Axiom Home Page Forums General Discussion Advice from Axiom Owners M22ti with VTF-2 questions

I received M22ti + VTF-2 yesterday, and so far I am very impressed with both.
I was wandering if someone could shed some light on cross-over issues. I have an old Onkyo receiver that does not have sub-output options (no pre-amp or LFE outputs), so the sub and speakers are connected thru speaker-level-outs (which means the M22ti's are getting full range signal).
Knowing that M22ti's low-range goes to 60 Hz (+/- 3 db), I initially set the VTF-2's low-pass crossover at 60 Hz - that sounded decent, but I much prefer the sound that I am getting with cross-over set around 80 Hz - I guess this means that the 60 - 80 Hz range is getting "double production" - getting output from both the sub and speakers. Can anyone comment if this is a good idea or not? Is this, in effect, similar to turning up the the bass dial (as in bass/treble dials)? Does anyone else have any experience with a similar set-up? Thanks for any input.

It probably does blend better at 80 -- that's not at all uncommon. In fact, it's rarely truly adding more. Reflections will cancel out other reflections, while adding to others, and so on; there will be both constructive and destructive interference. The best way to do the crossover point is so that you can't tell when it switches. Try everything, and guess what, it all depends on what you like to listen to. Don't do audio to please others, but neglect yourself. You paid for your stereo so enjoy it however you'd like. That said, technically it could be bad, as generally the smaller driver that can do a frequency at the right volume will be more accurate because of its reduced mass, but do what sounds right to you. What you should do, however, is go to Radio Shack and purchase a Digital SPL meter and fix it to your listening position (a camera tripod works wonders here) and then just make the transition as smooth as you possibly can (messing with phase dial / switch is good here).
Good Luck

-Will

When I had my M22's and VTF-2, Dr. Hsu suggested 80hz as the crossover point as well.

Ultimately it should be set at what you like best.

That's a pretty sweet combo, isn't it?

I agree with DJ in the return-to-phrase "do what sounds best to you".

If you want to find a good point where your sub and M22s integrate nicely, have a friend stand by the sub, put on a piece of music then have them slowly turn up the crossover knob on the sub until it is all the way up. Then have them do the reverse, slowly turn the crossover knob all the way back down. Once you get an idea of the entire sound range of the sub as the crossover point changes from end to end, you will eventually pinpoint the crossover range that sounds best to you.
This was how i tweaked with my sub crossover until it integrated best with my M60s set to 'large' in the receiver options.
It worked quite well and is easy to do.

Based on the specs of the M22s i would not be surprised if the integrated range falls between the 70Hz and 90Hz somewhere. Once you do find that crossover knob position for your preference, you might want to mark it off with a small piece of masking tape just in case someone else fiddles with it.

Peter, as I mentioned in your previous thread, the fact that the Hsu site shows a 90Hz high pass filter on the VTF-2 high-level output, while the manual states that it's full-range, calls for clarification. If the VTF-2 is in fact rolling off the M22s below 90Hz, that would call for the internal VTF-2 crossover to be set at or near its 90Hz maximum and would explain why it sounds better set that high.

Thanks for all the input guys. JohnK, I did call HSU and verified that the info on their web site is in error - there is no high-pass at 90 Hz.
Upon further experimentation, I am finding that I'm getting pretty optimal blending at low-pass setting of about 85 Hz - it looks like M22ti starts rolling off pretty rapidly around 90 Hz.
I am continually being amazed at the audio quality that I'm getting from this combo, especially considering the price.

Good that you checked, Peter. Now what we still can't be sure about without measuring with test tones and a SPL meter is what frequencies the 30-90Hz VTF-2 control actually affects. As Tom Nousaine has shown in his sub tests, the markings on the controls are often off by 20Hz or even more, so it's possible that the 85Hz point might be actually around 70Hz. Whatever, the marking, of course, the important thing is to get the blend that sounds best. Glad to see that you're enjoying your speakers.

Thanks once again for all the helpful input guys. I currently have the crossover at around 85 Hz and that seems to give the best balance, although I notice a slight "bump" at around 60 Hz - which seems to be secondary to the room acoustics.

By the way, I am doing this all "by ear". Don't really plan on bying a SPL meter...unless someone can convince that I really ought to.

Sorry guys, I have another question. Is it ever "correct" to set the sub "out of phase" with the speakers? I assume that the phase setting (0 deg in my case) that gives louder bass is where the sub is in phase with the speakers. But sometimes I prefer the quieter setting (180 degrees) which seems to produce "tighter" bass. So should the sub always be set "in phase" with the speakers, or is it more a matter of preference?