Dedicated surrounds versus bookshelves for rear channels

[mcbr1]

I have heard some say that they prefer bookshelves for the rear channels instead of "proper" rear channel speakers. Why is this and what advantages does each option bring? Thanks.

[bobsticks]

I prefer floorstanders but that's just me. I listen to more multi-channel music than movies.

Smaller speakers (that's what I assume to mean "proper" surrounds) are easily mounted to wall or ceiling according to Dolby Guidelines ( http://www.dolby.com/uploadedFiles/z...sic_Mixing.pdf ) and should do the job for ambient and spacial cues. Some may prefer bookshelves or larger for varying degrees of greater presentation.

[Woochifer]

"dedicated" surround speakers typically refer to those models that use a dipolar or bipolar design that diffuses the sound in order to keep them from sounding localized. This is actually a remnant that dates back to the earlier Pro Logic era and the first set of THX specs.

Both of these programs were aimed at mimicking the theatrical speaker arrangement, with arrays of speakers along the wall, as much as possible by creating a placeless null sound at the point source. With the advent of discrete 5.1 soundtracks, this approach is no longer needed.

IMO, you're much better off using direct-firing speakers in the surround channels, and optimizing the sound by properly positioning the speakers (following Dolby's guidelines of pointing the surround speakers directly at one another and raising them above ear level). Because of how soundtracks are mixed, with some ambient cues still in the surround channels, you don't still don't want the speakers to act too much as a point source. OTOH, you also want the alignment to create the directional imaging cues that a 5.1 soundtrack (purposed for home theater use) will create.

Generally, you will want the surround speakers positioned higher than ear level, so bookshelf speakers give you the most flexibility for optimizing the alignment and height. Floorstanding speakers are best suited to large rooms and multichannel music -- a lot of movie soundtracks won't work optimally because of they might still use the original theatrical mixes that have a lot of ambient sounds mixed into the surrounds.

[Poultrygeist]

Since the signal content to the rear channels is much less than what is sent to the fronts it makes sense to use smaller ( = less expensive ) speakers there. While matching driver voicing is critical across the front channels it is less critical for the rears.

[Woochifer]

Since the signal content to the rear channels is much less than what is sent to the fronts it makes sense to use smaller ( = less expensive ) speakers there. While matching driver voicing is critical across the front channels it is less critical for the rears.

Gonna disagree with you on that, because the trend with movie soundtracks, especially those that are repurposed for home theaters, is to shift more signal content to the surround channels. What might have been true a decade ago is no longer the case.

Now, sound designers are getting more aggressive with mixing the sound elements between the front and surround channels at near equal levels. They also create side imaging cues by sharing and rebalancing sounds in the front and surround channels. Especially when music is involved, having timbre matching between the front and surround speakers has a huge impact on the surround effect and the quality of the imaging.

I used mismatched surround speakers for nearly two years before I purchased a pair of timbre matched speakers. The difference is very pronounced. While yes, you can get away with mismatched surrounds, it's definitely not something to recommend as a long-term solution.

[Poultrygeist]

The content on the Blu-ray discs I'm listening too is purely sound effect augmentation for the rear channels.

[pixelthis]

Since the signal content to the rear channels is much less than what is sent to the fronts it makes sense to use smaller ( = less expensive ) speakers there. While matching driver voicing is critical across the front channels it is less critical for the rears.

WHO TOLD YOU THAT?
In a HT situation as much as 90% goes to the center, the front left/right are surrounds just as much as the rears.
I have been using floorstanders for rears, out of necessity, but have found that they work
really well, adds a little bass ommmp to the back.

[mcbr1]

"dedicated" surround speakers typically refer to those models that use a dipolar or bipolar design that diffuses the sound in order to keep them from sounding localized. This is actually a remnant that dates back to the earlier Pro Logic era and the first set of THX specs.

Both of these programs were aimed at mimicking the theatrical speaker arrangement, with arrays of speakers along the wall, as much as possible by creating a placeless null sound at the point source. With the advent of discrete 5.1 soundtracks, this approach is no longer needed.

IMO, you're much better off using direct-firing speakers in the surround channels, and optimizing the sound by properly positioning the speakers (following Dolby's guidelines of pointing the surround speakers directly at one another and raising them above ear level). Because of how soundtracks are mixed, with some ambient cues still in the surround channels, you don't still don't want the speakers to act too much as a point source. OTOH, you also want the alignment to create the directional imaging cues that a 5.1 soundtrack (purposed for home theater use) will create.

Generally, you will want the surround speakers positioned higher than ear level, so bookshelf speakers give you the most flexibility for optimizing the alignment and height. Floorstanding speakers are best suited to large rooms and multichannel music -- a lot of movie soundtracks won't work optimally because of they might still use the original theatrical mixes that have a lot of ambient sounds mixed into the surrounds.

Does this hold true for all listening rooms? My listening area has a fireplace on one side and is open on the other, so my surrounds are mounted on the back wall just 2 feet behind the listening position and a bit outboard. Bookshelves would have to be placed on stands much lower and fire at each other from a spot very close to the rear wall and outboard. Which sounds like a better solution?

[Sir Terrence the Terrible]

Does this hold true for all listening rooms? My listening area has a fireplace on one side and is open on the other, so my surrounds are mounted on the back wall just 2 feet behind the listening position and a bit outboard. Bookshelves would have to be placed on stands much lower and fire at each other from a spot very close to the rear wall and outboard. Which sounds like a better solution?

It does not hold true for all listening rooms, and certainly not for yours. Wooch is speaking to more optimized spaces(four walls with equal symmetry). With folks turning everything from a bedroom to a living room into a "listening room", it would be hard to apply his advice universally.

[Woochifer]

The content on the Blu-ray discs I'm listening too is purely sound effect augmentation for the rear channels.

Without proper level matching, positioning, and voice matching, you won't hear how much of an impact the surround channels actually make.