RE: Interesting observations

Posted by josh358 (P) on September 10, 2012 at 15:07:14

In Reply to: Interesting observations posted by Emsquare on September 10, 2012 at 14:11:34:

One of the most intriguing things I've read is that when you put a woofer near the listening position, the room aberrations are minimum phase. This is remarkably news since it means that you should be able to use equalization to eliminate completely not just amplitude aberrations but modal ringing from the sweet spot. Which, I think, for most of us, is enough. So you should be able to save money on woofers and get away with a smaller box and less disturbance to the neighbors, while completely eliminating room modes. Where do I sign up? It's in the bottom three paragraphs of the world's best dipole woofer page here:

http://www.musicanddesign.com/Dipole_modesA.html

I'm thinking I may give this a whirl with my sub before I sell it (I got it for the MMG's, it's too small to help out the Tympanis).

Otherwise, so many problems -- 10% harmonic distortion, thermal compression, reflections from within the enclosure emerging from the front, cone breakup, group delay, eigenmodes, woofer enclosure and building structure resonances, ringing from underdamped alignments, dipole cancellation, Allison effect proximity cancellation, etc., etc.

I'd like to hear a dipole woofer made with decent drivers like the GR Research, the Linkwitz, or Davey's subs (not sure what drivers he used) because I have no idea how they compare to the Tympani woofers that are my personal choice for best midbass ever, but, really, not the most practical things if you want to keep your marriage.

Two of the more interesting developments I've seen are the SBA and DBA, since below the spatial Nyquist frequency they can completely eliminate room modes in a rectangular room. Not terribly intrusive, either, you can build the woofer arrays into the walls (or ceiling). But kind of elaborate and expensive, and it's limited to lower frequencies (unless you want to use a zillion drivers and listen in mono).

I don't think most people have caught on to the fact that you can make a passive single bass array with a pair of Maggies. Harry Pearson, whose ear never ceases to amaze, hit upon it empirically, with his rule of thirds. I hit upon it with my 1-D's without really knowing what I was doing -- I figured that you'd get some cancellation of rear wall reflections if you were the same distance from the rear wall as the speakers were from the front, since the polarity-reversed reflection from the front wall would be delayed by the same time as the positive-polarity reflection from the rear, and when I tried it it worked. But in those days I didn't understand that the room surface reflections were creating a plane wave, it wasn't until I read about the DBA that I came to understand why it was so effective.

But why bother with any of that if you can get away with the box-near-the-chair technique? If it works as well as the calculations suggest, and you can make a really high quality enclosed dynamic sub (a bit questionable, I'm really not sure), it could put bass trap manufacturers out of business.

This post is made possible by the generous support of people like you and our sponsors:

Follow Ups Full Thread

Topic - Holy moley, I actually won one? - Emsquare 09:44:05 09/08/12 (33)

RE: that never happens - hemholtz 18:44:53 09/08/12 (30)

RE: that never happens - dazzdax 09:27:56 04/09/13 (0)

RE: that never happens - Emsquare 05:23:01 09/09/12 (4)

RE: that never happens - hemholtz 12:25:19 09/09/12 (3)

RE: that never happens - josh358 18:03:24 09/10/12 (2)

RE: that never happens - hemholtz 19:18:04 09/10/12 (1)

RE: that never happens - josh358 10:08:08 09/11/12 (0)

RE: that never happens - triamp 03:34:45 09/09/12 (23)

RE: that never happens - hemholtz 13:15:20 09/09/12 (0)

RE: that never happens - josh358 06:54:41 09/09/12 (21)

RE: that never happens - triamp 23:37:44 09/09/12 (20)

RE: that never happens - hemholtz 12:34:18 09/10/12 (3)

RE: that never happens - triamp 16:12:48 09/10/12 (1)

RE: that never happens - hemholtz 17:41:24 09/10/12 (0)

RE: that never happens - Emsquare 13:48:20 09/10/12 (0)

RE: that never happens - josh358 06:34:39 09/10/12 (15)

Interesting observations - Emsquare 14:11:34 09/10/12 (12)

RE: Interesting observations - josh358 15:07:14 09/10/12 (11)

RE: Interesting observations - Emsquare 16:38:15 09/11/12 (6)

RE: Interesting observations - josh358 10:15:05 09/13/12 (5)

RE: Interesting observations - Emsquare 17:13:23 09/14/12 (4)

RE: Interesting observations - josh358 18:00:10 09/14/12 (3)

RE: Interesting observations - Emsquare 09:10:57 09/15/12 (2)

RE: Interesting observations - josh358 09:42:21 09/15/12 (1)

RE: Interesting observations - mmlrot1 12:24:25 04/09/13 (0)

RE: Interesting observations - Emsquare 17:49:03 09/10/12 (3)

RE: Interesting observations - hemholtz 17:57:47 09/10/12 (2)

RE: Interesting observations - Emsquare 16:09:29 09/11/12 (1)

RE: Interesting observations - hemholtz 16:59:38 09/11/12 (0)

RE: that never happens - Norman M 09:05:37 09/10/12 (1)

RE: that never happens - josh358 09:37:49 09/10/12 (0)

RE: Holy moley, I actually won one? - JBen 10:36:24 09/08/12 (1)

RE: Holy moley, I actually won one? - Emsquare 15:24:56 09/08/12 (0)

Follow Ups

RE: Interesting observations - josh358 15:07:14 09/10/12 (11)

RE: Interesting observations - Emsquare 16:38:15 09/11/12 (6)

RE: Interesting observations - josh358 10:15:05 09/13/12 (5)

RE: Interesting observations - Emsquare 17:13:23 09/14/12 (4)

RE: Interesting observations - josh358 18:00:10 09/14/12 (3)

RE: Interesting observations - Emsquare 09:10:57 09/15/12 (2)

RE: Interesting observations - josh358 09:42:21 09/15/12 (1)

RE: Interesting observations - mmlrot1 12:24:25 04/09/13 (0)

RE: Interesting observations - Emsquare 17:49:03 09/10/12 (3)

RE: Interesting observations - hemholtz 17:57:47 09/10/12 (2)

RE: Interesting observations - Emsquare 16:09:29 09/11/12 (1)

RE: Interesting observations - hemholtz 16:59:38 09/11/12 (0)

RE: Interesting observations

Post a Message!