ESSENTIAL INSTALL: Demo Room Acoustics

How important are demo room acoustics? Crucial, argues Chris Adair, acoustics expert and owner of CEDIA member company, Adair Acoustic. In this issue of Essential Install, Chris explains the significance of a good acoustic system and the things that integrators need to consider when designing a state-of-the-art demo room. 

Everyone building a new demo suite is aware that the acoustics of the room will have a huge bearing on the performance. 

The problem is that to design an acoustically sound room in a very small space requires a specific set of priorities. Traditionally, the only professionals working in this area have been recording studio designers, and they are looking for very different things from the space. 

A demo room needs to look appealing, so looks often win over performance, meaning that the room is constructed on a wing and a prayer that the acoustics will turn out fine. They frequently don’t!

My personal experience of demo rooms is that they are the key selling tools, demonstrating the acoustic experience. People can hear the difference, and if you make a great sound, they will take away that great experience.

You can show people a light switch, or a picture of a light switch, and they’re happy to confirm the purchase with no need for a demonstration. Show them a speaker though, and they’re more likely to think about how big it is and how it'll look at home, so a demo is essential to promote its acoustic importance.

In a great sounding demo room, you are already off on the right foot. Play a great piece of music and very quickly, your client will be hearing your system sounding at its best and will be less concerned about how those speakers look.

However, if you play that same music in a terrible acoustic environment, then nothing will sound great, and those ugly speakers will stay ugly. Sure, you can compare one piece of hi-fi with another and reveal huge differences, but there is no way you’ll really wow the client with a great sound that they’ll carry with them in their head all the way home…

When you are designing a demo room, there are a few things you should consider: 

  1. Bigger is better! Don’t make two small rooms, make one big one. 
  2. Avoid low ceilings: you need that ceiling height for a variety of reasons.  
  3. Don't put the listening position against the rear wall. Just watch what people do in rooms like that: they perch on the edge of the sofa leaning forwards to get their head away from the wall, so they can “hear” the system. 
  4. Acoustics likes variety. Perfectly flat parallel wall are the pits. (Flutter, echoes, etc.) 
  5. Side wall reflections. I used to think that the shoebox shape was best as you listen down the length of the room, but that’s a basic mistake. Being so close to the sidewalls means that the first reflections really smear the sound, so it’s usually better to make your demo room wider and sit closer to the speakers. 
  6. Bass. This is a really complex subject, but people are sensitive to bass. You must balance the bass 80-300Hz especially, and to do it naturally, means the walls of your rooms can’t be too rigid so avoid a small cubic concrete box. But that’s the favourite starting point for a basement home cinema, isn’t it?! Time to call in a specialist acoustician!