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

Planars & Exotics ESL's, planars, and alternative technologies

Inconsistent Ribbon Measurements
Inconsistent Ribbon Measurements
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 11th June 2019, 10:58 PM   #1
ericimage2 is offline ericimage2  United States
diyAudio Member
Join Date: Jun 2014
Default Inconsistent Ribbon Measurements

Hi, I have a technical question if anyone can answer, I was measuring the DCR of my ribbon tweeters of my GT3R GT Audio works speakers and I am confused, If I use my $30 SouthWire multi-meter i get a resistance of 3.7 ohms but if I use my fancy $400 BK LCR meter using DCR setting I get 19.2 ohms but if I measure the resistance (R) or Impedance (Z) at 1 Khz I get 3.675 ohms and 3.854 ohms respectively.

Also w hen I measure the DCR with the BK LCR Meter the ribbon tweeter moves a lot but with no sound, and when measuring R or Z I can hear the expected 1 Khz tone. In the other hand with the SouthWire MM It does not move or make any noise when I measure the Ohms.

Why does it moves so much with the BK measuring DCR and why is the DCR value so high on the BK?

BTW I tested the BK and is calibrated!

Thanks a lot for the answers!
  Reply With Quote
Old 14th June 2019, 11:07 PM   #2
bolserst is offline bolserst  United States
diyAudio Member
bolserst's Avatar
Join Date: Jun 2005
Location: Fort Worth, Texas
What Model of B&K LCR Meter do you have?

Most of them do not measure true DC resistance. Instead, they take an AC impedance measurement(usually at ~100Hz) and calculate the resistive and reactive parts of the impedance at that frequency and display the resistive portion. You mentioning that you can see the ribbon moving makes me think this is the case and the AC excitation frequency is close to the resonance of the ribbon.

Some of the newer B&K meters also give the option to choose between modeling the impedance as two elements(resistive, reactive) in series or two elements in parallel. I know the B&K Models 878 and 879 default to the parallel model when resistance is selected which may be what is happening in your case. Switching to the series setting should get you a resistance reading much closer to the true DC .

For example, 4ohm in series with 200uF if measured with the parallel model would display 19.8ohm instead of 4 ohm.
Attached figure created with spreadsheet posted here:
ESL electronics 101 for the electronics challenged
Attached Images
File Type: png Zseries_vs_Zparallel.png (98.6 KB, 83 views)
  Reply With Quote


Inconsistent Ribbon MeasurementsHide 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
inconsistent impulse respons 2 computers charlie2 Multi-Way 5 21st January 2019 11:42 AM
LTSpice FFT simulation settings and inconsistent results. Mooly Software Tools 106 25th June 2013 02:14 AM
FS: Fountek NeoPro5i Ribbon Tweeter - Matched Pair With Measurements! opc Swap Meet 2 10th March 2013 12:14 AM
JX92 + Ribbon + VTL enclosure: measurements neil_kaye Full Range 6 21st May 2008 01:52 AM
Thorens TD 125MKII speed inconsistent? 600LPs Analogue Source 0 26th October 2007 06:32 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 © 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