Stone Diffusers?

[DaleNixon]

I was thinking of making some stone panels to act as diffusers for my live room and I was wondering if anyone had any experience with stone and it's effectiveness?

thanks!

[JonCraig]

when i was at school, they built two more small, 2 room studios, and used cinder blocks sticking out different amounts from the wall to act like a diffuser. it sounded like total ass.

hope that helps!

--jon

[Glenn Kuras]

yea you have to be careful with diffusers. It is NOT a random thing, but a lot of math that goes into it. If that was true then companies like RPG would just use some odd shape and call it the day.

Glenn

[Ethan Winer]

Originally Posted by DaleNixon

I was thinking of making some stone panels to act as diffusers for my live room and I was wondering if anyone had any experience with stone and it's effectiveness?

As was already explained, real diffusors are not random. More to the point, just as important is having enough depth from the front to the rear. So while it might be possible to make a diffusor from stone, you'd need very large pieces!

--Ethan

[Engine Room]

We have "gobos" made of a variety of materials. They are extremely useful for adding 'reflection' and 'absorption' to our drum riser when recording.

I haven't tried stone, but you have given me some food for thought....


Stone isn't very 'diffuse', it seems very reflective...I like the echo of a good cave though!

[DaleNixon]

Perhaps Diffusers are the wrong term then. Just something that would mix up the reflections of straight walls. I'm not operating with a big enough space/budget to be able to afford real diffusers/have the space to give up for them... I was thinking Stone panels floor to ceiling along the back wall of my live room (which is straight) just to break up the straight reflections. I just didn't know if anyone had any experience/suggestions in this situation.

[charles maynes]

Originally Posted by DaleNixon

Perhaps Diffusers are the wrong term then. Just something that would mix up the reflections of straight walls. I'm not operating with a big enough space/budget to be able to afford real diffusers/have the space to give up for them... I was thinking Stone panels floor to ceiling along the back wall of my live room (which is straight) just to break up the straight reflections. I just didn't know if anyone had any experience/suggestions in this situation.

My favorite DIY diffusion was what David Bottrell did at his studio- Put up a lot of book shelves and fill them with books-

You get good reading material for everyone as well as nice sound...


charles maynes

[Glenn Kuras]

Originally Posted by DaleNixon

Perhaps Diffusers are the wrong term then. Just something that would mix up the reflections of straight walls. I'm not operating with a big enough space/budget to be able to afford real diffusers/have the space to give up for them... I was thinking Stone panels floor to ceiling along the back wall of my live room (which is straight) just to break up the straight reflections. I just didn't know if anyone had any experience/suggestions in this situation.

I would think that building a stone wall would not be cheap.. might cost more then buying real diffusers.. Not to mention a REAL PAIN IN THE ARS!

Glenn

[No4PCs]

Originally Posted by DaleNixon

Perhaps Diffusers are the wrong term then. Just something that would mix up the reflections of straight walls. I'm not operating with a big enough space/budget to be able to afford real diffusers/have the space to give up for them... I was thinking Stone panels floor to ceiling along the back wall of my live room (which is straight) just to break up the straight reflections. I just didn't know if anyone had any experience/suggestions in this situation.

I think really cool some stone panels.

[Scott@RealTraps]

Originally Posted by DaleNixon

Perhaps Diffusers are the wrong term then. Just something that would mix up the reflections of straight walls. I'm not operating with a big enough space/budget to be able to afford real diffusers/have the space to give up for them... I was thinking Stone panels floor to ceiling along the back wall of my live room (which is straight) just to break up the straight reflections. I just didn't know if anyone had any experience/suggestions in this situation.

Yes, what you are talking about is "diffusors" of a sort. HOWEVER . . . as has already been pointed out, proper diffusors are not random, and "psuedo" diffusors, especially if used in a small room, can potentially cause as many problems as they solve.

First of all, in most cases, if you have a diffusor closer than about 10 feet or so from your head, you will be hearing the acoustic anomalies (i.e., comb filtering) across the face of the diffusors. This is ESPECIALLY the case with diffusors that are not properly designed, or with random attempts at diffusion. Further, aside from skewing the frequency response (because of the comb filtering), having random/improperly designed "diffusors" at relatively close range behind your listening position can really muck up your imaging (which can also happen with properly designed diffusors if they are too close). So . . . not a good plan, really. Likewise, I don't recommend diffusors for first reflection points on the sides or the ceiling (again, unless you are in a LARGE room, and you are using *properly* designed, non-random, diffusors).

For small rooms, your best solution is going to be broadband absorption. If you're on a tight budget and looking to DIY, get yourself some OC 703 (or equivalent), make some wooden frames (preferably with large holes in the sides), build some panels that are at least 4 to 6 inches thick, and wrap them in acoustically transparent fabric (i.e., you should be able to blow air through the fabric with no resistance). Mount at least four such panels in the corners, and then, if you can't spring for thicker traps on the walls, you can use 1 or 2 inch 703 panels to slap down the high and mid frequency flutter echoes.

I know you are mainly asking for a solution to the high and mid frequency reflections, but you really want to make sure that you have a good amount of absorption across the entire frequency spectrum, otherwise you end up with a dead, muddy sounding room (ALL small rooms *need* bass traps -- it's a reality of physics).

Overall, OC 703 (if you are not familiar, these are rigid fiberglass panels of a 3 lb density) or various other glass or mineral fiber equivalents are essentially the most cost-effective acoustics treatment materials you can get for all around use.

[JonCraig]

Originally Posted by charles maynes

Put up a lot of book shelves and fill them with books-

dave martin, who occasionally gets on this forum, has done just that, and it sounds great!

http://www.javajivestudio.com

--jon

[Scott@RealTraps]

Originally Posted by JonCraig

dave martin, who occasionally gets on this forum, has done just that, and it sounds great!

http://www.javajivestudio.com

--jon

Notice, though, that this is in a tracking room -- and a good sized tracking room at that. He also has absorbers right behind the drums.

In a tracking room, stereo imaging is FAR less critical than in a control room, or in a room that is used for both tracking and monitoring/mixing.

In the above pictured case, he's got what look to be broadband absorbers/gobos behind the drums, which I assume are there in part to offer some low frequency absorption, but also isolate the overheads a fair bit from getting direct reflections from the book cases, which would eliminate or at least minimise the comb filtering problems I mentioned above.

When you are looking at acoustics considerations for live tracking rooms and control rooms, there are different priorities. Imaging and accuracy are incredibly important in a control room, but in a tracking room, where many instruments would be recorded mono, and where having an overall ambiance that is controlled, but musical, stereo imaging, etc. is *much* less of an issue, if it's an issue at all. For example, who's going to worry about stereo imaging in a vocal booth?

Also, when you are considering small room acoustics versus large room acoustics, a lot of things change with regard to what kinds of treatment constitute best practice.

This is not just me saying this. I've got BBC white papers and other research going back quite a few years discussing, among other things, the use of diffusors in small rooms/at close range versus diffusor use in large rooms. And it's also something I've experienced for myself in treating smaller control rooms.

The bookshelf thing *can* work to a certain degree in the right situation, but, in a small room critical listening environment, there are much better solutions -- i.e., broadband absorption.

(That said, I still can't wait to get my hands on one of our new diffusors to try in my studio! I believe I have enough room for them to be of practical use.)

[JonCraig]

Originally Posted by Scott@RealTraps

The bookshelf thing *can* work to a certain degree in the right situation, but, in a small room critical listening environment, there are much better solutions -- i.e., broadband absorption.

agreed. i had bookshelves on the back wall of my home editing/mix room, and when i installed broadband absorption, it made a MUCH bigger difference than the books ;-)

--jon

[RusRant]

I have a large stone wall/fireplace in my main room and it is highly reflective. Not a good diffuser at all. but gives the room a great sound. I would invest in proper diffusers and let that be that. Sounds like you would waste a lot of time and money chasing your tail on this IMO.

[mltamisin]

I don't see why not. It's a highly reflective surface so maybe just do a small wall. Oh, diffusors work fine in my room. I've got a 11' x 19' x 8' tall room. Diffusion on the ceilings, front wall, and entire back wall and it sounds killer. I had broadband absorbers where all the diffusors used to be and it was far too dead. Diffusors are just as important as absorbers....even in smaller rooms. As long as you're not mixing in your dorm room or bathroom or something. If you're about 4' away from the diffusor then you'll benefit from it. All you have to do to prove it is stand 2'-3' in front of one and sing into it, then move over to a bare wall and do the same. I'll bet the diffused wall will sound much better.