[jackman]

AJ is not Ashley James and he has never worked for ATC.  He is an Audiocircle regular and he runs an up and coming speaker company.  I agree with his comments, lots of subjective claims about ATC speakers and no quantitative, objective measurements.   I would imagine if these speakers are so technically superior there would be some measurements provided.  They may sound great but if you don't have proof, please spare us the marketing fluff and unsubstantiated claims.

Cheers

Jack

[Shadorne]

Jack,

All my statements have all been factually correct. You can easily find information about speaker design (Q, driver beaming, voice coil design etc.) including papers written by Dr. Floyd Toole (now works at Harmen Karden). There was a paper published in AES - Audio Engineering Society detailing measurements on ATC then new SL driver. If you join AES then you can get this information but you have to pay for copies (typical all engineering society papers).

If you choose not to believe any of my statements about ATC's design or about well established speaker driver behaviour then nothing I say or do will change that.

http://www.studio-hifi.com/images/Stereoplay_2010-08_ATC_SCM100A_SL_TowerFF-.pdf

http://mixonline.com/mag/audio_highend_studio_monitor/

And sticking to facts, here is a list of some users. The relevance being that these are mostly musicians and audio professionals (back to what I said about ATC fulfilling a niche). You are right to be skeptical of anyone posting in internet forums but I believe this user list can easily be confirmed through google and you will find that many of these professionals are highly regarded by their peers and therefore you can have confidence that they have specific reasons for buying ATC (I described what makes ATC a bit different in a previous post - you can research that also and you will find there are not many speakers with a 3 inch mid range and using massive mid range motors with large voice coils - with a few exceptions, most consumer speaker designs have 1 or 1 1/2 inch voice coils and most often it is a long voice coil in a short magnet gap, a design which tends to be less linear as excursion increases and one that suffers from thermal compression more easily).

Some ATC Owners:

Ed Cherney
Tom Petty
Lenny Kravitz
T Bone Burnett
Pink Floyd
Ryan Tedder
Jack White
Roger Waters
Paul Hager
Bruce Swedien
George Massenburg
Chuck Ainlay
Mark Needham
Michael Piersante
Rick Springfield
John Rodd
Niko Bolas
Peter Stengaard
Rafa Sardina
Steve Perry
Ziggy Marley
Nathaniel Kunkel
Big Kenny Alphin
Ryan Ulate
Chas Sanford
Ryan Freeland
Byron Galimore
Chris Lindsey
Reid Shippen
Michael Fuller
Lyle Workman
Glen Ballard
Adam Hawkins
Danny Leake
Michael Cohen
Diana Krall
Mark Mancina
John Rodd
Herb Tassin
Mike Wells
Ed Hamilton
Beau Burchell
David Bock
Eric Talbot
Greg Hayes
Tucker Martine
Paul Reed Smith
The Killers
John Ovnik
Jason Lehning
Mike Roskelly
Jason Keillor
Robert Caranza

Film Music
Steve Kempster
Dennis Sands
Shawn Murphy
Alan Myerson
Joel Iwataki
Bobby Fernadez
Lyle Workman

Studios and Facilities
Library of Congress
BlackBird Studios, Nashville
East West Studios, Los Angeles
Gavin Luresson Mastering
Doug Sax Mastering
Mike Wells Mastering
Disney Hall, LA
Real Songs, LA
ABKCO Records, New York
The Living Room, New York
The Magic Shop, New York
Blue Man Productions New York
Washhouse Studios, Hawaii
Columbia College Chicago
The Bridge, Glendale
Barefoot Recording, Los Angeles
The Great Divide Studios, Aspen
Manifold Recording, North Carolina
Odds On Studios , Las Vegas
Wire Road Studios, Houston
WGBH Boston
Ex'Pression Center, Bay Area
25th St Recording, Oakland
Front Stage, Nashville
Peabody Conservatory, Baltimore
Java Jive Studios, Nashville
Loud Studios, Nashville


I doubt the list is exhaustive as it does not even mention Mark Knopfler

[Shadorne]

Here is the SCM 19 150 mm driver





Below is the 3 inch dome





As you can see these drivers do indeed have massive motors - this is again fact not fluff.

Sorry about the size, I was unable to reduce the pics.

[Danny Richie]

While the facts are being thrown around over here, let me point out a few things so we don't misinterpret them and draw unfounded conclusions as a result.

My statements are factually correct. ATC do have low distortion at higher SPL than most speakers which is a distinct advantage. I agree that at moderate SPL levels the differences in performance become small.

Harmonic distortions are a percentage of output. They go up and down with SPL level. So it is constant.

Secondly a harmonic distortion is often very hard to separate from the input signal. It tends to be along for the ride. So once you are already down to a certain level it is very hard to pick it out. It becomes very much like trying to pick out just one voice in a singing choir of 100 people. If that one guys is slightly off key it is still hard to hear because he is still in time and a small percentage.

Now a distortion with a time element involved like some stored energy, break up of a woofer cone, or ringing effect becomes much easier to hear. A speaker that dissipates that stored energy quickly and has a clean spectral decay will clearly have the characteristics that you guys are describing with these speakers. And I suspect these speakers are very good in that regard. In sticking with the example I just used above. Imagine that in the 100 piece choir, instead of the one guy being slightly off key, imagine him being half a second late on his part. Now you might start to hear his effect.

And AJ has a very valid point. Amplitude changes that will cause a variance and is also distort the signal. And this is very much true for the off axis and not just the on axis. Most of us don't listen to our speakers outdoors. So the off axis makes a big difference. If there is an un-evenness in the off axis then there could be some un-evenness in the room response. And this isn't just about the dispersion characteristics of a driver or the horizontal off axis only. The vertical off axis is even more important as ceilings tend to be the largest reflection point in the room and almost always untreated. And the vertical off axis has as much to do with phase relationships of the drivers and the ranges and slopes used in the crossover as anything.

And while we are on the facts...

3.3KHz in the bigger models and on SCM19 or 20 I believe the grafted 3" dome operates up to 2.8KHz - in both cases this means that you are getting much more even dispersion through the mid range. This is a fact.

Please allow me to shed some light on this. The heart of the mid-range (the true mid-range) is in the 300Hz to 500Hz range. A driver that is a true mid-range driver designed to really cover the mid-range will handle a range from just under 200Hz to 1kHz. Above those ranges are not mid-ranges. And the 300Hz to 500Hz is the one area that you want to avoid a crossover point. You don't want dissimilar drivers, with a different offset, and a phase shift to be in that region.

So statements like this are not true.

So the highly prevalent two way speaker designs with 6" woofers generally tend to have a mid range scoop due to the narrowing of the off axis response in the upper midrange (many people like this sound as it emphasizes treble and bass).

Beaming occurs as a driver begins producing a wavelength that is shorter than its diaphragm. So  6" driver (or one with a 6" diaphragm) for instance will just start a narrowing of its off axis response at 2.3kHz or so. That is a 6" wavelength. This is already well above the mid-range.

And I am not knocking ATC at all. There are reasons that they may sound very good. But some of the reasoning I am seeing here is not it.

[Stuart]

These ATC speakers, particularly the SCM100A are simply the best speakers that I have heard for the money. They can produce dynamics like no other speaker in its price range and sound as good at crazy spl levels. I have yet to hear any distortion and compression from them and I have owned speakers costing twice as much from TAD etc

There is no better monitor or Hi-end speaker period.

[Danny Richie]

These ATC speakers, particularly the SCM100A are simply the best speakers that I have heard for the money. They can produce dynamics like no other speaker in its price range and sound as good at crazy spl levels. I have yet to hear any distortion and compression from them and I have owned speakers costing twice as much from TAD etc

Stuart,

When I listened to their whole product line this was their best sounding model in the line. However, I did get the feeling that the rest of the product line using passive networks might have been being held back considerably with budget level crossover parts. And the passive models were certainly being held back by the electronics used to demo them in the store that I auditioned them in.

Upgrade the passive models with some decent parts and put them on better gear and some of those models my have really beaten up the powered model.

There is no better monitor or Hi-end speaker period.

I like the line and think of them as being very good (especially the drivers), but find them a long way from being able to use them in a statement like that.

As a designer I had a hard time understanding why they designed a speaker with so much surface reflection from the front baffle. And as a listener I had a hard time getting past that. That element alone is not at all good for imaging and sound stage.

[MaxCast]

Shadorne, please reduce the size of the pics so one can read this thread a little more easily.

[Shadorne]

Harmonic distortions are a percentage of output. They go up and down with SPL level. So it is constant.

Distortion is measured (at safe volume levels) as a percentage of output but you will find that with speaker drivers the distortion will increase at greater cone excursion or higher SPL. Here is an example of increased distortion at 95 db SPL. At 50 Hz the distortion is -22 db when at 95 db SPL compared to -27 db at 90 db SPL. This will get worse at even higher SPL's.  It even shows how the tweeter is compressing quite badly (probably thermal compression).

http://www.soundstagenetwork.com/measurements/speakers/wilson_wattpuppy8/

[Shadorne]

The heart of the mid-range (the true mid-range) is in the 300Hz to 500Hz range. A driver that is a true mid-range driver designed to really cover the mid-range will handle a range from just under 200Hz to 1kHz. Above those ranges are not mid-ranges. And the 300Hz to 500Hz is the one area that you want to avoid a crossover point. You don't want dissimilar drivers, with a different offset, and a phase shift to be in that region.

I don't think many people would agree that the mid range is so narrow. As for speaker design philosophy, I am sure everyone has an opinion but suffice to say that ATC have stuck to practically the same design for 30 years or so. It may not be totally conventional - if you consider the most popular two way design to be "conventional" (6 inch woofer up to somewhere between 2.4 or 4 KHz and a tweeter above that) but it certainly works well enough.

[Shadorne]

As a designer I had a hard time understanding why they designed a speaker with so much surface reflection from the front baffle. And as a listener I had a hard time getting past that. That element alone is not at all good for imaging and sound stage.

You are correct. The big speakers like the ATC 100's and upwards will only image their best in a soffit mounting, which ATC recommends and which you will find in most high end studios. (Like Mark Knopfler's studio in the photo I included above - you see small ATC SCM 25 on the meter bridge but the large ATC SCM 300 main monitors are mounted into the wall so the baffle is flush with the wall)

This is also a well studied phenomenon that nearby reflections (like edge diffractions) tend to confuse the listener to the sound source (a problem that goes away as you get about 3 feet away from the speaker or as you get into designs with narrow baffles of roughly a foot or less - as far as I can tell the smallSCM 19/20 does not suffer from edge diffraction as they both image very well but I would advise users to keep the grills on the SCM 20 whereas with the profile of the SCM19 I think it is just a question of taste)

I completely agree with you on this point. I believe the reason for ATC to use simple wide baffles is to keep cabinetry costs lower/simpler with the knowledge that most high end users in the pro world will soffit mount them. In the large models they do make an EL 150 that has a curved front surface that probably images better than the standard large designs when freestanding but it is not exactly affordable to most people.

BTW - Soffitt mounting also eliminates quarter wave cancellation from bass drivers and it is regarded by some acoustic experts as the ideal way to set up speakers although it does tend to excite room modes more than a freestanding placement within the room. (Generally studios are carefully designed to reduce room modes and are extensively acoustically treated to address reflections as well as to help tame room modal issues)

[Danny Richie]

Distortion is measured (at safe volume levels) as a percentage of output but you will find that with speaker drivers the distortion will increase at greater cone excursion or higher SPL. Here is an example of increased distortion at 95 db SPL. At 50 Hz the distortion is -22 db when at 95 db SPL compared to -27 db at 90 db SPL. This will get worse at even higher SPL's.  It even shows how the tweeter is compressing quite badly (probably thermal compression).

http://www.soundstagenetwork.com/measurements/speakers/wilson_wattpuppy8/

Think about what is being shown there. The increase is at 50Hz. Those are in areas where the cone exertion is getting higher. There could be some rise due to cone flexing. It is also hard to accurately measure those ranges. They cut the measurement off at 50Hz. And measuring those ranges will get a little inconsistent. Also that peak at 1kHz is still well below the tweeters range. That could be a little break up in the woofers range. 

[Danny Richie]

Keep in mind too that these studios are using these for mixing and listening for their own preferences. They aren't like us wacky audiophiles that are trying to recreate a 3 dimensional sound stage.

[Danny Richie]

I don't think many people would agree that the mid range is so narrow. As for speaker design philosophy, I am sure everyone has an opinion but suffice to say that ATC have stuck to practically the same design for 30 years or so. It may not be totally conventional - if you consider the most popular two way design to be "conventional" (6 inch woofer up to somewhere between 2.4 or 4 KHz and a tweeter above that) but it certainly works well enough.

Think about the range that the human voice falls into... Even most instruments.



I have many times played a piece of music and watched the RTA on my Clio to see what range most things fall into. Vocals are usually in the 300 to 500Hz range as a fundamental.

