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ATC SCM50 measured performance vs. others 2013
Old 23rd December 2013
  #1
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ATC SCM50 measured performance vs. others 2013

Hi guys, Since I wanted to buy a pair of active ATC SCM50 I was trying to have a look at any measurements of both single drivers and speakers themselves. Suprisingly they are almost none apart from their midrange SM75-150.

I found an interesting discussion about how pourly behave ATC SCM50 when measured.

ATC SCM50 measured performance vs. high quality studio monitors - AudioSmile Forum

Since that discussion is pretty old and almost eight years passed I want to ask the same questions.

I have found out that there are other excellent designs which are known for good performance and good measurements. These companies have published more (or less) detailed measurements. The question is why ATC doesnt do it? A lot has changed in speaker design since ATC SCM50 had been build many years ago. I have an impression that once people start to look at the measurements the myth of the most accurate monitors will disappear. People also claim that these speakers break many design rules.

Some good speakers I find particulary attractive with their performance and measurements:

Opal Event
Event Electronics | Reference Studio Monitoring | opal

JBL LSR6332
JBL :: Product

Unity Audio - The boulder
The Boulder studio monitor

Gedlee Abbey
Abbey

Pi Speakers
Pi Speakers - unmatched quality and state-of-the-art performance

Genelec
http://www.genelec.com/

ME Geithain monitors
http://www.me-geithain.de/index.php/en/

and many DIY products like here:

Gainphile: S15 - Econowave DSP


I, myself was caught by this thinking that ATC is the best. I have read a lot and started thinking that this myth is not supported by any way by any professional measurements. Come on, we live in 21st century and one can expect a decent measurements for a studio monitors of such a high price tag.

Nonetheless, I can find one reason why I will probably buy a pair to check them out. I do belive that these speakers had been one of the most popular studio monitors in the past several years. Therefore many excellent records were mixed with them and bore their sonic "trace". In order to hear exactly the same what the enginner heard it would be wise to listen to the music on the same speakers in similar conditions.

I am interested in genuine input if I am right or wrong with my thinking.
Old 23rd December 2013
  #2
Aren't you over thinking this? All speakers are based on a series of compromises - like all electronics - and, like electronics, measurements don't tell the whole story

If the most valuable criterion for a monitor is to create mixes that translate well to other systems, how does the ATC SCM50 rank? That'd be worth knowing. Certainly more valuable than distortion figures

Nick Froome
Old 23rd December 2013
  #3
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Particularly with something as chaotic as a speaker system, measurements are only valid when all systems are measured under identical conditions using identical equipment/the same room/same air temperature/humidity/SPL/yadda yadda.

Comparing speakers with measurements is like comparing food by looking at it's chemical content.

I've seen ATC's own amplitude response measurements for the SCM50 at the ATC factory and they look extremely good. Amplitude response is only a small part of the story too.
Old 23rd December 2013
  #4
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Also modern SCM50s are quite some improvement/step-up over SCM50s of 15 years ago - the same thing but better. My (~20 year old) SCM20s have been worked on by ATC and bought pretty much up to modern spec and they still sound like the same speaker - just a much better version of it.

The truth is that speakers of 20 years ago weren't that far off the speakers of today despite what many manufacturers would like you to think. Okay so most manufacturers are putting DSP in their boxes, but this is only necessary when you haven't got the speaker to acoustically behave properly in the first place.

IMO, the underlying principles in their driver design is what makes ATC so good, and is something many other manufacturers seem to completely re-think with each new model. The other stuff continues to march along the way it always has, incremental improvements in manufacturing and materials bringing incremental improvements in performance.
Old 23rd December 2013
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Quote:
Originally Posted by dziemian View Post
I, myself was caught by this thinking that ATC is the best. I have read a lot and started thinking that this myth is not supported by any way by any professional measurements. Come on, we live in 21st century and one can expect a decent measurements for a studio monitors of such a high price tag.
[...]
I am interested in genuine input if I am right or wrong with my thinking.
If you were thinking that "ATC is the best", in the sense that they provide the most optimal measurement results, then you may be up for a surprise. But the obvious question that needs to be asked here, is if the main criteria for determining a studio monitor's quality is what quality of measurement data it provides. And even if that is true, what kind of measurement data are considered optimal? Even the most high-end monitors can have some attributes that measure poorly, even though they measure incredibly well in some other attributes. This is because the art of speaker design is an art of managing technical compromises.

Here are some measurement results for the ATC SCM25A Pro, provided by Resolution:
http://resolution.nodecube.net/produ...M25A%20Pro.pdf
Summary: Relatively flat frequency response, very good waterfall plot, but a poor step response with some time-smearing between the drivers.

I've done a handful of mixes on the SCM25As myself, and to me their greatest achievement is that they in addition to having a certain sense of incredible mid detail, they also provide very good contrast between good and bad mixes. I would say this contrast is greater on the SCM25As than on any other studio monitors that I've worked on. I don't currently work on ATCs, but I can see why they are favored by so many.

I'm not quite sure how to end this post other than with a simple sentence: Different types of monitors suit different kinds of people, some measure well and some don't.
Old 23rd December 2013
  #6
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I believe that speakers which perform well in terms of on and off-axis response, polar plot etc are essential. And all the speakers from my previous post are good in this matter. I am not saying that ATCs are bad but it would be nice to have a possibility to look at them closer. For majority it doesnt matter, for me it does. I had some fun with my DIY speakers and nice little device called DEQX. It actually a DSP unit, active crossover and EQ. Thanks to that little beast and diffrent speaker designs I realized how important are all these factors. I was able to even my frequency response to +/- 1db from 40Hz - 20 kHz. And the diffrence was substantial. But to build a good set of speakers you need a lot of time and money. With the speakers I mentioned I believe I can be happy in both fields ie performance and measurements. As I said I still wanted to try ATCs but I stopped beliving they were superior.

In your example of ATC SCM25 look how badly the tweeter is implemented.
http://resolution.nodecube.net/produ...M25A%20Pro.pdf
In new designs you wont find these troubles. Maybe because most of new concepts include waveguides.

I have a feeling that most positive comments come from the use of their midrange unit. It is indeed one of the best on the market. But the rest is design of the 80'. There is high time to move on. If they wont develop their designs they will end up like Nokia which overslept smartphone's time.
Old 23rd December 2013
  #7
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1. There is no standard way of measuring speakers

2 When it comes to low distortion drivers nobody beats ATC.

3 loudspeaker measurements really don't translate to sonics.

Listening will get you further than looking at specs.
Old 23rd December 2013
  #8
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Those measurements are only showing you how that speaker measured under those conditions.

How far away was the microphone from the speaker?

Which microphone was used?

Is the amplitude response an averaged plot of multiple measurements from multiple angles? Any HF response will look like absolute chaos when measured from a single point unless you fill the speaker up with DSP to make it look smooth (causing bumps and unevenness when measured from another position).

Also where do these 'issues' fall? Are they inside the vocal range or not?

Off-axis power response from ATC is better than most - very small (3") driver = wide dispersion.

Your ears do not hear linearly the same way a spectrum analyser or measurement microphone/computer plot does. These are tools which help a designer achieve their goals, and can take you some part of the way to finding out why a speaker may not be sounding right. There are plenty of speakers on the market which measure out spectacularly well in many respects, but actually sound pretty poor when subjected to musical content.
Old 23rd December 2013
  #9
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Quote:
Originally Posted by ddageek View Post

3 loudspeaker measurements really don't translate to sonics.

Listening will get you further than looking at specs.

Really???? Then check this out.

Audio Musings by Sean Olive: How to Listen: A Course on How to Critically Evaluate the Quality of Recorded and Reproduced Sound

I used that software to listen to music with irregularities on the frequency response and I find that statement far from truth.
Old 23rd December 2013
  #10
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Quote:
I have found out that there are other excellent designs which are known for good performance and good measurements. These companies have published more (or less) detailed measurements. The question is why ATC doesnt do it?
Neither does PMC. I've listened to them several times (when the opportunity presented itself) and was under the impression that the "incredible midrange detail" that their fans rave about is due a subtle non-flat frequency response through that range (i.e. push). Maybe that's why they don't publish the measurements.

Harman International (parent of JBL) has done fairly extensive loudspeaker evaluations employing blind (unsighted) listening comparison techniques to eliminate bias and cheating. The speakers that inevitably get the highest opinion score are the ones with the flattest, most uniform frequency response.
Old 23rd December 2013
  #11
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Quote:
Originally Posted by dziemian View Post
I believe that speakers which perform well in terms of on and off-axis response, polar plot etc are essential.
In that case, ATCs are not for you. They are designed specifically to have a wide +/- 80 degree horizontal dispersion, yet a narrow +/- 10 degree vertical dispersion. The latter is to reduce the amount of reflections that would normally come off mixing consoles or desks. This dispersion characteristic is an active design decision that ATC has chosen for their speakers, and they advertise it very proudly on their web pages.

So I guess that in your case, if on and off-axis response is most important for you, then omni-directional speakers are the way to go, or alternatively speakers based on co-axial design principles if you only need the smooth off-axis response within a certain area.
Old 23rd December 2013
  #12
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Quote:
Originally Posted by Hjelmevold View Post
In that case, ATCs are not for you. They are designed specifically to have a wide +/- 80 degree horizontal dispersion, yet a narrow +/- 10 degree vertical dispersion. The latter is to reduce the amount of reflections that would normally come off mixing consoles or desks. This dispersion characteristic is an active design decision that ATC has chosen for their speakers, and they advertise it very proudly on their web pages.

