ATC SCM50 measured performance vs. high quality studio monitors

Bub,

I am not knocking them at all. I like them a great deal.

All loudspeakers, whether they be ATC's, Quads, Merlins or giant Tannoys, are a set of compromises. I am merely pointing out ATC's in light of the topic.

ATC's communicate a variety of forms of music very well indeed but there are others where they are found wanting and exposed by other designs. I now have the SCM50's on the factory stands and am afraid I have to say that this is optimal in terms of height from an accuracy point of view. So please don't claim the sub optimal dem position on this occasion.

And yes I can happily criticise the Quads for their woeful dynamic headroom, their appalling dispertion characteristics, and their unreliability. They are far from perfect. As I said, no such loudspeaker exists.

 

I wouldn't dream of commenting on your system without hearing it first. I bet it sounds great.

ATC remain the best I've heard, is all. Considering that they only cost me £4k, I think they are unbeatable at anything near that money.

 

Change of heart, you commented on mine last year.

Shame the thread was deleted.

 

I'd agree Bub. I'd say that for the majority of listeners, the ATC's stand comparison with speaker/amp combinations retailing at double their price. Bargains.

 

Even at new prices, I think that is true.

 

Thats over egging the pudding a little bit.

You made comments on mine as well bub - never even having heard a single component let alone the whole system!

 

Ah yes, but when everyone on the internet bar you says that PMC speakers are very poor, who am I to believe?

 

Another example of pudding egging. Its only you and merlin. And you havent even heard them (and I suspect Merlin only heard them at a show ;-)). This thread is about atc not pmc bub. Start a new one if you want to discuss them.

 

One of my clients is a main PMC dealer across the South East so you could say I have had more than enough exposure to them. I did not factor them into my short list this time. The new B&W 802D are quite good though, should you want to get an alternative reference.

 

Under what conditions?

Are they a big improvement over the 800/801/802? I heard the original N800. Out of all the speakers I listened to in the mb2 price range it was the worst - I was very surprised.

 

Yes they are a big improvement.

 

In what way?

So you heard the pmcs at shows at which this distributor was present?

 

Hi,

Try it with foreign language songs. Honestly.

Yes, to me even pure acoustic recordings sound heavily processed on ATC's, as I said, I'd call it the use of "MaxxBass" and "Aphex".

Disagree all you like.

Hmmm, around 4 point something percent 2nd and 3 point something 3rd for 90db/1m @ 40Hz? And you call that "good"? I call that (without all the tedium of converting percent to absolute and sumsquare addition etc to get THD) eyeballadded 5% THD or -26db. I don't have the Mag at hand, but 50Hz was not much better.

Now we have a problem, the only current publication that actually publishes distortion measurements for speakers is soundstage, courtesy of the NRC (used to be Floyd Toole's gig) and they measure 50Hz - 10Khz and at 90db/2m, which as everyone (who passed acoustics 101 anyway) knows translates into 96db/1m.

So we have a measurement of 96db/1m/50Hz compared to one at 90db/1m/40Hz.

Given is that at low frequencies the excursion of the driver increases lineary with SPL and quadruples for each and every drop of frequency by one octave> Given is also that at low frequencies the 2nd & 3rd HD (and thus THD&N/S) are directly and lineary related to excursion. These givens can be found in the common literature on the subject.

Considering all that is given I would suggest that 50Hz/96db/1m is more stressing on the driver than 40Hz/90db/1m, being in terms of driver excursion equal to 35Hz/90db/1m and that if a speaker can equal a THD&N/S of -26db or better at 50Hz/96db/1m it will very likely have a lower or at the very least comparable level of distortion than the ATC SCM50 DOMESTIC ANIVERSARY EDITION at 40Hz/90db/1m.

I must state the assumptions made, anyone with sufficient acoustic background should be able to confirm these.

I would add that the NRC measurements also show the midrange and treble distortion up to 1KHz at 96db/1m, where HFN measured around 1% for the ATC SCM50 DOMESTIC ANIVERSARY EDITION. So any speaker showing a level of distortion of better than -40db @ 90db/2m will have materially lower levels of distortion than the ATC SCM50 DOMESTIC ANIVERSARY EDITION.

Now on to domestic loudspeakers that should equal or better the ATC SCM50 DOMESTIC ANIVERSARY EDITION in terms of distortion for both low frequencies and midrange treble, based on the assumptions stated above:

Dynaudio Confidence C4 Loudspeakers: Measurements

Paradigm Reference Studio 100 v.3 Loudspeakers: Measurements

Paradigm Reference Signature S8 Loudspeakers: Measurements

Wilson Audio WATT/Puppy 7 Loudspeakers: Measurements

Dynaudio Audience 80 Loudspeakers: Measurements

Wilson Audio Sophia Loudspeakers: Measurements

Note that list above contains quite inexpensive speakers (Paradigm, Dynaudio Audience 80) together with boutique fair (Wilson, Dynaudio Confidence), but all are large floorstanders (what did you expect).

I guess the closest relation to the SCM50 in the field is the Wilson Sophia (3-Way, 10" Ported woofer) which with a good amp will draw about level with the ATC on price and which shows around 6db lower LF distortion and baring two narrow spikes very little distortion at all 96db/1m above 100Hz. Even at 101db/1m distortion, excepting two spikes around 500Hz & 1KHz remains around 0.5% above 100Hz with 50Hz-10KHz @ 101db/1m below 3% THD at all frequencies in the range covered.

To better this you do need to get a MEG RL900/901, K+H O500 (both similar price as ATC SCM50 and also active), Tannoy System 15/215DMT (the System 15 lists at a very reasonable £1,800/pair, the 215 around £ 3,000/pair but are passive) or Meyer X-10 (I am sure others apply, I prefer to talk about that which I know).

Frequency response both on axis and over the listening window is pretty decent too and all that precludes the Sophia from recommendation as mid/far-field monitor is poor dispersion control. It is expensive, admittedly, but just the Wilson Watt/Puppy appears to deliver what ATC promise (yes, I'm a closet Wilson fan, I liked their older speakers better, more studio monitor like, less HiFi).

What the SCM50 sounds nearfield is quite irelevant in both domestic settings (where few people are likely to listen to large speakers in the nearfield) and in studio settings (where the SCM50 and larger are clearly mid-field to far-field monitors).

And I might add that their near complete lack of dispersion control makes them particulary difficult to deploy in the mid & far field.

Completely agreed.

I do not feel this to be the case. ATC claims to make the most accurate monitors avaiable. In terms of freqency response flatness, distortion and dispersion control they are quite clearly significantly worse (distortion > 12db, dispersion control is better not mentioned, response flatness barely acceptable) than a significant number of other state of the art studio monitors and many quite ordinary domestic speakers.

Ciao T

 

Hi,

Just heard them at a dealers dem with a full dCS Purcell/Elgar and Classe Amp in front. Deeply disappointing, but no idea where the fault lies.

Given the arrangement the rather poor dispersion control of the B&W's did not matter, maybe it was the CD release of "Prezel logic" over vinyl that made the sound boring to the point of loosing interest (quite an achievement for one of my more favourite Albums)?

PMC, well the bass is okay, the midrange passable, the treble rather bad.

Did a custom job for a friends studio where we kicked the soft dome tweeters out for old style Focal TC-120tdx and triamplified the whole shooting match using valve amp's on the mids and treble, Krells on woofers plus a modified BSS digital crossover (that was around the time when they where more or less the only game in town) to drive the shooting match.

Set up right, drivers time-aligned via the BSS and equalised plus sensible X-Over points and this system rocked both in terms of measured performance and sound, really clean impulse response, nice flat frequency response and pretty decently low distortion, if nothing to write home about. Sounded good even quite a bit off the hot seat. I think he still uses the setup unchanged....

Ciao T

 

Thats a bit tough on the pmc - which ones did you hear? I would have said the midrange was the outstanding part of the package - far better than atc. However I would restrict my comments totally to the pmc three ways. It has to be triamped to sound any good - which is what I have done in my setup. Perhaps I can soften your outlook a little if you hear my system ;-)

 

Mr Fruitcake.

Do you have some sort of problem with ATC? If so, why not take it up with the company direct? There's very little anyone here can do to help you, other than offer sympathy.

Meantime, ATCs continue to be used in the prestigious studios....

 

Hi,

The ones we worked on where early BB5 with that bass extender.

My friend felt the need to have work done after he heard a 300B SE Amp driving Beauhorn Virtuos (plus Visaton supertweeters and subwoofers - more or less the same system as reviewed by me for ETM) and found he could hear miles more of his own recordings than with his own system.

The more current ones I hear still only rate "passable" (as in "par for the course, not exceptional"). But I suspect I am listening to other aspects of the recording/performance than most people.

Ciao T

 

Bub, please stop the "mr fruitcake'' business. Its a definate breach of forum AUP.

 

Apologies to any fruitcakes who were offended.