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

North Creek & the W18E cone resonances
North Creek & the W18E cone resonances
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
Thread Tools Search this Thread
Old 13th June 2006, 01:00 PM   #1
Virtalahde is offline Virtalahde  Finland
diyAudio Member
Join Date: Jan 2006
Location: Kuhmoinen, Finland
Default North Creek & the W18E cone resonances

Obviously, while reading this stuff, you've got to keep in mind that people are trying to sell you something. But I wonder what this means, because I couldn't find any explanation of the final idea in taming the cone break-ups.

Eventually it came to me that the problem with the W18ís upper midrange is a two edged sword. The mechanical break up of the cone is a high Q mechanical resonance. The "low pass network plus trap" approach creates a second high Q resonance. The problem, then, is that there are two high Q resonances in the electrical/mechanical/acoustic system right in the middle of the range where the ear (at least mine) is most sensitive. My goal, then, became to design a low pass network with the target acoustic response, but without using this type of filter. Finally, some progress was being made.
The whole story is here:

The idea I get from this one would be the equivalent of having an active cross-over where there's a low pass filter combined with a fixed-Q, bell curved dip to attenuate the signal enough to not excite the mechanical resonance of the driver. Which, in theory would be the equivalent of a similar L-C series filter, but apparently North Creek Music thinks it's not.

So.. What did they do? Is there any truth behind this? Does the series filter "ring" and store energy with the cone break-up? Did they simply use two different low passes (one a tad lower, one a little higher) to mimic the FRQ response of a bell-curved dip (not that it would)?

Why so many questions?
  Reply With Quote
Old 13th June 2006, 04:05 PM   #2
sreten is offline sreten  United Kingdom
Join Date: Nov 2003
Location: Brighton UK
Hi, You should ignore such technowaffle. I do. /sreten.
  Reply With Quote
Old 13th June 2006, 11:11 PM   #3
Curmudgeon is offline Curmudgeon  United States
diyAudio Member
Join Date: Nov 2005
I tend to suspect that the two opposing resonant circuits analogy is an over-simplification. From the description of the breakup, a simple trap would not be able to fully compensate for the breakup.

One possibility would be an elliptical filter for the lowpass. The Josephaudio speaker company uses very steep crossover slopes,
JosephAudio Metal Cone Waterfall to also deal successfully with the same issue. The Waterfall (Cumulative Spectral Decay curve) they show indicates why a simple LC trap is inadequate.

I personally prefer a completely different approach; an Audio Technology midrange which has the same qualities of transparency and timbre, and is as easy to design with as such drivers can be. (Although to some extent this shifts the money from the xo to the driver.)

The Northcreek caveats about associated equipment and xo parts quality are very much to the point.
  Reply With Quote


North Creek & the W18E cone resonancesHide 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
What North Creek talks about? andy2 Multi-Way 5 23rd November 2005 10:34 PM
WTB: 6 North Creek d25's bhg41088 Swap Meet 0 29th December 2004 08:37 AM
north creek d28 pxr5 Multi-Way 4 1st November 2004 05:15 PM
North Creek Danse Multi-Way 0 7th October 2004 10:39 PM
North Creek Thunder sduford Multi-Way 0 7th March 2004 02:35 PM

New To Site? Need Help?

All times are GMT. The time now is 12:29 PM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio