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I Hit My Competence Ceiling
Old 13th April 2019
  #1
Here for the gear
I Hit My Competence Ceiling

There - I said it. I feel better. I've been turning a disaster of a home project studio situation into something that is starting to sound decent. I've never been able to internalize just how bad of a monitoring and tracking situation I really had until I got better at everything else. Then I did a song and it came no where as good as it should have been. Countless remixes later and I came to the conclusion my room was horrible. I was right. Just awful.

A very busy month that included things like getting rid of a huge desk hutch, removing and re-attaching studio foam, better monitoring and positioning, etc, etc. It has come a long way in a short time. It is so much better, and that is without dealing with the room mode or ceiling treatments. Heck, proper wall treatments are surely to be suggested. BUT, I did have to get this room to the point where it is before I could see the light. And here is where I am.

- Monitors are as close to the front wall and as well placed from side to side, angled and height as I could get them to sound good and as complete as possible given room constraints.

- I have to put my last bit of foam up on the ceiling for now until I get the proper treatment. (which I hope y'all will steer me towards)

- A HUGE part of the problem in here for tracking is/was slapback-echo-flutter. It is tons better just repositioning foam, and that is with untouched ceiling. I will but my last few square feet up there this weekend until I get a better solution.

- Room is rectangle with a closet that is built out into the room for 3/4 of it's width. If I include the closet, it is 4m (L) X 3.2m (W) X 2.4m (H). If I take the closet out of the dimension, 3/4 of the room is 3.4m (L) X 3.2m (W) X 2.4m (H). When examining the REW readings, sometimes it behaves like it's 4m long. (42-44Hz mode?) Other times it acts like it's shorter. (biggest low-mid ring is 134Hz and another big mid-boost at 464Hz)

- Nice big double window on long wall.
- Nice big 6-lane highway is the closest thing to the back of my house. Trucks can make for rumbles. Lovely.
- More? Sure. Add an airport that has landing zones 2 streets over in each direction. Don't feel too badly for me though, because....
- The rock quarry blasts 2 miles away only happen once a day and sometimes don't even shake the house.
- Oh, my desk is fairly cheap and fairly closed. Solid particle board sides and privacy panel at front. It's least disruptive shoved way up almost to the front wall.
- Monitors are on mopads, on separate small sized 1X1 sq ft, 4 feet high book cases made from particle board.These boards rumble big time, but not audibly so, when any volume is going through them. The monitors sit on TOP of these cases. Should I get real monitor stands?

And so now for the REW. I've seen the arguments about where to point the mic. I've tried at the monitor, at the ceiling and tilted part way up the front center wall. Not a whole lot changes, so most of my testing and moving has been with the last option. I did do the Soundcard calibration using my UAD Apollo 6x, but it's functionally inaccurate as the levels change depending on which port is being used as the input and I don't have a cable for the job. I will get one if it matters, but I see most say it does not. I do have the Dayton mic on the REW site and have downloaded the cal file and gone through all the rest of the calibrations.

The REW decay times are short on the upper ends and long at some points on the low end. Looks like a lot of room mode from what I can see. There is a lot of distortion down below 100Hz, too. I can easily find the offending spots in my room with the sine generator and the SPL meter. I did 134Hz and found hot spots way up top center wall as well as corners. The 465Hz was all over the place and changed quickly. Lower tones below 100Hz were as one would predict after seeing my waterfall charts.

So, as long as everyone is cool with mic position and volumes measured, I'll get better mdats this weekend and do L. R and L+R as the links implore me to do. I really wanted a sanity check before going too much further just to make sure I am on a decent path.

What I THINK I need to do is get some sort of flexible or maybe even tuned low frequency bass traps like what GIK or some others sell for the front corners. The back corners are going to be really tricky if not impossible to do much with. Maybe one of them. I'm pretty sure I will need to get-build a cloud for above the desk and at the ceiling to wall joint. also one above me. I've got no prob;em phasing out the wall foam as needed. The quick decays might ale I would prefer not at once. This has been a VERY expensive 10+ months between some fine acoustics amd studio gear.

