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Author Topic: So much lowend even a solid state drive skips  (Read 6663 times)

Scott Carneval

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Re: So much lowend even a solid state drive skips
« Reply #10 on: January 04, 2016, 12:16:15 pm »

What about the DJ control interface? Turntables? CDJ's? Fisher Price My First DJ Controller?

Even the digital controllers have pressure sensitive platters, so they could have been freaking out from the bass. Every MacBook Pro I've ever opened has shock-mounted HDD, so I really doubt that's the issue. Most DJ's I know either set their laptop on the neoprene sleeve they carry it in, or use a stand to reduce the vibration.
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Franklin Benjamin

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Re: So much lowend even a solid state drive skips
« Reply #11 on: January 04, 2016, 12:28:17 pm »


Try going cardioid. It should reduce the low end energy on stage.   I doubt power caused the issue even though the power connector is magnetic, battery should still be supplying steady power.  Unless the continuous vibration of the connector causes it to crash.

I couldn't really tell. What subs are you using?
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Stephen Kirby

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Re: So much lowend even a solid state drive skips
« Reply #12 on: January 04, 2016, 01:16:22 pm »

Having the subs in an arc like that means that there is a very focused concentration of sound at the center of the arc, in the rear of the subs.  I've seen some MAAP plots of various arc configurations and if you had the DJ booth behind those near the apex of the arc, that was the highest SPL of the entire rig.

I work with a bunch of ex-Apple engineers including several reliability engineers.  They do test the computers under pretty substantial vibration but possibly not what those were seeing in that situation.  They also do bunches of shock loading tests on the connectors to make sure someone tripping on a cord doesn't break anything in the computer.  Which is not to say that a USB type A connector might not glitch under severe vibration.  The design was developed to maintain characteristic impedance rather than use in a helicopter. 
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brian maddox

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Re: So much lowend even a solid state drive skips
« Reply #13 on: January 04, 2016, 01:19:45 pm »

...NASA has a PA system to do this for payload testing. It would suck if the processor controlling something important in a rocket ship crashed due to launch pad vibration...

Ed Walters

Yes they do.  I've seen it.  It's pretty impressive...  :)

Maybe Apple needs to borrow it for a test.  :)
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Jim McKeveny

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Re: So much lowend even a solid state drive skips
« Reply #14 on: January 04, 2016, 01:29:13 pm »

Since new Mac books have no moving parts..

Keys?
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Craig Hauber

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Re: So much lowend even a solid state drive skips
« Reply #15 on: January 04, 2016, 01:36:47 pm »

A related thought - in the transition from spinning disks to SSDs, a number of machines still have accelerometers that are designed to park the disk heads if the machine takes a tumble.  I don't know how much of this vestigial functionality exists in the machines you use, but it can happen.

Your only solutions will be things that reduce the vibration to your machines - either by isolating your computers, or by acoustical techniques to reduce bass on the DJ platform - cardioid subs, etc.
Yes -what Tom said-  pretend it's the 70's, 80's and even the 90's again and act like you have turntables (that actually playback the music -yes kids they actually used to do that :-)
I remember all the shenanigans that DJ's used to go through to keep LF from feeding back through the turntables and all the cushions, foam, patio slabs, hanging springs etc.. -some of it would actually work :-)

Other ideas to look into:

-Check the power as John suggested, but with an older needle-style meter that you can actually see pulses -usually a handheld digital meter won't respond fast enough to see the surges from the sub amp's draw.  (the bargraph display on older furman rack light units in FOH racks was great for seeing this)

-From your pictures it looks like the subs are behind the DJ firing through a screen? 
Put the bass on the dancefloor not the DJ booth! Isolate the conducted mechanical vibration from the stage/riser/whatever that the DJ is set-up on.

-try to "cardiod" your setup just enough to get a cancellation right at the DJ table. 

-Fire-up a tone generator and walk the room -you'll hear/feel nodes and dead spots, try to place the DJ in one of the dead spots!  you could go as far as to move the subs to separated blocks to even force cancellation spots.

Also make sure your not killing other spots in the club -I once rattled a bar so much a glass shelf walked off it's mounting, collapsed and dumped the entire top-shelf row onto the floor -including the bottle of Louis XIII -luckily the display case kept bottle from shattering but it dumped out over 3/4 of it :-(
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Hayden J. Nebus

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Re: So much lowend even a solid state drive skips
« Reply #16 on: January 04, 2016, 05:07:17 pm »

I guess my question is, what is a practical way to avoid this in the future? The foam helped but not as much as it could of helped. I'm sure if I ran into this problem someone else ran into this problem. Are there any solutions out there, commercial or diy? Granted the foam, but anything else?

Something like an old-school turntable sandbox isolator might work and is a cheap DIY. you need a 5 sided box, a float plate that fits inside the box without touching the walls, and a bag of play sand. For extra isolation, you can make 6 feet out of 3 racquetballs cut in half and attach to the box.
 
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Len Zenith Jr

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Re: So much lowend even a solid state drive skips
« Reply #17 on: January 04, 2016, 05:44:04 pm »

What kind of SPL would you figure was at the DJ table?
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Dave Jones

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Re: So much lowend even a solid state drive skips
« Reply #18 on: January 05, 2016, 04:02:41 am »

As everything else has been eliminated, I'm betting that vibrations somehow triggered keyboard keystrokes or trackpad clicks which caused the randomness.

Dave.
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Stephen Kirby

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Re: So much lowend even a solid state drive skips
« Reply #19 on: January 05, 2016, 01:01:11 pm »

Asked one of the ex-Apple folks who worked on these and with the force required to actuate the key switches, it's highly unlikely that vibration would cause an actuation.
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Re: So much lowend even a solid state drive skips
« Reply #19 on: January 05, 2016, 01:01:11 pm »


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