[TerryO]

  
    Just one person's opinion based on his experience.   

One more potential application: Some single drivers, Compact Hemps included, have rear firings ports. I wonder it the rear port might also benefit?

Here's another person's opinion: I wouldn't bother with the port on a rear vented speaker. The use of felt on a baffle is an old trick that has been around for a long time, in fact some speakerbuilders go so far as to use felt with a "faceted" (negative star shape) edge to partially cover the surround of the driver. This often means that the felt must be elevated with an additional layer of felt in order to avoid having the felt actually contacting the surround. It often helps with diffraction issues and can improve the overall presentation, but there's little or nothing to gain by surrounding the port with felt... if the speaker is correctly designed

Best Regards,
TerryO

[jimdgoulding]

Rich and Always-  I'm sending you a PM. 

[Alwayswantmore]

Rich and Always-  I'm sending you a PM. 

Jim, I got your PM and I responded. Thanks for answering my questions. Kent

[jimdgoulding]

JLM made an observation on page 1 about waveform behavior and single driver speakers and something has occurred to me.  I'm thinking that the correction is taking place lower in frequency than, say, on a two way speaker with a smaller baffle and that while a single driver is larger and deeper, it is not sufficiently acting as a waveguide and the longer wavelengths are interacting with the abundant baffle space speakers like Omegas and Carolinas have.  I've just delivered to a couple more AC members and maybe they can be encouraged to share their impressions after awhile.  Thanks.  Jim