You might want to try different locations for the sub, like maybe a corner. That usually gets better readings, both smoother and better-extended, than center-of-wall placement. It also may reduce the span between the highest and lowest peaks, which will make for easier equalizing. Once you find the best location, you can add your second sub there, if it’s a match for the first.
Regards,
Wayne
The HT, equipment closet, and entrance area is partially underground with concrete on all sides including the ceiling but the ceiling has an additional support of very thick steel that is supported by the large steel beams. It was a reverberation chamber before any framing was done with the exception of an opening where one of the future doors went.
I tested with my DIY subwoofer before the room was completed at the center front wall and ended up placing it there since the bass seemed to be most even throughout the room with it being there. I also added a hookup wall plate in the right corner of the room for future use because while I was listening it was not very loud there and I thought it may be a good place for a subwoofer someday.
I bought the new subwoofer and a new driver for my DIY speaker box that I tried but it did not work having a subwoofer in my back right corner and the new one in the center. They were canceling each-other out and my new replacement driver (4 ohm) was becoming very badly distorted by my Marantz 180W @ 4ohm mono amplifier so I returned the speaker to the store.
I have moved the sub and tried different locations by ear so far. The first place I had it was the back right corner. My father complained that he could localize it from the back right seat that he usually sits in. I tried a 50Hz and 80Hz crossover and neither was working to eliminate that problem. I had placed it there by placing the sub at the center front row seat and finding where it sounded the best. I could also localize it on the right side also in the front of the room after using the receivers automatic setup during certain scenes because I had to turn up my subwoofer very loud to blend with the mains. That was before bass traps however.
I ended up moving the subwoofer to the center of the back wall where according to my folks, they were unable to localize the sound anymore and it did not sound "boomy" to them there. I left it there sitting on of my equipment rack because I was unable to place it behind or bellow it. That is where I tested my first time with REW and began placing room treatments. The measurement looks very similar to what I see now with it placed in the front of the room but I will have to try placing it there on the riser (which I am not sure will work) after I move the equipment to retest that location more accurately.
I tried the right side of the room and also the left side like shown bellow after installing bass traps - the new 244 traps and prior to doing any new testing with REW more recently. It sounded excellent on the right side of the room but I was still able to localize it. I could not place it on the floor which I think had to do with the problem. I tried facing it different directions but it seemed to make things worse. The left side sounded very quiet in comparison to the right.
The closer I put it to a wall, the more I am able to localize bass there with the exception of placing it between my left tower and center channel as seen bellow. It sounded good there but I was able to localize higher frequency sounds there around the crossover. It would probably be the 80Hz peak that I am seeing during my testing.
I would mostly like a second subwoofer to extend the low frequency which I understand is possible. I think that I would place it in the back of the room if I could and set the phase on the subwoofers accordingly. I have the phase set to normal in the front of the room now and in the back of the room, reverse was working best. I found that in the back it liked to be slightly closer to the left wall, which has rooms on the other side and is not drywall/insulation/bedrock such as the right side of the room. It might look something like bellow except that I would try tweaking them left and right slightly which I am able to do with good results. The speakers in the SketchUp model are not to scale but the rest of the room is. I have planned to first try placing the dipoles on the right and left sides of the front row and move the rear channels away from the center of the back wall and more in a Dolby type configuration. I'm not sure about the bookshelves yet. I have since moved my panels on the front wall together, and placed standard sized GIK 244 bass traps on the front stage area covering the front wall and in front of the screen, which I need to complete placing more under the screen area.
There is conduit behind my screen for running wiring but I have not yet decided if I will use that or hide it behind baseboard on the stage.
It looks like this currently.
Moving it forward and back did not make any difference but if moving it to the left or right between the stage a few inches helps, I'm not sure yet. It seemed to help in the back of the room but it could have easily have been my imagination. I will test that with REW and see what happens.
JohnM,
Thank you that explanation helps allot and I think it is beginning to making better since to me now. The higher filter I tried applying was trying to lower the peak around 250 because according to the RT60 on my measurements with the sub, it went off the chart for one of my seats, and the other seat was slightly above .08 seconds at that frequency to about 300Hz. It did a similar thing for my sub higher above that also in the testing. I had the subwoofer speaker target in my settings with the crossover at 80Hz and I had thought the sound would not be going so high with these settings enabled unless there was some kind of adjustment I was supposed to be tweaking. It is my mistake, and I think this is only a result of sound after the speaker has began loosing signal. If that is not what I am seeing, please let me know. :sad2: