R-DES The System in Action
Ok, enough with the theory - let's see this thing in action. When I got the Onix R-DES, it was at a bad time. My in-laws were in town and we were preparing for my son's third birthday party. So I hooked it up and set it to "Bypass" so that it would be ready to test once the commotion settled down. The absolutely first thing I noticed was a significant increase in the amount of bass. I checked a rechecked the box to ensure that it was set to bypass (it was). When I finally got time to measure it, it seemed that the R-DES on bypass still increased the bass about six decibels.
Once everyone left, the first thing I did was take some measurements at different locations within my room. Because of a challenging layout (who doesn't have this?) there are limited locations to place the sub. I was also unwilling to re-wire the whole setup just to check locations that I knew either I wouldn't like or my wife would veto. This limited me to one wall from about the midpoint to the front corner. I didn't place the sub all the way in the corner as I've already done that and I know I don't like it there:
Original Location Near the corner
Moved Forward Facing Forward
The first three placements had the sub facing the center of the room. The fourth had the sub facing the back of the room. The original location was just less than half way down the side wall facing into the room. The third had it facing inward but moved much closer to the center of the room. The last had it facing the back of the room so that the woofer was at the midpoint of the side wall. The corner placement was obviously the worst as the reinforcement made all the problems worse. For those of you out there that think speaker placement doesn't make that much of a difference, I beg to differ. The differences in the measured curves were substantial and some of the placements were mere inches apart. Regardless of placement, I have a 60Hz and, to a lesser extent, an 80Hz null and a bump at 30Hz. As there is nothing I can do for the nulls with the EQ, I can do something about the bumps. I chose the Facing Forward location and quickly got to work.
I took measurements, adjusted the EQ, took more measurements, adjusted the EQ some more. Over and over until I was about sure the next iteration would have it perfect. I even dutifully kept track of all the different curves, saving and labeling them for inclusion into the review. And then Mrs. Andry walked through the room and said, "Oh, you 'e not going to leave the sub there are you?" For those of you with a significant other that has a say in your listening room, don't get so caught up in the quest for perfect placement that you forget to solicit opinions. So, I took a break for dinner before we started haggling about the placement of the sub. As the forward-facing orientation seemed to be working the best, I stuck with that but was asked to move it farther toward the front of the room. I countered by suggesting that we move it away from the wall a bit. Surprisingly, she acquiesced. I took some new measurements. This is what I got:
Not as good as my previous placement but not so bad either considering how bad it could be. Pulling it away from the wall helped. There was a huge bump between 20 and 40Hz, the expected null at 60Hz, and a bit of a bump at 70 and 90Hz. The first thing I figured out was that experience using the EQ makes a huge difference in your success. After only a few tries I ended up with this:
Now that is what I call an improvement! Now, am I done? No, not in the least. I'm sure I can get that line a little straighter and I'm going to keep tweaking until I do. But I had to start the review sometime, so this is where I was when I completed the review. Also, it is obvious that I need to build some sort of 60Hz bass trap. That has suddenly become 1st on my "to do" list. That, too, is the power of this process - once you know where your problem areas are, you can devise a plan of attack. It is one thing to recognize you have room issues; it is another to have a plan of attack against them. Now I have a plan.
Remember, these results are only valid at the one position that I took the measurements. I'm fortunate enough to have had the foresight to purchase theater seating with a double seat in the center. This allows the wife and I to sit close or for me to sit in the center when conducting reviews. I EQed my sub from the center of this double seat. If I wanted to get as smooth response as possible for all the seats in my theater, I'd have to take measurements at each seat and try to create a curve that gave the best response over all seats. Very likely that "sweet spot" wouldn't be as good and frankly, since it is mostly me and the wife, I don't have any interest in going through all that hassle at this time.
