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Suggestions for treating this room?

I was wondering if anyone could offer advice to treat this room to record spoken dialogue:

http://i.imgur.com/bUnbZ2R.png

I'm hoping to record people at the table.

The room is roughly 23'x23' with a 98" ceiling.

The floor is fake wood laminate.

There is a popcorn ceiling.

Where the walls and ceiling meet, there is a corner molding kind of like this: http://i.imgur.com/hhMNwfv.jpg (but somewhat more irregularly shaped).

The windows have vinyl venetian blinds.

The double-door opening contains two french doors with glass panels.

The single-door opening contains a steel door.

The shelving (the grid and bookcase) contains a mix of books and other miscellaneous objects.

The two "boxes" in the room are storage cabinets.

Since I'm recording voice only, I'm thinking I might get away with using only 2-inch thick panels (2'x4' OC703 fiberglass)?

My straw-man plan (knock it down!):

- two panels on each section of wall between corners and windows (side by side to create 4'x4')
- four panels over the table (to create a 4' x 8' absorptive area)
- tilt the venetian blinds partially closed and rely on diffusion
- leave shelving exposed and rely on diffusion

Should I put panels on the doors? I'm guessing the double-doors would need it, maybe not the small entrance door (upper right)?

Could I get away with a single 2' x 4' panel on each wall section?

Do I need to worry about reflections off the table?

Any other thoughts?

Comments

Profile picture for user pcrecord

pcrecord Sat, 11/19/2016 - 06:29

komencanto, post: 443625, member: 50097 wrote: Since I'm recording voice only, I'm thinking I might get away with using only 2-inch thick panels (2'x4' OC703 fiberglass)?

I'm far from being an acoustician.. but 2'' thick will get rid of flutter echo and reduce natural reverb of the room but will also change the frequency curve of the room and suck out the highend..
It may not be what you want.

The first thing I would do is to record in the room while intact. Post samples if you want and let's find out what defects we are dealing with.
Second, what is the level of quality you are aiming ? Is it for radio, movies, audio books, or just for fun ?

Profile picture for user komencanto

komencanto Sun, 11/20/2016 - 19:27

pcrecord, post: 443626, member: 46460 wrote: I'm far from being an acoustician.. but 2'' thick will get rid of flutter echo and reduce natural reverb of the room but will also change the frequency curve of the room and suck out the highend..
It may not be what you want.

The first thing I would do is to record in the room while intact. Post samples if you want and let's find out what defects we are dealing with.
Second, what is the level of quality you are aiming ? Is it for radio, movies, audio books, or just for fun ?

I will get some samples.

It will be for a serial audio drama podcast, which for the most part is just for fun; but a not-insignificant amount of the satisfaction will come from having pretty high-quality audio. I have heard some audio dramas that stand up surprisingly well with sub-par audio quality but I'm not sure that mine would be among them.

Profile picture for user Brien Holcombe

Brien Holcombe Wed, 11/23/2016 - 07:26

You said "23'x23".

This is your biggest concern at the moment. Any room will have at least 1 pair of parellell walls that create flutter echo. With a square room such as yours, you have 2 pair that will produce flutter echo at the same frequency compounding your room sickness acoustically speaking.

I suspect the easiest out , since you did as about treatment, would be to hang a heavy drape or blanket about 8 feet from any wall that wouldn't confine you.

Ideally you would construct a new wall to eliminate the multiple pairs but only as an option if you really wanted a better defined acoustic environment.

Profile picture for user komencanto

komencanto Wed, 11/23/2016 - 08:06

I use this room for other purposes when not recording, so a permanent wall (that divides or drastically skews the room) is not an option.

I may be able to purchase some used acoustic panels, if I can talk the seller down a bit. He has:

12 4'x8' 2" AlphaSorb Wall Panels (rigid fiberglass)

20 4'x6' 2" AlphaSorb hanging baffles (flexible 2# per cubic foot fiberglass)

The panels were bought in 2012 from AcousticalSolutions.com .

Would it help either to hang the baffles from the ceiling, or to arrange the rigid 4'x8' panels on stands, at non-parallel angles while recording? I could take them down / push them up against a wall when not in use...

More generally, how might I treat the room with these? How many of each would I need and how might I use/arrange them?

Profile picture for user pcrecord

pcrecord Wed, 11/23/2016 - 10:56

First, be very carefull about using a bunch of 2 inches thick pannel without other formats. 2 inches material will affect only the higher range of the frequency Spectrum. Which may create more problems.

Without creating a new wall (which is a great Idea) you could fill a wall with a bookshelf with various items in it. It will give you some place to put stuff (who don't need to put stuff away) and will create a pseudo natural diffuser. if you place this bookshelf behind your mixing position, it will resolve a many problems.

Then I would test the room to hear how it sounds. if you still have flutter echo or other defects, use a combinaison of 2'' and bass trap panels.. You could build your own for not much money, there is many video on youtube.. I made mine to be removable from the wall with a hard back and I can put them on feets to use like gobos..
Treat the first reflections first, don't put your mixing place to a corner but with equal distance of the side walls..

Profile picture for user Brien Holcombe

Brien Holcombe Wed, 11/23/2016 - 10:58

General speaking . ..if you do not make an attempt to remove the multiple pairs of trouble making hard boundaries then you need to eliminate as much of the boundary as possible.

At this point you are not as much treating as you are trying to get ahead of the problem that does exist in your current configuration.

Profile picture for user dvdhawk

dvdhawk Fri, 11/25/2016 - 22:27

That's a big enough room to an old-time golden age of radio drama, with 10 voice-actors and live foley / sfx artists. (like this cheesy old gem)

If that's in your plans, it would make sense to me to buy a bunch of acoustical treatments and try to make this room sound more like a soundstage. If this is for 1-2 people doing spoken-word I'm not sure it's practical, but it's your party. Is there no smaller room you could use? There's a reason voiceover artists and radio DJs are in cozy booths. If this is the only room available, personally I'd try to make one small dry area 1/10th that size, even if it's just by limiting the room reflections with gobos - unless I'm missing the point ( which is always a strong possibility ) and you absolutely need 529 sq.ft. of performance space.

Profile picture for user komencanto

komencanto Sat, 11/26/2016 - 09:34

dvdhawk, post: 444302, member: 36047 wrote: Is there no smaller room you could use?

Ironically, my original plan was to build a 5'x8' room in one corner of this room to record in - but I was advised to treat the entire room instead. :)

I do have a ~ 10'x10' spare bedroom, but the 23'x23' room is more accessible/public.

Which would be the better room to start with, assuming it will:

- always be used to record 1 (maybe 2) people, voice acting;

- never be used to record music;

- never be used for listening on monitors, or for mixing (this will usually be handled by my friend/partner in another state, who is a professional music/audio editor and composer, and has better hearing than I do).

About the gobos - would it be possible to get good-to-excellent results if they were used in the larger room?

Profile picture for user komencanto

komencanto Mon, 11/28/2016 - 09:15

Here are the room acoustics audio samples @pcrecord requested.

The first half contains recordings in the large room (which I inquired about originally), and the second half contains recordings made in the small spare room I mentioned after @dvdhawk asked if I had a smaller space available.

These are made with a Rode NT1-A into a Zoom H4n. I recorded voice and some percussive sounds at recording levels 90%, 70%, 50%, 30%, and 10% in each of the rooms. I tried to keep the meter peaking at about -12.

Where to go from here? Is there a clear choice between the large room and small room as a starting point?

(PS - as someone new to this, let me just say that hearing your own mouth sounds at 90% is horrifying.)

[MEDIA=audio]http://recording.org/attachments/room-acoustics-samples-mp3.15729/

Attached files

room-acoustics-samples.mp3 (3.4 MB) 

Profile picture for user dvdhawk

dvdhawk Fri, 12/02/2016 - 22:37

I just listened to your test recording. Honestly, neither room sounds all that bad at 70% or 50%. At the 90% settings not only do we hear the dreaded "mouth sounds", but with that much gain I hear way too much of the room, and something running in the background. The sensitivity of the condenser mic probably isn't doing you any favors here either. If you have one, try a basic dynamic vocal mic (Shure SM58, or similar) for the sake of experiment and see how it sounds.

Something else that I don't think got addressed from your original post, yes, you might need to worry about a big reflective table in either room. Something as simple as a towel, blanket, or whatever you have will soften up that surface from sound reflections and help to quiet any sound of papers rustling.

Profile picture for user komencanto

komencanto Thu, 12/08/2016 - 10:44

So, I built this 7-foot bi-fold gobo and placed it in the large room as shown in the attached photo (with the bookcase behind me to act as a diffuser, as recommended by @pcrecord).

I did another set of sound test recordings and created three before/after MP3 files (also attached).

Even though my hearing is going, I'm pretty sure the recordings are noticeably better/cleaner with the gobo. I'm wondering if this might make it possible to record in the larger room... maybe I need to add some panels to the walls too?

I still have about 1/3 of a bundle of Roxul left - I might build a panel to hang on the short stretch of wall directly to the right of the seating position as show in the image...

I might build another set of these gobos too - it was actually kind of fun. I used dark grey felt for the fabric - the panels remind me of the Monolith from the opening scene of 2001: A Space Odyssey :)

[MEDIA=audio]http://recording.org/attachments/90pct-a-b-mp3.16334/

[MEDIA=audio]http://recording.org/attachments/70pct-a-b-mp3.16335/

[MEDIA=audio]http://recording.org/attachments/50pct-a-b-mp3.16336/

Attached files

50pct-a-b.mp3 (573.5 KB)  70pct-a-b.mp3 (589.8 KB)  90pct-a-b.mp3 (327.5 KB) 

Profile picture for user komencanto

komencanto Thu, 12/08/2016 - 18:15

@pcrecord, each audio file contains a before and after - the "before" first, the "after" second. They're recorded at 90%, 70%, and 50% of maximum input gain (according to the Zoom recording level control). I was trying to keep the meter at about -12dB for each recording, so the tone of voice and sound characteristics vary between files.

It seems in the 90% recording especially that some of the lower end "boominess" has been eliminated; and in the other recordings, the reverb from percussive sounds (snapping fingers and clapping) is considerably less in the second halves.

In addition, I just arranged to pick up six used 2-inch acoustic panels, 4' x 8', this weekend. I will trim them down to 6' and put them between the windows (I guess?).

Profile picture for user pcrecord

pcrecord Thu, 12/08/2016 - 18:41

It sounds very good already..
Be carefull not to thame the room too much, or give yourself the possibility to move them around or cancel them with hardboard.

This thread should be kept as reference because it shows that threating a room even just a little makes a lot of difference on the end result.
That's why I love RO so much. When the recommendations become results ! ;)

Profile picture for user Brien Holcombe

Brien Holcombe Fri, 12/09/2016 - 14:43

What would help would be pictures of what it is you are doing. I know what a square room will do, large or small, so I would like to see what it is that is happening when you are doing these recordings. My gut says you are isolating the mic from the room. But I would have to see it to know it.

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