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PostPosted: Sun Nov 22, 2020 12:40 pm 
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Joined: Sun Nov 22, 2020 12:33 pm
Posts: 3
I] SOME BACKGROUND

Hi guys !

First, excuse my english mistakes, it's not my first language ;)
I recently moved and decided to treat myself with a decent home studio installation.

I already owned all the musical gear, I guess the only (maybe ?) relevant piece are the monitors : those are KRK Rokits RP7 (G4 versions, massively improved regarding flatness).
I'm the "reads everything about it for 3 weeks before making a move" kind of guy when it comes to this kind of projects, so I learnt a lot about sound physics and the problems that could occur in a room, and how to treat them. That being said, I'm FAR from being an expert, just wanted to let you know I'm kinda understanding shits about the matter :)

I already bought/built and installed everything, and made some before/after measurements. So I'm not here to ask the recuring "I want a treated home studio, what should I do ?" question, but to ask for help regarding my measurements interpretation, and maybe get insights about some problems that still exists with the room (can/should I try to treat them ? what are my alternatives ?).
I'll describe the room, the acoustic treatment installed, and show the measurements, then I'll ask my questions :)


II] THE ROOM

As you'll see on the below map and 3D view, the room is pretty long (roughly 310 x 630 x 250 cm).
I know this is not ideal for a studio, but I don't have the choice, this is the only room available for this.
There's 6 panels on the walls, and 8 basstraps covering 2 corners of the room.

Panels : the panels are Gikacoustic 242 panels, you can look it up on their website for the specs : https://www.gikacoustics.com/product/gik-acoustics-242-acoustic-panel/.
I bought those since it seems that classic 2-5cm foam pads won't do much regarding acoustic treatment, or only in high frequencies.
242 panels, on the other hand, seem to be effective on mediums too.

Basstraps : I didn't have much money left for basstraps so I decided to build DIY basstraps.
I made 60x60x85cm triangles (60cm high each), with a wooden structure, and entirely filled with rockwool (25 kg/m3, AFr5).
I figured light materials with a little air flow resistivity are the right choice for superchunks like this.

Attachment:
1_3d_room.jpg


Attachment:
2_room_map.jpg



III] THE MEASUREMENTS

I made all my measurements using REW. My microphone is a Superlux ECM-999, plugged into my Scarlett 4i4 audio interface.
I don't have a calibration file for the microphone, but I guess it is precise enough for the quality of treatment I'm aiming for, I'm not a professional after all.

I'll put titles and legends around every graphs so you know what you're looking at :) If you're missing graphs I didn't put there, feel free to ask, I don't know all useful informations regarding measurements.
(I didn't put measurements with both monitors at the same time since I think it can be tricky to read, but I have those too if required).

LEGEND FOR ALL GRAPHS :
RED : empty room.
GREEN : treated room.


1) SPL

Attachment:
3_spl_left_1-24.jpg

LEFT MONITOR : 1/24 smoothing.

Attachment:
4_spl_right_1-24.jpg

RIGHT MONITOR : 1/24 smoothing.

Attachment:
5_spl_left_1-3.jpg

LEFT MONITOR : 1/3 smoothing.

Attachment:
6_spl_right_1-3.jpg

RIGHT MONITOR : 1/3 smoothing.

2) RT60 (Topt)

Attachment:
7_rt60_left.jpg

RT60 : LEFT MONITOR

Attachment:
8_rt60_right.jpg

RT60 : RIGHT MONITOR

3) Waterfalls

Attachment:
9_waterfall_left_before.jpg

LEFT MONITOR - EMPTY ROOM

Attachment:
10_waterfall_left_after.jpg

LEFT MONITOR - TREATED

(I won't put right monitor waterfalls since they're sensibly the same).

If you want to download the measures and open it in REW yourself, here are the files : http://clementgonin.fr/room-treatment/clem_treatment_measures.zip


IV] QUESTIONS

If you're still reading this, lets go with the few questions I'm asking myself about all this :

1) First a general question : does the treated room response seems good enough to make some proper mixing/mastering work ?
Or are the problems still too present to really call this a "studio" ? :)
(Keep in mind that I'm not a professional, but I'd like to do things the better I can with my means).
I feel like the reverberations have been mostly tamed succesfully, but that the SPL graphs aren't that good. Do you second that ?

2) About SPL : you can notice that on the left monitor, the problem around 120 Hz as been amplified (a lot) after the room treatment...
I guess this is because some sound waves phases was nearly 180° shifted and they was canceling each other, but aren't anymore with the addition of bass traps ? Or is there another explanation ?

3) On the RT60 and Waterfall graphs, you can see that I still have pretty big reverberation problems below 100 Hz... I guess this is because my DIY basstraps conception isn't that good in the end, and that they aren't working on those frequencies ? Or is it just the lack of basstraps in other corners that is a problem ? (I sadly can't fill the 2 other corners of the room).

4) I've been hesitating to buy some treatment for the floor and ceiling. Do you think it would be a useful addition to my current setup ?
I guess it wouldn't be effective on low frequencies anyway... so since my high frequencies are already more a little more tamed than mediums, I think I shouldn't do it, since I'd tame the upper spectrum even more and the room would feel "dead" ?

5) I know there is some software solutions to apply an EQ on all audio going out of the computer.
Do you think it would be a good idea to use one to deal with those 70 and 120 Hz bass problems ?
As I understand this, it can be useful for bass since the problem will be the same in a 40cm circle around my listening position, but don't really make sense for mediums and highs, since the variations in SPL would be different every 5cm in the listening position, and the correction could do more harm than good...
(The Rokit G4 have an EQ in the back, it's set on flat for now but I'll adjust it if it seems to improve the flatness of my room response).

6) If you have anything else to say, feel free to do so ! I'm sure I'm not thinking about everything, and I know a lot of people here are far more expert than me about those matters, enlighten me !


Well, that will be all guys, that's a pretty dense post already...
Thank a lot for your time and expertise !
Any advice or piece of information will be greatly valued :)

Clem


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PostPosted: Mon Nov 23, 2020 8:21 am 
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Joined: Sun Nov 22, 2020 12:33 pm
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Actually, maybe this post should be in the "Studio design" forum and not in Acoutics ?
If a moderator see this and thinks it would be better in Studio design, feel free to move it ;)


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PostPosted: Mon Nov 23, 2020 8:58 am 
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Joined: Tue Mar 25, 2008 3:31 am
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Location: Cork Ireland
Your questions are mostly Acoustic IMO.
Obviously there is inadequate LF treatment. The problem of very long decay would become much worse if your speakers delivered decent LF
They are tiny speakers, they would probably benefit greatly from almost touching the Front Wall.
Clouds and Side Reflection Absorbers are a must, as is a decent back wall or corners attempt. Note the wall ceiling and wall floor junctions are both corners.

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PostPosted: Mon Nov 23, 2020 8:48 pm 
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Joined: Sun Nov 22, 2020 12:33 pm
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Quote:
They are tiny speakers, they would probably benefit greatly from almost touching the Front Wall.

About the speakers placement : the documentation advise to put it at more than 1m from any wall.
Before putting the treatment, I made a bunch of measurements to determine the best speakers/listening position.
I took measures every 10cm between 25% and 45% of the room length as listening position (while moving the monitors too to maintain an equilateral triangle between the 3), and my current position is the best I could find with an empty room.
Do you think it could have changed with the addition of basstraps ? The best position could have moved ?
My guess was that since those problems are linked to the room size, the best possible position with an empty room would be the best with treatment too, but maybe I'm wrong.

Quote:
Clouds and Side Reflection Absorbers are a must, as is a decent back wall or corners attempt. Note the wall ceiling and wall floor junctions are both corners.

So you'd advise to put some treatment on the ceiling, and more treatment on the back wall ? Since it won't affect LF (I think ?), I guess this isn't the first thing I should resolve ?
Those LF decays and SPL seem to be a bigger problem... adding more basstraps to the wall ceiling and wall floor junctions may do the trick ? "Professional" ones, or DIY should do ?
(The problem I have with this back wall is that there is 2 doors on it, so I can't really put permanent panels easily, maybe I'll try to make some at the right sizes with the rockwool I have left.)


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PostPosted: Tue Nov 24, 2020 8:21 am 
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Joined: Tue Mar 25, 2008 3:31 am
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Location: Cork Ireland
Try the speakers almost touching the Front Wall. Here is an improvement I experienced when moving speakers from a couple of feet out to pretty much touching the wall.
Attachment:
White Room copy.png


The Why.....http://arqen.com/acoustics-101/speaker- ... erference/

Bass Modes gather like street urchins in corners. Including Wall Ceiling and Wall Floor. Treat Big to try to get at your long LF decay.


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http://www.irishacoustics.com
http://www.soundsound.ie


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