ATC SCM40A Active floor-standers - A film about

In this film review about ATC's SCM40A Active floor-standing speakers, appraised in my article on my website, they may not be active enough to be going anywhere under their 36kg weight, but in HiFi terms these are Active speakers with a capital A.
Have a look at my website here www.13thnote.net/
Or prefer to read the article - have a look here ; www.13thnote.n...
Or find out about what are the differences between Active and Passive speakers and crossovers www.13thnote.n...
Or the difference between different amplifier classes here ;www.13thnote.n...
Or read ATC's explanation on their website here -atcloudspeakers...
Thanks for watching and if you like what I do, please subscribe for more balanced and credible HiFi reviewing!!
#audiophile #loudspeakers #atc

[@marcelocendoya5486]

Excelent product description and a very honest review. It is very little or nothing to criticize. This ATC model is very close to the ideal home loudspeaker.

[@antonchigurh4125]

Good stuff, gorgeous speakers and great review. I could have happily listened to you discussing these for another ten minutes :) I'm a huge fan of ATC speakers and their reputation for serving up sublime midrange in spades is well deserved. I can't speak for the actives, but having owned some passive scm 40s my only criticism of them was that if you fed them garbage, they gave you garbage: ruthlessly neutral speakers (which is in some ways a compliment). Thanks for posting and keep up the good work.

[@13thnotehifireviews7]

Anton Chigurgh thanks Anton. That’s great to know about the timespan. I’d love to go longer sometimes, but editing well and in an engaging way kind of limits things. I totally agree about your comments re bad in bad out with these speakers. Thanks again for feedback!

[@freezerburn6454]

I have ATC CA2 mkii preamp and ATC P2 amplifier, I'm thinking about the ATC40 passives, but I'm also wondering if trading the P2 in toward the actives is worth it. I assume some increase in quality, but also could I just get passive and be as happy.

[@tonesbones502]

Haha, what you said at 12mins is so true and exactly the advice I would give any music enthusiast just getting into hifi. If you can afford these speakers just stretch yourself and get them (or the passive ones as long as you have a very good amp or two), because the journey you will take to get to this point is going to cost time and money. If its all about the music then listen to this advice, you simply wont find better, especially at this price. And a pair of speakers of this quality (as long as you keep them dry) will last you a life time. The only thing I'll add here is don't be afraid of integrating a quality sub. If you can tune it all the better.

[@abboberg]

Darko Audio said that being an audiophile is a journey, with the "fun" of always having to upgrade. I did the opposite, after a decades-long hiatus from hifi. I spent a few weeks doing my research, then landed on the Adam Audio S3V monitors (got a killer deal on them at a local Guitar Center) back in April 2022. Ever since then, I've been watching all the "journey" videos, subscribing to many audio channels, just to affirm if I made the right decision and wasn't too rash (after all, there are hundreds of speaker manufactures out there). I can now say that I saved a lot of money and headaches, and perhaps had a little luck on landing on these awesome speakers from the start. Also, there is no "junk" between the speakers - just our fireplace, which keeps the wife happy. I have a DAC underneath one of the speakers mounted in the stand, and a cable running from the sofa to the DAC, which I hook my smartphone up to. It's a great feeling to have a 21st century upgrade in audio!

[@SpacialObjects]

Surely those red poles are spacers to prevent people shoving the speakers hard up against the wall and blocking ventilation for the heat sink?

[@TheManunderwater]

Utterly brilliant review. Rational and clear and you made the important point that you're getting the amps "free"! Also the amps will have been tweaked by. ATC to match their speakers. I'll be buying these later this year....

[@keeperofthereign]

My dream speaker mate, although beyond my financial ability right now! Many many thanks for the review!

[@13thnotehifireviews7]

keeperofthereign no worries, glad you liked it. They were very good.

[@jeevanmotors4275]

Hi" This is Charles Presently IAM Using old Generation Passive SCM40" So if i upgrade to New Active Scm40 will Shows Tremendous Difference or Just Marginal Difference

[@13thnotehifireviews7]

Jeevan Motors can’t answer as I haven’t tried, but I think you will prob hear a big diff

[@nespressoman]

I was going to buy a pair of the active ATCs last year. Unfortunately I could not get enough for trading in my existing speakers. One day, I hope.

