Help Me Treat My Live Room (Measurements Included)
Aaron Miller
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30th December 2012
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Help Me Treat My Live Room (Measurements Included)

I'd really appreciate some advice from the pros! Here's some background info:

I recently began remodeling a second floor bedroom into a live room. The original thread is here: Second Floor Live Room Help Please!

Over the last week, I ran conduit and put in a laminant wood floor. Now I'm in the process of determining how much OC703 I want to put in the room. I have a whole bunch of it--more than enough--and I'm going to experiment with different amounts until I get the right balance of liveness/deadness. Extra can be used in the control room at a later date. Once I have a balance that is about right, I'm going to determine exactly how I'll frame it in (i.e., inside out wall) and whether I'll also incorporate some diffusion (likely). Below you'll find some posts with images, measurements, and audio. I'll post some specific questions in a follow up thread. Thanks!

Here is the basic floor plan I have in mind. The OC703 (pink in the image) is where I have it currently placed (I believe it's too dead; see below):

Aaron Miller
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Here's where I started a week ago:



And here is the room today, testing with FuzzMeasure:



There are super chunks in three corners and a crapload of OC703 panels stacked up along all walls. It's actually too dead I think. The speaker is sitting roughly where my drums will be placed and the mic is about 4' out in roughly the middle of the room. I understand that doing this type of acoustic measurement isn't all that helpful in for live rooms, but I wanted to get some quick measurements as one point of reference. The other points of reference are my ears.
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Acoustic Measurements

20-500Hz Frequency Response (Orange = Before, Blue = After):


500Hz+ Frequency Response (Orange = Before, Blue = After):


Reverb Time Before:


Reverb Time After:


20-500Hz Waterfall Before:


20-500Hz Waterfall After:
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Audio Files

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You already touched on this - but also opened the door with the test/data - so I would be remiss not to say that I operate under the opinion that it is a total waste of time and energy to even consider testing tracking spaces the way we test listening spaces.

In critical listening spaces the ears are pretty much in the same space - and the sound source is always in the same space.

Picture trying to test a listening space if the sound source was a moving target.

Now - in a tracking space the sound source is just that - picture the wide variety of sources for sound from even a small drum kit.

I cannot see a single benefit from examining the data you have gathered. It does not represent reality when it comes listening to/gathering sound that will be generated in your space.

Rod
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I think testing to see the decay time is fine (and helpful), but the proof really is in the recording.
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Quote:
Originally Posted by Rod Gervais View Post
You already touched on this - but also opened the door with the test/data - so I would be remiss not to say that I operate under the opinion that it is a total waste of time and energy to even consider testing tracking spaces the way we test listening spaces.

In critical listening spaces the ears are pretty much in the same space - and the sound source is always in the same space.

Picture trying to test a listening space if the sound source was a moving target.

Now - in a tracking space the sound source is just that - picture the wide variety of sources for sound from even a small drum kit.

I cannot see a single benefit from examining the data you have gathered. It does not represent reality when it comes listening to/gathering sound that will be generated in your space.

Rod
Yeah, I know the frequency response is not helpful because moving the mic or the speaker even a few inches in any direction makes significant changes to where the peaks and valleys occur and to their depth. Since I already had the computer there to record, I ran the test out of curiosity. I do think it shows some general smoothing, which is going to occur regardless of where the mic/speaker are placed. I think the reverb times confirm what I'm hearing, which is a much tighter, more dead room. There's too much absorbtion of going on at high frequencies.

I like the way the acoustic guitar sounds in the audio sample, but with the mic 24" from the 12th fret, there should be some room sound being picked up. Right now there's virtually none.

The snare sounds really dead and the audio file reveals flutter echo which I believe is from floor-ceiling interaction. If I clap my hands there's a definite "" sound.
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Measures

The Measurements look flawed to my eye. How can a decay be increasing? Feedback?
Until measurements are trustworthy well.....http://www.gearslutz.com/board/studi...er-v2-1-a.html

Drums etc will get maximum LF boost in a corner. Vocals and acoustic are probably best done away from the boundaries.

