Building a mixing/post room in an interesting space

[Chris Twofour]

Hey all,

First post on the forum (which is a little nerve wracking ), I've gone and read all the stickies and been through a few hundred pages of threads here and I haven't seemed to find anything close to the current situation that I have so I seek your sage advice.

Been writing/producing music for 12+ years. Recently got a new space for a good rate and want to make it the best I can acoustically before moving in to work.

My mains are Neumann KH310. I also have ADAM A3X's and a pair of Avantons and a Yamaha HS80 Sub.
I use and Antelope Orion 32+ AD/DA and an Antelope Satori monitor controller/Summing mixer (for all the speakers). I already have a bunch of absorption panels, bass traps and clouds (open back) which isn't part of my current budget.

I'm really want to go soffet mounted with the KH310's (because the results are amazing from what I've read and seen here) but the logistics/dimensions of the room are making me think twice. My main issue is I don't own it and don't want to go to crazy beefing it up to only have to leave at some point. The space is not perfect but it's all I have and I want to make it the best I can, I'm committed to putting at least $2000.00 to $3000.00 into as it's not permanent (yet, It might be in the future but that's at least half a year away)

The space is on the second floor of the building L = 15' W = 8' H = 15' (with a 9' T-bar ceiling). It's in a commercial building and in a commercial area so after I'm off at my day job and head over there isn't anyone to compete with for sound. I can be a loud as I like and it's seemingly quiet. To the left of this room is another one, identical (they just built a wall down the middle (under the T-bar) to the right is a huge warehouse where it's a print shop (basically void space) but the drywall goes all the way up so I can't see past into the warehouse.On the side with the door is the lobby of the entire studio. On the other side of the lobby is another room the size of both the 2 smaller ones that is used by a video guy (he's there twice a month) I can see all the way to the other studio above the T-bar.

I've attached some super basic sketchups to show door position, 38% mix position and the T-bar ceiling. The walls are all 1/2" drywall from what I can tell, the floor is laminate and the ceiling at the very very top (15' up) is steel. There are steel trusses up 2' above the ceiling tile which I didn't draw in yet. I've considered things like hanging the speakers from springs, hanging the clouds etc. I also wanted to us ceiling tile grid stagger with normal panels to make the whole upper area a hanging baffle bass trap

As far as HVAC goes, there isn't any but when I go up above the T-bar I can see the entire floor I'm on, so I was thinking of just hoping the grid ceiling tile will keep the air moving.

Question 1:
In the case I just build some large super chunks in the corners and continue to leave my speakers on stands and treat the room like I normally would how do I treat that ceiling?

Question 2:
When using modes calc's I can see my resonant frequency is 37.6hz, how big of a super chunk would I need to build to tame that?

Question 3:
If I were to do soffet mounting (or even super chunk/stands) how high up do I continue to build them?

Question 4:
If I did turn that whole upper area into a hanging baffle bass trap what would the benefits (if any) be?

If you need more info on any aspect let me know and I'll try me best to provide it.

Any information/advice you can pass along to me would be greatly appreciated, don't be gentle.

Thanks,

Chris

[Chris Twofour]

Here is an idea of the entire space with some dimensions.

[Chris Twofour]

*Bump* *Bump* *taps mic* is this thing on?

[Paulus87]

Question 1:
In the case I just build some large super chunks in the corners and continue to leave my speakers on stands and treat the room like I normally would how do I treat that ceiling?

As big as you can, but use low density fibre. 3' would not be too big. But I would build trapping all across the rear wall, by using hanging baffles, then more hanging baffles in the ceiling above your ceiling tiles. You could do 2' - 3' of hanging baffles on your rear wall and then even bigger in the ceiling. Make them with a core of plywood or MDF or chipboard, a lot of people use Homasote (a soft fibre board) but I am a big believer in following Philip Newell when it comes to these devices, and he uses heavy cores. You can use super chunks at the front of your room into which you can flush mount your speakers, that would be a "soft flush" with no baffle extension. If you want a proper hard flush with baffle extension then you can do that instead but it is a very permanent solution.

Question 2:
When using modes calc's I can see my resonant frequency is 37.6hz, how big of a super chunk would I need to build to tame that?

You cannot target that mode efficiently with superchunks, even 2 meters thick would only tame it at about 50% efficiency. But, you may not need to completely kill it, if you build the rear wall hangers and ceiling hangers that will probably be more than enough since your walls and ceiling are fairly "lossy". Also, room mode calculators assume infinitely rigid and dense boundaries, which your room does not have. your entire ceiling area for example extends all the way across to the other room, which means your room volume is actually bigger than you think. A lot of that LF energy is going to leak out of your walls anyway so it will probably not be a huge problem. You can confirm if you have those kind of problems by measuring your room with a calibrated microphone and something like room EQ wizard. Do not base your treatment off of room mode calculators.

Question 3:
If I were to do soffet mounting (or even super chunk/stands) how high up do I continue to build them?