[Shadorne]

Keep in mind too that these studios are using these for mixing and listening for their own preferences. They aren't like us wacky audiophiles that are trying to recreate a 3 dimensional sound stage.

Yes I agree. Audio Physics and other similar narrow designs excel at 3D imaging. I can appreciate other designs for what they bring even the Bose cube speakers (Acoustimass) imaged well even though I would not regard them as audiophile quality but they did image extremely well.

ATC's also sound or are voiced deliberately to sound fairly similar (just more dynamic range and more bass extension as they get bigger). ATC don't change much over the years. You can still get parts for speakers ATC made 30 years ago. These kind of things are what studios/pros appreciate. It means that professionals are often familiar with the sound and can work with them in different locations and techs can repair what the users often blow up.

Anyway I hope my comments here help for those who are interested. I would definitely say that ATC is NOT the best choice for everyone - far from it.  If anything the lack of mid range scoop means they can sound harsh on some of the modern dynamically compressed pop/rock/metal music (where limiters are used to squash the music and make everything equally loud - or sometimes referred to as the "loudness wars" - a process that adds distortion). ATC's also need to be played louder than most designs to get the best balance in sound (sound best at live or close to live music levels). The bass is punchy and light and lacks the warmth that you typically get from most modern ported speakers. So those who like Dr Dre Beats Pro headphones and want a design that gets the room humming in the bass should look elsewhere.

[AJinFLA]

AJinFLA,
My statements are factually correct. ATC do have low distortion at higher SPL than most speakers which is a distinct advantage.

No. You have to repeat it 3 times on the internet before it becomes a "fact".
This is the standard when you have zero data to support "facts".

Are you by chance the Ashley James that used to work at ATC?

Not unless you repeat it twice more.

cheers,

AJ

[Pete Schumacher]

For a bit of perspective, here's a shot of a 2-way using an 8" Vifa NE225W-04 crossed to a waveguide loaded Dayton RS28A tweeter at 1KHz.  This was with a 10W input for roughly 98dB@1m output.  Distortion across the band from 100Hz on up remains below 1%.  (the blip at 130Hz is due to boundary conditions)



And here's a set of off axis plots of the same setup but using the silk dome version of the RS28.



These are very good drivers even if somewhat "budget" level, and they are delivering fantastic measured performance by any objective standard.

The ATC mid is indeed very good and measures exceedingly well.

Here's a distortion plot of that dome taken by John Krutke.



On the other hand, here's a distortion sweep of the Tang Band 3" dome also taken by John under the same conditions.  Notice especially the reduced 3rd harmonic content compared to the ATC above 500Hz.



I only post these plots to show that while the ATC speaker may indeed measure well, it is by no means "at another level" compared to more budget drivers available.  And while the off axis response of the ATC may indeed be good, it is certainly no better than the 8" 2-way plot posted above. 

[AJinFLA]

Distortion is measured (at safe volume levels) as a percentage of output but you will find that with speaker drivers the distortion will increase at greater cone excursion or higher SPL. Here is an example of increased distortion at 95 db SPL. At 50 Hz the distortion is -22 db when at 95 db SPL compared to -27 db at 90 db SPL. This will get worse at even higher SPL's.  It even shows how the tweeter is compressing quite badly (probably thermal compression).

http://www.soundstagenetwork.com/measurements/speakers/wilson_wattpuppy8/

Where is the ATC data like this?
Notice the non-linearities at 5k with the direct radiator bling dome, at 95db?

[Shadorne]

Pete,

The plot you show of the two way shows extremely good dispersion. I agree with everything you say. ATC are not on another superior level but ATC designs fulfill a niche market very well. The Tang Band 3 inch is an excellent driver but I doubt it can play as loud cleanly as ATC's Super 3inch dome (nor should one expect that given its modest price). ATC excel at clean sound at higher SPL a niche that studios like.

[AJinFLA]

And sticking to facts, here is a list of some users. The relevance being that these are mostly musicians and audio professionals

The fact that they are used by professionals and have big magnets is not in dispute.
And their "Q" is quite normal. They will radiate into rooms with modes like any 2nd order box speaker.


cheers,

AJ

[Shadorne]

Where is the ATC data like this?
Notice the non-linearities at 5k with the direct radiator bling dome, at 95db?

The german magazine stereoplay has some measurements of ATC 100's. I gave a link above.