ATC speakers / Monitors

[Atc4ever]

...
The only reasons for the above that I can think of may be the differences between the S-spec tweeter and the Super Linear bass driver.

Long ago, Billy Woodman said that the goal of the atc company is not to invent something new, but to improve what already exists to the maximum.
Atc has spent many years perfecting its drivers.
S - tweeter and SL bass are the current crown of that work.
Why would it be hard to believe that those components are audibly better than the lower spec ones?
IMHO that's exactly what you're hearing.

 

[AdrianusG]

ATC prioritizes the lowest possible level of distortion in all their loudspeaker designs, and lets the physics dictate the bass extension. Even with their bass-ported speakers, they never utilize the port for deeper bass extension, and rather use it to lower the level of distortion resonances even further. If you need deeper bass extension, you either buy larger ATC loudspeakers or add subwoofers to your system.

People tend to hear cleaner bass as less bass, as a higher level of distortion in the bass region tends to be perceived louder. That may be another reason why people think that ATC speakers are leaner in the bass.

I use subwoofers with all my ATC speakers, as I want a truly full-range sound. No small to medium-sized speakers can do that without a significant raise of distortion in the bass. I find people often contradict themselves when buying small loudspeakers with way too impressive bass extension, which they, on one hand, defend their decision by saying that the "human hearing isn’t that sensitive to distortion in the lower frequencies anyway", but right at the moment they add subwoofers, they immediately say that using a low-pass filter is a must to achieve a cleaner sound.

Yes that,

And most (consumer) models from ATC have no ports and therefore have a different bass response vs ported.
Anyways, I have the SCM 40's (passives) and without extra subs, I don't find them lacking in Bass, when it's in the source it is there,
not ground shaking of course, but for my middle sized room (well furbished) it's enough

Furbished = Furnished

 

[goat76]

Yes that,

And most (consumer) models from ATC have no ports and therefore have a different bass response vs ported.
Anyways, I have the SCM 40's (passives) and without extra subs, I don't find them lacking in Bass, when it's in the source it is there,
not ground shaking of course, but for my middle sized room (well furbished) it's enough

The first thing I thought when setting up my SCM40s was that they had less bass than my previous speakers, but pretty fast, I realized that they actually reach quite low. They just sounded cleaner with a more articulated bass sound, less of that type of "one-note bass" as some other loudspeakers with "artificially" added bass extension. But with that said, I still prefer a truly full-range sound, and with two seamlessly integrated subfoofers set up in a stereo configuration on each side of the main speakers, the SCM40s sound like way larger speakers than they are.

 

[Pearljam5000]

The first thing I thought when setting up my SCM40s was that they had less bass than my previous speakers, but pretty fast, I realized that they actually reach quite low. They just sounded cleaner with a more articulated bass sound, less of that type of "one-note bass" as some other loudspeakers with "artificially" added bass extension. But with that said, I still prefer a truly full-range sound, and with two seamlessly integrated subfoofers set up in a stereo configuration on each side of the main speakers, the SCM40s sound like way larger speakers than they are.

So you have ATC subs?

 

[AdrianusG]

So you have ATC subs?

Hi,

No, i don't have any subs, just the SCM40's but like i said in my situation/room it's enough for me

 

[AdrianusG]

Hi,

No, i don't have any subs, just the SCM40's but like i said in my situation/room it's enough for me

For instance,

When i play (Daftpunk's) Random Access Memories, or (Cory Wong's) Starship Syncopation, there's plenty bass to be heard in my room

 

[thewas]

The only reasons for the above that I can think of may be the differences between the S-spec tweeter and the Super Linear bass driver. I really don't know if the technical differences translate to real-world sound differences, so please, take the information below with a pinch of salt, as it comes directly from ATC's own literature.

Yes, I know that "marketing tech", I am afraid in the end only the comparative measurements I had mentioned might show possible reasons to explain what you hear.

 

[Blockader]

I've read a lot of times that ATCs lack bass and have less output than speakers of the same size
Why is that?

