Axiom Home Page Forums General Discussion Advice from Axiom Owners Recommended crossover for VP100?

I was just wondering what crossover people recommended for the VP100. I currently have it set to 100HZ only because that is above the -3db 95HZ limit.

I read somewhere that the crossover point for a speaker should be 2 times the -10db output. For the VP100 that would be about 120HZ, which, as happens, is exactly the value that my Yamaha YAPO (auto optimization) suggested.

What do most of you use?

Thanks,
Jim

I don't know about the 100 but my 150 starts to drop off at 75Hz in my room. I have a global cross-over and I set it to 80Hz for movies and 60Hz for music.

Thanks for the response Mojo.

You hit upon my exact question. With the 60HZ setting for the VP100 or VP 150, I think that there is a dip introduced in the mid-bass region (60 to 85 or 95HZ). Of course how noticeable this is in just the center channel is arguable. All of my other speakers go down to at least 60HZ and will fill in with a 60HZ or 80HZ crossover point.

And it may not be noticeable at all because I bet that these crossovers are not etched into stone. An 80HZ crossover does not mean whap! the sub-woofer stops at 81HZ and the mains work for anything above 79HZ. There is probably a band of overlap.

Thanks,
Jim

I think the dip you mention is very much room-dependent. I don't encounter a significant dip in my room until 110Hz. This is a result of comb filtering due to the distance to my rear wall.

The cross-over filter slopes are usually not specified but I believe that most are either 12dB or 24dB per octave. I've been told that they are 24dB/octave on the Denons. So if I set the cross-over to 80 on my Denon, by 160Hz the response is down by 24dB. Therefore by 90Hz, the response is already down by 3dB or half-power.

The standard crossover slopes, as recommended by THX, are a 24dB/octave low pass with a 12dB/octave high pass. Most receivers, as shown for example in the Sound&Vision lab tests, follow this.

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With the 60HZ setting for the VP100 or VP 150, I think that there is a dip introduced in the mid-bass region (60 to 85 or 95HZ). Of course how noticeable this is in just the center channel is arguable

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Another related thought, how much bass material below 80Hz would be mixed for a centre channel knowing that most centre units do not handle sound in that low a range?
I think ppl worry too much about setting the surround and centre crossovers at points marginally lower than the rated frequency response cutoffs.

Good point, chesseroo. For movies, where the sound engineer is creating a sound-scape from scratch, this is probably true. They would try to cater to the THX standards. For multi-channel music, I would think that the engineers would just try to pick up every sound that they can at each microphone. I don't know how much diverting of frequencies from one channel to another would take place in post production. I may be completely wrong about this, I have never engineered a multi-channel music recording before (or any commercial recording for that matter. )

Jim