"Proac 2.5 clone" or "Elsinore project" - Page 2 - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

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 26th May 2011, 05:51 AM   #11
diyAudio Member
 
Joe Rasmussen's Avatar
 
Join Date: Jan 2003
Location: Sydney, Australia
Send a message via MSN to Joe Rasmussen
A little belatedly I thought I'd add my tuppence worth.

There is always an inherent and potential problem when doing a high-end DIY speaker design: That somebody beyond the control of the original designer may not get the design exactly right. Guess who may have to unfairly wear criticism? I know of at least one instance where the DIY'er dispensed with the passive crossover and went for an active crossover. Other than providing the most basic of advice, it is impossible to predict how something like that will work out. Not surprisingly, the Tweeter was turfed out and replaced with a "better" unit. If only things were that simple.

What follows below will help explain why the Tweeter didn't work out.

Also: Even the slightest chance of somebody getting it wrong in the crossover can have a dramatic effect on the performance. Now I will bare myself, even I have made a mistake, but realising it very quickly. I would of course quickly know, where others might not. But crossover mistakes are easy to make.

The issue re the HDS cum Scan-Speak Discovery Tweeter: Distortion in Tweeters is a major issue, particularly in dome Tweeters.

We do not have the benefit of LR4 crossover here - so we need to come up with a working solution.

The solution in getting low distortion out of the HDS Tweeter in a 1st order crossover, is how you control it's output below 2KHz and the source impedance the Tweeter sees looking backwards. In the Elsinores it sees a sub 1 Ohm at circa 650 Hertz (Fs), keeping the dome output down to less than 10% compared to many other situations. This is done by a carefully tuned null-filter and it dramatically lowers distortion. The Q of the null is critical as it has significant effect on the output in the 1-2KHz octave.

(BTW, the same trick also works well with XT25, but the HDS is better.)

The response is 1st Order for at least one octave below 3Khz and then goes into a 5th-6th Order fall which bottoms out below 1 Ohm as discussed above. See graph.

Need I also mention the phase characteristics? These are also well controlled.

Thanks for Joel - I appreciate him starting this thread.

Cheers, Joe R.
Attached Images
File Type: gif Image8.gif (35.2 KB, 271 views)
__________________
The "Elsinore Project" DIY Speaker System
Custom Analogue Audio - we also support and promote non-profit DIY
  Reply With Quote

Reply


Hide 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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
The "Elsinore Project" Thread Joe Rasmussen Multi-Way 1826 Today 02:52 AM
What Does Fostex "Rated Input" and "Music Power" mark02131 Full Range 5 13th October 2012 05:18 AM
What makes an amplifier "bright", "warm", or "neutral"? JohnS Solid State 51 13th December 2009 06:42 PM
Some final pics of "Stacks" revisited and "Askew" with stand Andy G Multi-Way 2 3rd February 2005 06:07 AM
Anyone used Scan-Speak's "Flow Resistors" or "Aperiodic Vents"? Ignite Multi-Way 3 18th November 2001 08:42 AM


New To Site? Need Help?

All times are GMT. The time now is 03:29 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2