Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

New waveguided tweeter from SB Acoustics
New waveguided tweeter from SB Acoustics
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 16th November 2019, 09:12 PM   #11
kd1yt is offline kd1yt  United States
diyAudio Member
 
Join Date: Dec 2018
Location: Vermont, USA
Has anyone heard any forecasts of the availability date or price of the new SB waveguide tweeter?


Thanks
  Reply With Quote
Old 16th November 2019, 09:33 PM   #12
El patator is offline El patator  France
diyAudio Member
 
Join Date: Sep 2014
Location: France
Quote:
Originally Posted by kd1yt View Post
Has anyone heard any forecasts of the availability date or price of the new SB waveguide tweeter?


Thanks
They are avalaible
I paid 60 euros each
I should get my hands on them next week.
  Reply With Quote
Old 16th November 2019, 10:22 PM   #13
aperiodic is offline aperiodic  Serbia
diyAudio Member
 
Join Date: Jun 2018
Location: Serbia
Dynaudio D28 and D21 had a kind of a waveguide, introduced in 1977 and 1978
  Reply With Quote
Old 16th November 2019, 10:51 PM   #14
mayhem13 is offline mayhem13  United States
diyAudio Member
 
Join Date: Sep 2008
Quote:
Originally Posted by Patrick Bateman View Post
That dip in the high frequency response is why I use 3/4" domes on my waveguides. I haven't found a way to reliably avoid it. I've tried phase plugs, to no avail.

Ring radiators avoid it, but ring radiators have less displacement than domes. (Because a ring has less area than a circle.)
It would seem with power handling limitations, the 3/4 dome is the ideal waveguide candidate.
  Reply With Quote
Old 16th November 2019, 10:53 PM   #15
ILikeFoodz is offline ILikeFoodz  United States
diyAudio Member
 
Join Date: Jun 2014
Does anyone know what specifically causes the dip at high frequency and why a 3/4" solves it? I assume the 3/4" pushes it above 20kHz, but I'm curious where it comes from.

Edit: Looks like it's at the frequency that corresponds to a 1 inch wavelength. Still not sure why it shows in waveguides and not non-waveguide tweeters though.

Last edited by ILikeFoodz; 16th November 2019 at 10:56 PM.
  Reply With Quote
Old 17th November 2019, 01:11 AM   #16
kd1yt is offline kd1yt  United States
diyAudio Member
 
Join Date: Dec 2018
Location: Vermont, USA
Quote:
Originally Posted by El patator View Post
They are avalaible
I paid 60 euros each
I should get my hands on them next week.

Interesting, and thank you. That (assuming an exchange without more markup to USD) favorably less than the Wavecor waveguide tweeters and this seems like it would be of at least equal, perhaps moderately higher quality. I wonder when they'll show up at retail in the US or at Solen in Canada?
  Reply With Quote
Old 21st November 2019, 08:28 AM   #17
davewantsmoore is offline davewantsmoore  Australia
diyAudio Member
 
Join Date: Sep 2009
Location: Australia
Quote:
Originally Posted by ILikeFoodz View Post
Does anyone know what specifically causes the dip at high frequency and why a 3/4" solves it? I assume the 3/4" pushes it above 20kHz, but I'm curious where it comes from
Yes, the shape of the dome (ie. it is dome not flat)
  Reply With Quote
Old 21st November 2019, 09:08 AM   #18
Patrick Bateman is offline Patrick Bateman  United States
diyAudio Member
 
Patrick Bateman's Avatar
 
Join Date: Oct 2006
Location: San Diego
Quote:
Originally Posted by ILikeFoodz View Post
Does anyone know what specifically causes the dip at high frequency and why a 3/4" solves it? I assume the 3/4" pushes it above 20kHz, but I'm curious where it comes from.
1) 13,500Hz is one inch long

2) when two sources are one half wavelength out of phase, they cancel each other out. (Destructive interference)

3) One half of a 13,500Hz wavelength is 1/2" long

So, it's simply geometry: as your radiator gets larger and larger, you start to get peaks and dips that are caused by it's geometry. For instance, the TIP of a one inch tweeter is nearly one half of a wavelength out of phase with the EDGE of a one inch tweeter, above 10khz.

There's a few ways to fix this:

1) use a flat diaphragm

2) use a diaphragm that's "flattish." For instance, if you look at JBL and Infinity domes, you'll notice they're flatter than Dynaudio domes. This is because JBL uses waveguides.

3) Use a smaller diaphragm

4) Use a ring

5) Some combination of the above

Most of JBL's studio speakers have switched from a one inch throat to a 0.625" throat, for the reasons that I describe, and they're driven by a ring radiator.


Quote:
Originally Posted by ILikeFoodz View Post
Edit: Looks like it's at the frequency that corresponds to a 1 inch wavelength. Still not sure why it shows in waveguides and not non-waveguide tweeters though.
Click the image to open in full size.

With no waveguide, the radiation is spherical

When you put a waveguide in front of a source, the walls of the waveguide bend the wave if the wave is smaller than the diameter of the waveguide.

For instance, picture a waveguide that's two inches wide. 6,750Hz is two inches wide. This means that *everything* above 6,750Hz is going to get bent by the walls of the waveguide.

If that makes sense, than you can see why there's a lot of reasons to bring those walls in closer, by using a smaller tweeter.
  Reply With Quote
Old 21st November 2019, 05:49 PM   #19
ILikeFoodz is offline ILikeFoodz  United States
diyAudio Member
 
Join Date: Jun 2014
That makes a lot more sense. Thanks for the detailed answer!
  Reply With Quote

Reply


New waveguided tweeter from SB AcousticsHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
FS: SB Acoustics Beryllium tweeter SB29BNC-C000-4 raelman Swap Meet 5 16th July 2019 05:53 PM
SB Acoustics Ceramic Dome Tweeter SBS26CDC dtaylo3 Multi-Way 14 12th April 2019 09:48 PM
SB Acoustics SB21RDC-C000-4 tweeter 454Casull Multi-Way 2 13th April 2018 09:38 PM
wtb: microstatic micro-acoustics tweeter array Altecboy Swap Meet 1 9th November 2010 04:04 PM
Looking for a nice horn/waveguided tweeter David Gatti Multi-Way 1 25th April 2007 03:20 AM


New To Site? Need Help?

All times are GMT. The time now is 05:31 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki