You can find out how much airspace do 6″x9″ speakers need by determining the enclosure dimensions, multiple them with each other (HxWxD), and then divide that number by “1728”.
Airspace is the volume of the inside of a speaker enclosure. If you want your speaker units to produce the sound for which they are originally designed, you need to ensure that their enclosure has sufficient airspace. All the high-range frequencies and low-end reverbs make better sound when they have the right airspace to swank from.
But how to know how much airspace a speaker needs, particularly if it doesn’t have uniform dimensions (e.g. 6”x9” units)?
If it is not given in the user manual, you have to calculate it on your own. Here, we will discuss an easy hack to find out how much airspace do your 6”x9” speakers need.
Determine the enclosure dimensions and multiple them with each other
We are assuming that you need a strappy enclosure for your 6”x9” speakers. Going by this assumption, the height of the enclosure will be 8.25 inches; the width will be 12 inches with a depth of 7 inches. Multiply these numbers with each other.
8.25 x 12 x 7 = 693
Divide the obtained number with “1728”
Now, divide the obtained number with “1728”, the resultant number will be the value of the airspace in cubic feet.
693/1728 = 0.40 cu-ft
With this value in your hand, you can commission a beefy custom-made enclosure for your 6”x9” speaker set. You can also tweak the value (e.g. increase it a bit) to adjust airspace in line with your requirements.
For instance, if you have powerful speakers that have greater volume displacement requirements, you should increase the airspace value by 20% for better sound results.
So, 6”x9” speakers with a high RMS value (powerful output) will need airspace of around 0.20 cubic feet. For further volume displacement, increase the airspace volume by 20%.