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Smallest 2x12 Cabinet

#101
Pfft. Mine has a 3" super woofer and an 18" midrange. It goes down to 1 hz and has 126.7dB sensitivity. It's proprietary trampoline suspension and latex surround allow for a 40mm excursion. It has a 7 inch voice coil and a hemp and horsehair cone. I'm taking over the world. 2x12? Phshaw.
 
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#105
CL400Peavey said:
It isnt that they are specifically less efficient, its that only one of those drivers in producing sound. So you pay for, and carry around two drivers, with the output of one.
Click to expand...

They negative is they are considerably less efficient, upside: space saving but both drivers most certainly are producing sound.
 
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#108
Just popped in here...wow, I feel kinda bad for the poor OP :)

I've only ever (co) designed 3 different cabs, none of which are for sale at this time. My main criteria is I won't release a design that's too close to anything that's already out there, which ain't so easy these days. The top designers are so gifted and are pushing the current tech about as far as it can be pushed. The buyer just needs to pick a preferred flavor.

Real specs vs marketing? Practically everyone does it to show real or perceived advantages for their products. Except Duke, possibly! He's most likely the best designer and worst marketer on this site :) I've had the pleasure of playing Dukes cabs and if I ever tell you I've designed something 'better' you'll know I'm lying. All I can claim is to have designed something different :)

Hopefully the OP will find the cab he's looking for!
 
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#110
funkboy5 said:
You might wanna try a single 115. I recently purchased 2 Bugera 115's and they sound great and great bang for the buck $299. Nothing like a good 115. Good luck.
Click to expand...

I know the thread has diverged hugely since this post.

I have done a lot of gigs with a single TL style 15" cabinet. I have never known them to be lacking in volume while still being compact.

They may not be quite as much surface area as a 2x12, but it isn't really a massive difference.
 
#111
dawind99 said:
No, once again, you do not. It is based on driver alignment of which there are 3 that are widely used with different results and for different applications. But there could be, I believe, more to be explored.
Click to expand...

Below the most common used Isobaric configurations

1.sealed
  • sealed push/pull (clamshell)
  • sealed with increased coupling chamber
  • sealed with increased coupling chamber + push /pull
2. ported
  • ported push/pull (clamshell)
  • ported with increased coupling chamber
  • ported with increased coupling chamber + push /pull
With the push/pull (clamshell) configuration the coupling volume is smallest, this one won't change fs (just very, very slightly due to air mass increase) and will act the same as the single driver variant but with 1/2 Vas. Due to the small coupling volume the coupling between the two drivers is "stiff". The clamshell push/pull configuration decreases 2nd order harmonic distortion (due to decreasing the asymmetry in the suspension).

When you increase the coupling chamber you add air mass (which alters the Fs, but also Vas, Qms and Qes). The coupling between the two drivers gets less stiff when increasing the coupling volume, this can create "unpredictable" results in how the total system will behave (you probably need ACABAC or some other powerful tool to predict the outcome. Such an alignment may even increase the total harmonic distortion due to increased asymmetry.

Output wise there isn't much to be gained with either of these configurations since the cone area and volume displacement don't change.
 
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#112
Wow a lot more info since last night. I think some may have thought I was making light of the discussion. I'm not in fact I love this stuff in spite of the fact much of t is over my head I read it all and try to wrap my head around the science. I try to educate myself as much as possible exactly to make as informed a decision as I can. Now I have to go back a couple of pages and reread and redigest this stuff. And thank you to some of our best and brightest minds on the subject for weighing in. You guys rock! I enjoy a Good and thorough pummeling with science. Carry on.
 
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#113
dawind99 said:
No, once again, you do not. It is based on driver alignment of which there are 3 that are widely used with different results and for different applications. But there could be, I believe, more to be explored.
Click to expand...

As is highlighted:

Arjank said:
Output wise there isn't much to be gained with either of these configurations since the cone area and volume displacement don't change.
Click to expand...

In the simplest of terms, you get sound by moving air. If you have a driver that is not moving air that is incident to your ear drum, then you wont hear it. That doesnt mean it wont change the specs of the system and change the sound, but your total output is not increased by a driver that is moving sealed up behind another.


The two drivers operating in tandem exhibit exactly the same behavior as one loudspeaker in twice the cabinet. The cabinet is defined as the space behind the rear driver. The volume of air between the speakers has no acoustic function so that the saved space is less than 50%. All other aspects are unchanged like resonant frequency and maximum SPL. The new driver will have the same resonance frequency, Qts, distortion, excursion etc. as one driver with the same applied signal. Because the impedance is also halved, this performance is achieved with twice the power. The new efficiency is thus 3 dB lower than with one loudspeaker. The reason for the unchanged resonance frequency is simple: the new combined loudspeaker has twice the moving mass compared to the single driver but also half the compliance because of the doubled suspension.
Click to expand...

