Subwoofers and full range speakers

May 23, 2022
 by Paul McGowan

8 comments on “Subwoofers and full range speakers”

  1. I think I have a minor difference about directionality in the bass. I believe it’s non-directional higher than Paul does. I recall a listener standing right next to a set of subs crossing at 65 Hz and telling the demonstrator the subs weren’t working. The demonstrator had to take the sub grills off and allow the listener to feel the subs pumping away. So I suspect non-directionality is even a bit higher than even that 65 Hz.

    Also I am a fan of subs with high pass filters for the main speakers, at least when the filter is designed to integrate with the main speakers. I have a custom set up with 18″ subs crossing at 85 Hz with a 4th order LR filter. And by adding the sub the main speaker significantly opened up due to it not having to work nearly as hard as when it went full range(the mid 40s I believe in my case).

  2. Now that you have focused on subs recently and at the risk of sounding stupid, can you explain how to connect subs in a legacy 2 channel setup?

    1. Hello, well as usual, it will depend. Do you have preamp outputs or only speaker level outputs. Many subwoofers have both as inputs and a specific LFE input (most receivers have that LFE output these days, some even have two, for adding two subwoofers if you want). For a legacy 2.0 stereo you can use the preamp outputs (if you have them) or speaker level outputs, which of course you would have. (Then the speaker level outputs from the sub go to your left and right speakers).

      There are lots of YouTube videos on this if you search for “How to connect a subwoofer”, but my advice would be to download the manual for any prospective subwoofer you are interested in, such as a SVS or REL, for example, and read through their instructions.

      While using speaker level outputs can work in a pinch, I believe they are a compromise at best and might introduce a small amount of additional distortion, but if that is your only option well, there you are.

  3. Rel had a great take on *integration* with main speakers.
    The combination of sub level and crossover is experimental, but can be dialed in quite easily.

    I use a single Rel T/9i slightly out of a corner, and firing diagonally across the longest dimension of the room.

    I did experiment with a hi-pass setup on the main amp, and found I had better integration with the mains running full range. I turn the Rel off on occasion just to see how capable my ported mains ( with foam “bungs” in the ports (a separate port for each 6.5″ driver).

    If I had anything less than awesome bass, I would add another Rel.

  4. It must be at least 5 years ago when I started reading Paul’s enthusiasm about augmenting full-range speakers with subwoofers. It was enough to inspire me to purchase a couple of subs for my 2-channel system. I wasn’t confident enough about selecting a good match for my B&W 800 Diamonds so I went with the then B&W offering of a pair of DB1s (class D, 1000W-powered, 12inch, front and rear drivers). I used the recommended set up, connecting them to the preamp and with a crossover of 80Hz. The results were very satisfying. I’ve moved house a few times since then and each time (not surprisingly) run into room mode issues but put up with them promising myself I would address them when I settled in more permanent accommodation.

    Recently, Paul’s spoken a few times (including today) about ‘near-field’ subwoofer placement after experiencing this at Darren Myer’s house. I was intrigued so I re-arranged my set up, placing the subs on either side of my listening position. In short, the improvement is startling! The room modes are attenuated and the time alignment has greatly improved. It was as hahax wrote above, the effect is so transparent that you really wonder if the subs are actually working!

    If you too have been wondering about near-field subwoofer placement, I heartily recommend you try it out.

  5. If you look at the frequency response graphs of most full range speakers there’s a steep drop off from it’s stated low end extension. Only a true subwoofer can fill that gap flat to 20Hz and below and fill the room.

  6. At 50hz LP/HP crossover (12db per octave) between my stand monitors (flat to 38hz) and powered sub (flat to 18hz), the blend and hand-off are absolutely transparent, seamless and fast. With the lowest bass relieved from the monitors and stereo amp, overall, I have 5-6 db more headroom and output with less distortion, better transients, more punch and an ease of playback in the upper bass and lower midrange…a win-win all the way around!

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