John Sayers' Design Forum

John Sayers' Recording Studio Design Forum

A World of Experience
Click Here for Information on John's Services
It is currently Thu May 23, 2019 8:31 pm

All times are UTC + 10 hours




Post new topic Reply to topic  [ 34 posts ]  Go to page Previous  1, 2, 3
Author Message
PostPosted: Fri Jan 25, 2019 12:17 pm 
Offline

Joined: Tue Mar 24, 2015 10:42 am
Posts: 22
Location: Southern Oklahoma USA
Okay so curiosity got to this cat, and I decided to do some more measurements. This time with my ULN-2 and Macbook pro. The levels are a bit higher. And from what I can tell seem to be in about the range they're suppose to be. Let me know. So maybe my other interface (a scarlett 6i6 v2) is doing something weird level wise. For kicks I got out an LDC (CAD M179) and did one measurement with it. That huge hole in the lows (from around 88hz to 130hz) had me wondering if maybe my mic was broken. I didn't save that measurement, because according to the SPL graph, the hole is very real. I was actually quite surprised how close both graphs were considering the difference in mics. So it's definitely the room. I also compared me newest measurements to the ones in the previous comment and from what I can tell they are very very close. At least to this untrained eye. So I feel my results are at least moderately reproducible. Again chime in if I'm obviously doing something wrong and my measurements aren't as close as I think.

Anyway back to "The Hole" I know this probably can't be eliminated with my limitations of how much treatment I'm willing to install, and because of the room itself. However I'm wondering if moving the speakers and/or listening position could help? I've read an inch or two can make a big difference. Aside from that is trapping the corners my biggest bet at reducing it? Because man is that the grand canyon or what? I did try and compare to some of my earlier measurements. From what I can decipher, things are improving. And by that I mean the difference between the lowest level and the highest level has decreased some. And I only have the front 2 corners about 2/3 full. So I guess I kind of answered my question to a degree. I need much more corner treatment. I'm just curious as to estimations about how much better it might get?

Here are the newest measurements

As always thanks in advance.


Report this post
Top
 Profile  
 
PostPosted: Fri Jan 25, 2019 1:41 pm 
Offline
Site Admin
User avatar

Joined: Thu Aug 21, 2008 10:17 am
Posts: 11880
Location: Santiago, Chile
Quote:
I'm not seeing that much difference from my earlier tests,
:shock: :?: Are we looking at the same tests? :) Hint: do not look at the frequency response graphs! Contrary to popular belief, they are NOT the most important information that REW is giving you! Don't get hung up on the wrong goals...

So, let's take a look at how things have changed. I prepared a bunch of graphs of various aspects, with three graphs in each set. The first one in each set is the "baseline" test from the empty room, the second one is from the "re-measured" data, and the third one is from the "superchunks plus first reflection points" data from yesterday (not the new stuff from today: no time to look at that).

First, seeing that you like the Frequency Response graphs so much (even though they are not the key to how well a studio performs...), let's start with that: In this case, I put all three on the same graph, to make comparison easy.

Attachment:
MattE--REW--FR--20-820--all-three-L.png

That's just for the most important part of the spectrum: the bottom half. In this case, 20 Hz to 800 Hz, aprox. It sort of looks like there are some major differences in there! :)

Next up, the RT-60 graphs, showing he decay times across the spectrum, in 1/3 octave bands:


BASELINE:
Attachment:
MattE--REW--RT--45-12k--Baseline-L.png



REMEASURED:
Attachment:
MattE--REW--RT--45-12k--Remeasured-L.png




SUPERCHUNKS + FRP:
Attachment:
MattE--REW--RT--45-12k--Superchunks+FRP--L.png



HUUUUGE differences there. The baseline was off the charts. The room right now is well within specs for decay times. Your goal is around 200 ms, +/- 50ms. You'll have to be careful from here on to not overdo the high frequency absorption, or you'll make the room too dead.



Now for the Spectrograms:


BASELINE:
Attachment:
MattE--REW--SP--20-820--Baseline--L.png



REMEASURED:
Attachment:
MattE--REW--SP--20-820--Remeasured--L.png



SUPERCHUNKS + FRP:
Attachment:
MattE--REW--SP--20-820--Superchunks+FRP--L.png



No comment necessary! The major, enormous, huge, big-time differences are self evident. The "remeasured" one shows some pretty serious phase issues, all over the place... they are mostly gone in the latest one.



How about the waterfalls?

BASELINE:
Attachment:
MattE--REW--WF--20-820--Baseline--L.png



REMEASURED:
Attachment:
MattE--REW--WF--20-820--Remeasured--L.png



SUPERCHUNKS + FRP:
Attachment:
MattE--REW--WF--20-820--Superchunks+FRP--L.png


Once again, the massive improvements are self evident.

The last one is showing that you seem to have a noise issue: those spikes at the bottom might not be related to acoustic issues in the room: There is some modal stuff there, yes, but I suspect there might also be some noise getting into your room from outside, or from gear, or from HVAC... Not 100% certain, but it looks like it might be the case. It might also be flutter echo, or something similar....


