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Author Topic: Suitability of 2 LABs for a smallish venue  (Read 6273 times)

davidsavill

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Suitability of 2 LABs for a smallish venue
« on: October 04, 2017, 09:49:02 pm »

Hi All

I have searched through the forums but can't find an answer which matches our use case.

I am looking at building 2 LABs for a small venue, it's basically a box 7.5m x 7.5m (~55m2), music is pretty mixed but ranged from top 40 to techno and house nights.

The first question is whats are peoples views on how 2 LABS will perform in a small space like this? There seem to be mixed views on how well these subs do in small spaces in various forums - has anyone had experienced 2 x labs in a room this size?

I wonder if they would be best corner loaded, one each side, or stacked in the middle somewhere.

Finally... whats a recommended in terms of watts per box in this environment, say if they were all parallel or series/parallel

Thanks all!
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Art Welter

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Re: Suitability of 2 LABs for a smallish venue
« Reply #1 on: October 05, 2017, 08:46:40 pm »


1)The first question is whats are peoples views on how 2 LABS will perform in a small space like this?
2)There seem to be mixed views on how well these subs do in small spaces in various forums - has anyone had experienced 2 x labs in a room this size?
3)I wonder if they would be best corner loaded, one each side, or stacked in the middle somewhere.
4)Finally... whats a recommended in terms of watts per box in this environment, say if they were all parallel or series/parallel

Thanks all!
David,
1) Assuming you mean the Tom Danley designed LAB Sub, and build the complicated FLH cabinet properly, it should perform well.
2) The "mixed views" are usually from people that mistake room modes and nodes for cabinet response. A bad room (square is bad, cubical worst ;^) ) will sound bad with FLH (front loaded horns) TH (tapped horns) or BR (bass reflex) cabinets.
3) Define "best"- each position mentioned has positive and negative sound consequences.
4) Each LAB 12 driver is capable of 400 watts long term. The minimum impedance of the LAB 12 in most any cabinet design is it's DCR (4.29 ohms) at FB, so when used in parallel look for an amp that is solid at 2 ohms.    EDM often has as little as 3 dB crest factor, so an RMS limiter should be set to no more than 41.4 volts (400 watts per driver). With dynamic music content, 1000 watt peaks, around 66 volts are no problem.
The near 20 year old LAB 12 design is not good at getting rid of heat, and putting those drivers in a little sealed back chamber makes them exhibit a high degree of thermal compression.

Art

« Last Edit: October 05, 2017, 08:51:42 pm by Art Welter »
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Rob Spence

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Re: Suitability of 2 LABs for a smallish venue
« Reply #2 on: October 05, 2017, 09:32:11 pm »

David, consider Artís Keystone sub. Might be a little less challenging from a woodworking perspective and is a bit smaller.


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Art Welter

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Re: Suitability of 2 LABs for a smallish venue
« Reply #3 on: October 06, 2017, 11:52:08 am »

David, consider Artís Keystone sub. Might be a little less challenging from a woodworking perspective and is a bit smaller.
Thanks for the props!

The Keystone is only 26.8 cubic feet net, compared to a LAB sub at 41.4 cubic feet.
The new Keystone "B-Low" is 29.5 cubic feet, testing results should be done by next week, assuming I can get around a software "upgrade" problem that has made Smaart V6 not function properly.

Art
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John Chiara

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Re: Suitability of 2 LABs for a smallish venue
« Reply #4 on: October 06, 2017, 12:39:44 pm »

Hi All

I have searched through the forums but can't find an answer which matches our use case.

I am looking at building 2 LABs for a small venue, it's basically a box 7.5m x 7.5m (~55m2), music is pretty mixed but ranged from top 40 to techno and house nights.

The first question is whats are peoples views on how 2 LABS will perform in a small space like this? There seem to be mixed views on how well these subs do in small spaces in various forums - has anyone had experienced 2 x labs in a room this size?

I wonder if they would be best corner loaded, one each side, or stacked in the middle somewhere.

Finally... whats a recommended in terms of watts per box in this environment, say if they were all parallel or series/parallel
Thanks all!
Where are you located?
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davidsavill

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Re: Suitability of 2 LABs for a smallish venue
« Reply #5 on: October 06, 2017, 04:49:28 pm »

Thanks Art for getting back to me

The plans I have are the 18mm drawings here... http://www.prosoundweb.com/lsp I have heard there are different versions but these seem to be the most complete.

The room dimensions are not great, I agree. The punters are up close to the PA and then back to 4-5m, so "best" would be them experiencing as quality a sound in this middle zone as possible.

The heat was a concern with some of the music we get. I think you're saying even at 400w we might still have issues?


David,
1) Assuming you mean the Tom Danley designed LAB Sub, and build the complicated FLH cabinet properly, it should perform well.
2) The "mixed views" are usually from people that mistake room modes and nodes for cabinet response. A bad room (square is bad, cubical worst ;^) ) will sound bad with FLH (front loaded horns) TH (tapped horns) or BR (bass reflex) cabinets.
3) Define "best"- each position mentioned has positive and negative sound consequences.
4) Each LAB 12 driver is capable of 400 watts long term. The minimum impedance of the LAB 12 in most any cabinet design is it's DCR (4.29 ohms) at FB, so when used in parallel look for an amp that is solid at 2 ohms.    EDM often has as little as 3 dB crest factor, so an RMS limiter should be set to no more than 41.4 volts (400 watts per driver). With dynamic music content, 1000 watt peaks, around 66 volts are no problem.
The near 20 year old LAB 12 design is not good at getting rid of heat, and putting those drivers in a little sealed back chamber makes them exhibit a high degree of thermal compression.

Art
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davidsavill

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Re: Suitability of 2 LABs for a smallish venue
« Reply #6 on: October 06, 2017, 04:50:10 pm »

Where are you located?

Near Sydney, Aus
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davidsavill

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Re: Suitability of 2 LABs for a smallish venue
« Reply #7 on: October 06, 2017, 05:33:46 pm »

Thanks Rob - have heard good things about the Keystone. I suppose we could grab some Lab12 drivers and try both. Seems they work in both cabs.

The woodworking doesn't daunt me too much on any of these and am happy with having something the size of a lab if it will suit the use case. Couldn't to more than two though both with space and budget.


David, consider Artís Keystone sub. Might be a little less challenging from a woodworking perspective and is a bit smaller.


Sent from my iPad using Tapatalk Pro
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Art Welter

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Re: Suitability of 2 LABs for a smallish venue
« Reply #8 on: October 06, 2017, 05:39:26 pm »

The heat was a concern with some of the music we get. I think you're saying even at 400w we might still have issues?
With a RMS limiter set to no more than 41.4 volts (400 watts per driver) LAB 12s should be OK, though they will be running damn hot with some types of EDM, especially if the drone happens to be at the impedance minima at Fc, where the cone moves very little, but draws the most power. It would be safer to drop it to half that power, 29 volts.

Peak limiting around 66 volts still would be no problem.
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Art Welter

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Re: Suitability of 2 LABs for a smallish venue
« Reply #9 on: October 06, 2017, 05:47:05 pm »

Thanks Rob - have heard good things about the Keystone. I suppose we could grab some Lab12 drivers and try both. Seems they work in both cabs.

The woodworking doesn't daunt me too much on any of these and am happy with having something the size of a lab if it will suit the use case. Couldn't to more than two though both with space and budget.
If you decide on the Keystone, use the suggested 18" B&C drivers- although they are a tad less sensitive, they get rid of heat far better, so end up being louder than the LAB 12" due to less power compression.

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