My experience adding subwoofers to 2 channel

I use a pair of Audiokinesis Dream Maker speakers, plus a pair of their LCS "effect" speakers firing towards the ceiling. I just want to point out that the LCS helps with the bass too, although their main purpose is to enrich the total sound (a variant is called "Space generator"). Each LCS has two 8 inch woofers and a tweeter. Combined with the two 10 inch woofers in each main speaker there is quite a lot of "woofer power" which fills my 20 x 27 feet room nicely. Although the bass would probably be even better with a Swarm or Debra system, I can do some of the same thing - position the LCS for best bass, ’decorrelate’ the sound, etc. I had a Velodyne DD18 sub that went deeper, but also introduced tension in the sound (and two REL subs before that). All in all I prefer the system I have now. In my system it is important to fine-tune the volume of the effect speakers relative to the front speakers "just so" - and further down than I thought at first. They should almost not be heard, "disappearing" behind the front speakers, yet adding to the total sound experience.

Noble100 - re: debra / swarm system - phase changes. I have found reasons to not always follow Audiokinesis advice "mechanically" - it depends on your room and a bit on your listening tastes also. So I’ve now found that my main Dream Maker speakers - to my ears, in my room - sound better crossed a bit behind me, not in front of me like Audiokinesis advices. In other words, a more conventional speaker setup with less toe-in. This may apply to my use of the LCS effect speakers also. Not sure yet. Based on Audiokinesis philosophy the idea is to spread the reverberant sound around and "decorrelate" it as much as possible. Based on advice from James Romeyn at Audiokinesis, I run the effect speakers so that one channel phase (polarity) is shifted. And some other mods that I am not sure about. The great thing with the Swarm and Debra system - and the Dream Maker / LCS system I have - is that it is very much up to the user. Position the speakers right, in the room, adjust phase / polarity, and the reward will be there.

Dear all, as stated in a post above, I’ve tried a lot of subs, and gradually gave up on it, preferring another system (main + effect speakers) instead. Why? I worked a lot with sub positioning. Getting the subs and the room to agree. The more that can be done in the analog domain the better. Next, I worked a lot with equalizing and adjusting crossover, especially with the Velodyne DD18, recording in REW, looking at the output, and so on. Eventually, I got bored. +1 to mijostyn, above - "bass is about feeling".

Why did I get bored? Because, with a very good set of tube amps driving big horn speakers, the sub importance declined. I decided that I was willing to live with somewhat diminished below 35 hz frequency, since the rewards in other respects (purity and relaxed natural quality of sound) was greater. To my ears. Listening over several years, in my 20 x 27 feet living / listening room.
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Why did I say farewell to subs? Was it timing? I don’t think so. I found that the subs usually sounded best when time-aligned, roughly, by positioning them relative to the main speakers. I often ended up with subs and main speakers in a half circle, facing the listening position, or with the subs a bit more forward, to keep up with the front speakers. Was it poor crossover integration? No, I found the best crossover point and slope, and even then, I wasn’t fully satisfied.

Why not? It was the amps in the subs - is my hypothesis number one.

When I got the Velodyne DD18, replacing a pair of more anemic REL subs, I was so glad, I remember saying aloud: "Hello, bassist!" I clearly had more quality sound in the lowest frequencies. But over time, this changed into "Hello, solid-state". Or whatever it was, that disturbed the sound, and made it more tense, with the sub turned on. So to get the purest musical experience I often found myself turning it off. I did not like the "glare" it put into the music, which I associated with solid-state sound.

I am not sure of this hypothesis, maybe it has to do with more conventional problem factors like poor timing or x-over behavior, but I dont think so in my case. It mainly has to do with poor sub amping, compared to the amps driving the main speakers. Especially obvious if you are using top notch tube amps to drive the main speakers, and cheap s-state to drive the sub(s).

Hi Tim
Optional - exactly. I have followed Romeyn’s advice in my own LCS setup, and 95 percent of it was extremely helpful and good. But at some point, it becomes a matter of individual room integration and also listener preference. I do use phase reversal with one of the LCS speakers, it sounds a bit better than correct phase, but I should probably test this again now that I have changed the toe-in of the main Dream Maker speakers. This is, again, an "optional" issue, to my ears. Some like it when they cross in front, some - like me - prefer a more conventional toe-in where they cross behind me. I mailed Jim Smith (author of Get better sound) about this, since in this book, crossing in front is not recommended, it harms the tonality or harmonics. But he wrote back: It is a matter of preference.

Tim, how do you toe-in the Magnepans? Do the speaker axes cross in front of you, at your position, or behind you? I think this matters, also in terms of sub integration. To get my former system time-coherent I had to place the Velodyne DD18 a bit in front of the main speakers, if I remember right. Not a good thing, in our living / listening room. Your Debra system seems much more flexible. Happy to hear it works so well. Maybe I could complete my system with half of it - two subs. Although I have neighbours who complain with too much bass. 

Hi Tim
Nice system - and interesting that we share some of the same experience, listening a bit more nearfield, for the best 3d immersive experience.
Bass and time coherence - I am no expert, just reporting what I heard. I first tried down-firing subs and next came to prefer front-firing ones. First, two Rel subs, didn’t get them to match the system, so next, one big Velodyne. I noticed better sound by positioning the subs precisely in relation to the woofers on the main speakers. But maybe it was room alignment more than time alignment. I did not use REW or other software, but mainly my ears. My audiophile imagination jumped to the idea that time does in fact influence the result. I very much agree with the idea that a main purpose of the sub(s) is to get the room ’in full swing’, smoothness, lack of boom etc. Still I wonder if distance to the subs plays a role also. Even if mainly indirectly / reverberant.Through the room, so to speak.

Hi Tim
Yes, getting some DBA woofers may be an idea, maybe just 2 of the 4, since I already have a bit of distributed woofer / bass extension, using a pair of Audiokinesis LCS speakers along with the Dream Maker front speakers. However I am note sure. I still have some distance to cover, to get the two pairs of speakers to correlate optimally. It is wonderful to be able to do this in the analog domain, not through electronic bad-sounding equalizing. As far as it goes.

Some users prefer the Dream Makers alone, no LCS (or "space generators", a later Audiokinesis term), and I feel happy that I have the equipment to adjust the mix of the DM and the LCS optimally (like you can adjust bass volume and sub positioning on the DBA). For me, it means that the LCS are just BARELY notable. Yet I get better bass, along with a larger sense of air and space.

Since the Dream Makers augmented with the LCS woofers "grip" the room so well, I am not sure of the extra benefit of DBA, though I might be amazed of course.

Another consideration is, this is a living room not just a listening room. 4 more speakers, 8 total? Seems a bit much. I was trying to scale down.