[davepete]

Kevin,
I'm definitely looking to tune lower than that.  My design goal is a freq response that's reasonably flat to the 10hz region, combined with very high SQ and output (which I haven't quantified yet, but it will probably be about 130db at the listening position).  The SQ will be achieved by selecting a driver with a linear BL design like the LMS or Sicko, and not running it past the linear limits.  I'll use as many drivers, amps, and as large an enclosure as needed to achieve that.  The enclosure will be located behind the theater in its own room, so I've got virtually no size restrictions, even for silly numbers of drivers. 

I've done some modeling using the LMS-5400 which has bad issues with ported designs when modeling 1 driver enclosure sizes.  The port resonances are unworkable, leaving PR as the only option.  I'm guess the Sicko might have similar issues.  But it appears that once you start getting into REALLY large enclosures, ~100 cu ft, using multiple drivers (8, in this case) those issues fade as you get lower tuning with shorter ports.  At least if WinISD can be believed, anyway.  Because of that, I was able to create an EBS model using 8 LMS-5400 drivers in 100cu ft that looks quite workable.  When I scale this same model down to one driver (12.5 cu ft), the 1st port resonance comes in at an appalling 19hz, but with 8 drivers and 100cu ft, it's a very acceptable 218hz.  The only parameter that looks iffy in this model is the air speed through the port, but the highest speed (68 m/s) is way down at about 9hz.  However, there isn't a whole lot of signal that low, allowing leeway there.  At 14hz the air speed is at an acceptable 30m/s. 

So, again, if WinISD is to be believed, I'm wondering if the same kind of design couldn't be applied to the Sicko to put together a monster sub.  Even if it requires a PR alignment in single driver configurations, would larger designs allow lower tuned ported options?  Maybe I'm totally out in left field here and just don't know it.  If that's the case, I'll just build a huge IB and not worry about it.  Just exploring the options here.

[Kevin Haskins]

Kevin,
I'm definitely looking to tune lower than that.  My design goal is a freq response that's reasonably flat to the 10hz region, combined with very high SQ and output (which I haven't quantified yet, but it will probably be about 130db at the listening position).  The SQ will be achieved by selecting a driver with a linear BL design like the LMS or Sicko, and not running it past the linear limits.  I'll use as many drivers, amps, and as large an enclosure as needed to achieve that.  The enclosure will be located behind the theater in its own room, so I've got virtually no size restrictions, even for silly numbers of drivers. 

I've done some modeling using the LMS-5400 which has bad issues with ported designs when modeling 1 driver enclosure sizes.  The port resonances are unworkable, leaving PR as the only option.  I'm guess the Sicko might have similar issues.  But it appears that once you start getting into REALLY large enclosures, ~100 cu ft, using multiple drivers (8, in this case) those issues fade as you get lower tuning with shorter ports.  At least if WinISD can be believed, anyway.  Because of that, I was able to create an EBS model using 8 LMS-5400 drivers in 100cu ft that looks quite workable.  When I scale this same model down to one driver (12.5 cu ft), the 1st port resonance comes in at an appalling 19hz, but with 8 drivers and 100cu ft, it's a very acceptable 218hz.  The only parameter that looks iffy in this model is the air speed through the port, but the highest speed (68 m/s) is way down at about 9hz.  However, there isn't a whole lot of signal that low, allowing leeway there.  At 14hz the air speed is at an acceptable 30m/s. 

So, again, if WinISD is to be believed, I'm wondering if the same kind of design couldn't be applied to the Sicko to put together a monster sub.  Even if it requires a PR alignment in single driver configurations, would larger designs allow lower tuned ported options?  Maybe I'm totally out in left field here and just don't know it.  If that's the case, I'll just build a huge IB and not worry about it.  Just exploring the options here.

You are borderline nuts davepete.        You are the perfect guy for the Sicko! 

Ports are not going to work.   They get too large, and have too many port resonance/airflow issues.    PRs will work, but have limits to how much mass you can put on them.    In the smaller sane sized enclosures, it becomes tough to load the PR with enough mass to tune much below the 15-16Hz range that I'm targeting for a 9-10ft^3 application.    If you double the box size, you will be able to go deeper.   I won't know exactly how deep until we build some PRs and see what they will take.   Even then, I tend to estimate on the conservative side so that I don't have customers ripping them apart.

For your application, which doesn't seem to have a budget, just run them sealed and use a bunch of them.    That gives you great low frequency extension and you can get as much output as you have space and money.

