Best Room Shape For Acoustics and Home Recording

Deciding which room to use for home studio recording can be a tricky matter. We want our choice to have the best acoustics so as to produce the best recording result. Unfortunately, there are many factors that played into how a room design can affect the way signals are recorded. We will start with the standard answer and move on to consider non ideal situations.

The best room shape is a rectangular shaped room. Angled walls make the sound waves travel in unexpectedly ways and require more technical knowledge to direct the audio waves correctly. A rectangle room is straight forward to set up and is best for first timers.

In the rest of the article, you will learn:

  • what is the ideal room dimensions for acoustics
  • how to treat a round room
 

Golden ratio for room acoustics – the magic number for perfect sound?

In audio research, there is something called the golden ratio for acoustics, which is the recommended ideal room dimensions for acoustics . The smaller the rooms, the more importance are the dimensions to the audio quality.

This golden ratio for acoustics is stated below, with a preferred height of 8 ft.

1 (height): 1.6 (width): 2.33(length)

If your room has the preferred height of 8 ft, the rest of the ratio is as below

8 (height): 12.8 (width): 18:64 (length)

However, in the event that the room does not have the perfect golden ratio, the following ratios are also acceptable

1.0:1.9:1.4
1.00:1.9:1.3
1.00:1.5:2.1
1.00:1.5:2.2
1.00:1.2:1.5
1.00:1.4:2.1

The worse case scenario is when you have a room with 2 or even 3 identical dimensions. In such cases, the resonances between the walls are magnified, leading to inaccuracy in the audio quality, especially in the lower range.

Finally, do note that these are general guidelines. You need not follow them exactly but can used them in your audio room design.

 

Acoustics of a round room

If you have a circular instead of a rectangle room, the acoustics will become much more complex due to:

  • Standing waves problems are magnified
  • Low frequencies tend to swirl around too much
  • Mid to high frequencies become less focused
  • Difficult to treat one without causing more problems for the other

Some of the issues highlighted above might sound foreign to you if you are not audio engineering. For example, let’s take the case of the standing waves.

Editor notes: Standing waves is a result of low frequency pressure not fitting into the size of your room and will usually resulted in a louder than average audio sound.

The sound energy that cannot fit into the room needs to go somewhere. When your room is rectangle, we can try to make use of the length to reduce the ‘lack of space’ problem. When your room is rounded, every dimension is the same. This means there isn’t any spot in a round room that can remedy the standing wave problem.

And this is just one particular problem. Mix this with the rest of the problems I have listed above and you can see why a round room is super hard to work with in terms of acoustic treatments.

How to treat acoustics for a round room

Here are a few simple tricks that you can consider:

  • Room within a room. You can set up a recording or vocal booth within that room. This will make it 10 times easier to have proper acoustics without pulling your hair out
  • Turn your round room into a five corner polygon using wall panels or acoustic foam walls. A five corner room using the benefit of (i) no parallel walls, (ii) easy to build and (iii) no sharp corners. You will lose some space but the treatment of your acoustics will be simplified relative to a round room.
  • 2D Diffusor: In round rooms, the center of the room is where all the problem collide. By having some 2D sound diffusor in this spot, the excessive audio can be absorbed, which will prevent all the weird effects you will be getting.
 

Bigger vs smaller room for acoustics

Size also plays an important role in affecting the acoustics for the room.

The general rule of thumb is that bigger is always better than smaller.

For a small room, there are numerous problems including:

  • Standing waves: the standing waves problems stated above becomes much more severe as there is a minimal space needed for the audio sound to travel. So what you get are pressure areas whereby the sounds become uneven.
  • Echoes: Sounds will get reflected all over the place. The smaller the room, the more echoes you will hear ie. your bathroom. To kill off these, use sound absorbing foams on the walls, ceiling and floors.

For bigger rooms, there are enough space for a rooms’ modes to be evenly spaced out. In general, a 40 ft room will be sufficiently large to allow natural reverbs to happen. Anything smaller and you will need to start playing with acoustic treatments.

 

Conclusion

For a beginner, a rectangular large room is the best room shape to work with, in terms of having good acoustics.

If you are working with any other shapes, you will run into more severe problems of standing waves, echoes and other audio distortion effects. It is possible to treat them but you need to spend both money and time.

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