JimmyS1969
MOODerator
Well, it is better than nothing. Are you in US? Harbor Freight has cheap moving blankets.
Small Room Acoustics
- Thread starter jhbrandt
- Start date
Robert27191
New member
No, am in the UK I'm afraid!
I posted a portion (the speaker placement portion) on another site. JH I can send you a link if you would like (I attributed the quote to you and linked to your website) and I can remove it if you would like.
I think it's great information and it fit perfectly with a topic that had come up on another site. Just let me know if you would like me to take it down and send you a link.
I think it's great information and it fit perfectly with a topic that had come up on another site. Just let me know if you would like me to take it down and send you a link.
jhbrandt
Acoustic Design
Correct. Actually, as little as an inch or two can make substantial difference if your partitions are very dense, i.e.; brick or concrete.
.375 times the distance from front to back IS a preferred mixing position. This is due to the fact that, if sitting @ 3/8 of the length of the room, you will not be sitting in a dip or peak of the length axial mode or it's harmonics... it is an odd multiple of the room length that will work like this. Similarly 3/7 of the room also works to some degree, but the 'sweet spot' will be smaller as this one puts the mixer/listener closer to the center of the room, which will ALWAYS be a bad spot for LF accuracy. - Another reason why we don't usually face the long wall.
Yes, All of these things can work together to make a better recording. I don't want to throw out the baby with the bath water.. it's just that advertising that tries to sell something by saying it is the 'solution' to recording.. and you DON'T need acoustic treatment, and other associated BS, that bothers me. Yes, these things can help.. They all have to help somewhat or they'd be getting returns and going out of business, but my objection to these tiny things is that they are NOT used, nor are they necessary in a proper studio.. a treated studio. If you are a mobile recordist, you may find them invaluable... coupled with moving blankets and the sort. - But if you have a home studio & your budget is 300 to 500 dollars, why not build some real good panels? Something that will really get you the sound you want.
+1
NO PROBLEMO. I post here to help people.. and if it goes viral... that's fine with me. I know it's probably a drop in the bucket compared to exponential propagation of the myths that continue to run..
- And thanks for linking it to my site. I'm just trying to shine a light... The batteries in this old flashlight... I hope they hold.. Cheers,
John
ashcat_lt
Well-known member
That's what I've always heard. Doesn't ask the question I asked though.
I've got my listening position right around there, but that puts my speakers about three feet from the front wall. They make a triangle with my head about 4 feet on a side. Would I be better off moving my speakers all the way back to the wall even if that puts them like 8 feet apart?
Jens Eklund
New member
It appears that as usual when you post something that goes against the "known" thing no one pays attention.
Oh well, I found it helpful. Thanks for the post
Oh well, I found it helpful. Thanks for the post
NO PROBLEMO. I post here to help people.. and if it goes viral... that's fine with me. I know it's probably a drop in the bucket compared to exponential propagation of the myths that continue to run..
Cheers,
John
I was talking with some other guys about room treatment and something they brought up (figured I'd try to fact check here). Is that for things like bass traps that will be 6 - 8" deep, the rule would be the thicker it goes the less dense the material you want to use. IE for bass traps the pink fluffy insulation would be better than say rockwool.
I said I thought that rockwool would be better for bass traps, this was their reply.
Just thought I'd get your opinion. I can post more (with sources) if needed.
I said I thought that rockwool would be better for bass traps, this was their reply.
Just thought I'd get your opinion. I can post more (with sources) if needed.
Jens Eklund
New member
That is correct (although Rockwool per se is not ruled out since there are different types of Rockwool, and some works very well depending on depth). It is a stubborn misconception that very dense wool is best suited for thick velocity based absorbers. The figure of interest for wool used as velocity based absorbers; is the “Gas Flow Resistivity”, and not primarily the density. Although there are loose relations between density and GFR, it is not uncommon for two different types of wool featuring the same density, to have very different GFR values. And yes; for thicker panels, you want to use a lower GFR: Multi-layer Absorber Calculator
jhbrandt
Acoustic Design
ashcat_lt
Well-known member
That doesn't answer my question either. Thanks though.
Edit - Let me restate, though I feel like I was pretty clear earlier. I'm sitting at 38% right now, with might speakers at nearfield distances from my head. If I move them to the front wall as suggested above, I end up at more like midfield distance and the speakers will be a lot closer to the side walls and there's a lot more of those side walls that will need treatment to create an RFZ. Will it actually be better if I do move the speakers to the front wall?
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mjbphotos
Moderator
Not understanding that Calculator that Jens linked (got to be an Acoustic Engineer, I guess), would an 8" trap made with the standard pink loose fiberglass (same stuff you put as an attic blanket) be more or less absorbant than a 4" trap made with typical rockwool (OC 703, for example)?
jhbrandt
Acoustic Design
Only testing will tell. But like you said, you'll need side reflection point treatment.
Do what works best for you... even when we have other speakers next to the boundary or flushed, there are always the 'nearfields' that are out in the room... It's something that you 'deal with'. If those are your only speakers, you may be best off where you are currently.
I know many engineers that deal with SBIR and produce excellent mixes. It's a matter of tuning your brain rather than tuning the room. But if you are doing this professionally and want to 'get there' faster, treatment will more than pay for itself in short order.
Test your listening position and the speaker positions.. find the place where everything gels. There are many things that interact in a room and no two rooms are alike.
Cheers,
John
jhbrandt
Acoustic Design
Attachments
ashcat_lt
Well-known member
Thanks.
It actually sounds pretty good as is, and my half-assed tests look pretty good, too. It's not exactly a small room, partly open to the rest of the house, and the bass really just blows through the walls (and floor, and I suspect ceiling) so it sort of acts like a much bigger space. That said, treatment is on the horizon, and this info about the pink stuff is pretty encouraging since it is much easier to source and afford than 703 and equivalents. Now if it wasn't 20 below so I could get out to the garage for some construction...
It actually sounds pretty good as is, and my half-assed tests look pretty good, too. It's not exactly a small room, partly open to the rest of the house, and the bass really just blows through the walls (and floor, and I suspect ceiling) so it sort of acts like a much bigger space. That said, treatment is on the horizon, and this info about the pink stuff is pretty encouraging since it is much easier to source and afford than 703 and equivalents. Now if it wasn't 20 below so I could get out to the garage for some construction...
Thanks John and guys for the thread. I'm totally blind, and most of the sites I've been visiting to get a grip on room treatment uses graphs and images that mean nothing to a blind guy. Throw that on top of a ton of technical specs that I really don't understand and you end up with one confused puppy. However, this thread actually makes some sense to me. I'm just getting serious about my room and listening environment, so I have several questions. Before I go too much farther then what I have here, I'm wondering ... Should I start a thread independent of this one and dedicated to my ongoing build? Last thing I want to do is get off topic or high jack a thread.
With that said, I would like to address something brought up in this thread. Using the 38% (or .375%) rule for listening position let me make sure I'm correct before starting to talk about treatment. The room I'm in is 14' 7/8" x 11' 2-1/4" and totally untreated at this time. So let's call it, for math's sake, 169"x134". So I should set up facing the 11' wall and .375% out in the room. 169*.375=63.375 or roughly 5'4-3/4" - am I correct so far?
So sitting behind my desk at a comfortable reach, it is 3' 9" (45") for my ears to the back edge of the desk, which leaves 18" between my desk and the wall. Ok, I need to be set up where it is a equal triangle from my speakers side to side and distance to the center of my head. If that is correct then my speakers need to be 45" apart, not wanting to take up desk space I'll want to place them on stand just behind my desk. They are JBL LSR305, which are 9.88" deep, so that leaves just over 8" between the back of the speaker and the wall. So is that too close to the wall? Do I need to have them over the desk? Maybe on short stands, or build a stand where the platform hangs over the desk?
Let me get this in my head before going any farther.
With that said, I would like to address something brought up in this thread. Using the 38% (or .375%) rule for listening position let me make sure I'm correct before starting to talk about treatment. The room I'm in is 14' 7/8" x 11' 2-1/4" and totally untreated at this time. So let's call it, for math's sake, 169"x134". So I should set up facing the 11' wall and .375% out in the room. 169*.375=63.375 or roughly 5'4-3/4" - am I correct so far?
So sitting behind my desk at a comfortable reach, it is 3' 9" (45") for my ears to the back edge of the desk, which leaves 18" between my desk and the wall. Ok, I need to be set up where it is a equal triangle from my speakers side to side and distance to the center of my head. If that is correct then my speakers need to be 45" apart, not wanting to take up desk space I'll want to place them on stand just behind my desk. They are JBL LSR305, which are 9.88" deep, so that leaves just over 8" between the back of the speaker and the wall. So is that too close to the wall? Do I need to have them over the desk? Maybe on short stands, or build a stand where the platform hangs over the desk?
Let me get this in my head before going any farther.
I'm certainly interested in this thread. I have a small room. Lots of bass trapping, and the whole issue of having to place my speakers close to the front wall is of interest. I would like to know what the Schroeder value is all about. Couldn't find a good description of it. My room is 10' 5" x 11' 8" x 8' . The whole rear wall is bass traps. Front two corners bass traps, and 1st point reflection as well. Sheetrock ceiling and carpet floor. Small... yes...
An issue I have is if I set up facing the short wall, the wall behind me has a total of three doors. (I'll try to post pics later,) in one corner is isn't an issue because the door is three and a half feet from the corner. However, the other corner has a door leading to the hall, and a closet it door. One door is only three inches from the corner while the closet door is only seven inches from the corner. I don't see how I can place a base trap in this corner, and setting up facing this wall is not possible either. I do understand why it is best to set up facing the short wall. What are my options here in my room. 14'4" x 11' 6" x 8'. Countless primmer's I've read say if I set up facing the long wall, so I have corners that can be trapped, that I'll never tame the sound in here at all.
paddedcell
Doggy Claws
This is a really interesting thread. I'm stuck with a really small studio space at the moment, measuring 7' by 9' with a 7' ceiling. I have bass traps in the front corners (on the short wall), behind the monitors, and on the walls to the side of the monitors. The rest of the studio has equipment lining the walls, except for the door at the back.
John, you mentioned bass frequencies "folding around" the monitors, and it made me wonder whether I need to treat the walls behind the equipment (i.e. keyboards and racks). I had been under the impression that the profusion of gear would break up most of the reflections from the side walls behind me and the back wall, but now I'm wondering if that really applies to bass frequencies.
Should I be thinking about 703 panels behind the equipment (particularly the keyboards, I guess, since the racks are flat surfaces unto themselves)?
John, you mentioned bass frequencies "folding around" the monitors, and it made me wonder whether I need to treat the walls behind the equipment (i.e. keyboards and racks). I had been under the impression that the profusion of gear would break up most of the reflections from the side walls behind me and the back wall, but now I'm wondering if that really applies to bass frequencies.
Should I be thinking about 703 panels behind the equipment (particularly the keyboards, I guess, since the racks are flat surfaces unto themselves)?
ashcat_lt
Well-known member
This is a pretty common situation, and while I'm not an expert, I think I can offer a little advice that I've picked up around the net.
1) There are 8 other corners in your room. Look for places at the wall/floor and wall/ceiling corners where you can put traps. Putting things on the floor tends to make a small room even smaller, but you could maybe go under your desk and other gear. You'd have to figure out how to hang them across the ceiling corners. The doors on the back wall will be in the way of this also, but it still opens up a lot of places to stick traps.
B) What's in the closet? Can you put bass traps inside there? You could leave the door open. I'd probably just remove it altogether, but unless it's a real heavy solid door the bass will blow through it anyway, so you could probably just leave it closed.
III) The hallway itself is a kind of bass trap. Leave that door open (or not, unless it's actually heavy enough to block the sound) and the bass freq's just keep going down the hall instead of bouncing around inside your mix room.
In fact a small, poorly insulated room where you can hear everything that happens in the next room is actually a bigger room in terms of low frequency response. We always talk about isolation and trapping - keeping the sound in the room and then trying to stop it bouncing around. But if you just let the sound out, it cant bounce around, right? I am sure that this is an important part of the reason my mix room sounds so good. Even at reasonable levels, you can hear my monitors (especially the subs) everywhere in the house.