ATC active vs. passive

hi @ei001h

There are some dealers in the north east with 50s, so you need to call the main Lone Mountain office in Las Vegas for more specific info or look up the website.

Now to answer your question, comparing 40 to 50, the big picture idea is ATC focuses on low distortion drivers across all models as bandwidth gets larger. Then ATC explores the entire active vs passive issue with passive and active versions of nearly all models (like the 40 you mention and the models below in price and size and models above).

Most ATC models sounds quite similar and are classed by dynamic range capability and resolution as well as bandwidth. This means you can select a model based on what’s best for the budget, room size, SPL requirements, low end requirements, dynamic requirements, etc. So ATC doesn’t do the "larger/more expensive is always better" thing like most companies do.

Active gains you more resolution, better imaging and lower total system cost (you get 3 amps in each speaker as part of the active package that are all big linear power supply and low distortion Class AB designs). This enables phase adjustments and other things internally that you cannot do in passive system- no matter how good the amp is in said passive system (even ATC passive). In active, colors of the amplifiers and sources shine through more than in passive system due to the lower distortion nature of the design and removal of the masking distortion left behind by a passive crossover and cabling. If you are a tube lover, I recommend you get a great tube preamp-it will definitely sound like a tube system. Active reveals more about cabling, phono stages, cartridges, CD players- everything in front of the amplifiers/speakers. All of these values are really choices for you to make and not all of these values appeal to everyone. For example, if you are in a 10x12 room, this extra bass may not be worth it (a 10x12 room cannot support much below 55Hz or so). The "clearer below 720" value might be worth it to you if you listen to a lot of orchestra or a lot of vocals or piano and could be more important to you and this would mean you don't need a larger speaker. If you are an acoustic guitar fan and like that type of music, spending money on getting lots of deep low end by going larger may not pay off for you.  Then something like the 20 might be better, small , lower cost, but still supere resolution.

So if those values of more low end, clearer lower midrange and bass and better dynamics attract you, then investigating the larger ATC models like the 50 would be a good idea. If not, the 40 is a great speaker in both passive and active forms. The sound would definitely be very similar between them.

Brad

Lone Mountain

ATC Importer to the US 

As I’ve mentioned in another thread long ago, I have done a very close active vs passive comparison at a trade show - same speakers, ATC amps for passive system run passively biamped, active using the internal amps with the same output devices and design in both active and passive.. The power available in both systems was roughly equal. The active system exhibited much bette imaging and better high resolution of fine details like room sound, reverb tails, harmonics on piano, acoustic guitar, violins. I offered visitors to the room a choice to pick and not everyone picked the active - although I couldn’t understand how they couldn’t hear those improvements.

One note - the comment about amps not lasting a long time inside the speaker is simply not true - unless it’s crap amp. They are in their own separate enclosure even inside the speaker and there is no shared space. Also all ATC is class A/B, not class D. That being said, we regular service active speakers that are still working after 30+years! Many studios use them 24/7 for 10-20 years. With 6year warranty we see very little failure.

brad

@ei001h 1. is it possible to self modify Active into passive down the line if get tired of active and would like to try other amps ?  Is it possible to purchase passive crossover and swap them at home? 

NO this is not possible due to the calibration necessary to set individual driver loves to build cohesive anaphase linear system.  Theoretically you could purchase an ATC passive crossover (for the model you have). Installing it would not be something to do at home.  You'd have to remove most of the drivers to get inside the box. 

2. 150 is considerably wider baffle than 50. How does this affect the imaging and the ability to disappear. Logically, 150s should be much harder to disappear.  The wider baffle is of course to fit an 15 instead of a 9 inch woofer.   The waveguide on the midrange and tweeter do not allow the drivers to depend on the baffle for pattern control;  the dispersion pattern from these drivers is less than 180 degrees.   I have heard the 150s sound as good as 50s but with more low end due to the larger woofer.  Doug Sax, mastering engineer extraordinaire, (now passed) used 150s installed in a soffit to get the ideal, bass is now working into half space instead of full space. So no I don't think this baffle width is a major factor in comparing these two models (although I will ask engineering about it).  In 20_ years I have never had anyone note this or say they can hear this difference.  Rooms are such a major factor influencing imaging and the ability of the  speaker to disappear.  1st reflection problems can dramatically affect this aspect of speaker performance.         

@ei001h 

Do your SCM 40s have tweeters that sat "ATC" engaged right in the metal flange around them?  If it doesn't, these are the older SEAS tweeters used in the SCM40 Mk1's , while the newer SCM 40 Mk2's use the ATC hand made tweeter introduced in 2017-2018 or so. Now ATC is using only their own tweeter in everything

Brad.