SICKO-18" Project

Kevin Haskins · « **on:** 12 Feb 2008, 02:48 am »

Ok... this thread started over at AVS while talking about designing a cost is no object 18" driver.

I'll update this thread as we go through the design process.

Design Goal: The highest output, lowest distortion subwoofer we can build in 7-10 cubic feet, powered by a Face Audio F1200-TS.

More to come...

Larry McConville · « **Reply #1 on:** 12 Feb 2008, 03:09 am »

Outstanding; should be a fun journey!

Kevin Haskins · « **Reply #2 on:** 12 Feb 2008, 03:30 pm »

Details of Concept:

Box Size: 7-12 ft^3

System Design: Single 18" driver with dual matching 18" Passive Radiators.

Power: Face Audio F1200-TS 4700W of power into the driver

Goal: The most accurate and powerful sub on the planet, that can fit in the defined box size, powered by a single 15A/20A breaker. Output >115dB @ 10Hz in-room measured from 1M, >120dB from 14Hz on up, measured from 1M. Anechoic F3 about 20Hz (depending upon signal processing settings) and >116dB anechoic from 25Hz up.

Transducer Design:

*5" Voice Coil with split gap, split coil motor design. Power handling out the ying-yang and at least 55mm of X-max. 70mm of X-mech so we have a full 5.5" of mechanical clearance and 4.3" of clean stroke peak-peak.

*Counter Coil to virtually eliminate inductance issues, careful design for symmetric Le curve for the inductance we have. Counter coils won't saturate with power like shorting rings. End result, 5" VC with very little inductance and EXTREMELY linear with power, frequency and stroke. Impedance curve looks like a planar, ruler flat way out beyond what you typically see with a sub.

*Specially tooled 14" spider with some unique mojo to linearize Cms and maintain production tolerances within +/-5%. Designed to fully support full capabilities of the motor.

*Specially tooled Surround with symmetric Cms curve, both inner & outer rolls like a progressive spider fully supporting the full capabilities of the motor.

*T/S Parameters close to our Maelstrom-X. Parameters usable in both PR/sealed systems of large but manageable size.

*Matching Passive Radiators with the same 5.5" of peak-peak throw.

*Projected Price for the driver: $1000 each Projected Price for the Passive Radiators: $250ea (two needed)

*Projected Price for complete projects (driver, PRs, amp & signal processing): $2500

*Projected Availability: November 2008

Steven Kephart · « **Reply #3 on:** 13 Feb 2008, 07:41 am »

Are you doing a split coil for price reasons? Why not just do 3-4 gaps for a single coil to transverse? That should reduce Mms (if needed) and reduce inductance. I definitely can't wait to see this monster develop.

Kevin Haskins · « **Reply #4 on:** 13 Feb 2008, 05:38 pm »

Quote from: Steven Kephart on 13 Feb 2008, 07:41 am

Are you doing a split coil for price reasons? Why not just do 3-4 gaps for a single coil to transverse? That should reduce Mms (if needed) and reduce inductance. I definitely can't wait to see this monster develop.

Dan is making that choice. Reducing inductance won't be an issue due to the counter coil and I won't know if we need to add or reduce mass until we get a little further along.

This will be a fun project.

klh · « **Reply #5 on:** 13 Feb 2008, 09:45 pm »

aa

mcgsxr · « **Reply #6 on:** 13 Feb 2008, 11:10 pm »

That does sound like a lot of fun!

About 5 years ago I built an HT sub for myself, with a car Nakamichi sub. Built a ported box, 23Hz tuning, and 4 cubic feet.

Not going to suggest that it came ANYWHERE close to the clean, clear, sub bass that you will get with this monster, just chiming in that boxes for pure HT bass can be a lot of fun!

Good luck with it,

JohnR · « **Reply #7 on:** 14 Feb 2008, 09:33 am »

Quote from: Kevin Haskins on 12 Feb 2008, 03:30 pm

Power: Face Audio F1200-TS 4700W of power into the driver

Goal: The most accurate and powerful sub on the planet, that can fit in the defined box size, powered by a single 15A/20A breaker.

Just curious - how do you get 4700W through a 15A/20A breaker?

Kevin Haskins · « **Reply #8 on:** 14 Feb 2008, 04:38 pm »

Quote from: JohnR on 14 Feb 2008, 09:33 am

Quote from: Kevin Haskins on 12 Feb 2008, 03:30 pm
Power: Face Audio F1200-TS 4700W of power into the driver

Goal: The most accurate and powerful sub on the planet, that can fit in the defined box size, powered by a single 15A/20A breaker.

Just curious - how do you get 4700W through a 15A/20A breaker?

You don't continuous. That is a worst case (or best case depending on your point of view) situation. The transducers won't be a perfectly resistive 2-Ohm load, it will vary at low frequencies due to the impedance peak at resonance so in real-life, you never get those "perfect" conditions to deliver full power. The counter-coil would provide an almost perfectly flat impedance curve, even at resonance, but we will add a capacitor in series returning it to what looks like a normal impedance curve down low. Otherwise you loose about 3dB of sensitivity in the pass band.

If it where a perfectly resistive load, you might be able to get a peak power rating close to that. Amps are able to deliver peaks much higher than RMS rating due to the power supplies reserves. Line voltage & sag vary, changing output power, so there are several variables to consider.

If we design for roughly 5KW though we make sure the driver is never the limiting factor. Since music/movies is about a 30% duty cycle, the peak power ratings are appropriate to design around. If you have peaks @ 1000W you need approx the ability to provide 300W continuous. Or, if your peak power is 5KW, your continuous should be around 1500W.

Kevin Haskins · « **Reply #9 on:** 19 Feb 2008, 02:13 pm »

Motor design for lots of linear BL.

This is +/- 1% out to 42mm.... ONE WAY!

X-max is about 55-56mm one-way!

For a frame of reference, the TC Sounds LMS-5400 was listed as having +/- 1% linear BL out to 30mm, and X-max at 38mm one-way. That gives us a full extra inch of linear (+/- 1% BL) peak-peak throw.

Larry McConville · « **Reply #10 on:** 19 Feb 2008, 06:46 pm »

Well, that proves it; this thread is appropriately named. That's just 'Sick'!

gprro · « **Reply #11 on:** 22 Feb 2008, 09:02 pm »

Thats shocking...1% at 42mm!!! That's got to be pushing the limits of linear xmax possible. I want four

Larry McConville · « **Reply #12 on:** 22 Feb 2008, 10:29 pm »

No doubt; really exciting stuff here. I will have a pair of Maelstrom X's driven by a Face Audio 1200; I have no idea what I'll do with a pair of these 'Sick' 18's; although, I'm sure I'll find something

Quote from: gprro on 22 Feb 2008, 09:02 pm

Thats shocking...1% at 42mm!!! That's got to be pushing the limits of linear xmax possible. I want four

vactor · « **Reply #13 on:** 27 Feb 2008, 06:06 pm »

amazing stuff.

Larry McConville · « **Reply #14 on:** 27 Feb 2008, 06:19 pm »

Afternoon Kevin,

I'll be shooting you an email shortly; I'd like to pick up a second Face F1200...

Kevin Haskins · « **Reply #15 on:** 27 Feb 2008, 07:53 pm »

No problem Larry.

The Sicko is moving forward. I'm pushing on this hard with hopes of beating our deadline.

You won't have to worry about bottoming this bad boy. In free-air it takes 5000W to bottom it.

Put it in a box and its probably going to take 10,000W or more to hit the back plate.

You guys wanted an extreme driver, we are going to deliver.

Larry McConville · « **Reply #16 on:** 27 Feb 2008, 08:10 pm »

Hence the second F1200…

Quote from: Kevin Haskins on 27 Feb 2008, 07:53 pm

No problem Larry.

The Sicko is moving forward. I'm pushing on this hard with hopes of beating our deadline.

You won't have to worry about bottoming this bad boy. In free-air it takes 5000W to bottom it. Put it in a box and its probably going to take 10,000W or more to hit the back plate.

You guys wanted an extreme driver, we are going to deliver.

Kevin Haskins · « **Reply #17 on:** 7 Mar 2008, 07:48 pm »

Ok.... this is appropriately named. The motor is about 12.5" in diameter, 6.5" deep so the motor alone is the size of a Shiva-X.

We are working on trimming some weight because we are up around 100lbs for the motor alone, WITH NEO!

This is looking at the top plate. Nice big 5" Voice Coil provides a pole vent big enough for small animals to climb into. Your going to have to watch the cat because he/she doesn't want to be in there when you fire it up.

Cut-away of the pole, back plate & front plate (not cut-away).

This will represent a high-water mark in the subwoofer market. The Sicko will be within its 1% linear BL range under almost all conditions with the F1200-TS. It will also be well within its suspension linearity and the inductance will be amazingly controlled. In other words, it should be the most linear subwoofer ever made by a long shot.

As you can see from the renderings, the power handling is going to be helped with the open motor design, not to mention the 5" VC so you have voice coil cooling unlike anything on the market.

For you open baffle guys, the motor will be EXTREMELY low-noise. Not only will the motor design be open, the spider landing is going to be equal distance from the top plate as the cone is from the spider landing. This is the kind of driver that will provide THX levels of output at 20Hz on a 3' wide open baffle!

klh · « **Reply #18 on:** 7 Mar 2008, 08:14 pm »

Imagine supporting a 100+ lbs speaker with 40-50mm controlled one way excursion with an open baffle

. The baffle itself is going to need a heroic design!

Kevin Haskins · « **Reply #19 on:** 7 Mar 2008, 08:18 pm »

Quote from: klh on 7 Mar 2008, 08:14 pm

Imagine supporting a 100+ lbs speaker with 40-50mm controlled one way excursion with an open baffle . The baffle itself is going to need a heroic design!

Hey... that is their problem. If they have the money for a pair of these beasties they can make it out of granite. I have a granite counter top place next door to my industrial site. That stuff is $125/ft^2 so my subs are cheap in comparison. They have a nice big CNC machine cutting the marble tops. You need a fork truck to move the damn things but it would work.