[@Crannie3]

Nice review format, found this as I considering upgrading from my SCM19's to the 40A's. As a review I world be interested in the NAD C658 as and all in one source: streamer DAC Pre. I'm told the ATC actives live a low impedance output from the Pre of 300 ohms or less. Keen to hear your opinion of the NAD regardless.

[@stephengarratt5076]

Following the failure of the un replaceable mid range units on my Ruark Crusader II Speakers, a good audiophile friend and ATC owner pointed me in the direction of the ATC SCM40 passives. Now in my autumn years and after a lifetime of Audio system ownership, I have discovered audio Nirvana! My ATCs are Tri-Amped with with a pair of 1990s Audiolab 125 watt 8000Ms for the Tweeter and Mid Range and an Audiolab 8300MB 250 watt for the Bass. The preamp is the Audiolab 8000Q (late 90s) Everyone who has heard these wonders is absolutely stunned by what they are hearing and I am just saddened that I had not purchased these speakers sooner! The clarity and reality of music played, is out of this world and the beautiful bass response seems to go much lower than the specification. My listening room is a modest 12 x 13 foot but the ATCs do not overwhelm at all, the sealed box design cancels any unwanted booming, the Bass being well controlled, but when it’s there you know it. Definitely one of my best Audio purchases of all time!

[@13thnotehifireviews7]

Good one, enjoy!

[@stephengarratt5076]

@@13thnotehifireviews7 The only glitch which I experienced was a year ago when one of the Bass units started to fail, an ominous slight rattle when playing a certain Organ CD, fourth movement of Widor’s Organ Symphony No.5 showed this up. The dealer Orange and Lemons from Clapham picked up the speaker and replaced the faulty unit and since then, no problem.

[@13thnotehifireviews7]

I liked the atc sound but I think you need a really good room set up with the flat response. My room is a little small and so I prefer a smaller floorstander and one with a little bit more treble then ATCs. That’s not to say it isn’t a fantastic speaker with the amount of realistic timbral information going on.

[@stephengarratt5076]

@@13thnotehifireviews7 The only problem, if you can call it that, is the brutal honesty of the speaker, you play a sub standard recording and it will sound just that and more. Play for example a half speed mastered vinyl disc such as Peter Gabriel’s So or any of the recent Tony Visconti David Bowie reworkings and the SCM40s just sing! Play the 2018 so called CD remasters of Curved Air’s first three albums and the over the top compression and digital clipping sounds dreadful.

[@mikemcguinness1304]

​@13thnotehifireviews7 can I ask what are the dimensions of your listening room , did you have any boom or room modes

[@stevebendelack3935]

BRILLIANT REVIEW!As you say for premium sound they are a bargain.!

[@tomhirschel8524]

JBL 4367 . Well worth looking at. They need more than 200 watts to drive them properly. The active version is the M2.

[@Thomas-us4wq]

Hi Sir.. My suggestion for at product to review is a pair of Audio Note E Speakers. They were highly regarded some years ago now, but are they still worth it? Who do they compare to more modern equipment?

[@roberthague3062]

How do these compare to similar active speakers like Meridian 5200SE?

[@user-ys4og2vv8k]

Which would you choose between these and the KEF LS60?

[@marcmoehlig7655]

Excellent review! Would be nice if you could review the new Volumio Primo DAC and the Rivo streamer.

[@Romulus980]

My dream speaker, I would like to know more about the different preamps one can use, especially solid or tube preamps as I believe can adjust the flavour of the sound?

[@AllboroLCD]

As far as preamps go, and basing your budget off the price of the ATC speakers, your best "all around" bet would be for the PS Audio Stellar preamp. Its solid state and has an incredible DAC built in. If you insist on tubes, go for the Rouge Audio RP-1. Both of these units retail at around $1600, and feature an IR remote control, something not commonly found in hi-end preamps. Both companies are revered amongst the audiophile community and the chances of dissatisfaction are exremely slim!

[@tthedon2471]

are they kept on all the time?

[@13thnotehifireviews7]

On off button on each

[@huangjin800]

How does the actives compare with the passives ATC SCM40 driven by the SIA 150 integrated amp?

[@13thnotehifireviews7]

Haven't tried tbh, but I think ATC regard the active version as better because of all the benefits you get with an active crossover. I prefer a speaker a bit more incisive as you need really good rooms to make these shine I feel.

[@huangjin800]

Thanks for the very prompt heads up. I was thinking of getting the SIA 150 coupled with the SCM 40's. The alternative would be to purchase the actives and a separate preamp which would be more expensive. I also don't like the idea of amplifiers integrated with the speakers. B&O also use active speakers and they are even more expensive. My concern is that it seems that one needs to play the ATC speakers loud. I live in an apartment and I am not into playing music loud. Just wish for crystal clarity in my jazz, classical and easy listening music.

[@13thnotehifireviews7]

@@huangjin800 you shouldn’t be concerned about amplifiers in speakers , it is often always the much better design. See my article on active speakers on my website if you read the atc review there are links to it. You don’t have to use massively expensive pre amps with these speakers. They are very responsive to the pre amp but still work really well.

[@huangjin800]

@@13thnotehifireviews7 Thank you for your kind reply. I will read your article. Although it is noted that to do these speakers justice they should be played loud; something I am not keen on doing.

[@13thnotehifireviews7]

@@huangjin800 I didn’t find playing loud was a pre requisite for good sound at all.

[@bachbaby6996]

I have a passive pair in matte black and absolutely love them.

[@TombstoneTube]

How do they sound at lower volumes? Thanks

[@13thnotehifireviews7]

I thought they are ok, but like most speakers they perform better when you turn it up

[@goldenears9748]

Brilliant again, Could you please review the Naim Uniti Nova with your own speakers as I have the same pair and it really deserves your attention. There are no good video reviews of this on KZbin and the Atom always gets the spotlight. Thanks, Simon

[@13thnotehifireviews7]

GoldenEars Thanks for your nice comments again. Naim are a difficult firm to deal with and unfortunately they ignore all but the very established magazines where they know the review will always be positive. That said I did think the Nova worked ok with pmc twenty523 when I briefly heard it together in a Sevenoaks. Not enough to say buy it because I didn’t a to b. But naim to me are one of those brands where you don’t get that much for your money. £4300 for streaming, an 80w amp doesn’t seem like vfm to me. Especially as those pmc’s love power. Instead for a bit more I’d look at the Hegel h390 or lower price/power like h190. You can run Roon off of the hegels I think and since so much of the sound is due to the quality of amp and power, it makes sense to go with most gutsy you can get. I suspect you could get a Hegel h390 at the same price as that naim and it will sound infinitely better. Maybe then add a cheap Roon server too if you’ve not done roon - I can heavily recommend. This Hegel h390 is definitely one I want to review so watch this space. Message me on my website if you want more info.

[@13thnotehifireviews7]

GoldenEars what did you think of my recommendation out of interest. Any concerns and thoughts?

[@fizywig]

@@13thnotehifireviews7 how would the bartok sound directly into these, another component you highly praised, and would that be a true 1 box solution or would a good pre amp such as atc s pre amp boost sq, and still be becessary cos the bartok pre amp is only so so?

[@softbingan]

Where I can find the sound track

[@Phastm3]

Nice video. I had a pair of scm11V2’s and they were great speakers. I will come back to ATC one day soon

[@13thnotehifireviews7]

Tom Peluso thanks Tom, really appreciate feedback. Cheers Simon

[@richarddegannes2928]

Hello, I am thinking of getting a pair of ATC speakers either ATC SCM50 or 100 ASLT. Please advise what would be the difference between the 50 and 100 ASLT? What pre-amplifier would you recommend ? Thanks.

[@13thnotehifireviews7]

Richard De Gannes really don’t know tbh as I’m not ATC and just reviewed one speaker , best to ask them.

[@all2088]

Hello Richard. If you have a chance go straight for 100ASL or even 150ASL. I auditioned 50ASL and considered to purchase a pair. A friend of mine got 50ASLT but very soon upgraded to 100ASLT. In terms of dynamics, both are excellent, but you may miss a bit of bottom end with the 50 and may decide to add a sub later. Don't let the size of 100's to fool you, they don't need a huge listening space (most of the studios using either 100 or 150 are rather small in size), moreover, 100's may perform better than 50's when you need to play them at a lower volume. In any case, you can't go wrong with ATC. Regarding the pre-amplifier, I auditioned with the Audio Research LS27 tube preamp, I was very satisfied with the result. I hope that helps.

