filtering and tweeter fs - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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
Thread Tools Search this Thread
Old 26th October 2007, 10:18 PM   #1
diyAudio Member
Join Date: Nov 2005
Location: alsace
Default filtering and tweeter fs

Hi guys,

At the begining of a new filter design process, besides all other considerations as distortions, directivity, x-max and on, do you have a general goal about the resulting level at tweeter resonance? For example: -10 or -15dbs at fs.
  Reply With Quote
Old 27th October 2007, 09:25 AM   #2
bjorno is offline bjorno  Sweden
diyAudio Member
Join Date: Mar 2005
Location: Jacobsmountain
Send a message via MSN to bjorno
As you rule out X-max thus what’s level dependent on the excursion only power consideration remains.

I try to keep the tweeter not to heat up to more than sin RMS half level i.e. - 3 dB of max RMS power at peaks, that is about 0.707 Vmax RMS.

From that level (power) the average music power level is often lower than 10 dB down keeping the tweeter most of the time cool.

The voltage level mentioned is also the maximum RMS sin voltage that I would apply at fs where the impedance could be of any value depending on tweeter type (Ferro fluid cooled or not), or i.e. when filter, notch filter is used or not (that would further decrease the level at fs).

I don’t have a rule for a general ‘dB down’ at fs as the applications could vary considerably with the tweeter type/brand and what I find is a suitable filter to use.

Through out the years I’ve used tweeter fs levels ranging between 0 to –24 dB down and the levels always set depending on the resulting achieved overall sound quality, thus sometimes restricting maximum available SPL.

But generally as long as you keep the voltage level below 0 dB = V max RMS at fs and at an octave below >=12 dB down, valid for most tweeters, the excursion would be constant from fs and below or slightly falling and x-max should occur at or above fs for most tweeters where advertised max tweeter power should be valid.

Watch out for the specifications, max power can be expressed as a function of an advised lowest frequency and recommended minimum filter slope to use.

  Reply With Quote
Old 27th October 2007, 03:35 PM   #3
diyAudio Member
Join Date: Nov 2005
Location: alsace
Thanks bjorno for your reply.

I projected to use my Focal Utopia be (fs 1500Hz) 3rd order cutoff frequency = 2500Hz. Result: fs is -17dbs / 87db maxi at 8500Hz (95db at 8500Hz without filter) and -40db at 750Hz. Thus largely enough protection!
  Reply With Quote


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
filtering before LM386? newsci Chip Amps 9 1st March 2014 11:24 AM
Mains Filtering audiofanaat Power Supplies 1 2nd February 2009 11:41 PM
On active filtering Dr_EM Solid State 22 7th June 2007 12:47 PM
CS4398 filtering? leadbelly Digital Source 3 1st January 2007 10:10 PM
PS EMI filtering xyrium Parts 4 2nd November 2005 06:20 AM

New To Site? Need Help?

All times are GMT. The time now is 09:52 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2