ATC speakers / Monitors

[q3cpma]

I have no problem with your persistence. While looking at the Stereoplay pictures above, on the right side (active ATC), I can see 60 degrees loss is less than 10db at 10khz and 15db at 20khz. To me that looks rather good.

This only characterizes the width of the dispersion, which is mostly a taste and musical material thing. Smoothness, on the other hand, is crucial as the on-axis sound will be affected by the off-axis to some degree thus a compromised resulting tonality, and the bunching around 4~5 kHz along with the strange 10° rollercoaster is definitely subpar.

 

[andreasmaaan]

Does anyone here think that crossing over to the ATC mid at 380Hz (like it is done in the ATC line) is a bit too low and creates distortion / compression at high SPL levels?

I haven't found any measurements of the midrange dome or speakers using it at high SPLs, but based on its performance at moderate SPLs, the crossover frequency of 380Hz seems to be perfectly fine.

The issues with these speakers are not related to distortion, power handling or driver performance (other than, arguably, some in-band breakup on the soft-dome tweeter).

Rather, where all ATCs I've seen measurements of fall short is in linearity and (as @q3cpma mentioned) in dispersion.

At th end of the day, ATC drivers range from good to excellent; it's in loudspeaker (whole system) design that they lose out to other manufacturers due to uneven axial frequency response and chaotic off-axis dispersion.

 

[ctrl]

Does anyone here think that crossing over to the ATC mid at 380Hz (like it is done in the ATC line) is a bit too low and creates distortion / compression at high SPL levels?

The harmonic distortions (or IMD) is certainly not a problem.

I have no problem with your persistence. While looking at the Stereoplay pictures above, on the right side (active ATC), I can see 60 degrees loss is less than 10db at 10khz and 15db at 20khz. To me that looks rather good.

The horizontally asymmetrical arrangement of the midrange and tweeter is a problem if you value the most even radiation possible.

The reflections that reach your ear should have a frequency response as similar as possible to that on axis. This prevents the brain from classifying the incoming signals as different sound sources and prevents the sound character of the LS from changing at high sound pressure (when the diffuse sound has a greater influence).

Of course, the absorption behavior of the listening room plays a major role here - the speaker manufacturer cannot influence this. But he can ensure that the loudspeaker is as uniform as possible in its sound radiation.

The asymmetrical arrangement of the drivers on a baffle with "hard edges" has an advantageous effect on the frequency response on axis (if optimally arranged), because the interference of the edge diffraction will then be balanced out to a certain degree.
Due to the asymmetrical arrangement, the propagation time to the side edges is different and thus the horizontal angle measurements for the right and left side will be different.

As an example, let's look at a listening room with the first order reflections (reflections with one reflection point) of a loudspeaker to the listener. The loudspeaker is parallel to the side wall:

Now it would be desirable that the frequency responses of the reflections correspond as much as possible to those of the direct sound (in our example the 20° FR).

For this we look at the horizontal frequency response measurements of the loudspeaker. Here are the simulated frequency responses 0°, 10°, 20°...180° of a loudspeaker with a large, symmetrically arranged waveguide.

In the diagram, the 20° FR has been normalized to better compare how much the reflections at 40° and 60° differ from it.

The 40° FR hardly differs from the 20° FR. The 60° FR drops evenly to high frequencies, compared to the 20° FR.
There are no sudden rises or crossing FRs.

The whole thing again in the spectrogram representation, there the individual FR are less well to be recognized, but for it one can recognize that the loudspeaker has very evenly directivity.

To be able to assess this, you need comprehensive measurements of the LS, which are unfortunately not available for the ATC SC150.
Therefore, it is difficult to estimate how much the asymmetrical arrangement of the drivers affects the directivity of the LS - of course, only if the directivity of an LS is important for you


Using the limited measurements (in a horizontal direction) of the ATC SM50 from post#179, the following graph results if normalized to the axis frequency response:

That's not bad so far, but it could be better

UPDATE: In reality, everything is much more complicated and the explanations I have given are very simplified.....

 

[Chrise36]

If this is not ultra low I am not sure what this is. Link: https://www.hifinews.com/content/atc-scm100se-loudspeaker-lab-report

There is also a russian review if anyone can translate that shows thd is lower in 94db than 88db etc.

I haven't found any measurements of the midrange dome or speakers using it at high SPLs, but based on its performance at moderate SPLs, the crossover frequency of 380Hz seems to be perfectly fine.

The issues with these speakers are not related to distortion, power handling or driver performance (other than, arguably, some in-band breakup on the soft-dome tweeter).