So, whatcya think? Am I even close? Right track? Got any directions to take?
Attached Thumbnails
I Hit My Competence Ceiling-4-10-one-sample-waterfall.jpg   I Hit My Competence Ceiling-4-10-one-sample.jpg  
Attached Files
File Type: mdat 4-10 one sample.mdat (1.84 MB, 25 views)
Old 13th April 2019
  #2
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Temple of Light's Avatar
 

This image saved my ass countless times, and countless dollars...
The one just below "Acoustical room Advice"

Acoustical Room Advice - GIK Acoustics

YYMV

Light

Temple
Old 14th April 2019
  #3
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I've been staring at your REW data, and trying hard to figure out how the hell you managed to do that! What I mean is, your phase angle INCREASES with frequency, instead of decreasing. What does that mean? It means that time is probably going backwards in your room! So congratulations on inventing time travel!

But seeing that time travel is impossible, it's probably more likely that there's something wrong with your testing...

Let me explain: Below are two frequent response graphs with the phase overlaid: the red one shows your results, the blue one shows normal results. In each case you can see the frequency curve in a darker shade, and the phase response graph superimposed over it in a brighter shade.

Phase angle should only decrease with frequency (unless there's a strong reflection or other issue causing a phase glitch in a specific narrow frequency band)... but in your case it is increasing with frequency, which sort of implies that it is happening earlier in time.... and that's hard to explain. That implies a negative time delay... In other words, sound is alread moving around the room BEFORE it leaves the speaker....

Probably for the same reason, your Impulse Response (IR) graphs looks very strange, and gives impossible results: The second two graphs show your IR (red) and a more normal IR (blue). What that shows is how your room reacts to a sudden, infinitely short and infinitely loud sound (think: gunshot). As you'd expect, in a normal room, the impulse is really large, then sound bounces around the room all over the place, slowly dying away to nothing. Each vertical line on an IR graphs represents one specific reflection that came back to the mic after the original impluse, and as you can see, mostly they get lower and lower in level. But in YOUR case, the reflections get inexplicably LOUDER in level as time passes! Your impulse at time =0 is 10 dB lower than the one at about 18ms later, which in turn is 10 dB lower than the reflection that occurs at 40 ms.... only then does the level start decaying.... It's really hard to explain how sound can amplify itself of its own accord as it moves around the room Especially considering that, in theory, the impulse itself was already infinitely loud... but somehow it manged to get even louder than infinite...

That's why you also get impossible results in the analysis: your early decay time is LONGER than your later decay times....! Look at the data panel on the left: REW figures that your very earliest reflections (EDT) arrive 887 ms after the impulse, but then the next bunch of quieter ones (T20) arrive about 363 ms after the impulse... and if you measure for a longer period, to get the even lower level levels (T30), well, now the reflections arrive earlier still, at 242 ms... That can't happen in real life, of course... unless time is traveling backwards in your room! Or your measurement is messed up.

In fact, I would take a guess and say that the actual impulse is the one at 40ms, not the one at 0 ms, and the ones before 40ms are either noises you made in the room right before you did the test, or they are glitches caused by somthing amiss in your system, or your testing.

So, it would seem that there's some type of timing issue with your setup, but I have no idea where to look, or how to fix it.

Conclusion: Your results are nor trustworthy... with major issues like that, even though some of the data looks believable, the rest of it doesn't, so I would not trust any of it.

I'd suggest that you repeat the setup and tests very carefully, following this procedure: John Sayers' Recording Studio Design Forum •

View topic - How to use REW to analyze the acoustics of your room...
.

(Oh, yeah, and please make sure your clock and calendar are running FORWARDS for the next test.... )

- Stuart -
Attached Thumbnails
I Hit My Competence Ceiling-rew-phase-increasing-strange.png   I Hit My Competence Ceiling-rew-phase-decreasing-normal.png   I Hit My Competence Ceiling-rew-phase-decreasing-normal-ir.png   I Hit My Competence Ceiling-rew-phase-increasing-strange-ir.png  
Old 14th April 2019
  #4
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akebrake's Avatar
 

Bug or sample rate?

Quote:
Originally Posted by rparker View Post
...
So, whatcya think? Am I even close? Right track? Got any directions to take?
Me thinks you have to make a valid measurement first...

A correct impulse should have one clean spike in the beginning.

1. Try downloading the latest REW version.
REW 5.20 beta 8 was released two days ago.
Continuously improved and with new features added.

2. Is the sample rate OK for your Dayton? 48kHz?

Good Luck
Attached Thumbnails
I Hit My Competence Ceiling-info.jpg  
Old 14th April 2019
  #5
Here for the gear
Thanks Soundman2020. I agree. Not only does some of the data look plausible, it matches up with the dimensions and predicted modes. It also matches up with what I hear and what I can detect with SPL meter and sine wave generation, walking around, etc. I might even call it eerily spot on when comparing the 3D model on the amroc room mode page and the REW room functionalities. That also matched up back to doing things like moving mic and monitor.

However, beyond some of the very basic information in my REW readings, the charts and graphs begin to look all kinds of wonky. I would have no reason to doubt that the tests are messed up somehow, or that the room had some serious defect with external noises getting into it. (I described above the highway, airport and very active neighborhood kids playing ball in my cul-de-sac. That's all on top of an aggressive HVAC fan and other household noises. The biggest thing might very well be the highway rumbling of cars and trucks. Especially trucks with knobby tires. It will never be pristine, but it can be better.

I did RTFM as well as the stickies in this forum as well as the how-to video posted by the respected user whom I now forget the name of. I've gone through the set up and calibration thing. I set a 10 second pre-test timer and leave the room. The thought did occur to me that I do have an older mbox3 interface at my disposal. I can try that for these tests if the "soundcard" calibration using the feed-back system is that important. I've read and seen all over the place that it isn't, including the main sticky on this forum.

Regardless of everything talked about, I'll look at your site and see if anything different pops out and do another set of calibrations either way.

Thansk for the response and I'll post what happens after I go through it this afternoon.
Old 14th April 2019
  #6
Here for the gear
Quote:
Originally Posted by akebrake View Post
Me thinks you have to make a valid measurement first...

A correct impulse should have one clean spike in the beginning.

1. Try downloading the latest REW version.
REW 5.20 beta 8 was released two days ago.
Continuously improved and with new features added.

2. Is the sample rate OK for your Dayton? 48kHz?

Good Luck
I've got 5.2 beta 8 on laptop just the other day, but not on my music machine yet. I'll do before proceeding.

The Dayton mic is analog and goes through my UAD interface. 48kHz should not be a factor at all.

Anyhow, I'll go through the process as I jsut described to Soundman2020 above and go from there. I'll even change interfaces if I have to for these tests.

Thanks for your response and looking at my situation.
Old 14th April 2019
  #7
Here for the gear
Alrighty, then. I spent a couple of hours trying various configs between Windows WDM and UAD Apollo X-Series worlds as well as recalibrating to increased levels to 80db on the SPL meter. The results were inconsistent as one could imagine. Maybe 1 in 8 did not have flaky IR results. The last straw was the loudest plane of the day coming into the airport of the day not making a dent. UAD does have some latency and delay compensation that it manages, and one never knows when Windows and ANY interface is gonna start mis-directing traffic.

So I set up an old interface, - an mBox3, and spent some time getting it set up and working right, hooking monitors and mic, etc. All of the tests seemed to look more plausible as far as no time travel is concerned. I even installed the newer version and tried it again. The distortion chart also looked more reasonable as far as possible is concerned.

I wish I had gone and done a L, R and L&R series. I can do that later on today or tomorrow. I was more in the making sure I was getting valid tests mode than anything. I think most of my initial analogies hold water, but not sure enough to take any action.

Whatchyu folks think?
Attached Thumbnails
I Hit My Competence Ceiling-4-14-ir.jpg   I Hit My Competence Ceiling-4-14-freq.jpg   I Hit My Competence Ceiling-4-14-waterfall.jpg  
Attached Files
File Type: mdat 4-14 mBox3 tests.mdat (5.90 MB, 9 views)
Old 15th April 2019
  #8
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Welcome back, Marty McFly! Glad you managed to ditch the Delorean!

The good news is, your data is valid, and meaningful, and makes sense. Your time travels are over. I guess it would have been nice to figure out what was causing that (I'm intrigued!), but at least you have a good way of measuring now.

