Heres the link for the Accupulse.
http://users.skynet.be/accupulse/
Satyam. |
Sbfx -- the diy you present reminds me of the those Audio Physic Medea I had many years ago.
The diyer probably achieved better implementation I assume... |
Not having heard the MANGERS yet, I only wanted to interject an observation I've made relating to pistonic diaphragms in general. The conventional dynamic loudspeaker has a diaphragm that is supposed to be perfectly rigid. As this is not actually possible with known materials, some distortions are inevitable. They take the form of bending waves and nodes like the choppy waves on the surface of a swimming pool after a person does a cannon ball into it.
I believe it can be demonstrated with laser interferometry experiments that a SLOW amplifier, one that has POOR DAMPING and TRUNCATED high frequency response, will excite these modes less in a poorly designed piston-type radiator. A voice coil attached to a narrow band of material on any "cone" or other common geometry not only has to accelerate the diaphragm, but also must yank it to a halt when the sound stimulus is supposed to be decaying/ending. With a power amplifier that has a high degree of control over the motor system, the equivalent is like a MAC truck hauling a trailer hitting a concrete bridge abutment. The area of the cab will stop in a hurry, but the rest of the vehicle will do a lot of moving before it’s over. A Fostex white paper discusses rate of propagation in materials being related to internal damping possibilities in a diaphragm, and its an interesting intersection that sapphire and diamond diaphragms are at the same time stiff and high-velocity with respect to internal sound propagation. If a given amount of damping is provided by added materials like the surround, voice coil interface, and the air load, the TIME period for the decay of undesired energy from the diaphragm is shortened, thus adding to “clarity”. This does not equate with total energy, but that may not have as much bearing on psycho-acoustic perception. Such diaphragms are likely resistant to the charms of weak amplifier coupling, as they don’t “benefit” from it.
I have a great deal of respect for Mr. Pass, and watched with some appreciation his arc of experience with this issue. I am bemused by the appearance of his missing this "link" as to why a "poor" amplifier might actually sound better. Driving speakers with diaphragm designs that "freak out" when presented with an iron grip on their voice coils by a high damping factor, high rise-time, wide band solid state amplifier using high local and global negative feedback to get there may be part of the explanation. I think the "distortions" are not the vanishingly low harmonic fuzz you get from imperfect group delay in feedback servo loops, but instead the complaints of diaphragms abused by their own voice coils. A tube amp may have an output impedance EQUAL to the voice coil impedance, for a damping factor of ONE. Try this experiment some time; lightly tap on the woofer cone of a speaker with no wires connected. Then do it with a 4-8 ohm resistor across the input. Then, short the input together on the speaker terminals, and tap again. Each report from your test bell will sound different, and your finger tapping sound is EXACTLY like the decay the speaker adds right after being stimulated by musical impulses. The smooth relaxed sound so many tube and SET aficionados care for may be the avoidance of stimulating break-up modes in conventional dynamic speakers. These distortions, unlike simple harmonics, are non-mathematically correlated, and occur in time AFTER the musical signal, rather than with it. Reducing them may indeed be a technical justification for seemingly reduced performance systems sounding better, in some combinations. Conversely, solving the dynamic speaker design problem by reducing these modes in a diaphragm deliberately may allow us to move away from pretty glowing tubes, and their other limitations.
All this leads up to the Manger. Instead of pretending it is a rigid piston like dynamic drivers to, it is a thin flappy membrane carefully tuned to produce MAXIMUM POSSIBLE NODES of bending from the voice coil motion. One can think of it as the worst pistonic speaker design ever, with near-zero rigidity. As such, it need not suffer from bending modes as distortion; it is the OPERATING PRINCIPLE instead, on purpose! Like the pretty ripples in a circular pool of water when a pebble is dropped exactly in the center, it is like a cross section of pressure/rarefaction in a spherical acoustical volume around a point source radiator. Up to a certain frequency defined by the voice coil diameter and material tension, it should be hemispherically radiating irrespective of its membrane diameter. The point is, the OPPOSITE effects of damping and bandwidth from an amplifier apply in the case of the Manger. A poor damping factor will make the amp unable to fully modulate the center of the "pool" of the manger, and thus not introduce the correct counter action to the high amplitude of modulation of the diaphragm, on the DECAY of musical signals. Think of an SUV with 4-wheel drive on ice; much easier to get going than to stop. The primary damping of the Manger is the air load it plays into, besides the voice coil and periphery materials. If you have a lackadaisical amp that used to go easy on floppy cone speakers, it will have no chance to get anything meaningful out of the Manger.