So I guess that in your case, if on and off-axis response is most important for you, then omni-directional speakers are the way to go, or alternatively speakers based on co-axial design principles if you only need the smooth off-axis response within a certain area.
The ±10º thing is to do with phase coherency, not a 'horn-like' dispersion (or amplitude attenuation). Phase coherency across the vertical plane cannot be maintained on any vertically-orientated multiple-driver setup except in a coaxial design (like the Gethains). However a coaxial design also introduces other limitations and issues. Compromises compromises.

The dispersion of ATC speakers gradually narrows a little as you go from low to high frequency, although they are still 'wide' even near the top of the tweeter's passband. This is important, a gradual transition from wide to slightly-narrow(er) - this is what the OP is referring to. Omnidirectional broadband speakers don't exist.

The no.1 issue with dispersion is usually down to narrowing or 'beaming' midrange - causing a (sometimes pretty huge) dip in the off-axis energy of the upper-midband, right where the most critical part of the vocal information lies. This is why ATC uses the 3" midrange.

Quote:
Originally Posted by tpad View Post
Neither does PMC. I've listened to them several times (when the opportunity presented itself) and was under the impression that the "incredible midrange detail" that their fans rave about is due a subtle non-flat frequency response through that range (i.e. push). Maybe that's why they don't publish the measurements.
Which ones have you listened to? I've found some PMCs to be superb across the midband, others not so. It seems quite inconsistent from one model to another.

Quote:
Originally Posted by tpad View Post
Harman International (parent of JBL) has done fairly extensive loudspeaker evaluations employing blind (unsighted) listening comparison techniques to eliminate bias and cheating. The speakers that inevitably get the highest opinion score are the ones with the flattest, most uniform frequency response.
Yes, linear amplitude response is ideal, although in order to be sure that speaker A has a more linear amplitude response than speaker B, they must both be measured under exactly the same conditions. This is why ATC do not publish their measurements, as they know they aren't remotely useful when it comes to comparing them against measurements made by other manufacturers.

Quote:
Originally Posted by dziemian View Post
Really???? Then check this out.

Audio Musings by Sean Olive: How to Listen: A Course on How to Critically Evaluate the Quality of Recorded and Reproduced Sound

I used that software to listen to music with irregularities on the frequency response and I find that statement far from truth.
What do you mean, irregularities on the frequency response?
Old 23rd December 2013
  #13
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Quote:
This is why ATC do not publish their measurements, as they know they aren't remotely useful when it comes to comparing them against measurements made by other manufacturers
More likely they are trying to hide something. If I'm going to spend a lot of money on a piece of hardware, I want to see detailed measurement data that tells me what I'm getting. Whether YOU THINK it is useful or not is irrelevant. If I don't see the data, I naturally become suspicious. Genelec, Neumann KH, ADAM, JBL, etc all provide parametric data for their product, so there is no valid excuse for PMC and ATC not to do likewise!
Old 23rd December 2013
  #14
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Maybe they are hiding something. Or maybe they believe that people should not put too much trust into measurements that the manufacturers have done themselves? When showing data in advertising, it's about bringing attention to data that looks positive, and thus turning the focus away from any negative data. Maybe ATC simply believes that people should try mixing on their speakers and find out first hand if ATCs work well as a studio monitor, instead of relying on all the advertising magic. In Aristotle's teaching of rhetoric this is called using different modes of persuasion - in this case ATC is using ethos instead of logos. I'm not saying that one mode of persuasion is better than the other. But they are different approaches to the same result.
Old 23rd December 2013
  #15
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PT Barnum: The world is full of suckers ..... just wait 5 minutes and another one will come along. Get it?
Old 23rd December 2013
  #16
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After years in the business, working with manufacturers, I have learned one truth: there are a myriad of ways to manipulate test data to aid the sales department.

I never forget visiting to one of the engineers in the mic department at EV in Buchanan, back in the early 80s, showing me how to manipulate the frequency chart data by speeding up the pen speed on the chart recorder. "See you can make the response curve look much smoother, the pen is moving so fast it does not show the tiny details". Slow the pen speed down and it shows all the details and it looks awful. Same exact measurement, different results, which do you put in the brochure? The conversation I was having with him was why another manufacturer's chart looked so good and EV's looked so bad. SO this is a very simple example but believe me, there a thousand ways to play with measurements.

