Speaker's Fr variation with signal level - Page 4 - diyAudio
Go Back   Home > Forums > Loudspeakers > Full Range
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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 5th August 2005, 04:38 PM   #31
gpapag is offline gpapag  Greece
diyAudio Moderator
gpapag's Avatar
Join Date: Nov 2002
Location: Athens-Greece
All the above measurements (Vas, Q and past Fs measurements) show results that are approaching the published specs when the excitation signal is at a higher level (>400mV RMS). The lower test signals (especially below 100mV RMS) show results far away from the published data and at the same time quite sensitive to small signal variations. This, together with the fact that listening levels are produced by a signal of not less than 300mV RMS on these speakers, makes me choose the higher signal level characteristics, these of around 500mV RMS.

  Reply With Quote
Old 5th August 2005, 05:15 PM   #32
soongsc is offline soongsc  Taiwan
diyAudio Member
soongsc's Avatar
Join Date: Mar 2005
Location: Taiwan
Originally posted by gpapag
Hi all
I took the time to do some more manual measurements to check for any change occurring to Q and Vas of the JX92S relative to excitation signal.
Results below:
Vas increases across the full span of applied signal.
How do you determine VAS? This is not directly measured.
Hear the real thing!
  Reply With Quote
Old 5th August 2005, 08:43 PM   #33
gpapag is offline gpapag  Greece
diyAudio Moderator
gpapag's Avatar
Join Date: Nov 2002
Location: Athens-Greece
Quote from soongsc:"How do you determine VAS? This is not directly measured."

Vas is determined using the closed box method. An unstuffed closed box with volume Vb<Vas/2 is used:
1. Measure Free air resonance freq. of driver (fs)
2. Measure In-Box resonance freq. of driver (fct). Both measurements with exactly the same signal amplitude
3. Calculate Vas=1.15[(fct/fs)^2 -1]Vb

Method is referenced in Vance Dickason “Loudspeaker Cookbook” fourth Edition pages 131-132 and David Weems “Great Sound Stereo Speaker Manual” first Edition page 208

Vas data as well as Q data and Fr data at the attachment. (Color at the columns represent: Blue=Set data, Yellow=Measured data, Green=Calculated data).

Attached Files
File Type: zip p7r.zip (11.1 KB, 11 views)
  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
Speaker level to line level converters qguy Subwoofers 2 9th December 2007 03:58 PM
speaker level input vs line level question crippledchicken Subwoofers 4 17th July 2007 03:36 AM
Level of the input signal Progg70 Analog Line Level 2 27th August 2005 04:51 PM
How do I turn an high current signal into a line level signal?? sardonx Tubes / Valves 8 27th August 2005 11:16 AM
how to bring down line level signal to preamplifier level deji Solid State 15 15th April 2004 04:13 PM

New To Site? Need Help?

All times are GMT. The time now is 03:06 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