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Our new best friend

Paul's Posts — 13 August 2012

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Our new best friend

Yesterday we learned that our rooms are a necessary element in the stereo system.  It’s good to think of your room as but another component in the chain of your music system and with that thought in mind, we can get comfortable with the idea of working with our rooms rather than working against our rooms.

Our rooms are not the enemies they are made out to be.  In fact, let’s consider our room as our new best friend and get to know her.  I am using the female gender to describe our new friend because our room is the wellspring from which the life and vitality of our music system is going to blossom and thrive.

Understanding that the primary contribution of our room is her ability to reflect sound back to our listening chair helps us appreciate the need to maximize good reflections and minimize bad reflections.  We need both and getting these reflections right is the key to a great sounding music system.

Room reflections happen from any surface in the room but the primary source is the sidewalls.  This is because our floors are typically carpeted, our ceilings and rear walls far away, and our sidewalls closest to our loudspeakers and their reflections pointing right at our ears.

So let’s start roughing in our loudspeaker position with all this in mind.  Using our Rule of thirds we will place the loudspeaker pair approximately 1/3 the length of the room away from the rear wall.  In an 18 foot long room that means we’d place the pair 6 feet from the wall behind the loudspeakers and 12 feet from the wall behind the listening position.   The listening position is, of course, 1/3 the total length of the room from the wall behind the listener.  Note: if this is too far out into the room for your tastes or your family’s needs, use the sidewall boundary method below to determine the minimum distance you can place the pair from the rear wall.  Just stand against the wall behind each loudspeaker and repeat the same process described below.

Place the two loudspeakers fairly close together – perhaps even just a couple of feet apart from each other, giving more than ample space between the outer edge of each loudspeaker and the side wall.

Now, here comes the cool part – the part where we get to know our new friend the room.  Walk over to the sidewall adjacent to one of the speakers and face the wall behind the listener.  If you’ve started with the right loudspeaker, this would mean your left shoulder is touching the sidewall and your right shoulder is pointing towards the right loudspeaker.  Now, start to talk and listen to the quality of your voice – it’s more than likely affected by the sidewall.  What you’ll hear are two things: a reinforcement of the lower octaves of your voice because the sidewall is acting like an acoustic “amplifier”, and a reverberation or slight echo.  If you keep talking and sidestep away from the sidewall and towards the right loudspeaker, this “boominess” and reverb  in your voice will decrease until it sounds like your normal voice, unaffected by the sidewall.  Mark that spot with a bit of tape and then repeat the process on the other side.  Typical distances can range from a couple of feet to three to four.

Next, measure the distance you’ve determined is the point your voice is least affected – average the two distances – and place a new piece of tape exactly the same distance for each side.  For example, let’s imagine on the right side you found that 3 feet was perfect and on the left side you found that 4 feet was right – measure out 3.5 feet from each of the sidewalls and place your tape mark there.

Now, move your loudspeakers so the outer edge of each loudspeaker touches the tape mark at 3.5 feet.  This is a great starting space and here’s the deal: don’t ever go over this mark if you can avoid it.  When we learn how to adjust the distance between the two loudspeakers it’s fine to increase this distance from the sidewall, but we’ll try like heck to never violate this space.

Make sure that your loudspeaker pair are now perpendicular to the wall behind your listening area with no toe in at all.

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About Author

Paul McGowan

Paul McGowan is the CEO and co-founder of PS Audio Inc. a Boulder Colorado design and manufacturing company of high-end audio products and services. McGowan has been designing and building high-end products for nearly 40 years. Hobbies include skiing, music, hiking, artisan bread baking, kick boxing and cooking. He lives in Boulder Colorado with his wife Terri and his 4 sons.

(9) Readers Comments

  1. Geoff1954

    August 13, 2012 at 9:08 am

    Paul,
    Following the room set-up advice with interest. But, many of us don’t have carpeted rooms. Lots of people love hardwood floors and that’s what we have. In addition our speakers sit (and basically MUST sit) on either side of a genuine fireplace (the house was built in 1926). In front of the fireplace is a large piece of stone that is set into the floor, level with it. One speaker sits entirely on the hardwood. The other sits in part on hardwood and in part on the stone. They are Sonus Faber Concertos on stands provided by SF. So two spikes are on wood and two on stone. It might be possible to get that speaker stand sitting on hardwood only but it would be difficult due to the very limited space we have to work with.
    Thoughts?
    Many thanks,
    Geoff

    • August 13, 2012 at 3:37 pm

      Sell the house!! :) No, seriously, you do the best you can. If your speaker are up against the rear wall you’re basically never going to have any real depth and that’s just something you’re going to have to live with. In coming posts I’ll explain how you can tilt back the speakers so they’re not as “hot” on axis as the might be so you get a bit better openness and some other tricks. If floor bounce is a problem are you allowed to put a throw rug down?

      On the brighter side of things I have taken a hardwood floor room that is square, placed a pair of the gigantic Gen 1′s in that room and made them sing – it just takes a bit of space behind the loudspeaker to be available and careful setup. I’ll go through it step by step as best I can.

  2. plasmagod

    August 13, 2012 at 1:23 pm

    Paul, Thanks for trying your hand at setup. I have 3 books/pamphlets on setup from 3 well known names in the hobby and they couldn’t be more different. All have contributed some ideas in my own setups but definitive-I don’t think so.

    One thing nobody has talked about (hardly) in these setup guides is a 45 degree orientation where there are no side walls in the conventional sense and the line between the listener and the midpoint between speaker entends further into a corner. I can tell you that there are significant virtues to this arrangement but I cannot tell you why. I can speculate, but…… I think it would be great if you could think about/test this arrangement.

    Rhett Simpson

    • August 14, 2012 at 6:13 am

      That’s also an interesting challenge – the real trick with anything so unusual is simply getting your head around the various changes and what their affect on the sound will be. I am familiar enough with this standard setup and what works and doesn’t only because I have done it so many times – I haven’t ever played with what you suggest so until I spent time with it I would be of little value. The whole trick is to take notes – either mental or physical notes – and learn what happens when you do this or that and then dial it in.

  3. Geoff1954

    August 13, 2012 at 4:14 pm

    Paul,
    Thanks so much. A little more information: There are rugs and lots of furniture in the room. It’s our living room: sofa, love seat, large padded chair, large leather chair with large leather ottoman, etc.

    Also the speakers CAN come a little further away form the wall behind them (and they are not right up against that wall now). So my other specific issue is does the fact that the spikes of one speaker stand, sit partially on hardwood and partially on stone make a big difference? Could that be ameliorated by the use of vibration control products underneath the spikes?

    Many, many thanks for your help with all these posts. I read them everyday with interest.
    Geoff

    • August 14, 2012 at 6:10 am

      That’s an interesting one – but the more you can do to get the two speakers identical the better your chances are of making them disappear and the image becoming free of them. The ear has an amazing ability to spot differences – however slight – in tonal balance and we hear these differences with imaging changes.

  4. Steve Parry

    August 13, 2012 at 10:55 pm

    Paul, thanks for this and all your posts. I was hoping that at some point you could address any specific tips for those of us with speakers that sound best far into the corners, like my Audio Notes.

    • August 14, 2012 at 6:14 am

      Well, again, I haven’t any experience with such things – but placing something in the corner would be a lot more complex since the corners become acoustic horns or amplifiers and you would have to have speakers that used this horn effectively – sounds like you do.

  5. Soundminded

    August 14, 2012 at 6:49 pm

    It is sound advice to choose one’s friends carefully. A true friend gives as much as he receives. A true friend is worth listening to, not being stifled into mute silence.

    Most American homes built in the last 40 or 50 years consist of rooms built from 1/2″ sheetrock nailed to 2″ x 4″ studs 16″ on center. The floors are cement if the house is a slab on grade, 1/2″ or 5/8″ plywood if they’re built on joists over a basement, floor below, or crawl space. The sheetrock and even the plywood tends to flex and absorbs considerable bass energy. Because of their relatively small dimensions compared to the wavelengths of the lowest audible frequencies and musical tones, these rooms have a cutoff frequency that will further reduce the lowest bass. Most speaker systems have a bass rolloff that begins at around 50 hz or above. What passes for bass is often in the octave or two above the lowest octave.

    Things aren’t much better at the other end of the spectrum either. While the drivers of bass and midrange are fairly wide dispersion over most of their ranges producing early vertical and lateral reflections from the general direction of the speaker, the 1″ dome tweeter with a semi horn recess typically is down 10 to 15 db just 30 degrees off axis from its on axis response. This is usually deliberate. As a result, there are almost no early reflections in the top octave from the direction of the speaker. Room “treatments” which generally consist of sound absorbing materials are geared to flattening reflected spectral response by absorbing midrange frequencies. Geometric diffusers of various types can only disperse sound which strikes them, they cannot reflect sound which is not generated in their direction.

    So what is the net result? Often it is non existant or very weak deep bass, false exaggerated upper bass, shrill high frequencies that are heard mostly on axis. The reflected sound from the direction of the speakers has no high frequency components in the top octave. I have not encountered a single commercially sold speaker system that incoroprates engineered solutions to directly address these problems. Bass and treble controls won’t do it, equalization whether manual or automatic (so called room correction) won’t do it. Midrange and tweeter level controls won’t do it.

    About all that’s left to audiophiles to adjust their sound is to nudge the speakers around the room, experiment with various diffusers, keep buying and swapping amplifiers, preamplifiers, wires, speakers, cd players, phonograph cartridges and purchase expensve magic bullets like wire tees, special connectors, vacuum tubes dunked in liquid nitrogen and the like. The more bizarre the bullet, the more improbable the explanation, the more audiophiles seem to flock to them. Does it work? If it did, would audiophiles keep swapping equipment all the time? And it does seem to get more an more expensive all the time. I don’t know. Maybe audiophiles just like spending money and keeping dealers and manufacturers profitable.

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