John Sayers' Recording Studio Design Forum

As John details here...

http://www.johnlsayers.com/HR/index1.htm

Im wondering , if positioned correctly, these would take care of early reflections from each side wall in your room? I like the idea of combining some absorption with some redirection of mids and highs towards the rear of the room. I like slats, gotta find a way to make a RFZ out of them (forgetting the ceiling for the moment) .Seems less risky this way than building integrated angled walls, if it will work.....thanks as always.

ok, I just noticed that it does say it "breaks up side wall reflections"....I guess Im just looking for confirmation that it does this as adequately for a RFZ as mounting a large thick slab of rockwool on the side wall.

Dude, do you know where you are? If John Sayers speaks acoustics...you can trust it.

A slab of rockwool or a vented wall system that adds absorption with a small amount of diffusion with high frequency reflection...actually it isn't a reflection free zone, but it is integral to it...use it, you are safe with that.

I personally do not like the saw tooth, but having never designed or built one, I may not be able to give much help on that. My notions are all based on what a ray will do.

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Brien Holcombe
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Sound: You can't stop it, you can only try to contain it.

Oh sure, I have been researching for months for my build. I trust everything I read from him, absolutely. Im just trying to fully understand everything before I attempt to drive the first nail.

For example., John says in the plans he has kept a straight face across the unit, but if you want to follow the angled slats thats fine, this is what I plan to do as I want to use it as a side absorber/re director of mids/highs. Obviously if you use these things in the first reflection points on the walls between you and your speakers, then you MUST have the slats angled right? If you straight face it , obviously it will work but you will get reflections straight at your head from the slats.

Hell, it would be easier just to make a standard trap out of 703 for this purpose, but Johns units look a hell of alot more elegant. Also, I have been in studios following the principle of redirecting mids and highs towards the back where they meet a combination of absorbtion and diffusion on the rear wall. I really liked the effect.

Exactly. You need to ray-trace to make sure that the angles are correct, and that you will indeed create an RFZ.

They also work on an entirely different principle than a simple piece of 703!

Is your room big enough for that? Diffusion can only be used successfully in rooms of a certain size or larger. (Of course, that doesn't stop may ignorant DIY builders from putting in skylines or other QRDs just a walls that are just couple of feet away, and thinking that they did something amazing.... )

Yes.

Actually, slot walls are NOT absorption plus re-direction: That's not what they are for: If all you want is "absorption and redirection", then make sure you leave very large gaps between the slats, to ensure that they are tuned way to low to be efficient or useful for their real purpose.

You seem to be missing the entire design concept: As the text says, one of the things a slot wall does is to BREAK UP side wall reflections: Not the wording: it doesn't say that it "redirects reflections to create an RFZ design. It says that it breaks up reflections. In other words, it creates diffusion (in addition to the other things that it does). Breaking up reflections and creating an RFZ are two totally different and unrelated things. RFZ is a design concept for the entire room. which may or may not include "breaking yo reflections". And devices that "break up reflections" can be used in rooms that are or are not base on RFZ concepts. Two different things.

And no, "mounting a large thick slab of rockwool on the side wall" does not create an RFZ design either: You can have an RFZ design where there is no rockwool at all on the walls, and you can also have a design that is NOT based on RFZ but that has a mountain of rockwool on the walls. Once again, two very different things. Rockwool can be part of an RFZ design, but isn't required to do so.


- Stuart -

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I want this studio to amaze people. "That'll do" doesn't amaze people.

Yes,Ok then...how about it solves the problem of early reflections from the side wall when combined with other elements that make up a RFZ?

Well, it will do that, and it will do a whole bunch of other things, too!

- Stuart -

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I want this studio to amaze people. "That'll do" doesn't amaze people.

Ok thanks Stuart. My rationale is that almost all rooms are going to have a small frequency range that you just can't hit with the broadband absorption that you have installed. So it would seem to me that you can kill two birds with one stone by solving the early reflection problem number one, and two you can tune the slat absorber to this band of frequencies. And number three is you can keep the room more live this way. I will have about 11 or 12 ft to the back wall so diffusion should be ok. The rear wall itself will also be a 12inch trap to go along with the diffusion. One fake or screened off wall at the back is very easy to do if you have the space.