T48 Rattle/Buzz

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njkreger
Posts: 77
Joined: Sat Jun 16, 2018 6:45 am

T48 Rattle/Buzz

#1 Post by njkreger » Sun Nov 18, 2018 2:15 pm

Hi, we've recently finished two T48s. I set limited yesterday, wired them up, and ran a track through it to hear them. One of the T48s has a rattle or buzzing sound. I can't quite isolate it yet, and it's pretty prominent when a run a 60Hz + sine wave through it and start to turn the volume up. Where should I start troubleshooting this?

Thanks!

jimbo7
Posts: 543
Joined: Fri Dec 28, 2012 10:45 am
Location: St. Louis

Re: T48 Rattle/Buzz

#2 Post by jimbo7 » Sun Nov 18, 2018 4:05 pm

1. is it air tight?
2. cover screws tight?
3. jack plate tight?
4. speaker screws tight?
5. wires/crossover rattling around?
6. if above don't solve it you probably have a loose brace. good luck with that.
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
2x OT12 flat array
2x SLA Pro 2-Alpha 6's 2-Goldwoods

CoronaOperator
Posts: 1485
Joined: Wed Mar 25, 2009 7:07 pm
Location: Medicine Hat, Alberta, Canada

Re: T48 Rattle/Buzz

#3 Post by CoronaOperator » Sun Nov 18, 2018 4:15 pm

Try the taking driver access plates off and see if the driver is hitting the opening. Then run your sine wave and make it rattle, then try pressing down, sitting on different parts of the cab to see if you can make it stop. That might help you locate the source.
Built:
17" width 10" driver Autotuba
2 x 29" width dual Lab12 Tuba60
6 x DR250 2510/asd1001
In progress:
2 x DR250 2510/asd1001
For best results, point the loud end of the array towards the audience

njkreger
Posts: 77
Joined: Sat Jun 16, 2018 6:45 am

Re: T48 Rattle/Buzz

#4 Post by njkreger » Sun Nov 18, 2018 6:29 pm

jimbo7 wrote:
Sun Nov 18, 2018 4:05 pm
1. is it air tight?
2. cover screws tight?
3. jack plate tight?
4. speaker screws tight?
5. wires/crossover rattling around?
6. if above don't solve it you probably have a loose brace. good luck with that.
I leak checked around the whole cab and it’s airtight, as is the cover and the terminal strip. I screwed the driver in and compressed the gasket, waited a day and tightened them again, so I’m pretty confident they’re good. I’ll probably have to check the wiring, so I’ll have another go at the speaker. Hopefully not a loose brace. :(

njkreger
Posts: 77
Joined: Sat Jun 16, 2018 6:45 am

Re: T48 Rattle/Buzz

#5 Post by njkreger » Sun Nov 18, 2018 6:30 pm

CoronaOperator wrote:
Sun Nov 18, 2018 4:15 pm
Try the taking driver access plates off and see if the driver is hitting the opening. Then run your sine wave and make it rattle, then try pressing down, sitting on different parts of the cab to see if you can make it stop. That might help you locate the source.
Thanks! I’ll do that this week and report back...

Preston
Posts: 178
Joined: Mon Apr 14, 2008 3:59 pm
Location: Springfield, IL

Re: T48 Rattle/Buzz

#6 Post by Preston » Thu Dec 06, 2018 10:36 am

I had a similar problem with a T39. I cut the hole driver spacer too small and the cone was hitting it. Might want to pull the driver and check.

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Chris_Allen
Posts: 3219
Joined: Wed Jul 11, 2007 2:43 pm
Location: Huddersfield, UK

Re: T48 Rattle/Buzz

#7 Post by Chris_Allen » Fri Dec 07, 2018 8:35 am

The chalk test round the edge of the spacer will tell you if the driver is hitting it. It's time consuming taking the driver in and out but it's worth it for the piece of mind alone.
Built:
6xDR200, 2xT39, 2xT48, 2xJack110, 1xOmni10.5, 1xAutotuba, 1xT18, 1xSLA Pro, 1xW8, 1xW10

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