Floors & Ceilings aren’t Walls

[novisnick]

Thought I’d bring this discussion / beat down over to a proper thread. Thanks to the OP ( rossandwendy ) for your patience in the your thread. 👍 
I’m hearing and reading much, some from 11 years ago(thank God time and technology hasn’t changed a thing), anout horizontals vs vertical placement of center speakers and that MTM speakers just don’t cut it. 

From outside the box it seems that a premiss is made and then “proof” derived to make it seem so. I’ve seen it many times in every field of science, hence my reason for skepticism.

Facts are facts and I’ll prove any one you like with my statistics! 😋


This thread is not for bashing or fighting but a means to inform. My personal experiences have shown me that walls are ceilings and floors are walls. Sound moves at a given speed and timing is everything. What a mess absorbers and deflectors can make! 😁 Do it right and your golden, wrong and you’ll pull your hair out. 

[hemster]

Yeah! And walls are floors but not ceilings!


Unless you were at the party with me last weekend! 😛😁

[cgolf]

Any surface can impact sound, good or bad.

[509Paul]

[ÈlTwo]

Here's the proof of concept:

[DYohn]

All six surfaces in a room effect sound similarly, depending on the dispersion patterns of the drivers. Indeed, the wall to ceiling corners are the most overlooked in listening room design and can create standing waves in the same ways as any other corner. Bass traps in this area can yield better results than in the traditional wall-interface corners in some rooms.

The issue that is caused by horizontal MTM arrangements of traditional center channel speakers is called lobing (cancellation caused by two drivers reproducing the same frequency bands.) All MTM speakers, whether horizontal or vertical, are subject to this acoustic effect, but when aligned on the horizontal plane the effect is "across" the listening field rather than "up and down" through the field and is more likely to occur at the "ear height" of the listener. The impact of this can be distortion and reduced SPL in the critical vocal frequency bands, and is one reason why many home theater setups suffer from poorly understood vocals.


Using a center channel speaker is critical to proper HT performance, and using one aligned on the vertical axis generally yields the best results.

Using three "voice matched" speakers actor the front of an HT is critical to seamless sound location in relation to the action on screen, and using three identical loudspeakers yields the best results.

[emofrmcgy]

Aug 24, 2018 9:19:41 GMT -5 DYohn said:

All six surfaces in a room effect sound similarly, depending on the dispersion patterns of the drivers. Indeed, the wall to ceiling corners are the most overlooked in listening room design and can create standing waves in the same ways as any other corner. Bass traps in this area can yield better results than in the traditional wall-interface corners in some rooms.

The issue that is caused by horizontal MTM arrangements of traditional center channel speakers is called lobing (cancellation caused by two drivers reproducing the same frequency bands.) All MTM speakers, whether horizontal or vertical, are subject to this acoustic effect, but when aligned on the horizontal plane the effect is "across" the listening field rather than "up and down" through the field and is more likely to occur at the "ear height" of the listener. The impact of this can be distortion and reduced SPL in the critical vocal frequency bands, and is one reason why many home theater setups suffer from poorly understood vocals.


Using a center channel speaker is critical to proper HT performance, and using one aligned on the vertical axis generally yields the best results.

Using three "voice matched" speakers actor the front of an HT is critical to seamless sound location in relation to the action on screen, and using three identical loudspeakers yields the best results.

Do you have an evidence to support this ? It seems highly suspect that this is simply opinion.

[DYohn]

Aug 24, 2018 10:11:45 GMT -5 emofrmcgy said:

Aug 24, 2018 9:19:41 GMT -5 DYohn said:

All six surfaces in a room effect sound similarly, depending on the dispersion patterns of the drivers. Indeed, the wall to ceiling corners are the most overlooked in listening room design and can create standing waves in the same ways as any other corner. Bass traps in this area can yield better results than in the traditional wall-interface corners in some rooms.

The issue that is caused by horizontal MTM arrangements of traditional center channel speakers is called lobing (cancellation caused by two drivers reproducing the same frequency bands.) All MTM speakers, whether horizontal or vertical, are subject to this acoustic effect, but when aligned on the horizontal plane the effect is "across" the listening field rather than "up and down" through the field and is more likely to occur at the "ear height" of the listener. The impact of this can be distortion and reduced SPL in the critical vocal frequency bands, and is one reason why many home theater setups suffer from poorly understood vocals.


Using a center channel speaker is critical to proper HT performance, and using one aligned on the vertical axis generally yields the best results.

Using three "voice matched" speakers actor the front of an HT is critical to seamless sound location in relation to the action on screen, and using three identical loudspeakers yields the best results.

Do you have an evidence to support this ? It seems highly suspect that this is simply opinion.