Another issue, how the measurement was done. As mentioned here rooms change everything. To get accurate measurements, we seek a space free from reflections, an anechoic chamber. The size of the chamber and its construction determine how good it is at providing a good measurement environment. Do you think all the different manufacturers, small and large, own sufficient sized chambers, have the same measurement mics, have their systems all coordinated to be "the same" across the industry, so measurements are all done exactly the same and therefore are directly comparable?

So, if one company's measurement is not comparable to anyone else's, how does that measurement become a universal truth and a basis for critical decision making?
Brad
Old 23rd December 2013
  #17
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So why audio manufacturers has never tried to propose a standarized set of measurement, same for everyone. Because it is easier to claim that your product is superior then to prove it. The ATC claims +/- 80 degrees horizontaly but is not true for the whole frequency. It is true to frequencies up to 8khz. The rest is not so nice. So it is half true what they are saying. In my personal opinion the design is fine up to 3,5khz crossover point, then it gets worse. I believe it needs a small tweeter in a waveguide. Some more example on ATC SCM50. The box is rectangular (problem with standing waves inside), diffraction on straight edges (you need always grills on), bad center to center distance between tweeter and mids, badly implemented tweeter (in my opinion). I know there are always trade-offs but they have no standard at all in their speakers. Some speakers are rectangular (SCM50, SCM20), the other are rounded (SCM70, SCM20 pro), some like SCM50 have their tweter and mids off-center for dealing with diffraction, the others basically the same like SCM70 have them on center. I am pretty sure that once measured in a professional institution they all would measure diffrently (no suprise) and you would not like what you see. And to remind you we are talking here about speakers worth $27 000 for a pair of ATC SCM50 anniversary or SCM70 and $13 000 for ATC SCM50 ASL pro.

And this is all we have on ATC SCM50from the producer:
http://www.atcloudspeakers.co.uk/hi-...-series/scm50/

ATC SCM50 is a LEGEND. But it became a legend several years ago when there was no so big competition and I dont think it still holds true nowadays when you can find many fine studio monitors. Without proves it is just people who still claim their superioriority and people can be mistaken.

Once more. I still think ATC SCM50 are very fine speakers good for audiophiles and I want to have a chance to listen to them. Maybe modify them a little. But it is really hard for me to support the idea that they are the best studio monitors available out there.

On the other hand to give a positive example I highly appreciate what Dr Floyd Toole did to audio community by writing Sound Reproduction book and all his research. If I am not wrong the speakers below are built according to his philosophy but this paper is also an excellent example how a spec sheet for any loudspeakers should look like. I havent listened to them yet but I can have my hand cut off if they sound bad.

http://www.jblpro.com/BackOffice/Pro...BL.LSR6332.pdf
http://www.jblpro.com/catalog/genera...x?PId=26&MId=5

Please also read one of his articules on audio reproduction "Science in the service of art".
http://www.theaudiocritic.com/back_i...ritic_28_r.pdf

I cant agree again that measurements are not important for listening. I assure you that all speaker manufactures do measure their speakers but few are willing to show what is the outcome of these measurements. If they dont there is something wrong with the design what measurements would cleary indicate. I agree you still need to listen to the speakers you are willing to buy but at least I would know where to start from.

I think there is one main diffrence between many commercial manufacturers and DIY builders. In DIY community if you claim you have superior design you have to prove it with your measurement before anyone wants to listen to them. Apparently many producers either think we are too stupid to understand measurements or they want to hide some imperfections. You can always write a fairy tale about problems with consistency of the measurements but some other producers somehow still measure, publish and explain measurment conditions on their websites. It is up to me if I believe in them or not and they can be always verified by the third party.

For example some DIY designs from Dr Linkwitz which are considered as excellent sounding. Just see how much information you can read about these designs.

http://www.linkwitzlab.com/
Old 24th December 2013
  #18
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I'm trying to answer the question you posed in the opening thread post, but it's proving rather difficult for any of my suggestions to be taken on board. There are plenty of manufacturers who do not publish measurements, and there are plenty who do. Mackie HR824s have just about the flattest frequency response of any monitor I have ever seen, yet in practice this is clearly not the case. I have not seen any positive correlation between well-engineered speakers and measurements in the marketing material.

Quote:
Originally Posted by dziemian View Post
So why audio manufacturers has never tried to propose a standarized set of measurement, same for everyone. Because it is easier to claim that your product is superior then to prove it.
No, it's because measuring speakers properly is an incredibly expensive and difficult process to go through - everybody has their own idea about how best to do it. Again, compromises compromises (much like the design). There is no finite truth when it comes to this stuff, any speaker designer will tell you this.


Quote:
Originally Posted by dziemian View Post
The ATC claims +/- 80 degrees horizontaly but is not true for the whole frequency. It is true to frequencies up to 8khz. The rest is not so nice.
Do you know anything else about that measurement? It's a rough guide. I'm not sure what you mean by 'the rest is not so nice' - I guess you have some rock-solid measurements showing this?

8KHz is a wavelength of around 1.6" - the diameter at which you would expect many waveguide-loaded tweeters to start to narrow somewhat. As I said above, ATCs narrow gradually from their lowest frequency to highest, and there is always going to be more narrowing at the highest frequencies due to fundamental basic laws of physics. How much narrowing? I can't tell you, it's not much though as I can sit way off-axis of my SCM20s and still find plenty of detail in the top-end.


Quote:
Originally Posted by dziemian View Post
So it is half true what they are saying. In my personal opinion the design is fine up to 3,5khz crossover point, then it gets worse. I believe it needs a small tweeter in a waveguide.
This is exactly what ATC use in all of their speakers but the largest - a 1" tweeter in a waveguide.

Quote:
Originally Posted by dziemian View Post
Some more example on ATC SCM50. The box is rectangular (problem with standing waves inside),
No issues with standing waves - at these frequencies (where the box's internal acoustics could start to become an issue 350-400Hz upwards) the midrange driver has taken over which is closed-back.

Quote:
Originally Posted by dziemian View Post
diffraction on straight edges (you need always grills on),
Rounded edges on the professional models so no grilles required. It's only the domestic versions (which I use) which need the grilles - sensible considering they're going in living rooms and domestic spaces.

Quote:
Originally Posted by dziemian View Post
bad center to center distance between tweeter and mids,
Do you mean too far or too close? Further would mean you make the vertical dispersion narrower. Closer means you can't fit in well-engineered drivers.

Quote:
Originally Posted by dziemian View Post
badly implemented tweeter (in my opinion).
I've always found the top-end on SCM50s (with the newer SEAS tweeter) to be superb. The new ATC tweeter is a step up again.

Quote:
Originally Posted by dziemian View Post
I know there are always trade-offs but they have no standard at all in their speakers.
Except for exactly the same amplifier design & electronics, exactly the same crossover points and electronics across all the three-ways (except different LF driver levels to compensate for the different efficiencies in small & large drivers), and exactly the same mid/hf driver array across all three ways.

Two ways are of course going to be different as there are other compromises to be made, nonetheless I've always been amazed how close my SCM20s sound to SCM50s, so maybe you heard an abused pair?

Quote:
Originally Posted by dziemian View Post
Some speakers are rectangular (SCM50, SCM20), the other are rounded (SCM70, SCM20 pro)
They do offer a rounded-version of the SCM150, but it comes with a frightening price-tag. Not sure anybody would ever be able to buy their speakers if they all came in rounded enclosures. Plus the advantages of a round-box design are pretty small over a rectangular box with smoothened-off edges.

Quote:
Originally Posted by dziemian View Post
, some like SCM50 have their tweter and mids off-center for dealing with diffraction, the others basically the same like SCM70 have them on center.
Not sure why you keep bringing up the SCM70 - a weird speaker designed more for home theatre use than anything else I believe. I've only ever seen one pair and never heard them.

All the three-ways have off-set midrange/tweeter arrays for exactly the reason you give.

All the two-ways are centrally orientated because it would screw with the axis of phase-cohrency between the midrange and the tweeter. Again compromises must be made in a two-way, and all the two-ways I have heard with off-set tweeters suffer from imaging issues.

Quote:
Originally Posted by dziemian View Post
I am pretty sure that once measured in a professional institution they all would measure diffrently (no suprise) and you would not like what you see. And to remind you we are talking here about speakers worth $27 000 for a pair of ATC SCM50 anniversary or SCM70 and $13 000 for ATC SCM50 ASL pro.

Well being pretty sure is different to being certain, and assumptions are undeniably non-scientific (if science and observation is what you're aiming for which it quite rightly seems to be).

Quote:
Originally Posted by dziemian View Post
And this is all we have on ATC SCM50from the producer:
SCM50 | ATC Loudspeakers
Go round the factory and ask them anything - they'll answer it for you. I've been there and they don't hold back any secrets about their designs or how they are built.

Quote:
Originally Posted by dziemian View Post
ATC SCM50 is a LEGEND. But it became a legend several years ago when there was no so big competition and I dont think it still holds true nowadays when you can find many fine studio monitors. Without proves it is just people who still claim their superioriority and people can be mistaken.
It's not to do with anybody claiming superiority. No company is going to turn round and say "our products are okay but not as good as the new stuff", even if that was the case with ATC (which it isn't) - they wouldn't go out and put it up on their website on in their marketing would they? No company would.

