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Hestoft
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Joined: 11 Jul 2010
Posts: 39
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 Posted: Thu Jul 22, 2010 5:18 pm Post subject: Suggestions for acoustic treatment for floor and desk? |
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I have a 8' x 12' office I have converted into a studio. Unfortunately it has a concrete floor and seems to have a "bass bump" at around 60Hz to 70Hz, right where I am trying to record. In addition, most of the ambient noise coming in seems to be very low frequency.
I plan on adding more bass trapping triangles to the top corners where the walls meet (and where my SPL meter tells me the bass "lives"), but I am wondering if there is anything I can do on the floor and on the 8' Ilkea particle board kitchen counter that I use as a desk to further control low frequency rumble. The counter is on angle irons screwed into the wall studs, but with rubber between the angle iron and walls to dampen vibration.
Any suggestions would be most appreciated, as I am very close now with the acoustics and just need to tame the bass.
Ralf-Finn Hestoft
The NEW(ly contributing) Voice of Chicago |
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Lance Blair
M&M
Joined: 03 Jun 2007
Posts: 2281
Location: Atlanta
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| Posted: Thu Jul 22, 2010 8:34 pm Post subject: |
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You can cut the frequencies below 80Hz, and certainly kill anything below 60Hz either with a HPF or post-recording with your software.
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Skype: globalvoiceover
and now, http://lanceblairvo.com the blog is there now too! |
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Jacob Ekstroem
Club 300
Joined: 28 Oct 2007
Posts: 317
Location: A padded room with no windows somewhere in Scandinavia
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| Posted: Fri Jul 23, 2010 4:43 am Post subject: Re: Suggestions for acoustic treatment for floor and desk? |
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| Hestoft wrote: | | I have a 8' x 12' office I have converted into a studio. Unfortunately it has a concrete floor... I am wondering if there is anything I can do on the floor... |
A carpet, perhaps? 
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Jacob - Danish Voice Overs (try it... it sounds really funny, too!) |
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Mike Sommer
A Hundred Dozen
Joined: 05 May 2008
Posts: 1222
Location: Boss Angeles
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| Posted: Fri Jul 23, 2010 8:44 am Post subject: |
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The problem is you are against the wall; you've made another corner with the desk.
By being against the wall, you're more than likely right smack dab in the middle of a frequency peak. Moving your listening and recording position 38 percent into the length of the room, should offer the best compromise for any peaks and nulls in any size room.
Also understand the desk will resonate too. If you must record at a desk the top should be dense heavy wood 1-1/2 to 2-inches thick. Monitors if set on your desk should be set on foam insulators to reduce resonance, and don't put glass on the desk.
You also mentioned low frequency ambient noise. What are you hearing, where or what is it coming from?
Pet peeve:
This is not radio folks. This is Voice Acting. Get up out of the chair, get a cheap copy stand, a good mic stand. Stand up, and act. This gets you into the action and away from the walls, and up off the floor.
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The Blog:
http://voiceoveraudio.blogspot.com/
Acoustics are counter-intuitive. If one thing is certain about acoustics, it is that if anything seems obvious it is probably wrong. |
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Hestoft
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Joined: 11 Jul 2010
Posts: 39
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| Posted: Fri Jul 23, 2010 9:11 am Post subject: |
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Thanks for the replies! I do have two layers of carpet and an AudioMute sound dampening cotton mat on the desk and my monitors are on Primacoustics stands.
I think you are correct that I am in a frequency peak where I record and yes I was trying to be lazy and sit and record in front of the computer! You caught me. In my defense, I AM 6' 8" and my ceiling started at 7' and got lower with the multiple layers of Green-Glued drywall and sound deadening panels.
I also find in testing the room with my SPL meter, that the sound level of the bass frequencies rise significantly the closer I get to the ceiling. I had tried to set up a standing recording space away from the desk toward the left wall, but the house has steel reinforcement beams there and they caused some hum. I have since grounded the beam AND added an earth ground to my circuit box (thanks to info here in another post) so the buzz is lessened.
If I am correctly reading what you are saying about frequencies and spaces in the room, I should be recording in the middle of the room (from left to right) and about 38% off the wall with the desk?
I am getting delivery of the last of ATS's 4" 705 substitute, and plan on making two 48" bass traps by cutting 2' x2' sheets diagonally into triangles. (as shown in yet another informative post here) and placing them between the ceiling and the walls above the desk (centered) and on the wall to the right of the desk. I already have 1' triangular traps along the left wall. In addition, I have two GKS traps upright covering the corners to the left and right of the desk, as well as two RealTraps Bare Traps along the wall dead center on the desk. James at RealTraps also suggested some more Bare Traps on the walls left and right.
So, I have the following questions:
1) Will my placement and use of the 2' triangular traps be OK, or should I more them or use 1' triangles (only 4' or space exists on the wall above the desk due to the angled traps on the corners)?
2) Where is the idea place to record from?
3) Given that I really need to leave a patch of the ceiling above my recording area uncovered so I can actually stand up  , should I try and treat the surrounding ceiling as well, since the bass level rises toward the ceiling, or just hope the added panels will work? Naturally, I will test things with the meter after I install the triangles later today.
4) Where would be the best place for two additional Bare Traps?
After I do all this (hopefully based on your advice), I will return here with an update, and a sound file of the ambient noise.
Thanks again for all the GREAT advice!
Ralf-Finn Hestoft
The NEW(ly contributing) Voice of Chicago |
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Jacob Ekstroem
Club 300
Joined: 28 Oct 2007
Posts: 317
Location: A padded room with no windows somewhere in Scandinavia
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| Posted: Fri Jul 23, 2010 9:17 am Post subject: |
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I love the smell of geekiness in the morning.
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Jacob - Danish Voice Overs (try it... it sounds really funny, too!) |
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Mike Sommer
A Hundred Dozen
Joined: 05 May 2008
Posts: 1222
Location: Boss Angeles
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| Posted: Fri Jul 23, 2010 9:33 am Post subject: |
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This Geeky smell will have to linger into the evening 'cause I'm off to another jam packed SoCal day.
Ralf
Your project now is to post some pictures of your recording area so I can see what's going on.
And as I've asked you before; explain what you did with the ceiling and drywall and sound deadening panels -- it sounds curiously wrong for some reason. Draw a picture if you must.
Out of here!
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The Blog:
http://voiceoveraudio.blogspot.com/
Acoustics are counter-intuitive. If one thing is certain about acoustics, it is that if anything seems obvious it is probably wrong. |
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Mike Sommer
A Hundred Dozen
Joined: 05 May 2008
Posts: 1222
Location: Boss Angeles
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| Posted: Fri Jul 23, 2010 11:38 am Post subject: |
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Had a quick break and thought I would get to this.
| Hestoft wrote: | | I think you are correct that I am in a frequency peak where I record and yes I was trying to be lazy and sit and record in front of the computer! You caught me. In my defense, I AM 6' 8" and my ceiling started at 7' and got lower with the multiple layers of Green-Glued drywall and sound deadening panels. |
Not an excuse I'm 6'6" get a stool.
| Quote: | | I also find in testing the room with my SPL meter, that the sound level of the bass frequencies rise significantly the closer I get to the ceiling. I had tried to set up a standing recording space away from the desk toward the left wall, |
SPL is probably picking up the wall resonance. And what tones are you using to test the room. The problem is the SPL meter is not giving you an accurate picture.
| Quote: | | but the house has steel reinforcement beams there and they caused some hum. I have since grounded the beam AND added an earth ground to my circuit box (thanks to info here in another post) so the buzz is lessened. |
Disconnect that ground immediately. That is a fire hazard.
If you need to ground that beam, it need it's own grounding rod. this grounding rod needs to be at least 20-feet away form the the power service rod, so interaction does not occur.
Learn about grounding here: http://www.vo-bb.com/phpBB2/viewtopic.php?t=10782&postdays=0&postorder=asc&start=0
And what kind of equipment are you using that you're pulling a hum off a steel beam?? Check the ground service of your outlets, I bet you have a short. Or your ground at the service was gone and you just grounded to the house.
