Jump to content
The Classic Speaker Pages Discussion Forums
Sign in to follow this  
Aadams

Boston CR series CR65 5 inch cone driver

Recommended Posts

I just noticed this today.  Boston CR65 nominal 5 inch cones have a dust cap that is not like any dust cap on any speaker I have ever had.  Notice the photo below:  The bullet shaped dust cover remains stationary while a sleeve on the cone moves over it.  Is this a common construction these days.  The cone driver crossover is 4200hz, about 1khz higher than the point where it would become beamy using the 13560 rule.  Does anyone know the purpose of this form of design?  Just curious.

image.thumb.png.73dda2acbce7da9b31662ae05f4d5187.png

Share this post


Link to post
Share on other sites

My Dayton RS 225 -4 8" woofer looks like this too. Usually it is called a phase plug. Not sure it is essential for good sound. 

Share this post


Link to post
Share on other sites
1 hour ago, ligs said:

Usually it is called a phase plug. Not sure it is essential for good sound. 

Thanks.  I have been reading about phase plugs.  Apparently it permits even higher crossover points before beaming becomes a problem.  I couldn't find much on it but the stationary hard surfaced plug seems to scatter frequencies with wavelengths less than the width of the cone that would otherwise beam out from the center if there were a fixed dust cap.  I don't really know what I am talking about but that is what I picked up from several hits regarding cone mid woofers with phase plugs.

Adams 

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...