Salem Oregon conference center studio

The speaker enclosures are pretty-well lined with Roxul. The middle bass trap sections aren’t so deep and I didn’t find room to line the back with Roxul because the hangers would loose so much depth. Any thoughts on that? The total depth of the middle frame to the wall is 11 3/16”.

Stuart, do you care to comment on my previous question? Is it better to loose depth on the middle-lower section in order to put about 1.5" of OC 703 to line the back wall or just leave it as is (unlined) and have a little more depth on the hangers? -Ron

Darn! I keep replying late to your posts! :oops: Sorry about that.... I'm tracking a ton of threads at once, and sometimes one or two slip through... Anyway, I agree with Tom: you do need a couple of inches (at least!) of insulation on your walls, behind the hangers. Also on the floor and ceiling, above and below the hangers. Part of the way hangers work is to redirect the sound waves away fro their original path, into the walls behind where they can be partly absorbed, then partly reflected back, but at a different angle, where they will hit the hangers once again.. So you need thick absorption on the walls, yes. - Stuart -

Hey, thanks Stuart. Thought you were off building a studio in some remote place! :lol: As you can see, I haven't been on the forum for a bit - for a good reason: I've been building the left and right speaker soffits in between life obligations. I will line the back wall with insulation. * Would Roxul 3" safe-n-sound work too in places, or must it all be OC 703? I need to download REW soon and start the learning curve. I expect it will be necessary to buy a suitable mic. I need to research that. Here's a photo of the soffit progress. I haven't framed in the spaces between yet.

Ron, Opposed to buying a mic you can borrow mine if you want. It has one use and one use only :( Let me know T

:o 8) Wow! Thanks, Tom! How very nice of you! Even tonight I was going to email you about visiting your studio. I'll fire you an email now... -Ron

I haven't been on the forum for a bit - for a good reason: I've been building the left and right speaker soffits

Nice! They are looking very "beefy", which is good! You want them tough and rigid.

* Would Roxul 3" safe-n-sound work too in places, or must it all be OC 703?

Yep, that should be fine. The specs are reasonably similar.

I need to download REW soon and start the learning curve. I expect it will be necessary to buy a suitable mic. I need to research that.

Not sure if you've seen this thread, but I cover mic selection, and also sound level meter selection: How to calibrate and use REW to test and tune your room acoustics

Here's a photo of the soffit progress. I haven't framed in the spaces between yet.

What's your plans for mounting the speaker itself? - Stuart -

Not sure if you've seen this thread, but I cover mic selection, and also sound level meter selection: How to calibrate and use REW to test and tune your room acoustics

Yes, I have the link and will soon be digging in. Thanks! So glad to have this to start out with, since I am soon to enter into the "scary" acoustics phase, being green on this.

What's your plans for mounting the speaker itself?

It's funny you should ask! I've been building the speaker mounts and just finished the assemblies yesterday. You may recall we talked about that at length quite a while back and I've had the design ready to go since a year ago. This should refresh your memory: Here is the drawing of the assembly, using plywood and sorbothane pads. There are T-nuts embedded on the right and left assemblies in order to "dial" in the compression with the bolt: It is attached to the soffit shelf like this (speaker missing for viewing): With speaker: ...and here's the real deal as of last night (on kitchen counter on blocks): I used nylock nuts with washers and found that I needed to put them on both sides of the top and bottom pieces to keep things straight and inline. The amount of compression on the top verses the bottom sorbothane hemispheres (different quantities and sizes) worked out nicely with the specified range of 20 to 30% compression. I was very pleased. Dialing it in was a bit tedious, but not hard. After a couple of calls to the engineer at Sorbothane a year ago, I had selected a combination of two sizes that put me in the right ballpark. For below the speaker, I had to take into account the weight of the speaker and the expected pressure from the top absorber. It turned out to require five smaller pads to work out. The sides are the same as the top. It was neat to see that the compression ratios of top and bottom actually worked out as expected.

Looks like it should work! :thu: That's not exactly the way I do it, but not far off... Have you tested it yet? Play loud music, with plenty of low bass content, and check the wood panels for vibration, with your fingertips. - Stuart -

Looks like it should work! :thu: That's not exactly the way I do it, but not far off...

I borrowed from barefoot's design and used threaded rods and bolts rather than a strap to hold things down. I liked his idea because it lends itself pretty good to make it easier to replace the speakers some day down the road without tearing the whole front end out of the control room.

Play loud music, with plenty of low bass content, and check the wood panels for vibration, with your fingertips.

Good idea. I will do that.

Hi Stuart, I have a partner who is going to work with me and get through the learning curve on REW. Right out of the chute, we're not understanding how to even hook up the loopback to calibrate. I feel really stupid for asking, :oops: but after a couple of hours of reading through both your instructions and REW help files, we are really confused: For a typical calibration in my 2-channel system (no sub), would I hook up TWO cables from speaker output L & R to input 1 & 2? You're probably going to roll your eyes over this! :roll:

For the soundcard calibration, you hook up a simple cable that goes from either the left speaker output OR the right speaker output of your sound card, directly back in to the line input channel of your sound card (where you will connect the mic later). That's all! This is not applicable if you use a USB mic: only if you use a proper audio interlace device (what the REW manual calls a "soundcard"). Also, do check that you have the latest version of REW installed: the current version is 5.20 Beta 23. - Stuart -

Thanks Stuart! I have my elderly Dad's funeral to arrange this week and then we will go to work on it. I really appreciate your quick response. :)

Care to share the calculations you did for the Sorbothane pads? Greg

Greg, My profuse apologies. My world has been hectic between work, family matters, keeping the home running and ..... then there's the studio! I have been out of the country for a while too. I didn't get onto the forum until now. The good news is, we figured out how to ring the control room for the first time and also built a pedestal in the back of the control room that will raise up the rear couch a ways. More on that later.

Care to share the calculations you did for the Sorbothane pads?

To answer your question, I retraced my steps on that, since I seem to have lost my notes. My speakers weigh 29 lb, 13oz (15.5kg), so let's say 30 lbs each. Here is the 2018 product guide from Sorbothane: https://www.sorbothane.com/Data/Sites/3 ... ne-SPG.pdf I was advised by Sorbothane to use hemispheres. He apparently gets a fair amount of speaker isolation calls. If I recall, I think he recommended a "duro" value of 30. I realized that for the bottom pads, I will have to account for the weight of the speaker as well as the downward weight of the top pad. For the top and sides, I chose part number 0510150-30-10, which has a diameter of 2.5", height of 1.25" and a load range of 25 to 35 lbs. Adding the 30-lb speaker weight and the mid-range top pad pressure (also 30 lbs) I realized I had to find an array of bottom pads that would be within range with 60 lbs. That worked out by using five of part number 0510141-30-10. Each pad has a load range of 11 to 16 lbs. Dividing 60 lbs by four pads yields 15 lbs (near the top of the range), so I used five pads, which puts it at 12 lbs each (on the lower side of the range). In the real application, I found that the compression worked out pretty nicely. I was prepared to remove one pad if the compression on the top and bottom weren't both near 20 to 30%, but it didn't turn out to be a big deal. The side pads are the same as the top. It was a no-brainer - just dial in the amount of compression. All of the hemisphere pads cost me $67.90 with a couple of each size extra. They only came in 4-packs. Hope this is useful info. I ain't no expert, you know! :wink:

That all makes sense to me! Thanks so much for sharing. I really look forward to your couch riser posts! Greg

Here's the details of the couch pedestal: We used 2x10 pressure treated lumber. First, we cut and assembled the outer circumference and anchored it to the concrete floor. Next we sealed all around the inside, between the joints and along the floor with silicone seal. Next we spread a visquine plastic sheet. Lastly, the middle cross pieces were put in. We cut two pieces of 3/4" plywood to fit, but did not attach yet. At this point, I took opportunity to have the floor installed. Now all the flooring is installed in the entire studio. I enlisted a few energetic youth who are waiting anxiously for a recording studio (all are excellent musicians - one with a degree in music). We took a bunch of junk bricks and cinder blocks to fill in as much as possible. Then ... ... filled it with medium grade (dry) sand and ... ,,, screwed the lid down. The front will be lined with MDF and the top will be covered with a short-pyle commercial carpet remnant, I expect. It will be covered by the couch except a little on the sides. Everything behind the couch will be bass trap, of course. Here's another angle through the sound room window. Now I need to draw the details of the back bass trap and hangers. Then I can order the homosote and the 2" fiberglass OC703 for both the front and back of the control room.

