Optimizing the bass response of an audio system is well worth the effort, as most audiophiles will attest to. It requires an initial investment of a little time and effort, but will yield countless hours of enhanced audio satisfaction and hi-fi pleasure.

    It has been noted that the bass frequencies in a reproduced piece of music can constitute approximately 30 percent of the overall audible spectrum. Now, if I was driving down the road at a moderate speed, taking the bends comfortably and making good progress and my passenger leaned over and yanked on the steering wheel for just one per cent of the journey, that would be enough to drive me crazy. If they did that 30 percent of the time, I know I wouldn’t be thinking sweet thoughts about them and I would be seriously doubting the likelihood of safely arriving at my destination.

    This may be an extreme analogy, but one that makes the point obvious. Sometimes the control of your vehicle is taken from you in ways that are less perceivable, but have a compound effect: examples could be wrong tire pressures, or incorrect wheel balancing or alignment. They may not hinder your driving pleasure to the point that you just don’t want to bother with the trip, but, once these issues have been remedied, you never want to go back to driving the less-well-maintained Jaguar.

    Monitor Audio Silver W-12 subwoofer.

    Monitor Audio Silver W-12 subwoofer.

    Managing our bass in our hi-fi systems can be similar. We may have a great “vehicle” – our speakers – but without tuning our bass we are likely missing out on the smooth pleasure cruise.

    I have been as guilty of this as anyone. In my attempts to improve my system’s bass I started researching what some of the professionals were saying on the matter. In one interview with Andrew Jones, eminent speaker designer for ELAC and previously Pioneer and others, he related a concept that appealed to me. He was saying that to obtain a properly immersive sonic experience with enough bass produced using full-range floorstanding speakers, you would need a minimum of seven of them to get the desired effect. This was very interesting to me because at the time, I was already running a quadraphonic floorstanding tower system with a single 8-inch bass driver in each speaker cabinet. Would I need more towers?

    It seemed like I was on the right track, but as much as I would have loved to populate the room with more speakers, there was no way I could accommodate seven or more in my room and get away with it. However, according to Jones this was what would be required to eradicate any nulls in the room’s bass response. But I already had plenty of bass drivers in my setup. What to do?

    Given that the room itself can account for about 50 percent of the system’s sonic behavior, since it has areas of bass cancellation and reinforcement and influences the reflected and absorbed sound so much, then it seems to make practical sense to take active steps to claw back more control of our audio once we have set it free to roam around the room.

    Additionally, sometimes the shortcomings of our hi-fi systems are hard to notice at first, but once they have been remedied, there’s no going back. To name one important example, let’s talk about dealing with the dips in our in-room bass-frequency response.

    I was semi-resigned to the fact that I could EQ my speakers with a suitably gradual ramped bass slope and make do with that. After all, the bass was sufficiently loud enough and even complimentary to the resultant sounds in my music. Surely then, I didn’t need a subwoofer, right?

    However, I should tell you that I have some absolutely excellent friends, and one of them, in a typically self-deprecating manner, gifted me a new subwoofer as what he called “a belated wedding present.” What a guy! Thank you, Laurence.

    I then came to appreciate the many considerations and benefits from using a dedicated subwoofer, or multiple subs. In fact, studies have shown that using multiple subwoofers can be more beneficial than using just one, but many if not most of us don’t have the room and/or budget.


    Placement options for a four-subwoofer setup. From the GIK Acoustics website.

    Placement options for a four-subwoofer setup. From the GIK Acoustics website.


    One, the sub has been specifically designed from the ground up to handle only bass frequencies, with good bass extension and without struggling to do so. Two, the subwoofer typically has a built-in power amplifier that is optimized to the driver. Three, a subwoofer can be placed very specifically in the room. Four, it has dedicated controls for gain (volume) crossover frequency and phase. Five, in a home theatre system it specifically reproduces the LFE (low-frequency effects) channel, which can result in a cleaner overall sound. But most of all, a dedicated subwoofer can provide an omnipresent and enveloping low-frequency effect, and when properly dialed in, can magically disappear in its support of a more realistic soundstage. For those who don’t think they need a subwoofer in their stereo audio system, consider the fact that with certain speakers and rooms it may in fact revolutionize an already good-sounding system into something awesome.


    Rear panel of a Klipsch Model R-112SW subwoofer.

    Rear panel of a Klipsch Model R-112SW subwoofer.


    When you think about the bass amplifiers used in a recording of a band you enjoy listening to, or if you’ve seen them live, likely the bass player was either using a cabinet with a 15- or 18-inch speaker, or multiple 10-, 12-, and 15-inch drivers. That’s a lot of moving air. And live, the bass guitar is also run through the PA system. That’s really a lot of moving air. Then we have the drummer’s kick drum and tom toms and maybe low frequencies from the synth players. Many if not most speakers just simply do not reproduce the bass frequencies at anywhere near 20 Hz, generally considered the lowest frequency of human hearing. Orchestral music also has a lot of low-frequency content.

    In the same way that the musicians and engineers who created the music have controlled what bass you hear on a recording, you too can control the bass response in your room. With a good quality subwoofer or multiple subs, you can use the controls they are equipped with and take back control of the steering wheel in your musical journey.

    In a coming issue, we’ll give tips on setting up and placing subwoofers in the effort to maximize your listening pleasure. You may be surprised at how simple it can be to get greatly improved results without spending much time or money. Becoming submissive to the merits of bass management can be empowering.

    Header image: The REL T/9i, subwoofer royalty!

    9 comments on “Sub Missive”

    1. Brilliant article. Really looking forward to the follow up. I know its pretty low end compared to what your readers probably own and use. I have an old Tannoy TS10 sub in the studio to complement my old Tannoy Reveal Active (blue) monitors. I will def purchase a decibel meter to measure the rooms nodes and anti-nodes etc. What I can say is that using the TS10 with my near-fields with the crossover set correctly/incorrectly took away the pressure on the near-fields to reproduce the low end, hence cleaning up the sound. Further (I may get scorned for this), I plugged the ports of the speakers with clean rolled up socks to minimise the resonant frequency enhancement made by the port. Yeah, on warm days I remove the socks lol but the speakers have been running for 18 years. I look forward to the follow up to this article.

    2. Don’t forget that a really good “decibel meter” is available with your iPhone and some pretty cheap software. Audiotools by Studio Six Digital.

    3. I own a quod of Avantone Pro CLA-10 Studio Reference monitors.
      For awhile, I ran them in parallel with my vintage Fisher 800 receiver.
      I do this because I make recordings with this system.
      But I needed to hear the bass a little more clearly then I was hearing it.
      But giving the fact that Avantone doesn’t offer and or make subwoofers, I started looking at JBL pro monitors.
      I picked up a pare of JBL LRS-310S powered subs.
      I stuck each one under each pare of CLA-10 monitors.
      I can’t see because of what happened to me almost 29 years ago, but that’s another story for another time.
      So I fine tuned the whole entire system by ear.
      I was able to turn the bass control knob on the receiver down to the 12:00 position.
      I turned the volume on each sub up 10 notches to get a tite blend in with the monitors.
      Long story short, it didn’t matter what I was playing on that system.
      Either way, it sounded like I had the singers and musicians in my bed room, right there in front of me.
      I don’t remember the guy’s name that I spoke to over the phone at Sweet Water.
      But he tried to tell me that I didn’t need but one sub.
      But if you’re blind, then your hearing abilities are gonna be way better then your sighted counter parts.
      In most cases, you’re gonna have 3D hearing.
      And your ears aren’t gonna be happy with just one sub.
      I hear everything in 3D.
      I’ve heard those 5.1 surround sound systems.
      They say that you won’t be able to locate the subwoofer by listening for it.
      But how come I can locate it every time, and walk right up to it then?
      I’ve asked lots of people that question.
      Some of them, being audiophiles.
      Would you believe me if I told you, they couldn’t answer that question?
      I tell you all this, two subs are in deed better then one!

      1. The reason you are hearing them in 3D is they are providing surround sound as satellites to the main speakers. REL’s John Hunter has a lot on REL’s website about this.

        If you are also wired in stereo with both subs that has a huge benefit in making the subs disappear along with the main speakers. Blending them all is what audiophiles do.

    4. I imagine if you had subwoofers with perfect low pass filters, no cabinets, and no other physical components, you would not be able to locate them by sound. I believe they are bound to produce attenuated but still audible overtones due to crossover deficiencies and sympathetic resonances. I supplement the sound of my Maggie’s with two small subs (TBI brand) one in the corner behind my R speaker and the other near the left side wall. Most of the room is free of boominess, and I’m pretty sure that another sub or two could largely eliminate the current deficiencies l

    5. I believe my needs are different from the usual ones in the bass part of the audio spectrum, but certainly not unique. I’m thinking of getting a pair of KEF LSXs for my computer. They’d be placed on my desk top, and I’d like to add a subwoofer that would have good response down to 30 Hz or so, at least. What I need, then, is nearfield response, not room-filling, at only low to moderate volume, I’m guessing that this might be done with an 8″ woofer with Fs ≈ 25 Hz, in an enclosure with a port or a passive radiator. AudioXpress magazine had plans (not too well delineated, and using a driver that’s no longer available) a short time ago. Are there any commercial versions of such a speaker?

      1. One that will work very well in a desktop situation will be the KEF KC62 sub. It was just reviewed professionally.

        Or if you want a sub that costs less than that of the LSX, the REL T-Zero is still fantastic for that application. Two would be even better, run in stereo. (REL has a sale on right now. Not great, but better than nothing.)

        You may also want to check out the latest videos on their YouTube page. It directly answers the desktop need, as well as two models that you may or not find too expensive.

    6. Multiple subs are best run in stereo pairs, not mono (or at least the fronts behind the main speakers). Didn’t see a whole lot of discussion on stereo operation of the subs. Hope it comes in future essays.

      Stereo subbing with 2 subwoofers has the massive benefit of adding those 2 subs as surround sound satellites, albeit without many of the drawbacks of having surround sound speakers placed near a wall.

      Hearing the additional space fill in and around the main speakers with additional depth and width cues adds to even dipolar speakers like Magneplanars.

      One poster spoke of a 3D presentation. I agree. Stereo subbing with multiple subs gives that. A 3rd sub will address room nodes, and the same applies to 4.

      There is no going back indeed. The additional bass information leads to greater treble extension as well. Believe it or not, it is obvious to hear once the subs are turned off and then turned back on again. It is not subtle.

      1. Good morning Jeff!
        I didn’t say this in my post yesterday, but I’m so glad that you figured it out!
        That’s exactly how I’m running my JBL LRS-310S subwoofers.
        I am in deed, running them in stereo.
        I don’t know where that guy’s head was at Sweet Water, but he totally didn’t get it.
        What I’m doing now, I also done this 23 years ago.
        I started out with one, but my ears weren’t happy with that setup.
        And so, I went back to the stereo store in the maul here in Lake City Florida, and bought another sub just like the first one that I started out with.
        But when I rearranged my mane speakers and stuck a sub underneath each one and wired them up in stereo, the sound stage came alive!
        I am now doing the same thing with my pro studio monitors.
        That guy at Sweet Water, didn’t know what he was talking about.
        You only need one sub?
        LOL what a laugh!

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