Yes Bill, also such a British super product
But ESL’s can’t reproduce earthquakes like ATC can seemingly do without any noticeable distortion.
And ATC’s can even outperform Wilson speakers, amazingly.
Hans
Hi Hans!
I agree a very British super product! Without eqing I find they have a reallyt clear and forward midrange a la Rogers or Celstions likely due to that 75 mm dome mid. Dynamic range is a huge difference though, especially in systems using the SCM 200 or 300.
It is an interesting discussion comparing ATCs or other studio monitors against high-end home hifi speakers. One thing is constant: the dynamic range required of studio monitor speaker systems has been historically higher due to the raw tracking audio being uncompressed. Consumer delivery formats have historically been quite compressed, but these days with 24-bit HD files this difference can be non-existent.
I would say in general high dynamic range is still a primary design criterion of most studio monitor speaker systems, with other characteristics being secondary. I have heard much better imaging with ESLs and even some others like the Watt/Puppy a lucky anesthesiologist here in town owns and I was lucky enough to hear. However to hear an uncompressed drum kit while tracks are being laid down on a big pair of ATCs with subs is a really impressive and visceral experience, one I have never had from a home system.
Cheers!
Howie
I think you might be right, but while ATC is UK-based, it was started by Billy Woodman who is an Australian. That makes him one of ours. 
If dynamics is the primary concern, take a look at the designs by Andrew Lipinski where the goal is on spatial and imaging direction. He is a creature of the studio, his main design is the Lipinski L-707, and offshoots from that. They are definitely meant for studio monotoring.
Lipinski Website
Lipinski Sound L-707 loudspeaker Measurements | Stereophile.com
I use a similar approach in my design, particularly we end up with the same step-response. But I want both dynamics and imaging, because with many speakers I hear a sound that is trapped inside the box. Especially LR crossovers, though they look technically near-perfect, just don't sound right to me, and others.
Just my tuppence worth.
If dynamics is the primary concern, take a look at the designs by Andrew Lipinski where the goal is on spatial and imaging direction. He is a creature of the studio, his main design is the Lipinski L-707, and offshoots from that. They are definitely meant for studio monotoring.
Lipinski Website
Lipinski Sound L-707 loudspeaker Measurements | Stereophile.com
I use a similar approach in my design, particularly we end up with the same step-response. But I want both dynamics and imaging, because with many speakers I hear a sound that is trapped inside the box. Especially LR crossovers, though they look technically near-perfect, just don't sound right to me, and others.
Just my tuppence worth.
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Meh, about the size of my Infinity Kappa 100 towers. My absolute favourite 300lbs. of sound pump, followed by the pair of B&W Matrix 801 S3 in my office.
The Purifi discussion is probably not relevant to an underhung driver and they do exist, even for 15" car subwoofers (120 dB in the car). The current drive is interesting but actually is a window into a more fundamental discussion. The coil in magnet driving a cone model dates back to the early 1920's with Rice and Kellogg (I'm not talking about cereal). The air mass and cone mass balances out the current drive to get a relatively linear response to a voltage input. Its all a lucky balancing act. However once you switch to constant current the output follows the impedance of the driver. I suppose you could tweak a driver to have relatively flat response over part of its range with current drive but overall it will amplify resonances in its response to the associated impedance variations. I think its really only practical with DSP and separate amp per speaker. I don't know of a switching amp that has been optimized to work in current mode so another technical hurdle to overcome.
It would be interesting to see if a negative output impedance on the amp could even further reduce driver distortion? A very tricky circuit to devise.
Other positives on current drive-
1) constant output as the voice coil heats up.
2) constant output no matter how long or small the speaker cables are.
Which takes us to the real speaker market- those small boxes sold in very large quantity that have more technology and sophistication than the most expensive hifi speakers. And the largest selling speakers are those that purport to obey your instructions and otherwise spy on you. They all have dsp and some have dsp that allow a 1/2" driver to handle 5W without getting fried. Its amazing what can be done when the volumes are in the millions. . .
OMG, Geoff Kait, of Machina Dynamica fame, registered an account and is engaging on the ASR forum. That will be a wild ride .
Edit: Argh, one week later he was banned. Now I’m really disappointed. Geoff, if you are reading this, please consider registering here. You may find some audience and certainly more tolerance to your claims.
.Edit: Argh, one week later he was banned. Now I’m really disappointed. Geoff, if you are reading this, please consider registering here. You may find some audience and certainly more tolerance to your claims.
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Didn't recognize the name, though I found mention of him and his business in this thresd about a year ago:
https://www.diyaudio.com/forums/the-lounge/349926-black-hole-100.html#post6328610
I'm sure he could add some color and flavor to the current (no pun intended) measure-cable-distortion thread.
https://www.diyaudio.com/forums/the-lounge/349926-black-hole-100.html#post6328610
I'm sure he could add some color and flavor to the current (no pun intended) measure-cable-distortion thread.
It seems there is a desperate need for burning free time by some here, disregarding the quality of combustion.
Please spare the environment !
George
OMG, Geoff Kait, of Machina Dynamica fame, registered an account and is engaging on the ASR forum. That will be a wild ride
Edit: Argh, one week later he was banned.
So no actual resolution of the age-old conundrum of ....Immovable Mass (opinion) vs Unstoppable Farce ?
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Hi Bill
Yes, in fact near to 20dB reduction in critical distortion - and yes, get things like FR reasonably right and you can hear it, particularly with full-range drivers (a la Nelson Pass did).