Rather, where all ATCs I've seen measurements of fall short is in linearity and (as @q3cpma mentioned) in dispersion.

At th end of the day, ATC drivers range from good to excellent; it's in loudspeaker (whole system) design that they lose out to other manufacturers due to uneven axial frequency response and chaotic off-axis dispersion.

Video measurements at 100db if i saw correctly

 

[Deleted member 4708]

@ctrl - thanks for your explanation. Much appreciated.
When you are facing the speakers, toe-in 60 degrees isosceles triangle, it seems to me the directivity of the speaker matters less. Is that correct, or am I oversimplifying too much?
Most of my listening is from a big couch with toe-in speakers at 60 degrees in front of me - I think the couch absorbs a lot of the sound and there are very little reflections from the wall behind me.

 

[andreasmaaan]

Video measurements at 100db if i saw correctly

This is similar to the previous discussion about the Jeff Bagby measurements.

100dB @ ~ 20-30cm
= ~ 88dB @1m

 

[Chrise36]

This is similar to the previous discussion about the Jeff Bagby measurements.

100dB @ ~ 20-30cm
= ~ 88dB @1m

It still looks ultra clean.There are older measurements in 95ish db at 1m from diyers but difficult to find the pictures on old forum threads

 

[andreasmaaan]

It still looks ultra clean.There are older measurements in 95ish db at 1m from diyers but difficult to find the pictures on old forum threads

Yep, it's a very low distortion driver.

 

[andreasmaaan]

@ctrl - thanks for your explanation. Much appreciated.
When you are facing the speakers, toe-in 60 degrees isosceles triangle, it seems to me the directivity of the speaker matters less. Is that correct, or am I oversimplifying too much?
Most of my listening is from a big couch with toe-in speakers at 60 degrees in front of me - I think the couch absorbs a lot of the sound and there are very little reflections from the wall behind me.

Chaotic horizontal dispersion will be less of a problem if early lateral reflections (ie sidewall reflections) are absorbed. The couch and the front wall (wall behind the speakers) don't play much of a roll in this respect.

Many listeners, however, prefer strong lateral reflections, as they enhance perceived spaciousness. For such listeners/rooms, a speaker with smooth horizontal dispersion will be very important.

This is less the case in a typical control room or mixing studio context, where early reflections tend to be aggressively absorbed. Arguably in such cases, well-controlled dispersion tends to be less important (although not totally unimportant).

As per @ctrl's disclaimer, I'm speaking in very general terms here. Things are not quite so clear-cut in reality, and other factors also come into play. Nevertheless, regardless of listener preference and listening conditions, smoothness/flatness in the on-axis frequency response and smoothly controlled dispersion tend to be among the subjectively most important factors in loudspeaker performance.

 

[Deleted member 4708]

@andreasmaaan - got it! thx!

 

[dfuller]

This is less the case in a typical control room or mixing studio context, where early reflections tend to be aggressively absorbed. Arguably in such cases, well-controlled dispersion tends to be less important (although not totally unimportant).

This is actually a really important point that I think some don't take into account. Home audio is a totally different ballgame acoustically. Like, I must have over a hundred pounds of broadband and low end absorbers on the walls in my small (~160ft^2) mix room, and it could use more.

 

[richard12511]

This is actually a really important point that I think some don't take into account. Home audio is a totally different ballgame acoustically. Like, I must have over a hundred pounds of broadband and low end absorbers on the walls in my small (~160ft^2) mix room, and it could use more.

Not always . Hard to say for sure, but I'd guess I've have 300lbs at least in my listening room. Room is quite a bit larger, though. In general, I agree, though.

 

[dfuller]

Not always . Hard to say for sure, but I'd guess I've have 300lbs at least in my listening room. Room is quite a bit larger, though. In general, I agree, though.

It's certainly not universally the case, but it's a common one that dispersion control is somewhat less forefront in design for a number of studio monitors because of the massive amounts of early reflection absorption. Rather the focus is (ostensibly) on low distortion and flat on-axis response.