I applaud Mr. Pass for doing the practical footwork that bolsters my theory. I plan to do a physical demonstrator setup with a pair of Mangers and a variable damping factor apparatus, along with a representative pistonic system alongside. By introducing several series impedances in sequence, it should be possible to DEGRADE the apparent quality of sound from a Manger, and in some ways IMPROVE it from the pistonic. |
Finally;
MartinsV;
Where do people like you hang out?! because it is refreshing to see such insight and understanding, that I must admit that I share, well actually harbor your thoughts.
Its always risky to be so certain, but for all the negativity it will bring you; I couldn't agree more with your comments. |
These distortions, unlike simple harmonics, are non-mathematically correlated, and occur in time AFTER the musical signal Quite so. However, and apparently, these can be modelled -- but only with reference to electromechanical properties in each specific application. Unfortunately, I can't find a ref you may be interested in. BTW, a simple experiment with very hard cone material coupled to powerful electromagnetic support, may reveal an "overdamping" effect (i.e. relative spl drops faster than projected -- further i.e., what we call "decay" is truncated, becoming "sub-audible" if I may coin the ugly word). A very interesting viewpoint, Martin. |
OK, This is an update on my MANGER adventures.
I've put my money where my mouth is. It will take a number of weeks for me to actually get my hands on the pair I found, but the ball is rolling. I'll post specifics of the construction of test boxes, and choice of vintage piston drivers that may be a good demonstration of "bad cones". Then will follow details on the testing protocol for waveform fidelity. I plan to use an arbitrary waveform generator making music-like percussive impulses. Departures from ideal decay profiles as provided by the generator will be considered distortion that is added by the driver based on available damping factor, modified with series impedance added inline with the drivers. I may try to use several "full range" drivers to avoid loading effects of passive filter networks. Later, I will use this same setup to test for gamma (Bl/Mms(d))requirements in subwoofer drivers.
Stay tuned! |
I hope you test on open baffle and measure below or at 30ms.
Of course, without interpolating passive components. Since you're using a generator, limit the bandwidth if necessary. |
What a gorgeous thread to join for I´ve been playing my Manger 103 Zerobox for many years now driven by tube amps.
My ears feel content so far, let´s wait and see what the instruments at the svoboda labs will find out. |
I have been playing the manger drivers in a pair of Medea's, they need time to break in, took over a ytwo years, and theyy also need fast amps, as well as powerful one's, they are reasonably efficient, but seem to really thrive on power. |
The Audio Physic Medea speakers were at the heart of the single most awesome moment I've ever had in the high-end hobby.
I was privileged to hear them at Immedia in Berkeley some seven years ago. They were utterly compelling, "hors classe" in a way that I've never heard a cone-driver speaker (or horn, or planar, etc.) even approximate.
The system backing the speakers, ohhh let me think - monoblock amps by SiriuS, the company that is now GamuT. The preamp was a Connoisseur Definitions v2, and LPs were spun on an Immedia "Revolution" turntable, of which too few were made. I was on the list for one such before I experienced a cash-flow discontinuity....
Wonderful speakers. Beyond my means then and now. But they are ranked among the very few products, audio or otherwise, that I wish I'd made the extra effort to know better.
Much like that girl who I really should have kissed when I was seventeen.
More wine, waiter!
cheers apo |
Hi all,
Please allow me to introduce myself. My name is Derek Wilson and it is with great trepidation that I enter your audio lions den!
For I bring some bad news for all fans of cone, dome, ribbon, panel (all things pistonic) and of course the evil passive crossover!
I do hope you will remain open minded after taking the time to read all the science, biology and technology that is detailed on the new Overkill Audio website.
I don't think I can print the link here but in the end there can be only one!
Our Finale, Encore, Predator, Prey, Angel and Dark Angel speaker systems along with The Conductor & The End Game should be easy to find and hopefully very difficult to ignore!.
As pretenders to the throne we must earn or shot at the title and we hope that the last 6 years of R&D and the fruits of our labour (again please see Overkillaudio website) will prove that we are indeed serious contenders. I do hope we will be allowed to organise some demonstrations and properly controlled independent audio shootouts in America. The first of the European shootouts will begin in the early spring 2008. For the lucky few music lovers who can afford $30 to $60K there is now a solution to all the audio reproduction problems.
I believe a year from now the Emperor is going to look very naked!
I thank you all for your time in advance of your replies (Gulp!) and as the great Winston Churchill once said " Whilst I totally disagree with you 100% I will defend until my dying breath your right to disagree with me"
Long live democracy!
Yours Sincerely
Derek Wilson
Overkill Audio
|
Derek,
I think they nuked the other recent thread. I expect you intended to post the information on this thread instead.
In any case I read about the Manger driver and am curious how it controls dispersion. To me it behaves like a ring radiator and therefore it will have a very narrow and extremely bumpy off axis dispersion pattern - at least without a phase plug...why no phase plug? |
Hi Shadorne,
Good question! There is actally a Manger phase plug, they call it a "hollow profile" and you can read about it on the Manger site. I have tried it and I dont like it. It's a big flat piece of clear plastic that covers half(!) of the driver. Basically the Manger produces too much signal if that makes any sense. The way the bending wave generates sound means that it produces two of everything and in theory covering half the driver improves imaging.
But its ugly and my Prey units dispersion pattern is almost perfect.
The bottom line is with my Prey head units you have a superb but narrow "perfect" sweet spot and everywhere else in the room gets a very natural but not pin sharp , musical sound.
I hope this helps!
Cheers
Derek. |
Dear Derek,
I must congratulate you on the progress you have made with the product line over the past 2-3 years. There was a point, when I really feared that the unforgiving commercial audio mafia would not allow a shinning light like Overkill Audio to survive, as it has happened to many great products in the past. Once again my best wishes are with you for the success of your brave venture.
Sphere. |
Thanks Sphere!
It's very encouraging to get a positive comment rather than the usual " if its not what I have its no good" response that I usually get when I post the ocasional article on Audiogon.
I am going to have another go at posting my "Eardrums & loudspeakers" article tomorrow ( they removed the old one when the cone and dome guys complained, they thought I might make a sale!) after I edit out all the Overkill Audio name and product names and sales pitch stuff. I have posted it on another forum and its great fun to watch the feathers fly!
All the best and thanks again for your kind words.
Cheers
Derek. |
Overkillaudio, I was one of those that objected to your previous thread, and while I currently use cones and domes, that had nothing to do with my objection. This forums integrity could be compromised if blatant advertising such as yours was permited. If you can find your way to market your products appropriately, I wish you the best of luck. |
Please... enough blatant advertising. |
Hello Unsound,
You are right of course & I apologise for being lazy & just cutting and pasting a chunk off my website and posting it here.
If everyone did this it would be a giant advertising hording and not a forum!
I am in the middle of editing out all refrences to my website & products and I am removing all sales pitch material. I hope this "white paper" approach will stimulate some good old debate! |
Eardrums, speakers, rights & wrongs.EDITED VERSION!
"Unique" has almost become a tired old cliché in the world of high end AV. Every man and his passive crossover are claiming "unique this" and "unique that". The sad truth is that 99.9999 (yes six nines!) of all the loudspeakers in the world are all using exactly the same, fatally flawed, 100 year old technology that does not work! Pistonic motion (cones, domes, ribbons and panels, yes including Quads!) and passive crossovers (inductors, capacitors and resistors) were first used in audio in the early 1900's! They didn’t work then and they still don’t work today, here are the two reasons why.
Timing, Timing and Timing & Speed, Speed and Speed . Please be patient, read on and allow me to explain this radical but true statement. OK, hold on to your preconceptions cause this is really going to put the hungry cat among the fat pigeons!
Timing first;
The human (and all the other land based mammals) ear does not care what a sound is, what a sound sounds like or if a sound is pleasant or unpleasant. All that matters is where a sound is coming from in three dimensional space. All mammals ear brain mechanisms were developed to locate prey or flee from predators. In mammals the primary trigger for the fight or flight response is aural. When our primate ancestors detected a noise they instantly bolted in the opposite direction, away from the source of the noise. They may have been 10 meters into their flight response before they correctly identified the sound and realised it was as a false alarm… like a falling coconut. Or they may have identified a snapping twig as a predator was about to strike, then they looked back and thought that was close!
Natural selection ensured the survival of the creatures with the most accurate spacial location hearing mechanism not the most accurate tonal identification mechanism. So how does this well documented and accepted science & biology affect you and me in today's audio world?
To answer that we must first take a brief look at the mechanics of our ears and how they work, how they don't work and how fast they work.
Fact, our ears do not use pistonic motion!
Our ears use a rippling (or bending wave) principle to decode sounds. The outer ear channels sound waves (a series of compression and rarefactions in the air) down the ear canal onto the centre of the ear drum (imagine dropping a small pebble into the centre of a calm pool of water) which then ripples in response to this sound energy hitting its centre. Various tissues & tiny hairs and nerves located all around the edges of the ear drum (imagine how a spider uses its legs to detect the movement of struggling prey in its web) convert this movement, Kinetic energy, into electrical energy, and these impulses are then sent to the brain for decoding.
Now speed.
The ear drums response time is critical. How quickly the ear drum starts and stops the rippling motion determines the accuracy and effectiveness of our ears. Mother nature addressed this mechanical limitation by evolving the fastest possible energy conversion system, the rippling or bending wave ear drum motion. Pistonic motion is far too slow. The reason the ear drum does not work like a cone loudspeaker driver (a mass on the end of a spring) is because it would be in constant oscillation as it wobbles in and out never having enough time to settle back to its neutral or starting point. This would send a constant stream of "ghost echoes" to our brains which would be impossible to decode quickly and accurately.
Our ears are incredibly sensitive and specialised devices which are designed to detect where sounds are located (spacial information) in a fraction of the time it takes to identify what a sound is (tonal information).
The point to note here is that our hearing mechanism is ultra sensitive to time domain distortions. So the fundamental prerequisite in order for any loudspeaker to reproduce life like accurate sound is that its response time (speed) has to match or exceed that of the human ear.
Someone with average hearing can detect time domain errors down to an incredible 25uS (25, one millionth's of a second)or even less if your hearing is very good. The very best ribbon drivers covering 2KHz & above settle in an average of 100uS, the best dome tweeters have a settling time of between 140uS and 180uS, ultra fast midrange units need over 450uS to settle in the 500Hz to 2KHz band and a typical high end 12" bass driver can continue to oscillate and resonate for nearly a second after the initial musical note or impulse stops.
There is a driver which covers the entire 300Hz to 30 KHz band with a blindingly fast rise time of 13uS and does so without any of the ghost echoes and distortions caused by sluggish pistonic drivers slow settling times. It covers 90% of the audible frequency range with both rise and settling times that average over twenty five times faster than the very best pistonic drivers. Even more startling is the fact that this driver is so fast, the 13uS rise time is undetectable by the human ear, even a very good one! How is this possible I hear the sceptical voice cry?!
By refined the worlds only true rippling or bending wave loudspeaker system incorporating linear phase (time and phase coherent) digital crossovers and a genuinely unique cabinet material.
All full range loudspeaker systems are a combination of three equally important components; the driver, the cabinet and the crossover. In a world obsessed with measurements and statistics its easy to forget that it is more important how music sounds than how it measures.
A loudspeaker cabinet is not a passive box. Regardless of its material & construction techniques, a loudspeaker cabinet must be viewed as an active component which is equally important to the overall sound as the driver and crossover. The cabinet is an active energy conversion system, its job is to contain and convert energy, it must deal with the sonic back wave produced by the drivers it houses. Remember that the back wave disappearing into the cabinet is just as loud as the sound flowing into your room!
Creative engineering solutions can convert the kinetic (sound waves) energy of the back wave into heat energy by utilising proprietary viscoelastic materials and techniques.
MDF, plywood, hard wood, phenolic resin or plastic simply can not approach the energy conversion characteristics of this new unique 16 layer Self Damping Compound (SDC).