[klh]

For your application, which doesn't seem to have a budget, just run them sealed and use a bunch of them.    That gives you great low frequency extension and you can get as much output as you have space and money.

Kevin,

Since you think sealed is the better way to go, would you advocate using an LT circuit?



Davepete...

Why don't you get a bunch of these and do an IB (an ultra large sealed enclosure)? The install negates the need for enclosures within the room, decreases the demand for amplification, and then you get great low end excursion without the need for extra processing (LT circuit). I'm using two 18" drivers in an IB that pale in comparison to these beasts and I'm flat to 10 Hz... I don't get the SPL that you want (I'm getting about 115dB), but having 4 of these puppies would probably do the trick. 8 would be unreal. Just be sure to have a manifold so you're running opposed pairs so you reduce mechanical vibrations that would tear apart your walls !!!!!!!

[Kevin Haskins]

For your application, which doesn't seem to have a budget, just run them sealed and use a bunch of them.    That gives you great low frequency extension and you can get as much output as you have space and money.

Kevin,

Since you think sealed is the better way to go, would you advocate using an LT circuit?

It depends on what your goals are..... but I'd say sure.   There is no reason not to use some equalization with this kind of project.   It gives you box size flexibility and the choice of final system Q.   

[davepete]

You are borderline nuts davepete.        You are the perfect guy for the Sicko! 

The way I look at it, I'm looking for bass that will bring out the full experience that the creators of the movies intended.  Everyone else is nuts for settling for less than that.   

Ports are not going to work.   They get too large, and have too many port resonance/airflow issues.    PRs will work, but have limits to how much mass you can put on them.    In the smaller sane sized enclosures, it becomes tough to load the PR with enough mass to tune much below the 15-16Hz range that I'm targeting for a 9-10ft^3 application.    If you double the box size, you will be able to go deeper.   I won't know exactly how deep until we build some PRs and see what they will take.   Even then, I tend to estimate on the conservative side so that I don't have customers ripping them apart.

For your application, which doesn't seem to have a budget, just run them sealed and use a bunch of them.    That gives you great low frequency extension and you can get as much output as you have space and money.

I realize the ports would be large - my model calls for a 16" diameter pipe.  It would definitely need to be internally braced.  I agree on the PRs.  I consider them extra moving parts that I don't really need when a port will do essentially the same thing without moving/wear issues.  I haven't found anyone who has built a ported sub of the size I'm looking at, though, so I'm not sure if resonance issues would apply as the port lengths do get a lot shorter in really big enclosures.  In any case, I'll probably just build the IB, as that entails a lot fewer tweaky type details and would be much easier to construct.  I'll still have to consider whether to use a manifold or not.  With 21" drivers, a manifold isn't a small undertaking!

Thanks for the input, Kevin.  I'll be looking forward to the T/S specs when available.

[Russell Dawkins]

Hi Kevin,

Why the complex basket structure - would a cast basket not have been feasible?

[Kevin Haskins]

Hi Kevin,

Why the complex basket structure - would a cast basket not have been feasible?

Sure... it would cost $25,000 to tool.    This one has a higher cost per unit (about $80-$100) but lower tooling cost.   It is also scalable to be used for 15" & 18" drivers.    Tooling three baskets would be well over $50,000 in tooling.   For a product that sells 100/yr it isn't a good choice.   

[Russell Dawkins]

Thanks - a clever solution - especially the scaling potential.
I hadn't thought of that, but can see the 15 and the 18 in the basket for the 21, now that you mention it.

[cityjim]

 pardon the thread jack . This is surely a sick project no doubt .

 But please check this out . A true 22 inch monster with a 900 OZ. magnet    And a 6.5" voice coil setup

 http://www.mtx.com/caraudio/products/subwoofers/jackHammer.cfm


cityjim

[Kevin Haskins]

pardon the thread jack . This is surely a sick project no doubt .

 But please check this out . A true 22 inch monster with a 900 OZ. magnet    And a 6.5" voice coil setup

 http://www.mtx.com/caraudio/products/subwoofers/jackHammer.cfm


cityjim

It isn't usable..... notice they don't list parameters.    It is a competition sub for burps and that is pretty much all it's good for. 

I'm out to create a truly USABLE subwoofer with the inductance of a midrange driver, usable in sane sized enclosures that is as linear as anything ever made.   

That is the design goal... not a car audio competition product although I'm sure there will be a couple guys wanting to use it as such.

[klh]

Kevin... do you have an estimated cost for the end user?

I know you previously estimated the cost to be about $1000 for the active woofer, but since then you jumped from a standard 18" size to a much more custom 21" size. I would have to think your cost went up.

