3d model of a room I could use help on

[ffrgtm]

Hello everyone,

Working in a little room where me and at least one professional like to dj on the week nights. Located in an area where sound containment isn't an issue... but as you can see the room is medium sized and quite tall, with a sloping ceiling (room dimensions are symmetrical so understand that the ceiling when viewed from the x,z plane is a line) so the reverberations in the room are horrible. The floor is carpeted but everything else is a hard surface.

I'm unsure what the proper orientation is for the table, there are two 8" monitors on it for the dj and I have a kef downward firing subwoofer (from a home stereo) under the table. Also have 2 15" pa speakers facing away from the table. Realize that all of this can be moved around per recommendations .

To deal with this issue, I have built 18 2'x4' 2" thick bass traps with rock wool. I decided to only go with the 2" so I could afford to build 18 of them... I have a lot of surface area to work with here.

I am also capable of putting blankets on the walls/ceiling to help with the higher frequencies.

Can anyone help me with the orientation of the speakers and basstraps to get the best sound for both the dj and listeners in the room?


Thank you all very much for your help... I spent a little time making this sketchup model to make myself easier to understand.

 

[ffrgtm]

How does this look? I have four traps left... 2 to go behind wall the monitors are facing and two to go above the pa's on the ceiling.

Should I be focusing on putting something at the level of the kef sub though?

Thanks for any and all advice

 

[c7sus]

The traps look good for placement. The last four traps should go opposite the 4 wall-mounted traps.

But I would put the PA speakers and the DJ table on the wall with the 3 traps in each corner. The PA speakers a couple feet in front of the traps.

Putting two traps on the ceiling probably won't do much that is noticeable.

If you had a few more traps for the ceiling the best use might be hanging them horizontally so they aren't flat against the ceiling.

Something like this if viewed from the top, so they overlap each other. Probably in the middle third of the room.

_ _ _
. _ _
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[ffrgtm]

Wouldn't the sound bounce off of the hard cabinets and mini fridge then?

 

[RICK FITZPATRICK]

To deal with this issue, I have built 18 2'x4' 2" thick bass traps with rock wool

Warning: NON EXPERT opinion coming. My disclaimer is in full effect here.


I'm a little confused.To WHICH issue are you referring, as you don't really mention any issues other than your table location, which has little to do with the so called "traps". Corner placement of traps ARE recommended for small room treatment due to Low Frequencies termination/reflection in corners due to wavelengths equal to room dimensions. And you have placed these in the correct location for the foremost problem with small rooms...ie...LOW FREQUENCIES. However, 2" thick "traps" will do little to absorb these frequencies due to 1/4 wavelength limitations of resistance type absorbers...ie...

2"= 1/4 wavelength = frequency 1673.2 hz...more or less, which is NOT low frequencies.

Therefore I would recommend a new strategy given your financial restrictions.

First, ditto Csus on relocating your desk and PA speakers, placing them symmetrical on the long axis of the room.

Second, the term "trap" is a misnomer as used here. These are NOT bass traps. However, I'd move all the absorbers from this wall, to the rear wall corners, doubling up the thickness of the existing ones there. This is for FIRST REFLECTION of LF in the rear corners. Since this is not a typical Control room configuration, front wall absorption is not critical, as the direct sound from the PA speakers is more important than your monitoring speakers. However, since this is a VERY small room, and you've already built these absorbers, positioning for as much "trapping" as you can afford is my recommendation.

Although, if you are able to modify the ones on the side wall, personally, I'd cut these down to 2'x2', and space them in a checkerboard fashion, leaving about 12" between them. And mount them with a 2" gap behind them as well. This will provide a modicum of "diffusion" as well as some "broadband" absorption at the side walls.

But bear in mind, small rooms require massive amount of thick absorption in correct placement, usually via SUPERCHUNKS in ALL corners, including those at the wall/ceiling intersections, in order to deal with low frequencies. However, this isn't a control room where monitoring accuracy is the main criteria.

Personally, it's my opinion that breaking up reflections is the main issue here, as you really don't have the resources to "suck up the mud'...so to speak. So...you end up with what you have...specular reflection off the cabinet, which is no different than the wall behind it,..with a modicum of bass trapping and first reflection absorption/diffusion thrown in the mix. And there are no opposing surfaces with no absorption..except for the ceiling/floor. Which in this case, can not be addressed due to lack of resources, although, the slanted ceiling will help to a degree.

Furthermore, I don't know how many people you a DJ'ing for in this small room, but as people fill the room, even 3 or 4 will help with absorption, and will be between the speakers and the rear wall. So don't worry about it.

One other thing. I don't know why you are using the small monitors. This is a very small room and frankly, my guess is, firing in the opposite direction from the mains will have a somewhat "smearing" effect on the sound from the mains, as there is a time delay between the sound of the mains and the reflection from the monitors, due to the travel path to the boundary. Small, but nonetheless..delayed.
Hence the use of absorbers on that wall.

Here is what I'd do.

Anyway, so much for my "non expert" opinion. BTW, MY control room is EXACTLY the same size. Holy moly! I can't imagine more than 4 or 5 people in there. But I'm an old fart. Who are you DJ'ing for anyway?

fitZ

 

[ffrgtm]

Thanks for the awesome information! We usually only dj for around 10-20 people, ultra exclusive club In these situations people seem to prefer to be packed in a small space, that way it's harder for people to make out the ridiculous arm flopping they're trying to pass off as dancing (myself included). Would it be wise for me to double my material and go 4" thick and just throw half of my frames away? I was planning on using blankets on the walls for "diffusion". How important is it to set the table up lengthwise?

The monitors are there just to have a clear picture of what you're playing the opposite direction... I had wondered how they interacted with the pa's though.

 

[ffrgtm]

Oh sorry, and the issue was the "echo" in the room. Even in a normal speaking voice you could hear it... if you slapped the level faders down I swear you could hear reverberations for a good 1/3 or 1/2 second standing near the source.

 

[RICK FITZPATRICK]

We usually only dj for around 10-20 people

In THAT room?? GAK! They'd make one big absorber anyway!

that way it's harder for people to make out the ridiculous arm flopping they're trying to pass off as dancing

I bet. They'd be packed in like Sardines! No room to "flop around arms" for sure.

Would it be wise for me to double my material and go 4" thick and just throw half of my frames away

If you can't buy more, do what I showed. That's 14 panels. Otherwise, you need to purchase enough absorption material to make REAL Superchunks. That is...if you want to make the room "disappear", so to speak, so the room isn't coloring the sound. Bass will appear STRONGER and clearer, even though you are absorbing Low frequencies..and that's the point. Although people will absorb too, it's only in the high Mids, and hi frequencies.

As to the "echo"...that's when the room is empty...no? 10-20 People SHOULD have an
absorbing effect. But even then, thats why I distributed your panels in a patchwork fashion to break up specular reflections from the side walls. What you are probably hearing is the low end DECAY. Without being there to hear it, it's difficult to say, but you might even be experiencing "flutter echo", as your room size is perfect for this. Those patchwork broadband absorbers will help with that if that is the case.


And frankly, as a DJ, I'd suggest using headphones instead of another set of monitors facing you. They wouldn't tell you the truth anyway. Not in this circumstance. Sound from the mains/reflections will color what you hear from your small monitors..so what's the point? And if you DO use headphones, you can use the absorbers from that wall to add to the "superchunks" at the rear wall, as the front wall will need little or no absorption now. There isn't enough to make "true" floor to ceiling superchunks, but do the best you can.

Let me say this though. AGAIN..small rooms are the shits for Low frequency modal resonance, and it takes a LOT of absorption to tame it. Of course, this is a DJ room...not a recording studio and you are the only one who can define what you hear prior to treatment and after. You don't have a lot to work with..absorption wise, so I just tried to put what you have to better use in that regard. Good luck with your sessions and have fun!

 

[RICK FITZPATRICK]

On second thought, leave those absorbers at the front wall. Try that first. If this layout doesn't help with your issues...well, then add them to the "superchunk diagonal panels.