You have a very large live surface, the floor. The parallel ceiling needs to be highly treated to prevent flutter. Large cloud over drums and over vocalist to begin with. Scattered panels elsewhere. Angled or curved ply or other sheets will also prevent flutter. The walls would probably do a much better job with 50% or less fibre. Alternate fibre and bare wall areas across from each other. Again ply sheets, even polys can also prevent flutter while deliver some woodiness.

DD
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Quote:
The snare sounds really dead and the audio file reveals flutter echo which I believe is from floor-ceiling interaction. If I clap my hands there's a definite "" sound.
Got to only listen from my laptop but I agree. Ceiling absorption is over looked a lot.
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The decay times seem to confirm what I hear: too dead in the high end, which is what people warned me about. So what would a good reverb time chart look like? Is the goal to have similar reverb times across all frequencies? Should I aim for times rangung between .2 - .3 from 60Hz to 12KHz? Or is it generally preferable to have lower times in the lower frequencies?

Are the substantially higher reverb times at 40 and 50Hz troublesome? What about the buildup in the lower mids? Or are the times significantly low so now it's a matter of bring back some high end?


Regarding the balance of reflection/diffusion to absorbtion, I was considering making the west wall the live wall. It would have more reflective/diffusive surfaces. My thinking here is that it's furthest from where the drum kit will sit. The other walls would have more absorbtion. Is this a good approach or would a checker bording it (ie, alternating absorbtion with reflection/diffusion) work better? Thanks!
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Quote:
Originally Posted by Glenn Kuras View Post
I think testing to see the decay time is fine (and helpful), but the proof really is in the recording.
Decay time is a generally local phenomena - not a room wide phenomena - which is why it is so challenging to design even dedicated control rooms with an even response and decay in relatively small areas.....

This can be used to advantage with intelligent mic placement......

Personally - seeing as the sound sources could be located almost anywhere - and the same is true with the "ears" in the room - I have never worried about testing live rooms on any of my designs. Nor have I ever encountered issues related to the same.

Make an analysis of the instruments you wish to record - where you would be best suited to place your mics in order to capture the specific instruments in question - and deal with all of the obvious issues - they are not all that difficult to see.

Rod
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Quote:
Originally Posted by DanDan View Post
The Measurements look flawed to my eye. How can a decay be increasing? Feedback?
Until measurements are trustworthy well.....http://www.gearslutz.com/board/studi...er-v2-1-a.html

Drums etc will get maximum LF boost in a corner. Vocals and acoustic are probably best done away from the boundaries.

You have a very large live surface, the floor. The parallel ceiling needs to be highly treated to prevent flutter. Large cloud over drums and over vocalist to begin with. Scattered panels elsewhere. Angled or curved ply or other sheets will also prevent flutter. The walls would probably do a much better job with 50% or less fibre. Alternate fibre and bare wall areas across from each other. Again ply sheets, even polys can also prevent flutter while deliver some woodiness.

DD
Yup, I noticed the apparently increasing reverb in the lowest frequencies and wonder what's going on.

I'm definitely going to get rid of some absorbtion. Too dead for sure.

The floor ceiling flutter echo is definitely noticeable. You can hear it in the post-treatment snare samble and even more pronounced when clapping one's hands.
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Quote:
Originally Posted by Rod Gervais View Post
Make an analysis of the instruments you wish to record - where you would be best suited to place your mics in order to capture the specific instruments in question - and deal with all of the obvious issues - they are not all that difficult to see.

Rod
Hey Rod, can you expand on this point? It sounds like you're saying I set up, for example, my drum kit, mic it up in a standard way, and then experiment with not only the position of the kit in the room but also the amount/position of acoustic treatment. This is something done entirely by ear, correct? (Or does some kind of analysis tool also come into play?). Thanks!
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Quote:
Originally Posted by Rod Gervais View Post
Decay time is a generally local phenomena - not a room wide phenomena - which is why it is so challenging to design even dedicated control rooms with an even response and decay in relatively small areas.....

This can be used to advantage with intelligent mic placement......

Personally - seeing as the sound sources could be located almost anywhere - and the same is true with the "ears" in the room - I have never worried about testing live rooms on any of my designs. Nor have I ever encountered issues related to the same.

Make an analysis of the instruments you wish to record - where you would be best suited to place your mics in order to capture the specific instruments in question - and deal with all of the obvious issues - they are not all that difficult to see.

Rod
You and I are closer then you think but to check decay is still helpful. If you don't do it then fine but if someone else does it then it is not wrong.
All the best.
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Quote:
Originally Posted by Glenn Kuras View Post
You and I are closer then you think but to check decay is still helpful. If you don't do it then fine but if someone else does it then it is not wrong.
All the best.
Glenn,

And all the best back at you my friend........

Not suggesting wrong versus right here....... we all have to do what we have to do my friend.

Rod
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Quote:
Originally Posted by Aaron Miller View Post
Hey Rod, can you expand on this point? It sounds like you're saying I set up, for example, my drum kit, mic it up in a standard way, and then experiment with not only the position of the kit in the room but also the amount/position of acoustic treatment. This is something done entirely by ear, correct? (Or does some kind of analysis tool also come into play?). Thanks!
Aaron,

I've designed (and set up) a lot of live rooms - and have never bothered to test any of them..... There are huge differences throughout a room when tracking as opposed to always sitting in the same spot with the same sound source - I have never found an upside to bothering with room tests for live rooms - this is a personal philosophy rather than a signed in blood rule - however I have designed a lot of live spaces that are quite loved using this philosophy.

In rooms I just set up in (rather than design) I always lean towards corner sets for drum kits - close mic the kit, although if I have a decent room I will also set some room mics to capture the kit in the room as well - I provide absorption over the kit at the very least....... quite often behind the kit if needed - gobos if I want to record other instruments in the space at the same time.

I play around with amp locations to find the best spots - but do not get all that anal about it - close micing with the right microphone will go a long way towards giving a good amp sound. DI is always an option if you want to capture what you can without bleed into the drum mics (for instance) and dub in afterwards.

This is not the same as saying that one should not bother to think about their approach to room design for a live space - just that once you work your way through it - just build it and use it.......

Rod
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Hi guys. I am going through a similar stage as Aaron. I have the live room drywalled and ready for paint and treatment.
Its a fairly large room with about a 3 second decay time.
Concrete floors and drywall everywhere else.

I need to find some ways to drop the decay down a bit but i want to be careful about not just taking all the high end off.
Bass traps aside for now, is the best approach to start with wide band absorbtion, say 4" of 703 placed in various spots, which i understand goes down to around 100hz?
The ceiling is vaulted and not parallel with the floor and most all walls are not parallel.
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Quote:
Originally Posted by Rod Gervais View Post
- I provide absorption over the kit at the very least.......

Rod
How do you go about that in a large open room?
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Quote:
Originally Posted by GreenNeedle View Post
How do you go about that in a large open room?

Construct a cloud and hang it from the ceiling above via hooks/chains, nothing strange here..

Rod
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Quote:
Originally Posted by Rod Gervais View Post
Construct a cloud and hang it from the ceiling above via hooks/chains, nothing strange here..

Rod
Oh i thought you meant a temp solution in a studio you might visit to track in.
The advantage of the cloud is mostly for what, focus of the sound of kit?
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31st December 2012
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The cloud could always be hung using a temporary device - a freestanding frame made from PVC or aluminum tubing.

The purpose of the cloud is a avoid early reflections from above - you don't need early reflections from above getting back into those mics. This assumes (of course) that the room has not been designed to handle those reflections in another manner.

Rod
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More Questions

Thanks everybody for the excellent advice. I've been doing lots of experimenting today. A few questions:

*Flutter echo issue:
https://soundcloud.com/aaronmillerproductions/flutter-echo
This is also evident in the snare drum audio sample above. It's a floor-ceiling flutter echo that pretty much disappears when I put heavy blankets on the floor. I'm thinking I need to figure out my ceiling treatment before or at least during my wall design. Otherwise, this problem will be impacting every decision I make. So with 8' ceilings, what would be best: 2" OC703 panels (directly against ceiling or hanging?) or some diffusion or a combination?

*50Hz Issue: I've tried various speaker positions (around where I'll have my drum kit) combined with various different mic positions. All seem to reveal a big dip around 50Hz. It shits from 40-60Hz depending on exactly where things are placed and gets slightly worse or better, but it seems this is consistently a problem area. The reverb times are around 0.4 whereas at most other frequencies they're at around 0.2. It seems the OC703 has greatly reduced reverb times above this range and I've confirmed this with various mic locations and speaker locations. Seems to be a general room problem. How effective is OC703 in this range? I already have corner chunks in three corners and could even put 2" panels in front of them but I don't want to lose too much space. Given that I'll be close mic'ing my kick and usually record bass DI, should I even be worrying about what's going on at 50Hz in my live room?

*Approach to placing absorption. As far as combining absorption with reflection/diffusion, would a checker board approach be better than, say, treating 2-3 walls with pure broadband absorption and the remaining with reflection/diffusion? I'll of course have super chunks in the corners and regardless.
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4 by 4 by 4

Aaron, I have grown to think in Fours.
Four inch traps, hung with a four inch airgap. A decent number of those will have a go at the 70Hz Height mode and more importantly it's multiples.
Four of them over the kit. Four over the vocalist. Just for starters.
A 50Hz Null could well be SBIR. Close miced drums will not experience that.
Sometimes, in a temporary cloudless situation I tape PZM mics or just small omnis, DPA4061, to the ceiling or wall behind the kit. No reflection issues.

The Chequerboard is how the BBC did things. They found it possible to achieve a reasonably diffuse sound field using absorption alone.

Space Couplers or DIY equivalent under the cloud are a very nice extra touch, say over the kit.

DD
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Quote:
Originally Posted by DanDan View Post
Aaron, I have grown to think in Fours.
Four inch traps, hung with a four inch airgap. A decent number of those will have a go at the 70Hz Height mode and more importantly it's multiples.
Four of them over the kit. Four over the vocalist. Just for starters.
A 50Hz Null could well be SBIR. Close miced drums will not experience that.
Sometimes, in a temporary cloudless situation I tape PZM mics or just small omnis, DPA4061, to the ceiling or wall behind the kit. No reflection issues.

The Chequerboard is how the BBC did things. They found it possible to achieve a reasonably diffuse sound field using absorption alone.

Space Couplers or DIY equivalent under the cloud are a very nice extra touch, say over the kit.

DD
Would you even suggest a 4" thick absorber w/ 4" gap in a room with 8' ceilings? I've seen space couplers in studio pictures online. What would be the benefit of a coupler versus a 3D QRD diffuser? Thanks for the good advice!
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Quote:
Originally Posted by Rod Gervais View Post
The cloud could always be hung using a temporary device - a freestanding frame made from PVC or aluminum tubing.

The purpose of the cloud is a avoid early reflections from above - you don't need early reflections from above getting back into those mics. This assumes (of course) that the room has not been designed to handle those reflections in another manner.

Rod
So on 20' vaulted ceilings you wouldn't put a cloud above the drums.?
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Aaron, I stick with my recommendation. Too much detail to go into here but the thick cloud reigns supreme to my ear. Space Couplers are expensive, so a bit of luxury unless you go DIY. Check out TornadoeTed at GiantWafer. He built and I trust is building beautiful bamboo Space Couplers. Speaking as a recording engineer, I love them. Always welcome at the party, no harm possible.
DD
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Quote:
Originally Posted by GreenNeedle View Post
So on 20' vaulted ceilings you wouldn't put a cloud above the drums.?
I would if the reflections were problematic....

When I design rooms (as opposed to being brought on board to design treatments for existing spaces) I always design them taking into account early reflections from above - however existing spaces might be problematic even with high ceilings.

This (however) is also quite apparent from the onset.

Rod
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