Pulling RF? Use Quad 4 Cable for your balanced lines.
Getting Hum? Check your ground at the service. Then work backwards until you find the problem.
| Quote: | | If I am correctly reading what you are saying about frequencies and spaces in the room, I should be recording in the middle of the room (from left to right) and about 38% off the wall with the desk? |
There about, yes. If your room is properly treated you have a little more room to move around, but the sweet spot in most rooms is 38% off the length of the room. Never in a corner, never against the walls.
| Quote: | I am getting delivery of the last of ATS's 4" 705 substitute, and plan on making two 48" bass traps by cutting 2' x2' sheets diagonally into triangles. (as shown in yet another informative post here) and placing them between the ceiling and the walls above the desk (centered) and on the wall to the right of the desk. I already have 1' triangular traps along the left wall. In addition, I have two GKS traps upright covering the corners to the left and right of the desk, as well as two RealTraps Bare Traps along the wall dead center on the desk. James at RealTraps also suggested some more Bare Traps on the walls left and right.
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Good start. I find that Basstraping in the corners is by far the most important thing. I like to be consistent with the basstrapes, i.e. if I use supper-chunks in one standing corner then I use it in all the standing corners.
In Marc Cashman's booth (on the production side of the wall) I made kind of a modified supper-chunk along the ceiling with 6-inches of rigid insulation on the face and the filled the back with all the scrap insulation from the build. It had a very nice effect on the sound in that room, along with the 4-inch soft ceiling I put in that room too. You can see it being roughed out in this picture:
| Quote: | So, I have the following questions:
1) Will my placement and use of the 2' triangular traps be OK, or should I more them or use 1' triangles (only 4' or space exists on the wall above the desk due to the angled traps on the corners)? |
I'm not quite following. So I'll just say that the wider the face of the trap the better. But, in most situations a 2-foot wide face is enough. Whether it is a supper-chunk type bass trap or a stacked 2'x4'x6" panels in the corners.
| Quote: | | 2) Where is the idea place to record from? |
Use your ears. The best place to start is 38% off the length of the room. Move around the room while talking. It you listen very carefully you can find a sweet spot where it is just your voice and nothing else. I did this for the lovely Amy Snively and her sound improve 100%. But it's best to get the room dialed in first.
| Quote: | | 3) Given that I really need to leave a patch of the ceiling above my recording area uncovered so I can actually stand up , should I try and treat the surrounding ceiling as well, since the bass level rises toward the ceiling, or just hope the added panels will work? Naturally, I will test things with the meter after I install the triangles later today. |
Well, you're going to need to sacrifice a little here. everyone needs a Cloud Trap above there listening space and recording space. 4-inches thick with at least 4-inches of air gap- or as much as you can get.
| Quote: | | 4) Where would be the best place for two additional Bare Traps? |
I assume you are referring to broadband panels. I would say every where, floor to ceiling. The image I posted above explaining 38%, is a very good start.
Here are my proposals for the Don LaFontaine VO Lab
Here are some small studio treatment optons:
| Quote: | After I do all this (hopefully based on your advice), I will return here with an update, and a sound file of the ambient noise.
Thanks again for all the GREAT advice! |
I think the best thing to do is stop what you are doing, and work out a plan of attack. If you need help contact me. Otherwise you're just taking what you know, and a lot of what you don't know and kind of scattering it around in freeform fashion and not really making any headway, all the while spending a lot of money.
Also put that SPL meter in the drawer. It's not telling you anything; we know bass terminates in corners and the walls resonates. Listen, use your ears.
If you go through all my post on this matter, you'll find that I state that in recording spaces under 1500 cubic feet, they require 80 to 90% of the wall space needs to be cover with 2 to 4-inches of rigid insulation treatment. This will eliminate room resonance and bring the decay time down to acceptable levels. As I have found, the smaller the room, the more treatment it needs.
_________________
The Blog:
http://voiceoveraudio.blogspot.com/
Acoustics are counter-intuitive. If one thing is certain about acoustics, it is that if anything seems obvious it is probably wrong. |
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Jacob Ekstroem
Club 300
Joined: 28 Oct 2007
Posts: 317
Location: A padded room with no windows somewhere in Scandinavia
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| Posted: Fri Jul 23, 2010 2:35 pm Post subject: |
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Amazing how much you're able to manage in "a quick break", Mike!! 
