• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

2 way passive speaker on its side as a center channel?

Smitty2k1

Active Member
Joined
Jan 27, 2022
Messages
276
Likes
229
Are there any particular problems taking a standard 2 way bookshelf speaker and laying it on it's side to use as a center channel under a screen? Presumably the tweeter should also be rotated if not a dome?
 

Kal Rubinson

Master Contributor
Industry Insider
Forum Donor
Joined
Mar 23, 2016
Messages
5,273
Likes
9,789
Location
NYC
Yes. It will provide uneven dispersion off the central axis. 2-way horizontal arrays are problematic and asymmetric 2-ways are worse.
 

voodooless

Grand Contributor
Forum Donor
Joined
Jun 16, 2020
Messages
10,226
Likes
17,805
Location
Netherlands
Yes. It will provide uneven dispersion off the central axis. 2-way horizontal arrays are problematic and asymmetric 2-ways are worse.
They are actually not worse than a horizontal MTM. This is a decent 2-way on its side:
index.php

vs an MTM Center
index.php

Yes, the symmetry is better with the MTM, but the general outlook is definitely not.

An MTM is a worse compromise than a sideways 2-way.
 
Last edited:

DVDdoug

Major Contributor
Joined
May 27, 2021
Messages
2,920
Likes
3,831
Presumably the tweeter should also be rotated if not a dome?
You shouldn't have to rotate it unless it's a rectangular horn. ;)

...I don't remember the brand* but there is a 3-way monitor where the midrange and tweeter are mounted on a circular plate that can be rotated. The woofer doesn't get adjusted but presumably the longer wavelength is not a problem.

The problem with the woofer & tweeter being side-by-side is that at the crossover frequency both drivers are putting-out the same soundwaves. That's OK straight-ahead but as you move to the side the distance between the drivers creates a time-difference (one driver is closer to your ears than the other) and the waves can be out-of-phase at your ears and cancel.

The same thing would happen with the speaker oriented normally and you climb up a ladder... It can happen to some extent when you stand-up or sit-down.

It's usually not terrible, especially if it's only the center, and you probably won't notice anything unless you move across the room. Even then you probably won't notice anything with 5 or more speakers putting-out sound at the same time.


* P.S. Found it!
 
Last edited:

Mark_A

Active Member
Joined
Jun 28, 2022
Messages
131
Likes
26
If you had a 2-way MTM bookshelf speaker, you could turn that on its side and get fairly decent imaging.
 

sarumbear

Master Contributor
Forum Donor
Joined
Aug 15, 2020
Messages
7,604
Likes
7,314
Location
UK
An MTM is a worse compromise than a sideways 2-way.
An MTM is not a compromise, it’s simply the wrong design for the job a centre speaker. It’s shocking and a great shame that the entire industry is fooling the market. It’s not different to dieselgate scandal of the German car manufacturers.
 

sarumbear

Master Contributor
Forum Donor
Joined
Aug 15, 2020
Messages
7,604
Likes
7,314
Location
UK
If you had a 2-way MTM bookshelf speaker, you could turn that on its side and get fairly decent imaging.
No you don’t!
 

wwenze

Major Contributor
Joined
May 22, 2018
Messages
1,284
Likes
1,827
Maybe somewhere during the sound mixing lesson the students are taught to treat the center speaker as a beam that does not intersect with the wavefronts from the L/R

I can see something like this might actually work if the distance between the woofers are small enough compared to the wavelength. 2.5kHz is 14cm so maybe it is possible?

Mint-Hi-Performance-ENERGY-Encore-1HB-Center-Channel-Speaker.jpg


Of course going 3-way with a mini "upright bookshelf" section using a 3-inch woofer to minimize height will ensure the bigger woofers have enough wavelength
center-blog.jpg
 

Kal Rubinson

Master Contributor
Industry Insider
Forum Donor
Joined
Mar 23, 2016
Messages
5,273
Likes
9,789
Location
NYC
They are actually not worse than a horizontal MTM. This is a decent 2-way on its side:
index.php

vs an MTM Center
index.php

Yes, the symmetry is better with the MTM, but the general outlook is definitely not.

