John Sayers' Recording Studio Design Forum Archive

Room: 3.24 m Long 2.34 m Wide 2.24 m Tall

Pre-built Soffits: Two Studios, ago I spent a significant amount of time researching and building a flush mount speaker system based on John's design and various other builds on the forum (I will post pics of that build for fun). The results of which are fantastic and ultimately ended up being portable! (my restrictions for building have been and continue to be space or lack there of)

1) Should I bother with the first reflection angled slat walls? (to get my 12 degrees of splay I've had to bring the soffits together... sacrificing sound stage)

2) Is it practical to use the extra space to the side of the soffits for hangers as shown? (or should I just stick to broadband absorbers with high frequency diffusion and use that empty space as part of the cavity?)

3) Is it realistic to put a panel absorber on the door? (to try and mirror some bass absorption from the corner trap opposite?)

4) I was planning to build a multi angle cloud into the room at 12 degrees over the mix position and then angle it back towards the rear wall (hopefully achieving some extra bass and low mid trapping functionality) Is there any suggestions on what the back wall absorption strategy should be?

5) I wanted to add two more Low-Mid/Bass absorbers on the last two parallel walls and was considering John's Curved Panel Absorber http://johnlsayers.com/Recmanual/Titles/Acoustics2.htm in order to retain some high frequencies in the room. Does anyone have any thoughts for or against?

I realize that my options are severely limited and any results I can achieve will be less than ideal given the excruciatingly miniature space my wife has allowed me to occupy for this latest endeavor...
so I greatly appreciate in advance any and all opinions, direction, advice, criticism, humor! assistance and time that the community my have for me.

Gregwor wrote:Hey, another Albertan! Hope you got out to vote today!

Howdy Greg! Great to see another Albertan indeed! I voted last week lol I couldn't wait to exercise my civic right!

Room: 3.24 m Long 2.34 m Wide 2.24 m Tall

Small sucks but at least you have a room. A small room is better than no room!

Yes you are totally correct! I am happy to have a small corner for my recording addiction!!

Pre-built Soffits: Two Studios, ago I spent a significant amount of time researching and building a flush mount speaker system based on John's design and various other builds on the forum (I will post pics of that build for fun). The results of which are fantastic and ultimately ended up being portable! (my restrictions for building have been and continue to be space or lack there of)

This could be more rigid overall in my opinion. Especially since you aren't decoupling your speakers. Could you add some 2x4's on edge underneath of the shelf?

Hmmm, I haven't noticed any rigidity issues? (each complete soffit weighs almost 400 lbs!!) although I suppose I could add even more mass by doing what you suggest if you think it would result in better infinite baffle response! Please advise?

1) Should I bother with the first reflection angled slat walls? (to get my 12 degrees of splay I've had to bring the soffits together... sacrificing sound stage)

Have you ray traced your SketchUp yet to see what you need to do to obtain an RFZ sphere around your head at mix position? The 12 degree thing does not help you here. That's a fine guideline for the rear half of your room or a live room, but if you're soffit mounting your speakers with large baffles, trying to obtain an infinite baffle design, you need to build your soffit wings to give you an RFZ and reflect sound towards your rear wall. Your rear wall will have to be very deep absorption in order to attenuate your first reflections.

Interesting, I hadn't picked up on that 12 degree distinction in previous threads but it works for me and does make sense (there seems to be a lot of designs and direction surrounding 12 degrees for splayed wings even with soffit mounted speakers...?) Also, I have not ray traced my sketchup yet but I will do so and post the results! Regarding the design of the Soffit wings (once I have the angle calculated)... Should I bother with a slat design? Even trying a tuned Helmholtz resonator? I'm worried about losing all my highs as the bass trapping is going to be as aggressive as possible in this tiny room...

Also, at what percentage depth-wise in your room will you have your head?

My head will be at the equilateral triangle peak (ideal listening position) so, approximately 40 to 45% into the room I would guess?

EP Studios SWEET SPOT.jpg

2) Is it practical to use the extra space to the side of the soffits for hangers as shown? (or should I just stick to broadband absorbers with high frequency diffusion and use that empty space as part of the cavity?)

The cavity looks small enough that you might be better off just filling that space with insulation.

3) Is it realistic to put a panel absorber on the door? (to try and mirror some bass absorption from the corner trap opposite?)

I don't see a door in your SketchUp so I can't comment on this.

Sorry I thought it was obvious from my drawing... LOL See below!

EP Studios DOOR.jpg

4) I was planning to build a multi angle cloud into the room at 12 degrees over the mix position and then angle it back towards the rear wall (hopefully achieving some extra bass and low mid trapping functionality) Is there any suggestions on what the back wall absorption strategy should be?

Ignore the 12 degree rule here. You need to angle is such that you have an RFZ. That's the goal.

Yup! I will get the ray trace done and submit my modified design around that!

Your rear wall ideally should be 2 feet thick of hangers. If you can't spare that much space, make it as thick as possible. Minimum I'd ever go is 6". 24"+ is ideal.

With that in mind I will amend my design to include a radical 24" cavity on the back wall /ceiling area to create maximum hanger space!

5) I wanted to add two more Low-Mid/Bass absorbers on the last two parallel walls and was considering John's Curved Panel Absorber http://johnlsayers.com/Recmanual/Titles/Acoustics2.htm in order to retain some high frequencies in the room. Does anyone have any thoughts for or against?

That could be great. Obviously you're going to need something there. I wouldn't commit to anything at this point though. If you've followed many threads on the forum you'll see that the best way to treat a control room is one step at a time. Install a device, take acoustic measurements and then design/build the next device accordingly.

This will be my Operating Procedure moving forward! Measure, Test, post results, build, install, test and Measure again! Rinse! Repeat!!

I realize that my options are severely limited and any results I can achieve will be less than ideal given the excruciatingly miniature space my wife has allowed me to occupy for this latest endeavor...
so I greatly appreciate in advance any and all opinions, direction, advice, criticism, humor! assistance and time that the community my have for me.

My biggest fear for you in HVAC. What is your plan with that? Clearly you don't have the space or maybe even the need for isolation.

Also, not shown in my drawing is the HVAC inlet above the mix position, I'm thinking I might have to do some sort of exhaust air vent type scenario (maybe over the door built into the ceiling treatment...) but in terms of isolation, yes I'm not too concerned!

Again, I'm glad to see another AB homie on the forum! Cheers!

I'm super excited for the help Greg! Thanks so much for responding, I apologize for my late reply (I was detained with work and my young children LOL) I will endeavor to respond sooner should you be able to keep working with me through my build!

Greg

Howdy Greg! Great to see another Albertan indeed! I voted last week lol I couldn't wait to exercise my civic right!

Hmmm, I haven't noticed any rigidity issues? (each complete soffit weighs almost 400 lbs!!) although I suppose I could add even more mass by doing what you suggest if you think it would result in better infinite baffle response! Please advise?

Interesting, I hadn't picked up on that 12 degree distinction in previous threads but it works for me and does make sense (there seems to be a lot of designs and direction surrounding 12 degrees for splayed wings even with soffit mounted speakers...?)

Regarding the design of the Soffit wings (once I have the angle calculated)... Should I bother with a slat design? Even trying a tuned Helmholtz resonator? I'm worried about losing all my highs as the bass trapping is going to be as aggressive as possible in this tiny room...

My head will be at the equilateral triangle peak (ideal listening position) so, approximately 40 to 45% into the room I would guess?

Sorry I thought it was obvious from my drawing... LOL See below!

With that in mind I will amend my design to include a radical 24" cavity on the back wall /ceiling area to create maximum hanger space!

Also, not shown in my drawing is the HVAC inlet above the mix position, I'm thinking I might have to do some sort of exhaust air vent type scenario (maybe over the door built into the ceiling treatment...) but in terms of isolation, yes I'm not too concerned!

I apologize for my late reply (I was detained with work and my young children LOL)

Gregwor wrote:Crazy how Edmonton was all orange and the rest of the province was blue!!!

Gregwor wrote:For the baffle, mass is EVERYTHING. This is necessary to properly direct the low frequencies as per the infinite baffle analogy.

Gregwor wrote:12+ degrees is necessary as you're informed. However, due to the wavelength of low frequencies, you'd need an insanely long wall at 12 degrees for this to take effect at problematic frequencies. Basically, don't get hung up on it for your small room.

Gregwor wrote:There is a room very similar to yours pretty much done on the forum somewhere. I don't have the time to look for it right now but I think it's in "other studios" forum.

Gregwor wrote:John Brandt incorporates a lot of slat design in the front half of his listening rooms. Personally, I'm not sold on the idea as maintaining high end in a room with insane amounts of insulation (required for bass frequencies) is difficult enough

Definitely says something about the demographic of Alberta for sure... I work in Oil & Gas so you can guess which way I voted

So, even though these soffits are completely built already, by adding lumber to the bottom of the individual speaker shelves you believe the low end response of the baffle itself could be improved? (I could add 2x6's glued and screwed together for the extra mass, it would just eat into the superchunk roxul that's currently under the speaker shelves...) Like this?

Here is my horizontal RAY TRACE.... WOW that took forever!! Still need to do vertical but I'm hoping this can start a conversation about any problem reflections that you see?... I'm happy with the RFZ so far? unless I am missing something?

I think this is the build you are referring to? and YES it is nearly IDENTICAL!! Thanks for that Greg!!
viewtopic.php?f=10&t=21539

In that small room build I just referenced he did "solid" soffit wings ... Should I do the same as a starting point you think? I feel like I should do the exact same superchuck treatment the whole length of the ceiling/wall angle just like he has done... Thoughts?

Also, instead of "hangers" for back wall absorption he did the whole thing in one big superchunk as his research indicated higher bass absorption per square foot of space (as my research also concluded) Do you have thoughts on this?

Thanks again Greg for working through this with me! I will keep updating my design and get my vertical ray trace done... I feel that designing my bass trapping like Martin has done in his build is a good baseline. Seems yourself and Stuart both helped him out a lot and he got fairly awesome results! (I fear my room is slightly smaller than his though...)

Hangers have been proven to kick ass. If you're not handy, superchunk works great. Personally, I'd do hangers though. You won't be disappointed either way.

That looks awesome. Is that the biggest RFZ sphere around your head that you can get? The fact that you got a sphere at all is promising. Just remember that the bigger the sphere, the more you'll be able to lean around without having reflections! The same goes for your cloud design (your vertical tracing fun filled adventure!)

Smaller just means you'll need MORE treatment. So make your rear wall treatment as thick as possible and bass trap the HELL out of every single corner.

I have added Hangers on the back wall (the cavity is just over 2' deep at the narrowest) What do you think of the Hanger sizes and orientation? I can't spare any more room than that unfortunately... The Hanger cavity front wall will be cloth covered roxul, and I will probably put a thin roxul panel on the back of the door to remove that reflection. Thoughts?

Here is the re-tweaked Horizontal RFZ... I managed to increase the sphere and this is probably the best it can get... Thoughts?

So, I am thinking of doing this with superchunks on the wall to ceiling angles where accessible... To maximize bass trapping outside of the hangars. What are your thoughts? is it too much or should I keep it in the design?

Thanks again for your always helpful input Greg, hope things are great in your world

As I get the room framed in I will take acoustic measurements, starting with empty and continue measuring as treatments is added... Are you able to help me analyze the results?

Unfortunately the orientation of your hangers is incorrect. Try having them at around 40 degrees. If you can't make that work, have them all basically straight running front to back in your room. Remember, the sound hitting them is going to be coming from every angle imaginable.

Have a look below, if I orient them 40 degrees to the right I can fit 10 hangers, as compared to 9 if I swing them to the left... Which way would be better for the room?

Here is the re-tweaked Horizontal RFZ...

Are you sure that your surface normals really are perpendicular to the reflective surfaces? Many of those reflections seem to not be at the correct angle, for both the soffit wings and the cloud. I would double check that you are doing your ray-tracing correctly.

When you ask if I'm sure that my "surface normals" really are "perpendicular" to the reflective surfaces? I gasp and my mind starts doing back flips as I spent hours scouring the forums and searching your posts on the subject of ray tracing

and if I am interpreting your comment correctly, the surface normals would be the soffits (speakers) themselves? therefore whatever "angle" the soffits are at (mine happen to be 12 degrees) that would be your baseline with the flat face of the speaker representing the full 180 degrees? (Probably not the best explanation... )

For my trace, I then created the rays at 5 degree intervals starting at the full "flat" 180 degree and fanned them out back to center. The reflections themselves are following the laws of reflection in that the angle of incident equals the angle of reflection... (at least I thought so anyway!!?!)

So, where a ray would hit the soffit wing, the incidental angle would be say, 25 degrees I would mirror the 25 degree angle for the reflected ray, Like this: