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Author Topic: AES50 dropout during subharmonics/anything under sustained 50hz  (Read 1937 times)

Jason Branden

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #10 on: May 15, 2018, 03:53:31 pm »

OP stated:
Troubleshooting steps taken
* measured power at amp rack to check for voltage dip. None. Rock Solid.
* measured (mains) power at supply (150A 3 phase 208) -all phases during event. -Perfect
* measured power going directly TO the DL32 -rock solid


So low voltage is not the problem.

Yeah, we put a logging meter on the rack to watch all sorts of stuff. Nothing out of the norm, unfortunately.
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Jason Branden

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #11 on: May 15, 2018, 03:54:04 pm »

The LABSub has an impedance minimum right around 40Hz, so the most current would be drawn on sustained notes at that frequency. EDM often has sustained continuous LF content, a surface resonance may be shaking the DL32 enough for the cord to loose continuity, while short "louder and punchier" peaks evidently aren't exciting the resonance enough to become problematic.

You could get an equivalent SPL of four with just one LAB Sub if you remove the grill and place the DL32 inside the mouth, do a slow sine sweep right around 40 Hz and see if the problem occurs, and determine at what specific frequency and SPL.

If it does occur, you should be able to eliminate the problem by applying pressure around the connector to dampen the resonance.


Good luck!

Art


That's actually an interesting idea!   I'll likely give that a try and see what happens. At least then I can either verify or rule out physical issues with connectors are surface mount / board issues!   Thanks!
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Tim McCulloch

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #12 on: May 15, 2018, 05:01:45 pm »


That's actually an interesting idea!   I'll likely give that a try and see what happens. At least then I can either verify or rule out physical issues with connectors are surface mount / board issues!   Thanks!

Here's my guess - it's a vibration-caused intermittent connection of an RJ45 (or one of the 8 conductors thereof) inside its EtherCon.  You might check that all of the RJ45 have the same amount of recess inside the shells, too.

"tis a puzzlement"
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Don T. Williams

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #13 on: May 15, 2018, 05:25:09 pm »

If it's not a power issue, it just has to be a vibration issue.  Is there anywhere that a cable is laying on a surface (the stage, a sub cab, a weak floor, draped in the air) where it could vibrate?  The only time I have ever lost sync was when cable was exposed to people walking or dancing on it.  Maybe the console or stage box is being vibrated enough to have a problem or a defect revealed.
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Geert Friedhof

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #14 on: May 15, 2018, 05:52:29 pm »

Here's my guess - it's a vibration-caused intermittent connection of an RJ45 (or one of the 8 conductors thereof) inside its EtherCon.  You might check that all of the RJ45 have the same amount of recess inside the shells, too.

"tis a puzzlement"

He replaced the cable, and tried port a and b...

150 feet is not too much.

I have never opened up my stageboxes. Maybe there is a loose connector somewhere?
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Jordan Wolf

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #15 on: May 15, 2018, 06:46:03 pm »

Where are your amp racks located in relation to your subwoofers?

If it is too close, I can see it getting some pretty solid vibrations. Maybe try isolating the dl32 from the rack rails and set it on top of the rack on some egg-crate foam?

Maybe placing the rack in a null might help. A 40Hz-50Hz wavelength equals about 22ft-27ft, so maybe a 1/2 wavelength between the subs and a wall?
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Jordan Wolf
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Tim McCulloch

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #16 on: May 15, 2018, 07:12:26 pm »

He replaced the cable, and tried port a and b...

150 feet is not too much.

I have never opened up my stageboxes. Maybe there is a loose connector somewhere?

The problem could exist with more than 1 connector or cable.  What the connection life of an RJ45?  IIRC it's around 2000 cycles but I could be wrong.

I don't remember the pinout of AES50 but I'm pretty sure that sync/clock is on its own pair.
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"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut

Geert Friedhof

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #17 on: May 15, 2018, 07:32:30 pm »

A dl32 can't be clock master. The M32 can be slave though...

OP? Did you check that? But if clocking is the problem it should happen always.

Edit: sorry Tim, read that wrong. You are talking about the cable pair.
« Last Edit: May 15, 2018, 07:42:55 pm by Geert Friedhof »
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Jason Branden

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #18 on: May 15, 2018, 07:37:18 pm »

The problem could exist with more than 1 connector or cable.  What the connection life of an RJ45?  IIRC it's around 2000 cycles but I could be wrong.

I don't remember the pinout of AES50 but I'm pretty sure that sync/clock is on its own pair.

Cable I replaced it with was a band new ProCo cable I keep on hand for emergencies (spare/backup)  I'm 99% sure it wasn't a cabling issue this time around. Two different cables were used for testing. (one that was only a half a year old, and one that was brand new)  dropout behavior was the same with whatever cable I used.   
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Jason Branden

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #19 on: May 15, 2018, 07:38:44 pm »

A dl32 or dl16 can't be clock master. The M32 can be slave though...

OP? Did you check that? But if clocking is the problem it should happen always.

Edit: sorry Tim, read that wrong. You are talking about the cable pair.

Yeah, clock was good. System ran top notch all four days except for the evening raves.
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