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ATC speakers / Monitors

Avp1

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then it still don't justify their still expensive, lesser siblings in home audio which is not bad, but not up to competition in the metrics
You need to use them properly. Small speakers are designed for listener at 3-4 feet. Put them on your computer table and you will do it right.
For in-room use SCM40 is a bottom model and you usually need 100 or 150 for real size room at home. If you accept this, you understand the logic behind ATC design.
 

Frgirard

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You need to use them properly. Small speakers are designed for listener at 3-4 feet. Put them on your computer table and you will do it right.
For in-room use SCM40 is a bottom model and you usually need 100 or 150 for real size room at home. If you accept this, you understand the logic behind ATC design.
Northward use atc acm40a in his loft.

Isn't it Thomas?
 

Torbachkristensen

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May I suggest not to generalize on the >37000 members based on a few unpleasant interactions / threads? There are a lot of both very knowledgeable and kind people here, and IME a lot of opportunities to learn from them. I personally hope you and others stay and engage / contribute - even if you disagree! :)

Let me start by saying that I hope you don't see this post as combative - I will just try to clarify a few concepts that I feel might be misunderstood; I hope you may find it useful!


I wonder why you put the word anechoic under quotation marks? Anechoic stands to mean "without reflections", but doesn't really specify how this is achieved:
  • Klippel NFS achieves this by measuring loudspeaker output in the relative nearfield and then applying clever mathematics to remove reflections.
  • Another way to do it is to measure the loudspeaker in a calibrated anechoic chamber (which are never truly anechoic in the low bass, BTW - this is why they are calibrated) out of its acoustic nearfield.
  • A third way is to use the quasi-anechoic methods (appropriately time-gating the HF measurement and splicing with ground-plane or baffle-step-compensated nearfield LF measurements to get the full-range anechoic response).
All three approaches result in anechoic measurements (since in all cases the effect of reflections is removed) which, if done correctly, give the same qualitative response and are very comparable. The difference is usually just resolution - NFS having the highest resolution, quasi-anechoic usually the lowest.
If you are interested, this amazing web resource by @pierre contains measurements made by various methods, and you can even compare them directly.

Regarding the estimated in-room response / PIR, may I ask why do you think it is 'ridiculous'? I ask because I notice people sometimes mistakenly assume the PIR is supposed to show what we hear at the listening position. If you read the research it will be clear that PIR is instead meant to represent what would be measured at the listening position (but only above the room's transition frequency, as it doesn't account for SBIR, room size/treatment and placement). Below the transition frequency room modes and loudspeaker / listener positioning take control and PIR isn't meant to model that - which is also clear from the research.
In my experience doing loudspeaker measurements PIR has proven really successful in predicting how the actual in-room measured response looks like, see e.g. here for some examples.
Research also implies that what we hear is definitely not the same as what we measure in-room - we hear more of the loudspeaker direct sound (i.e. its anechoic response) in the mid and high frequencies than what is suggested by the in-room steady-state response.

Related to this, unfortunately there is a common misconception among hobbyist that good sound can be achieved by EQ-ing any loudspeaker's in-room measured response to a specific target (e.g. the Harman target). If you read dr. Toole's book you will see this is never claimed (see also this post for a reference) - it is actually the other way around - in-room measurements of various good loudspeakers result in a curve resembling what is commonly called the "Harman target". So it is not really a target for EQ - it is the expected result when using good loudspeakers.
EQ still has its place in achieving good reproduced sound - it helps to fix certain issues in the bass (mainly reducing peaks / resonances) and it can also be used to improve tonality of loudspeakers that otherwise have even / good directivity.
Blindly EQ-ing towards a tidy-looking full-range in-room response can definitely make things sound worse, and this is IME actually well understood by many people on this forum!


I don't know which specific M2 system you are referring to (I must admit I didn't follow all posts), but please note that in the low frequencies humans hear the combination of the room and loudspeaker response, and the in-room steady-state response is indeed instructive to what is heard in that frequency range. Given that the loudspeaker-room system is largely linear and time invariant (LTI), Fourier transform allows us to go from time to the frequency domain (and vice-versa). A resonance in the frequency domain means ringing in the time domain - so addressing the resonance (by room treatment/layout, multiple subwoofers arrays and/or EQ) also addresses the ringing / reduces decay-time at the problematic frequency. I.e. achieving a close to ideal FR in the bass means also no ringing in the time domain. What multiple subwoofers bring to the table is a chance to fill dips in the bass response and make the response more similar across multiple seats - but not necessarily flat response (at least not without EQ).
In short: there may be more than one road to Rome. :)

Lastly, in case you haven't done so already, I'd really recommend to give a chance to dr. Toole's "Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Room, 3rd edition" book. IMHO it is a really good overview of the field, even if you disagree with some conclusions. There's much more insights, structured clarifications, arguments and references there than one can find in a few forum posts. :)
Thanx for the well thought out and intelligent post - wish you would have been here sooner :)

Take a look through the thread, and I think you will find that Northwards and I have made more or less exactly the same points and arguments, at different times independent of one another. We have almost the exact same views on what makes a good system. The common perception here seems to be that speaker sound quality can be defined solely by measurements, and generally the limits of what we can measure are disregarded. My view is that quality speakers, quality cabinet and quality room all needs to come together with the correct compromises for the situation/listener. And different speakers adhere to different compromises.

I have been through numerous books including Dr. Toole taking my Masters Degree in Audio Engineering, but I find he is mostly misinterpreted and quoted outnof context throughout this thread. Why I think the estimated in room response is generally irrelevant, is because so much of what makes up the perceived sound quality is 300hz and below. Uneven response in 20-300hz can make any speaker sound terrible, while anomalies higher up in the spectrum is more forgiving - largely due to less inherent problems in the time domain. An as you mention, we start to hear the direct response when moving up the spectrum. All I need with regards to anechoic FR is a fairly flat response, without obvious resonanses - beyond that I use my ears and try to validate with measurements. “Anechoic” in quotation marks was just a comment on the amount of anechoic data being posted, where I don’t find it quite as important in actual roomdesign and listening experience. I was not questioning the validity of the Klippel Nearfield Scanner.

I encourage an exchange of views as long as it is discussed with common respect, however EQ’ing and adding subs to alleviate room modes is not a good solution IME, it does not come close to well controlled decay times, when talking about actual listening experience. “I.e. achieving a close to ideal FR in the bass means also no ringing in the time domain” - this statement IMO is not correct. Attenuated room modes are not corrected, they are simply… well, attenuated. The decay time is still there, and can most definitely be heard.

+ in a room with even decay, FR becomes less critical and can be easier adjusted to taste/target - unfortunately it doesn’t work the other way around.
 
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Frgirard

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In the hifi world the decay is a black hole. In bass frequencies it's the first parameter to take care.
In mid and high frequency, lower is the decay, greater is the detail of the reproduction.
In audiovisual technician training, they learn that the decay and the perceived and measured sound volume are closely linked. You want detailed reproduction, use the potentiometer but with 0.5ms in the mids it will scream.
 

dominikz

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Thanx for the well thought out and intelligent post - wish you would have been here sooner :)

Take a look through the thread, and I think you will find that Northwards and I have made more or less exactly the same points and arguments, at different times independent of one another. We have almost the exact same views on what makes a good system. The common perception here seems to be that speaker sound quality can be defined solely by measurements, and generally the limits of what we can measure are disregarded. My view is that quality speakers, quality cabinet and quality room all needs to come together with the correct compromises for the situation/listener. And different speakers adhere to different compromises.

I have been through numerous books including Dr. Toole taking my Masters Degree in Audio Engineering, but I find he is mostly misinterpreted and quoted outnof context throughout this thread. Why I think the estimated in room response is generally irrelevant, is because so much of what makes up the perceived sound quality is 300hz and below. Uneven response in 20-300hz can make any speaker sound terrible, while anomalies higher up in the spectrum is more forgiving - largely due to less inherent problems in the time domain. An as you mention, we start to hear the direct response when moving up the spectrum. All I need with regards to anechoic FR is a fairly flat response, without obvious resonanses - beyond that I use my ears and try to validate with measurements. “Anechoic” in quotation marks was just a comment on the amount of anechoic data being posted, where I don’t find it quite as important in actual roomdesign and listening experience. I was not questioning the validity of the Klippel Nearfield Scanner.

I encourage an exchange of views as long as it is discussed with common respect, however EQ’ing and adding subs to alleviate room modes is not a good solution IME, it does not come close to well controlled decay times, when talking about actual listening experience. “I.e. achieving a close to ideal FR in the bass means also no ringing in the time domain” - this statement IMO is not correct. Attenuated room modes are not corrected, they are simply… well, attenuated. The decay time is still there, and can most definitely be heard.

+ in a room with even decay, FR becomes less critical and can be easier adjusted to taste/target - unfortunately it doesn’t work the other way around.
In general I find that online written discussions can easily lead to misunderstandings which sometimes spiral into unnecessary conflicts (here as much as anywhere) - I suppose it is an unfortunate result of lack of non-verbal feedback (and probably anonymity). I theorize that the mechanisms are somewhat similar to those behind the "road rage" phenomenon. :)

Back on topic, just to address a few statements:
The common perception here seems to be that speaker sound quality can be defined solely by measurements, and generally the limits of what we can measure are disregarded.
TBH I don't see it really that way. My take is that the general community here demands data / evidence / references when controversial audibility claims are made, versus anecdotes or appeals to authority that most of us are used to using in our day-to-day. IMHO it is a laudable approach, but of course it is at times misused, misinterpreted, and most definitely takes time to adjust to - if it is even possible for a human being to think that way 100%!

Uneven response in 20-300hz can make any speaker sound terrible, while anomalies higher up in the spectrum is more forgiving - largely due to less inherent problems in the time domain. An as you mention, we start to hear the direct response when moving up the spectrum. All I need with regards to anechoic FR is a fairly flat response, without obvious resonanses - beyond that I use my ears and try to validate with measurements.
Largely I agree. I'd perhaps even go as far as to say that I feel people make too much of the audible differences between similarly well-measuring loudspeakers. Sure, they sound different when compared side by side, but it is in many cases just a matter of sounding slightly different (rather than better or worse), and once you make your pick any differences are surely very quickly masked by perceptual adaptation. IMHO, IME, etc... :)
Fixing reproduction in the bass range is definitely critical and can completely ruin any speaker - agreed! Perhaps that is why some people like very bass-limited loudspeakers! :D

“I.e. achieving a close to ideal FR in the bass means also no ringing in the time domain” - this statement IMO is not correct. Attenuated room modes are not corrected, they are simply… well, attenuated. The decay time is still there, and can most definitely be heard.
Sure, I guess it depends how precise you want the statement to be. :) EQ can of course only solve audibility of resonances for a limited listening area only, and the room modes themselves still exist and could be causing audible resonances elsewhere in the room. Similarly, this solution is only valid when using the system with EQ applied - any other sound sources in the room will still trigger the unattenuated room resonances. Lastly, PEQ usually cannot solve deep nulls in the response (luckily these are less audible). It is a cheap, no-footprint and very effective approach, though! :D

Multiple subwoofers allow you to make the resonance pattern more similar across a wider area, meaning that the same PEQ can fix the response for more of the room. They also help address nulls. It still doesn't solve the physical problem - but it can solve the audible issue in the reproduction system.

Please note that room treatment also doesn't completely eliminate resonances (even anechoic chambers show traces of room modes). Appropriate room treatment however has a significant advantage of addressing the resonances / nulls equally in the whole room and for all sound sources. It is also usually very expensive and takes a lot of space to address resonances in the very low frequencies. Even with treatment EQ and multiple subs can still be beneficial, though!

Of course I'm not trying to say that PEQ and multiple subwoofers obsolete room treatment or anything like that - just trying to highlight some of the considerations regarding each approach. I'm sure there are very good sounding systems engineered in various ways!

Lastly I refer to the chapter 8.2.4 (pages 232-234) of dr. Toole's "Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Room, 3rd edition" for a better explanation of using PEQ for fixing bass (especially figure 8.12 for a nice example of how sufficiently precise subtractive PEQ impacts ringing in the time domain). Chapters 4.6.2 and 4.6.3 also provide a nice refresher of how high-Q spectral resonances (or their absence) are tied to ringing in the time domain (or its absence).
 
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Torbachkristensen

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In general I find that online written discussions can easily lead to misunderstandings which sometimes spiral into unnecessary conflicts (here as much as anywhere) - I suppose it is an unfortunate result of lack of non-verbal feedback (and probably anonymity). I theorize that the mechanisms are somewhat similar to those behind the "road rage" phenomenon. :)

Back on topic, just to address a few statements:

TBH I don't see it really that way. My take is that the general community here demands data / evidence / references when controversial audibility claims are made, versus anecdotes or appeals to authority that most of us are used to using in our day-to-day. IMHO it is a laudable approach, but of course it is at times misused, misinterpreted, and most definitely takes time to adjust to - if it is even possible for a human being to think that way 100%!


Largely I agree. I'd perhaps even go as far as to say that I feel people make too much of the audible differences between similarly well-measuring loudspeakers. Sure, they sound different when compared side by side, but it is in many cases just a matter of sounding slightly different (rather than better or worse), and once you make your pick any differences are surely very quickly masked by perceptual adaptation. IMHO, IME, etc... :)
Fixing reproduction in the bass range is definitely critical and can completely ruin any speaker - agreed! Perhaps that is why some people like very bass-limited loudspeakers! :D


Sure, I guess it depends how precise you want the statement to be. :) EQ can of course only solve audibility of resonances for a limited listening area only, and the room modes themselves still exist and could be causing audible resonances elsewhere in the room. Similarly, this solution is only valid when using the system with EQ applied - any other sound sources in the room will still trigger the unattenuated room resonances. Lastly, PEQ usually cannot solve deep nulls in the response (luckily these are less audible). It is a cheap, no-footprint and very effective approach, though! :D

Multiple subwoofers allow you to make the resonance pattern more similar across a wider area, meaning that the same PEQ can fix the response for more of the room. They also help address nulls. It still doesn't solve the physical problem - but it can solve the audible issue in the reproduction system.

Please note that room treatment also doesn't completely eliminate resonances (even anechoic chambers show traces of room modes). Appropriate room treatment however has a significant advantage of addressing the resonances / nulls equally in the whole room and for all sound sources. It is also usually very expensive and takes a lot of space to address resonances in the very low frequencies. Even with treatment EQ and multiple subs can still be beneficial, though!

Of course I'm not trying to say that PEQ and multiple subwoofers obsolete room treatment or anything like that - just trying to highlight some of the considerations regarding each approach. I'm sure there are very good sounding systems engineered in various ways!

Lastly I refer to the chapter 8.2.4 (pages 232-234) of dr. Toole's "Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Room, 3rd edition" for a better explanation of using PEQ for fixing bass (especially figure 8.12 for a nice example of how sufficiently precise subtractive PEQ impacts ringing in the time domain). Chapters 4.6.2 and 4.6.3 also provide a nice refresher of how high-Q spectral resonances (or their absence) are tied to ringing in the time domain (or its absence).
I understand the compromises of course. But it is worth remembering that narrow bandwidth PEQ introduces significant amounts of either A) Pre-ringing with FIR filters B) Phase Shift with IIR Filters. B) is also valid for subwoofer additions. Both compromises that room treatment does not introduce :)

And what we want is not anechoic decay time, but even decay
 

dominikz

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B) Phase Shift with IIR Filters.
Some might view that as 'phase correction' :p But I do believe we are roughly in agreement.
Just to add that audibility of many time-domain and phase phenomena is still quite controversial whereas audibility of various spectral magnitude characteristics is well established.
 

YSC

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I understand the compromises of course. But it is worth remembering that narrow bandwidth PEQ introduces significant amounts of either A) Pre-ringing with FIR filters B) Phase Shift with IIR Filters. B) is also valid for subwoofer additions. Both compromises that room treatment does not introduce :)

And what we want is not anechoic decay time, but even decay
Sure for that part, I wholewheat agree on the importance of room treatment for it to be a best way to option best sound possible, but then it’s off topic on atc speaker which is the center of all debates and argue in this thread
 

Northward

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Have proofs of your tells? Proof =measurements.
Conversations are good for audiophiles. Measurements are better to engineers.

I see you have that you have your guard dogs like on Gearspace.

You're an engineer?

Then let's do something interesting: if you take the time to answer (quickly) these questions I'll share some data:

- In a hemi-anechoic space, with the mid-dome of an ATC 110 at 127cm from the floor (for the sake of simplifying the problem, we consider it to be perfectly reflective / infinite impedance) - at what frequencies should we expect to see the floor effect appear if the measurement mic (aligned at mid dome height on axis) is 1m, 2.4m and 3.6m away from the speaker?
- How is the floor effect Q expected to behave when measuring a dual woofer ATC 110 speaker vs a single woofer ATC 50 speaker?
- How much of a peak LF boost should we expect from in-wall mounting a full range ATC 110 speaker in theory and in real life? At what frequency should we be expecting to see the start of the LF rise? (Infinite front wall impedance.)
- What is the typical expected delta in distorsion levels between coupled in-wall systems and (properly) decoupled in-wall systems? What happens to distorsion levels in the area around the decoupling system's natural frequency f(n)? And above sqrt(2)*f(n)?
- What's "minimum phase"?
- When talking about fully anechoic chamber measurements of loudspeakers, what simple acoustic law / tool can be used to check the actual cut-off frequency of the chamber that is used?
- What happens to the speed of sound when it enters a piece of rockwool?

