspension. I believe their "C" line is where they have utilized acoustic suspension (but it is not MTM). I reserve the right to be dead wrong about all things!
Click to expand...
The 3.3 are acoustic suspension. The internal volume of 1259 driver chamber is 2.78 cubic ft. Smaller than is optimal sealed design, but great for using the air mass in the box.

Other than not having as high of a frequency range it is just as good as an AR9 driver. It doesn’t go high enough to be a suitable AR 12 in replacemen.

They did something similar with the upper bass and mid driver. The driver arrangement is midrange driver followed by an offset tweeter and and then the upper bass drive. All drivers are in their own enclosures.

It could be argued that they aren’t MTM because of it only having one mid driver, but definitely acoustic suspension.

Ken Kantor had a lengthy interview where he spoke about the additional cost of manufacturing a driver suitable for acoustic suspension designs.

1259 specs.
THIELE/SMALL PARAMETERS
Effective cone diameter d: 20.00 cm
Maximum linear excursion Xmax: 1.30 cm
Resonant frequency F0: 19.00 Hz
Equivalent volume Vas: 190.00 L 6.71 cu. ft
Mechanical Q Qms: 2.60
Electrical Q Qes: 0.56
Total Q Qts: 0.46
Reference efficiency n0: 0.22 %
Output level< SPL: 85.52 dB SPL
Effective area Sd: 507.00 sq. cm
Maximum displacement Vd: 408.41 cu. cm
Krm: 28.89
Kxm: 26.67
Erm: .584
 
I found the RBH Sound 8300. Do we think that makes the cut? Some literature says it’s AS. However, it looks like there may be ports in the back. Is it possible that just the upper and mids are AS, while the bass is ported/vented?
 
Tweeters and mids in many modern speakers don't seem to need cabinet volumes at all, so they're closed back. That doesn't make them AS.
 
gkimeng said:
The NHT 3.3 is not a currently produced model.
Click to expand...
No, it’s relatively old speaker, but a valid option on the used market if you have the space and room layout for them.

I don’t know of any currently produced acoustic suspension designs that aren’t very high end boutique products.
 
Last edited:
gkimeng said:
Tweeters and mids in many modern speakers don't seem to need cabinet volumes at all, so they're closed back. That doesn't make them AS.
Click to expand...
Agreed, but when you look at the vas, q, and cabinet volume of the drivers (minus tweeter) it’s pretty clear that the NHT 3.3 design is acoustic suspension.
 
Taken from the specs posted in Stereophile

NHT 3.3 loudspeaker Specifications​

Sidebar 2: Specifications
Description: Four-way, sealed-enclosure, loudspeaker system. Drive-units: 12" polymer-cone woofer, 6.5" polymer-cone midbass, 4" polymer-cone upper midrange, 1" fluid-damped aluminum-dome tweeter. Crossover frequencies: 100Hz (12dB/octave), 320Hz (12dB/octave), 3.5kHz (18dB/octave). Frequency response: 23Hz-26kHz ±2dB (in-room, 1m). Usable bass response: -6dB at 19Hz, in-room (-3dB at 22Hz, in-room). Sensitivity: 87dB/2.83V/1m. Nominal impedance: 6 ohms (4.3 ohms minimum, 10.5 ohms maximum, no phase angle greater than ±30 degrees). Amplifier requirements: 30-300W, 1000W peak.
 
