SVS | Subwoofer Placement

Speaker placement for improved sound

Written by Published | Rapallo AV Team

Estimated reading time: 9 minutes

Speaker placement for improved sound… many people assume that the only way to improve the sound they hear from their speakers is to change something around in your system.

A new DAC? Sure, that might work. A better amplifier? If you can afford one, absolutely! Amplifiers are important in your AV system. Perhaps a new pair of speakers altogether? Definitely an exciting idea, but there could be a much simpler solution to this problem.

An often-overlooked fact is that aside from the technology inside a pair of speakers, slight alterations to their positioning within a room can make dramatic improvements to the overall sound.

A lot of articles on speaker placement assume an ideal situation of a perfectly rectangular room. For most people reality is a little different and chances are that you will have to work with something that is a not quite so optimal situation.

Acoustics will be different in no matter which room and a good pair of speakers that are well designed will allow for that.

For a home theatre that moves beyond a simple sound bar, we would advise to have at the very minimum a 5.1 set-up for a good discrete surround sound system.

Let us stress that we are big advocates of doing a 5.1 well, rather than opting for a 9.2.4 full out Dolby Atmos that is done ‘on the cheap’ and riddled with shortcuts.

Don’t get us wrong, we’re by no means saying that you should not have dual subwoofers (we would never say that!) or height-effect speakers for Atmos (we have them too!). We’re just saying that you shouldn’t compromise on quality for the sake of quantity. And since most of us are working with a set budget, that’s where the priority should lie in our opinion. End of sermon.

A few of our suggestions to start off with:

  1. Start off by placing your chair or sofa nearer to the middle of the room and not too close to the back wall.
  2. This might sound obvious… but avoid placing items directly in front of your speakers! You would be surprised about the amount of times we’ve seen DVD stacks the size of The Eifel Tower in front of speakers or hidden away in corners surrounded by furniture. It’s a sure-fire way of distorting the sound and ruining the listening experience!
  3. With a few exceptions, it helps to leave space between the wall and the speaker. You will notice an improvement in your mid-range and mid-bass.
  4. If you’re thinking about a surround sound system, we recommend you place your subwoofer at least 30cm from a corner to prevent unnecessary reverberation and echo.
  5. If you mount your speakers on a shelf it is best to place them on a layer of foam or a similarly absorptive material. This prevents the entire desk from reverberating and helps isolate the sounds you actually wish to hear from those you don’t.

Setting up front left and right speakers:

Below we give you some steps to go through to decide on the best position for your front left and right channel. We admit, it does take a bit of practice to get it right as differences can be subtle. Don’t let it scare you off. The result will be worth it.

Here’s how to tackle this:

  1. First of all, place your speakers right up against the wall, flat out (not toed in), and the appropriate distance apart (usually 1.5 – 2.5m depending on relative listening position and aesthetics).: Dolby recommends an equilateral triangular placement for the front left and right speakers. This means the speakers are placed equally away from the listening position
  2. With the speakers in this position listen from your primary seating position to a relatively detailed, familiar 30 second part of a track that is representative to the sort of thing you like to listen to –  the more familiar you are with it the better, as this will help you decide what sounds best.
  3. Start moving each speaker out from the wall, 50 millimetres at a time or so and repeat the process with the same part of the track as a comparison – the sound will be usually be slightly better.
  4. Next move the speakers out another inch or few millimeters and repeat the process again – the sound will probably be better again.
  5. You will eventually reach a point where the sound starts to get worse, rather than better, as the distance from the wall gradually increases, step by step.  Put the speakers back in the last position before the sound started to get worse (where they sounded best to you) – this is the correct distance away from the wall for your tastes.
  6. Repeat exactly the same process with varying degrees of toe in.  You will find that as you toe the speakers inwards, step by step, at increasing angles of toe, the sound will get better and better, and then worse again as they become toed in too much.
  7. Place them back in the last position where they sounded best.  This is the correct degree. We should note that some manufacturers develop their speakers so that toe-in is not required, so the following will also vary depending on speaker brand.
  8. Also, it’s good to keep in mind that it takes time for speakers to be ‘run in’ and that sound characteristics from the speakers will change and require re-positioning after they are run-in.
  9. If you use bookshelf speakers, you want to put them on speaker stands so the tweeters sit at ear level when sitting down.

Setting up the centre channel

While underrated, the centre channel is arguably the most important speaker in a surround sound system since nearly 70% of all audio playback comes through the centre channel at any given moment. It also handles the majority of vocals and dialogue in music and movies and ties all the action together across the front stage to create a palpable sense of realism. Proper placement is important because it tacks the vocals to the screen, and also allows effects to flow without breaks from left to right, allowing for the suspension of belief.

  1. If using a projector and an acoustically transparent projection screen, installing the centre speaker at ear-height behind the screen makes for ideal placement.
  2. Often, centre speakers end up living on top of an entertainment cabinet or easily on a shelf mounted above or below the TV screen. Just make sure the speaker in angled up or down towards the listener if they are not at ear-level. If in any way possible, aim for ear-level.
  3. For a large centre channel that won’t fit in a piece of AV furniture, try stand mounting at ear level below the screen.
  4. Always place the centre channel speaker as close to the screen as possible, whether in front or behind.
  5. If placed on furniture, align the speaker flush with the front edge to eliminate lobing of the sound waves which can negatively impact clarity and dynamics.
  6. When setting the angle below or above a screen, a laser pointer held against the top of centre speaker can be used to accurately aim it to ear level in the main listening position.

Setting up surround speakers

Surround speakers are placed very differently in the room so while it can be nice to have the same brand, it is not as crucial as with the 3 front speakers. That said, you do want to make sure that the surround speakers provide very similar dynamic capabilities.

Unlike the three fronts, the surround speakers are used to create a cloud of non-localized sound that envelops the viewer. Side speakers are best placed beside or a few feet behind the main seating area and a few feet above ear level so the surround sound is not too easy to localize.

If you prefer a diffuse sound field, bi-pole (in phase)/di-pole (out of phase) surround speakers are the way to go. If your choice is to have more localized information, we recommend monopoles. With more and more people choosing to also have rear channels as well, di-poles and bi-poles tend to be not as popular as they used to be.

Rear surround channels in a 7.1 set-up are placed again a few feet above ear height and slightly closer together than the front speakers.

Setting up the subwoofer(s)

Subwoofers are a very different cattle of fish compared to other speakers.  As we mentioned at the start of this blog, things are rarely ideal, and like the rest, subwoofer placement often involves compromise.

Sometimes there is literally ‘one spot’ for the subwoofer. Don’t feel badly if this is the case – it’s very common for mixed media audio systems to be located in a family room. Everything in the room is competing for available floor space, and décor is often significant considerations too (Sigh, we know…).

If you are limited to a single subwoofer location, just try to find the best listening location in the room. If you can’t move the woofer, maybe you can move the seat? You’ll notice as you move through the room that the bass response will vary significantly. As we have explained in previous blogs, you can blame the complex pattern of direct and reflected standing waves for that.

Sometimes simply moving a few feet in any given direction can improve the bass from boomy and one-note to balanced and accurate. Once you find the ‘subwoofer sweet spot’ in the room – reserve that seat for yourself!

But you may be lucky and have more flexibility with subwoofer placement, with 3-4 potential locations usually available in dedicated home theatres.

A good place to start is up front. Subwoofer placement in the front of the room usually results in the best blending with the main speakers and centre channel and minimizes localization effects.

Try a corner first. Corner placement excites all possible room modes, resulting in a denser standing wave pattern in the room. This reduces (but doesn’t eliminate) the potential to encounter nulls, which are acoustic cancellation points or ‘dead spots’ in the room.

 If corner placement on the front stage sounds awesome – consider yourself lucky and kick back to enjoy some music and movies!

If that doesn’t result in optimal bass response, there is always the ‘subwoofer crawl’ technique. This involves the following steps:

  1. Place the subwoofer near your main listening position. Loop a familiar soundtrack with a repeating bass line.
  2. Consider the options you have as far as subwoofer position goes  and listen for the result in each one. Keep your head at knee level while you do this (hence the term ‘subwoofer crawl’)
  3. Put your subwoofer in the spot that provided the best result as far as balanced and accurate bass goes.

Despite all your efforts including subwoofer placement, bass trap positioning and the help of auto EQ, a single subwoofer will never have an optimal frequency response at all listening positions in the room. Especially in larger rooms with multiple rows of seating, this can especially be a real pain.

The solution is upgrading to dual subwoofers: it greatly increases the modal density in the room, resulting in a smoother frequency response at more listening positions in the room, with less potential for obvious peaks/nulls in the frequency response.

But that really is a story for another time…

Have fun tweaking your set-up!

The Rapallo Team

Sources: Cambridge Audio, SVS, Audioholics, What Hifi, AVS forums