[Otto]

Hi Carel, and welcome to the Shack!

carel1966 wrote:

1) Will it make sense to purchase 2 microphones to get readings from my ‘no 1’ and ‘no 2’ seating positions at the same time? This will allow me to correct to an average that should be acceptable across both positions. (It will also allow me to measure with 2 microphones more or less the same distance from each other as our ears in the ‘no 1’ listening position.)

Well, REW doesn't allow us to measure two inputs at the same time, although something like that could be possible for a future release (technically possible, I don't think it's really under consideration at this time). So you wouldn't be able to measure two things at exactly the same time, but you could measure them one right after the other, and having two mics set up would save you some time in relocating them around the room. It would also save you any concern that the mic might not be in precisely the same location. There are a few people around that have averaged their response for various measurement points throughout the room, and I think it's a totally valid idea.

2) I am currently getting an -5.5db to +5.9dB response in the 20-80Hz range. In order to achieve this I had to boost 2 frequencies by +6dB using a high Q (0.1C). (I know this is not recommended but with the equipment I got currently is the only way to get to within an acceptable response graph.) My question is if further correction will bring any real sonic benefits?

A few things.

You can plot multiple measurements (up to nine) on the same set of axes by using the "All Measured" tab in the graph area of REW. It makes it a lot easier to see what happened, but it's OK for this one. I don't necessarily see where you would have boosted with two 6 dB filters -- maybe around 70 -85 Hz?

Do you have your mains on? It looks like you're still getting response out to 200 Hz... If the mains are on, remeasure with sub only. It's quickest and easiest to do it on its own since that's the thing we're really going after. Of course, if you wish to use your preamps EQ for sub and mains, it's a bit of a different animal that applying the BFD directly to the sub, so it's up to you.

What's your crossover point between mains and sub?

What sub are you using.

Have you played with room placement? I'm thinking that that giant hump at 25 Hz must be coming from the room. I know how it is if you can't move the sub around the room, but you might be able to get some better responses right off the bat if you can change placement (sometimes even a little).

Do you have any idea for how much headroom your sub may have? Is it turned up half way at this point? More? Less? Do you use it to its limits?

To answer your question -- yes, I think you can get better results with a BFD. Your response is a little rocky, but you should be able to clean most of it up. There are still a lot of things to play with!