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Speakers

Updated 06-May-2002 09:12:38 AM

There's more about subwoofers in the Beyond-the-Book topic Adjusting Your HT System.

Here's an article with more information about bi-wiring and bi-amping. And, to make them even clearer, here are some diagrams.

The book doesn't go into the three main types of surround speakers, direct, dipole, and bipole, so here's an explanation:

  • Direct (monopole) speakers have the speaker cones facing out into the room. They're the most common type of speaker.
  • Bipole speakers have at least two cones, one facing the room, and one facing backwards, so half the sound is direct, and half reflects off the wall.
  • Dipole speakers come in two forms: (1) Similar physically to bipoles, but with the speakers out-of-phase, so when the front cone is moving out, the rear cone is moving in, and (2) with both speakers almost in front, but pointed 90° off from each other, so if the speaker is mounted on the wall, the speakers are aimed along the wall.

(Some speakers don't actually have cones—they're flat—but the idea is the same.)

The chief difference between direct speakers on the one hand, and bipole/dipole on the other hand, is the the former gives a precise location for the sounds it emits, but the latter two diffuse the sound. Whether the sound should be directional or diffuse is a matter of opinion, but the usual recommendation for HT (from THX, for example) is that it should be diffuse. On the other hand, some people think direct is better for multichannel music from DVD-Audio or SACD.

If you want a diffuse sound and the speakers are going to go on the wall, your only choice is dipoles in a 90° arrangement, as there's no room for a speaker to fire rearward. An example would be the B&W DS6. (For information on the DS6, click here for the B&W site and search for "DS6".)

For more details and some nice pictures, see the article Mono/Di/Bi -Polar Disorder or Order, You Decide!

 

 

©2001, 2002 Marc J. Rochkind. All rights reserved. Send comments about this site to site@htexplained.com.