Quote:
All of the tests seemed to look more plausible as far as no time travel is concerned. I even installed the newer version and tried it again. The distortion chart also looked more reasonable as far as possible is concerned.
All looking good there!

The bad news is that your studio is very noisy! I think you already knew that, but it's clear from the new data that your room is not isolated, and there's lots of loud, low frequency stuff going on around you. That doesn't bode well for being able to track in the room, or for being able to mix consistently any time you want.

The other good news is that your actual acoustic response doesn't look too bad: The overall decay times are reasonable, except in the low end: you could use more bass trapping, probably. Modal stuff appears to be under control, but it's hard to be certain due to the low frequency noise. Your 80 Hz dip might be SBIR, but once again it's hard to say. The separate L and R measurements MIGHT help identify that, but probably not. The simplest way of dealing with it is probably to add a sub to your system, and set it up to cancel out that dip. You could also perhaps o searching for the culprit, and maybe move stuff around in your room, or add even more treatment, but frankly a sub is simpler and faster.

OK, the BIGGEST issue is that you seem to have a very, very strong reflection coming in very, early (less that 1 ms after the direct sound) on one of your measurements, which might have been what we were seeing yesterday too, .... but it isn't there in the other two! Which makes me suspect that it is not acoustic... But you also do have a couple of other reflections that could do with treatment. In the image below you can see those: any peak above 10% could definitely do with treating, and it would be better to go for everything above 5%. The really early ones at 20% and 35% are nasty... Those must be coming off surfaces very near to the speaker or the mic, since the reflation path (=time delay) is very short. Just a few inches longer than the direct path.

To give you more intelligent advice, we would need to see an accurate diagram of the room, and some photos. We might be able to help you figure this out much better, if you can show is what you are dealing with...

- Stuart -
Attached Thumbnails
I Hit My Competence Ceiling-rparker-rew-ir-reflections.png  
Old 15th April 2019
  #9
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robert82's Avatar
My two cents:

You're very busy making measurements of the same thing: a room treated with foam. If I wuz u I would just put as much 703, or Rockwool panels in the room (especially corners) as possible, THEN measure. I think you'd be pleasantly surprised.
Old 15th April 2019
  #10
Here for the gear
Quote:
Originally Posted by Soundman2020 View Post
Welcome back, Marty McFly! Glad you managed to ditch the Delorean!

The good news is, your data is valid, and meaningful, and makes sense. Your time travels are over. I guess it would have been nice to figure out what was causing that (I'm intrigued!), but at least you have a good way of measuring now.

All looking good there!

The bad news is that your studio is very noisy! I think you already knew that, but it's clear from the new data that your room is not isolated, and there's lots of loud, low frequency stuff going on around you. That doesn't bode well for being able to track in the room, or for being able to mix consistently any time you want.

The other good news is that your actual acoustic response doesn't look too bad: The overall decay times are reasonable, except in the low end: you could use more bass trapping, probably. Modal stuff appears to be under control, but it's hard to be certain due to the low frequency noise. Your 80 Hz dip might be SBIR, but once again it's hard to say. The separate L and R measurements MIGHT help identify that, but probably not. The simplest way of dealing with it is probably to add a sub to your system, and set it up to cancel out that dip. You could also perhaps o searching for the culprit, and maybe move stuff around in your room, or add even more treatment, but frankly a sub is simpler and faster.

OK, the BIGGEST issue is that you seem to have a very, very strong reflection coming in very, early (less that 1 ms after the direct sound) on one of your measurements, which might have been what we were seeing yesterday too, .... but it isn't there in the other two! Which makes me suspect that it is not acoustic... But you also do have a couple of other reflections that could do with treatment. In the image below you can see those: any peak above 10% could definitely do with treating, and it would be better to go for everything above 5%. The really early ones at 20% and 35% are nasty... Those must be coming off surfaces very near to the speaker or the mic, since the reflation path (=time delay) is very short. Just a few inches longer than the direct path.

To give you more intelligent advice, we would need to see an accurate diagram of the room, and some photos. We might be able to help you figure this out much better, if you can show is what you are dealing with...

- Stuart -
Thanks for looking and putting some thought into this. I apreciate this a lot.

