In this review, we will be comparing SCM150PSL and SCM40, two Passive Floor-standing speakers by ATC.
Let's have a brief look at the main features
of ATC SCM150PSL and ATC SCM40 first before getting into our more
detailed comparison.
| Key Specs | ATC SCM150PSL | ATC SCM40 |
|---|
| Brand | ATC
United Kingdom · founded 1974 | ATC
United Kingdom · founded 1974 |
|---|
| Design | 3-way | 3-way |
|---|
| Tweeter | 0.98" | 0.98" |
|---|
| Midrange | 2.95" | 2.95" |
|---|
| Woofer | 14.76" | 6.46" |
|---|
| Frequency response | 60-17k Hz | 48-22k Hz |
|---|
| Sensitivity | 91 dB | 85 dB |
|---|
| Impedance | 8 ohms | 8 ohms |
|---|
| Power range | 100 to 1500 Watts watts | 75 to 300 Watts watts |
|---|
| Weight | 67.20kg / 147.8lbs | 31.00kg / 68.2lbs |
|---|
| Dimensions (H x W x D) | 34-13/16" x 19-5/8" x 22-3/8"
884.0 x 498.0 x 568.0mm | 38.58" x 14.57" x 12.01"
980.0 x 370.0 x 305.0mm |
|---|
What size room are the ATC SCM150PSL and ATC SCM40 speakers good for?
The size of the room in which you are planning to use these loudspeakers is an important decision
factor. Here we have compared their suitability to various sizes of environments considering their size
and max power parameters:
| Listening Environment* |
ATC SCM150PSL |
ATC SCM40 |
| Near-field |
Poor |
Poor |
| Small Room |
Average |
Average |
| Mid-size Room |
Good |
Good |
| Large Room |
Average |
Average |
| Very Large Room |
Poor |
Poor |
(* Approximate Room sizes: Small < 100sq. ft / 9 m2,
Mid-size: 100-220 sq. ft / 9-20 m2, Large 220-400 sq. ft / 20-36 m2, Very Large: >
400 sq. ft / 36 m2.
Average Floor Height: 9" / 2.7m. Typical room sizes differ from country to country, and the actual
listening experience changes depending on floor height, room shape, surface materials, listening
position, speaker locations, etc.)
The sections below take each area in turn: drivers, frequency response, physical size and what you get in the box.
Drivers
Both SCM150PSL and SCM40 are 3-way speakers.
ATC SCM150PSLATC SCM40
TweeterMidrangeWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
ATC SCM150PSL |
ATC SCM40 |
|
Driver Setup
|
3-way
|
3-way
|
|
Tweeter
|
0.98-inch
|
0.98-inch
|
|
Midrange
|
1 x 2.95-inch |
1 x 2.95-inch |
|
Woofer
|
1 x 14.76-inch
|
1 x 6.46-inch
|
SCM150PSL features a 0.98" Tweeter, a 2.95" Midrange and 1 x 14.76" Woofer with a Crossover frequency at 380Hz & 3.5kHz. On the other hand, the SCM40 features a 0.98" Tweeter, a 2.95" Midrange and 1 x 6.46" Woofer with a Crossover frequency at 380Hz & 3.5kHz.
Frequency Response
SCM150PSL has a frequency range of 60-17k Hz whereas SCM40 has a frequency range of 48-22k Hz. With a minimum frequency of 48Hz, the SCM40 can go significantly deeper on the low side and provide stronger bass compared to the SCM150PSL's min frequency of 60Hz.
The graph below depicts how these two speakers compare with the max, min and average Low Frequency values of other speakers in the Floor-standing class in our database.
Low Frequency
Floor-standing Speakers
Neither pair reaches down to 20Hz, the usual definition of full-range, which is normal for speakers of this size. If you want the bottom octave for movies or bass-heavy music, add a subwoofer to whichever you choose. Visit our Powered Subwoofers section to find out more about the available options.
Impedance and Sensitivity
SCM150PSL and SCM40 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. SCM150PSL sensitivity is rated at 91 dB and the SCM40's is at 85 dB. This 6 dB difference makes the ATC SCM150PSL a more sensitive speaker compared to ATC SCM40, hence will play louder with the same amount of watts.
Sensitivity
Floor-standing Speakers
Power Range
Power
range is the range of input power in watts RMS that a loudspeaker is designed to handle. Staying
within that range gives nominal performance; driving the speaker beyond its maximum wattage can damage it.
SCM150PSL can handle a max power of 1500 watts RMS, whereas SCM40 has a max power handling value of 300 watts RMS, 1200 watts less than the SCM150PSL.
Note that higher power handling does not make a speaker louder: that depends mainly on
sensitivity and impedance. The calculator below shows how loud each of these actually plays
on a real amplifier.
Which plays louder on your amplifier?
Starting with a popular amplifier - change it to the one you own, or any you are
considering, and watch both numbers move.
Input Type and Bi-Amping / Bi-Wiring
SCM150PSL features Binding Posts/4mm Plugs, tri-wire type posts and SCM40 has a Binding Posts/4mm Plugs, tri-wire type posts. None of these speakers feature bi-amping/bi-wiring.