[@richarddegannes2928]

@@all2088 Thanks for reaching out. My listening space is 19 ft long x 13 ft wide. I would like to get the 100 ASLT (Active) with the ATC SCA2 Pre-amp. Do you think that Active speakers can be used for Home Hifi. I read where they said that ATC speakers are very neutral speakers, what are your thoughts on this set up and how do you think it will sound. Thanks.

[@richarddegannes2928]

@@all2088 Do you have an email adress to reach out? Thanks.

[@all2088]

@@richarddegannes2928 Hi Richard, sorry for my late response. Personally, I would suggest going for an active version of ATC. Apart from saving on power amps and interconnects, the major benefit is their ability to play any genre of music equally well. There are few very good demos on KZbin, for example, kzbin.info/www/bejne/a57aaqqgqqqSbM0. They have few videos with both active and passive versions to compare. Obviously, ATC pre would be the logical choice, unfortunately, I didn't audition ATC with their own preamp, but you have a variety of preamps with XLR inputs to try or even a DAC with line outputs like FCS for example Bartok. You can also check the following system as a sort of reference: instagram.com/edmund_vinyl?igshid=11uez1mecpyau

[@kenjames246]

I'd love to know what you think of the passive version of these in your system for those of us that already have amplifiers.

[@13thnotehifireviews7]

I think they, atc, rate the active version more. The only thing is when trying other speakers and particularly room correction kit, these don’t quite have the flexibility and adjustability of some gear with such a flat frequency response. You really need such a good room to use them.

[@phx2jrl1]

Thanks for the detailed explanations and education.

[@szjoin992]

I'm confused: while I'm fascinated by the many excellent reviews these speakers get, there's one thing I just can't comprehend: speakers of that size that don't go below 48Hz (-6dB): isn't it strange that can't these speakers go where often even high-quality bookshelves (and most floorstanding competition) can? Am I right when I say that these low frequencies are necessary for good sound reproduction? Am I now referring to the 'pink elephant in the room'? Given the excellent performance, does this observation weigh heavily?

[@13thnotehifireviews7]

I think you have to weigh these speakers up on lots of things other than treble response. Things like integration of drivers and authority etc. They are excellent speakers although personally I prefer speakers which have more treble - the PMC twenty5 23i speakers with a Hegel H390 would be superb for me.

[@rogermatthews2760]

It’s what subwoofers are for.

[@TheManunderwater]

@@rogermatthews2760 I'm confused (and always have been) . Why do subwoofers not have to match the "main" speakers? To me this seems perverse and illogical. Matching the same manufacturer's subwoofer to their speakers seems a no-brainer?

[@13thnotehifireviews7]

That’s what I thought. Trying a rel sub atm. Another way is matching the sub with the main amp with high level connection - running off speaker terminals and not rca output of amp.

[@rogermatthews2760]

@@TheManunderwater When possible, there is a case to be made for using the same brand main and subs, if only because the manufacturer has developed them to work together. Yet, the vast majority of sub owners aren't using the same brands as the main -- and not talking about problems doing that (presumably they would). Are they all "perverse and illogical" fools? That's the question it would have been better to research and think about before posting. I won't claim to know all the reasons why, but one obvious hypothesis is that at least in most cases our hearing is not sensitive enough to pick up any low end discontinuities. This would be all the more the case when the main speakers are allowed to run full range and the subs come in only within a very limited range, e.g., ~44 Hz with my 40A's. In that case, the two are cross pollinating so to speak, their differences effectively impossible to tell apart.

[@cp070476]

I was lucky enough to pick up some passive SCM100's 6 years ago. £3,500! best purchase i made they sound excellent.

[@matldn2697]

Where????

[@cp070476]

@@matldn2697 Ebay. UK

[@matldn2697]

@@cp070476 fortunate.

[@cp070476]

@@matldn2697 I had SCM 40's before. They have really gone up in price £3200?. I paid £1500 in 2012

[@matldn2697]

@@cp070476 True, but I am looking at Wilmslow audio, as there are some amazing speakers there. Also I am thinking of using a Chord 1200C power amp.

[@carolineleonard8214]

Hi Simon. I've been following and enjoying your posts since you started and thoroughly enjoy your posts and their validity. I'm considering going down the route of these actives, providing that I can get an audition anywhere close to me in Wales. May I ask if you had your Hegel when you reviewed these? (Coming from the preamp out of course). My reason being that I want to get the full Hegel, with a P20/30, v10 and DAC if I can get hold of one. Looking forward to your reply I thank you again.

