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  • DJ

    Great advice! Very well written and informative!

    • Hi Dave,

      Thanks for your feedback and I’m glad this article had value to you!

  • Romina Jones

    Interesting you always hear about pulling the speakers away from the wall 2 feet or more but here you say it can make matters worse. In a small room this can be hard to do so it is reassuring to hear you talk about pushing the monitors close to the wall and work around the reinforced bass that this results in.

    • Hi Romina. Always be wary of sweeping generalizations. It depends on the directionality and low frequency cut-off of your speakers.

      Two feet may be manageable using simple bass absorbers, while four feet (which causes a cancellation notch at 70 Hz) is much harder to manage if your speakers have a LF cut-off below 70 Hz. You can still reduce a 70 Hz cancellation notch, but the bass absorption technology needed is more expensive.

      There are many factors at play, so you need to consider the actual physics. A rule like “2 feet or more” is not much use without scientific or experimental validation.

      If a manufacturer did a bunch of tests and concluded that 2 feet or more works best for their speakers, that’s certainly valid.

      Otherwise, best to use the LF cut-off and directionality of your speakers to help you decide.

      • Romina Jones

        True, I have KH 120s for near fields and the manufacturer distinctly says avoid .8 to 2m (2 to 6 feet from front wall). Ergonomics and symmetry wise it would work great if I COULD place them within that distance in my oddly shaped mix room. Nonetheless I have Room EQ wizard and once finished my acoustic treatment will run the program.

        • Those numbers make much more sense. And I understand your frustrations. It’s a pain that aesthetics and acoustics are often at odds with one another.

          I wish you the best with your room. :-)

  • Saschwell

    Great guide! Not to hard to understand even for me as a beginner. I’m planning on adding a subwoofer to my two monitors and I am not sure where to place it. My listening position is facing the short wall (about 2 meters) and the long wall is about 3,5 meters. It would be great if you could give me some advice where to place (or try to place) the subwoofer. :)

    • Hey, glad you like. :-) For a single subwoofer, a good starting point is to place it close to the front wall, to the left or right of the room’s center line. That’s what I recommend you do to start. To find the optimal subwoofer location you would need to use acoustic measurements: I.e., move the subwoofer around and look at the frequency response in high resolution (looking for the location with the flattest frequency response).

  • Martin Merayo

    Hi Tim, great article! But i have a mind boggling doubt about it. i have a room where the lenght is 5,90m so my 38% listening spot is 2,24. So far so good,but when i place my speakers while sitting in that spot they fall in the 1-2,2m zone that you recommend to avoid to treat the SPBI! So what would be the solution since i can flush them into the wall? Should i place them in the closes/1m Range your recommend? This seems like the logical solution, but if i do that while sitting at 2,24 in my room i will have my speaker like 2m away from me to keep them close to the wall. So, what would you recommend in a case like this?

  • Martin Gregory

    It might be worth noting that the animation of sound reflecting is charting pressure not displacement. Maybe this will only matter to people like me who are overthinking it :)

    • Great suggestion Martin. I can see how it would look wrong if someone thought they were looking at a true depiction of a sound wave (since sound waves are longitudinal) or a chart of displacement, which would be zero at the wall.

      I’ve reworded it for clarity. :-)


  • MacINtyre

    Awesome stuff! Just one question to clarify: When you say your mains (that aren’t flush mounted) should be at least 47″ off the ground, and it didn’t seem to apply to 15degree down angled mons., is that from the top of the monitor to the floor, or to the bottom of the monitor to the floor?


    • Glad you like it! That height recommendation is for your tweeters or mid-range drivers.

  • Thomas Garnett

    is the front wall the wall closest to the outdoors?

    • Font wall just refers to the wall in front of the listener / behind the speakers. It could be an interior wall or an exterior wall, but it’s worth noting that speaker boundary interference would be stronger if the wall is well isolated. A thick exterior wall would reflect more bass energy than a lightweight interior wall.

      Or to give an extreme case, a soundproof room will have high internal reflection and therefore lots of boundary interference, while a sound-transparent tent would have virtually none.

  • bear

    my room is square and has a window in it should i make the window wall be behind the speakers

  • rodrigue

    hello, if i flush my monitors into a wall should i stay at 38% from the original wall or from the new wall i just build?

  • Chris mayo

    Hi Tim just discovered your website and I have found it very useful and very informative. I have one question for you, do the same calculations apply for the Barefoot micromain 27s mounted sideways on the Sound Anchor stands, as the Lf drivers are firing up and down?

  • 김진식


  • Jm

    Trying to figure this out for my studio, my “front wall” is wall-to-wall windows starting halfway up, with a light-blocking and some sound blocking motorized shade. My room is about 10″ wide x 12″ long x 8″ high, but it also has 2 load-bearing square concrete columns embedded into the side walls about 4-5 feet from the front wall. The problem is one of the columns sticks out about 6″, the other sticks out 10″. These columns make me want to center my setup between them, which would then make offset to the right instead of perfectly centered. Help?

  • Andrey Nagovitsyn

    Why not just mount sub woofer in a wall, this gives some freedom on placing satellites around the room. With mounted full range loudspeakers we have one and only one place of sweet spot.

    • Marco Stanzani

      Right! I am going to use TWO subwoofers for this. Neverthless I will place my speakers using the golden rule (see cardas site)

  • henry gomez

    Actually, start applying acoustic treatment as soon as you can. Your first priorities are to treat your first reflection points and place bass traps in as many corners as you can. And if you need well defined website for your business, connect with Website Design UK.

  • Armand Vermeulen

    Very informative article! Thank you

  • davidrmoran

    Some clarifications.

    Higher SBIR problems can be nicely addressed with staggered placement of the woofer, which is hinted at here but not explicitly explained with placement near one boundary. In other words, you can very much smooth the common satellite-type lower-midrange notch (in the octave below middle C — NOT the bass!) with placement 2′ x 3′ x 4′ or 5′ from the near corner. The worst case of course is identical distances from the near corner. This solution to the Allison effect, as it was long known well before SBIR, is effective. Otherwise, yes, it can indeed be partly EQed out (filled in), since this is a room-power notch (resulting from changed air pressure on the cone surface from the reflected impedances) is rather more location-invariant than not, unlike room resonances.

    It is crucial furthermore to understand that this is NOT LF. Observe the power suckout graph above with the notch at around 130Hz. That’s the C below middle C. Go to a piano and play it and see if anyone would label that bass. It is common for the Allison effect to lie higher than that, as well.

    It might also be useful to go more into the ear’s integration, how in domestic rooms there is no such thing as direct sound below a very high frequency (well above middle C). Just calculate the wavelengths, periods, and time in milliseconds for all of the combo sound to get to your integrating ear when seated a few feet from the speaker, and it should become clear. Keep this in mind when someone speaker of ‘direct’ sound at say 220Hz. How many cycles have occurred before it registers at your ear, which is an averaging detector that requires considerable time to make its determinations?

    Finally, you want to distinguish in this analysis among (1) coherent reflection summing (LF, sub placement in corner, all good, maximally driving room resonances, w/ possible LF treatment a la Winer for audibly bad situations); (2) much higher (midrange and treble) summing where it does not matter and the ear does not care except when a tweeter is near a boundary and there results a nasty peak; and (3) this lower midrange Allison effect area in between, where the wavelengths are similar to the distances to the boundaries.

    Studying the extensive Allison scientific writings on this physical phenomenon is enlightening for anyone placing or designing loudspeaker systems.

  • Mike Lloyd

    What about rear ported speakers? Are you suggesting that rear ported speakers still be placed in, or as close to, the front wall?

    Love your site BTW, astoundingly informative.

  • Javi Ramallo

    Thanks Tim!

    Amazing information here!

    Was very very useful for me!!

    Really thanks!

  • Sebastian K

    You wrote that SBIR can not be corrected by eq, because if you boost the notch it will also boost the interfering wave that’s returning from the rear wall after bouncing. But what if I lower everything else so that it matches the notch? After doing so, the decay time in the place where the notch used to be will still be shitty, but I will have my frequency response corrected in exchange for volume, is that correct, or am I missing something?