Axiom Home Page Forums General Discussion Technical Questions M60 crossover frequencies

I cannot seem to find the crossover fequencies from W-M-T for the M60Ti's. Anybody out there have this info?

Bob, the info on that point has varied a bit. Quite some time ago Alan reported that the crossovers for both the M60s and M80s were at 200Hz and 3,400Hz. In an even earlier post a 2,500Hz crossover was mentioned. Possibly Alan or someone can update this information.

According to the M60ti manual, they are 200Hz & 2Khz. The M80ti is 160Hz & 2.3Khz.

Odd- one would think having an extra tweeter and lowrange woofer would mean stress would be taken off the dual mids. Interesting!

Hi all,

Joema has it right. I just verified those figures on our latest chart from R&D.

Regards,

aww man. we need to get some of this stuff on the website!.. unless of course its confidential!

Alan et all,
So effectively what you're saying then is that when we configure the ceceiver for "SMALL" mains with a crossover frequency of 80 Hz to the sub, that leaves the 2 - 6 1/2" "woofers" to only receive a 120 Hz bandpass between 80 and 200 Hz? Seems like a waste of 2 speakers, well, at least 1 of them.

Bob

Hi,

Everybody thinks this way about crossovers--that the response from the M60s' woofers suddenly stops dead at 80 Hz and that by setting the front mains to Small and using a subwoofer you are somehow "wasting" the output of the M60's woofers.

It doesn't work that way. Every crossover has a slope, so the transition becomes gradual. The slope is expressed in dB per octave, thus an 80-Hz crossover with a 12-dB per octave slope would mean that the M60's woofers would be 12 dB down (-12 dB) at 40 Hz. That means that the woofers are still producing bass at 40 Hz, but at about half as much output as at 80 Hz. At 30 Hz, the output would be diminished some more, but you get the idea. . .the woofers just don't work as hard as normal (hence distortion is lower) and gradually turn over the really deep bass duties to the sub as the audio frequencies get deeper.

Crossover slopes are designed with either 6 dB, 12 dB, 18 dB, or 24 dB-per-octave slopes. We don't publish this information on the web site because neither Ian nor I nor Peter (our R&D director) want to get into protracted discussions over crossover design and slopes. What matters is the sound quality from the speakers--its accuracy, transparency and freedom from coloration and distortion, as well as its anechoically measured smoothness, especially throughout the midrange and upper octaves.

Regards,

I hate to be presumptuous, but maybe a visual will help here... (it's a HIGH frequency rolloff, but if you hold a mirror to the screen and flip it horizontally, you get the picture)

Bren R.

BrenR,

Sorry for the confusion. I was talking about the high-pass filter you activate when you set the front mains to "Small" on the bass-management menu of an A/V receiver. The high-pass filter in the receiver passes the highs, mids, and bass above 80 Hz to the front mains and center (I'm simplifying for clarity, I hope), then gradually rolls the bass off to the mains (at a pre-determined slope), redirecting low bass below 80 Hz to the subwoofer.

I agree that in the M60s, it's a low-pass filter to the woofers, a high-pass to the midrange (above 200 Hz), and then another high-pass to the tweeter for frequencies at 2 kHz and higher.

Regards,

Alan,

Was just trying to illustrate what a rolloff characteristic looked like (@ 6 dB/12dB per octave) and that it wasn't a hard cutoff. Couldn't find an exact representation of what you were talking about, so I think I've muddied the waters again. My apologies.

Bren R.

BrenR,

The illustration is excellent. I think anyone can understand "slope" by looking at the diagram. Speaking of which, years ago while skiing at Mont Tremblant I once took a wrong turn and ended up on an expert run that looked like "C". Took me an hour to make it to the bottom. "A" is more my speed. . .

Regards,

no bandpass on the midrange driver? just highpass?

In reply to:

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no bandpass on the midrange driver? just highpass?

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Uhhh.. A band pass filter is a combination of a low pass and a high pass filter. As Alan stated, there is a low pass sending everything below 200Hz to the woofers, and 2 high(er) pass filters for the midrange driver and tweeter. In essence, that means that there are 2 bandpass filters in the M60s. One made up by the low pass filter and the 1st highpass filter, and one made up by the 1st and 2nd highpass filters. I'm lousy at ASCII art, but see if this can help you visualize it:

Low pass filter --- High pass #1 --- High pass #2
................ BP #1 .....|........ BP #2 .............

I think what he was asking exactly was, do the midrange drivers get everything above 200 Hz, including everything above 2kHz (which would be a high pass filter to the midrange.) Or do they only get everything between 200 Hz and 2k Hz (which would be a bandpass filter.) The way Alan worded it would suggest that the midrange and tweeters were both getting the signal at over 2k Hz, with the midrange also getting everything from 200 to 2k. I took it to mean a bandpass to the midrange, but I can see how it would be unclear.

Good point. There was some leeway in there for interpretation. I did make an assumption that the 2 high pass filters were setup as a bandpass filter for the midrange driver.

Kicking this one back to Alan...