And finally the most important graph of all: Impulse response:

BASELINE:
Attachment:
MattE--REW--IR--180ms--Baseline-L.png



REMEASURED:
Attachment:
MattE--REW--IR--180ms--Remeasured-L.png



SUPERCHUNKS + FRP:
Attachment:
MattE--REW--IR--180ms--Superchunks+FRp-L.png



IR is what you should be looking at mostly. And more correctly, ETC: Energy Time Curve. That shows what the energy is doing in the room as it bounces around. ETC tells you all you need to know about the room... Well, most of it.... Impulse Response is what acoustics is all about: That's what acoustics is! It's how your room RESPONDS to an IMPULSE of sound. That tells you everything that you need to know. Frequency response is interesting, and you'll get to that, but it is not the most important info that REW is giving you. I really wish that REW would default to the IR graph, not the FR graph, after it does a test! Maybe that would fore people to look in the right place... :)

And once again, the differences in your IR graphs stick out like a sore thumb.

So, yeah, I'd say that there's a little bit of difference now that you have started installing your treatment. Not much, though: just a humongous mountain of difference! (If you look in the right places....)


Quote:
because my ears definitely say things are better.
Your ears are telling you the truth! Just like the REW data is....

Quote:
And for the life of me, the levels still seem a bit low.
Did you calibrate REW correctly, according to my instructions? The levels look fine to me. All of those come from just your left speaker, and they are all around 80 dBC, which is fine.

Quote:
And after reading through the other thread, I'm even more determined.
You, too can end up with a studio like that! :) It can be done. He wasn't so sure about the outcome when we started, and listened to the wrong people telling him that it was impossible to tune a corner control room, that it was too small, terrible angles, etc... I asked him to trust the math, and the science, and the design... and today he's really glad that he did! :) As the saying goes: "the proof of the pudding is in the eating"... As long as your room is designed with the end goal in mind, then treated properly, then tuned properly, you can get results like that too. Or Studio Three... Or Steve's room... Or.... :)

Quote:
After going through a divorce, I'm still getting my finances in order.
Ouch! Sorry to hear about that. That hurts.

Quote:
I want to wow people.
You should be aiming higher than that! Check my signature.... :)

Quote:
If you have any recommendations I'm all ears.
Your first choice should be John Sayers himself. Ask him to quote you for doing that. If John is too busy to take it on, then PM me.

Quote:
Anyway I'm excited to see what can be done in here, and even more excited to build a proper studio from scratch.
:thu:


- Stuart -


You do not have the required permissions to view the files attached to this post.

_________________
I want this studio to amaze people. "That'll do" doesn't amaze people.


Report this post
Top
 Profile  
 
PostPosted: Sat Jan 26, 2019 8:14 am 
Offline

Joined: Tue Mar 24, 2015 10:42 am
Posts: 22
Location: Southern Oklahoma USA
Sorry about focusing on the frequency chart. It’s simply the one I understand best. I know it’s not even close to the most important part. And I guess I need to figure out how to better scale those other charts. I did look at those. But the waterfalls especially still looked like there was quite a bit of decay. I appreciate the insight for sure. And am happy to “see” more progress than I realized. :)

Also you mentioned noise. Yes there has been some. At least with the last two sets. I don’t remember about the situation with the middle set you picked. But I did do the last two measurements with people home. So their tv is playing. They have a soundbar. In the room I’m in, it’s not loud by any means, but definitely audible. I try to measure when I’m the only one home, but that’s just not been easy lately. Also the ac unit is outside the window in that room. Not directly but not too far away. I try and take measurements when it’s not running. But can’t promise it wasn’t in those. Again I was mostly trying to get a idea of where I’m at. So....

Since things are trending in the right way. I guess I’ll proceed like this. I’ll get at least enough insulation to finish the corners. I’ll fill those and take some measurements. It won’t be any issue at all to add some plastic sheeting to most of what I’ve done. The first reflections panels would be the most difficult to mod at this point. But definitely doable if that would be the best place to start.

So next time I respond I’ll have new measurements of the room with the corners filled. :) oh and probably stands built. I hope to build those very soon. :) again thanks again. It is appreciated.


Report this post
Top
 Profile  
 
PostPosted: Mon Jan 28, 2019 10:55 pm 
Offline
Site Admin
User avatar

Joined: Thu Aug 21, 2008 10:17 am
Posts: 11880
Location: Santiago, Chile
Quote:
So their tv is playing. They have a soundbar. In the room I’m in, it’s not loud by any means, but definitely audible.
I didn't realize that you had not isolated your room. OK. That might explain some of the noise, but not all of it.
Quote:
Also the ac unit is outside the window in that room.
That could be some of the lower-level, longer spikes, I guess.

Quote:
I’ll get at least enough insulation to finish the corners. I’ll fill those and take some measurements.
Definitely! But do consider putting plastic over part of that, or slats, in order to not overdo the high frequency end of the spectrum.

Quote:
It won’t be any issue at all to add some plastic sheeting to most of what I’ve done.
:thu: Do it selectively, carefully, so that you also don't go too far the OTHER way, with a room that is too bright.

Quote:
The first reflections panels would be the most difficult to mod at this point.
Don't put plastic on them. They NEED to absorb highs: that's what they do. It's mostly the bass traps that you need to do.

- Stuart -

_________________
I want this studio to amaze people. "That'll do" doesn't amaze people.


Report this post
Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 34 posts ]  Go to page Previous  1, 2, 3

All times are UTC + 10 hours


Who is online

Users browsing this forum: No registered users and 12 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group