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Discussion Starter #1
If one uses his/her system completely for movie with 5.1, 7.1,etc... Is toe in the left/right speakers necessary? Which movie clip would you guys suggest to experiment this? Are speakers in commercial theater toed in? Thanks.
 

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If one uses his/her system completely for movie with 5.1, 7.1,etc... Is toe in the left/right speakers necessary?
Depends on the speaker, specifically the high frequency dispersion angle, but in general, yes. Most speakers have a 30 degree full bandwidth dispersion angle (+/- 15 degrees from directly on axis). If you can cover all your HT seats with that and not toe in, then you don't have to. Won't usually happen, BTW, except for a few specifically designed for the purpose.
Which movie clip would you guys suggest to experiment this?
Anything with a sustained high end. No specific movie clip, but pink noise and REW would be a good choice.
Are speakers in commercial theater toed in? Thanks.
Most are, a few aren't. The good ones probably are though a theater speaker should, in theory, have controlled dispersion that covers all seats, usually with their -6dB point at 80 or 90 degrees (total, not +/-) A bit of toe-in on the L/R screen speakers will help get the high end to the seats on the opposite side of the theater while keeping the seats on the same side in balance. They also aim them vertically too.
 

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Nothing is necessary in speaker placement. It is a matter achieving the sound quality that appeals to you most. Only you can be the judge of what appeals to you the most.


Most people find that the toe in improves the sound by aiming the tweeters at their ears. That brings the full output of the tweeters to bear. There is always some audible loss off axis. You may prefer things another way. That's OK.
 

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I think it all depends on how you have your speakers placed and the distance between them and the listener.

I normally aim the fronts a foot to the left and right of the main listening position. To test that I have them aimed correctly, I listen to music or a movie at the main listening position. If the speakers are aimed correctly, then you should have a clear phantom center image of voices while still being able to distinguish different sounds from the left and right speakers. I then move a seat over and the center image should still be present, not as clear, but it should still sound as if the voices are coming from a point in the center while still being able to hear the sound effects from the left and right. If the image falls off right away when you move over then you have them toed in too far.

I pretty much do this over and over till the image falls off at the farthest point in the seating area. The general rule of making an equilateral triangle between the speakers and seating position works really well in being able to achieve what I do.
 

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Discussion Starter #5
I almost have a equilateral triangle with about 7.5' on each side. How do you hear that phantom center if there is a center speaker producing that center channel sound? Do you leave the center speaker off while testing this? Then what's the point of trying to create that phantom center when there is a center speaker doing just that already?
What should I be looking for on REW graph with pink noise while trying various toe in angles? I have 60x90 horn speakers. My sealed room is about 14W x 19L x 9H. All front three tweeter are at ears height. Thanks.
 

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I have found that toe-in is always neccessary to achieve the best possible imaging. Even though you have a center speaker to play stuff from the center you still want the stuff on either side of it to image as well as possible. Try 15-25 degree toe-in(this is usually so that you just can see the outside of the speaker cabinet from the sweetspot). But you have to play around with it. To test imaging put on a song in stereo. A song with a vocals placed dead center with some instruments to either side is a good test. If you have to strain yourself in any way to hear placement the imaging is off. If all instruments etc. are place dead center you probably toed in too much and if the center image is fuzzy you probably did too little.

How far away from the speakers are you sitting? A good ratio between distance between speaker tweeters and seating position is 1.18. So if you have speakers 3 meters apart you should sit 3 x 1.18 = 3.54 meters from the center point between the speakers.

Another advantage of toe in is that imaging is acutally better off axis. This is pretty logical if you think about it.
 

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Discussion Starter #7
^^ Thanks. My speakers are 7.5' apart and I am about 8.5' from them. I can see the point of having the vocal death center with stereo speaker pair. I am curious about the 5.1/7.1 movie mix where each channel is mixed discretely, so would we want sound from left is coming from left, right from right, center from center?
 

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^^ Thanks. My speakers are 7.5' apart and I am about 8.5' from them. I can see the point of having the vocal death center with stereo speaker pair.
If you don't already have a center, that's job one. More important than toe in, by a lot. At risk of repetition, 80% of the total sound in a film soundtrack is mixed to the center channel. If you don't use a center, that channel is spread evenly between L and R, but you will not get the right mix at all.
I am curious about the 5.1/7.1 movie mix where each channel is mixed discretely, so would we want sound from left is coming from left, right from right, center from center?
What other way is there?
 

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What other way is there?
The point of my question is why toe in the left and right trying to get image centered from them where there already is a center doing that. With discrete 5.1/7.1 movie mix, don't we want sound from left and right coming where they are instead of having center image from them by toeing in?
 

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^^ Thanks. My speakers are 7.5' apart and I am about 8.5' from them. I can see the point of having the vocal death center with stereo speaker pair. I am curious about the 5.1/7.1 movie mix where each channel is mixed discretely, so would we want sound from left is coming from left, right from right, center from center?

But I believe that there will still be sounds that image between L and R. Even if that never happens toe-in will still help the overall sound experience if you sit slightly off center. With no toe-in sitting slightly to the right or left will result in either the R or L speaker dominating in sound and distracting from the experience. The goal should be to never ever "hear" a speaker but to be in a bubble of sound. But most of the time the biggest problem is usually poorly placed surrounds where you end up having a speaker in you ear.
 

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Various recommendations are there to start from, like shown below:



and this one:


and the current guide from Dolby:
http://www.dolby.com/us/en/guide/surround-sound-speaker-setup/7-1-setup.html



Probably to do it scientifically having a polar plot of your speakers dispersion could guide you.
Why do it though is the point....to have better imaging, to have less side wall first reflection strength (giving better imaging), to have more consistent spl across multiple rows of seats....

I've adjusted my front row R/L toe in and truly noticed the difference.
Actually I've also adjsted my side surrounds recently for toe in / toe down to MLP


added this bracket just 2 months ago
 

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The point of my question is why toe in the left and right trying to get image centered from them where there already is a center doing that. With discrete 5.1/7.1 movie mix, don't we want sound from left and right coming where they are instead of having center image from them by toeing in?
Toe-in doesn't affect the position of the center phantom image, it affects the available seating area where the full high-end is present.
But I believe that there will still be sounds that image between L and R. Even if that never happens toe-in will still help the overall sound experience if you sit slightly off center. With no toe-in sitting slightly to the right or left will result in either the R or L speaker dominating in sound and distracting from the experience. The goal should be to never ever "hear" a speaker but to be in a bubble of sound.
Toe-in affects speaker dominance only at the high end, because with toe-in you cover the seating area with full bandwidth, without it, the coverage is left or right dominant depending on where you sit. But it's a high-end only problem, mid band speakers are pretty wide, like 90 degrees @ 1KHz vs 30 at 10KHz.
But most of the time the biggest problem is usually poorly placed surrounds where you end up having a speaker in you ear.
And Lo! The dipole surround speaker born of necessity.
 

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Probably to do it scientifically having a polar plot of your speakers dispersion could guide you.
If only we had polars. I once asked a rather prominent speaker manufacturer who sells on-line direct with an easy demo/return policy about polar plots of a couple of their speakers so I could design a room. I was told they had them, but didn't provide them. Huh? Why, because they show their speakers to be vacuum-enabled? That was my only possible conclusion. Nothing at all about off-axis response was available.

Say/think what you want about THX, the Ultra2 spec defines horizontal and vertical dispersion, it becomes a known instead of an unknown. Polars are not so necessary once you have that. But for every other speaker, you work blind or test for yourself, either audibly or with instrumentation.

Just another "secret spec".
 

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^^^or we invest $90 into a calibrated measurement mic, use REW, and have some fun jumping down the acoustical rabbit hole ... ;)
Correlate the subjective (our ears) to the objective (the data), and have fun with it all while our sig other rolls their eyes and says "oh well, it's a hobby thing"


edit - added the below
http://www.klipsch.com/Education/general-faq
Finally, we recommend, with Klipsch speakers, that the midrange/tweeter horn be "toed-in" toward the listener to create the best imaging.
 

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The point of my question is why toe in the left and right trying to get image centered from them where there already is a center doing that....
You asked about toe-in, so it makes sense folks responded with ways to adjust your speaker orientation for best imaging over the widest seating area. It's a set-up method.

A set-up methodology is not a listening recommendation. The idea is to place each speaker so it, individually, contributes in an optimal way to a multi-channel listening space. Listening for the phantom center image from stereo speakers across your listening area is one good criteria for adjusting L/R speakers. The multichannel result is then getting everything that the L/R speakers have to offer.

Put another way, if you did a sub crawl, where you put the sub where you sit, and find the best sub location by crawling around to find the best quality bass, you'd always reverse placement when you're done, so you sit where you want and the sub sits where it works best. Optimization tools and approaches are frequently non-sensical until you understand how they fit into the system, as a whole.

Have fun,
Frank
 

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How about toe-ing the rear/back surrounds? Does it make a huge difference?

Huge is subjective....I've not taken objective data but I do notice more even sound SPL seat to seat when doing simple test tones..
I've only toe in / toe down my side surrounds so far...


Via Mikes brain/thumb interface, LLAP
 

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How about toe-ing the rear/back surrounds? Does it make a huge difference?
For my surrounds, i have them directly to the sides of the listening position and toed in towards the rear wall at about a 30 degree angle, but keep in mind that I have acoustic panels on the rear wall, but I find this scenario to work best for me as it covers the whole seating area, while not sounding too direct to the listener sitting in a seat closest to the speaker.
 

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You also want to make sure you have your speaker delays (Distance) set properly. To check that everything is set properly, i playback a mono track and play it back in All Stereo mode from the receiver and everything should sound centered without hearing one speaker more than the other.
 
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