I really want to believe that it is for a good cause: Linear BL over a long stroke costs sensitivity, buys low distortion.

However, the 3rd party results tell us a different scenario.

A response that falls off a cliff around 50-55 Hz from a 150 L cabinet with 15" drivers, paired with over 4% distortion at 82 dB, doesn't speak to strong engineering for 2026.

https://audiostereo.ro/ATC reviews/atc_el150psl_rev-stereo_russia.pdf

Full link above.

 

[goat76]

So you have ATC subs?

No, I have two REL S/510 in my system.

 

[DatSpeakerTho]

ATC prioritizes the lowest possible level of distortion in all their loudspeaker designs, and lets the physics dictate the bass extension. Even with their bass-ported speakers, they never utilize the port for deeper bass extension

ATC simply does ports wrong, plain and simple. I have a 100l ATC clone box, I know how the ports work in this volume and I know how ATC does their ports and cabinet damping. ATC restricts their port air with damping material reducing it's efficiency. This is also why distortion down low is high where it should be much lower. I assume they have to do this as these tall boxes have pretty nasty height related resonances. Putting the port on the front insures any leaking reosnances will be in a tube facing the listener. Placing the port in the corner of the cabinet insures that the cabinet resonances will be at their highest pressure. Their ports also effectively have no end correction, which is kind of embarassing for 2026 (it was behind the times in 2010). I swear everything ATC does is just always well behind the times.

Personally, I built ports the right way. I don't restrict air flow to them. I place them in a locations that minimize cabinet resonance leakage, I have end correction and my ports are constant curvature.

I look forward to hearing from ATC owners as to how doing ports wrong is actually a good thing lol. Good port examples are from Neumann, Genelec, and others.

 

[goyt]

I really want to believe that it is for a good cause: Linear BL over a long stroke costs sensitivity, buys low distortion.

However, the 3rd party results tell us a different scenario.

View attachment 540288
A response that falls off a cliff around 50-55 Hz from a 150 L cabinet with 15" drivers, paired with over 4% distortion at 82 dB, doesn't speak to strong engineering for 2026.

https://audiostereo.ro/ATC reviews/atc_el150psl_rev-stereo_russia.pdf

Full link above.

Is distortion often measurably lower at higher volumes?

 

[Blockader]

Is distortion often measurably lower at higher volumes? Higher distortion than the SCM7 on the previous page seems somewhat unlikely.

Are you sure? The distortion here is around 20% distortion despite the acoustic assistance of room gain. The legend values are readings at the cursor position on the frequency axis, not necessarily at 50 Hz where the spike appears. Nevertheless 20% distortion around 90 dB is usually the ballpark distortion behavior for a speaker like SCM7.

 

[574stereo]

I really want to believe that it is for a good cause: Linear BL over a long stroke costs sensitivity, buys low distortion.

However, the 3rd party results tell us a different scenario.

View attachment 540288
A response that falls off a cliff around 50-55 Hz from a 150 L cabinet with 15" drivers, paired with over 4% distortion at 82 dB, doesn't speak to strong engineering for 2026.

https://audiostereo.ro/ATC reviews/atc_el150psl_rev-stereo_russia.pdf

Full link above.

There is absolutely no way that's a correct measurement for the 150. It's a 15" woofer in a large enclosure, tuned very low... Something's wrong with those freq. response measurements (which would also explain why the THD% skyrockets so suddenly)...

 

[dfuller]

There is absolutely no way that's a correct measurement for the 150. It's a 15" woofer in a large enclosure, tuned very low... Something's wrong with those freq. response measurements (which would also explain why the THD% skyrockets so suddenly)...

I agree with this. This looks considerably worse in both bass extension and distortion than the SCM25A, which makes zero sense.

 

[Atc4ever]

According to ATC, the passive version of the SCM20 “has been in continuous production since 1990 and has evolved through four driver/crossover revisions into its current form”.

I can't answer your question about what might have changed in the sound over the years, as the pair of the SCM20s (latest revision) I have now is the only pair of 20s I have heard. But what I can say is that I‘m impressed with the sound of this loudspeaker; it sounds crystal clear, clean, precise, and is brutally revealing of the music source.

While both the SCM11s and the SCM40s also have a revealing, clean, and highly detailed sound, the SCM20 is a step up in the “clear department”. I don't know if that has to do with the “S-spec” tweeter and the “Super Linear” mid/bass driver found in the SCM20s, as the other two models already show a very low level of distortion in their measurements.

Maybe something will show up in the measurements I will do at some point, but at this moment, I just want to listen, adjust the speaker placement to perfection, and fine-tune the subwoofer's level and crossover point for a totally seamless integration with the main speakers.

I'm curious about something.
Given that you have already discovered what kind of sound quality the scm20 can provide, what specific benefit you expect from the measurement results and how they can change or confirm your opinion about these speakers that you have already formed based on listening.

 

[goat76]

Is distortion often measurably lower at higher volumes?

Just ignore users who obviously search the internet for the worst measurements they can find, and ignore all other available measurements that show that their picked one is at odds with pretty much everything else they can find.

Such behavior is actually highly disrespectful to a forum like ASR and to other members here who strive for accurate information.

 

[DSJR]

In my small room and long before Umiks or REW, my 100As were pretty neutral to 45 - 50Hz, th eoutput gently falling away to 25Hz or so, which was still cleanly reproduced subjectively! Next to nothing came out of these pre-SL era ports and the active amps helped as they filtered everything off below 20Hz I gather. The ports for the 100SL drivers were much longer and wider I remember, but no experience of how the bass changed subjectively.

The SL drivers do seem to offer greater lower-midrange clarity over the originals pre 1996 or so and on the larger units, the 'heatsinks' fitted around the bass driver magnets (what they looked like but no idea if it was just a chunky bit of trim really), were removed. My take on the 20ASL was that the increased clarity in the upper midrange, clashed with the response lift the 20 already had and emphasised the forward nature and relative lack of bass. The 20ASL Pro has a bass-lift control, but to me it goes 'one-note-thumpy' and still lacks 'depth' of tone that 'looser' speaker models can offer.

 

[7Tiger]

ATC simply does ports wrong, plain and simple.

Yes, they do. But not in all of their ported models.

tall boxes have pretty nasty height related resonances. Putting the port on the front insures any leaking reosnances will be in a tube facing the listener

This applies mainly to relatively compact 2-way designs, larger speakers aren't affected by this that much

Their ports also effectively have no end correction

You mean they aren't flared on both ends ?

Personally, I built ports the right way. I don't restrict air flow to them. I place them in a locations that minimize cabinet resonance leakage, I have end correction and my ports are constant curvature

Mind sharing some pics ? Genuinely curious being a speaker builder myself.

 

[goat76]

I'm curious about something.
Given that you have already discovered what kind of sound quality the scm20 can provide, what specific benefit you expect from the measurement results and how they can change or confirm your opinion about these speakers that you have already formed based on listening.

I’m recording, mixing, and mastering my own music in my spare time; therefore I want to be sure that the loudspeakers are neutral enough so that they can be trusted.

I also need to see how the low end measures now that I have raised the crossover point to suit the SCM20s instead of the SCM40s. There is likely some EQ adjustments needed in the lower frequency range, and maybe a bass shelf or a tilt to the overall balance, as the SCM20s sound slightly brighter than the SCM40s.
There is likely not much needed, as I already find this speaker to sound quite good as it is.

 

[RexrothPigeon]

Just ignore users who obviously search the internet for the worst measurements they can find, and ignore all other available measurements that show that their picked one is at odds with pretty much everything else they can find.

Such behavior is actually highly disrespectful to a forum like ASR and to other members here who strive for accurate information.

A real cool and easy way to preclude this is if ATC would just release their measurements