Kvalsvoll Design AS About Products & Services Sound! Logo


How to set up a Home Theater Sound System

26.03.2014: Minor updates for Room acoustics.
06.01.2015: Info for new immersive sound formats Dolby Atmos, Auro3D, DTS:X.
20.08.2015: Revised version. Updated content, more images, more on acoustics.

<- Previous: The Theater Sound Experience


How do you want it

First, find out what you want to achieve. Not only by deciding what kind of sound you want, but also keep attention to the intended purpose of the room, as this will affect choices for gear and placement.

If you have never experienced movie sound other than from an ordinary cinema, it would be wise to demo a really capable system, this can give you some clues about what you should prioritize in your own set-up. Remember, something that has not been experienced will not be missed, and this is especially true with movie sound.

You will have to make decisions and compromises to suit the needs of your room and your budget. Interior styling preferences and practicality will also set limits.


Consider to prioritize what you believe is important for your theater:

  • How loud?
  • Clean sound most important?
  • Surround sound from as many speakers as possible?
  • Subwoofer capacity - only subtle or tear-down-the-house?
  • Sound coverage across all seats?
  • More than one or two viewers - then a center channel will be very much desired

These parameters, along with room size and visual appearance considerations, is the foundation for the requirements of the sound equipment.

Room size is important because it takes more sound energy to fill a larger space, which will affect requirements for speakers.

Reference Level

The defined sound pressure level for calibration is called "Reference level"; 85dB at -20dB signal, or 105dB peak for each main front channel at 0dB, 115dB peak for the LFE channel. This does not mean movie sound is always 105dB, it is just a reference level for calibration. Typical sound pressure levels for a movie played at reference level, or 0dB, can be 70 - 90dB - lower for quiet scenes and louder for heavy action.

The purpose is to ensure playback level is known compared to what was intended when the movie was made.

When your system is properly calibrated, sound will play at reference level when the master volume display on the receiver says "0dB". Many will find this quite loud. It is perfectly valid to choose a different level, that is what the volume control is for, and the calibration also ensures that a -20dB setting is equal to a -20dB setting in another setup.

Often, reference sounds "loud" because the sound is distorted and compressed. This happens if the speakers and the amplifiers are not capable of delivering sufficient sound pressure level, and thus will distort the sound. And this will be the case for most ordinary hifi-style speakers - they simply do not have enough sound pressure capacity.

Room acoustics will also affect perceived loudness. A room with insufficient damping will sound louder, because it actually is, with the same volume setting. Smaller rooms also tend to be louder, because they have more early reflections.

To be able to reproduce sound at reference level is often used as a requirement for theater sound. But at home you are in charge of the volume, and a good system will sound better also at lower loudness levels - dialogue will still be crisp and clear and intelligible, and you will have the sense of powerful bass even if the house is not shaking apart.

Typical movie playback at reference sound pressure levels:

Typical movie playback at reference sound pressure levels

Sound exposure (dB SPL-C) Max peak (dB SPL-Z peak)
Dialogue scene 65dB 85dB
Quiet scene < 55dB --
Massive action scene with cannons 90dB 120dB (LFE) 110dB (>120Hz)
Theoretical max sound pressure levels

Max SPL (dB RMS) Max peak (dB SPL peak)
All channels 0dB, diffuse sum 117dB
All front channels L/C/R 0dB no LFE, in-phase sum 114dB
All channels 0dB, in-phase sum (possible at low frequencies only) 125dB 128dB

Sound pressure levels logged from listening position, scene from the movie Master & Commander. Red line is peak level - this defines capacity requirements, black line is dB(Z) - this is the perceived loudness


The subwoofers are responsible for reproduction of the lowest frequencies, the low sound you can barely hear but feel. In movies these low tones are important for the experience as it is the lowest frequencies that gives realism and physical dimension to the scenes playing.

In most home theater installations subwoofers are not properly dimensioned, and can not give a realistic reproduction of low frequency effects, due to lack of extension and insufficient sound pressure level. Too small subwoofers can not reach down below 20Hz with enough impact to give a real physical effect.

As a minimum extension should reach down to below 20Hz flat, and level should be matched to your listening level.

If level is specified as reference 0dB, that equals 125dB capacity for subwoofers when low frequencies are rerouted from front and surround channels. This is not easy to achieve, and will require several large cabinets. However, if one can get by with a little less, it is much easier to meet the requirement. LFE alone is only 115dB at 0dB, and it is rarely likely that all other channels have full 0db content at the lowest frequencies - in fact, this is impossible if there are other sounds at higher frequencies playing simultaneously.

The general rule is, it is not possible to get too much subwoofer capacity, and the more the better - it will sound cleaner, more dynamic, more realistic.

Sound quality

No distortion or bad sounds, voices and instruments appear separated and clear, everything from the very deep bass up to the highest treble is reproduced, and transients and impulses sound powerful and clean.

This is achieved when you have a smooth frequency response, no early reflections, controlled decay, no audible distortion from amplifiers or speakers.

Contrary to what the audiophile "high-end" myths will try to tell you, achieving this does not require magic, it is all about science and engineering. You do it by speaker selection, room acoustics, calibration.

If you follow the advice given in this guide, you will end up with a system with very good sound quality.

Sound character

Does it sound smooth and nice, or is it open and direct, perhaps leaning towards more hard and dynamic. But can you have it all - smooth and nice - and open and dynamic, at the same time.

Depends. Most traditional hi-fi speakers sound more smooth and nice than accurate and realistic. Many professional-style speakers with horn loaded high-frequency drivers can give you better dynamics, but some times at the cost of a more hard and forward sound character. But the best speakers can give you more of everything - smooth and dynamic at the same time. Key parameters are capacity and controlled directivity.

This character of sound will be determined by the speakers, but you will also be able to make adjustments with calibration and set-up.

If you are on a budget, some compromise may be necessary, but certainly it is possible to have it all, and even better. A system with full dynamic capacity and high resolution may at first sound unfamiliar, because it does not quite sound like "speakers" anymore, and that is exactly the point - it sounds realistic.

If you follow the guidelines from this article, you will end up with open, realistic and dynamic sound, more forward than laid-back and nice. A sound character I find very addictive for both movies and music.


Requirements for home theater and media room sound reproduction
# Requirement Specification (Suggested alternatives) How to achieve
1 How loud Reference Speakers and amplifiers must meet SPL requirement
2 Speaker configuration 7.1 / 6.1 / 5.1 / 4.1 / 2.1 , x.x.4 / x.x.2 Add speakers according to chosen configuration
3 Clean sound Yes? Fulfilled when #1 is satisfied
4 Subwoofers Max SPL +10dB / Reference / -10dB, extension <20Hz Add subwoofers with sufficient capacity
5 Sound coverage Similar sound across all seats Speakers with linear response across whole seating area

Next: Equipment ->