[terry j]

Thanks Wayne, a lot of good stuff...will know more after I read it, I dunno, another six times! ha ha.

Yes, when we first get eq and REW, there is very much a temptation to get as perfect a graph as possible. Most people though would soon get past playing with their 'new toy' and realise that sonically the perfectly flat response doesn't sound too much different from one that is a bit rough as long as the major peaks and dips are handled.

A request please, could you post a shot of the mains you are integrating the sub with, and the completed graph??

Now, this is where perhaps my own limitations on understanding may come in, as I'm confused (?) on some of your points.

If we accept that it is better to use as few eq points as possible, then I can see setting the target curve to 'bisect' the peaks and dips as a good starting point (the line of best fit as it where), but would not the best way to go is set the sub output level to bisect the target curve rather than leave the level and offset the target curve?? The way I see it, and do it (so if I've got it wrong I'm very interested!) is that at the end of the day (for this argument let's ignore a house curve) we want the sub to blend in with the mains seamlessly. So, if our mains output is set at 75 db then of course that is the level we want the sub to be at.

If we take as an example a case where (using your method) we offset the target curve by five db -for exageration - so we get the peaks and dips bisected, then are we not then running the subs five db hot??

Out of curiousity, when you set your house curve, do you take into account the relative listening level?? ie the Fletcher-Munson curves. Setting say 20 hz the same level as 80 hz at 60 db would be different than at 90 db???

I can perfectly understand your example with the bass guitar and being able to 'notch' out rather exactly a note in the scale. But that is not how it works in our normal situation is it?? What I mean by that is that IF my room had a peak that exactly fell on one of those notes, and boosted it by 5 db say, then that is equally bad as your example where we have notched it out. However, by applying the correct filter then have we not brought the relative level of that note back down correctly??

The very interesting question you raise is whether or not changing the LHS scale may or may not be more in tune with how we actually hear and perceive music, that is certainly worth some further thought, experimentation and feedback.

I also understand what you mean regarding smoothing on the bass, I too have at times gotten perfectly reasonable and acceptable results even when smoothing (say 1/6 oct) has been applied. At times it could very well be worthwhile to switch off smoothing to make sure we have exactly the correct frequency to eq, and then switch back to a smoothed graph for the filter size.

Once again, not only an informative post Wayne, but as usual an enjoyable one.

EDIT

Your post contained so much I keep thinking of other questions!

Regarding the 'lessening' of mid bass with your method-attributed to the 'excess' energy in the standard sub rolloff vs the sharp knee-, would we not see any excess energy in the resultant FR we run full range??

If there is in actual fact less energy in some part of the spectrum, we would see that difference in the FR, yet if we have a 'flat' response, via either method, then we have a flat response no? So either there was a 'hump' in the old method, or a 'dip' in the new method, or am I missing something completely?