Another (small) mixing-room build... (with before/after results)

  • Thread starter Thread starter GhostsonAcid
  • Start date Start date
GhostsonAcid

GhostsonAcid

New member
Hello,

So I recently finished renovating my relatively small music-editing room. Like many people, I didn't have much of a budget... -but I did have time, some building skills, and basic creativity. Believe it or not, but in the end I spent less than 200€/$ on all of my 13 panels and speaker stands. So yes, with some basic skills and some time it is possible to easily make your own, effective sound panels/traps for a tiny, tiny fraction of the cost of buying them new. Hopefully this post will lend some ideas and inspiration to others out there who wish to do a similar thing!

(I would also like to note that, although probably not that necessary in my case, I designed and 3D-printed some spring-based “isolation feet” for my Yamaha HS7 speakers, -designs I will link to here when I get around to uploading them to my Thingiverse page...)

IMG_3576.webp


? Step 1: Determine the best possible location(s) for the listening position, speakers, and various potential sound panels.

The room in question is pretty small, with length/width/height ≈ 4.6 x 2.4 x 2.4m (or ≈ 15' x 7'10” x 7'10”) (-although an empty 20-25cm (8-10”) cavity in the ceiling effectively brings the height to 2.6+m (8'6”+), -something I was reminded of later via a prominent room-mode resonance peak at ~137Hz for heights at around 260, not 240cm (-more info. below)).

There is a noticeably off-center fireplace, two windows, a brick-wall portion in just one of the corners, and a door adjacent to one of the preferred listening-positions... -all not ideal, but whatcha gonna do? … -Actually, go to Homerecording.com, of course! So yeah, I posted here about it just to see what others might say...

Blue Room Basic Layout Measurements.webp

Long story short, I chose the spot by the door. -It's a place with a window (-for my health; -for the light/trees/etc.), and a place where my head wouldn't have to be up-against the fireplace (-a big sound-reflector). Well, with that decided (and no initial speaker placement testing, like an idiot :facepalm:), I used paper (and then FreeCAD) to help confirm viability of the location, and potential sound-panel placement/distribution, etc.:

FreeCAD - Music Room 5.webp

FreeCAD - Music Room 1.webpFreeCAD - Music Room 2.webpFreeCAD - Music Room 3.webpFreeCAD - Music Room 4.webp

Now, due to a 10-picture limit per post, I will continue in the comments below...
 
Last edited:
?️ Step 2: Generic fixing, spackling, painting, etc..

Here are some pictures of the room right at the beginning...

IMG_2698.webp


IMG_2702.webp
IMG_2703.webp
IMG_2706.webp
IMG_2713.webp
 
Last edited:
? Step 3: Design sound-panels, buy the materials, and get building!

Most of the following images speak for themselves, but here are some more details anyway:

I decided to build 13 panels (-more like 11, but two of them had to be 'split' to accommodate for the awkward brick-wall that juts-out in one of the back corners). They would be made of generic RockWool insulation, 2.5x5cm (1x2”) wood, 3.2mm sheet material, some other wood scraps, and agroplastic (-for anyone wanting a good tool to help you determine how much agroplastic/fabric/etc. you would need for a particular project, I recommend this tool: https://www.cutlistoptimizer.com/ ). The hypotenuse of the corner traps would be ~50cm (~19.5”), and the thicknesses of the rectangular panels would be either 15cm (~6”) or 10cm (~4”) thick. Also, all hanging panels would have at least a 5cm (~2”) gap behind them (for better low-end absorption).

Like many others, I got decent ideas (such as applying duct-tape to the corners) from this popular video:



IMG_2730.webp
IMG_2737.webp
IMG_2741.webp
IMG_2746.webp
IMG_2812.webp
IMG_2821.webp
IMG_2827.webp
IMG_2831.webp
IMG_2864.webp
IMG_2867.webp
 
Last edited:
IMG_2933.webp
IMG_2946.webp
IMG_2948.webp
IMG_2967.webp
IMG_2968.webp
IMG_2969.webp
IMG_2971.webp
IMG_2972.webp
IMG_2973.webp
IMG_2975.webp


-Then add a 6€/$ LED strip-light on top of it and you're all set! :thumbs up:
 
Last edited:
?:unsure: Step 4: Installation, Measurements, and Other Changes...

