I'm having a hard time correlating the 60-22khz freq resp +/-3db to it's Graph. According to the graph, it looks like there is a 11 db drop from about 17khz to 20khz (From 90db to 79db).

It has been said that that drop is an anomoly of the equipment(?) used for measuring, or something to that effect.

hummm.. that's a good question for Alan !!

Cat,

Response up there (15 kHz to 20 kHz) simply doesn't matter. There is no musical information of any consequence for any musical instrument in that region ; it won't affect or change your judgement of the "sound" of a speaker, and you'd have to be a child or teen-ager to even hear frequencies that high.

"It's all in the midrange" is a bit of an exaggeration, but our judgment of a speaker's sound quality is largely confined to the spectral balance of the mids and upper mids (to about 8 kHz) and the bass extension and balance relative to the midrange.

Regards,
Alan

Ok, thanks. Someone on avsforum.com was wanting advice concerning using either M22's or Aperion 5T as surrounds. Says he couldn't use the QS series because of placement in his columns. When I compared the freq chart of the 2 speakers, the Aperion didn't have any drop in the 17k-20k range. Now I'm wondering if this is indeed correct, or Asperion is mis-representing their product, because if it was that easy to do with a single tweeter, it seems that Axiom would have a frequency graph like theirs also.

Aperion clicky

1) Specs & Features tab, then
2) Download graph clicker is near the bottom.

Brian, in addition to Alan's comments about the lack of significance at those very high frequencies, the measurements are also subject to extreme swings with small changes in position. For example, look at the current Axiom graphs for the M3 and M80, which use a "listening window" measurement over some unspecified range of angles. The averaged response at the top doesn't show that drop, and this certainly would also apply to the M22 and other Axiom speakers using that same tweeter if their listening window was shown. Presumably the M22 Axiom spec is based on some averaged number rather than simply the on-axis anechoic measurement.

I do notice that the graphs that have this high frequency drop have a more wavier line than those that don't, but that drop is still too deep to not be there with the more averaged graph with the smoother line. This leads me to believe that the M50, M2 and M22 have a diminished high end, yet mostly inaudible, but the M60, M3, M80 does not. If it's using the same drivers, I have a hard time understanding why the difference.

Granted this is a M22ti but the various individual measurements and averaged measurement can be seen here for comparison:

http://www.soundstagemagazine.com/measurements/axiom_m22ti_se/

Ok. What I get out of this is when off axis listening is included in the calculations, it drags the high end freq resp down a bit, which only makes sense.

The graphs for the M50, M2, M22 might include the off-axis numbers, but it doesn't say. I can only assume that it does.

Brian, if you're referring to the current M50, M22 and M2 Axiom graphs, no, they aren't "listening window" measurements, they're on-axis. Just as the M3 and M80 listening windows at those frequencies are essentially identical to each other, certainly the other speakers would be as well when measured in that way. The listening window(over some small angle)measurement doesn't "drag down" the high frequency numbers, but on the contrary, evens them out.