Quote:
Originally Posted by dziemian View Post
Once more. I still think ATC SCM50 are very fine speakers good for audiophiles and I want to have a chance to listen to them. Maybe modify them a little. But it is really hard for me to support the idea that they are the best studio monitors available out there.
Nobody is asking you to support the idea - everyone has their own idea about the best monitors (for some it is still the NS10, other people swear by d'apollito/MTM arrays, which are still another compromise). Again, there is no finite truth or when it comes to this stuff.

Quote:
Originally Posted by dziemian View Post
On the other hand to give a positive example I highly appreciate what Dr Floyd Toole did to audio community by writing Sound Reproduction book and all his research. If I am not wrong the speakers below are built according to his philosophy but this paper is also an excellent example how a spec sheet for any loudspeakers should look like. I havent listened to them yet but I can have my hand cut off if they sound bad.

http://www.jblpro.com/BackOffice/Pro...BL.LSR6332.pdf
JBL :: Product

Please also read one of his articules on audio reproduction "Science in the service of art".
http://www.theaudiocritic.com/back_i...ritic_28_r.pdf

I cant agree again that measurements are not important for listening. I assure you that all speaker manufactures do measure their speakers but few are willing to show what is the outcome of these measurements. If they dont there is something wrong with the design what measurements would cleary indicate. I agree you still need to listen to the speakers you are willing to buy but at least I would know where to start from.
Again nobody has said measurements are not important - they are important, incredibly so, but not for comparing speaker A measured by Person Z in Room Y after 5 hours of having audio passed through it against speaker B measured by Robot G in room H which has just come out of a stone-cold storage room. This would tell very little if anything useful at all.

I've heard the LSR 6332 (or at least something which looked exactly like them from JBL) and they are very, very good IMO. However I have heard a number of really rather awful JBL speakers which bear no resemblance to each other in terms of sound or basic design.

All the ATC speakers I have heard are extremely good and share a huge amount with each other sonically. There are a few differences here and there (SCM25s don't quite have the lean-ness of the SCM50, the older 'entry' range aren't quite as refined as the larger models at he top end etc), but it's pretty amazing that a tiny standpoint like the SCM7 can sound so similar to a massive speaker like the SCM150, let alone bear any resemblance at all.

Quote:
Originally Posted by dziemian View Post
I think there is one main diffrence between many commercial manufacturers and DIY builders. In DIY community if you claim you have superior design you have to prove it with your measurement before anyone wants to listen to them. Apparently many producers either think we are too stupid to understand measurements or they want to hide some imperfections. You can always write a fairy tale about problems with consistency of the measurements but some other producers somehow still measure, publish and explain measurment conditions on their websites.
Have you ever actually measured a speaker's behaviour in an anechoic environment? Or plotted a specially-averaged response? It isn't a 'fairy-tale' when you experience it first hand.

Most people do not understand the measuring process, or even the results of the measuring process enough to use the information correctly, or indeed know when to disregard the measurements.

Quote:
Originally Posted by dziemian View Post
It is up to me if I believe in them or not and they can be always verified by the third party.
It is also up to the manufacturers if they want to expose their products to mis-interpretation and completely nonsensical/useless comparisons. Not publishing measurements is the best way to do this.

Quote:
Originally Posted by dziemian View Post
For example some DIY designs from Dr Linkwitz which are considered as excellent sounding. Just see how much information you can read about these designs.

Linkwitz Lab - Loudspeaker Design
[/QUOTE]

I've not heard any Linkwitz-Lab stuff, and while the theory behind true fig-8 speakers is interesting, he publishes no information about amplitude/power linearity or harmonic distortion. I wouldn't let me put that off hearing a pair though, even if other (electrostatic) fig-8 speakers have been a nightmare to integrate into rooms in my extremely limited experience with them.


There is always a reason behind different manufacturer's design choices, it's always down to compromise. But many manufacturers know they can't release measurements into the wild without also incurring the wrath of mis-interpreted 'facts' and speculation on web forums (ahem).

Try the speakers out, compare them directly against other speakers (same room, same electronics, same signals) and see how it pans out. That's the only way to really compare the pros & cons of different speakers.
Old 24th December 2013
  #19
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Have you actually used the Linkwitz design? First while I do love dipoles and bipoles, mixing on them is another matter.
The ATC SCM50 is a very simple and straight forward design.
No speaker has a uniform dispersion through its entire frequency range, the baffle enclosure prevents it.

I don't know of a single DIY design that has comprehensive measurements I would trust for comparison, the room/ standards are just not uniform enough!

The funny thing is most in the DIY community put ATCs designs on a pedestal and the major complaint is the price!
And remember the guys at Madisound and Solen where pretty much all clients of mine!
Old 24th December 2013
  #20
Here for the gear
 

I havent said Linkwitz design is good for studio work. I was just an example that even some DIY projects are better described and measured then ATC products.

DIY community likes to copy ATC SCM50 and higher, but on a real pedestal there is only their SM75-150 midrange. It is used in many other designs too.


Anyway, thank you guys for your interesting comments. That is why I like this forum so much.
Old 24th December 2013
  #21
Lives for gear
 
AlexK's Avatar
 

Glad to hear!

ATC make some other pretty amazing drivers too - the one in the SCM19/20 is pretty spectacular - grafted-on midrange dome, amazing amount of linear travel and very low distortion. I'm always blown away by how loud SCM20s will go and still show no signs of stress. The mid bass driver in the SCM7 is IMO pretty incredible too, again for the same reasons as the SCM20. In fact all of their bass drivers are pretty special. Their new tweeters are going to cause a few stirs too I think - double spider, very small coil-gap, very high power handling, very low distortion.
Old 24th December 2013
  #22
Lives for gear
 

Dziemian:

It is strange to me that you seem not to trust ATC. Usually its the reverse, the most skeptical of the speaker world are drawn to ATC over its firm grounding in science. I understand not trusting large, rich businesses, but ATC is not one of those. The concept of "acoustic engineers" is a serious thing for them. So if you like the science of loudspeakers, here is ATC's look behind the curtain:

http://www.transaudiogroup.com/uploa...Whitepaper.pdf


Brad
Old 22nd January 2014
  #23
Gear Head
 

Quote:
Originally Posted by Hjelmevold View Post
Here are some measurement results for the ATC SCM25A Pro, provided by Resolution:
http://resolution.nodecube.net/produ...M25A%20Pro.pdf
Summary: Relatively flat frequency response, very good waterfall plot, but a poor step response with some time-smearing between the drivers.
Glad you like the 25s, I own 50s.

I saw that Resolution review a long time ago. According to what Linkwitz says here Frontiers I thought Resolution misinterpreted their own step response measurement - and it's doubly unfortunate that this formed part of their summary.

Actually if you read the Linkwitz link, he explains why for 3 ways the step response is easy to mis-read and he gives an example of an audiophile magazine (not Resolution I'm guessing) doing that also.

Quote:
Originally Posted by AlexK View Post
The dispersion of ATC speakers gradually narrows a little as you go from low to high frequency, although they are still 'wide' even near the top of the tweeter's passband. This is important, a gradual transition from wide to slightly-narrow(er) - this is what the OP is referring to. Omnidirectional broadband speakers don't exist.
Bingo. Controlled narrowing is a very valid approach, you could even argue it's an inherent part of the closed baffle paradigm given bass starts off monopole. What's important is to avoid big discontinuities and this is where many closed baffle speakers aren't as good.

Open baffle designs offer a different paradigm obviously.

Quote:
Originally Posted by dziemian View Post
diffraction on straight edges (you need always grills on), bad center to center distance between tweeter and mids, badly implemented tweeter (in my opinion). I know there are always trade-offs but they have no standard at all in their speakers. Some speakers are rectangular (SCM50, SCM20), the other are rounded (SCM70, SCM20 pro), some like SCM50 have their tweter and mids off-center for dealing with diffraction, the others basically the same like SCM70 have them on center.
As said, the SCM70 was an unusual (no longer available) design.

The pro actives have rounded edges and quadrant frames can be supplied for the domestic actives to give rounded edges without grilles (I use these).

The vertical distance between tweeter and mid is partly due to the massive construction of the 3 inch dome assembly, this has its own rewards.

The horizontal offset between mid+tweeter and bass is inherited from the pro models that can be used in landscape format and therefore need room for the optional tweeter placement. Clearly, horizontal offset between tweeter and mid is critical and always zero. But anyway, it does confer advantages with edge diffraction occuring at different moments left and right for mid+tweeter units - obviously there is going to be a very slight phase offset between bass and mid but nothing significant. But the EL150 edge diffraction is handled so well that the pros/cons stack differently in that design.

Pretty much every element of the ATC design is that way for a particular reason. Personally, the more I've poked and delved the more this has become clear.

BTW I am not an ATC "fan boy" ... if we're talking actives, I happen to think the Linkwitz Orion, and various models from PMC and Meridian, can sound fabulous. Nothing against them at all, fine choices.
Old 22nd January 2014
  #24
Lives for gear
Quote:
Originally Posted by dziemian View Post
I believe that speakers which perform well in terms of on and off-axis response, polar plot etc are essential.
Well you have the Gedlee speaker on your list there so it sounds like you already know what to do...any of the seos stuff on diysoundgroup.com.

