Basement Control Room Design

[Gregwor]

Put your speakers perfectly vertical and put the acoustic axis of the speaker (typically this ends up being between the tweeter and woofer) at your ear height while sitting. Don't aim the speakers down like you are. Try that out and see how things look. You're on the right track here!

Greg

[buzzripper]

Not sure if it's an option to keep the speakers vertical. I measured sitting ear level for myself (48") and half the speaker gets cut off behind monitors:

VertSpkrPos_MixPos.jpg

VertSpkrPos_L.jpg

Moving the computer monitors is not an option.

I can manage to put the speakers in a position that's between the cloud and the top of the comp monitors:

AngledSpkrPos_MixPos.jpg

AngledSpkrPos_L.jpg

And I also had forgotten to include in the TV monitor and near fields. Even with angled speakers the view of the TV will be partially blocked by the cloud for anyone standing behind the mix position.

Whether I do vertical speakers or not, i'm not sure how i'll build soffits will with those ducts right there - what's at the top of the soffit? Do I build a little ceiling piece just under the ducts for the top of the soffit to connect to? Then i've got even less vertical space to work with.

The other side of the room keeps looking better and better....

[Paulus87]

Looks like you’re measuring to the middle of the woofers instead of the tweeters....

Turn your monitors upside down and have the tweeters at ear height. That should solve the problem and you’ll be able to keep your monitors at the right height without angling them vertically.

Paul

[Gregwor]

And I also had forgotten to include in the TV monitor and near fields. Even with angled speakers the view of the TV will be partially blocked by the cloud for anyone standing behind the mix position.

My plan for my personal build is to run a mirror image screen back to the client/producer position. I will somehow fix insulation on the back side of the screen. Unless you have a 50"+ screen in front of you for them to see, they're going to have difficulties seeing the details of what's going on clearly anyway.

Looks like you’re measuring to the middle of the woofers instead of the tweeters....

Typically the acoustic axis of the speaker is right in BETWEEN the tweeter and the woofer.

Turn your monitors upside down and have the tweeters at ear height. That should solve the problem and you’ll be able to keep your monitors at the right height without angling them vertically.

Greg

[Paulus87]

Typically the acoustic axis of the speaker is right in BETWEEN the tweeter and the woofer.

Yeah, in a precision designed monitor the acoustic centre of the speaker is usually in between the drivers, provided that the drivers have been properly physically aligned and delay compensated, but on two way near field monitoring like the ones in his design they usually are not physically time aligned. The problem is each driver has it's own acoustic centre, not just the speaker as a whole, and the source of where the signal begins from each driver does not necessarily coincide with any physical part of the speaker. In other words, a good compromise on such speakers is to use the tweeter as your reference point for measuring ear height as it produces the most directional energy and has the biggest influence over the stereo image.

Paul

[buzzripper]

Hi, finally getting back to this after moving and having a zillion things to do. So here's my latest design:

SideNoFraming.png

SideWFraming.png

TopNoGear.png

TopWGear.png

So my questions are:

1. If I want to really minimize my cost and effort, is it reasonable to simply do this?
- Put 5/8" drywall around the outside
- Put 703 board between all the joists
- Pack fiberglas and hang absorbers in the speaker soffits
- Cover a the inside of the walls with cloth
- Put a diffusor on the back wall

2. Anything special I need to do for having surround speakers?

3. What should I do over the ducts? I can't afford to line them with that expensive rubber stuff - should at least put drywall around them to stop them from ringing?

I know this is all pretty overly simplistic, but I guess I'm just looking to do the minimum to have reasonably decent acoustics. Just looking for suggestions of really obvious things to avoid, to keep me out of trouble.

Thanks!!

[Gregwor]

1. If I want to really minimize my cost and effort, is it reasonable to simply do this?
- Put 5/8" drywall around the outside
- Put 703 board between all the joists
- Pack fiberglas and hang absorbers in the speaker soffits
- Cover a the inside of the walls with cloth
- Put a diffusor on the back wall

Yes.

2. Anything special I need to do for having surround speakers?

Yes, but I can't help you with that as I've never tackled such a design. You might want to hire John Sayers to assist with that design aspect.

3. What should I do over the ducts? I can't afford to line them with that expensive rubber stuff - should at least put drywall around them to stop them from ringing?

I would probably wrap them with insulation and frame around them using small lumber (like 1x2) and then cover that with OSB. After that, I would mount some impaling clips and push some 703 onto the clips then wrap that with fabric. It would dampen the duct work, maintain your isolation and prevent reflections from screwing up your acoustic response.

impaling-clip-4.jpg

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It looks like your doors might be in a crappy spot acoustically speaking. I believe you're better off having shorter doors and putting them under the duct work. Also, I can't say for sure due to you maybe wanting surround speakers, but if you are going for an RFZ design, your doors might be in the way of your soffit wings. Also, be sure to add noggins on either side of your door framing. Lastly, be sure to check out how to properly frame rough openings for doors as it looks like you're doing that wrong. A few quick google searches will get you on the right track quickly

Greg

[buzzripper]

So I'm starting to look at cost, and it's pretty depressing! Trying to keep on a small-ish budget, but I don't know enough to know where it's ok to cut corners and where it's not. Again, this is not a pro installation, just trying to get mixes I can trust, to reasonable degree. To that end I've got a couple questions:

- How much worse is it if I use Safe 'n Sound instead of 703 in my walls and celing joist cavities? Pretty significant price difference, but not sure how much of a dropoff in effectiveness. The 3" i'm looking at has a density of 38 kg/m³

- What kind of cloth should I use? Maybe I'm just missing it but I can't find a specific recommendation anywhere.

- How do superchunks compare with the homosote/703 hanging baffles that I see everywhere? It's just a 14' x 15' x 8' room so I'm thinking this is a pretty an important issue, correct me if I'm wrong

Thanks!

Andy

[Gregwor]

So I'm starting to look at cost, and it's pretty depressing!

I feel that!

- How much worse is it if I use Safe 'n Sound instead of 703 in my walls and celing joist cavities? Pretty significant price difference, but not sure how much of a dropoff in effectiveness. The 3" i'm looking at has a density of 38 kg/m³

If you're looking to cut costs, this is a smart move. Safe'n'Sound is actually pretty great!

- What kind of cloth should I use? Maybe I'm just missing it but I can't find a specific recommendation anywhere.

You're going to get better high frequency absorption with a more breathable cloth. I believe it's really that simple.

- How do superchunks compare with the homosote/703 hanging baffles that I see everywhere? It's just a 14' x 15' x 8' room so I'm thinking this is a pretty an important issue, correct me if I'm wrong

I have never seen a room tested to see the difference in performance. As I'm sure you've learned, hangers are really expensive to build as Homasote is not cheap. If you also find that it is cheaper to make a nice thick rear wall of insulation rather than hangers, then I suggest doing that.

Greg

[buzzripper]

Thanks Greg. Ok so here's my latest plan, hoping I'm getting close but not sure....

For reference, here's the open space:

CtrlRoomLocation.png

Model-Framing-Side-Callouts.png

Model-Top-Gear-Callouts.jpg

Duct treatment:

DuctsTreament-Callouts.jpg

SoffitBaffles.jpg

My one big question is the diffuser(s). I see plenty of discussions, and apps/sites for calculating how to build them, but they all seem to require you to put in frequency ranges etc. and kinda know what you want already. This is stuff that I really have no clue, I need something that I can input my room dimensions and it will tell me the details of the diffuser to build and I'll build it. Maybe it's not that simple but not sure where to go.

I may scale back on the front soffits and just fill w/safe 'n sound, and not do hangers, still deciding.

Think I need to adjust anything else? Probably a lot! I'm getting ready to pull the trigger on this thing. Already asked to take a week's vacation to get things rolling, so hope I'm at least close. But interested in any/all suggestions.

Once again - thanks!

Andy

[Gregwor]

Sorry for the late reply. Did you find time to build much?

Regarding your rear wall treatment, how far from the face of your diffuser would your ears be?

Greg

[buzzripper]

Hi Greg,

No problem, I'm grateful for any reply you can give me. I'm just completed the front and back walls today (took a vacation week to work on this).

My ears will be about 8 1/2' from the front of the diffuser (about 14.5' long room). Let me know if you need more exact measurements.

Here's what I'm planning:

Overhead.png

I'm adding that little rear wall to make room for a 5.5" deep diffuser and more insulation. Planning on filling everything around the diffuser and in the corners with Safe n Sound.

What do you think? I'll probably be building this in a couple days or so...

Thanks again!

Andy

[buzzripper]

I'm way overdue with posting these pics. Many thanks for those who helped me out, especially Greg! Couldn't have done it without you. I've probably screwed up a ton of things, but I'm just glad it's finally done.

Here's a slide show with all the photos

Here's a couple highlights...

This is the basement area I started with:

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20201205_140452.jpg

The REW graph looks relatively flat, I think, at least for an amateur like me, but I don't have much to compare it to. Not sure why high end is so wicked choppy, hope I didn't screw things up with my diffusor. And the phase looks pretty wacked, but not really sure what it should look like. Guessing it shouldn't look like that tho. And definitely have some buildup at 100hz, but not sure how to fix it.

REW Graph.png

If anyone has suggestions / feedback I'd appreciate it.

Thanks again, this is really a nice site.

buzz