After installing all of the panels, a quite distinct resonance near 137-140Hz was still intolerably bad... I knew the ceiling was hollow (-not necessarily good for a mixing room....(?)), but I wanted to know just how big the space was, and if it was significantly contributing to this spike. It turns out it varies from 20-25cm (8-10”), and when I account for this extra height, a new resonance appears right at 137Hz, according to the Amroc room mode calculator, -another awesome tool:

Possible Major Room Mode Resonance, 137Hz.webp

Possible Major Room Mode Resonance, 143Hz.webp


In an attempt to dampen this vertically-oriented mode, I went into the attic, opened-up the floor, and stuffed it with hay. (Yes, my house is so old it has a dirt-floor in the attic. :D) According to before and after measurements, this did in fact improve the intensity of the ~137Hz resonance by about 1.5-2db! -Pretty tiny, yes, but at least not nothing, haha. It goes to show the power of room-modes, and that if you really want to "deal" with them, you need to design your room from the ground-up.

Adding Ceiling Hay 1.webp

Adding Ceiling Hay 2.webp

Ceiling Hay Improvement Example.webp
 
Last edited:
:guitar: Step 5: Room EQ “Correction”, and Final Results...

As a final step, I created and tested various room EQ “correction” settings based off measurement data from a very cheap (40€/$) Behringer ECM8000 measurement microphone. -Some auto-generated by REW (-another killer tool that does so much!), but most made manually by myself through careful/thoughtful tweaking. When working with EQ changes, I found it can be helpful to use REW's signal generator (or any other), and just go to and from various frequencies to hear which areas are obviously louder or quieter than others, and then make EQ adjustments as necessary, checking around again, re-adjusting, and so on... -honing-in on what truly sounds more-or-less balanced. And check with music you're familiar with too, obviously. (And for making these system-wide EQ changes, I used a program called SoundSource (on my Mac), and FabFilter's Pro-Q 2.)

Here are various results of the 'before and afters':

Music Room - SPLs 1 (All Measurements).webp
Music Room - SPLs 2 (Before Panels).webpMusic Room - SPLs 3 (With Panels).webpMusic Room - SPLs 4 (With Panels+EQ).webp

I heard 1/3 is a common, 'final' smoothing applied, so here's what that looks like for me, although I still feel it's kind of 'cheating', haha. Also, if you're wondering about that low-end boost from 40-70Hz, I'm pretty tempted to keep it for better low-low-end decipher-ability. I agree in general with the idea that a modest slope going up in the lows is acceptable/preferable:
Music Room - SPLs 5 (With Panels+EQ).webp

Music Room - SPLs 6 (With Panels+EQ).webp

My Current Room EQ "Correction" Settings.webp


Note that if you choose to do some boosts in an EQ like I did (instead of just cuts), to avoid speaker clipping/distortion you will need to lower all of the incoming (to the EQ) gain by a little more than what your EQ is now capable of adding to a signal. For this I used Airwindows PurestGain plugin to apply around -7db (-check out more of his plugins, -they're awesome, and totally gratis). Even with this loss of volume, the HS7s have more than enough drive/output to satisfy my needs.

Some waterfall charts, for those interested:

Waterfall Graph 1 - Without Panels.webpWaterfall Graph 2 - With Panels.webpWaterfall Graph 3 - With Panels + EQ.webp
 
Last edited:
And here is what the final room looks like...
-Not the most epic in the world, but alright for an ultra-shoestring budget in a house almost a century old! ??
Also, it's hard to capture it all in one image (-and it's pretty messy too, sorry... (-great for the diffusion, though!)):

IMG_3296.webp
IMG_3556.webp
IMG_3565.webp
IMG_3569.webp
IMG_3573.webp
IMG_3576.webp
IMG_3586.webp
IMG_3587.webp
IMG_3589.webp
IMG_3595.webp


So anyway, thanks for having a look!
I'll be happy(?) to read anyone's comments/critiques, or answer any questions, etc.!

~Peace! ✌️
~And have fun making music!


-Joe
 
Last edited:
Back
Top