The *next* step in speaker design is minimum diffraction constant directivity, but it's going to take a while for it to hit the pro market because people here tend to have an irrational fear of "horns" (yet things like the big strauss are acceptable ). Floyd Toole's work is really showing up in the new JBL stuff, so it might not be that long.

I have the auto-tech SEOS-24 with radian 951's with truextent beryllium phrams, mind bogglingly good, Quad ESL clarity with perfect directivity and limitless dynamics...Whenever all this stuff does start to hit the pro studio market ATC will have to start playing catchup.
Old 22nd January 2014
  #25
Here for the gear
 

Well, I am sceptical about any promotional materials which are not supported by true measurements. There is a hype in audio world right now and people make a load of money on stupidity and naivete. I really want to listen to ATC stuff for longer at home so I will try to mix diffrent approaches now. I will use SB75-234SL woofer and SM75-150S midrange driver from ATC's SCM50 but change a tweeter to Transducer Lab N26C with one of David Pellegrene's waveguides. The waveguide will allow me to match the polar response of the midrange. I will also move the crossover point lower to match the C-2-C distance between T&M. All in active setup controlled by DEQX and 6-channel amp. The box made of MDF with rounded edges cut in CNC, all measured in REW. I have most of the items I need but ATC's midranges and waveguides. And I need time to finish it as it is just a hobby. I suppose this setup should calm my nerves. Then I need to find sb with original SCM50 to compare If it sounds bad I will rip it apart and resell the parts.

Seos stuff is good and probably I will check it out once I am done with ATC. I am more and more convinced that the only good part of ATC speakers is their midrange unit. The box design is passe. There are far better tweeters on the market althought I have not heard their new tweeter yet. I cant say anything bad about SL woofers but I belive Acoustic Elegance woofers are equally good or better and much cheaper.

So if I was supposed to build a copy of SCM50 I would do it diffrently. If I was supposed to buy a new pair I would buy sth else (Gedlee, SEOS, JBL LSR). The advantage of SCM50 is that a load of music has been mixed on these and it would be smart to reproduce the same sound from the recording studio at home using the same speakers (and forget about room input)
Old 22nd January 2014
  #26
Lives for gear
Sounds like a good project-

I think it is worth the extra C2C gap to match directivity, especially in the horizontal plane, and especially if you have DSP. Even if it loses directivity rather high. The SM75-150S is a very good driver. You may also want to look at the acoustic elegance (lamda) drivers, not that the ATC woofer isn't good, but there is a lot more competition for them in that arena than the soft dome mids.
Old 3rd February 2014
  #27
Gear Head
 

Quote:
Originally Posted by dziemian View Post
The box design is passe.
A few points about ATC cabinets (larger models available as actives) that aren't often acknowledged:
- of course, internally each driver has its own cabinet volume
- the cabinets are massive in construction. A PASSIVE 50 weighs >41kg.
- the cabinets are rounded for the pro versions and the domestic grilles contain the rounding elements for the domestic versions. Quadrant frames are available for domestic users wanting the rounding elements without grilles. So in use they are rounded boxes despite all those images on Google!
- they are NOT a standard reflex ported design. Roll off is 3rd order, not the standard ported 4th order; this unusual quality is down to the cabinet design (because ATC don't use EQ/notch filters in their active crossovers, and the same roll off applies for the passive versions).

I hope this gives you new-found appreciation for the (larger) ATC cabinets.

Regards, Darren
Old 3rd February 2014
  #28
Gear Addict
I've been using my ears to measure the performance of the scm50s. They tell me the monitors are fantastic.
Old 3rd February 2014
  #29
Righto!

Quote:
Originally Posted by Citrus Fresh View Post
I've been using my ears to measure the performance of the scm50s. They tell me the monitors are fantastic.
+1 Using my superior patent passive ear enhancers, designed specifically to make smaller ATC SCM models sound just as powerful as their larger cousins:

at a fraction of the cost I might add.
I am able to clearly discern that those that measured the ATC's in article in the OP's post had not measured them in the OP's control room sitting where he usually sits.
So If the OP can afford to buy ATC monitors of commensurate size for his control room? he should as quickly as possible and then he will have a far better chance of getting used to them in his control room, before it really matters, now we have that sorted, he can save up for all the rest of the newfangled fashionable active protagonists he has room for, for AB testing.
Old 9th February 2014
  #30
Here for the gear
 

Sorry, half of my friends who "measured their speakers with their ears" could not hear 6db dips or peaks on the response.

I think, this article is worth reading regarding the subject. It is written by Sean Olive, the current President of the Audio Engineering Society.

What Loudspeaker Specifications Are Relevant to Sound Quality?

Audio Musings by Sean Olive: What Loudspeaker Specifications Are Relevant to Sound Quality?
Topic:
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