It depends. If a solid, massive, hard flush then ideally all the way from the floor to the ceiling and the side walls. If a soft flush (like super chunks) then as big/small as you want. The more trapping the better.

Question 4:
If I did turn that whole upper area into a hanging baffle bass trap what would the benefits (if any) be?

It's highly recommended. You cannot have too much bass trapping, especially in the ceiling.

Paul

[DanDan]

Welcome Chris. It is a bit quiet here lately. Two of the major contributors are MIA, so Paul and I try to help out. I had S3A for a time, then moved to KH310. German tech rocks eh? I don't think that budget could achieve soffit mounting. In my CR I could install only 3 of the larger SSCs. They halved the length of a very strong 35Hz Mode in this concrete walled and floored room. Your boundaries are light so I expect your modes will be relatively weak. I believe you will be able to treat this room very easily using the old SSC, your lucky suspended ceiling and the typical GIK 244 /MiniTrap/DIY panels.
Then higher up to fully pro level,there is a tried and tested simple and affordable methodology free to borrow/copy.
Boggy, sadly RIP, treated many studios to full EBU performance standards and better typically using 60cm of inexpensive light fibre in simple deal frames.
He even had stand off framing which could be simply removed when say a lease is up.
He shared photos of his builds on Facebook and Instagram. Bogic Petrovic MyRoom Acoustics.
He also shared final test results. A generous open man.
You will see that he clads the inner surface with arrangements of nice looking lath. Many designers do this, including angling the laths. Take a look at the wonderful Bunker Studios by Rod Gervais. The amount of this can be to taste, indeed some of us are quite happy mixing in the typical anechoic response of a Reflection Free Zone.
Check the tiles in your suspended ceiling. If necessary replace them with fully absorbent one. Autex do a nice polyester, but Armstrong and such have absorbing only versions. High NRC, but look for very low CAC (blocking) figures. I would fill the void above the tiles with light cheap attic insulation. Knauf Ecose is nice to work with.
Salud Boggy.

Boggy.jpg

[Chris Twofour]

Hey guys thanks for the replies. Lots of good info!

You're both right the room is rather leaky, I set up my mains on some stands with sorbithane half circles and in the empty room it still had a really tight low end and great image with no treatment at all.

I'm just going to use roxul safe n sound and build floor to ceiling chunks in all 4 corners, make and hang a 5 x 4 cloud above mix pos and use my already owned panels to treat reflections.

I'm ordering some fabric from gilford of maine to cover the chunks with. I'm keeping it simple as it's not my forever studio yet. I'll look into the absorbent ceiling panels thanks for that tip.

I ran REW in there I've posted the results attached...

Anyone know how I would treat those nasty dips at 100hz and 270hz. Would I use a passive EQ on the monitor channels to compensate or is there an actual fix using treatment so I can avoid coloring what I hear from my speakers?

REW, mic and interface were calibrated based on Soundman2020's guide found here..measurements were also taken how he wanted.

http://johnlsayers.com/phpBB2/viewtopic.php?f=3&t=21122

If it would benefit by me uploading the measurement files let me know

Thanks,

[Waka]

Hi Chris, welcome to the forum!

You've got a pretty cool space there. If you end up considering it for a permanent home, do come back here for advice before you push the button.

REW, mic and interface were calibrated based on Soundman2020's guide found here..measurements were also taken how he wanted.

It seems like your measurements didn't quite match those instructions. It looks like you'r levels in the room are a lot lower than the 80dB recommended by Stuart. Did you calibrate the speaker levels with an SPL meter (or an iPad app)?

It's quite difficult to tell what's going on with those images. Can you upload the mdat file to onedrive/dropbox for us to look at please?

Anyone know how I would treat those nasty dips at 100hz and 270hz. Would I use a passive EQ on the monitor channels to compensate or is there an actual fix using treatment so I can avoid coloring what I hear from my speakers?

REW, mic and interface were calibrated based on Soundman2020's guide found here..measurements were also taken how he wanted.

Are these measurements for the empty room, or after you have placed your treatments? If you have already placed your treatments, can you take some pictures of the setup and post them along with the mdat file please.

There are two main types of destructive interference, resonant and non-resonant. The two massive nulls you have appear to be non-resonant, although it's difficult to tell form the images provided and the speaker levels.

Can you re-calibrate REW and your speaker levels following Stuarts guide again, but calibrate to 80dB at least. That should be a bit easier for me to tell what's happening.

We could get more info from the ETC graph in the mdat file, when it's available.

The nulls are likely caused by specular reflections that are out-of-phase with the direct sound.
How are you treating your early reflections? Side walls/back wall/ceiling, and have you got your desk in the room yet?

Can you measure the distance from your speaker cones to the front wall (behind the speakers) too?

Dan

[DanDan]

Welcome Chris. Could you post the .mdat file that you have please. Even if your level was a bit low, REW can 'see' down into the noise floor, so we should be good to go.
If you drop the lower limit on your graphs down to say 25-30dB they should display the room a lot better.
Also if you tick the 'normalise to peak level' in the Spectrogram it should light up a bit for us.

