Yes I would be interested in this project too.
darrenv1070 said Paul, for 15k a pair! Count me in on a pair. When can I pre order.
Paul said
Maybe I’ll post this separately and get some comments. It’s not like the speaker market’s crowded or anything…
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Would optionally active crossovers be possible ? Would sell more BHKs...
GM wrote:
Heard a demo of the Gryphon Pendragon a month or two ago. Most beautiful thing I’ve ever heard. The full system runs about AU$350k here, so I was told.
Putting into anything approaching the quality of the Gryphon Pendragon for US$15k - is that a remotely crowded part of the market ?
How many years away might these beauties be ?
Oh, we’re easily a year away from anything.
Only one, that’s pretty close.
I’ll keep my Salon2’s and wait.
Paul McGowan said Oh, we're easily a year away from anything.Is that a calendar year or a "Paul's" year?
Very exciting project. I’d definitely be interested. I like the idea of the side firing woofers. My older speakers (NHT 3.3) used that concept to great success.
Seeing that I have so much else PS Audio gear (still waiting for shipment of my Beta Pre-amp Unit) I’ll be happy to put my name on the list to test out these speakers in an all PS Audio system (other than my turntable). 
Paul
Do you expect these speakers would still benefit from a Sub Woofer in a 2 channel system or would the 10" powered woofers make this not so necessary?
magicknow
Streets Still Works saidPaul McGowan said Oh, we're easily a year away from anything.Is that a calendar year or a “Paul’s” year?
As we understand the two are different, let’s go with Paul Year.
Paul McGowan said I will keep you updated though, as you can imagine, there's a ton of work to go . . .Paul, what is your thoughts on aluminum vs HDF? Maybe even an internal coating to cut down on resonance. Not sure if that would fly, but my Def Tech Mythos ST-L 's are aluminum. They work very well for the cost of them.
I am not a speaker designer so maybe I just swore at you. LOL.
Paul McGowan said
snip...
Rythmik uses a patented DirectServo mechanism for their Servo Subs that does not use an accelerometer. From their website
- Start specifying the drivers. In this case, we've been working on the 10" subwoofer part, calling out for an XMAX we're happy with, the types of motor, material, frame construction, spider, accelerometer etc. Then there's the other two: the tweeter and the midbass couplers, each Arnie has detailed a long list of demands.
How is Direct Servo different to other servo subwoofers?
Our philosophy is to make audio products as simple as they can be. Less is more. Our subwoofers put as little into the signal path as possible. This approach applies to our amplifiers, Direct Servo technology and drivers. Most servo subwoofers use an accelerometer, which is another mechanical system with its own limitations. Also extensive protection circuits are required, and these further degrade the signal. As a result, accelerometer based servos are not as accurate as Direct Servo. The superiority of Direct Servo is derived from its simplicity.
Direct Servo uses a very thin sensing coil which is wound adjacent to the voice coil. The coil acts as a custom made microphone which creates a signal which is then used to correct any difference from the original signal. Any non linearities are instantly corrected.
They have 8", 12" and 15" drivers (no 10"), but it might be worth contacting them to see if you could license their technology and if you could have a 10" driver built to your specs, as long as you are starting from scratch.
Here is a link that illustrates their DirectServo system.
magicknow said PaulDo you expect these speakers would still benefit from a Sub Woofer in a 2 channel system or would the 10" powered woofers make this not so necessary?
magicknow
I would guess they will not need an added subwoofer - and if they do, then we didn’t do a good enough job. 4 10" servo controlled subs should be able to go down quite low, perhaps full to 20Hz before being rolled off. Now, some will want even lower and I would never argue with them, but when I install them, wherever they’re going to go, they should need nothing else but some great electronics to power them.
These will not replace the IRSV in Music Room One as some have speculated. I haven’t yet figured out how or where they’ll go - possibly my living room if Terri allows - or we may build a second Music Room if we can clear out some space.
darrenv1070 saidPaul McGowan said I will keep you updated though, as you can imagine, there's a ton of work to go . . .Paul, what is your thoughts on aluminum vs HDF? Maybe even an internal coating to cut down on resonance. Not sure if that would fly, but my Def Tech Mythos ST-L 's are aluminum. They work very well for the cost of them.
I am not a speaker designer so maybe I just swore at you. LOL.
