Evidence-based Speaker Designs

[direstraitsfan98]

I can't find measurements for ATC SCM50 100 OR 150 anywhere.

 

[tuga]

I can't find measurements for ATC SCM50 100 OR 150 anywhere.

SM75-150 Midrange

http://www.troelsgravesen.dk/ATC-SM75-150.htm

http://zaphaudio.com/blog.html


Speakers

https://www.hifinews.com/content/atc-scm100se-loudspeaker-lab-report

 

[direstraitsfan98]

Those don't look like the speakers I was talking about. Those look like floor standers. Not sure if it matters. Also I don't know if it matters in regards to if the active vs passive would measure different but those are the passives in that particular review I think. edit. nevermind, I guess the right speaker in that one is the active version. I can't read that language so I had to take a closer look. It looks like there's a 4 or 6dB dip in the crossover of the midrange driver at 3.5kHZ which maybe is what ilkness was talking about. I've never really understood how graphs work even though Amir includes them in his speaker reviews. I guess that the dip at 3.5kHz is bad? I know my speakers have a small dip at the crossover point at 700hz but apparently that is less of an issue because it's at a lower frequency.

 

[tuga]

I guess that the dip at 3.5kHz is bad?

I guess you could say it is bad since it looks like it's caused by the breakup resonance of the mid dome.

 

[Ilkless]

Those don't look like the speakers I was talking about. Those look like floor standers. Not sure if it matters. Also I don't know if it matters in regards to if the active vs passive would measure different but those are the passives in that particular review I think. edit. nevermind, I guess the right speaker in that one is the active version. I can't read that language so I had to take a closer look. It looks like there's a 4 or 6dB dip in the crossover of the midrange driver at 3.5kHZ which maybe is what ilkness was talking about. I've never really understood how graphs work even though Amir includes them in his speaker reviews. I guess that the dip at 3.5kHz is bad? I know my speakers have a small dip at the crossover point at 700hz but apparently that is less of an issue because it's at a lower frequency.

CtC = centre to centre spacing.

Because of that old-fashioned motor design, it has a huge, bulky flange/driver frame that increases CtC spacing needed. For a given crossover frequency, larger CtC = worse vertical performance due to lobing. Now this driver is well-behaved to a pretty high frequency. But all that performance is wasted because you have to cross it lower than that (thus defeating the point of the expensive driver), or start compromising vertical performance and make it very finicky to listening height.

Hence the comparison to Neumann's mid dome, which has almost JBL M2 level of measured headroom and distortion in a much more compact frame and vastly better directivity control than that ATC paperweight. I frankly don't rank them much higher than PMC or Harbeth.

 

[Purité Audio]

I had the active 50s here, after everything I had read ( mid range dome blah blah) they were disappointing compared to contemporary designs.
Not unlike the BBC designs and Quad for that matter which must have been exceptional fifty years ago.
Keith

 

[direstraitsfan98]

I have to correct some comments I made about the scm50 measurements from what tuga posted. It looks like it’s +/-2dB from 60-20kHz, not 4-6dB at least according to stereoplay themselves.

And thanks for your subjective opinion Keith but I have to take your comments with a grain of salt because you’re a dealer. I was about to say you don’t represent atc so of course you wouldn’t feel obligated to praise a brand you don’t carry but you actually do carry atc since I visited your website to check.

You have the scm50 you mentioned listed on your site along with some words I noticed “'I have the simplest of tastes I am always satisfied with the best. ATC have and continue to make the very best loudspeakers available, the complete range of ATC loudspeakers and electronics are available from Purité Audio.”

Outdated text in your site from before you stated carrying Kii and Grimm speakers? We know you prefer DSP based systems. So I guess it would make sense you prefer those brands. Interesting how people can label a brand as “the best” but a few short years later the latest and greatest thing overtakes it completely...

Not sure what to think, I will have to do a lot more research and of course hear the speakers myself. One thing that I wonder about atc and why someone might not be enamoured with their sound is the fact that apparently atc needs placement in treated rooms to sound their best and also I’ve heard reports at least regarding the scm150 that they sound rather unengaging at low volumes. Could anyone offer a suggestion why that may be?

 

[Purité Audio]

Oscar Wilde said that not me, but you are quite right to listen to everything yourself in your own room.
I would just point you towards the objective measureable differences between ATC and say the 8Cs.
ATC do sound great in a fully treated studio but then so do most loudspeakers.
Keith

 

[tuga]

Not sure what to think, I will have to do a lot more research and of course hear the speakers myself. One thing that I wonder about atc and why someone might not be enamoured with their sound is the fact that apparently atc needs placement in treated rooms to sound their best and also I’ve heard reports at least regarding the scm150 that they sound rather unengaging at low volumes. Could anyone offer a suggestion why that may be?

Inadequate amplification perhaps?
The SCM150s are too expensive to buy blind, and too bulky to setup only to find that they're not what you are looking for.

I just ignore comments/subjective reports, the critics', the owners', reatilers' and anyone else's.
It's my rule #1 (rule #2 is never to replace a piece of equipment without having identifyied its flaws, pinpointed their probable causes and shortlisted potencial replacements which deal with those problems without creating new ones).

 

[Ilkless]

I had the active 50s here, after everything I had read ( mid range dome blah blah) they were disappointing compared to contemporary designs.
Not unlike the BBC designs and Quad for that matter which must have been exceptional fifty years ago.
Keith

The British monitor cult of personality is one of the strongest in the industry. They all have a superficial commitment to engineering, yet release merely incremental improvements on rustic designs under an outdated engineering paradigm. Slightly better cone material here, more copper in the motor there. No thought given to the loudspeaker as a system, how to improve the system's radiation, to reduce the total colouration of the system. Just a slavish obsession with big, primitive drivers. The mid dome defeats its own existence.

Somehow people lap up that rustic conservatism. Perhaps because it allows them to point at these incremental improvements to justify their expense despite vastly more advanced designs on the market.

I have to correct some comments I made about the scm50 measurements from what tuga posted. It looks like it’s +/-2dB from 60-20kHz, not 4-6dB at least according to stereoplay themselves.

And thanks for your subjective opinion Keith but I have to take your comments with a grain of salt because you’re a dealer. I was about to say you don’t represent atc so of course you wouldn’t feel obligated to praise a brand you don’t carry but you actually do carry atc since I visited your website to check.

You have the scm50 you mentioned listed on your site along with some words I noticed “'I have the simplest of tastes I am always satisfied with the best. ATC have and continue to make the very best loudspeakers available, the complete range of ATC loudspeakers and electronics are available from Purité Audio.”

Outdated text in your site from before you stated carrying Kii and Grimm speakers? We know you prefer DSP based systems. So I guess it would make sense you prefer those brands. Interesting how people can label a brand as “the best” but a few short years later the latest and greatest thing overtakes it completely...

Not sure what to think, I will have to do a lot more research and of course hear the speakers myself. One thing that I wonder about atc and why someone might not be enamoured with their sound is the fact that apparently atc needs placement in treated rooms to sound their best and also I’ve heard reports at least regarding the scm150 that they sound rather unengaging at low volumes. Could anyone offer a suggestion why that may be?

Notwithstanding whatever Keith sells, ATC speakers are backward. They are the very antithesis of a design like your JBLs - namely controlling dispersion and modern driver designs (eg. JBL differential drive woofers and the D2 compression driver). This is seen in the pedestrian directivity performance and clunky box.

 

[Rick Sykora]

CtC = centre to centre spacing.

Because of that old-fashioned motor design, it has a huge, bulky flange/driver frame that increases CtC spacing needed. For a given crossover frequency, larger CtC = worse vertical performance due to lobing. Now this driver is well-behaved to a pretty high frequency. But all that performance is wasted because you have to cross it lower than that (thus defeating the point of the expensive driver), or start compromising vertical performance and make it very finicky to listening height.

Hence the comparison to Neumann's mid dome, which has almost JBL M2 level of measured headroom and distortion in a much more compact frame and vastly better directivity control than that ATC paperweight. I frankly don't rank them much higher than PMC or Harbeth.

Have never heard the Neumann’s, but they are pretty pricey here in the states. For close to $10K a pair for the KH420, I have really high expectations. I know stuff in Singapore is generally even more, but if am just spending freely, the JBL M2 seems like a lot more speaker?

 

[andreasmaaan]

I guess that the dip at 3.5kHz is bad?

I guess you could say it is bad since it looks like it's caused by the breakup resonance of the mid dome.

I doubt the dome mid is breaking up that low in frequency. Much more likely to be destructive interference around the XO point IMHO, especially given we see evidence of lobing around the same frequency in the vertical off-axis measurements.

 

[tuga]

They are the very antithesis of a design like your JBLs - namely controlling dispersion and modern driver designs (eg. JBL differential drive woofers and the D2 compression driver). This is seen in the pedestrian directivity performance and clunky box.

Why do you assume that what he likes about his JBLs (or doesn't, since he is looking at replacing them) is the result of controlling dispersion and modern driver designs?

