timogiodeson MEASUREMENTS THREADS! Tracking Room Acoustic

NEW THREAD (ACOUSTIC FORUM) http://www.johnlsayers.com/phpBB2/viewtopic.php?t=10467 MEASUREMENTS & CORNERS EXPERIMENTS, HERE FROM PAGE 2 TO PAGE 7 Hello. I have a situation similar to the topic below: http://www.johnlsayers.com/phpBB2/viewt ... ng+started A small rectangular one room studio with piano, drum set , bass, recording equipment. this is a tracking and rehearsal room, I don't mix inside this room, accept for demos or simple stuff. Please check out the 2 D graphics in this page. I have a good amount of acoustic and construction materials in my storage.. : 15 cylindrical diffusers 2' wide 6' tall 5.1/2" deep 18 cylindrical diffusers 2' x2' x 5.1/2" deep 11 panels 4" tick 2x4, 8 pound density mineral fiber. 1 panel 4" tick 6x4, 2.5 pound density mineral fiber Also: 1 box of 2x4x2" 8 pound FRK mineral wool 3 moving blankets and a couples curtains 20 Lenrds Acoustic foam corner bass trap 2x1x1 37 Studio foam panels 2x2x2" and 3 metro diffusers. Additional 2 pound density foam 3 to 6 inc tick various sizes...about 60 sq. feet 2 box of acoustic tiles (the same I have on the ceiling) also: 2x4 and 2x1 studs, 1/8 plywood, poster board, etc... I temporarily removed all the acoustic material from the room accept for the ceiling. Treatment of the ceiling: (1 1/2" tick, painted mineral fiber ceiling tile on drywall, glue up mount , no air space, 100% coverage) "the NRC for this ceiling panels, if unpainted, and in 5/8" thickness, and drop ceiling mount is 0.55 ". The high density rigid mineral fiber is 0.61 x sqf. (the formula is 0.61 x 12 divided 5/8" thickness.)" rigid acoustic tile material. the same material it's also between the 2 layers of drywall see the sketch.. Ceiling slightly non parallel (just 4 inc) I removed most of the acoustic material because I'm not happy with the the sound and I decided to restart from scratch . This is a regular 2 leaf wall construction with 5/8 drywall on both side and 2 additional layers inside the room. Vinyl on concrete floor (street level) Walls: 100% coverage Drywall Ceiling: 100% Coverage ceilings tile on drywall Floor: 100% coverage vinyl on concrete There is a step in the floor... instrument placement require building risers and moving big instruments!...any suggestion will be appreciated.

there's not a lot of space :-) you probably have the right placement for instruments. i'd add corner trapping - including wall-ceiling corners. i'd also build a drum riser and some clouds for over the kit and perhaps over the piano. you can also build a couple of "polys" stuff with insulation to diffuse and absorber. a big slat over by the piano to keep things alive but deep enough to collect the bass happening over there. also a gobo to put in from of the bass amp. it won't stop it but it will force it to defract and get asorbed a bit.

gullfo wrote:

there's not a lot of space :-) you probably have the right placement for instruments. i'd add corner trapping - including wall-ceiling corners. i'd also build a drum riser and some clouds for over the kit and perhaps over the piano. you can also build a couple of "polys" stuff with insulation to diffuse and absorber. a big slat over by the piano to keep things alive but deep enough to collect the bass happening over there. also a gobo to put in from of the bass amp. it won't stop it but it will force it to defract and get asorbed a bit.

thanks for your input Glenn! yes... there's not a lot of space :cry: P.S about the ploys, I have many in my storage, but you said just a couple of them ... what size ?

here some more 2 D graphics: _________________

Aloha, Any chance you can crop your pics posts down to about 700 pixels wide to eliminate scrolling? This includes the "white part as well" (Forum rules) Thanks! :wink: Aloha 8)

kendale wrote:

Aloha, Any chance you can crop your pics posts down to about 700 pixels wide to eliminate scrolling? This includes the "white part as well" (Forum rules) Thanks! :wink: Aloha 8)

OK, I will try tonight, I just need to learn how to do it.... ........................................................................ .......................................................................... 1.33 am done!

Aloha, Great job! Thanks! :wink: Here's a basic layout idea. Aloha 8)

kendale wrote:

Aloha, Great job! Thanks! :wink: Here's a basic layout idea. Aloha 8)

Thank you Kendale! So... there is a concrete step in the floor...I will build two risers, one for the right leg and pedals of the piano , and one for the drum set , please see the atachment. 1) Do you have any suggestion for the risers/step situation..? 2) Where I should set up the speakers, computer rack and sub woofer? Quote: 3) I will need gobos or similar constructions between the instruments? and what kind of acoustic treatment you suggest for the walls/ceiling around the piano and drum and bass corners?

Aloha, Ahem! Watch that pic size :wink: Moving forward...

So... there is a concrete step in the floor...I will build two risers, one for the right leg and pedals of the piano , and one for the drum set , please see the atachment. 1) Do you have any suggestion for the risers/step situation..?

How high is that step? It would seem to be somewhat of a safety hazard to have to negotiate. Is it possible to pour an additional concrete slab throughout to even out the floor? I wouldn't recommend a floating or suspended floor due to a tendency to resonate at certain frequencies unless done right which is expensive!

2) Where I should set up the speakers, computer rack and sub woofer?

Ideally, in another room. :wink: This will help give you isolation you need to make critical decisions on mic selection and placement. If that is not an option and you are not mixing, where ever there's room and will not interfere with the musicians. If you are mixing, here are a few bits of information that I've collected along the way - • It is better to start with a longer front to back dimension than the side to side dimension because you don't want rear reflections to interfere • Speakers angled 30 deg. in from a flat wall result in speaker baffles being perpendicular to the two legs of equilateral triangle comprised of two speaker centers and a point about 10" behind your head • Monitors should NOT sit on the console but behind, placed on heavy decoupled stands - console placement causes early reflection problems in most cases, unless the console is slanted down in front a LOT. • Distance to wall behind speakers will change response drastically - there is a wall bounce calculator on the Acoustics forum that's fun to play with (needs Excel) • Moving either speakers or your head by as little as an inch or two can sometimes make drastic changes in response, due to modal peaks and dips. • Left/right room symmetry (at least within a foot or two of ear height) is important for good stereo imaging. • Roughly 38% of total room length from the front wall • Equilateral triangle formed by left, right mix position • Monitor angles 60 degrees • Monitor height – tweeters aimed at ear level (avoid mid point of floor to ceiling measurement – either sit higher or lower if necessary) • Angled side absorption panels – left/right of mix position • Side walls 6-12 degrees

3) I will need gobos or similar constructions between the instruments?

That depends on how much bleed you want in your recordings, but typically having a few gobos between the drums and the rest of instruments is common practice.

and what kind of acoustic treatment you suggest for the walls/ceiling around the piano and drum and bass corners?

I would start with 2' x 4' x 4" thick panels of 2.5 pcf mineral wool in all four corners - floor to ceiling. Next, try to break up the parallel wall surfaces with angled slat broadband absorbers. Finally, I would add several cloud absorbers (3"-4" thick mineral wool @ 2.5 pcf) over the drums & bass. Depending on how close you are miking the piano, you may be okay there. If there's too much bleed in the piano mics, perhaps a couple of gobos or the moving blankets will help. In a room this size, I would not use diffusion, especially around areas that are close to the mics due to comb filtering. I think you will find in this forum the majority of acoustic treatments calling for 3"-4" of fiberglass/rock wool/mineral wool @ 2.5-3 pcf instead of the typical foam products available. Hope this helps, Aloha 8)

How high is that step? It would seem to be somewhat of a safety hazard to have to negotiate. Is it possible to pour an additional concrete slab throughout to even out the floor? I wouldn't recommend a floating or suspended floor due to a tendency to resonate at certain frequencies unless done right which is expensive! Hope this helps, Aloha 8)

Thank you Jerry, yes, it helps! The step its about 3 3/4" high. I can make that high with two 2x4 studs plus a 3/4" plywood.. please take a look of the picture below, I made a little riser for one of the piano legs it is very small about 1' x 1' and doesn't resonate ....I just need one more for the pedals and piano bench eventually... Aloha, pour a concrete slab throughout to even out all the floor of the room will be to much for me I think... I don't know how to do that...also I'm renting... !! maybe a non permanent kind slab just under the drum and piano....? questions: About the acoustic materials in my storage: all my 2x4x4" panels are 8 pound density... :cry: I have only one 4x6x4" in 2.5 pound density... :) and then Foam and diffusion :oops: 4) For corners treatment, floor to ceiling ... 8 pound mineral wool (instead 2.5) or lenrds foam bass traps will be not an option? I have the material already... 5) Can you please post a link (if there is one...) with building instructions for the angled broadband slat you suggested ? thank you in advance . Here the piano riser,

More pictures: 8 pound density mineral wool in the corner, No good? should be 2.5 pound? Get rid of this??... :cry: ?

Here an experiment for the drum riser, 8 pound mineral wool in the floor next to the step...then plywood on top..."not in the picture" this really resonate like a deep bass drum, very loud! It's a musical instrument!!! :shock: No need for a bass drum ...just play the riser! :)

the 8lb in the corner is probably ok. the piano riser is clever! the drum riser - use multiple layers of something heavy like 1" (25mm) MDF - 3 layers or more to get the mass of it higher. criss-cross the panels and glue it. you'll want something under the part where plain floor is exposed - maybe a 1" layer of 3lb insulation.

thanks for your help gullfo, Sorry Gulfo and Kendale, I just realized that I don't need a drum riser :oops: ... I just need a small riser for the drummer chair similar to the piano leg riser... So, I guess problem solved. _________________ Thanks, P.S. This are my home made diffusers, and temporary vocal corner.

kendale wrote:

Aloha, Great job! Thanks! :wink: Here's a basic layout idea. Aloha 8)

Kendale, thanks for the layout , I experimented with it...but the drum doesn't sound really good in that corner there...and the piano sound better if toward the center of the room. I made two new room layout but I guess I'm done with this for now, eventually I will experiment again later. Just 3 more question please: 1) what size and coverage of angled broadband slot resonator I need for this room? 2) What slot size /thickness and space between slots for the broadband? 3) about the Ploys, how many and what size? thank y in advance.

B.D.R. wrote:

1) what size and coverage of angled broadband slot resonator I need for this room? just few small slots in each wall just like 2x4 panels? or all around the rom making angles? floor to ceiling?

it depends on the room modes. we can estimate based on the size what frequencies are most problematic, or you could measure the room (using Room EQ wizard or ETF for example) and we could determine what treatments you need - mode control, RT60, etc..

B.D.R. wrote:

2) " broadband " what slot size /tickness and space between slots for the broadband?

see #1

B.D.R. wrote:

3) Polys, how many and what size poly for this room?

in this case, you might construct polys across each corner of the room to add diffusion and broadband bass trapping. straddle the corners with the poly. leave the back of it open and line with insulation. seal the top and bottom. if you can go floor-ceiling, even better.

gullfo wrote:

it depends on the room modes. we can estimate based on the size what frequencies are most problematic, or you could measure the room (using Room EQ wizard or ETF for example) and we could determine what treatments you need - mode control, RT60, etc..

Thanks Glenn, about the room testing... I have NOT experiences in room testing, and I guess it can be very tricky.. I will be using home hobbyist equipment like radio shack sound level meter and the free download Room EQ wizard testing program. Anomalies in reading can happen all the times. With the new acosutic treatment nulls, picks, comb filtering will take place In different areas than now. This is a tracking room ...no listening position. Considering all this, do you think room testing is really necessary? please let me know thank you in advance

room testing is necessary... the Room EQ Wizard is quite good and with some patience you'll be able to make measurements in a variety of locations in the room to be sure your treatments are working... if nothing else, get a Behringer ECM8000 omni directional mic, the shock mount, and a stand with rubber feet. not much money and you'll be using it a bunch of times to tune your room...

gullfo wrote:

room testing is necessary... the Room EQ Wizard is quite good and with some patience you'll be able to make measurements in a variety of locations in the room to be sure your treatments are working... if nothing else, get a Behringer ECM8000 omni directional mic, the shock mount, and a stand with rubber feet. not much money and you'll be using it a bunch of times to tune your room...

I already have the omni ECM8000 mic ... I like it over drums... :) but I just got the Radio shack sound level meter... I need both? any ways Ill figure out... thanks

use the ECM with the REW software... make a floor layout and mark your test locations and save output files for each.

gullfo wrote:

use the ECM with the REW software... make a floor layout and mark your test locations and save output files for each.

OK, I will use the ECM I need to learn how everything works ..I will try in the next few days and than hopefully I will post the results. thank you

gullfo wrote:

use the ECM with the REW software... make a floor layout and mark your test locations and save output files for each.

Thank you Glenn, finally I can make measurement's , I'm using room EQ wizard and behringer measurement mic, also I'm using the spl meter for calibration. "behringer measurement mic to preamp, preamp output to sound card input. sound card output to Sub woofer input sub woofer output to speaker input. all flat Sub-woofer and speaker in the floor tri-corner, all flat. Guess all works, I made some measurement's already but I have two questions, 1) In my room there is no listening or speakers position, only instruments and microphones...I guess the best listening position will be where the room mics are, because I record almost everything from this mics.. but where the sub woofer and speaker goes? 2) What R.E.W output files you need exactly? thank you in advance. G. P.S. This is my final layout .

you want to look at the low frequency decay and waterfall, to determine what room modes you have. in general you'll want broadband bass trapping in the room but you'll want to find other frequencies which may need additional control. the goal being a neutral or balanced room that minimizes the impact of what you hear from either the instruments, or from your monitors. the other bit to check is your RT60 reverberation to get that to a level you're comfortable with. for testing purposes, the subwoofer and speakers in the corner is fine as it will excite the entire room. the mics for recording are one location to measure as well as each location someone will be sitting or standing to verify you have people in locations with minimal peaks or lows in the response.

ROOM MEASUREMENTS STARTS FROM HERE Thanks Glenn, I made all the measurements today... but the original files are about 3 Mb each, too big to post , I will post some JPG for now..

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