Studio design basics

Ok, let's see if I've got the Studio Design basics right. One should usually: - Have/make a concrete floor (or similar heavy mass) - Build double walls, decoupled, with only two leafs - Have no parallel walls (inner walls that is) (edit: See post 2) - Soffit/flush-mount the speakers - Have a room of no less than 70cubiq meters (recording-room) - Make bass-traps in most corners (4 and 12 corners) - Put absorption on reflection-points for speaker-to-listeningposition. But ideally there should me no such points. - Put absorption on reflection-points for recording-spot-to-mic. - Make Helmholtz resonators to add absorption for low frequencies and reflecting/diffusing high frequencies. These should be tuned for the room, and will make the rooms reflections/absorption more flat across the whole spectrum. Edit: Slot walls (see thread) - Ceiling should normally have high absorption-factor. - Build necessary ventilation (but I don't know how..) So, is this basically right? Any important things I've forgotten?

So, is this basically right?

That's pretty much it! The only two I would argue with, are:

- Have no parallel walls (inner walls that is)

You can have parallel walls if you want, as long as they are treated correctly.

Make Helmholtz resonators to add absorption for low frequencies

I would not try to do that, except as a last resort if nothing else worked. I would go with ordinary broadband absorption first, maybe diffusers if the room is big enough, general slot walls, and then measure with REW. Apart from that., I'd more or less agree with all the other points. - Stuart -

Thanks Stuart!

Soundman2020 wrote:

- Have no parallel walls (inner walls that is)

You can have parallel walls if you want, as long as they are treated correctly.

Thanks! That's important knowledge to me. I have to find out more about that. Do you have any links/ info to understand this better?

Make Helmholtz resonators to add absorption for low frequencies

I would not try to do that, except as a last resort if nothing else worked. I would go with ordinary broadband absorption first, maybe diffusers if the room is big enough, general slot walls, and then measure with REW.

Ok, thanks a lot, as this would take me a lot of time design-wise (and to understand). Slot wall: Is that just panels mounted for uneven reflections, or is broadband-absorber with panels spread in front?

Do you have any links/ info to understand this better?

I'd suggest two books: "Master Handbook of Acoustics" by F. Alton Everest (that's sort of the Bible for acoustics), and "Home Recording Studio: Build it Like the Pros", by Rod Gervais. And also read John Sayers work @ http://johnlsayers.com/Recmanual/index.htm

Slot wall: Is that just panels mounted for uneven reflections, or is broadband-absorber with panels spread in front?

It is actually a broadband resonator / diffuser / reflector / absorber! It consists of a number of wooden slats with gaps between them (the "slots") and a sealed cavity behind them, with absorption. Each slot is a Helmholtz resonator, and they are all tuned to different frequencies within the range that you need to deal with. The depth of the cavity changes from one end to to the other, which makes the Q for each slot broader, so it affects a range of frequencies. The slates themselves also reflect high frequencies back into the room, the edge of gaps act as diffusers to a certain extent, and at frequencies well below the tuned range, the entire unit absorbs. So it does a lot of things all at once. - Stuart -

Soundman2020 wrote:

"Home Recording Studio: Build it Like the Pros"

Thanks! Ordered

Slot wall: Is that just panels mounted for uneven reflections, or is broadband-absorber with panels spread in front?

It is actually a broadband resonator / diffuser / reflector / absorber! It consists of a number of wooden slats with gaps between them (the "slots") and a sealed cavity behind them, with absorption. Each slot is a Helmholtz resonator, and they are all tuned to different frequencies within the range that you need to deal with. The depth of the cavity changes from one end to to the other, which makes the Q for each slot broader, so it affects a range of frequencies. The slates themselves also reflect high frequencies back into the room, the edge of gaps act as diffusers to a certain extent, and at frequencies well below the tuned range, the entire unit absorbs. So it does a lot of things all at once.

lol That sound just like what I termed Helmholtz resonators in the first post. What's the difference? Anyway, some of these what was I had in mind :)

By definition, a Helmholtz resonator is a single-frequency device. It has a reasonably high Q, and is aimed at treating that one specific frequency, usually a standing wave, and therefore must be placed at the pressure peak of that wave. While a slot wall is based on the principle of Helmholtz resonators, in that it involves slugs of air vibrating in the thin neck of the device over a sealed cavity, it is not designed to treat a specific frequency. Rather, it is designed to treat a broad range of frequencies all at once. The Q is much broader and a bit flatter than for a pure Helmholtz resonator, and so is the coverage: it cannot be placed at the pressure peak for any specific frequency, since it is a wall. Indeed, some acousticians say that it should not even be thought of a bunch of individual resonators that act individually on specific separate frequencies, but rather as an entire surface that treats all frequencies within the bandwidth, to a greater or lesser degree. But apart from being a resonant device, it is also diffusive (which a single point Helmholtz resonator is not), since it has a series of wells and solid surfaces that provide edge diffraction, reflection at different angels depending on angle of incidence, phase changes, etc. In addition, since it consists mostly of hard flat rigid surfaces, it is also a major reflector, and can be angled in various ways to benefit different aspects of the room response. Finally, also unlike a classic single-point Helmholtz resonator, at frequencies considerably below the tuned range, it simply acts as pure un-tuned broadband absorption. So while it is based on the same principle as a classic Helmholtz resonator, it does not perform in the same way. Another example of an acoustic device that is based on the same principle as a Helmholtz resonator but performs differently, is. perforated panel. - Stuart -

Brilliant! Thanks Stuart!

it is always preferable to situate a recording studio ... in an area where it could easily be accessed by possible clients and patrons.

Damn! Now why didn't any of us think of that before? Wow! What amazing words of wisdom! This has the potential to change the entire recording industry!!!! Imagine that! Commercial studios should actually be built where clients can get to them! What an amazing, incredible new development! And this nugget of wisdom comes from a spammer that claims to own a "mobile" studio that is "soundproof" and acoustics that are "not nasty"? :) :poke: :ahh: :shock: - Stuart - EDITED TO ADD: The above comment was a reply to a rather surprising and pretty dumb post by a spammer trying to rent out his silly little mobile "studio" in a van. The spammer was later banned, for obvious reasons, and all his posts were removed, but my reply is still here, without the original context of his post. So please don't take this as being a comment on anything G-Sun said! G-Sun is the good guy here: his thread was just hijacked by the spammer.