This is far from opinion, it is basic acoustics. I do not have the time to give this forum a class in acoustics or home theater design, but I recommend you use your Google and do some research for yourself. Start with "wall to ceiling bass traps" and then do "loudspeaker lobing."

[novisnick]

Aug 24, 2018 9:19:41 GMT -5 DYohn said:

All six surfaces in a room effect sound similarly, depending on the dispersion patterns of the drivers. Indeed, the wall to ceiling corners are the most overlooked in listening room design and can create standing waves in the same ways as any other corner. Bass traps in this area can yield better results than in the traditional wall-interface corners in some rooms.

The issue that is caused by horizontal MTM arrangements of traditional center channel speakers is called lobing (cancellation caused by two drivers reproducing the same frequency bands.) All MTM speakers, whether horizontal or vertical, are subject to this acoustic effect, but when aligned on the horizontal plane the effect is "across" the listening field rather than "up and down" through the field and is more likely to occur at the "ear height" of the listener. The impact of this can be distortion and reduced SPL in the critical vocal frequency bands, and is one reason why many home theater setups suffer from poorly understood vocals.


Using a center channel speaker is critical to proper HT performance, and using one aligned on the vertical axis generally yields the best results.

Using three "voice matched" speakers actor the front of an HT is critical to seamless sound location in relation to the action on screen, and using three identical loudspeakers yields the best results.

You’ve made a much better argument and explanation for why this occurs on the horizontal plain. Perhaps thats why Ive always spent so much time setting up my always large and matched center channel. I haven’t heard of lobingin my searches believe it or not. 
Ive also found that placing my center just below screen and angled above the ears has given me a much better off axis result.  Thanks so much for taking your time with this discussion. If I ever have a setup where I can employ such an arrangement I’ll give it a try but as for my current HT I’m thrilled with the audio quality in both HT and Two channel.

[pedrocols]

Aug 24, 2018 10:11:45 GMT -5 emofrmcgy said:

Aug 24, 2018 9:19:41 GMT -5 DYohn said:

All six surfaces in a room effect sound similarly, depending on the dispersion patterns of the drivers. Indeed, the wall to ceiling corners are the most overlooked in listening room design and can create standing waves in the same ways as any other corner. Bass traps in this area can yield better results than in the traditional wall-interface corners in some rooms.

The issue that is caused by horizontal MTM arrangements of traditional center channel speakers is called lobing (cancellation caused by two drivers reproducing the same frequency bands.) All MTM speakers, whether horizontal or vertical, are subject to this acoustic effect, but when aligned on the horizontal plane the effect is "across" the listening field rather than "up and down" through the field and is more likely to occur at the "ear height" of the listener. The impact of this can be distortion and reduced SPL in the critical vocal frequency bands, and is one reason why many home theater setups suffer from poorly understood vocals.


Using a center channel speaker is critical to proper HT performance, and using one aligned on the vertical axis generally yields the best results.

Using three "voice matched" speakers actor the front of an HT is critical to seamless sound location in relation to the action on screen, and using three identical loudspeakers yields the best results.

Do you have an evidence to support this ? It seems highly suspect that this is simply opinion.

I bet you won't find a MTM center channel speaker or mismatched speakers at the movie theater. People at home and HT sales people have a big imagination.

[DYohn]

Aug 24, 2018 10:52:40 GMT -5 novisnick said:

as for my current HT I’m thrilled with the audio quality in both HT and Two channel.

And that's really all that matters, yes?

[emofrmcgy]

Aug 24, 2018 11:07:07 GMT -5 pedrocols said:

Aug 24, 2018 10:11:45 GMT -5 emofrmcgy said:

Do you have an evidence to support this ? It seems highly suspect that this is simply opinion.

I bet you won't find a MTM center channel speaker or mismatched speakers at the movie theater. People at home and HT sales people have a big imagination.

I bet you’re 100% correct.

[monkumonku]

Aug 24, 2018 11:10:56 GMT -5 DYohn said:

Aug 24, 2018 10:52:40 GMT -5 novisnick said:

as for my current HT I’m thrilled with the audio quality in both HT and Two channel.

And that's really all that matters, yes?

Not with "true" audiophiles!!!

[novisnick]

Aug 24, 2018 11:07:07 GMT -5 pedrocols said:

Aug 24, 2018 10:11:45 GMT -5 emofrmcgy said:

Do you have an evidence to support this ? It seems highly suspect that this is simply opinion.

I bet you won't find a MTM center channel speaker or mismatched speakers at the movie theater. People at home and HT sales people have a big imagination.

People that employ a HT system have so many compromises to make that it takes a genius to pull off a great sounding theater.