Yes, this is a very loud room for what I do. I can only imagine how awful a chart would have looked a month ago. Imagine a room with this bad of a low end and having the slapback and flutters be the worst of the evils. Almost scary. I wish I had looked at this forum like 2-3 years ago. But here we are.

I'm kind of lost on where to begin looking for those early reflections. Are we talking like maybe with a few feet of the monitors, or the mic?

Anyways, I will get:
#1 : A nice diagram going from the GKL site
#2 : Current real-life pics.
#3 : I also do want to move a bit of the existing foam around to the ceiling.
#4 : Take a L-R-LR measurements.

Would it help to take a REW measurement or two with the Monitors in a couple different positions? 8 inches away from from wall and another 6 inches towards side wall? Just thinking ahead for helping to isolate modal from SBIR.

I have to take a day to get this as today has too much real life going on to play with my room. Tax-day here in the US, and also our(me and the misses) 30th anniversary today. Good times!

standard foam disclaimer for anyone looking - foam bought before I knew better and some gifted, but has at least helped in proof of concepts such as when used to control the decay, slap-back and flutter echos.
Old 15th April 2019
  #11
Here for the gear
Quote:
Originally Posted by robert82 View Post
My two cents:

You're very busy making measurements of the same thing: a room treated with foam. If I wuz u I would just put as much 703, or Rockwool panels in the room (especially corners) as possible, THEN measure. I think you'd be pleasantly surprised.
Learning and fixing my ruler first and proving some concepts along the way. Informed decisions are better for me even if derive at the same outcome. (confidence factor in the very least.) Also - see standard foam disclaimer at the end of previous post. While doing nothing for low end, it's helped me prove issues with mids and highs to massive extents. It will come down for better as time, budget and priorities allow.

As many say here - cheers!
Old 16th April 2019
  #12
Here for the gear
I think I have all of the pictures and mdat information requested.

Foam disclaimer. It's what I had on hand already and is doing some good. Obviously not good enough, which is why I am here. I did add the last bit of foam I had to the ceiling this morning.

Edit: The pics did not get displayed in order. The "way before" pic is the older shot from before getting started on fixing audio.

pic #1 : The room as it was up until a couple of months ago. This feels like an embarassing confession. The audio in this room has improved a ton just by getting rid of that hutch and getting some half-decent monitors.

Next 4 pics are of the room as taken a few hours ago. Please pardon the clutter. The image names contain vantage point abbreviations. The dimensions are somewhat skewed by the inwards facing closet. 3.44M (or 4M) long X 3.17M wide X 2.44M height

Note that out of the frame is a big ceiling fan that I discovered is ringing out a tiny bit when I do a hand-clap test. It's a goner this weekend.

3 REW images from today's test and a GIK room diagram I did up.

Last up, I hope, is the Left, Right and L+R mdat file.

I don't think there are many surprises. My plan of attack at this point is to get:
#1 : Some bass traps for the corners to tame some of that rumble. Just not sure which ones to get. (just bass, or broader band, etc - probably choices on the GIK site unless better suggestions arise.

#2 : A cloud(?) for above my head. Not sure which.

#3 : Some sort of bass trap(?) on the front wall/ceiling intersection. The 134Hz generated tone was pretty strong up there.

#4 : This might be for the next round, but I bet I will need to do something to the rear corners at some point. For now, perhaps, I can re-use that stuff that is currently in the front corners. (it was a gift, but she won't be upset if I cannot use....)

I do have lots of foam up already and can use to augment. Not show, I think, are two 2' X 2' X 2" aurelex pads that I've had a while. I hope to incorporate those into the plan if I can.

That's it. If the plan of attack sounds good, I will need pointers on what to get. If the plan of attack is not good, please let me know what adjustments I need to make.

Thanks!!!
Attached Thumbnails
I Hit My Competence Ceiling-front-r-rear-small.jpg   I Hit My Competence Ceiling-left-rear-small.jpg   I Hit My Competence Ceiling-rear-lf-corner-small.jpg   I Hit My Competence Ceiling-right-rear-sm.jpg   I Hit My Competence Ceiling-way-before_sm.jpg  

I Hit My Competence Ceiling-4-16-freq.jpg   I Hit My Competence Ceiling-4-16-left-ir.jpg   I Hit My Competence Ceiling-4-16-left-wfall.jpg  
Attached Files
File Type: mdat 4-16 GS Upload.mdat (5.90 MB, 6 views)
Old 16th April 2019
  #13
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robert82's Avatar
Here's where I'm having a problem with your approach. You are doing measurements that befit the design requirements of a very expensive room, but from the pictures you posted, there isn't even a 10th of the broadband and bass absorption you will actually need to get in the ballpark. All you really have is some treatment of flutter echo.

So, again, my .02 is to reverse your priorities: Add serious bass trapping, and thick (THICK) broadband absorption all over the room (and yes, a cloud - a thick cloud) . . . . . . THEN start doing measurements.
Old 17th April 2019
  #14
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Robert is absolutely right. What you have there right now is basically several pieces of very thin foam, checker-boarded around the room: At best, it is controlling some flutter echo in the high mids, and bringing down your high-end decay times. I haven't even looked at your MDAT data yet, but that's what I'm predicting based on the photos.... Standby while I check your latest data....

(time passes....)


Yup, pretty much what I suspected. As I mentioned before, you do have modal issues that need treating, and those are the hardest to hit. Most of your low end is not too bad (as I also said before), but there's room for improvement, that's for sure. Bass trapping is what you need.

However, the high end is deader than I expected, and the culprit is clear from your photos: carpet! Your floor is carpeted! That has to go. Carpet is the enemy of good control-room acoustics. It does pretty much the exact opposite of what small rooms need. So, in addition to getting rid of the foam, you also need to get rid of the carpet, then there's a whole list of other things that you'll also need to do, to get your room usable:

- Ditch ALL of the clutter! Get absolutely everything out of the room, except the desk, chair and speakers. It all needs to go, including the book shelf near the door, and your rack of guitars, the floor lamps, various bits and pieces. Everything. Empty out the room completely, to leave ONLY what is absolutely needed for a control room, and nothing else. You can't properly test a room that is full of stuff that doesn't belong there.

- Get rid of those boxy things that your speakers are sitting on, and invest in some proper speaker stands: massively heavy ones that are adjustable in height, or maybe fixed height but with the correct dimensions to get your speakers raised such that the acoustic axis is 120cm above the floor. That's the "standard" height for speakers. Note: "acoustic axis"! That's what has to be 120cm above the floor. Not the top of bottom of the box, nor the woofer, nor the tweeter (often incorrectly given as the location of the acoustic axis), but rather the ACTUAL acoustic axis. Contact the manufacturer to find out where that is. Set the speakers directly on top of the stands, without the foam wedges under them. The speakers should be set up flat on the stands, not aiming either up or down. The stands need to go tight up against the front wall, with a separation of only 10cm between the rear corner of your speaker and the wall, where you will insert an absorption panel that is 10cm thick. Each speaker should be about 30% of the room width, away from its wall. In other words 3.2 x 30% = 96cm from the side walls The speakers will thus be about 128cm apart (once again, measure to acoustic axis, not the sides of the box). This isn't the final setup: just a starting point.

- Pull the desk away from the front wall: it's too close.

- Set up your chair exactly centered in the room (side to side), such that your ears will be about 140 cm from the front wall when you are mixing normally. Set up a vertical pole of some type about 40cm behind your head (in other words, about 180cm from the front wall). That pole must also be on the center line. Rotate each speaker on top of it's stand such that the acoustic axis points exactly at that pole (a laser pointer resting on top of the speaker is an easy way to do that), while taking care not to mess up the other measurements you already did (distance to side wall and front wall).

- Now set up the desk in front of the chair so it is at a comfortable location for you to operate your gear, and is also carefully centered in the room (left to right)

- This is the correct basic initial layout to get you started. It can probably be improved later, after you get the initial treatment in place, but it's a good layout to get started. Don't worry about the infamous "equilateral triangle" that everyone will try to convince you to use for your speakers and head: it's a myth that you have to set up your speakers and head like that: there's no good psycho-acoustic reason to do so.

- Now, with that setup completed, do a proper REW test, which will be your "Baseline" for measuring all future tests against.

