This is just to give a quick crash course in recording studio acoustics, I will be discussing basic Recording Studio Acoustics on this page.

Sound can be calculated very precisely, we know the speed of sound, we can then calculate which frequencies that can fit between two objects, you then have sound nodes, or standing waves.

We can then tell which frequencies will cause the biggest problems within a certain size room. As in, which frequencies will stand out and which frequencies will disappear.

If you have the luxury of starting from scratch, you can then apply these acoustic principles in your recording studio acoustic design so that there are either no obvious peaks and drops or that they can be controlled once the recording studio is built. But at least you will be prepared and know what you will have to overcome.

If you have an existing recording studio, so have to either remedy the acoustics you already have or drastically redesign your recording studio. All depending on the space you are working with, you may find that by just decreasing one wall by 1cm will save your studio and bring peace to your life.

Example

We recently designed and built a studio for a client, where the space was limited and sound proofing was a big concern, when the recording studio design was complete, the tolerances I gave to our construction team was only negative 5mm. What this means is the control room and live room dimensions could only be 5mm bigger than specified they could not be 5mm smaller.

(These tolerances are a tall order for the general builder, which is why we have our own construction team, all they build are our recording studios)

When putting up the 'last but one' layer of plaster board in the studio live room, it was evident that the acoustics were going to be impressive, but there was a nasty spring to the reverberation in the room. However once the final layer of plaster board (12.5mm) had been applied, the reverberation in the live room not only made me smile, but made my client extremely happy, and the nasty spring had disappeared.

The long and short of it is, Recording Studio Acoustics our an exact science, which can be mastered if you have a good understanding and time to calculate all possible varables. Basically a hole heap of maths.

Our calculations are done on our own massive excel document, with over 15 internlinked worksheets and 2000 rows and 100 columns in each worksheet, just to calculate and reference recording studio acoustic reponses and sound proofing effects within a single room.

Parallel Walls

You may of come across the phrase or saying “Avoid Parallel walls when it comes to Recording Studio Acoustics”, this only really applies when the space has so many bad sound nodes / standing waves, that all you can do is try and cover them up by creating even more!

When building a studio the first thing you hear from associate studio owners is "make sure you don't have parrellel walls'. Now don't get us wrong, none Parrallel walls are useful in a studio and can really benifit the acoustics if you can exactly calculate what they will do. However most studio builders put none parrallel wall in there design as a "well everyone else is doing it" type of approach.

When we do our designs, we imbrase parrallel walls and none parrallel walls. Parallel walls actually bring certainty and control; you know exactly what you will have when your reocridng studio is built.

This is the reason; say your control room is 4m in length and 4m in width and 3m in height. If all those walls are parallel, the sound nodes / standing waves will be the same. If all the walls are none parallel / slopping in one way or the other, straight away the distance between each area is different at different points between each apposing surface. This basically means instead of you dealing with say 10 sound nodes /standing waves between each surface, you may end up tripling the number of sound nodes. The only thing you have done, is decreased the level of each sound node. But you end up with a messy sounding room, which is allot harder to treat.

Now this is not to say that you should work in a box, as you may well know, most top end studios have lots of apparent angled walls. The only difference is that these angled walls are either exactly calculated or the wall is actually fake and there is a parallel wall behind the visable wall, and the visable wall is fabric.

There are some magic angles that work extremely well when design the acoustics in your recording studio. However these are only used, if you have enough space.

Brightening or dulling the acoustics in your Recording Studio

Most control rooms normally have a reverberation time of around 0.9 seconds to 1.2 seconds max and have a live end at the back of the room and a dead end or controlled end at the front where mixing area is.

(The dead area is the controlled area were you can hear all aspects of the sound, with out much influence of additional reverberation, this area is not dead as this will cause ear strain, it is meant to be around 0.25 to 0.5 second)

(The live area is to imitate the living room environment, which saves time when you A/B music)

Live rooms normally have a reverberation time of 1.2 seconds to 1.5 seconds maximum, which additional means of controlling and reducing and increasing the reverberation time.

It doesn’t take rocket science to know that soft materials absorb sound and hard frequencies reflect sound. Also that the weight of the absorbent material determines the frequencies it is able to absorb. The heavier and deeper the soft material the more low frequencies it is able to absorb, the same would be for reflective materials, the lighter the hard material, will result in only higher frequencies being reflected and lower frequencies passing straight through (just like it wasn’t there!).

So you can start to see that you can start to control the way sound behaves within a given space and you can drastically affect it with massive.

It is also worth mentioning that having curved reflected materials like half circles is always better for reflecting sound, as it disperses sound and doesn’t focus the sound.

It seems to be the latest craze to invest in bass traps in project studios; you just know you need them, without really knowing why! Corners of any room have the potential of acting like bass amplifiers, which basically means they will amplify any bass that hits them and send them out slightly louder in proportion to the overall size of the corner of the room. Kind of like using an old none powered megaphone, the sound is amplified as it exits, just like the corner of the room, so if it is able to find its way into the corner of the room, and there is a hard reflective surface to reflect back off, then it will head back the other way slightly louder!

Corners of rooms can be dealt with by either blocking in the corners, so the room starts to resemble a hexagon. Or simply add absorption to the corner of the room, you will of course have heard of bass traps. Although it has to be said, that most of these products sold are over prices and are designed to take advantage of the project studio owner, but that is another rant of mine. Please note I am not saying that the products these companies sell don’t work, more that you could do the same if not better for a quarter the price while still having a visually appealing studio.

Please note, I am not saying you can fix all your problems by trying to absorb all the frequencies that cause you problems, as this will only cover up frequencies to a point, and your ears will be able to tell what is going on as you walk around you room. I am saying that you can fix issues with some slight structural modifications, or even better fix them before you build your recording studio.

Well that’s it for now, if you want to learn more, why not visit our main website at www.technicaladvice.co.uk there are loads of free resources available.

You may have gathered that we our acoustics consultants, and spend all of my time either designing recording studios or building recording studios for clients and advising people just like you.

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Recording Studio Acoustics, Added on the 09-07-09, updated on the 10/06/11