PERHAPS just MAYBE, budget comes to mind! LOL How many HT’s are 75’ X 35’ with 27’ ( or whatever the perfect dimensions are) ceilings and a minimum budget of what? 8 million US dollars? 

Come on now,,,,,ha,,,,ha,,,,, work with me! 😋

[KeithL]

Good explanation.

I should also point out that many true center-channel speakers, even though they may appear to be a standard M-T-M arrangement, really are not.

Even if the two midrange drivers are the same, it is not uncommon to apply frequency shaping to one of the drivers, so they're NOT actually reproducing the same exact frequency range.

When done properly, this can minimize or eliminate horizontal lobing at the crossover frequency.

(And, if it's done properly, you won't notice any left-right asymmetry...)

Aug 24, 2018 10:52:40 GMT -5 novisnick said:

Aug 24, 2018 9:19:41 GMT -5 DYohn said:

All six surfaces in a room effect sound similarly, depending on the dispersion patterns of the drivers. Indeed, the wall to ceiling corners are the most overlooked in listening room design and can create standing waves in the same ways as any other corner. Bass traps in this area can yield better results than in the traditional wall-interface corners in some rooms.

The issue that is caused by horizontal MTM arrangements of traditional center channel speakers is called lobing (cancellation caused by two drivers reproducing the same frequency bands.) All MTM speakers, whether horizontal or vertical, are subject to this acoustic effect, but when aligned on the horizontal plane the effect is "across" the listening field rather than "up and down" through the field and is more likely to occur at the "ear height" of the listener. The impact of this can be distortion and reduced SPL in the critical vocal frequency bands, and is one reason why many home theater setups suffer from poorly understood vocals.


Using a center channel speaker is critical to proper HT performance, and using one aligned on the vertical axis generally yields the best results.

Using three "voice matched" speakers actor the front of an HT is critical to seamless sound location in relation to the action on screen, and using three identical loudspeakers yields the best results.

You’ve made a much better argument and explanation for why this occurs on the horizontal plain. Perhaps thats why Ive always spent so much time setting up my always large and matched center channel. I haven’t heard of lobingin my searches believe it or not. 
Ive also found that placing my center just below screen and angled above the ears has given me a much better off axis result.  Thanks so much for taking your time with this discussion. If I ever have a setup where I can employ such an arrangement I’ll give it a try but as for my current HT I’m thrilled with the audio quality in both HT and Two channel.

[DYohn]

Aug 24, 2018 11:29:04 GMT -5 monkumonku said:

Aug 24, 2018 11:10:56 GMT -5 DYohn said:

And that's really all that matters, yes?

Not with "true" audiophiles!!!

You misspelled that. It's "Audiophooles".

[novisnick]

Aug 24, 2018 11:51:05 GMT -5 KeithL said:

Good explanation.

I should also point out that many true center-channel speakers, even though they may appear to be a standard M-T-M arrangement, really are not.

Even if the two midrange drivers are the same, it is not uncommon to apply frequency shaping to one of the drivers, so they're NOT actually reproducing the same exact frequency range.

When done properly, this can minimize or eliminate horizontal lobing at the crossover frequency.

(And, if it's done properly, you won't notice any left-right asymmetry...)

Aug 24, 2018 10:52:40 GMT -5 novisnick said:

You’ve made a much better argument and explanation for why this occurs on the horizontal plain. Perhaps thats why Ive always spent so much time setting up my always large and matched center channel. I haven’t heard of lobingin my searches believe it or not. 
Ive also found that placing my center just below screen and angled above the ears has given me a much better off axis result.  Thanks so much for taking your time with this discussion. If I ever have a setup where I can employ such an arrangement I’ll give it a try but as for my current HT I’m thrilled with the audio quality in both HT and Two channel.

Thank you @keithl I just knew there had to be just a little more brain power put into the design of a more complex center.
You make perfect sense and any engineer would try to fix an obvious problem before production. 👍🎶😁

[novisnick]

This is an older photo but the HT speaker placement is the same.
Plenty of Emotiva blue!

[pknaz]

Its also worth nothing, that center channel speakers, like the C-2 and the one in novisnick's image above, where the "midrange" speaker is below the tweeter and only the woofers are in an MTM configuration, won't experience the same horizontal lobbing issues.

[DYohn]

Aug 24, 2018 12:18:22 GMT -5 pknaz said:

Its also worth nothing, that center channel speakers, like the C-2 and the one in novisnick's image above, where the "midrange" speaker is below the tweeter and only the woofers are in an MTM configuration, won't experience the same horizontal lobbing issues.

Actually they will, just in the FR bands served by the drivers.