Not at all. Aluminum is fine and more rigid than HDF. But your Def Techs are relatively small compared to these beasts. As it is, these will likely weigh over 100 pounds each and if they were out of aluminum significantly more - and the cost would be astronomical - way out of where we want to be.
Our goal is to produce a full range world class loudspeaker, voiced by Arnie (he makes speakers disappear), that people can afford. Others, like Magico and YG become unaffordable to most people - not a place we want to be.
Design’s all about making smart choices. If I thought performance would be compromised in any noticeable manner, I’d go with aluminum and just take our lumps. I doubt few people would hear any difference between a properly designed HDF cabinet and an aluminum version. Yet the difference in cost would be dramatic.
I am very familiar with this method and do not approve of it. While it does use motional feedback, it is not a true servo because it cannot measure the actual position of the woofer, relative to the input signal to the amplifier.
What they are doing is simply adding a second coil onto the woofer bobbin and using that as a sensing circuit. When the speaker’s in motion, the output signal does give the designer some measure of feedback that can be used to correct for distortion - and it’s certainly better than having nothing at all.
An accelerometer, on the other hand, is a true servo that measures position, velocity and is the perfect sensing mechanism for a woofer. The problem with accelerometers for many manufacturers is several fold: they’d hard to assemble, they are difficult to control and design, and most speaker designers don’t have the electronic chops to make them work.
Thanks for the education on the two servo mechanisms.
Yes, it’s a tough subject and one not often written about.
True motional feedback requires a position sensor attached to the cone itself and the easiest way to do that is with an accelerometer. I have seen other schemes using a mirror and a light beam/sensor and that works well too, but terribly difficult to get it right and there’s all the mechanical issues to boot.
Accelerometers used to be expensive. The ones used on my Infinity IRSV woofers ran the company $350 each and they were aerospace rejects at that! Today, we can use a piezo electric disc that runs about a $1 and through clever engineering, get exacting location information from the woofer - and lower distortion by a factor of 10, perfect FR in a sealed box.
Though another thing to remember when designing true servo systems; the power requirements. True flat frequency response in a sealed box means the designer requires 4X power for every octave below box resonance. This means to get down to 20Hz in a small sealed box, you need a buttload of power. We’re targeting 700 to 800 watts to start out with.
Paul McGowan said . . . you need a buttload of power.I enjoy learning esoteric specialized terminology.
Butt
A unit of momentum referencing that which is required to overcome Coulomb forces in the nucleus of an atom so that the nuclear forces can dominate resulting in nuclear fusion and ejection of a particle or photon. The namesake of Dr. Otto Buttenholerhoff, whose 1897 discovery insured that he would remain the butt of jokes for eternity.
Paul McGowan said Yes, it's a tough subject and one not often written about.True motional feedback requires a position sensor attached to the cone itself and the easiest way to do that is with an accelerometer. I have seen other schemes using a mirror and a light beam/sensor and that works well too, but terribly difficult to get it right and there’s all the mechanical issues to boot.
Accelerometers used to be expensive. The ones used on my Infinity IRSV woofers ran the company $350 each and they were aerospace rejects at that! Today, we can use a piezo electric disc that runs about a $1 and through clever engineering, get exacting location information from the woofer - and lower distortion by a factor of 10, perfect FR in a sealed box.
Though another thing to remember when designing true servo systems; the power requirements. True flat frequency response in a sealed box means the designer requires 4X power for every octave below box resonance. This means to get down to 20Hz in a small sealed box, you need a buttload of power. We’re targeting 700 to 800 watts to start out with.
Back in 1973 when I started in the computer industry I used to watch the heads of the disc drives (30mb, the size of a fridge, albeit a British fridge rather than an American one) and reckoned it could be developed into a great speaker system. The DEC disc drives used a grating to work out where the head was. Our one had a slight crack in it and about once a day we’d get read errors.
Paul McGowan saidStreets Still Works saidPaul McGowan said Oh, we're easily a year away from anything.Is that a calendar year or a “Paul’s” year?
As we understand the two are different, let’s go with Paul Year.
Hmm, is that a “Paul’s” year with or without an Arnie/Bascom correction factor? (Even those two may have separate and distinct time constant modifiers . . . .)
–SSW
I see a variant of E=mc2 emerging here… 