_________________
Regards,
Jacob - Danish Voice Overs (try it... it sounds really funny, too!) |
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Hestoft
Contributor
Joined: 11 Jul 2010
Posts: 39
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| Posted: Fri Jul 23, 2010 3:01 pm Post subject: |
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Well, let's see if I can figure out how to upload photos to this forum...
Ralf-Finn Hestoft
The NEW(ly contributing) Voice of Chicago
Last edited by Hestoft on Fri Jul 23, 2010 3:13 pm; edited 1 time in total |
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Jacob Ekstroem
Club 300
Joined: 28 Oct 2007
Posts: 317
Location: A padded room with no windows somewhere in Scandinavia
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| Posted: Fri Jul 23, 2010 3:09 pm Post subject: |
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Ralf, the [IMG] code will only work with filenames with picture extentions - jpeg, jpg, gif and similar. It won't work with tiny URL's
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Regards,
Jacob - Danish Voice Overs (try it... it sounds really funny, too!) |
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Hestoft
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Joined: 11 Jul 2010
Posts: 39
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| Posted: Fri Jul 23, 2010 3:16 pm Post subject: |
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Thanks for that Jacob! What size do people normally post? It looks like 1600 pixels is a bit wide, at least on my monitor.
Oh well, here are a couple more.
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Ralf-Finn Hestoft
The Great Dane |
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Jacob Ekstroem
Club 300
Joined: 28 Oct 2007
Posts: 317
Location: A padded room with no windows somewhere in Scandinavia
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| Posted: Fri Jul 23, 2010 3:29 pm Post subject: |
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Holy crap! It's the water-thingy from "The Abyss"!!!!  .gif" alt="W00T" border="0" />
_________________
Regards,
Jacob - Danish Voice Overs (try it... it sounds really funny, too!) |
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Hestoft
Contributor
Joined: 11 Jul 2010
Posts: 39
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| Posted: Fri Jul 23, 2010 3:29 pm Post subject: |
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One last post and then I will let the experts digest. Don't hate me Michael, but my Phonic PAA2 analyzer just arrived via UPS this morning, and it is giving me some interesting readings.
Sitting in the middle of the room with only the computer on, I am getting 55db of ambient noise. However it is ALL at below 80Hz, except for a band at 20,000Hz (which I think may be my monitor, which I could hear when I moved the 416 to close to it.
As to taking your advice to "use my ears," it is somewhat difficult for me since I have an acoustic neuroma that has caused a 50% hearing loss in my left ear, especially at the high frequencies. So, unfortunately, I can't really trust my ears to give me the full story on what is happening, which is why I have the meter and why I asked others for help in picking mics!
Thanks so much for your amazing insights into studio design and build and I am really sorry I did not contact you first. Now, however, I have to live with the results and am just trying to figure this out so I can get on with recording. I really appreciate your taking the time to help!
Here is a just-recorded "sounds of silence" WAV file of the ambient noise in my studio. It was recorded on the Neumann BCM-104 straight into my SPL Channel One without any low cut. http://db.tt/SH82LP[url]
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Ralf-Finn Hestoft
The Great Dane |
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Mike Sommer
A Hundred Dozen
Joined: 05 May 2008
Posts: 1222
Location: Boss Angeles
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| Posted: Fri Jul 23, 2010 7:01 pm Post subject: |
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| Jacob Ekstroem wrote: | | Amazing how much you're able to manage in "a quick break", Mike!! |
Should seen me when I was younger.
Let me digest this. I see some problems.
I got an 'Oops Error" On your audio file.
Just email it to me
MikeSommerVO at Gmail DOT com
_________________
The Blog:
http://voiceoveraudio.blogspot.com/
Acoustics are counter-intuitive. If one thing is certain about acoustics, it is that if anything seems obvious it is probably wrong.
Last edited by Mike Sommer on Fri Jul 23, 2010 7:06 pm; edited 1 time in total |
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