So you end up with a small box, that is inefficient, and has the output of a single driver.
 
#114
Arjank said:
Below the most common used Isobaric configurations

1.sealed
  • sealed push/pull (clamshell)
  • sealed with increased coupling chamber
  • sealed with increased coupling chamber + push /pull
2. ported
  • ported push/pull (clamshell)
  • ported with increased coupling chamber
  • ported with increased coupling chamber + push /pull
With the push/pull (clamshell) configuration the coupling volume is smallest, this one won't change fs (just very, very slightly due to air mass increase) and will act the same as the single driver variant but with 1/2 Vas. Due to the small coupling volume the coupling between the two drivers is "stiff". The clamshell push/pull configuration decreases 2nd order harmonic distortion (due to decreasing the asymmetry in the suspension).

When you increase the coupling chamber you add air mass (which alters the Fs, but also Vas, Qms and Qes). The coupling between the two drivers gets less stiff when increasing the coupling volume, this can create "unpredictable" results in how the total system will behave (you probably need ACABAC or some other powerful tool to predict the outcome. Such an alignment may even increase the total harmonic distortion due to increased asymmetry.

Output wise there isn't much to be gained with either of these configurations since the cone area and volume displacement don't change.
Click to expand...

A, well described. I'm assuming by (clamshell) you are referring to the driver alignment cone to magnet and push/pull = drivers wired out of phase. The 3d is just the opposite of the "clamshell" with drivers mounted back to back (magnet to magnet). All are of no use in my opinion and especially so in this day and age "super-drivers" compared to what was available 30 years ago when something like a Gauss was a big deal to some folks. Another flaw of isobarics is the inability to find a perfectly matched set of drivers and provide them an environs that allows their voice coils maintain the same temperature as gradients change within the cabinet causing changes in sensitivity/resistance changes in the voice coils and adding distortion. Thanks for not quoting Wikepedia:)
 
#115
CL400Peavey said:
As is highlighted:



In the simplest of terms, you get sound by moving air. If you have a driver that is not moving air that is incident to your ear drum, then you wont hear it. That doesnt mean it wont change the specs of the system and change the sound, but your total output is not increased by a driver that is moving sealed up behind another.




So you end up with a small box, that is inefficient, and has the output of a single driver.
Click to expand...

There is more information available then what quoted sans quotation marks from Wikipedia. I you were interested in learning more about isobarics there more in depth and enlightening resources. The history of cabinet design wasn't originally based in science. Without a balance of trust in science and the human ear design progress would come to a standstill.
 
#116
dawind99 said:
There is more information available then what quoted sans quotation marks from Wikipedia. I you were interested in learning more about isobarics there more in depth and enlightening resources. The history of cabinet design wasn't originally based in science. Without a balance of trust in science and the human ear design progress would come to a standstill.
Click to expand...

Wiki is quick and easy to quote from my phone, and all the work this discussion deserves. It also uses language that the average reader isnt going to glaze over while reading. I trust my ears, and don't find iso cabs to have as much output as single driver cabs with better designs. That said, I trust measurements as perception of added distortion can trick you in to interpreting it as louder.
 
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#117
dawind99 said:
A, well described. I'm assuming by (clamshell) you are referring to the driver alignment cone to magnet and push/pull = drivers wired out of phase. The 3d is just the opposite of the "clamshell" with drivers mounted back to back (magnet to magnet).
Click to expand...
The "clamshell" push/pull is when you mount the drivers cone-cone, in this case the coupling volume is the smallest.
We indeed have another version of the push/pull and that's magnet-magnet :)

dawind99 said:
All are of no use in my opinion and especially so in this day and age "super-drivers" compared to what was available 30 years ago when something like a Gauss was a big deal to some folks. Another flaw of isobarics is the inability to find a perfectly matched set of drivers and provide them an environs that allows their voice coils maintain the same temperature as gradients change within the cabinet causing changes in sensitivity/resistance changes in the voice coils and adding distortion.
Click to expand...
Indeed, this also adds asymmetry and thus distortion :thumbsup:
Best would be the magnet-magnet option (provided that the drivers don't have a porous dustcap or phase-plug) and with an as small as possible coupling volume. In this case 2nd order harmonic distortion can be lower then that of a single driver.


dawind99 said:
Thanks for not quoting Wikepedia:)
Click to expand...
Thnx, I don't need that for anything regarding loudspeakers ;)
 
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