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Indirect VS direct sound radiation for surrounds?

post #1 of 6
Thread Starter 
Anyone have an opinion about direct radiating surrounds vs indirect (angled drivers, dipole, bipole).

I would think that best system for believable surround would be ALL the speakers being the same. (All bookshelves for instance). When we were running old dolby pro logic the diffuse rear sound was needed but now with specific sound tracks recorded to each channel it would seem that indirect radiation would muddy the channel? Is this logic wrong? I would love to hear some opinions.
post #2 of 6


EVERYONE has an opinion on this topic, it has been discussed ad nauseum for years and in many threads on this forum. If you already have your own belief for best sound, why do you care what anyone else thinks?
post #3 of 6
Quote:
Originally Posted by SiXeVeN View Post

Anyone have an opinion about direct radiating surrounds vs indirect (angled drivers, dipole, bipole).

I would think that best system for believable surround would be ALL the speakers being the same. ...

Perhaps for music, but not for movies. All major releases are mixed on rather large dubbing stages, which are configured like commercial movie theaters. There are many surround speakers, and the best acoustic match to this for the home theater is using indirect radiation for surrounds.

Regards,
Terry
post #4 of 6
Thread Starter 
Interesting! So the back channels are supposed to blend? It would seem to make sense that a diffuse back area would present a more realistic sound envelope but at the same time I can imagine that a perfectly matched set of 4 speakers all with great imaging would create the same impression.

Is it more an issue of rooms being to corrupted to present good imaging with direct speakers? Or, are the channels in a movie sound track designed to be diffusely projected and trying to do it with direct projection leads to a loss of sound envelopment?

Sorry about the questions, but i'm trying to design a system where the listener feels enveloped in a sound stage and not just detecting sounds from front or back.

For instance, I have always been sensitive to the subtle differences in timbre that exist between a set of mains and their supposed matched center channel. When a movie scene pans accross the sound stage the small difference in SQ ruins the aural effect for me. It sounds less like something moving from left to right and more like the speakers turning on and off left to right (if that makes sense).

It seems there are two options. Indirect radiation of the Fronts AND Rears with a center channel to "anchor" the vocals. OR Direct sound in perfectly matched speakers so the sound fields blend into one another creating a 3D imaging effect.

Given what i'm trying to create... Which of those options seems to be the better option? Or is there another option??? Thanks all!
post #5 of 6
Quote:
Originally Posted by SiXeVeN View Post

Anyone have an opinion about direct radiating surrounds vs indirect (angled drivers, dipole, bipole).

I would think that best system for believable surround would be ALL the speakers being the same. (All bookshelves for instance). When we were running old dolby pro logic the diffuse rear sound was needed but now with specific sound tracks recorded to each channel it would seem that indirect radiation would muddy the channel? Is this logic wrong? I would love to hear some opinions.


For mixers where you are meant to be able to localize where the 'surround' sound is coming from, direct firing is recommended. E.g., many multichannel rock/pop music mixes.

For mixes where the surround sound is supposed to provide 'ambience' or envelopment rather that well-localized sounds, indirect firing is recommended.
E.g. many movies, multichannel classical and jazz mixes.

So it's really mix-dependent. The ideal all-purpose surround speakers would allow two configurations, switchable as needed.
post #6 of 6
Quote:
Originally Posted by krabapple View Post

The ideal all-purpose surround speakers would allow two configurations, switchable as needed.

Do any other speaker manufacturer's other than M&K (defunct, but trying to arise) with their SS-150thx's make surrounds that you can switch from:

Dipole
Tripole
Tripole with Attenuated Dipole Elements
Tripole with Adjustable Attenuated Direct Radiator
Tripole with Adjustable Attenuated DiPole Elements
Tripole with Maximum Output from All Drivers
Direct

These surrounds are super configurable, and I would think that other manufacturers would attempt to put out something similar, no?
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