Build your own 2x12" TH (The Kraken 212 TH)

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Petter Persson

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Joined 2007
Sorry to hear Andrew. Can you please tell what you mean so I
understand you and can explain eventual uncertainties.

Hi Petter, in real world terms how much more distortion will the 112 have compared to the 212?

At which part of the frequency range will it be noticeable? For example if I used it for movies would it be more noticeable?

If I critically listen to well recorded double bass will it be noticeable?

The problem is I've never heard a large horn sub with 2 drivers in push pull config compared to 2 smaller horn subs with a single drivers so I would be interested in your opinion on this.

Thanks in advance
DJ
Click to expand...


Sorry I have not made or heard either the Kraken 112 or 212. It is mostly the
second harmonics that are canceled by the push pull configuration. How
much depends from case to case but I have seen figures of about 10 dB
reduction across the whole freq- range. If your room is resonant in the
bass, you probably benifit more from two boxes to cancel room resonances
than one box to reduce distorsion.
 
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18Hurts

Member
Joined 2010
Petter Persson said:
If your room is resonant in the
bass, you probably benifit more from two boxes to cancel room resonances
than one box to reduce distorsion.
Click to expand...

Thank you Petter,

I have one JBL driver sitting on a shelf waiting for the time to build a 112. Figure two of them, one for each side would be better in my garage to limit
shaking the metal walls. Once the output gets to a level where distortion would be an issue, the walls will add their own sound to drown that out. :eek:

The line arrays don't shake the walls at realistic volumes and eliminate cement floor and metal roof reflections. I know bass goes omni-directional but am crossing my fingers that a 112 won't create too much pressure in a
corner. The inner walls of the garage are plywood and I plan on putting in some form of insulation between the plywood inner walls, wood studs and isolate the outer metal walls. Initial plan is to fill the space with fiberglass and rubber tires in the corners.

Once the wall prep is done, I guess I could keep building 112's to even out the pressure along the wall? Does a horn have less pressure behind it at the same output than a sealed or ported sub? My seated position is 11 feet (3.3 meters) away and all tricks are accepted.
 
weltersys

weltersys

Member
Joined 2008
18Hurts said:
I know bass goes omni-directional but am crossing my fingers that a 112 won't create too much pressure in a
corner.
..I guess I could keep building 112's to even out the pressure along the wall? Does a horn have less pressure behind it at the same output than a sealed or ported sub? .
Click to expand...
Corner placement will maximize the sound pressure level in that location.
Multiple sources reduces localized SPL.
A large mouth horn will have more directivity in the upper range (60 Hz or so up) than a sealed or ported sub of the same frontal dimensions, so will create (slightly) less SPL behind it.
Below 60Hz, (the wall flopping trouser leg flapping range), unless you have a wall of cabinets they will have little directivity.

I wish I would have insulated and sheet rocked my wood shop when I built it, high SPL low bass flops the walls, reducing LF level inside, and transmits it with little reduction in level to the outdoors.

If you want serious bass in your garage, I'd suggest finishing it before adding a boatload of subs.

P.S. My wood shop walls are made of SmartSiding, a 5/16" OSB material, (roughly) 100 times better than sheet metal as far as not flopping and rattling. The smaller "electronics" portion of the shop is finished, but has metal exterior walls. Other than tools hanging on the wall making vibration noises, it sounds far better than the wood shop when playing high SPL VLF.

Art
 
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18Hurts

Member
Joined 2010
weltersys said:
A large mouth horn will have more directivity in the upper range (60 Hz or so up) than a sealed or ported sub of the same frontal dimensions, so will create (slightly) less SPL behind it.
Below 60Hz, (the wall flopping trouser leg flapping range), unless you have a wall of cabinets they will have little directivity.

If you want serious bass in your garage, I'd suggest finishing it before adding a boatload of subs.

P.S. My wood shop walls are made of SmartSiding, a 5/16" OSB material, (roughly) 100 times better than sheet metal as far as not flopping and rattling. The smaller "electronics" portion of the shop is finished, but has metal exterior walls. Other than tools hanging on the wall making vibration noises, it sounds far better than the wood shop when playing high SPL VLF.

Art
Click to expand...

Thanks for the tips, Art. The garage is very solidly built but not for music, for working on various things. The chain hoist can hold up those large tapped horns. :cool:

The Kraken 112 should assist me with low frequency troubleshooting and will only have a 120 watt amp initially. The second 112 will require a new amp so I'm sure that will make the garage door a very large passive radiator. The SPL limit in the garage is that large door which might have issues with one Kraken 112. The second one would be for sound quality, lowering distortion
and better balance--not for increased SPL.

Just having 105 dB mains and 115dB sub levels would be great if I can keep the garage from turning into a rattle can. I can always stuff it under the couch in case the door flexes too much.
 
weltersys

weltersys

Member
Joined 2008
18Hurts said:
The Kraken 112 should assist me with low frequency troubleshooting and will only have a 120 watt amp initially. The second 112 will require a new amp so I'm sure that will make the garage door a very large passive radiator. The SPL limit in the garage is that large door which might have issues with one Kraken 112. The second one would be for sound quality, lowering distortion
and better balance--not for increased SPL.
Click to expand...
Lab 12s are only 4.29 ohms DCR (and at the cabinet's impedance minima), a pair in series will still give you a tad more output than one on most amplifiers.

The Lab 12 THD at 120 watts will be only a few percent at most, the vibrating metal walls and garage door distortion may exceed 100% with 120 watt input :h_ache:.
 
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