Oh, I almost forgot. I added a little detail to the flooring you might think is novel: Take a close look at this picture of the flooring. It is directly in front of the pedestal. You can see two round inlays - one at the top of the pic and another below. They mark the focus point of the speaker and the sweet spot. I got some free samples flooring pieces of the same style, but different color, from Home Depot. I carefully embedded these into the floor for a permanent mark of these important points. I had to practice a few times with scrap pieces before we installed the floor.

Awesome stuff!!!! Keep us posted please! Greg

I got started drawing the back bass trap for the control room. The most difficult part right now is getting around the slope of the ceiling. It drops about 10 inches in 2 1/2 feet. Since I have a corner control room configuration, that causes a weird angle on my ceiling, which is unsymmetrical. I knew it would come back and haunt me and now I'm facing it. This is what I came up with: I added a black line where the ceiling takes the downturn. Here's a more-vertical view to get a better picture: So, you see that I have resorted to turning the hangers 45 degrees to accommodate the ceiling angle. I saw someone else did the same thing on the forum (for difference reasons), but can't find it now. Is this crazy? Will it impede the bass trap by such a steep angle with respect to the speakers? If so, I'm going to have to get very creative, putting weird-shaped tops to the hangers and then figure a way to hang them straight from a slanting rod overhead. What think ye? -Ron

why not try something different and more effective. This is the math. Vertical slots are more effective at absorbing low end and they diffuse the high end here's them in action. https://www.johnlsayers.com/Pages/Image ... trol_1.jpg and in this corner control room. https://www.johnlsayers.com/Pages/Image ... r_slot.JPG cheers john

Hey! Thanks John! I really like this! I will have to go through a bit of a learning curve and will have some questions. I need to understand more details than I can determine with a 2-dimensional drawing. Starting with the first stupid questions, but the rectangular in your drawing are pieces wood, right? Then, does the depth of the pieces matter? I'm thinking the depth of the cavity is the only concern, right? Would I put a layer of rockwool or OC703 behind the slats and/or on the back wall? I don't know how to calculate the depth of the cavity since it is at a 45 degree angle. Would I just choose the greatest depth in the calculator? Thanks so much for your nudge. I REALLY like the idea! -Ron

Ron, the squares are vertical 6" x 2"s with a 1/4" space between them. They are at 45 degrees from the side walls. The depth is the same as you've already built and because they are mounted across the corner the depth varies. Check the photos I posted. cheers john

Yes, thanks John! I appreciate your attention. Please bear with me. I looked again at the photos - very nice, I would add. So how can I use the calculator with different "depth from wall" all across? Do I use the deepest depth (i.e. the corner of the wall) in the calculator? I am confused with the differences in the drawing included in the calculator and the 45-degree drawing. Should I assume I would use 2" slat width (or 4" on pieces that are butting together) and 6" for slat depth in the calculator? What I'm getting at is the difference in the two examples, where one is on a flat wall with flat slats and your corner example has really deep varying slats, some with no gap and some with gaps and each one is a different depth from the wall. Perhaps I should take all of the individual depths and average them? No arguing is intended here, but I'm just trying to understand how to apply the calculator with all these variables. I am really intrigued by your design and want to go further with it! By the way, where can I link to the calculator? Best Regards, Ron

Here is a post John made describing his amazing device in more detail: viewtopic.php?f=2&t=12365&p=135094&hilit=It%27s+a+vertical+slot+resonator#p135094

By the way, where can I link to the calculator?

http://johnlsayers.com/Recmanual/Images ... perial.xls I'm so glad John shares his designs in such great detail! Greg

Thanks Greg! There's a wealth to study in that thread you shared. Just what I need. 8) I am still unclear about how to apply the calculator in the corner application, :? but I will start with a first-draft drawing with what I understand so far after reading the thread.

I'm so glad John shares his designs in such great detail!

...and so am I!! :D Thanks John! I don't know what I'd do without this forum! :wink: Gratefully, Ron