 

[outfaced]

Just saw this on Facebook, asked the guy what is that fabric , he said :
" felt to eliminate diffractions".
Does it make any sense?
View attachment 94041

I have tried much with different type of such kind "damping" but found it better without. Its good only if you listen form a sweet spot and the room is not treated. Otherwise it gets smoother but not in the good way ... or at least i missed the sharpness.
The only thing what i found to be general better is rounded corners of the baffle around the HF. Anything on the side of the mids drastically worsen the sound. A small reflection wall under the mids although makes them more audible when you are standing and not sitting on the HF axis without worsen the image.

and when we talk about a mid-drivers ... i think meanwhile there are already few pretty good out there.
luckily the other brands also develop

SEAS-W12CY006
http://www.troelsgravesen.dk/SEAS-W12CY006.htm
http://www.troelsgravesen.dk/CNO-GRANDE.htm

 

[Dialectic]

At th end of the day, ATC drivers range from good to excellent; it's in loudspeaker (whole system) design that they lose out to other manufacturers due to uneven axial frequency response and chaotic off-axis dispersion.

This fixation on the ATC soft-dome midrange driver (which appears to be very good) is an instance of the classic and ubiquitous audiophile mistake of focusing on one element, component or performance characteristic at the expense of holistic performance. I formerly made this mistake over and over, obsessing over amplifiers with high slew rates, DAC chipsets, and materials used in tweeters.

 

[outfaced]

indeed

but another word on this topic - best mids in the world

 

[Deleted member 4708]

Some interesting details on ATC drivers: http://www.audiostereo.ro/ATC_technology.html

 

[Pharos]

This thread is a long one with much to-ing and fro-ing.

My view of ATC, having had four pairs of their larger speakers, and rebuilt and modified the last, a pair of SCM100As, is that the company is a very good example of solidity in its quality of engineering, and resultant reliability. The speakers are work-horse tools which are very good and probably not aimed at the audiophile public, but more at studios where they are a working tool.

(I remember well a conversation with a Sales Director in which he stated that Hi-Fi people generally were mad ;-), .)

In a domestic environment they are perhaps not as appealing, because at home we want to immerse ourselves in a sumptuous sound field which to us replicates an event before us as though we are at a performance.
In a studio a mixer wants to forensically know what is on the recording, but this can at home, interfere with the enjoyment of the art.

I compare this with that of having purchased a new oak dining room table, and admiring its beauty, but on using a magnifying glass, then seeing some of the chiselling marks, and other slight imperfections.

Post 128 mentioned the possible long term problem with class D amplifiers, and yesterday I read an article which claimed that they are more reliable and had a greater longevity than class AB.

 

[YSC]

This thread is a long one with much to-ing and fro-ing.

My view of ATC, having had four pairs of their larger speakers, and rebuilt and modified the last, a pair of SCM100As, is that the company is a very good example of solidity in its quality of engineering, and resultant reliability. The speakers are work-horse tools which are very good and probably not aimed at the audiophile public, but more at studios where they are a working tool.

(I remember well a conversation with a Sales Director in which he stated that Hi-Fi people generally were mad ;-), .)

In a domestic environment they are perhaps not as appealing, because at home we want to immerse ourselves in a sumptuous sound field which to us replicates an event before us as though we are at a performance.
In a studio a mixer wants to forensically know what is on the recording, but this can at home, interfere with the enjoyment of the art.

I compare this with that of having purchased a new oak dining room table, and admiring its beauty, but on using a magnifying glass, then seeing some of the chiselling marks, and other slight imperfections.

Post 128 mentioned the possible long term problem with class D amplifiers, and yesterday I read an article which claimed that they are more reliable and had a greater longevity than class AB.

I respect your preference but I don’t think either argument is true, like the flatness of the top studio monitors are same as totl hifi speakers like the vivid G1 or KEF blade. You don’t get the special toning from those hifi ones but maybe more appearances care rather than cold dead studio design.

for longevity issue in post 128 is purely based on the fact that class D didn’t came out that long, but from pure electronics class D only activates in half the cycle compared to class A always on and generates much less heat, which is always no.1 enemy of electronics.

DSP might not get upgraded firmware after some years but I don’t think it will be something not repairable especially when speaker dsp don’t need a lot of processing power and act on the same audible frequencies so I expect it’s much more easy to apply a newer chip to do the same job with same profile loaded when repair is needed, much like capacitors still use the same holes/socket since it existed. This is different from expensive cameras or phones which have extremely limited space and layout and where a ton of processing power needed so when tech advances the better chip have completely different pin layout and impossible to apply

 

[Pharos]

I am not aware of stating or developing any argument in my last post, or of mentioning any speakers other than those of ATC, but I have stated my opinions which are based on my experiences of the differing needs of the Hi-Fi user, and those of a monitor in studio use.

I have also referred to another source in which class D amps were compared with AB in terms of reliability and longevity.
Please show me the errors in what you suppose to be my arguments.