 

[tuga]

I doubt the dome mid is breaking up that low in frequency. Much more likely to be destructive interference around the XO point IMHO, especially given we see evidence of lobing around the same frequency in the vertical off-axis measurements.

Maybe you are right. Here are a couple of CSD plots:

 

[Ilkless]

Why do you assume that what he likes about his JBLs (or doesn't, since he is looking at replacing them) is the result of controlling dispersion and modern driver designs?

Both are in a similar form factor, and he has mentioned high dynamics is a priority, so I can't imagine anything else. The ATCs would be at best a sidegrade for max SPL/dynamics and a clear downgrade in linearity and dispersion control. Sure, there's that mid dome that has a cult of personality, but that's all it has. It doesn't have superior midrange performance to the top JBL stuff. The mid dome's very existence is self-defeating because it can't even be crossed optimally for its passband (plus the 3.5kHz anomaly is inexcusable considering how much that driver costs). Which speaks to the slavish obsession with primitive, huge drivers, rather than engineering the loudspeaker as a system with these British brands.

Have never heard the Neumann’s, but they are pretty pricey here in the states. For close to $10K a pair for the KH420, I have really high expectations. I know stuff in Singapore is generally even more, but if am just spending freely, the JBL M2 seems like a lot more speaker?

I have heard the Neumanns. I have no doubt they are state-of-the-art for that size. The M2s are much larger, though I'll concede anyone who can fit a speaker like the KH420 shouldn't have much trouble fitting an M2. Nonetheless, M2 are retailing around 20k for the powered, DSP setup (for a fair comparison). I understand that street prices are lower, but I'm not sure how much lower to make them price-competitive. The measurements (S&R magazine) show the Neumann has smoother polars and FR (because of the compression driver in the JBL), but lower max SPL (still SOTA for the Neumann size). JBL has great polars and FR, especially for a compression driver, but the big asset is even higher max SPL:

Then, there's the ATC dome for a fairer comparison:

Looking at just the passband for the ATC vs Neumann dome (500-3kHz), the ATC dome has 10dB less headroom. For a similarly-sized radiating surface. Neumann's dome has a much tighter CtC spacing, so directivity is better as well. I certainly can't see any ATC dome magic.

 

[Ilkless]

Have never heard the Neumann’s, but they are pretty pricey here in the states. For close to $10K a pair for the KH420, I have really high expectations. I know stuff in Singapore is generally even more, but if am just spending freely, the JBL M2 seems like a lot more speaker?

PS: yes, audio equipment is generally more expensive. But in an ironic coincidence, the local ATC distributor has the best ATC prices I've ever seen anywhere in the world (even in the UK). He just launched this deal offering SCM19s at a discounted price (2.1k USD) with free shipping to the door. SCM19 US price: 4k.

But Neumann/Genelec prices can't compare to street prices in Europe, especially ex-VAT.

 

[localhost127]

It's also worth mentioning here that Toole research in this area is clearly limited to the acoustic environments he experimented with. If you have for instance a late lateral diffuse tail in the room, things can change quite dramatically.

i agree. i inquired numerous times at AVS and he was kind enough to respond and is very forth-giving that it is simply a matter of taste. and that certain people (professionals, studio engineers) would perhaps prefer a more objective (accurate) response for reproduction (for both working and pleasurable listening) than others that would subjectively prefer their own tastes (vs use of polls are surveys) - all very valid conclusions.

and as you reference, there is seemingly almost always a complete lack of discussion on the later-arriving sound-field in such circumstances. many will "remove" lateral energy via attenuation of first-order sidewall reflections, but completely ignore the re-introduction of that later energy via the use of 1-dimensional phase grating diffusers to provide a very dense, lateral reflection-rich diffuse tail to provide a sense of spaciousness and envelopment (coming from the rear wall/rear side wall directions) - whose decay also emulates the linear slope found naturally in large acoustical space reverberant sound-fields. you get the best of both words: a large ISD where-by only the direct signal is allowed to be "heard" (increasing the acoustical perceived size vs what the room's natural boundaries allow), increasing accuracy of direct signal in terms of localization, imaging, and speech intelligibility - and then providing a sense of the room (and in fact a sense of a much "larger" room) via the sparse reflections being converted into dense, reflection-rich, diffuse reflections and their lateral direction for spaciousness and envelopment.

so the comparison and testing should never (in my opinion) simply be: "allow sidewall reflections vs absorbed sidewall reflections", it should be something akin to "allow sidewall reflections vs attenuated sidewall reflections with later-arriving dense, reflection-rich lateral diffuse sound-field". it's a completely different response and perception. you are removing some lateral energy, but re-introducing it to the listening position at a later-time (in a managed fashion).