Physical Specs
The size of a speaker can sometimes be an important decision factor due to space constraints or in some cases purely for esthetic reasons. In this section, we are going to compare ATC SCM150PSL's and ATC SCM40's external dimensions. ATC SCM150PSL has external dimensions of 884.0 x 498.0 x 568.0mm () whereas ATC SCM40 has external dimensions of 980.0 x 370.0 x 305.0mm (38.58 x 14.57 x 12.01inch).
ATC SCM40 is 128mm narrower and 263mm less deeper than ATC SCM150PSL but it is also 96mm taller.
Size, drawn to scale
Both speakers and both views share one scale, so everything here is directly comparable. Hover a box for its dimensions.
One scale for both, standing on the same surface and pushed back to the same wall, so the deeper one visibly sticks out further.
ATC SCM150PSL needs about 151% more floor or shelf area. ATC SCM150PSL is 263mm deeper, so it stands that much further out from the wall. ATC SCM40 is 96mm taller.
Base Surface Area Comparison
Base surface area of a loudspeaker may become a determining factor when the space in your room or desk is limited.
The base surface area of the ATC SCM150PSL is approximately 2828.6cm2 / 438.4inch2 and base area of the ATC SCM40 is approximately 1128.5cm2 / 174.9inch2. The SCM150PSL requires 151% more surface area than the SCM40 which gives it a small disadvantage on placement in tight spaces.
Weight Comparison The weight of a loudspeaker can become an important factor if you need to move and reposition the unit often. Weight of a speaker can also "sometimes" be an indicator of the rigidity of the enclosure and the quality of the internal components used. The ATC SCM150PSL weighs 67.20kg / 147.8lbs and the ATC SCM40 weighs 31.00kg / 68.2lbs. This makes the SCM150PSL 117% heavier than the SCM40.
Here is a comparison of how SCM150PSL and SCM40's weights compare with the average, max and min weights in Passive Floor-standing class.
Weight
All Floor-standing Speakers
 Max Input Power |
1500 watts
vs
300 watts
|
Handle more power from your amplifier |
 Sensitivity |
91 dB
vs
85 dB
|
Play louder with same amount of amplification power |
 Woofer Size |
14.76 inches
vs
6.46 inches
|
Larger woofer |
 Height |
884mm
vs
980mm
|
Easier to fit in smaller spaces |
|
Low Frequency Response |
48 Hz
vs
60 Hz
|
Generates deeper bass |
 High Frequency Response |
22k Hz
vs
17k Hz
|
Generates higher frequency |
 Base Surface Area |
1128cm2
vs
2828cm2
|
Takes less floor space |
 Price per pair* |
7999USD
vs
35999USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
ATC SCM150PSL |
ATC SCM40 |
| Brand |
ATC |
ATC |
| Speaker Type |
Floor-standing speaker |
Floor-standing speaker |
| Power Range |
100 to 1500 Watts watts |
75 to 300 Watts watts |
| Sensitivity |
91 dB |
85 dB |
| Impedance |
8 ohms |
8 ohms |
| Frequency Response |
60-17k Hz |
48-22k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
14.76" |
6.46" |
| Woofer Composition |
|
|
| Tweeter Size |
0.98" |
0.98" |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
2.95" |
2.95" |
| Crossover Frequency |
380Hz & 3.5kHz |
380Hz & 3.5kHz |
Physical Specs |
|
|
| Height |
884.0mm (34.8") |
980.0mm (38.6") |
| Width |
498.0mm (19.6") |
370.0mm (14.6") |
| Depth |
568.0mm (22.4") |
305.0mm (12") |
| Weight |
67.20kg (147.8lbs) |
31.00kg (68.2lbs) |
| Enclosure |
Sealed |
Sealed |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
|
|
| Labor Warranty |
|
|
These sit in different price classes - ATC SCM150PSL costs roughly 4.5x what ATC SCM40 does. Expect it to lead on paper; the question is whether the gap is audible enough in your room to be worth it.
| Area | Better | Why |
|---|
| Bass | B | ATC SCM40 digs deeper - 48Hz against 60Hz. |
| Amplifier needs | A | ATC SCM150PSL is more sensitive (91dB vs 85dB), so it goes louder on the same amplifier. |
| Headroom | A | ATC SCM150PSL takes more power (1500W vs 300W) - more in hand in a big room. |
| Size | depends | ATC SCM40 is easier to place; ATC SCM150PSL is bigger, which usually goes with fuller bass. Your room decides. |
| Price | B | ATC SCM40 is cheaper - $7,999 against $35,999, about 78% less; arguably a different class. |
A ATC SCM150PSL B ATC SCM40
depends neither is better in the abstract - it turns on your room, your system or how you will use them. Only specs published for both speakers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
ATC SCM150PSL is ahead, but only on 1 of the measured areas, and it costs about 4.5x the price. That is a lot of money for a narrow margin on paper - ATC SCM40 looks like the sensible buy unless something else about the ATC SCM150PSL appeals to you. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 60Hz anyway, so judge these on the other rows instead. In a large or open-plan room, ATC SCM150PSL has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, ATC SCM40 is the easier speaker to get right.
And remember what a spec sheet cannot show: how each looks in your room and whether the finish suits it, what dealer support and warranty are like where you live, and how they actually sound to you. If you can hear them first - ideally with your own music - that will tell you more than any number above.