I was doing a little tweaking the other day on my VLAs and really learned to appreciate even more that little Dayton HPSA 1000-R Bass Amp. I had been using that single parametric band of EQ to flatten out the lowest frequencies coming out of those towers, since their design has them starting to roll off a bit before 20Hz. But, I recently found a better use for it.
Early on I had graphed my room response 1Hz at a time in the bass region when I had first set-up and positioned the bass towers for their best performance. I then used the features of that bass amp to dial things in even more and made a new graph. I recently took another look at this new graph and realized that I had missed something.
My room only has one peak of concern and that is around 4-5 db @ 37Hz. Just above that is a deeper dip at around 48Hz. Then, just above that is the point at which my bass towers begin to roll in. As I looked at this it suddenly became clear what I could do here and I could not believe that I had been missing it all this time.
I set both amp controls back to zero, except the gains and set-up my disk of test tones. First I increased the gains by about 5-6 db to bring the tone @ 20 Hz up to the flat reading. I did this by comparing it to other readings of frequencies I already know to be flat. Then, I used that single band of parametric EQ to notch out the peak @ 37Hz, which had now increased another 5-6 db with the increase in gain. My hope was that this boost in gain would also help fill that dip @ 48Hz.
The end result after dialing everything back in is now a flat response from <20 – 42Hz and to the rest of the higher frequency spectrum. Unfortunately though the dip centered @ 48Hz remained unchanged. I remember reading on this forum that enormous amounts of power are often required to fill in such dips, and so I now see this is true. It is a good thing that my ears are less sensitive to that dip than they were to that peak at 37Hz.