In acoustics the most important law of physics is, "for every action there is an equal and opposite reaction", so for all the musical sound you hear filling your listening room there is exactly the same amount of sound energy bouncing around inside the speaker cabinet! How can you convert this sound into heat before it bounces back out through the driver diaphragm out of phase!?
The only answer is…. ? |
All I can say is, Manger, either love them or loathe them. I am in the previous camp.As I said earlier Derek, you have taken a brave path, hope you reach your goal financially, because in the end it is all about the money.
Sphere. |
Hi Sphere,
Yes it would be nice to have the income stream of Wilson Audio!
I wonder if Dave ever imagined in the 80's when he was selling cheap cones and domes in an MDF box (watt, no puppy!) for $2,000 a pair that 20 years later he'd get away with selling them for $200,000 in a phenolic resin box! Wow that marketing, er sorry, inflation thing must really be kick'n in!!!
All the best
Derek. |
Dear Derek,
I would say good for him, as he is doing something in his products that seems to have many in the audio world admiring them. I will put it like this, let Overkill do what it is doing best,i.e making a radical product at an approachable price point if possible. Clearly Overkill cannot be sold via the traditional High End supply chain. It can only succeed if you manage to find extremely dedicated resellers and clients who believe in the technical approach, which you will find.Therefore none of the traditional brands are your competition and hence do not matter.
Sphere. |
Hello Sphere,
Yes I agree, we need to do things differently in our marketing and distribution.
Hopefully we will find the right people to work with in the USA and then it will be up to the customers to decide!
"Time Will Tell"
All the best
Derek. |
I hope the following new perspective helps clarify a couple of points on the THD driver distortion front.
If we look at the whole audio chain from source to drivers and look at the audio signal as one continous signal does it really matter where the distortion occurs?
If the true and total accumulative THD of the signal was measured from source through to the output of the loudspeaker drivers, could we measure or hear if the distortion was all in the source, all in the amps or all in the speakers?
If the total system THD figure was say 3% could we tell if each component in the chain added 1% or was the source "perfect" and the amp a super clean 0.0007% so it had to be the fault of the speakers?
Why are some of the worst measuring digital sources (Zanden and most NOS DAC players) reviewed and acclaimed by buyers as the most natural and life-like sounding?
Ditto SET amplifiers and valve pre amps, many exhibit over 1% distortion in real load measurements yet they are again bought and treasured as the most natural sounding. How can they be even close to in performance terms, never mind the prefered choice over many of the "so low its basically zero" distortion amps?
My last question is do we actualy believe that if we replay the most perfect high resolution recording of a powerfull piece of music on a $Million system made up of a THD 0.5 % source, a THD 0.5% amplifiers and a THD 0.5% pair of speakers that our ears will agree and tell us "yes that is 98.5% indistinguishable and a 98.5% perfect reproduction of the live event?
No way on gods green earth!
With current technology, we are obviously a million miles away from being able to reproduce the power and complexity of real music.
My point is this; Our current obsessive "tunnel vision" with THD is focused on the wrong distortion. THD is Total HARMONIC Distortion we need to measure
Total Signal Integrity Distortion (TSID).
This is what I have been focussing on for the last 6 years.
I will make a seperate posting for more on the importance of Time coherence in the audio signal.
In summary current THD only measures amplitude and frequency errors ie THD is two dimensional!
Despite the smoke and mirrors marketing of conventional speaker manufacturers, the very pretty 3 D waterfall plots from speaker measurement software are still only 3D representations of a two dimensional event.
I hope this is of interest and helps further the debate.
"Time Will Tell"
All the best
Derek Wilson
Overkill Audio |
As the US distributor of Manger, I would like to thank Derek for his wonderful explanation of the advantages of the Manger driver. At the upcoming CES, we are introducing a special version of the Zerobox 109 - the AG Silver Edition driven by an ultra fast amplifier (Delta Sigma) from Italy that is flat to 3Mhz. |
In house are the Manger S1 active speakers. My dealer laughed at my buy stating that they suck. I had bought the Audiovector R3 on his recommendation and indeed it is a very great speaker. The R3 was no match to the S1 speakers. The S1 speakers are far superior in sound quality compared to the R3.
Paired with two Rel S812 subs they are an incredible buy. Fast, Zero distortion and simply stunning. Running all Teo Audio IC’s that has that 300B tube magic.
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