But alas, current-drive is not going to be the real end solution. What we need to do is get lower distortion from voltage sources, because that drive will dominate. But here is something I tried to tell Pavel about his measurement: It is not the driver's current, it is the current of the amplifier that is being modulated by the many imperfections of the driver and that this causing that up to an additional 20dB of distortion. But it does teach us one thing, always get the best drivers with low distortion in the first place, because the current of the amplifier reflect it right back into the mix, and distortion smeared in time. That is why Pavel said it was more obvious when measuring IMD, IMO.
As you may know, this is an area that I have some skin in, here the word is used with a certain context.
Yes, the work done by Purifi is indeed interesting and I have been a good student of it. I made a certain comment where my words were selected very carefully where he talked about "impedance modulations" and what part of the impedance is being modulated? The current! Yes, I said "the current of the amplifier!"
What causes this current-based distortion?
It is the difference between the DC resistance Re and the actual measured impedance. This excess inductive impedance (relative to Re) is caused by inductance and change with frequency is because the voice coil is acting as a voltage source that impedes the current of the amplifier (microphones rely on this).
I have in the past called this "back-EMF impedance" and was criticised for that (it is interesting that under current drive, this impedance appears as an actual voltage that cannot impede current under current-drive conditions - it is voltage alright). I have pointed out that these "impedance modulations" do not affect the voltage (assuming voltage source) but cause the current to change as well as the current phase angle to change.
I now have onboard three physicists who have agreed with this analysis. The reason some people hear the advantage of current-drive is that the current source amplifier suppresses that "back-EMF impedance" and hence "impedance modulations" of the current. This is the reduction of distortion right there. That is the mechanism at work and it has been proven by actual distortion measurement (how these measurements were done will be published in time, but they are tighter and revealing than Pavel's, even includes numbers).
I have pointed out to Lars Risbo that his use of the phrase "impedance modulations" is a reference to the current of the amplifier being impeded and modulated. He too agreed with that statement, in fact, called the observation "excellent."
What is for sure is, that in recent years and the last decade there has been an increased re-assessment in understanding (and testing) loudspeakers and how they interact with the amplifier, whether they be voltage or current sources. And something good is coming out of this.
But as I have also pointed out previously, a partial solution is making the amplifier produce that same current at all frequencies; this goes a long way to solve problems with both forms of 'drives - meaning that creating a flat impedance (which determines the current) right across even up to 100KHz, that the output impedance of the amplifier is effectively nullified (and speaker cables too) and the current phase angle of the amplifier is always near zero. And strangely enough, you can hear it quite well.
So Bill, it pays that we all have an open mind. Right?
Cheers, Joe
Edit: PS: The fix that Purifi uses is getting the inductance as flat as possible within the total range of the max peak excursion of the driver. So that at 1KHz the inductance always stays flat at 0.4mH. By the time you get to 10KHz, this is lowered to 0.2mH and must be flat across the whole peak-to-peak (max) linear excursion - the length of the overhung voice coil. I on the other hand, have come up with an alternative solution - neat and very easy to implement if the right low inductance drivers are used. It's about reducing those "impedance modulations."
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What?
Bill, are you quite sane? You used the word 'fix' and that was OK? I use the same word and you call that ignorance?
Here is YOUR exact words:
I think you owe me an apology.
Bill, are you quite sane? You used the word 'fix' and that was OK? I use the same word and you call that ignorance?
Here is YOUR exact words:
I think you owe me an apology.
I suppose if the speaker is doing this via back EMF, that could explain why cables (with differing connection impedance) might sound different. I wonder under what circumstances this is happening? Ear breaking loud perhaps?
Aware of KEFs efforts to make the speaker impedance, as seen by the amplifier, tend toward resistive across the audio band, with their claim that it makes the amplifier not have to work as hard to drive the speaker.
Is that just another way of saying the same thing?
One would think a speaker with darn close to a resistive drive nature would be less susceptible to "mix 'n match" of cables, amplifiers regarding how it sounds. If everyone designed speakers with this aspect paramount, perhaps the mix and match thrash at that level would eventually die among audiophiles. Wonder what impact that would have on the accessory and amplifier industry?
Put a 0.1 ohm across the speaker terminals, a 1 Ohm in series. Your 95db driver is now 85. Let's see the back EMF of the speaker influence the output of the amp it would take to drive that. Burn a bunch of power in the 1? That's what the heatsinks on the back of the cabinet are for. Of course I jest, but there's probably an effective passive technique somewhere between brute force and nothing. Right now I'm listening to "nothing" between the speaker terminals and amp, besides the wire.
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Cancelling voice coil static impedance (Re + any "Le") turns the driver into a full motion control feedback, with the VC generating the sensor voltage (proportional to velocity). As long as the BL is constant, this linearizes the driver, in theory. In practice, BL isn't constant and Re and Le aren't constant either, limiting things severely, though some clever servo schemes to track thermal Re changes have been developed... for example by David Birt (search this forum for more info, from @soundbloke).
OTOH, current drive puts the driver in full force controlled mode with zero local feedback, the microphonic voltage does not re-enter the system. This is often is problematic around system resonance and the main reason I have found, besides the obvious altered frequency response (which can be EQ'd), is dynamic instability, chaotic phenomena like jump resonance which pops up whenever we have nonlinear systems with low damping.
As the Purifi guys have pointed out, current drive helps some but it's not end game solution.
Some Speaker Problems That Needed Solving - PURIFI