My experience adding subwoofers to 2 channel

I have used a tri-amped electronically crossed three way line array system that I built myself.  This worked seamlessly.  The 12 inch woofers worked well as subs essentially running 32- 250 hz.

I am currently building a new system to go downstairs(sine my wife commandeered the other one for watching movies upstairs).

This one will be a Quad amped electronically crossed  line array: per side:  15 ribbon tweeters, 25- 2 inch midranges, one 8 inch mid woofer, and one 12 inch sub woofer.  

Electronic crossovers(digital or analog) are the key to making this work, IMO.

I recently purchased some transmission line (like) ported towers and was unable to successfully integrate my single sub- so I sold it.  
I have had no problems in the past with typical ported monitor speakers- and am quite good at integration using RTA, phase control for time delay, etc.  
I could not get the bass to sound good- often hard sounding despite my efforts.

I had no peaks in the response either so EQ will not help.  

I'm guessing that transmission line ports are somehow more difficult to integrate.
I miss the impact my sub provided and any advise would be appreciated.  

zarathu,
     
    I wasn't implying speaker and sub line array configurations don't work well, I know they do.  I was just stating these arrays are best for a dedicated room or stage, using them in a living room requires serious rearrangement of the décor.

Tim    

The idea mijostyn has (and others, he is far from alone in this) of bass timing being smeared is of course based on the false assumption that human hearing responds to all frequencies equally.

That this is false is proven by a simple experiment in which subjects wearing headphones are played test tones of short duration. This test demonstrates conclusively that less than one full wavelength of low frequency bass is not heard AT ALL. Say again, human hearing does not even register very low bass less than one full wave duration.

Understand what this means? A single 20 Hz wave lasts 0.05 seconds. Anything 20 Hz lasting less than 0.05 seconds will not be heard at all. Sound travels roughly one foot per millisecond. Ballpark. So think about it. Bass can travel FIFTY FEET before we are even capable of hearing it.

So I ask, from the point of view of timing- not frequency response, just timing- how in the world is it possibly going to matter where you put the subs? Any normal size room the bass is going to leave the speaker, bounce off half a dozen surfaces, probably more than once, all before you even hear it.

Yes timing is super important - at high frequencies. I take heat on here all the time for saying speaker placement being off as little as 1/8" matters. But that’s high frequencies. Low bass is completely different.

Just one of several deeply ingrained yet totally false concepts hampering our ability to understand the beauty of the distributed bass array.

avanti1960,

     You may want to try the 'room crawl method'.  Place your sub at your listening position, play some music with good and repetitive bass and walk around the perimeter of your room counter-clockwise starting at the front right corner.  Walk slowly listening for an exact spot where the bass sounds best to you (accurate, detailed and natural).  When you find this spot in your room, just move the sub to that position and verify the bass sounds good from your listening seat. You can use your RTA at this point for fine tuning if you'd like.
      If you prefer good bass response throughout your entire room, and not just at your listening seat, the only solution I'm aware of is a 4-sub DBA system.

Tim