LFE and my PC Ultra

[Thomasdk1405]

Hi !
I was wondering about the use of tuning the Ultra lower than the stock tune. According to manual you loose some output in the "upper reaches of bass" when you tune to lets say 15 hz. I now have the AS-EQ1 and tried both the 20 hz and 15 hz setting. In my graphs it looks more like I loose some from 30-20 hz region - but of course than have far more extension below 20 hz. 20 hz setting look more even from 30 hz to 20 hz and 15 hz - looses som db from 30 - 20 - but looks like they both hit the same place on the 20 hz marker.
Ok - the LFE thing - according to what I've read several places is that the LFE is defined as 20 hz - 120 hz and if recordings are like this - then why the need for below 20 hz ?
Found another forum where they list all movies and their low end bass - some all the way down to below 10 hz !!!
Now I've just read this: http://en.wikipedia.org/wiki/Low-frequency_effect
3 hz to 120 hz !! Is this then a new standard and the 20-120 is the old one ?

From the review of the old PC ultra from Sensible Sound http://www.svsound.com/Reviews/tssjan05body.pdf on page 3 the reviewer says "Going this deep is gilding the lily of another
sort, in my opinion, and it has a zero function with just
about any music and virtually all home-theater source
material." (don't know if it's ok to quote someone).
I did try the ultra with both 20 hz and 15 hz - and I think they are both good - 20 hz - I get more slam bam (like the Blue Man group dts demo - all blue in the heads) - but the 15 hz is just sooo good in Master & Commander - so there has to be information down below 20 hz ?

Both the 20hz and the 15 hz setting makes the pictures and windows vibrate + people turn their heads on the street when I fire up

Hope someone can clarify things here.

/Thomas

[mojomike]

There is without a doubt content in some movies that extends below 20hz. It seems to be present in many films of the action variety. While it isn't quite as important as the content above 20hz, when it can be reproduced at sufficient loudness, it can add to the movie viewing experience. We can debate whether this content can actually be heard or not, but it certainly can be felt. Those who consider this sub-20hz material to be useless have most likely not experienced it when reproduced properly on a good system.

In music, it is much less important, in my opinion, other than for some pipe organ material.

[Ed Mullen]

You are correct. Tuning the subwoofer deeper (to 15 Hz) sacrifices some maximum output capability in the octave above the tuning frequency (say 18-36 Hz) and not at the upper bass frequencies (50/63/80).