New acoustic suspension speakers in any form are rare birds today. You're probably going to have to give up either acoustic suspension or MTM.
 
gkimeng said:
New acoustic suspension speakers in any form are rare birds today. You're probably going to have to give up either acoustic suspension or MTM.
Click to expand...
They are hard to find. But, that’s the fun of this challenge. If it were easy, everyone would be doing it!! ;)
 
Human Speakers still makes acoustic suspension designs. This is as close as he comes to an MTM configuration. The rest of his work is updated EPI and Genesis.

www.humanspeakers.com

HUMAN Speakers: Model 8841

HUMAN Speakers builds new speakers and DIY kits in the USA, offers a full range of speaker repairs, and in-depth support for Genesis Physics and EPI/Epicure models.
www.humanspeakers.com
 

Attachments

  • IMG_0060.jpeg
    IMG_0060.jpeg
    74.4 KB · Views: 3
RVT1K said:
Taken from the specs posted in Stereophile

NHT 3.3 loudspeaker Specifications​

Sidebar 2: Specifications
Description: Four-way, sealed-enclosure, loudspeaker system. Drive-units: 12" polymer-cone woofer, 6.5" polymer-cone midbass, 4" polymer-cone upper midrange, 1" fluid-damped aluminum-dome tweeter. Crossover frequencies: 100Hz (12dB/octave), 320Hz (12dB/octave), 3.5kHz (18dB/octave). Frequency response: 23Hz-26kHz ±2dB (in-room, 1m). Usable bass response: -6dB at 19Hz, in-room (-3dB at 22Hz, in-room). Sensitivity: 87dB/2.83V/1m. Nominal impedance: 6 ohms (4.3 ohms minimum, 10.5 ohms maximum, no phase angle greater than ±30 degrees). Amplifier requirements: 30-300W, 1000W peak.
Click to expand...
Neither here nor there since the OP is looking for new, but this is taken directly from the owners manual, (Attached just in case someone needs one.

Model 3.3 Technical Specifications
• System Type: 4-way acoustic suspension design, Focused Image Geometry • In-Room Response at 1M: 23Hz - 26KHz, +/- 2dB, typical
• In-Room Response at 2M: 23Hz - 26KHz, +/- 4.5dB typical
• In-Room Low Frequency Cutoff: 22Hz at 3dB
• In-Room Low Frequency Useful Limit: 19Hz at 6db
• Distortion at 87dB SPL: <0.4%, 35Hz to 20KHz; <2.5%, 20Hz to 35Hz
• Distortion at 97dB SPL: <1.1%, 45Hz to 20KHz; <6%, 20Hz to 45Hz
• Sensitivity: 87dB (2.83V at 1M)
• Impedance: 6 ohms nominal, 4.3 ohms minimum, 10.5 ohms maximum, no phase angle over +30°
• Recommended Amplifier Power: 30 Watts to 300 Watts per channel, 1000W peak input
• Inputs: 1 pair of gold-plated 5-way binding posts for woofer input 1 pair of gold-plated 5-way binding posts for mid / high input
• Weight: 123 Ibs. each
• Dimensions: 42"H x 7"W x 31 "D, not including grille or stabilizer kit
• Finish: Italian black satin laminate, high-gloss mahogany or sycamore laminate
 

Attachments

A23gt said:
Human Speakers still makes acoustic suspension designs. This is as close as he comes to an MTM configuration. The rest of his work is updated EPI and Genesis.

www.humanspeakers.com

HUMAN Speakers: Model 8841

HUMAN Speakers builds new speakers and DIY kits in the USA, offers a full range of speaker repairs, and in-depth support for Genesis Physics and EPI/Epicure models.
www.humanspeakers.com
Click to expand...
The human speakers are nice, and sound very good from what I have heard. However, not a true MTM even with the slight nod to D’Appolito’s design
 
brodgers10 said:
The human speakers are nice, and sound very good from what I have heard. However, not a true MTM even with the slight nod to D’Appolito’s design
Click to expand...
Yeah, I knew it wasn’t MTM, just as close as Huw got with his designs. You really have a tough selection criteria. You would think someone would make a true MTM acoustic suspension loudspeaker. I would think there would be a market for one.

There’s one more out there making trues acoustic suspension designs. Can’t remember who it is. They were crazy expensive and I don’t think they were MTM. If I remember who it was I’ll check to see if they have a true MTM and post a link.
 
You must log in or register to reply here.
Back
Top Bottom