Sorry about not getting the ATC info but....

Hi Ben,

A big hand from me for that.

I would suggest that in the interrest of making measurements as comparable as possible with others found in various publications adopting the same protocol as NRC would be really good, this would be especially help people to make comparisons. Here is what should be included (largely extracted from the link below), especially given that you noted you will have to perform all these measurements from scratch anyway:

http://www.soundstagemagazine.com/measurements/test_loudspeakers.htm


Measurement distance 2 meters (6.5 feet)

Frequency Response and Sensitivity

Four measurements taken

1) On-axis frequency response
2) Off-axis frequency response (15 degrees horizontal)
3) Off-axis frequency response (30 degrees horizontal)
4) Off-axis frequency response (45 degrees horizontal)

Listening Window

Listening window - Averages five frequency response measurements and plots them as a single frequency response. The five frequency response measurements that are averaged for the Listening Window are: on-axis, 15 degrees left and right off-axis, 15 degrees up and down off-axis.

Total Harmonic Distortion + Noise (THD + N)

THD+N variation with frequency at 90dB - Measured at 2 meters (equivalent to 96dB at 1 meter) from 50Hz to 10kHz.

(a wider range of frequencies is desirable, as is a supplementary measurement at 96db/2m and at 102db/2m)

On top of the above I PERSONALLY would like to compression measurements, squarewave measurements between 100Hz & 12.8KHz in octave steps as well as both Impulse and Step response.

Well, if your measurements where to show an average performance one would have to at least ask how one could reconcile them with the various extraordinary claims made by ATC for it's products.

If they are "too good to be true" I would think the truth would come out quite quickly and it is VERY unadvisable for any manufacturer to provide data that is an outright lie, it may even have legal implications, so I doubt ANY reputable manufacturer would deliberatly falsify data. If a manufacturer makes sure the data is generated in standard ways and/or the exact conditions where the data applies is stated in the acompanying text I would consider such data invariably accurate, within the limits of experimental error and the experimental conditions.

As said above, if you do provide the data suggested/requested in the public domain I think it would certainly cear the air and provide a solid illustration of the truth of the very extraordinary claims made for these products.

Untill then I suspect we are left with the measurements already extant and available in the public domain, which have been discussed elsewhere.

Kind regards, Thorsten

 

Please dont bait Bub BBV. We dont want another 50 page ATC thread.

 

Fair enough - but I am betting he will be back as soon as the results are published. Lets hope so anyway!

 

Did ATC ever publish performance figures?

I've ran some distortion tests myself using both WinMLS and Soundeasy but both have different results which bring into quesion the accuracy of my measuring method. I could try re-running them again, taking screen grabs and posting them here?

I do have plenty of accurate time/amplitude based measurements taken from the DEQX should anyone want to see that. They perhaps look a little too good though since I've used the FIR filters and DRC functions of the DEQX, so the response and phase is corrected to near ideal conditions ie. +/- 0.5dB with +15/-55 degree phase variation from 150hz and up, this is in-room. Again I can defeat the profiles I've created and just measure the drivers in bypassed mode.

Its also important to note that I don't actually have any retail ATC loudspeakers but rather I use the SM75-150S and SB75-234SC drivers in a DIY effort. Obviously there will be variation between the results so I'm not sure how valid they will be in the context of assessing one of ATC's own designs and any claims they may make.

The DIY efforts are these: https://www.audio-forums.com/as-rediect/showthread.php?t=12959

Frankly I'm releaved to see some ATC hating going on, I've travelled a few well trodden forums and you rarely hear nothing but praise, including from myself. Its refreshing to see the other side of the argument and a different perspective for once. These are only speakers afterall and the measurements are important but -the- most important thing is ATC drivers do sound superb IMO, maybe I just implemented them better?

It good to see the Thorsten is still tinkering around with his quaint OB stuff and sticking firmly to his narrow perspective.