 

[localhost127]

You jumped into this conversation:

i jumped in because you made a claim that the ETC is "extremely unreliable measurement". you then went on to provide a corner-case example of analysis of speech signals band-limited at 500hz. i do not know any acoustical engineer that measures and modifies a bounded acoustical space (to meet a given set of design requirements) by utilizing band-limited 500hz speech signals. i personally never have used this methodology in a home reproduction environment and i'm curious as to why the reference.

you can also have two very similar frequency-response plots, yet "sound very different" - what's your point? the operator must be smarter than the tool he/she is using and understand the data, limitations, and how it can be correctly (accurately) applied. i don't see anyone running around after each/every frequency-response post with all of these "caveats" of how the "frequency-response is extremely unreliable".

i in no way see where it has been qualified that the timing aspect (thus corresponding to flight path of indirect specular energy) is unreliable. the one case is with electronic delay, which can be accounted for with a simple loopback within the measurement system.

it's akin to standing in home depot loudly proclaiming to anyone buying a specialty tool how they are "not smart enough to use it" and "if you use it wrong you will get incorrect results". duh! we know! the operator must be smarter than the tool.

I explained what they issues are in interpreting them. And their usefulness. And the signal processing behind it. As asked by Ray.

You challenged my statement so I explained it again in more detail.

If you are asking simply if you can use ETC for timing detection, which is not what was asked or being discussed, you can. There are dead simple substitutes that don't require ETC such as just looking at the room, using a mirror, tape measure, etc.

i already have my measurement equipment out to analyze other perspectives of the speaker-room response (eg, frequency domain). the mirror is not a measurement device. for someone so focused on data and science, why would one use a visual aid vs actual measured data to understand how indirect energy impedes the listening position over time? this is contradictory.

a mirror was first put forth by d'antonio during certain syn aud con workshops to illustrate the specular nature of reflected wavelets (ie, angle of incidence = angle of reflection). it was not meant to be considered a "measurement device" like actual TDS/time-domain analysis. secondly, a mirror only illustrates obvious sources of indirect reflections - not non-obvious sources. if you actually spend time and experience modifying existing bounded acoustical spaces, you will certainly come across scenarios where "non-obvious" sources of colored, high-gain indirect reflections exist and by solely using the mirror would have never discovered them.

But if you want to use ETC, is fine. Just don't go to the next sentence as you do that people should assign value to those reflections and go and try to eliminate them all. If you do, then you run foul of what I explained.

to be frank: you seem to have this habit of associating the use of a tool (the ETC/time-domain analysis) as an automatic insinuation of implying that "every spike of energy must be attenuated". it's quite frankly laughable. a user first sets forth time-domain requirements - and the ETC is used to understand existing environment and thus what modifications need to be made in order to meet the end-state response. a tool does not "tell you what to do". a user identifies where they are currently at, and their end-state, and the tool helps provide validation after the changes have been made.

 

[QMuse]

to be frank: you seem to have this habit of associating the use of a tool (the ETC/time-domain analysis) as an automatic insinuation of implying that "every spike of energy must be attenuated". it's quite frankly laughable. a user first sets forth time-domain requirements - and the ETC is used to understand existing environment and thus what modifications need to be made in order to meet the end-state response. a tool does not "tell you what to do". a user identifies where they are currently at, and their end-state, and the tool helps provide validation after the changes have been made.

Ok, here's ETC of my left speaker taken from LP, let's here your analysis of it and eventual suggestions.

I would also appreciate if you post ETC of your speakers, for comparison and discussion.

 

[localhost127]

Membership here is not familiar with you, your personality and knowledge level. I wanted to make sure they were up to speed that you just repeat stuff you learned from some old text (Davis) which you misread and some random dude online who claimed to know the topic. And that you will grab on someone's pant leg and won't let go with this ETC talk. If none of this is you, then update us so we know.

then by all means, please qualify your personal attack that i somehow lead people to "screwing up their rooms", "spending a ton of money uglifying them to boot". just provide one example of someone claiming their room was "screwed-up" - or take back your personal attack.

you don't need to feel so threatened just because of others use science, logic, and data for acoustics and psycho-acoustics. you don't need to feel threatened everytime someone recommends time-domain analysis. we all remember that time on AVS when you finally realized what the x-axis of the ETC actually represented (even though you were argueing about the tool for weeks at that point).

spend some time learning how to actually measure and modify a room to meet a set of design requirements. it will make much more of my commentary relatable and understandable vs someone who has not done so.