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How Bad are those MTM Center Speakers in Practice in Reality? Revel C25 Content Inside

Do we objectively make too much of horizontal MTM designs in real-world applications?

  • Yep

    Votes: 9 34.6%
  • Nope

    Votes: 17 65.4%

  • Total voters
    26

gbrnole

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A plot showing, say 25 degrees, is greater than +/- 18 degrees.
(I.e. You do not need to double the values as it is relative to being “off of the centerline”.)
yeah the total width in all listening positions across my seating area is 36 degrees (actually a hair under that) so 18 degrees from center to each of the left most and right most seating positions. for most of the MTM centers you are hard pressed to find anything that doesn't begin to have serious off axis issues beyond 10 degrees from center - 20 degrees total.

vertically the center speaker is 7.6 degrees below my ear level but i do tilt the front speaker and use a laser pointer to angle up towards ear level to negate that. i have about ten inches of height space to work with for the center speaker but that is reduced when the speaker is angled.

ideally i'd love to be able to use a revel c208 but i just don't have the space for that. a c25 or a c205 would fit comfortably but i would prefer a little larger woofer in the 6 to 6.5" range. i have pondered just grabbing a kef q350, laying it on its side and calling it a day. the only real downside to that is to get the most out of a q350 you need equalization in the higher frequency region so it leaves me a bit apprehensive. ARC genesis will smooth that region but it will also color the sound of the speaker in doing it.
 

Holmz

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yeah the total width in all listening positions across my seating area is 36 degrees (actually a hair under that) so 18 degrees from center to each of the left most and right most seating positions. for most of the MTM centers you are hard pressed to find anything that doesn't begin to have serious off axis issues beyond 10 degrees from center - 20 degrees total.
I ended up getting a used center channel
(+/- 40 degrees)

The center has one job, which is a wide radiation pattern.
The rest can be fixed with a DSP.

vertically the center speaker is 7.6 degrees below my ear level but i do tilt the front speaker and use a laser pointer to angle up towards ear level to negate that. i have about ten inches of height space to work with for the center speaker but that is reduced when the speaker is angled.

ideally i'd love to be able to use a revel c208 but i just don't have the space for that. a c25 or a c205 would fit comfortably but i would prefer a little larger woofer in the 6 to 6.5" range. i have pondered just grabbing a kef q350, laying it on its side and calling it a day. the only real downside to that is to get the most out of a q350 you need equalization in the higher frequency region so it leaves me a bit apprehensive. ARC genesis will smooth that region but it will also color the sound of the speaker in doing it.

Another nuance is that if the MTM is different from the L/R sides, then its sound may be out of phase with them in certain bands as the drivers can be out of phase.
Best to stick with the same brand IMO.
 
Last edited:

FrantzM

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Thanks, and for the record I’m still married. :)

Here is the back wall with panels having a 9cm air gap.

The room layout is not that good, but it is the only one that works.

View attachment 180284
Could you tell us more about the Acoustic treatments ? Front and rear...They look uber-cool :) >
Heck! Your entire room is beautiful :D . Congrats!
 

Trell

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Could you tell us more about the Acoustic treatments ? Front and rear...They look uber-cool :) >
Heck! Your entire room is beautiful :D . Congrats!

Thanks!

The panels are made by GIK Acoustics, EU subsidiary. The flat panels are 10cm (4”) thick, and all of them have scatter plates in order to not absorb so much HF. The flat panels on the back wall have an air gap of 9 cm. About 50% of the front and back wall is covered with panels.

The links below will redirect depending on your location.




 
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Colonel7

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What if I always get the center seat, and none of my family members care about any of this stuff?

What if my 9 year-old bounces around all over the place, and my wife falls asleep after 30 minutes of whatever we are watching?
Nice thread and thanks for the measurements in application. Based on this though, isn't the rationale that they don't know any better, or that they haven't heard a 3-way or coaxial, or that you won't give up the dad seat? Or it is in fact not a big deal? Maybe as an experiment for a few weeks you sit in one of the end couch positions, or during each movie at a specific time you play musical chairs and switch seats without pausing.