- Initial treatment comes next: Take off the closet doors, empty out the closet, and fill it completely with light weight building insulation, such as fiberglass or mineral wool. That's going to be a darned good bass trap and rear wall treatment You are very lucky to have that: make the most of it.

- In addition to that, put a "superchunk" style bass trap in that corner between the closet and the wall, as well as another superchunk horizontally in the corner between the ceiling and the wall above the closet, plus a smaller one in the same corner above the alcove where the door opens. You will probably need to face some parts of those superchunks and the closet bass trap with plastic sheeting, above and below ear height, to avoid over-absorbing the high frequencies and the high-mids. Cover with nice fabric of your choice, to make it all look nice.

- Do another pair of superchunks in the front vertical corners of the room, and across the front wall/ceiling corner. Once again, cover them partially with plastic sheeting above and below ear height if they end up "sucking out" too much of the high end.

- Put thick absorption panels on the side walls at the first reflection points, made from 15cm thick mineral wool or fiberglass.

- Hang a "ceiling cloud" from the ceiling between the mix position and the speakers, built the same way. Make it big.

OK, that's the rough initial layout and treatment that will get your room usable. Take care to do it accurately, because symmetry is very important. You don't have symmetry right now: your left and right speakers have different response, which is why you don't have a clear phantom center, nor an accurate sound stage.

Do all that, and you should have a very usable, fairly smooth, clean acoustic response. It still won't be flat in frequency response, but it will be considerably better.

Do the REW tests on that, upload them here, and we'll help you analyze those too.

- Stuart -
Old 17th April 2019
  #15
Here for the gear
Thank you for your time.
Old 3 weeks ago
  #16
Here for the gear
OK, so 7 months later and the budget is in place to start doing this stuff.

With regards to below, I think the biggest question I have is the amount of actual wall and ceiling space being covered is almost 40%. I'm adding space and air back in post production after deadening the room and before adding diffusion. Is th3 39'9% coverage including soffitt bass trap coverage too much? Should I even count the amount of wall space used as bass trapping towards that overall percentage covered number?

And here where I am:

I did some of the cheaper things right away. Speaker stands, no foam monitor pads and replaced and moved desk & chair. Monitor positioning going way out to the corners, though, proved to be very nice. I didn't work with the desk closer to the wall first time I tried it.

Fast forward 6 months and I bough some ill-conceived and constructed bass traps. Aside from cheap finished appearance, the kid (20-something) stuff 12-inches of foam into an 8-inch frame. Yeah, I know. I am going to re-use materials, though, so not a total loss.

I was able to test the room as advised by placing two of the three 24"x84"x8" monstrosities in the front corners and one on the back wall behind me. Nice improvement with modal ringing and some of the reflections. Bass performance as limited for obvious reasons, but the 200Hz to 750Hz range was alread much better.

I then tested them as gobos. Dramatic improvement on tracking vocals and decent improvement on tracking an acoustic guitar. Good enough to know that I will be able to use this small room once things are done.

The biggest thing I learned was that I am getting some HUGE, nasty thick and bright early reflections into anything I track and have tracked. I had no idea how bad they actually are. Lesson learned.

Also note that I did as advised last Spring and contracted GIK. With the constraints of the budget at the time considered, I was advised to go with:
- two 24"x48" 244 first reflection panels
- two 24"x48" Monster bass traps behind monitors
- two soffit traps in front corners
- Temporarily layering of my foam to the ceiling.

Phase #1
OK, so at this point, I am giving very strong consideration to getting the most for my money and going DIY. On the over-kill list is:
#1 Make 4 soffits for front corners. Ceiling to floor, 47" each
#2 Two 4" bass traps 24" x 48" for first reflections
#3 Two 6" bass traps for behind Monitors.
#4 One soffit or Monster top center of front wall.
#5 One 8" to12" 24"x36" monster trap above entrance on ceiling.
#6 4 clouds on ceilings 24"x48"x4"
#7 Two attached 24"x60"x4" on stands for left wall in front of window
#8 Two attached 24"x60"x4" on stands for right wall in front of window
#9 Three 16" x 48" x 6" bass traps on rear wall.
#1 0: TBD on additional ceiling to wall bass traps.