[Kevin Haskins]

Kevin... do you have an estimated cost for the end user?

I know you previously estimated the cost to be about $1000 for the active woofer, but since then you jumped from a standard 18" size to a much more custom 21" size. I would have to think your cost went up.

We started off as a $1000 price goal for a LMS-5400 replacement.   That was back when it was going to be a 4" VC with 38mm of x-max.    We have had some mission creep since then, basically expanding x-max to 55mm with the Parthenonn motor, jumped to a 5" VC, added a counter coil, and bumped the overall diameter up to 21".    The Parthenon type motor is Neo based and we are having to do a lot of machining to remove excess weight and keep the format usable.   

I'm estimating we are at $1500 now but I won't really know until we are closer to production.    I'm not really concerned with where the price lands, I just want to build the best subwoofer on the planet.   We have other products that are a better "value" type of products and I'm comfortable with our position there. 

A little later, we will develop a series of subs to fit between our current subs, and the Sicko.   I'll probably use the Sicko basket, cone, and suspension components and drop them onto a more traditional 4" VC motor with that original LMS-5400 type x-max of 38mm.    Those should occupy a price-point somewhere between Sicko-land and our value lineup since that Parthenon motor is extremely expensive to manufacture.    I'd like to see a 15" and an 18" in the midline series that fits in the $500-$800 range and offers some incredible performance in their own right.   
 

[klh]

Thanks for the update. I'm not surprised the least bit to see the jump in price. Ultimately, getting the best requires a premium price. Imagine what the price would be if Wilson got ahold of this puppy! I bet they'd charge at least $40k when you consider the fact that their dual 18" LLT was $20k several years back.

[cityjim]

pardon the thread jack . This is surely a sick project no doubt .

 But please check this out . A true 22 inch monster with a 900 OZ. magnet    And a 6.5" voice coil setup

 http://www.mtx.com/caraudio/products/subwoofers/jackHammer.cfm


cityjim

It isn't usable..... notice they don't list parameters.    It is a competition sub for burps and that is pretty much all it's good for. 

I'm out to create a truly USABLE subwoofer with the inductance of a midrange driver, usable in sane sized enclosures that is as linear as anything ever made.   

That is the design goal... not a car audio competition product although I'm sure there will be a couple guys wanting to use it as such.

 It was on MTV's "Pimp My Ride" and numerous videos on the net . Parameters are on page 2 . X-max 2.5 inches and X-mech of 3 inches , OMG .   http://www.thetrue22.com/downloads/JackHammer%20Owners%20manual.pdf   

 Sealed enclosure of 4.2 cubic feet and vented 8.7 cubic feet .  I personally like the comment made by MTX for the installation of this 22 incher . MTX mentions "forklift" . 

 Here is one of the videos . http://www.youtube.com/watch?v=BvXY-Cgpz68


cityjim

[cityjim]

http://www.youtube.com/watch?v=2ecC5LOabPY&feature=related


cityjim

[Kevin Haskins]

Out of curiosity, how much does it cost?

[BradJudy]

Out of curiosity, how much does it cost?

$7000 - http://www.woofersetc.com/index.cfm?fuseaction=product.display&Product_ID=3344

[Kevin Haskins]

Not at all surprising....    I love the look on that guy's face when he looks in the back.   

The Sicko isn't going to have the same shock value as we have trimmed the motor weight down to around 85lbs.    They should have us slightly edged out on the mechanical clearance but I'd bet money we have more linear stroke.   Are those numbers one-way or two-way?   The inductance on that thing has to be pretty ugly too and I'm also fairly certain we will have greater Sd, even though they are calling it a 22".    That refers to the frame, not the driver's swept area.   

In terms of usable parameters.... I'd like to see what someone measured for the T/S parameters.   Surely someone has measured one.     

[davepete]

You don't need T/S parameters to get one-note bass...   

[Kevin Haskins]

You don't need T/S parameters to get one-note bass...   

Car audio is all about power handling where they want to run MASSIVE amounts of power into the device for short burst in SPL competitions.    The large coil is a benefit, as it increases short-term power handling.   The inductance of these long massive coils though is extremely problematic in real use.   Not only does it limit high frequency extension, Le based flux modulation can cause eddy currents in the motor itself and the larger the coil inductance, the higher the power, the bigger the problem.    We get around it with active Le cancellation via the counter coil.   They probably are using some sort of shorting ring to at least keep it manageable at lower power.   

I'd like to see the parameters though so I can model their recommended boxes.   I'm just curious.