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

Swap Meet Sell your stuff here, who knows, some other fanatic might be interested!

JBL 5234,  Professional Series Frequency Dividing Network - AND and interesting story
JBL 5234,  Professional Series Frequency Dividing Network - AND and interesting story
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 7th December 2011, 08:21 PM   #1
bobcul is offline bobcul  United States
diyAudio Member
Join Date: Nov 2011
Default JBL 5234, Professional Series Frequency Dividing Network - AND and interesting story

For Sale -- JBL, Model 5234, Professional Series Frequency Dividing Network (two units)

These are two channel crossover networks that are set at 400Hz and 1.6kHz crossover points, 18dB/octave. This creates a pair (left - right) of three way audio channels bass to 400 Hz, Mid 400 to 1600 Hz, and high above 1600 Hz.
Removed from service into storage, excellent condition, NOT TESTED
If you are interested contact - Bobcul@nospam.locul.com to discuss the particulars

Now for the interesting part. These were used in a dance club sound system with Paired JBL bass folded horns with two 15' Cetec drivers each, two Cetec 10" K series instrument speakers in two splayed sealed direct radiating mid-range enclosures, and a Pair of Heil Air Motion Transformer (AMT) stacks for everything above 1600 Hz. Each stack was four units high. With the crossover frequency raised from 1kHz to 1.6kHz, and power divided into the four units, they stood up to heavy loading. Previously we had worked with ESS on the Heil AMTís through about five iterations of failure and redesign of the diaphragms and finally came up with the 25 Line, High Power Teflon, Bridal Vail Reinforced design.

Open field SPL mapping of various stack combinations of the AMTís showed a relatively narrow vertical high frequency beam pattern as expected with a broad horizontal pattern. The horizontal patterns were relatively constant with frequency. I still have the test data and plenty of photographs.

The AMT stacks were given about 10 degrees of mechanical down tilt. From their mounting point atop the base and mid range cabinets, they were above ear level on the dance floor. This produced a slightly attenuated level close in to the speakers, off to the side of the main vertical sound lobe, and increasing level at increasing distance as one moved away from the speakers and into the high frequency main beam.

Future work was anticipated, but never done, which would have been to frequency shape the power to the speakers. For example applying full spectrum from 1.6kHz cross over to high frequency cutoff to only one element, half bandwidth from low to about 8kHZ to a second element, and 1/4 BW from crossover to about 4kHz to all four elements. The goal would be to achieve a more uniform or better controlled vertical pattern. We still needed a narrow beam but perhaps the side lobes could be cut down.

This all analogous to RF and optics ;-)

Bob Culver, P.E.
Broadcast Consultant
Attached Images
File Type: jpg P1060248 - CROP - SMALL.jpg (173.2 KB, 76 views)
  Reply With Quote


JBL 5234,  Professional Series Frequency Dividing Network - AND and interesting storyHide 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
JBL Amplifier story Bassamps Tubes / Valves 10 25th November 2015 11:05 AM
JBL 5234A vs 5234 Frequency dividing networks vannozzi Solid State 4 4th January 2013 09:04 PM
RCA professional series receiver chipper Everything Else 0 12th October 2010 09:28 PM
Accuphase DF-45 Digital Frequency Dividing Network oceanic30 Multi-Way 6 4th September 2006 07:05 AM
for sale pair of 4pi professional series speakers bqc Swap Meet 0 20th May 2005 03:20 AM

New To Site? Need Help?

All times are GMT. The time now is 09:25 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio