Axiom Home Page Forums General Discussion Technical Questions Speaker measurements vs. actual performance

I've been checking out the THD (distortion) measurements of a number of speakers including all of the axioms.

http://www.soundstagemagazine.com/speakermeasurements/

It looks like the best measurements in the axiom family went to the m80 and m22 given that they had low distortion throughout the frequency range. The m2 and m3 did not do as well and most of their distortion was in the bass octaves.
Is this why people prefer the m22 to the m2 and m3? Is this distortion an audible problem?

I'll be ordering a pair of M3tis within the next month. They're single woofer and the driver is of a substantial size for a bookshelf. Those are the driving factors behind my decision, it's a tradeoff between price and performance between the M3ti and M22ti. Will the dual 5.25" sound punchier than the single 6.5"? - yes. Will the single 6.5" move more air than the single 5.25"? - yes. I've got a smallish sized listening area, I'm not looking for large SPLs (I wear earplugs at concerts all the time now to protect my hearing) just for good tonality and to set up a quality, enveloping sound stage (as they say).

Bren R.

I think that it is best to listen with your ears rather than your eyes. Then again I haven't had any coffee yet so my views may be suspect.

What is even more interesting to me is the comparision of the M2i's frequency response with the others. The Wilson Watt/Puppy 7's at 100 times the price, while of course, going lower, don't look one bit better above 70 hz. In fact, I didn't see a curve that looked better.

One wonders, looking at these curves if one could pair these with a quality pair of subs, like the HSU TN1220's, and for under two grand have a true audiophile set of speakers that would hold their own with the $20-50,000 pairs?

paulu,
See here for Alan's explanation on the THD curves.

EAR,
Since $$ does not equate directly 1:1 for quality, ANYTHING could be better than Wilson's bloated line of speakers.

Hi,

Chess has posted the link (thanks), but I've edited a few comments from my post about distortion in speakers:
". . . if you scroll down and look at the NRC curves for THD&Noise at various sound levels, you'll note that with all speakers, the curve begins to climb as the frequencies get lower and louder. On many smaller speakers, the NRC test signal is limited to 90 dB SPL, because if you try to measure the speaker at 95 dB SPL, the distortion will climb to very high levels--10% or more. We hear this as a kind of fat, bloated bass sound (some enthusiasts even grow to like it!) and an increasing "edgy" quality as distortion climbs when SPL levels get really high.

Large floorstanding speakers will generally have much lower overall measured THD levels in the bass, typically 1% or less, than bookshelf systems because they usually have larger--and more--woofers."

Remember too, that volume levels of 85 dB SPL are subjectively termed "quite loud"; and 95 dB SPL "very loud."

While lower levels of THD in speakers contribute to preferences in blind listening tests, it's really the overall smoothness (linearity) in frequency response, especially in the midrange and upper octaves--as well as the absence of coloration--that most influence our judgments of speaker sound quality and accuracy.

It's that smoothness and transparency that distinguishes the M22ti, and raises it another notch above the M2i and M3ti. Of course, the M22's extra drivers do keep THD under control better, particularly as the audio signals get louder, but neutrality and transparency are the ultimate criteria for ranking sound quality.

Regards,

Hmmmm...
I'm beginning to think this is why the same music played at a dance club sounds much harder,rather than it sounds in my room . I seem to lose that "distorded/edginess" feel when im playing music at home
. Could this may be the effect(coloration) that the topic starter of rock speaker thread seemed to be missing in the new speakers? From experience I know that adding minute amounts of distortion
to instruments makes them appear as being "louder" or actually enhancing the texture of the instrument. Its often used in drums for electronic music to make it sound a little harder/grittier.

Stbean,

Distortion purposefully added to instruments is done so in a controlled manner. That is desirable. Distortion coming from speakers cones operating at or beyond their limits in uncontrolled and undesirable.

Hi,

Double hmmm. . . Interesting about adding distortion to instrument tracks to enhance the texture of the instrument.

But re your dance club comment, I'm sure it's not the distortion but the fact that virtually all club systems must use horn-loaded systems to achieve the SPLs in bigger spaces, and it's the horn loading that makes such speakers inherently harder and edgier-sounding, particularly in the midrange and upper treble.

In lots of cases, horn-loaded systems for clubs and concert sound reinforcement have very low THD, because the driver excursion is quite small. It doesn't have to be large because the horn loading give you huge SPLs for relatively small diaphragm movement.

But the trade-off is hardness and harsh coloration, unless very precise and careful EQ is applied (and it seldom is). Ain't no free lunch, as they say.

Regards,

Chances are, the reason the sound is more raw at a dance club/rock bar is that stage cabinets are made for power handling and to be bulletproof, this is Cerwin Vega's bread and butter, you can run mains power to them and they'll hum along at 60Hz, but the tonality isn't there. Not a personal shot against C-V, but they're probably about the furthest on the fringe of this (dirty job, but someone's got to do it!)

Also take a look, some of that distortion is probably vomit, spilled beer, blown horns and discarded raver glo-sticks.

Bren R.