What process did you use to integrate multiple subwoofers for 2 channel listening?

For everyone saying 

“to do this right you need X” 

He has a mic and software with subs that have a low pass control. That’s all you need. Nothing else fancy especially a dsp with converts analog to digital to analog again. 
How much did you spend on your DAC and you’re trusting the DAC inside the DSP to reinterpret it all?  
All those extra things are for people that want the easy fix without actually gaining knowledge on how your system works together.

Again doesn’t need anything new (I understand people love to throw money at a problem but it could be fixed with what he has before the shipment arrives); just spend a little time with the low pass filter while looking at you readings from the mic.

Minus 5 db is not a null. It's a small dip. A null is an infinite dip. Your problems seems to be more in the high bass/low mid. If you can trust your measurements.....

Thanks to all for your useful posts. I appreciate them.

@golfnutz Good point — it seems like you’re suggesting start with one — using Enrico — then go to two, then three. I have the tools needed to do what you suggest. Comparing to the naked speakers is a good idea. This is what I’ve done in the past. (I have been doing REW sweeps since July of last year, including with moving the sub. At one point, I had the sub 4 feet off the ground to check for vertical effects.) I like your SPL graph. As for shaking the house, isn’t that our duty as manly-men-with-subs? ;-)

@mijostyn  I do really want to do this right. Because I just bought all my tube gear and powered subs, I will probably wait before buying a digital preamp with digital bass management capability and then selling off my active subs for passive subs. I see that if you’re right about this, I’m going about it the wrong way. But for right now, I’m looking for solutions to what I currently have. Down the road, perhaps I’ll change everything out for something you’re describing.

@mapman Mini DSP would be a decent experiment. I just have to absorb the idea of adding it to the signal path. It’s a question of which is worse — adding another thing or some bad curve sections.

@powemi I have a DAC I really like (MHDT Orchid) with a good tube and really nice upgrades by Grannyring. I really incline, as you say, toward trying to learn my room and my system. I want things to fit together organically, and I honestly enjoy moving a panel or twisting a knob and noting the change. I get in a headzone of iterative trials — I can go for hours, and all the while, I’m learning how physical space, quantification, and acoustic experience align. I would worry that a DSP would shortcut me out of this process. Still, I’m losing hair and if I pull too much more out…well…

@tvad Thanks tvad. I don’t know why Duke would want to advise me when I’m not buying anything. He’s got to be busy enough.

Hello,
I am not going to say I am an expert in any way. Some of this can get expensive because subwoofers are not cheap. I have found that trying to control sound at the lower levels can be the toughest thing to control. I have also found out over the years there are equipment audiophiles (likes to tinker with equipment to change the sound), music audiophiles (only wants to listen to good music), and a combo of both. I am both. Take on one sub at a time with the sub crawl. Best of all it’s free except for your time. Read up on the papers and forums to try their ideas. Again it should be free. Finally buy a Mini DSP or crossover to help you remove the humps or nodes. Just remember our biggest issue is the room. You might want to invest in some bass traps and / or diffusers. The node or hump you are talking about is not the frequency that bass traps fix. They are usually above that. I’m speaking in general. This can be frustrating especially if you are not an equipment audiophile. Finally you can hire a guy if you have the means. Usually it’s $100 per hour in the Chicagoland area. MC may not have patience but he did tell you what to do which you gave someone else credit for the DBA. Basically the more subs you have the less volume they play so those waves don’t have to travel as far which reduces humps and nodes. Try the first one next to you listening position pointing forward toward the front speakers. Then one in opposite corners of the room back to front. Think about it like dropping a stone in a pond at one end. The waves remain big and travel all the way across the pond and back again.  Now two people drop stones at opposite ends. The waves get smaller when the meet. As you drop more stones the waves get smaller or canceled out. I hope this helped simplify the understanding of controlling bass.