Home High Efficiency Speaker Asylum

Need speakers that can rock with just one watt? You found da place.

[ Follow Ups ] Thread: [ Display  All  Email ] [ High Efficiency Speaker Asylum ]
[ Alert Moderator ]

Interesting question

Unless one has an infinite baffle it will have diffraction. And anything on or near the baffle that is not flat in the baffle (like other drivers) will also diffract the sound. Even objects not on the enclosure but on nearby walls can difract the sound. Don't think that it is just simply the baffle edges that we are talking about here. We (Lidia and I) have been learning that diffraction is a major issue for both imaging and sound quality despite the fact that it appears so benign in a frequency response curve. Hence, one of the limitations of "flat" frequency response being ideal - ala DEQX, etc. which DON'T correct for diffraction (at best at a single point, at worst, not at all).

Diffraction is always delayed in time relative to the direct signal. The ear masks well in frequency, but not so well in time. SO what may be benign and masked in frequency becomes quite audible with just a small amout of time delay - exactly like diffraction. It also turns out that this effect is absolute SPL dependent as well as frequency dependent. At freq < 1 kHz diffraction is not an issue. It becomes more of an significant with frequency, peaking at about 3-6 kHz. Diffractions in this range may not be audible at 80 dB SPL, but can be quite annoying at 100 dB SPL (these are linear values).

Back to the original question. We don't want ANY diffraction above 1 kHz, and if we do it should be delayed as little as possible. So the best choice is clearly to elliminate the diffraction above 1 kHz and then the baffle size is irrelavent. This can be done with a radius of sufficient size at ALL the edges and corners. I have found that a minimum of 2" is required, but the more the better. I use 2" in my enclosures, which makes assembling them in wood a big problem, hence the molding technique.

If you are not going to radius your edges then they should be as close to the source as possible. But remember that there is no way to get the edges so close that if they are not radiused they won't be an audible problem at some SPL level. And then there is the back edge of the cabinet ...

Personally I would only consider speaker that did not have any sharp edges anywhere near the front drivers - and that includes the rear edges, other drivers, COSMETICS!! The front baffle should be as smooth and boring as possible. It's kind of like Stealth aircraft. You have to consider everything and sometimes that makes things look ugly (ala F-118).

Hope that answers your question.

Earl Geddes

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

Follow Ups Full Thread
Follow Ups
You can not post to an archived thread.

[ Top Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2025, Audio Asylum, all rights reserved ]
[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]