Notes:
- Hoping to score some Rockboard RHT40, Knauf Ecose 1.6lb rigid 2nd choice and OC703 3rd. 4" and 6" will be layered 2". I can use a couple layers of Safe n sound if I had to resort. I know it's preferred acoustically, but do not want the hassle of un-rigid.
- The soffits will be constructed using 2" rigid top,bottom and 2-4 sides with the 12" fluffy I already have.
- This is 39% ceiling and wall space, including window coverage and including the amount of space being covered by the 5 soffit traps. (11.5% on their own)
- Note that I have some fairly decent plugins to use to add space back into recordings and mixes that I do/will not get automatically if I had a decent room.
- Optional - Thinking of getting 1 or 2 cases of the 705FRK to use as needed for the front of some of these to add some reflection back in.
- Optional - Alternative to the foil front as needed, I was thinking of adding a phase #2 , which would be to take my then dead room and add diffusion/reflection to give it some air / space.
- No carpet removal for now. A couple moving parts in play.
- Same for the idea of fluffy in the closet. If my efforts are not good enough and if the moving parts settle in a manner favorable to doing so, I will do this.
- A am hoping that some of the soffit use will help absorb low end rumbles from exterior sources.
- At some point, I will get use of our not so big bonus toom, which is 12' x 18'. I thought that point would be here by now. Alas...
- Lastly,
Old 3 weeks ago
  #17
Lives for gear
 
Jens Eklund's Avatar
You might find this thread useful:

Advice Wanted: Best Option(s) for Additional Bass-Trapping
Old 2 weeks ago
  #18
Here for the gear
All the materials for the 1st phase of my studio-room acoustic treatment project is here save a couple small items. 3-inch (x2) Safe and Sound (SnS) and 12-inch fluffy pink(FP) as marked. It might look like overkill in spots, but I am in a very noisy location. I do like the idea of starting from a more deadened space due to this. Also due to this, there was no way that even a doubled budget was going to cover this unless I go DIY. Fortunately, my Son is more than able and digs this kind of thing. Yay for me!!!

One question I'm putting here instead of buried later: Regarding the plastic lining suggested here and on other threads for some possible reflection sections when building panels/traps. Is this just normal plastic sheets like someone might use to protect the floor during a painting project? Just normal wicked cheap plastic?

OK - The highlights:
  • 4 - 18" x 18" x 48" bass traps in front corners - stacked. (FP or both)
  • 2 - 30" x 72" x 7-1/4" bass traps front wall (can be bigger) (SnS)
  • 6 - 24" x 72" x 7-1/4" bass traps side walls. (SnS)
  • 1 - 24" x 72" x 7-1/4" bass trap directly behind desk (SnS)
  • 1 - 24" x 36" x 12" cloud(super chunk?) above entrance. (FP - I think)
  • 5 - 12" x 12" x 40" triangle traps 2 each side wall - ceiling, 1 rear (SnS)
  • 1 - 15" x 15" x 48" triangle front center wall at ceiling. (SnS)
  • 4 - 24" x 30" x 7-1/4" clouds (SnS)
  • Rear room closet cleared out, doors removed and 24" ins floor to ceiling.

I'm hoping the 125" x 134" room will effectively become a 125" x 162" rectangle room, which will fit in the "bolt" area.

The obsessive nature of the thicker panels is all in an effort to reduce the extra rumble as described due to the location.

The 6 side-wall, 2 front wall and the 1 rear wall panels are all going to be gobo panels for portability. The only things not easily moveable easily will be ceiling to wall triangles, clouds and the closet full of insulation.

Phase-2 - diffusion
The only thing I did not get yet is the plastic to put inside of the fabric in suggested spots. Phase-2 will be all about diffusion & reflection, and I can start building right away. The gobo panel designs will be all solid-wood sides and equal 24" x 24" squares in case I want to try and get cute with just one section and perhaps try a limp membrane (and adding rear plywood) or something else yet to be determined. I do already have eight 24" x 24" square peg-board panels for possible use to add a bit of reflection as needed. I'm thinking of wrapping in fabric and making them detachable add-ons depending on the activity. (velcro, hooks, tbd) Perhaps even adding actual purpose made diffusors in a similar manner.
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