Imaging Q...Sitting Location vs. Sound

[Thai]

Hey all,

This may be a stupid Q...forgive my ignorance in this topic. In my theater setup, my Vantages are slightly toe-in. If i sit in the middle (same axis as center channel), then the sound is great...coming from both Vantages (and CC). However, if i sit at the end of my couch to one side, i don't hear much from the opposite side Vantage speaker...for example, if i sit on the left side, then i mostly hear just the left Vantage and CC.

Is this normal?? I am new at this whole theater thing, but i thought that the whole point to 5.1/6.1/7.1 surround sound is that no matter where you sit within the listening area, you should hear equal sound from front...that is, "there is no bad seat in the house."

If this is not normal, then i guess that i need to toe-in more the Vantages, right??

Thanks in advance.

 

[Thai]

One more Q...does imaging improve with breaking-in the speaker or is it just the lower end of the frequency that gets better??

 

[MiTT]

Thai, that's a bit of a loaded question, but I'll give you my $.02 worth.

First let's make sure we agree on the definition of imaging. I don't run my system as a home theater set up, so I may be biased. I don't think you're going to have a great "image" in most theater applications by the very nature of the media being presented. You may occasionally get some stable images with a sense of dialog coming from the center channel, and possibly acoustic cues from your other speakers indicating a real sense of the acoustic space where in any given movie scene may take place. But the whole point of a 5.1, 7.1 9.1 type setup is to involve you in an ever changing acoustic reality that corresponds to the visual one occuring on the screen.

From a 2 channel perspective, imaging is the ability to identify a sense of real instruments and voices appearing in a real space, the ability to localize those instuments and voices, and to differentiate them from one another locally, tonally and temporally. That is to say, you know that violins are to the left of the viollas, which are in turn to the left of the cellos and basses are to the right, and all of the strings are in front of the woodwinds and horns with percussion spread out in the back. On a really good system you'll be able to localize individual rows and even instruments. Most of the time though the musicians are staying in one place. Occasionally, with rock or jazz recordings you'll hear individuals moving around the soundstage, but things like drums usually stay anchored in one spot. The point is that this "image" of instruments spread out in front of you mimics what occured at the original recording and on a good system it can be very convincing.

Imaging is one of the things that our Martin Logans do extreemly well. My system has the resolution to do exactly as I have mentioned above when the source material contains the appropriate level of information in the recording. Unfortunately, the manner in which our speakers present this recoverd information - acting as dipolar line sources - means that the very best imaging can only be percieved in the infamous "sweet spot" that unfortunately really only comes into focus for one or possibly two people seated in the appropriate spot in front of the speakers.

This isn't uncommon to any speaker that has great imaging characteristics. For the most part if you want that wonderful characteristic it's going to be a tradeoff for those who are listening off axis. The only real exception I have heard to this is the rather amazing mbl 101's.

Hope this helps...

 

[Thai]

Thanks Tim...a very good explanation...Ok, i feel better now!!

 

[IWalker]

I've never heard speakers that I felt imaged outside of the sweet spot. Generally, when I feel that, I realize it's because they don't image very well in the sweet spot...so the change when I move around isn't nearly as pronounced. I haven't heard very many GREAT speakers, though. Certainly not the MBLs, which I would certainly love to hear, even though they are WAY out of my price range!

I don't know how you would be able to accurately reproduce the soundfield as you move around, considering the nature of the recording setups used, and the inherent physical limitations of speakers (an orchestra stage might be 100 ft wide, and you're trying to get that sort of line source projection from two small speakers) Getting the imaging right just for one spot seems pretty incredible to me. In listening to an orchestra, where you sit has a direct and significant impact on the sound. If you're closer to the left side of the stage, the violins will be more prominent, if you're sitting to the right, the cellos and bass will be more prominent. As you shift left and right, there is a very gradual change, because each instrument is a point source that together works as a line source from the stage. With speakers, it's two point sources (even if they're vertical line arrays) trying to simulate this. As such, I'd think that as you move, the change in tonal balance becomes much more pronounced than it would with the real thing, due to the radiating pattern differences between the two. I don't see how this could really ever be addressed without having an actual wall of speakers, and a wall of microphones to record from!

This just comes from my limited understanding, however...so feel free to correct me if I made a false assumption or two.

 

[Pcar928fan]

The only real exception I have heard to this is the rather amazing mbl 101's.

Hope this helps...

That will be my next speaker purchase! SOME DAY! In Piano black there is NOTHING more striking than a 101!

 

[MiTT]

I've never heard speakers that I felt imaged outside of the sweet spot. Generally, when I feel that, I realize it's because they don't image very well in the sweet spot...so the change when I move around isn't nearly as pronounced. I haven't heard very many GREAT speakers, though. Certainly not the MBLs, which I would certainly love to hear, even though they are WAY out of my price range!

I don't know how you would be able to accurately reproduce the soundfield as you move around, considering the nature of the recording setups used, and the inherent physical limitations of speakers (an orchestra stage might be 100 ft wide, and you're trying to get that sort of line source projection from two small speakers) Getting the imaging right just for one spot seems pretty incredible to me. In listening to an orchestra, where you sit has a direct and significant impact on the sound. If you're closer to the left side of the stage, the violins will be more prominent, if you're sitting to the right, the cellos and bass will be more prominent. As you shift left and right, there is a very gradual change, because each instrument is a point source that together works as a line source from the stage. With speakers, it's two point sources (even if they're vertical line arrays) trying to simulate this. As such, I'd think that as you move, the change in tonal balance becomes much more pronounced than it would with the real thing, due to the radiating pattern differences between the two. I don't see how this could really ever be addressed without having an actual wall of speakers, and a wall of microphones to record from!

This just comes from my limited understanding, however...so feel free to correct me if I made a false assumption or two.

IWalker, yes, this is essentially the same thing I was attempting to say in my typical long-winded style.

 

[MiTT]

That will be my next speaker purchase! SOME DAY! In Piano black there is NOTHING more striking than a 101!

They are indeed amazing transducers, they would be on my short list of cost no object aquisitions...

 

[mitrolyat]

Very good discussions about radiation pattern relative to listening position.

I think achieving uniform dispersion throughout the theater environment is required to approximate sound sources delivered in av presentations. This means to me that point and line sources may not be thoroughly appropriate. Every situation is different, but what seems to make sense to me in a 5.1 are wide or omni dispersion mains with a balanced, uncolored center, bipole/dipole/omni surrounds (hidden source). Obviously, putting such a configuration together may involve mismatches and multiple compromises.

The panels disperse sound in an inherent pattern. As with all speaker designs, their particular pattern delivers the type of sound the buyer wants and needs. The ML sweetspot can be wondrous in 2ch or multich. I think much is determined by the room configuration and system expectations.

I am sure there is much to disagree with here, but it's just my 2¢. Good luck.

 

[Thai]

I come from car audio. For example, you have the driver and passenger in the front seat...each one is close to a pair of speakers. Obviously, there is an inherent imaging problem in a car. The way to get around this is to aim the tweeter to the opposite person (ex: driver's tweeter points to passenger's ear, while passenger's tweet points to driver's). It's not a perfect solution but it works well enough. Of course, nowadays, new cars have a center channel to even out the imaging issue even more. And the high tech cars (Lexus Mark Levinson) uses frequency and timing delays to further widen the sweet spot in a poor acoustic environment.

What is the problem with turning my Vantages more "toe-in"??

 

[mitrolyat]

Thai, very interesting car audio information.

I didn't experiment much with toe-in degree in a mch setup. My mains were positioned for 2ch/single listener. Just curious, are your left and right boundaries common material and are your Vantages relatively symmetrical?

By the way, you have a very nice system!

 

[Thai]

Thai, very interesting car audio information.

I didn't experiment much with toe-in degree in a mch setup. My mains were positioned for 2ch/single listener. Just curious, are your left and right boundaries common material and are your Vantages relatively symmetrical?

By the way, you have a very nice system!

Yup, my left and right walls are the same...same texture, same paint. The Vantages symmetical...and i am very anal about these things!

My room is longitudinal...16 x 11. I have U-shaped couch...and the length of the couch is about 9 feet across. And when you sit on the side of the couch, you hear mostly just the CC and that side Vantage. This would not bother me much if it was just vocals because my CC would be the main speaker. However, during a movie, you have soundtracks and this become slightly less than perfect experience when i hear music mostly out of just one front tower (if i sit on the side of dead center), not the whole front stage (music from two towers and CC).

Thanks for the compliment on my system...just need to get an amp one of these days.

 

[Thai]

Over the next day or so, I am going to try and toe-in my Vantages more towards the center. Any ill effects if i do this in terms of frequency augmentation or canceling out??

Thanks again for answering these basic questions from a HT newbie.:cheers:

 

[Charliemike]

I'm going to take advantage of this thread to talk about the same things that Thai talked about.

I FINALLY (*does a dance*) have my MLs in my condo. I haven't hooked them up yet (not til this weekend) but I have a question ...

I have SL3s ... I am sitting about 9' from where the center channel would be if I had one I have the MLs about 8' feet apart (I can't really go farther apart due to space limitations.

I haven't considered the width of the sound field per speaker from 9' away (don't know how to find out that calculation) but my thinking was that the further I spread them out (within reason) the less off-balance (like Thai seems to be hearing) the sound field will be.

Because I have a reclining couch, I tend to sit at one side or another. In hindsight, perhaps a reclining 2-seat loveseat would have been a better choice but I bought the couch long before the SL3s

I'm sure I'm going to get some "turn those puppies on and play around with them based on what you hear" but I'm wondering if I'm barking up the right tree.

I'm trying to avoid what Thai is hearing.

Thanks all!

 

[MiTT]

Over the next day or so, I am going to try and toe-in my Vantages more towards the center. Any ill effects if i do this in terms of frequency augmentation or canceling out??

Thanks again for answering these basic questions from a HT newbie.:cheers:

No, just experiment with their position until it sounds right to you. I would suggest that you utilize the Jim Powers "Flashlight" method as a starting point, and that you fine tune listening to 2 channel music that you know very well until you find that everything snaps into place. If you get the 2 channel part set up right it will work well for HT.

 

[Jeff Zaret]

I agree with Tim on this which does give you a good place to start. I would also take measurements from each side to the back wall as you "angle" the speakers this way you will have a reference point and not pull your hair out.


Jeff

 

[Thai]

I'm trying to avoid what Thai is hearing.

Thanks all!

I am sure that YOU won't have a problem because the imaging around the center position is good (or either side of center). My problem is at the extremes of my room, where you are closer to one side than the other.

With my current position, i actually like 5-channel stereo better than 2-channel. There seems to be more spaciousness (aka enveloping sound) in the 5-channel mode than pure stereo mode. Again, i guess that you guys are right...i just need to play around with it more. I will definitely toe-in my Vantages more to see the effects of it.

Oh yeah, i did do the flashlight test on the current positioning.

Next week is free for me...so you bet my anal ass will be in my theater room 24/7!!

 

[Thai]

Ok...i couldn't wait till next week...i spent 3 hours yesterday and 1 hr tonight to adjust the speaker distances from wall and center channel...down to the last centimeters!

I did toe-in my speakers more...so that, if i were to use the flashlight test, my light would hit about 2/3 of the inner panel (instead of the recommended 1/3). My ELS panel is 33" from front wall and 24" from side wall. My main sitting area is about 1.5 feet more than the distance between my two Vantages. My center channel is slightly less than 1 foot behind the Vantages (aka less than 1 foot farther from sitting area than Vantages).

Result: sound is much better when i am sitting at the edges of the couch on either side. In pure stereo mode, my Vantages do sound better with them farther away front wall. Sound stage/imaging is perfect now...for now.

 

[Charliemike]

Ok...i couldn't wait till next week...i spent 3 hours yesterday and 1 hr tonight to adjust the speaker distances from wall and center channel...down to the last centimeters!

I did toe-in my speakers more...so that, if i were to use the flashlight test, my light would hit about 2/3 of the inner panel (instead of the recommended 1/3). My ELS panel is 33" from front wall and 24" from side wall. My main sitting area is about 1.5 feet more than the distance between my two Vantages. My center channel is slightly less than 1 foot behind the Vantages (aka less than 1 foot farther from sitting area than Vantages).

Result: sound is much better when i am sitting at the edges of the couch on either side. In pure stereo mode, my Vantages do sound better with them farther away front wall. Sound stage/imaging is perfect now...for now.

This post is worthless without pics!

 

[Joey_V]

Ok...i couldn't wait till next week...i spent 3 hours yesterday and 1 hr tonight to adjust the speaker distances from wall and center channel...down to the last centimeters!

I did toe-in my speakers more...so that, if i were to use the flashlight test, my light would hit about 2/3 of the inner panel (instead of the recommended 1/3). My ELS panel is 33" from front wall and 24" from side wall. My main sitting area is about 1.5 feet more than the distance between my two Vantages. My center channel is slightly less than 1 foot behind the Vantages (aka less than 1 foot farther from sitting area than Vantages).

Result: sound is much better when i am sitting at the edges of the couch on either side. In pure stereo mode, my Vantages do sound better with them farther away front wall. Sound stage/imaging is perfect now...for now.

What did I say? Yup, the new MLs sound better if toed in aggressively...

Joey :cheers: