Hi,
merlin said:
Just to add that the ATC measurements refer to the domestic anniversary model, which subjectively sounds somewhat different to the regular studio unit (I have now heard both at length).
The anniversary employs completely different amplifier and crossover topologies as well as a totally different cabinet design.
It would be interesting to find out if the Studio series measures the same, and if so, why the substantial sonic differences don't you think?
It is my understanding that while the actual amplifier circuitry may be different, the actual crossover frequencies and slopes are the same, as are the drivers. So key measured features (distortion, directivity and most likely frequency response) should be the same.
As I subscribe to the notion that even if two Amplifiers measure identical according to traditional (THD, IMD @ xxxWpower and identical frequency response) significant sonic differences can exist this and the cabinet changes may account for the differences.
I had previously seen ATC measurements (not as complete as in HFN though) which I remember having the same rather distinct Frequency response shape, this was a larger studio model.
It may be interesting to some if I where to provide a partial discussion at least of what I feel the subjective results of the measured performance of the ATC SCM50 DOMESTIC ANNIVERSARY EDITION may be, based on the measured response.
First, the distinct frequency response curve with a slightly emphasised LF and HF (both having a boost relative to the "average" 500Hz-5KHz SPL) strong depressions in the 500Hz and 4.5KHz range (the fundamental and presence ranges respectively) will have together with the rapid treble rolloff off axis the effect to make the speaker sound detailed (due to the emphasis on the formants over fundamental tones) without subjective forwardness or edginess at high volume (due to the upper midrange depression) but somewhat lacking in presence at lower volumes and comparably less than ideal vocal intelligibility, made worse by the poor directivity conrtol of the speaker at midrange and lower frequencies, unless the room is extensively treated acoustically.
The strong off axis treble rolloff will lead in room to a fairly "warm" balance which may be, together with the upper midrange depression, required to offset the effects of the rather high midrange and treble distortion (especially that of dissonant "odd order" harmonics). This distortion in turn will make the Speaker sound subjectively louder than it is actually playing but also lends an edginess that may require the offseting frequency response alterations to balance out, I call this (for obvious reasons) the Aphex Effect.
The LF response peaking and relative LF Q derivable from the plots and the high levels of LF distortion would suggest a speaker majoring in what people call "PRAT", always found in a certain midbass emphasis combined with some attenuation of really low frequencies and fairly high LF distortion (which is why most competently designed SET's readily out-PRAT Naim - call it the "Maxx-Bass effect" if you will).
It certainly is in my view an interesting blend of using one weakness to conceal another, but it is rather far from traditional accuracy, note that the writing is based strictly on interpreting the measurements and deriving expectations from them, though my ears do agree largely with "what these speakers should sound like based on measurements".
As somone who speaks english as third or fourth language, rather than natively I tend to focus on some areas few native english speakers would, vocal intelligibility is one, as completely and correctly understanding the sung english lyrics often remains difficult for me (a problem I do not have with even the thickest german dialect!), so it is an area where I focus and where ATC is particulary lacking, also the "Aphex Effect" really gets on my nerves quickly, I have a very low tolercance for this, while many may actually percieve this as an "enhancement" of sound.
Anyway, so much on bringing the correlation of measured and subjective performance together and on what I hear.
I have my asbestos suit on, so feel free to flame away.
Ciao T