An MTM is a worse compromise than a sideways 2-way.
Ok. You got me but I don't believe that the OP had anything like this in mind.
 

ta240

Major Contributor
Joined
Nov 7, 2019
Messages
1,357
Likes
2,653
I've been going through the center channel search.
The SVS 3-way shown above measures quite well.
The Ascend Audio Sierra-LX is very rare in that it measures quite well on its side and is likely what I will go for, due to positioning constraints that make the SVS not work. My only fear is that I will want 2 more of the Sierra-LXs.

An MTM is not a compromise, it’s simply the wrong design for the job a centre speaker. It’s shocking and a great shame that the entire industry is fooling the market. It’s not different to dieselgate scandal of the German car manufacturers.

I'm still surprised by the number of more expensive center channels that are 2 way MTMs. I get the cost and look constraints of the $500 and lower ones; but near and above $1000 it just seems wrong not to do a decent 3-way.

Sierra-LX laying on its side:
Sierra_LX_Contour_Plot_Horizontal_Orientation.jpg
 
Last edited:

Neuro

Member
Joined
May 23, 2019
Messages
62
Likes
86
Location
Sweden
With two speakers next to each other in the horizontal plane at azimut 0 will be perceived as one sound source provided that the speaker elements are less than 25 cm apart according to "the summing location principle".

‘‘Summing localization’’ refers to a delay ~0–1 ms! when the sounds from the lead and lag sources are perceptually fused and when both the lead and lag contribute to the per-ceived direction of the fused image
(2) (PDF) The precedence effect
. Available from: https://www.researchgate.net/publication/12770632_The_precedence_effect [accessed Jul 18 2022].
 

sarumbear

Master Contributor
Forum Donor
Joined
Aug 15, 2020
Messages
7,604
Likes
7,314
Location
UK
With two speakers next to each other in the horizontal plane at azimut 0 will be perceived as one sound source provided that the speaker elements are less than 25 cm apart according to "the summing location principle".

‘‘Summing localization’’ refers to a delay ~0–1 ms! when the sounds from the lead and lag sources are perceptually fused and when both the lead and lag contribute to the per-ceived direction of the fused image
(2) (PDF) The precedence effect
. Available from: https://www.researchgate.net/publication/12770632_The_precedence_effect [accessed Jul 18 2022].
The precedence effect is about the localisation of sound in a reverberant environment. We are talking about frequency response versus angles away from the perpendicular to the speaker front baffle.

Not even remotely related.
 
OP
S

Smitty2k1

Active Member
Joined
Jan 27, 2022
Messages
276
Likes
229
You shouldn't have to rotate it unless it's a rectangular horn. ;)

...I don't remember the brand* but there is a 3-way monitor where the midrange and tweeter are mounted on a circular plate that can be rotated. The woofer doesn't get adjusted but presumably the longer wavelength is not a problem.

The problem with the woofer & tweeter being side-by-side is that at the crossover frequency both drivers are putting-out the same soundwaves. That's OK straight-ahead but as you move to the side the distance between the drivers creates a time-difference (one driver is closer to your ears than the other) and the waves can be out-of-phase at your ears and cancel.

The same thing would happen with the speaker oriented normally and you climb up a ladder... It can happen to some extent when you stand-up or sit-down.

It's usually not terrible, especially if it's only the center, and you probably won't notice anything unless you move across the room. Even then you probably won't notice anything with 5 or more speakers putting-out sound at the same time.


* P.S. Found it!
What about a ribbon tweeter? Would you rotate that?
 

luft262

Senior Member
Joined
Mar 25, 2021
Messages
465
Likes
236
Location
Phoenix
An MTM is not a compromise, it’s simply the wrong design for the job a centre speaker. It’s shocking and a great shame that the entire industry is fooling the market. It’s not different to dieselgate scandal of the German car manufacturers.
If a person directly on axis are there still problems for that person with an MTM design?
 

sarumbear

Master Contributor
Forum Donor
Joined
Aug 15, 2020
Messages
7,604
Likes
7,314
Location
UK
If a person directly on axis are there still problems for that person with an MTM design?
Most likely know but I have never heard of a one person theatre.
 

luft262

Senior Member
Joined
Mar 25, 2021
Messages
465
Likes
236
Location
Phoenix
Most likely know but I have never heard of a one person theatre.
I know. But some people might have a small family and/or only a spouse who either doesn't care about the audio or basically sits on axis anyway. I just wanted to know if there were tertiary issues with mtm other than off axis. Some people might even live alone and not care about other seats, but still have surround sound. For them the on axis response might be basically all that matters...
 
Top Bottom