.

Wayne and curegeorg,

Yamaha uses servo control on many (if not all) of its subs.

I've used a Yamaha YST-SW/80 in my dining room in a three piece stereo configuration for years.

Within its design limits, and at all reasonable listening levels, its a great little inexpensive sub - as are others in the current product line.

I don't expect it to compete with my Velodynes or B&W subs, nor should I.

Jeff Mackwood

wayne im sure you forgot some companies that use m&k...

------------------

This post has been brought to you by curegeorg, thanks for reading.

.

I don't think you'll be taking that thing anywhere without a forklift.

I recently finished a sub that some might find interesting:

2- Tumults

Opposite-firing, push/push, to reduce cabinet vibration.

Custom hourglass cylinder, 1/2" thick PVC shell.

1 1/4" thick solid, custom CNC machined Mic 6 aluminum baffles.

On board L/T circuit to flatten and extend frequency response.

Only 2 1/2 cubic feet net interior volume.

One 1,050 Watts into 2 ohms switching amplifier PER VOICE COIL (4,200 Watts total)

Adjustable system 'Q', from .45 to 1.2.

Variable phase, 12 position, in 15 degree increments, plus a 0/180 switch.

Gain, phase and Q controls on the front panel. RCA/XLR inputs and detachable power cord on the back panel.

Signal/clip/protect indicator LEDs.

Lighted front panel control knobs to indicate position from across the room, at a glance.

I've built 17 subs in the past 9 or so months and used 22 drivers from around the world. The Adire XBL2 motor, which is basically a multi-gap, underhung (Dan Wiggins told me he prefers 'inner hung') design, is definitely for real.

BTW, this is a dedicated, discrete LFE only sub. I have a similar 2X15, using custom made drivers for dedicated redirected bass that's optimized for integration with my sats, but it's only powered by 4-800 Watt amps.

Alrighty Bosso... so now the question is how many blocks away do you have to get before you stop feeling the bass from your subs?

...my mother in law thought an earthquake was starting from just my one Tumult..

Bosso, you got any pics? What kind of frequency response does that mad thing put out?

Last week, my neighbor across the street lost electrical power. He told me that he was headed over to my house to see if I had lost power also.

He said that he got 1/2 way down his driveway and felt the rumble, so he knew I hadn't lost power, turned around and went back home.

I was testing the system, playing chapter 9 from LOTR FOTR (the on-fire, big demon dude) at that particular moment, clocking 127 dB peaks from 12 feet in 3,200 cubic feet, no clipping, no bottoming.

That sort of thing is fun, once in a while, but I really designed the system for max flexibility and sound quality. I mostly listen to hi-rez MC audio at around 90 dB with 105ish dB peaks.

Since there are 3 proprietary features that are still under non-disclosure agreement and that would be instantly seen in pics, I can't post any...yet. I promise pics soon, 'cause you just gotta see these.

To answer the original question of this thread, I look for effortless, on-time, distortion-free low freq reproduction with PLENTY of headroom in a small footprint, extraordinary industrial design package.

Impossible to find in the current commercial offerings, so I designed and built my own.

It's been a BLAST...literally.

What would one of these beasts cost a person interested in having one built?(Assuming all the engineering hours are complete, the costs would go for labor & materials - I'll assume the CNC program is saved on a disc which could simply be reloaded and run?)