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Help! Subwoofer Newbie Problems!

Folks,

I’m new to subwoofers (having usually hated subwoofer set-ups almost anywhere I heard them).

However, I’m trying to downsize a bit from my Thiel 3.7s to the smaller 2.7s, and I’m trying out a couple JL Audio E-Sub e110 subwoofers with the 2.7s.

I have very little time to evaluate them before deciding to send back for a refund, so it’s a quick and dirty set up, just to see if I hear anything promising.

I’m using Conrad Johnson Premier 12 140W/side tube monoblocks, and the CJ Premier 16LS2 tube preamp.

I want to at least first try running the speakers full range and crossing the subs over at a lower crossover. So I’ve started by running speaker wire from the Thiel’s speaker terminals back to the subs high inputs. This is the way REL subs are usually set up IIRC.

First results (after dialing them in a bit), is that, yup, there’s subwoofers in the system. Lower lows. But it’s also really changed the sound. The good part is that the sound seems more spacious, rich and 3 dimensional. In that respect, they start competing with the larger 3.7s. However, there’s also obvious tonal change - the system now sounds a bit rolled off, darker, more full and lush in the mids, but also distinctly softer with transients being softened. It looses the energy factor.

I’m wondering what accounts for this tonal change. The subs are active, and so as I understand it, having them share the speaker terminals with my Thiels shouldn’t be drawing anything more from my CJ amps and making them work harder or anything. So...what gives?

To try and check this out, I’ve just received long RCA interconnects to try connecting the subs via my pre-amp outputs instead. This gets me into confused newbie territory.

My CJ Premier 16LS2 pre-amp has two sets of outputs. I have presumed that I just keep one outputs sending to my CJ amps as I normally do, and simply run the L/R signal of the second pair of outputs to the subwoofer RCA inputs (making one sub L and one sub R).

Problem is: I don’t seem to be getting any sound out of the subwoofer this way! If I use the speaker line high level inputs from my Thiel speaker terminals, I clearly get the subwoofers working. When I unplug those and send the line from my CJ pre-amps second outputs....nothing.

Any advice?
prof
prof OP
1,741 posts
 
Great responses, thanks!

snapsc,

I like my Conrad Johnson tube preamp/amp too much to switch to solid state.  Every time I've tried SS I've run back to tubes.  Learned my lesson.  (I believe the crossover I'm going to use will pass along the character of my pre-amp ok).

Jon,

Your experienced input is valuable.

The ability of my CJ preamp to drive the signal over long runs of interconnect are a bit questionable.  That's one way adding the JL CR-1 crossover helps, which will drive things no problem.

My listening room was designed with the help of a acoustician, so it has treatment, trapping, sort of "built in."  It's a great sounding room (and a wide opening to one side into the hall seems to stop a lot of bass room-node wave build up - the big Thiel 3.7s for instance sound perfectly even in the room).  I won't be adding any more room treatments.

I've considered going with a good mic and computer software to read the room, but I'm trying to make this as user friendly as possible.  So I'd first probably go to items like my Velodyne SMS or an Anti-Node, to dsp the subwoofers.

I'm still curious if subwoofers can actually be added in a way that doesn't alter the general tonal character of the main speakers.  After all, adding frequencies anywhere does tend to have a psycho-acoustical effect in how we perceive the sound.   As mentioned, my bigger Thiel 3.7s go lower than the 2.7s, and preserve the Thiel sonic character I'm looking for.  Except they are aesthetically larger than I want in the room.


willemj
1,036 posts
 
I added a sub (B&W PV1d) to my Quad 2805 speakers, and it did not change the sound of the main speakers, but just added to it. In my case the larger Quad 2905 were simply too large from an aesthetic point of view and adding the sub turned out to be a good alternative. Without the Antimode 8033 integration was less than perfect, with quite a bit of boom, even in a large room. With the Antimode, it is much better, even if I have decided a second sub should improve matters even more, and add extra power. My (quite inefficient) Quads are now driven by a 2x140 watt Quad 606-2 amplifier (earlier I had a 2x45 watt Quad 303 and that was not quite enough). The extra 400 watts from the sub gave even more power for a cleaner sound, but I can use yet more for dynamic music like symphonic music.
prof OP
1,741 posts
 

Good info about the anti-mode, willemj.

I've heard that it's not quite transparent enough for some people when used over the entire system, but works well on just the sub signal.  Sounds like that set up worked for you.
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