All these things have something to do with how you read a FR, ETC, distorsion or Waterfall measurement properly.
 

Northward

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Can you share some measurements of your rooms?
Keith
Answer these questions above too and I will share some data yes. Otherwise I am just not willing to give any time and energy dealing with armchair quarterbacks. I'm done with deaf conversations and constant data misinterpretation on fora. It is a real issue.

I want to know the person requesting and reading the data has some form of understanding of basic acoustic principles.

Though I've shared some data before...It's out there.
 

AdamG

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Answer these questions above too and I will share some data yes. Otherwise I am just not willing to give any time and energy dealing with armchair quarterbacks. I'm done with deaf conversations and constant data misinterpretation on fora. It is a real issue.

I want to know the person requesting and reading the data has some form of understanding of basic acoustic principles.

Though I've shared some data before...It's out there.
Post edited as I was too quick to respond jumping to an incorrect assumption. I failed to read back far enough into this thread. My apologies. Please disregard.
 
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Purité Audio

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Aren’t the measuremeets that special?
Is that why you aren’t keen to share?
Keith
 

turnip_up

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Sure for that part, I wholewheat agree on the importance of room treatment for it to be a best way to option best sound possible, but then it’s off topic on atc speaker which is the center of all debates and argue in this thread

Nobody listens to speakers in an anechoic chamber. The in-room response is really the only thing that matters... because that is where sound goes into earholes.

Unless of course, this forum has absolutely nothing to do with listening to speakers.
 

thewas

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Nobody listens to speakers in an anechoic chamber. The in-room response is really the only thing that matters... because that is where sound goes into earholes.

Unless of course, this forum has absolutely nothing to do with listening to speakers.
That is not correct as our hearing is more complex than a measured in-room response at the listening position, for example above transition frequency the perceived tonality is mainly influenced by the direct sound. That's why also just equalising some loudspeakers to a desired LP target isn't usually successful, see the first link in my signature about more details about it.
 

Northward

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Aren’t the measuremeets that special?
Is that why you aren’t keen to share?
Keith
I'm not keen to share because the measurements of a FTB room aren't trivial to interprete since those spaces are dual (hence there are two types of measurements made: speakers to engineer/room response and room to engineer response also known as "self-noises cues environmental response".)

Both aspects are fundamental to the performance and reliable translation of the work. Those spaces are a system of systems. It's very far from "how flat is the FR".

Honestly, seeing the kind of misinterpretations of "normal" data I witness on a regular basis, I can't see how sharing that data with users that come across as only out for blood but that don't necessarily have the tools or background information/ knowledge to understand what they're actually looking at is going to be a pleasant conversation for me.

This "death to expertise" mentality over the internuts, where it's more about some users with no actual real world experience or background doing all they can to prove the experts wrong online and get their ego boost (often relying on data they did not understand or claiming impossible / unrealistic results) rather than a constructive, open conversation.

I have zero time and energy to give to that.

Irl, this seldom happens. So I much, much prefer geeking out about that stuff around a drink on a sunny terrace, or during a hang at the office / studio or construction site.

I share data, just not in all circumstances or to just anybody who asks.
 

Torbachkristensen

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That is not correct as our hearing is more complex than a measured in-room response at the listening position, for example above transition frequency the perceived tonality is mainly influenced by the direct sound.
To be fair, the post you commented on says nothing about measured response or even LP; just says in-room response. Which is not really contradictory to your point.

That's why also just equalising some loudspeakers to a desired LP target isn't usually successful, see the first link in my signature about more details about it.

Which again adds to the point made earlier about the pretty useless LP perfection of a highly tweaked JBL M2 system, with really nothing else to show but a flat FR. It says little about the actual sound in the room.
 
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thewas

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To be fair, the post you commented on says nothing about measured response or even LP; just says in-room response. Which is not really contradictory to your point.
As you know typical in room measurements tell very few about important loudspeaker qualities like directivity, as you need quite more effort for that.
 

thewas

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I have really no idea what point you are trying to make. Sorry :)
That typical in-room measurements cannot tell much about several important qualities of loudspeakers, there is a reason why people spend high efforts and costs like large anechoic chambers or Klippel NFS to measure them. :)
 
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