hi everybody
I am quite new to this game, but I must say with the excellent help available on this forum I'm very happy and just a little suprised with my progress. It really is an excellent program.
I have posted before regarding poor soundcard response using the onboard soundcard. As poor as they were, it nonetheless was quite adequate for low frequency use.
Since then, I have been able to borrow a friends external soundcard, which has enabled a larger frequency range to be looked at. The graph drops off heavily when measuring full range responses, this I attribute to the radio shack meter not really being of much use above 10k ( is that true?).
Anyway, after having 'mastered' the program sufficiently to feel the purchase of a BFD would be justified, I also managed to 'score' a subwoofer with which to play with. Things are just a little bit tight right now, so I often gazed longingly at the DEQ 2496 sitting next to me, and knowing that it has parametric functions wished I could use it instead. But of course, it was unsuitable as the Q etc was totally incompatible with the REW program.
Browsing (again) thru the various posts on the forum I came across one where someone wanted to use a Rane (?) with REW, which was supposedly no prob. One of the resident wise ones ( Brucek in this case) mentioned that it might need to have the choice of unit in the equalizer tab changed. Intrigued, I had a look and blow me down, selecting FBQ 2496 made the units in the parametric table compatible with the DEQ 2496!! Admittedly using that equalizer choice puts a BW OCT unit as .25 for example, but it doesn't take a rocket engineer to work out that that is equivalent to 1/4 in the DEQ.
So off I went.
raw sub response cutoff 50 hz.jpg
this shows my raw sub response. After using the recommend filter options ( and they are very accurate predictions by the way ) I ended up with this
pretty close just using parametric on sub..jpg
this only used three or four para's, so for the sake of illustration I artificially lowered the target curve in order to 'need' more para's.
for the sake of illustration, artificially lowered target.jpg
Then off I went using the recommend settings and ended up using nine para's of cut boost, and manually added one with positive boost to end up with
10 filters used, one manual boost 40.83,5.5,0.167.jpg
I did this deliberately because the DEQ has only go ten bands of parametric, and I wanted to explore it's limits, and it seems as if we've maxed out the unit.
However, the DEQ has also got a 1/3 octave GEQ so I incorporated that into the equation. Back to the raw response
raw sub response cutoff 50 hz.jpg
i then used the GEQ to pre filter the response before using any of my ten PEQ's.
graphic only no para yet. 20,-5.5;25,-10.5;50,-11;63,-12..jpg
In this graph I've used the GEQ to dial in -5.5@20,-10@25,-11@50 and-12@63.
Then using the recommended paras I got this
sorry, I must have loaded the picture incorrectly because it's not in the graph format like the others, so I can't show you. Bugger. Rest assured it was as close to the target response as before, but the point I'm making is that by using the GEQ prior to any paras, I only needed one parametric filter this time instead of the previous nine.
I've had a few beers now so it's a safe bet that any more illustrations for tonight are 'not on'!
so that's all for now.
I thought this might be of interest because the DEQ is often used higher in the chain ( ie perceived to be of higher sound quality ) than the BFD's and we still have the auto eq functions to play with for the response well above 200 hz. (eg, I've still got nine more paras to play with to help sort out speaker response anomolies in the entire bandwidth).
Tomorrow I will get on to incorporating the auto eq with the sub eq, and see how it goes.
here is the raw full range response
raw full range response.jpg
and here is the response after fixing the sub
full range response after g and p equalizers added..jpg
What is of interest here is that perhaps (?) the use of this unit can go a long way towards fulfilling the wish list Sonnie has got going for a tailor made bfd?
For example it does it's own RTA with the Behringer mic, but unfortunately I can't get it to replace the radio shack mic yet. Hoping that it is my lack of knowledge and expertise, but unfortunately I'm beginning to think that I can't actually get the mic measurement to the analog out and hence into the computer. Bummer. If we could then that would be a major pluspoint.
Hope this is of interest, at the very least I can muck about with it for a while more and maybe not need a BFD. By the way, the number of times I checked on the Behringer website for a BFD 2496 !! ha ha.
lots of love
terry