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Author Topic: SB1000 Flipped on Sides  (Read 656 times)

Griffen Behm

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SB1000 Flipped on Sides
« on: July 02, 2020, 02:40:26 am »

I've done a quick search on this - makes sense that most subs don't care what their orientation is for operation.

In the case of the SB1000 with it's clamshell configuration of the drivers, would this still be the case? I'm thinking that if flipped 90deg on it's side, the drivers would be influenced by gravity differently at a given time - could this result in a phase issues or driver strain that would be significant enough to be concerned about?

In my current application I'd be able to squeeze a few more cabinets into the given area by doing so, but if it has negative implications I'll explore some other options.

Thanks,
-Griffin
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Chris Grimshaw

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Re: SB1000 Flipped on Sides
« Reply #1 on: July 02, 2020, 03:24:13 am »

Short-term, it'll be fine.

Long-term, you've got the risk of cone sag setting in. Turning the cabs over once per year will probably keep on top of it, or you could implement a small DC power supply that provides a holding force against gravity.

Chris

Edit - Here's a link to relevant discussion: https://forums.prosoundweb.com/index.php/topic,166841.msg1538596.html#msg1538596
« Last Edit: July 02, 2020, 03:26:55 am by Chris Grimshaw »
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Griffen Behm

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Re: SB1000 Flipped on Sides
« Reply #2 on: July 02, 2020, 04:07:48 am »

Short-term, it'll be fine.

Long-term, you've got the risk of cone sag setting in. Turning the cabs over once per year will probably keep on top of it, or you could implement a small DC power supply that provides a holding force against gravity.

Chris

Edit - Here's a link to relevant discussion: https://forums.prosoundweb.com/index.php/topic,166841.msg1538596.html#msg1538596

Hey Chris,

Thanks, that makes sense. Should have mentioned this is for a one-off so they'll only be subjected to it for half a day. Interesting thought on the DC power to maintain them in a permanent situation however.

Thanks,
-Griffin
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MikeHarris

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Re: SB1000 Flipped on Sides
« Reply #3 on: July 02, 2020, 06:57:00 am »

i think the clamshell design benefits from the long side against the ground...should couple better.
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Matthew Knischewsky

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Re: SB1000 Flipped on Sides
« Reply #4 on: July 02, 2020, 11:07:25 am »

I've done a quick search on this - makes sense that most subs don't care what their orientation is for operation.

In the case of the SB1000 with it's clamshell configuration of the drivers, would this still be the case? I'm thinking that if flipped 90deg on it's side, the drivers would be influenced by gravity differently at a given time - could this result in a phase issues or driver strain that would be significant enough to be concerned about?

In my current application I'd be able to squeeze a few more cabinets into the given area by doing so, but if it has negative implications I'll explore some other options.

Thanks,
-Griffin

Driver sag is a real issue. EAW KF750 has a similar "clam shell" config with 12" drivers except rotated 90 degrees - there's a top and bottom driver. They sag over time, it's easy to see which driver is which. But we're talking over the course of years...My solution was to rotate the top and bottom drivers whenever I was servicing a cabinet to "even them out". When the sag became a problem it would show up as a buzzy sound in the LF driver sweep test. The other option is re-coning and that gets expensive quickly.

At least with SB1000s you could periodically flip the entire cabinet if this is for an install. For portable use I wouldn't worry about it. As far as which orientation produces better sound, for an SB1000 it doesn't matter.
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Don T. Williams

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Re: SB1000 Flipped on Sides
« Reply #5 on: July 02, 2020, 06:37:01 pm »

i think the clamshell design benefits from the long side against the ground...should couple better.

My guess that unless you are arraying a fairly large number of cabinets (approaching 1/2 wavelength) there would probably be little difference.  In theory you are probably correct!
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Ivan Beaver

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Re: SB1000 Flipped on Sides
« Reply #6 on: July 03, 2020, 09:30:22 am »

i think the clamshell design benefits from the long side against the ground...should couple better.
That design has more to do with fitting the drivers in the cabinet than any acoustical performance.

You have to think in terms of wavelengths.  At the wavelengths the cabinet is intended to operate, the dimensions of the "clamshell" are simply to small to make any difference.

A general rule is 1/4 wavelength or larger to make any difference.  Since 50Hz is around 20' long, 1/4 wavelength is 5'.  So things 5' or larger would matter.  The distances in the clamshell are no where near that.
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Peter Morris

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Re: SB1000 Flipped on Sides
« Reply #7 on: July 03, 2020, 10:21:09 am »

That design has more to do with fitting the drivers in the cabinet than any acoustical performance.

You have to think in terms of wavelengths.  At the wavelengths the cabinet is intended to operate, the dimensions of the "clamshell" are simply to small to make any difference.

A general rule is 1/4 wavelength or larger to make any difference.  Since 50Hz is around 20' long, 1/4 wavelength is 5'.  So things 5' or larger would matter.  The distances in the clamshell are no where near that.

Well ... you will get a bit of gain from the loading caused by the slot, it will behave like a 6th order band pass with one section tuned to about 200Hz and the other 35Hz ... think in terms of 2 - 3 dB at 100Hz and 7 dB at 200Hz

Here is the frequency response plot of the SB1000 and a SIM of a double 18 reflex (grey)  and with a similar sized slot (black)
« Last Edit: July 03, 2020, 10:26:36 am by Peter Morris »
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Re: SB1000 Flipped on Sides
« Reply #7 on: July 03, 2020, 10:21:09 am »


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