Very timely! Just finished the prototype cabinet today and time to start on the crossover. And if you look carefully please note the wall is a special new paint color called ASR brown. :cool:
20220202_141419.jpg
 

luft262

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Here are my 2 cents...

I think the main pros of a center channel over just using the mains would be better off axis sound quality and the ability to increase the volume of voices. Using a bookshelf might mess up the TV's position and it will look strange to anyone who doesn't frequent this site (lol!) and even some of those. Getting a center channel that doesn't match your mains might work OK, but might not. Timbre may or may not be a thing. I've had a system with a non-matching center, a system with a matching center, and my current system has no center. I can't really say how sound quality was affected, because I wan't comparing them back to back and it was years ago. I can say that having a center channel allows you to boost the volume of voices in movies and shows and my wife especially really likes that. When I watch movies alone I can crank it, but she usually likes dynamic volume on and the center channel turned up +3dB, or at least she did with our old system, since the center was available.

I guess if you have people who care about the sound sitting off center and/or if you have someone who wants the center turned up for voices then you'll benefit from a center channel. But unless you regularly have off axis listeners who actually care about audio the type of center channel won't matter much so I'm going to vote with "we're overthinking it!" I'll probably throw my hat in with getting the matching center channel to the mains for aesthetics if nothing else.
 

Descartes

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Too bad Erin didn’t include the C25 in his center channel shoot-out!

Amir’s position “Without EQ and for center usage, I can't recommend the Revel C25….”
 

Richard G

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In case anyone hasn’t seen it - Erin’s tests of eight centre channel speakers

Are there any websites - which? which have measured the HD (horizontal dispersion) of many centre speakers? Ideally in a standardised way

after seeing Erin’s plots, imo the easiest solution is - certainly a much wider choice - use a single bookshelf speaker (o course, one short enough to fit your space)
  • as (to my patchy knowledge) few centre speakers are measured at all, especially for HD (without having to spend time and risk estimating the correlation between the design and directivity) and
  • as there are so many more bookshelf speakers than HT-C
 

ryanosaur

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It still seems that there is (or should be(?)) a major element of expecting the Speaker Designers/Manufacturers to produce Speakers that will minimize any acoustic concerns as it regards the duty of said Speaker in producing a uniform directivity as free of deleterious effect as possible.
That said, I do agree that we tend to make more of the measurement aspect than what may account for pure audibility. In that act, however, also resides the idea of best practices...
(We know not to push a rear-ported speaker back into a cubby where it barely fits, has a closed back, etc. Rather, pull the Speaker forward so the baffle protrudes a slight bit in front of the furniture. If it has to in a cubby, we know an open back or a Sealed Speaker is better than a Ported... And so forth.)
On the other hand, what we have are companies putting (in many cases) Speakers to market which rarely adhere to best practices but do adhere to a pattern of inexpensive designs which usually take up very little space and don't perform as well as we may wish.

Are there several different market segments that some of these designs adequately match to? Absolutely!
I think the most difficult segment is the group that starts off looking for a bang-for-the-buck system, has little knowledge of good design principles or understanding of the engineering and physics behind the equipment, and then finds they are dissatisfied by their investment (either having been sold on a product by an undereducated sales person or through sheer ignorance on their own part).

We have seen many cases where educated consumers and fellow forum goers are quite happy with a horizontal MTM. While they have their academic issues, they aren't always horrible in practice.

FWIW, I used a BMR Monitor in horizontal fashion for a while and have since switched it to vertical. I couldn't identify any issues with it on it's side but knew it would be better upright (...you know, best practices! ;) ) Given the opportunity I will also remove all of my equipment from the front wall, leaving only my Phil3s, the BMR Monitor at Center, and the wall-mounted TV.

I fully appreciate @Steve Dallas ' efforts here. It reminds us that what we think of as best practice doesn't always matter in the way we expect it should. :) But that doesn't stop us from looking for the best gear for our respective budgets and fiddling incessantly with our own implementation until we are satisfied or get distracted by the next squirrel to run across our path.
 
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