Home theater crossover question


I mounted my surround side speakers on the wall, so I used my Onkyo TX-SR803 receiver's auto configuration feature. I went into speaker setup when it was done and looked at the crossover settings, and now I have a question.

It set the front speakers to 200hz and the subwoofer to 120hz. Assuming the front speakers send everything under 200hz to the sub and the sub only goes up to 120hz, does everything from 121hz to 199hz get lost? Shouldn't the speaker crossover point be the same as the sub? Thanks.
scuby
I'm having an epiphany at the moment, as I don't think I'm properly processing your quandary. I think you are correct, if your sub doesn't have a bypass, then you're limited to crossing over at or bellow that 120 hz setting. But I could be missing a brain cell on this one. Doh! It must be late.
Anyway, email your sub manufacture.
Let us know.
Kal says "all's well" and Kal knows what he is talking about, but I disagree with him anyway. If your subwoofer puts out anything much higher than 80 Hz, then it will be localizable. In other words, you will be able to hear it thumping away in the corner of your room, or against the wall, or wherever. Sound loses its omnidirectionality above 80 Hz. So you should manually override the crossover settings and set both the subwoofer and the front mains to 80 Hz, for upper and lower crossover points respectively. If your front mains are so small that they can't get down to 80 Hz with ease, then you must have two identical subwoofers, placed beside or under each front main speaker, and then you can make the crossover as high as you like.
Javachip is certainly correct about the localizability of the sub when it is asked to perform much above 80Hz but that was not the problem asked about.

In fact, I see more problems in lowering the crossover from 200Hz to 80Hz, more than an octave, if the main speakers really are incapable of low frequency output. Doing so will force them to reproduce, with requisite power, an octave or more below their abilities. Since we do not know what they are, we cannot be certain but I would proceed with caution.

IMHO, better a localizable sub than blown speakers. The solutions include repositioning of the sub close to the main speakers and/or replacement of the main speakers with more competent ones.

Kal
Like Kal said, the slope of the crossover is also important. That will take care of the 120 to 200 Hz range.

However. also like Javachip says, if your sub is crossed over that high, you're going to localize it. Even more problematic in my view is the fact that your crossover is is the audible mid-range for human voices, to which the ear is most sensitive.

You may not want to hear this, and you didn't ask in your thread, but I think you should seriously consider new front speakers if they have to be crossed over that high. There are many respectable, inexpensive, smaller speakers that don't have to be crossed over that high. There are too many problems that your settings will cause that will noticeably detract from the enjoyment of your HT.
Thanks for all the responses. My speakers are Infinity TSS-1100s (5 small 2-way speakers and the sub). Infinity recommends a subwoofer crossover setting of 120hz-150hz for the setup, so I reset all speakers to crossover at 120hz. Javachip and Kr4, the small speakers are rated at 125 watts and the self-powered sub at 250 watts, so I guess they can handle lower crossover settings. I may experiment with 80hz and see if it improves midrange response for CDs (2-channel system is off to listening room).

I think my original question has been answered; at 200hz for the front speakers and based on the sub's frequency response, I would lose part of the audio spectrum.