Vibration/Loose Brace

Get the lowdown on the down low.
Post Reply
Message
Author
mj90210
Posts: 10
Joined: Fri Feb 03, 2017 2:12 pm
Location: Montana-USA

Vibration/Loose Brace

#1 Post by mj90210 » Fri Oct 20, 2017 11:38 pm

Hello to all,

I finished the build of 4-dual loaded T60's and I am more than pleased. Formal review to follow. One of the cabinets unfortunately has a noticeable vibration/rattle/ from maybe 50hz and up. All the braces in the mouth seem secure and stable. I put a glass bottle on top of a functioning cabinet and the bottle does not move, put the bottle on top the cabinet with vibration and the bottle jumps and moves around. Is there anyway to identify what brace may be loose? If it is brace 2/8, does the force/movement on panel 8 indicate it is loose on the 2-panel or 8-panel? To find the location of the braces I envision plunge cutting perpendicular to the brace line at the front of the cab and rear to determine the CL of the brace, screwing, sealing, painting...assuming the brace is loose on panel 8.... If it is on 2 that might be a little more difficult.. Long winded but looking for solutions or ideas...

Also, so much respect Mr. Fitzmaurice for designs and respect for all that build any of these cabinets. All the effort was worth it once I heard them sing...Unbelievable. I have been to indoor venues with 40+ PK CX800's, and I am more than pleased with the sound quality and output.
Thank You All for Your Time!!...Really!

Built:
4xDual-30” Tuba 60’s
1x20” THT
TrT 10" Driver-10" Wide

jimbo7
Posts: 496
Joined: Fri Dec 28, 2012 10:45 am
Location: St. Louis

Re: Vibration/Loose Brace

#2 Post by jimbo7 » Sat Oct 21, 2017 1:13 pm

Lay it on different sides and stand on it to see where it stops rattling. If you find it then drive some screws in the braces and or panels. Good luck. I had to demolish one because I couldn't find the rattle.
BFM builds:
XF212
T24 BP102 24"
2x SLA's 6-5" mids, 9-gt-302's
2x AT 14" MCM 55-2421
TrT 5" MCM 55-2421
AT 18" JBL GTO804
OT12 flat array

mj90210
Posts: 10
Joined: Fri Feb 03, 2017 2:12 pm
Location: Montana-USA

Re: Vibration/Loose Brace

#3 Post by mj90210 » Sat Oct 21, 2017 6:34 pm

Update! I tried “listening” all over for the vibration but no real luck. I decided to pull one driver so I could hear or see something better. I pulled the driver and let the other driver play a test tone, then I pushed down on panel 3 and it instantly went away. Upon further inspection the middle 3/6 brace was loose, really not loose...but you can feel the glue seam separated. When I mounted a driver, I used a lag type screw and when it passed through the mounting blocks it barely touched the middle 3/6 brace creating a push pull effect. I noticed this when I was torquing them down so I ground off 3/8” so it didn’t protrude...but damage was done. Good news, easy fix with some PL and screws from the chamber and access/storage chamber.

Lesson learned, pay close attention and document brace installation or be consistent with measurements...just in case you have to come back and put screws in braces blindly or maybe put a couple in just to establish the line. For how much time goes into these cabinets no shortcuts should be taken. I built all four methodically at the same time to in a stepped type construction. I felt like rain man with the planning and construction sequencing AND I still wished I would of done some steps differently... I will submit somewhat lengthy build post soon. Thanks for the reply!
Thank You All for Your Time!!...Really!

Built:
4xDual-30” Tuba 60’s
1x20” THT
TrT 10" Driver-10" Wide

chrisj360
Posts: 102
Joined: Fri Sep 20, 2013 1:37 pm
Location: Bellingham, WA

Re: Vibration/Loose Brace

#4 Post by chrisj360 » Sat Oct 21, 2017 10:12 pm

Good to hear it was an easy find & fix. I can only imagine how stressful that would be thinking about ripping it open.
2 x 21" T30's with Lab12's
2 x 28" T30's with Lab12's
2 x OTop12 with Deltalite 2512

User avatar
Tom Smit
Posts: 6385
Joined: Sat Jan 05, 2008 1:24 pm
Location: Sarnia, Ont. Canada

Re: Vibration/Loose Brace

#5 Post by Tom Smit » Sun Oct 22, 2017 9:21 pm

:clap:
TomS

Rich4349
Posts: 601
Joined: Wed Jul 30, 2008 10:18 am
Location: Kankakee, IL

Re: Vibration/Loose Brace

#6 Post by Rich4349 » Wed Oct 25, 2017 3:36 pm

Is that just your user name, or are you really in SoCal?
2 DR250s, 2 27" Lab15 T-60s, 2 30" Neo Titan 39s, 1 Autotuba...and looking for more!

User avatar
Padde298
Posts: 78
Joined: Thu Jun 29, 2017 5:04 am
Location: Denmark

Re: Vibration/Loose Brace

#7 Post by Padde298 » Fri Oct 27, 2017 1:12 am

mj90210 wrote: I will submit somewhat lengthy build post soon.
Looking forward to this... :clap:
More bass, more bass! :chainsaw: :chainsaw:

2 x TAT

Post Reply