Surround music - rear channel issue

[RickH]

I posted this in the music forum and the thread disappeared into the pages without a reply at all! My intention wasn't to be negative on surround music - just a curiosity posting. So, here's an encore presentation of the original question:

I was thinking about surround sound in general terms after reading the article someone posted where the engineer spoke of the mix being such that it's like Crosby, Stills & Nash (or whoever the band was) all around you. It seems like there's a slight technical problem with the concept of matching surround speakers in that the back of your head is facing the rear speakers, your ears are getting the front & center channels direct on, so isn't this an audio anomally that whatever's mixed in the rear is going to be somewhat lesser in clarity & volume than the front channels since your ears are not getting their sound directly? Or, is this compensated for by the surround mix? Just curious. I'm getting ready to hook up my surround system later this week and will hear 5.1 for the first time, other than the lousy store displays, so I'll find out for myself but I thought it to be an interesting question.

Any thoughts, anyone?

[Dave D]

Well, if someone's standing behing you and talking, you still hear them pretty well, right? Your ears are pretty amazingly designed (thanks to the aliens and their know how!:D )
There may be some difference in clarity and frequency perception.....but take it from me, who spent 3 hours listening to DVD-A's/Sacd's last night......you hear the rears just fine!

[Gary Freed]

Hi Rick,

With Multi-Channel recordings, much depends on how the tracks were mixed.

When you go to a concert, typically speakers are set up on either side
front of stage, but there are also speakers set up in other locations as well, so that you windup with a surround effect.

Regardless of what salespeople might tell you there is a benefit to matching rear and front speakers though, It is called timbre matching.

For optimum speaker placement you should evaluate the room size as well as the seating area relative to the speakers. Experiment with different
configurations including speaker height above the ground especially if you are using bookshelf type speakers.

Pull the back of the speakers away from walls if possible.

Many recording engineers are mixing the rear speakers for ambience or filler. This method of mixing is more effective and recreates
a realistic soundstage.

All the best,

Gary:)

[GoldenBoy]

Originally posted by Gary Freed
Hi Rick,

With Multi-Channel recordings, much depends on how the tracks were mixed.

When you go to a concert, typically speakers are set up on either side
front of stage, but there are also speakers set up in other locations as well, so that you windup with a surround effect.

Regardless of what salespeople might tell you there is a benefit to matching rear and front speakers though, It is called timbre matching.

For optimum speaker placement you should evaluate the room size as well as the seating area relative to the speakers. Experiment with different
configurations including speaker height above the ground especially if you are using bookshelf type speakers.

Pull the back of the speakers away from walls if possible.

All true.

Originally posted by Gary Freed

Many recording engineers are mixing the rear speakers for ambience or filler. This method of mixing is more effective and recreates
a realistic soundstage.

All the best,

Gary:)

'more effective', is a very subjective statement. Personally, I feel that all styles of multichannel mixes can be 'effective', depending on the style of music. The 'ambiance' method, however, is very effective in recreating a more realistic soundstage and at capturing and placing you in the performance space. This method is particularly useful for Classical and some Jazz recordings.

[RickH]

Originally posted by wags
I have 5 channels in a semi-circle in front of my listening position, and 2 beside my listening position as surrounds. I have an A/B switch on my Adcom for the rears and "2nd" set of fronts.

This allows me to use the rears, or rears and extra fronts, for ambiance or audience effects on live recordings and DVDs.

If I'm listening to a discrete 5 channel mix, such as Beck Sea Change, I prefer to use the 5 channels in front of me and have the rears off. I get the benefits of the discrete mix and the enormous soundstage of the multi-channel mix without the distraction or unnatural sound I sometimes perceive with "surround" studio recordings. Allow me to emphasize that it is only my taste and perception regarding the rears being off and having 5 channels in front of me on Sea Change. I am envious (not critical) of those that are comfortable with instruments coming from beside or behind them because they don't have to buy an extra set of speakers like my weird *** had to do.


Steely's Dan's live DVD was not enjoyable for me before I had 7 speakers because I had horns and backing vocals coming from beside me when I was watching the musicians in front of me. It drove me nuts. Now, I just switch off the rears and get the vocals from the 5 channels up front. Awesome soundstage, very discrete, very natural.


Very interesting set-up & approach. Thanks for the input.

[levi]

a lot of audio/home theater magazines recommend putting your surround speakers on either side of where you sit.

http://www.liquidtheater.com/editorials/91

[therockman]

Of course, IMHO I feel that the largest factor in the whole surround sound debate is a little thing called psycho-acoustics. The human ear has evolved into a miraculous instrument that is capable of perceiving sounds in a 360 degree arc around the individual, but it is up to our brains to interpret and make sense of the aural information that the ear perceives. This mental processing of aural information is the point where every little spatio-temporal nuance is factored into the individual's ability to "discern" sounds and gain enjoyment from said aural experience. Like the famous philosopher once said, "What ever gets you through the night, it's alright, it's alright." Me, I personally love the whole surround sound experience with a fairly normal set-up. Front stage made-up of right/left and center, and rears way up high directly behind me. This is different that what dolby labs recommends for home theatre, but I set up my system exclusively for musical playback.

[GoldenBoy]

Originally posted by therockman
Of course, IMHO I feel that the largest factor in the whole surround sound debate is a little thing called psycho-acoustics. The human ear has evolved into a miraculous instrument that is capable of perceiving sounds in a 360 degree arc around the individual, but it is up to our brains to interpret and make sense of the aural information that the ear perceives. This mental processing of aural information is the point where every little spatio-temporal nuance is factored into the individual's ability to "discern" sounds and gain enjoyment from said aural experience. Like the famous philosopher once said, "What ever gets you through the night, it's alright, it's alright." Me, I personally love the whole surround sound experience with a fairly normal set-up. Front stage made-up of right/left and center, and rears way up high directly behind me. This is different that what dolby labs recommends for home theatre, but I set up my system exclusively for musical playback.

I prefer the ITU suggested setup for music playback, with only a slight variation on the suggested angle on the surrounds. I bring them just a tad closer to being directly at the sides than the ITU suggests.

[seriousfun]

Of course, the ITU standard is the place to start when placing home surround speakers. It is, with minor variations, the standard that most surround mixing starts with. Other, more creative implementations...well, it's a free country.

As to the original post, yes it is absolutely necessary to have the same timbre speakers in the rear and front. If you don't, you won't be starting from the same point the engineer probably started from, and you have to at least give the engineer that respect. Using some non-standard speaker setup IMO will not let you hear and enjoy the wide variety of treatments that different engineers use to deliver a surround music experience.

Our ears hear a sound differently if it is coming from behind us than they do if it is coming from the front. the shape of the ear, and the shape of our headscombine to affect our perceptions. Our ear/brain mechanism's millenia of evolution have programmed us to perceive sounds coming from behind as non-essential until they require essential processing; we don't track and analyze all jungle sounds around us until we need to instictually jump to the right front to escape the tiger springing on us from right rear.

An engineer isn't conciously analyzing what he or she is doing to sounds placed in the rear, compared to sounds placed in the front, but like every other decision, placement will affect eq, delay, level, etc.

[therockman]

I wholeheatedly agree with seriousfun regarding the nature of surround sound speaker matching. Although I recently set up my surround sound SACD system on a real tight budget, I went with the same brand speakers all the way around, with 12" 3 way speakers in the right left front, and 8" 3 way speakers in the rear. It is a quaint set-up, but the importance of tmbre matching can not be over emphasized.

[seriousfun]

Originally posted by therockman
I wholeheatedly agree with seriousfun regarding the nature of surround sound speaker matching. Although I recently set up my surround sound SACD system on a real tight budget, I went with the same brand speakers all the way around, with 12" 3 way speakers in the right left front, and 8" 3 way speakers in the rear. It is a quaint set-up, but the importance of tmbre matching can not be over emphasized.

Yes, and proper Bass Management can be your best friend here, negating the low-end response difference between the front and rear speakers.

[quadjoe]

Good Points, one and all! For a detailed read on surround sound have a look at this web site:

http://www.wendycarlos.com/gosurround.html

Wendy Carlos has been in the surround/quad arena for decades, and has some very clear thoughts on speaker placement etc. I highly recommend this site for interesting reading on this and a variety of subjects. Most of all, I hope you enjoy listening in surround sound as much as I do.


:thumbsup:

[therockman]

Thanks alot quadjoe, that was a great link with lots of great information. I myself love music in the surround and I am hoping for more titles on SACD to bring this joy to everybody.