[Chris Twofour]

Hey all,

Thanks for the feed back. I did use my SPL meter to calibrate everything properly. Was playing with the "limits" function in REW so may it isn't as raw as you would have expected. This first measurement is a completely empty room (including me) and it does 2 passes all based on his guide.

The mdat and interface cal file is here...

https://www.dropbox.com/sh/tg3vqj24nadh ... _XVNa?dl=0

I'd like to mention I hadn't gotten the mic cal file before taking this reading.. not sure if its all screwed up because of that...

I have started to build in the room now though. I've got the frames of the chunks installed and just hung the cloud.

The safensound roxul order is coming up next...

[Chris Twofour]

Hi Chris, welcome to the forum!

You've got a pretty cool space there. If you end up considering it for a permanent home, do come back here for advice before you push the button.

REW, mic and interface were calibrated based on Soundman2020's guide found here..measurements were also taken how he wanted.

It seems like your measurements didn't quite match those instructions. It looks like you'r levels in the room are a lot lower than the 80dB recommended by Stuart. Did you calibrate the speaker levels with an SPL meter (or an iPad app)?

It's quite difficult to tell what's going on with those images. Can you upload the mdat file to onedrive/dropbox for us to look at please?

Anyone know how I would treat those nasty dips at 100hz and 270hz. Would I use a passive EQ on the monitor channels to compensate or is there an actual fix using treatment so I can avoid coloring what I hear from my speakers?

REW, mic and interface were calibrated based on Soundman2020's guide found here..measurements were also taken how he wanted.

Are these measurements for the empty room, or after you have placed your treatments? If you have already placed your treatments, can you take some pictures of the setup and post them along with the mdat file please.

There are two main types of destructive interference, resonant and non-resonant. The two massive nulls you have appear to be non-resonant, although it's difficult to tell form the images provided and the speaker levels.

Can you re-calibrate REW and your speaker levels following Stuarts guide again, but calibrate to 80dB at least. That should be a bit easier for me to tell what's happening.

We could get more info from the ETC graph in the mdat file, when it's available.

The nulls are likely caused by specular reflections that are out-of-phase with the direct sound.
How are you treating your early reflections? Side walls/back wall/ceiling, and have you got your desk in the room yet?

Can you measure the distance from your speaker cones to the front wall (behind the speakers) too?

Dan

the distance from the speakers to the back wall is like 20 inches at max might be even closer. The Neuman setup guide says anything less than .8 of a meter is okay (not terrible) for SBIR. The room is all steel stud and 1/2 drywall I'm sure so there isn't a whole lot of bass reflecting in there.

There is no treatment, furniture or anything in there during this reading. I have tons of panels from my last setup so treating the first reflections etc will be a breeze i just wanted to give the room a big head start before bringing in the treatments.

[Waka]

Hi Chris,

I'd like to mention I hadn't gotten the mic cal file before taking this reading.. not sure if its all screwed up because of that...

I have started to build in the room now though. I've got the frames of the chunks installed and just hung the cloud.

The safensound roxul order is coming up next...

I wouldn't worry too much about not having the cal file for the first measurements. Calibration files tend to do more for the high end where direction is more important. I'm mainly concerned with the low end and early reflections at this stage.

Can you give specifics about the cloud:
How is it constructed?
What is the size and distance from the suspended ceiling and outer ceiling?
Is it angled at all?

Also did you put additional absorption above the suspended ceiling?

The mdat and interface cal file is here...

Looking at the REW data is helpful. Although you calibrated the speakers, it's possible you just didn't set the levels in the REW SPL meter. It looks like REW is recording the levels about 10dB lower than the actual levels.

Can you model your speakers, mix position and the treatments you've added so far in Sketchup?

To give more detailed response we need the location of the acoustic axis of each of your speakers, ie. the distance from each surface;
and the same for your mix position. We also need the distance of your mix position from your speakers, and the angles of the speakers.

Some initial thoughts:

Your null at 168Hz agrees well with probable BIR from your front wall (speakers being 20" from the front wall).
How deep are your speakers?

If there is more than a 4" gap between them and the front wall, hang 4" of insulation on the front wall behind them and push the speakers back to lightly touch the insulation.

Your strongest early reflection is at 6.05ms, if we know the distance between your speaker and mic, we can work out the approximate distance this wave traveled, so you cna use the "string trick" to find it. Although here's what I think it is: It's very strong, so not a lot was absorbed, so probably reflecting from concrete. It's too late for a floor reflection so it's probably your side wall first reflection points.

- Do you plan on treating this with absorptive panels?

The reflection at 3.34ms is probably your floor reflection.The stuff at 3.93ms could be your ceiling, as it's a suspended ceiling, only some frequencies will be reflected.

- A well placed desk can tame your floor reflection well, the ceiling reflection should be fine now you have your cloud installed.

The reflections near the 15ms mark seem to be rear wall.

- What do you plan for your rear wall?

Those additional measurements would be great if you can provide them.

Dan