[@13thnotehifireviews7]

Thank you Caroline. I didn’t have Hegel then tbh, obviously these are actives . I’m offering advice on patreon or PayPal as I need to make this work. Links in latest vids. Best wishes Simon

[@MichaelPsyrras]

Nice review!!! Did you use a preamp with the RME or not? Do you have any comments about the RME directly in to the 40A vs using a preamp? Thank you!

[@13thnotehifireviews7]

Thanks very much!!! No pre amp with the RME - straight into the ATC’s. Obviously they will benefit from much better DACs, just didn’t have anything better at the time. Ideally you’d want to use a really great pre amp straight and/or a DAC onto the ATC’s. Maybe something like a Chord DAVE which is a very good pre too. Or better still dCS Bartok. Or maybe something cheaper like a Hugo TT2 would be great too. A Bryston BP17 cubed (BP17 3) pre amp I tried was terrific and that would be what I’d try with something like the dCS if money was no object. Not to say these ATCs don’t sound terrific with a modest DAC like the RME though. I suppose it’s a question more so of getting the most out of them. They do need good space and set up too.

[@MichaelPsyrras]

@@13thnotehifireviews7 thank you for replying (so fast)! I am wondering if their cda2mkII would be a good choice (I have auditioned the combo and its great but still..) vs the ca2mkII with rme (or Qutest ? ) I am afraid that the budget is up to those dacs! Thanks again!

[@JamesH1973]

Do you think these speakers would be overkill in a small 8m2 listening room?

[@hmlai75]

It might overkill in your room .. is better to get the 19A or 20 A pro .. even SCM 7 with a good amp will really impressed you .. by the way 19A and 20A uses SL driver , while the 20A using reference tweeter same as the 50s , 100s .. 20A is a better bargain

[@jerzy1306]

i dont like to agree to often,but ths time i agree totally!thanks.

[@robertobassani]

Hi, what xlr did you use? What pre amp do you think it’s best? I just bought a pair and I need to try them with good gear to get the best out of them. Thanks in advance

[@13thnotehifireviews7]

Nothing special re xlr. Which pre amp is how long is a piece of string tbh. You might want to try ATC amplifiers as a starting point.

[@marcmoehlig7655]

Maybe the Atoll ST300 Signature Streamer-DAC-preamp? Gets excellent reviews and is relatively affordable. Dual Burr Brown DAC offers an organic quality while being detailed.

[@kubjohal]

Hi there, what equipment did you use to test - in this case source and pre amp? Cheers,

[@chihungchan8325]

how much of atc scm 40a? Thanks!

[@13thnotehifireviews7]

I think in the U.K. about £7k and approx 10k USD. Contact ATC for prices.

[@chihungchan8325]

@@13thnotehifireviews7 thankyou! what pre amp match atc40a is well?

[@fizywig]

Could I use a matrix audio element x as a standalone box streaming from Qobuz, with the XLR connections directly to these scm 40a speakers?

[@13thnotehifireviews7]

Yes because it looks like the Matrix Audio has an analogue pre amp with xlr outputs to the ATC’s xlr inputs. Personally I’d spend a bit more on upstream components to get best from these speakers, ideally. The RME I used worked well but they are responsive to the DAC and pre amp. My pick of the gear I’ve tested would be a Bryston pre amp.

[@fizywig]

13th Note HiFi Reviews Thanks for the reply I currently have the scm 40 s . Are these in a different league to the 40s ? If my budget was £12000, that’s £7000 gone on speakers leaving £5000 for pre amp, streaming dac and streaming bridge. Was thinking of the G2 AURALiC, matrix audio, as my front components but that’s a,ready £7000. Any suggestions?

[@13thnotehifireviews7]

Go on my patreon for further advice I’d say. We’ll thrash it all out

[@shemaya4979]

Are you using your Hegel H390 with ATC?

[@13thnotehifireviews7]

No not atm. Pmc, kef and monitor audio I have currently.

[@gee3883]

Thanks for the review and info Im recommending these to my bro in law cheers.

[@13thnotehifireviews7]

The new pmc twenty5 23i are much better vfm speakers imo. So bigger models in that range too. Check my vid out and subscribe....

[@gee3883]

@@13thnotehifireviews7 Cheers Ill check em out subbed earlier thanks.

