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Sonic Differences at Various XO Points

Zing

Retired Admin
Superstar
This afternoon, just for shits & giggles, I thought I'd experiment a little to see if I could hear any difference between crossover points of 200Hz and 60Hz. I took a few quality recordings, selected an appropriate track and played about 30 seconds of it with a 200Hz XO and then again at 60Hz. One more time at 200Hz and one more time at 60Hz. I could not discern any difference. I grabbed another CD and used another track and repeated the same process. Again, I could not tell the slightest difference in any aspect of what I heard.

Is this normal and to be expected?

I, for one, fully expected an obvious difference. Either in the way of 60Hz being way too low or 200Hz being way too high. But I found it shocking that about an octave and a half change yielded no sonic difference at all. I've been using a crossover setting of 90Hz since the new subs arrived but as a result of this experiment, I decided to increase it to 100Hz. Why? If I can't hear a difference, I may as well let the woofers of my mains concentrate on their midrange duties and let the subs sweat through their bass duties.
 
Try using a sweep test tone (20Hz/20kHz) and note the smoothness/seamless transition from speakers to subwoofer. The sound pressure level should remain constant, or close to constant throughout the sweep. If there's a noteable drop in level that could indicate the X/O is set too low, meaning the speakers low frequency drivers peter-out before the subwoofer(s) pickup the task of reproducing low frequency signal.

[youtube]http://www.youtube.com/watch?v=mX27e9SrlfA[/youtube]
Rope
 
According to what I've read, 200Hz is around the top of what is considered the bass range of frequencies. Sounds to me like you have a really great match between your subs and the mids/woofers in your left & right speakers. :handgestures-thumbup:
 
I use an ICBM-1 Xover to do bass management between the mains and the three subs dedicated to them / the task. One of the beauties of this arrangement is that I can instantaneously change Xover frequencies. They're normally set at 40 Hz, but I can swing through 60, 80, 100, and 120 before hitting "bypass." While I can perhaps notice a very very slight difference on the way up, it's really only between 120 and bypass that I'm pretty sure I can. But it's a very small difference.

In my case it's because the Koss stacks are pretty darn capable of generating a lot of clean bass all on their own (-3 dB @ 29 Hz), so offloading some or most of it to the subs doesn't make much difference sonically on almost any program material - even with full bypass. It's also because the three subs generate such a large even bass footprint on their own (as the Koss stacks do on theirs) that there's not much difference.

Basically running at 40 Hz with the stacks and three subs provides for even deep bass throughout the (relatively small) room, while ensuring that the Koss and their associated amps just loaf along no matter what gets thrown at them.

(And all the LFE gets sent to a separate dedicated sub. The above just refers to bass management.)
 
If you are driving your fronts with a power amp (which I think that you are), set the x-over and listen with the following configurations:

1. Front/Left Speakers and Subs On
2. Turn off Power amp to Front/Left Speakers and leave Subs On
3. Turn on Power amp to Front/Left Speakers and Turn Subs Off

Do this at your Different x-over settings.

This will give you an idea of what they are doing independently and help you make a decision on what is best.
 
No. After multiple attempts, I was starting to think my Mobile Pre may be the culprit. However I started dabbling with REW and the Mobile Pre works fine.
 
I can tell you this, in the car Audio world, that is a drastic noticeable difference just as is changing the slope.
 
I am not very clear on your setup? Do you have two subs and are they in close to the L and R speakers?

Do you have more than two subs? and where are they placed.

If you have one sub over in the corner of the room you should notice that you are able to locate the source of the bass and walk to it if blindfolded. If the crossover is below 100 hz you will find it harder to locate the sub as your crossover goes lower.
 
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