ATC speakers / Monitors

[Pearljam5000]

Why do they stick to soft domes and not move to metal domes?

 

[dfuller]

Why do they stick to soft domes and not move to metal domes?

Well these days they're making them in house, and doped cloth is easy to deal with. They'd have to contract out diaphragm manufacture.

Their other reasoning before that was the fact that a lot of metal domes have fairly violent breakup modes relatively close to the audible spectrum.

 

[Chrise36]

If we ignore the soft dome beaming, they measure pretty good actually.

Justs confirms what listening experience of thousands of users and some of us here are talking about all these years.

 

[goat76]

The matched pair, with a deviation of only about 0.4 dB (and for the most part around 0.3 dB), is also quite impressive for a pair of passive speakers. The reviewer said it was the best he had ever measured. That makes for a very precise and stable stereo image.

 

[Sokel]

It appears our good friend @Nuyes has measured the SCM20SL Mk2.

It is considerably better than the SCM19 reviewed here.

ATC SCM20SL MK2 리뷰 Audio-re

2way closed, 55.3 Hz (-6dB)

audiore.kr

Zero experience with the small ones but what we see pretty much correlates with decades of talks about ATC minus the dome mid.
Lean, controlled bass, low distortion, good higher SPL handling, picky about placement, etc.

These ones seem bright too on-axis and as they are pretty small (so better for nearfield) , I wonder if someone can get around it placing them so the on-axis excessive highs get a self or DSP them at such way.

 

[574stereo]

It seems these were measured with the grilles removed which leaves hard-edged baffles. The grille has a rolled-edge built in behind the cloth (which is then supported from a very thin frame sitting in front of the whole speaker). Without this you're going to wind up with edge-diffraction issues

I wonder how the off-axis measurements would have differed if they'd been measured grilles on.

 

[Purité Audio]

Apparently ATC have approached a U.K. Klippel NFS owner.
Keith

 

[dfuller]

Apparently ATC have approached a U.K. Klippel NFS owner.
Keith

That's encouraging.

It seems these were measured with the grilles removed which leaves hard-edged baffles. The grille has a rolled-edge built in behind the cloth (which is then supported from a very thin frame sitting in front of the whole speaker). Without this you're going to wind up with edge-diffraction issues

I wonder how the off-axis measurements would have differed if they'd been measured grilles on.

The off axis flare and diffraction artifacts around 4-6k would have been lessened some.

 

[pablolie]

The matched pair, with a deviation of only about 0.4 dB (and for the most part around 0.3 dB), is also quite impressive for a pair of passive speakers. The reviewer said it was the best he had ever measured. That makes for a very precise and stable stereo image.

Uhm, what's the possible deviation from true accuracy? Measuring speakers often means in several cases you have a possible +/- 1dB accuracy envelope. 0.3dB is well below something that can be accurately and repeatably measured in several cases...?

 

[Gregg Hermetech]

It appears our good friend @Nuyes has measured the SCM20SL Mk2.

It is considerably better than the SCM19 reviewed here.

ATC SCM20SL MK2 리뷰 Audio-re

2way closed, 55.3 Hz (-6dB)

audiore.kr

Thanks for finding and sharing this. I'd LOVE to know how the active Pro versions (what I use and am very happy with) measure in comparison.

 

[dfuller]

Thanks for finding and sharing this. I'd LOVE to know how the active Pro versions (what I use and am very happy with) measure in comparison.

Probably similar, albeit with less edge diffraction nonsense around 4-6k.

 

[Gregg Hermetech]

Probably similar, albeit with less edge diffraction nonsense around 4-6k.

I think the tweeters may be slightly different too, seem to remember reading somewhere (maybe the ATC site) the pro versions have greater power handling or something. Ah, here we go:

Technology - ATC Loudspeakers

atc.audio

"The standard SH25-76 and its ultimate 'S' spec stablemate approach these engineering challenges in different but equally successful ways. The standard tweeter has a novel and lighter moving mass bracing component, while the 'S' spec driver has an exceptionally powerful motor assembly that, when combined with the optimally stiff and lightweight coil former, delivers vanishing low levels of odd harmonic distortion and a well controlled extended frequency response beyond the limit of human hearing."

 

[Ktacos]

Tweeter dispersion on that bookshelf is mighty poor.

 

[Chrise36]

Zero experience with the small ones but what we see pretty much correlates with decades of talks about ATC minus the dome mid.
Lean, controlled bass, low distortion, good higher SPL handling, picky about placement, etc.

These ones seem bright too on-axis and as they are pretty small (so better for nearfield) , I wonder if someone can get around it placing them so the on-axis excessive highs get a self or DSP them at such way.

Near wall placement grilles usage and compression must be taken into account.

 

[Pearljam5000]

When is ATC going to make a coaxial to compete with Genelec?

 

[Sokel]

Near wall placement grilles usage and compression must be taken into account.

Grilles showed strange results at the measurements, I'm not sure they are usable.

 

[dfuller]

Grilles showed strange results at the measurements, I'm not sure they are usable.

Ultimately the pro versions are the better versions here; they have proper roundovers without grilles.

Tweeter dispersion on that bookshelf is mighty poor.

It's surprisingly even until it beams, and boy does that happen violently.

 

[goat76]

Uhm, what's the possible deviation from true accuracy? Measuring speakers often means in several cases you have a possible +/- 1dB accuracy envelope. 0.3dB is well below something that can be accurately and repeatably measured in several cases...?

For a simple, straightforward measurement, which is all that is needed for this particular measurement when comparing sample to sample deviations on the on-axis response, I’m pretty sure the Klippel NFS is capable of an accuracy of +/- 0.1dB, as there is no need for anything to be calculated.
The most critical thing here is how accurately they managed to position the second speaker, in accordance with the first speaker's position on the Klippel device. I mean, even a back-to-back on-axis measurement with REW in a home environment can be done with way better accuracy than +/- 1dB, as long as everything stays in the same physical position between the measurements.


Amir gave you this answer in another thread:

“No, these are the specs:
Measurement accuracy:
In maximum SPL direction 1+/- 0.1 dB
In all directions +/- 1 dB

Maximum SPL occurs in on-axis response so accuracy can be incredibly good. There is a drop off in off-axis because the microphone is being used in other angles. There is no compensation for this but I don't use it.

Ultimately the accuracy is limited by the calibration of measurement microphone and number of measurement points uses to compute the response.”

 

[goat76]

I think the tweeters may be slightly different too, seem to remember reading somewhere (maybe the ATC site) the pro versions have greater power handling or something.

"The standard SH25-76 and its ultimate 'S' spec stablemate approach these engineering challenges in different but equally successful ways. The standard tweeter has a novel and lighter moving mass bracing component, while the 'S' spec driver has an exceptionally powerful motor assembly that, when combined with the optimally stiff and lightweight coil former, delivers vanishing low levels of odd harmonic distortion and a well controlled extended frequency response beyond the limit of human hearing."

According to ATC's webpage, the SCM20SL MK2 does have the 'S' specified tweeter.

I'm not sure why the review page uses a picture of the old version of this speaker model, but if my memory serves me correctly, I think it took a while for ATC to update the images on their webpage when they upgraded all their speakers with the in-house built tweeter. This review appears to be dated 2023, and they clearly state that the source of the picture is the ATC's webpage.

 

[574stereo]

I had always thought they used an NFS but apparently not. A friend of mine (who has SCM20 actives) asked one of their R&D guys recently and the answer was either outdoor measurements or an anechoic chamber.