[@13thnotehifireviews7]

Subscribe to Patreon too if you like, as all reviews now going on there.

[@stanmyers5994]

Excellent video, cheers mate

[@13thnotehifireviews7]

Thank you

[@thisnameisit]

Do actives make sense if you already have a good amp in your opinion?.Nice vid and nice speakers

[@willbrink]

Probably not, but "on paper" actives are always better as the amps are perfectly matched to the drivers. If i was starting over, I'd go active in a minute. As I have $ invested in a good amps, and such, I will stick with that. For the quality, sound, and the fact you don't have to buy amps, those 40A are a steal in the audio world. They cost about the same as my 803D's.

[@Canadian_Eh_I]

@@willbrink I use a DEQX and 6 channel amp and tri-amp the passives whilst dialing in the room acoustics. This setup can outerform much more expensive passive systems

[@hemantishwaran5741]

What about for a smaller room? 15 feet by 15 feet? Love ATC and big fan of actives - these could my speakers ...

[@13thnotehifireviews7]

I think you need a decent sized room

[@hemantishwaran5741]

Thanks for the advice. I’ll check out the 19A’s. Really heard good things about the SCM19v2 passives and expect even more from their active cousins

[@PS987654321PS]

@@13thnotehifireviews7 can you define what you mean by adecent sized room? What would you consider to be the ideal room size for these ATC scm40s?

[@Mik1604]

I guess using an active speaker does not allow you to use the generally recommended high level input of a subwoofer? Or do these not need a sub.

[@13thnotehifireviews7]

I’m a traditionalist in hifi and not too fond of subs. But you definitely do not need a sub with these ATC’s!

[@AllboroLCD]

I recall a time where most audio snobs scoffed at the thought of self amped home speakers, now it seems actives may very well become more common than passives!

[@uhugvjkbkjh]

V good value imo.

[@金久保宏一]

自分自身もＡＴＣー ＳＣＭ２００ＳＬＰＴをオーダーして愛用しています。日本国では既に取り扱い停止していますから、大切に使用して参ります。シリアル№９＆１０で、日本国では一組しか有りません。

[@johnsweda2999]

Don't forget when you measure you measure from the front baffle the speaker not the back of the speaker so a metre would be from the front of the speak There's no slope adjustment you can't plug it into a computer I don't know internally if there is. What is the SPL? What price can you pick them up for they're not cheap! if you're interested in selling them I might be interested South East can travel. Well how are you connecting it preamp ? Valve would be nice you should look at the kR audio p135 would be my choice would work nicely what is gutzy tho

[@13thnotehifireviews7]

John sweda I suppose that might depend on whether the cabinet interact too. Tbh that’s all academic and the point is space. Sorry these are not mine, they were from ATC and have gone back but I could put you in touch with a dealer if you email me on my website.

[@zorankalina4399]

Have pasive ATCs 40....and ATCs 7 They are realy remarkeble Only one thing can be better, actualy..they nead a lot of power....and they do not sound god...as should,if you listening them on low volumes.Somwhere...from around 30db on potentiometre....they start to sing. In any wey...will never like to change them...maybe will buy some decent pair of speakers...for lowe volume,evneng talk. Hope Wheferdale heratige Lintons ,can do that part All you mentione...keeps the wather👍🙂

[@zorankalina4399]

Thank you And for lower volumes...I add a pair of RELs T9...and a pair of RELs Tzeros But only for listening on lower levels of volume That is ... All the best from 🌞 Croatia👋

[@Billy-Spence-feet]

How has nobody else said your Paul Potts long lost twin :)

[@13thnotehifireviews7]

better get down the gym and get rid of the double chin then. lol

[@PaulSmith-qz2re]

Hello I had a pair of ATC SCM35Ss best speakers I've ever owned and then some

[@13thnotehifireviews7]

I prefer speakers with more bite. Forever how impressive Atc is they can be bland with treble

[@Roman_Ishmuratov]

Unfortunately I have not seen speakers. But I saw face!

[@13thnotehifireviews7]

Have to watch whole thing.plenty pics online too. Cheers

[@russellbaston1223]

"These bars have no purpose, they are used by ATC to lower------" so that's the purpose, and they also offer some protection to the heatsink if you might shove the speaker against a wall, while moving it.

[@13thnotehifireviews7]

Self evident….They have no purpose for the acoustic design or for us.