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Direct or Reflect ... What's your flavor

Was thinking about this from another thread. When we think of a basic speaker we usually think of monopoles. That is, speakers with a single baffle or plane from which sound emanates out of to the room, but as long as I can remember there are examples at all price ranges of speakers designed specifically to reflect, or whose basic construction forced rear or side reflections. Among the "forced to reflect" categories:

  • Electro static speakers (Martin Logan, Sanders, etc.)
  • Open Baffle / di-pole
Then we have ambient reflectors, which I include:
  • Bose 901 and smaller direct/reflecting models
  • Snell with their rear tweets
  • Wilson 
  • Probably numerous others
Let be clear though, NONE of these ambient reflectors are accurate. None of these latter elements can be called a way of credibly and accurately increasing the transmission of information from the recording to our ears. To my mind these are all in the land of bass shakers. They add some pizzazz and excitement, and perhaps an illusionary venue.

So, still, for your music and tastes, who has gone with di-poles or ambient reflecting speakers and never looked back?
erik_squires
bdp24's avatar
bdp24
9,788 posts
 

Duke made at least one great point (there is more than one, but I’m focusing on the one): the off-axis response of a loudspeaker is ideally the same as it’s on-axis response. When accomplished, the total in-room power response (direct sound, reflected sound) is uniform, irrespective of frequency. Danny Richie discusses this important design consideration (as well as add-on tweeters and other related issues) in one of his Tech Talk Tuesday videos.

One other point needing to be made is that monopole loudspeakers (forward-firing enclosure designs) are monopoles at only certain frequencies---where the individual drivers begin "beaming" (a function of wavelength vs. driver diameter). Below the beaming frequency, the sound coming out the front of the speaker wraps around the enclosure and propagates towards the back wall, just as does the sound coming out of the rear of a dipole.

I know one Maggie owners who uses heavy absorption behind his MGIIIa’s, due to room constraints. He accepts the lack of a rear diffused sound field, preferring in some ways the more "direct" sound of a forward-only planar. Each to his own.

erik_squires OP
16,049 posts
 
One other point needing to be made is that monopole loudspeakers (forward-firing enclosure designs) are monopoles at only certain frequencies



We're now conflating dispersion with speaker topology, which I was trying to get at. Besides, even when the driver is significantly narrower than the frequency so as to cause wide dispersion, the dipole still behaves very differently.

Best,

E
bdp24's avatar
bdp24
9,788 posts
 

Of course, Erik. The point I was making is that even direct radiators create front wall (behind the loudspeakers) reflections. Dipoles/planars do at all frequencies, direct radiators at bass frequencies up into the midrange (depending on driver diameter).

And that is just 1st wave sound. That front wall also reflects sound reaching it from the rear wall, side walls, and the ceiling.

tomic601's avatar
tomic601
12,911 posts
 
Yes a rear firing tweeter is 100% distortion 
tomic601's avatar
tomic601
12,911 posts
 
Part of fixing crappy recordings involves picking distortion your ear brain likes
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