Upscale MTM?

[KEW]

The Appolito (sp) mtm design is supposed to offer significant benefits.
Certainly the most familiar example around here is the Ascend 340.
However I can not think of other (bookshelf speakers) examples among more upscale offerings. Ascend abandons mtm for all of it's Sierra line.
Is the "too tall" aesthetic of the mtm design to blame?

 

[GranteedEV]

THey're very often marketed as centers:

 

[Swerd]

The Appolito (sp) mtm design is supposed to offer significant benefits.
Certainly the most familiar example around here is the Ascend 340.
However I can not think of other (bookshelf speakers) examples among more upscale offerings. Ascend abandons mtm for all of it's Sierra line.
Is the "too tall" aesthetic of the mtm design to blame?

Don't forget the Salk SongSurround II.

http://www.salksound.com/songsurround overview - pricing.htm

 

[j_garcia]

Noticeable bump in sensitivity in most cases and additional midrange output thanks to two drivers covering the same range. I've always loved my GR A/V-2s. I think I'm pretty close to selling them though...

 

[zieglj01]

Also, Parts Express has one
https://www.parts-express.com/dayton-audio-rs722cml-speaker-curved-maple-left--301-977l

https://www.parts-express.com/dayton-audio-rs722cmr-speaker-curved-maple-right--301-977r

 

[zieglj01]

Also, Triad
http://www.triadspeakers.com/products/irslcr.html

 

[psbfan9]

Upscale MTM? No one does it better than Phil Bamberg;

http://www.bambergaudio.com/

The Bamberg 6 is a gorgeous speaker.

Bamberg 6

http://www.bambergaudio.com/products/series6/6mtmw.php

Bamberg 5 MTM

http://www.bambergaudio.com/products/series5/5mtm.php

 

[psbfan9]

I don't know if it has been mentioned here but PSA is now making MTM speakers. Not sure if they would be considered 'upscale', but the price is certainly up. $799.50 each.

Almost $2400.00 for L/R/C

http://www.powersoundaudio.com/products/mtm-210

And the matching center;

http://www.powersoundaudio.com/products/mtm-210c

• 2 way, audiophile loudspeaker
• 1" titanium compression driver
• Cast aluminum exponential horn
• Dual 10" high efficiency woofers
• Audiophile grade crossover completely designed in house
• Frequency Response = 70Hz - 20kHz
• Sensitivity = 98dB 1W/1M
• Size HxWxD = 28" x 11" x 16" (includes grill)
• Weight = 55lbs

 

[KEW]

• 2 way, audiophile loudspeaker
• 1" titanium compression driver
• Cast aluminum exponential horn
• Dual 10" high efficiency woofers
• Audiophile grade crossover completely designed in house
• Frequency Response = 70Hz - 20kHz
• Sensitivity = 98dB 1W/1M
• Size HxWxD = 28" x 11" x 16" (includes grill)
• Weight = 55lbs

Now that is interesting!
Dual 10" drivers and the FR only goes down to 70Hz. There must be something unconventional about this design.
Normally you would expect they had great bass, but would have a hard time playing the highs to properly cross-over to a 1" tweeter. The fact it only get down to 70Hz makes me less skeptical about the crossover issue.

 

[TLS Guy]

Now that is interesting!
Dual 10" drivers and the FR only goes down to 70Hz. There must be something unconventional about this design.
Normally you would expect they had great bass, but would have a hard time playing the highs to properly cross-over to a 1" tweeter. The fact it only get down to 70Hz makes me less skeptical about the crossover issue.

You could tell that speaker would not have good bass from one spec alone, and that is the 98 db sensitivity.

As I have explained many times here there is an inverse relationship between sensitivity and bass extension. The only way to put this right is to use a large and efficient horn to bring up the bottom end. You can not make a compact high sensitivity speaker and expect bass extension.

As far as MTM, as in all things there are advantages and disadvantages. The big advantages are increase in power handling and excellent horizontal dispersion while limiting vertical dispersion. The dispersion pattern is in many ways ideal as it limits floor and ceiling reflections, which are a major problem.

This leads to a disadvantage as you need to make sure the speaker will be used in a dedicated listening room were the occupants will be seated and the tweeter at ear level, or close. Varying the vertical height of the listeners changes the spectral balance.

The other issue, is that to make a good MTM design adds another constraint to the designer, as the crossover order needs the correct tilt, so that the axis of the upper speaker and tweeter has downward tilt and the lower driver and tweeter have upward tilt. This is very important as this produces a very focused and coherent sound stage. Unfortunately there are far too many designers who do not know how to design an MTM speaker properly.

I personally like the MTM concept in the correct situation.

The frequent use of the MTM on its side for a center speaker is the worst of all worlds with limited horizontal dispersion and maximal vertical dispersion. This is not what you want for clear dialog in most rooms. To compensate these designs have a degree of shout added which I can't abide. I find the vast majority of commercial center speakers on offer very sorry affairs.

 

[Swerd]

I forgot this one, Salk HT-2 in a 22" tall, sealed, stand mount cabinet. http://www.salksound.com/ht2 - home.htm. It uses the same drivers as in the floor standing version, the HT-2TL.

Salk also sells floor standers similar to the HT2-TL but with smaller footprints, using smaller Seas Excel mid woofers, the W16 (Veracity ST) and the W15 (Supercharged SongTower). I guess Salk could build these designs as MTM stand mounts.

They all use 4th order LR crossovers, which offer symmetric vertical lobe patterns.

 

[GO-NAD!]

I've been curious about how these perform, as the concept looks unique. That said, I'm not sure if they're still in production...they look great though.

http://www.energy-speakers.com/products/reference-connoisseur/?sku=RC-LCR

 

[zieglj01]

I've been curious about how these perform, as the concept looks unique. That said, I'm not sure if they're still in production...they look great though.

http://www.energy-speakers.com/products/reference-connoisseur/?sku=RC-LCR

You can see both horizontal and vertical measurements here,
as you scroll down
http://www.soundandvision.com/content/energy-reference-connoisseur-rc-70-surround-speaker-system-measurements

 

[KEW]

What is the effect of offsetting the tweeters from the center-line??

 

[Alex2507]

What is the effect of offsetting the tweeters from the center-line??

Let me give you my uninformed understanding of the matter. A tweet centered on the baffle would have two identical reflections of frequencies that would result in a larger bump on a graph at the affected frequencies. I think it's the same reason you wouldn't want symmetrical bracing for an enclosure.

 

[Rickster71]

What is the effect of offsetting the tweeters from the center-line??

The offset tweeter also works better when that speaker is used horizontally as a center channel.

 

[Swerd]

Alex got real close.

High frequency sound coming from tweeters will interact with cabinet edges, causing small peaks and valleys in the frequency range of about 4 to 8 kHz. The exact frequencies are determined by the distance from the tweeter to the cabinet edge. This is called diffraction, and in effect, it creates new points of origin for sound in addition to the tweeter.

If the tweeter is centered in a tall narrow cabinet such as in many MTMs, there will be two identical tweeter-to-edge distances, with identical diffraction peaks and valleys that add up. If the tweeter is slightly off center there will be two slightly different tweeter-to-edge distances. They may generate more peaks and valleys than with a centered tweeter, but because they are at differing frequencies and won't add up, they will each be smaller in amplitude.

Dennis Murphy always prefers off-set tweeters in his designs because he can easily see the difference in his measurements. He is not certain that this makes an easily audible difference, but off-set tweeters are easy to make at no extra cost during construction, so why not do it.

The exceptions are speakers like the Philharmonic 3 or the Salk HT1 & HT3 where the tweeters are centered, but the cabinets are not rectangular, and the front baffles don't have parallel edges.

So, off set tweeters can make a measurable difference in a single speaker in mono. What happens in stereo? Are off-set tweeters better toward the outside or the inside? People wonder and argue which is better. I doubt if it makes any difference. Take your pick.

Edit: This explanation is, of course, an oversimplification. A longer discussion of cabinet edge diffraction can be read here http://www.salksound.com/wp/?p=160#more-160.

 

[psbfan9]

Let me give you my uninformed understanding of the matter. A tweet centered on the baffle would have two identical reflections of frequencies that would result in a larger bump on a graph at the affected frequencies. I think it's the same reason you wouldn't want symmetrical bracing for an enclosure.

Alex got real close.

High frequency sound coming from tweeters will interact with cabinet edges, causing small peaks and valleys in the frequency range of about 4 to 8 kHz. The exact frequencies are determined by the distance from the tweeter to the cabinet edge. This is called diffraction, and in effect, it creates new points of origin for sound in addition to the tweeter.

Edit: This explanation is, of course, an oversimplification. A longer discussion of cabinet edge diffraction can be read here http://www.salksound.com/wp/?p=160#more-160.

So does this 'offsetting' of the tweeters create a definite left and right and as far as placement?

 

[KEW]

The offset tweeter also works better when that speaker is used horizontally as a center channel.

Do you know why it works better?
I was thinking horizontal dispersion might be slightly improved since it is not quite as "trapped" between the mid-woofers.

 

[zieglj01]

So does this 'offsetting' of the tweeters create a definite left and right and as far as placement?

Did you test different placements with your Definitive Studio Monitor speakers?
They do have off-setting tweeters.