Rehearsal Space in Katy Texas

[Soundman2020]

Did you put the second pane of glass in already? I hope not, because you seem to be missing a rather important item. Or maybe you did put it in, but forget to mention it.

I'm talking about the desiccant. You need something in the cavity between the two panes of glass to absorb the moisture that is trapped in there. If you don't do that, then there's a good chance that sooner or later the moisture will condense on one or other of the panes, marking it, and without any way to clean it off. There are several suitable desiccants, but the most common is plain old silica gel. There are equations for calculating how much you need based on the volume of air trapped between the two glass panes.

I'm really hoping you did that already, or that the second pane of glass is not yet in place...


- Stuart -

[spiraloutdrummer]

No, I did not. I thought I read in the forum or Rod's book that you CAN put it in, but should not be necessary if everything is built correctly. I don't have a problem yet, but when I get a/c and the weather changes, I might have a problem. If that happens, I will have to remove the glass and deal with it. I'll confess when the time comes and post the reconstruction.

Erik

[Soundman2020]

I thought I read in the forum or Rod's book that you CAN put it in, but should not be necessary if everything is built correctly.

Right, but I prefer to err on the side of precaution. Maybe too much: I'm sort of a perfectionist...

But I did note that you live in Texas close to Houston (humidty...), and there's a swimming pool right outside that window (lots of humidity coming off that) so I was concerned that there is likely some extra moisture trapped in there that might come back to haunt you when the glass on one side gets cool enough. I hope I'm wrong! I really do.

Either way, please let us know how it works out after the room is finished and in use, and then again after full year has passed (all seasons), as that could be useful info for others following your thread.

I'd actually love to be wrong on this occasion!


- Stuart -

[spiraloutdrummer]

I was thinking the same thing about going through all the seasons and reporting back how it went. When the inner piece of glass was installed, it was cool and low humidity weather. So, if it is related to the moisture trapped in there, I might get lucky. It was late at night and I was rushing to get it done, so I did cut corners where I normally would not have. I am a bit of perfectionist myself and try to take the time through each step. The contractor moves fast when he is here and I get stressed and rushed to get things prepared in advance of him.

Erik

[spiraloutdrummer]

On to the door construction...
I enlisted the help of a friend. Thank goodness he knew what he was doing. We decided to go with two doors rather than the single super door just for dealing with the weight. We were going to get two pre-hung solid core wood doors, but the local hardware stores did not carry those in stock since everything is now steel, fiberglass, etc. So, we had to buy two solid core slabs and hang the doors ourselves. I would have had a hard time without the help of someone experienced at this. We added 1/2" mdf board to one of the doors to match the mass of the wall and window mass.

[spiraloutdrummer]

I purchased some heavy duty hinges online in anticipation of building a super door. We used the heavy duty hinges on the door in which we added the mdf. They were about $100 for 3 hinges and rated for up to 600 lbs. Overkill since we ended up with the double doors instead.

Erik

[spiraloutdrummer]

I bought the discontinued GM trunk rubber online as recommended in Rod's book and this forum for the seals. We stapled the thin leg portion of the trunk rubber to the back of the 1"x2" door stop lumber. It worked best when using lots of staples (spaced about every 1 1/2"). We closed the door with the door knob in place and pushed the door stop with trunk rubber attached against the door with some pressure and nailed into the jamb. Worked pretty well.

[spiraloutdrummer]

The heavy duty hinge dimensions are not designed for a standard door thickness, so the door with the heavy duty hinges was not flush with the wall, but inset a few inches. This made the standard door strike for the door knob not long enough. I am still looking for a door strike extender that works. All of the research I did discouraged using doors with holes for door knobs, but I really wanted to be able to lock and secure the room. I did not come up with a better alternative, so I installed locking door knobs.

[spiraloutdrummer]

I filled the space between the framing rough opening and the door jamb with wood, backer rod, and caulking. I now have both doors sealed on the sides and top. I ordered the automatic drop bottom seals that are surface mounted to the doors. I am waiting for them to arrive.

[spiraloutdrummer]

With the room completely empty and no treatments, I attempted some base line testing of the acoustics knowing that the results are going to be bad. I had a friend bring his mic, laptop, and speakers over. He had some software, but it was not REW. Here is a layout of what we did. 2 speakers blasting pink noise at 95dB, we moved the mic around to 4 spots in the room.

[spiraloutdrummer]

And here are the results. The software produced an average response I guess would be the terminology.

position1.jpg

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position4.jpg

[spiraloutdrummer]

I used the amroc room mode calculator. Since the room has a nook on one side, I used the longest room dimension on that axis. Then I got the results again using the majority room dimension on that same axis. Here are the results.

Erik

amroc_longest dim_Page_1.jpg

amroc_longest dim_Page_2.jpg

amroc_longest dim_Page_3.jpg

amroc_majority dim_Page_1.jpg

amroc_majority dim_Page_2.jpg

amroc_majority dim_Page_3.jpg

[spiraloutdrummer]

I have to admit that I do not understand how to use all of that information to help me plan out the acoustic treatments. I do know from the research that I need corner bass traps (with plastic to reflect back the highs), a bunch of broad band absorbers, and some ceiling clouds (possibly hard backed hung at a 12 degree angle). I will get working on that now and then get my friend to help me re-test using the REW software and compare the results with the first attempt at getting the acoustic treatments where they need to be.

Erik

[Soundman2020]

The software produced an average response I guess would be the terminology.

I've been trying it figure out what on earth those graphs are showing, but I have to admit that I don't have the faintest clue! The axes are not marked with the units that they are mesuring, clearly neither of the axes is logarithmic, and while I could guess that the X axis might be showing frequency (it runs from "100" to "1400" units), I can't for the life of me imagine what the Y axis might be showing: What on earth could measure between 400,000 and 4,000,000 units, in acoustics????

Even if the X axis is frequency, the graphs are no use since they don't go down anywhere near low enough: most of the interesting stuff happens below 100 Hz. And apart from anything else, those seem to be simple amplitude graphs, which don't tell you very much useful info about the room. You need graphs that show you what is happening over time, what happens to each amplitude at each frequency as time advances, such as waterfall plots, decay plots, spectrograms, and suchlike. That's what is important.

So unfortunately, the info in those graphs is meaningless and useless.

He had some software, but it was not REW.

Well there's your problem, right there!

... and then get my friend to help me re-test using the REW software and compare the results with the first attempt

sorry, but you cannot do that! You cannot use two different software packages to compare measurements! The only way that would work is if one of them is able to export an actual impulse response file, and the other is able to import that file (REW can do both). You would also have to get your mic and speakers back to the exact same location for the second test (accurate to within millimeters), and have the exact same settings on the audio interface and computer. There can be no differences at all. If the mic is not in the same place, or the settings are different, then you cannot validly compare the two sets of data. Each set will be valid for the location where it was taken, but it would not be possible to compare the two, so you'd never know if your treatment is working correctly or not.

Do yourself a favor, and get REW onto your own computer, with your own mic and your own speakers, then do the tests with that. REW gives you all the data you could possibly want, and plenty more besides. And since you'll be testing the room multiple times as you move forwards, with each new pieces of treatment, you can't really expect your friend to come over every time you need to run a new test to see how your devices is performing!

- Stuart -

[spiraloutdrummer]

Yeah we were pretty lost and confused. This is the part of the process in which I have the least understanding. I'll get the mic, interface, REW installed. I have some powered speakers available. I don't understand how I can get the mic placed into the same position within millimeters each time I test. Can I start with some corner bass traps already installed, or do I have to remove what I have started to get back to a completely empty room?

Erik