Corner with Panel trap or bass trap?

Can someone give me an idea whats the difference of Panel traps and Bass traps? I am confused, because i´ve read that Bass traps need to be diagonally in the corners, and I found a Ethan reply saying the best way to treat a corner with Panel traps is to put one on each wall as close as possible to the corner. Since my control room is kind of small small (4.5 x 5 meter), and I use it also for tracking acoustic guitar and vocals, I need to keep more free space as possible. My first idea was to have bass traps diagonally on the corners with 4.7"/120 mm of thickness. This would take alot of space! Besides I need one of the corners to be the spot for tracking vocals! So I wonder, if panel traps are the way to go? Thanks

Aloha Filete, Any chance you could please:

Edit your profile to include your location. This is very important, because this is a worldwide resource, and as such, material costs and availability vary widely. For example, masonry is cheaper than gypsum in some parts of the globe, whereas it's the exact opposite in other regions.

(from the forum "Before Posting" guideline) Thanks! :wink:

i´ve read that Bass traps need to be diagonally in the corners, and I found a Ethan reply saying the best way to treat a corner with Panel traps is to put one on each wall as close as possible to the corner.

Have you considered placing the bass traps along the ceiling corners (thus saving the much needed floor space, and then the panel traps as described by Ethan, if necessary? See pics at bottom of page: http://johnlsayers.com/phpBB2/viewtopic ... highlight= If this is a viable option, you might want to consider that while it may go without saying, I would be remiss if I were to not mention that it is no fun, let alone a major liability, if your traps happen to come down on yours/clients/friends heads, not to mention totally unacceptable. Be safe.

Besides I need one of the corners to be the spot for tracking vocals!

You might want to check this out: http://johnlsayers.com/phpBB2/viewtopic ... light=foam The point being, putting your vocals in a corner (especially if they are facing the corner) may not be the best thing to do/give the best results. Hope this helps. Aloha 8)

This means I can try to put one bass trap on each wall as close as possible to the corner? And instead of using 4.7"/120 mm of thickness (2 panels of 2.3"/60mm) for each wall there, I was thinking of using only half of the thickness (60mm), so only 1 panel, the density is 4.4 pcf/70 kg m3, so its quite good! I know that 120 mm, would be much better, but like I wrote before, I need space on that corner, and if I count to leave 1" or 2" air gap with a 60 mm panel, it pops-up a good thickness from the wall. Uh?

As soon as you follow the guidelines http://www.johnlsayers.com/phpBB2/viewtopic.php?t=3231 I'll be glad to answer your questions... STeve

knightfly wrote:

As soon as you follow the guidelines http://www.johnlsayers.com/phpBB2/viewtopic.php?t=3231 I'll be glad to answer your questions... STeve

Sorry, I´ve update my profile!

OK, we're getting closer; in that same link, there's a comment about acoustics being THREE-dimensional - I can give you a better idea of what you may need to do if you include the Height of your room as well as any odd shapes, like alcoves, columns, etc - if possible, a sketch would be best (or picture) - About traps - The term "bass trap" has been thrashed to death in this type forum, and seldom is it used correctly - a true "bass trap" would ONLY trap bass - examples would be the panel type traps like those on Ethan's site (the DIY ones, not the ones sold on the Realtraps site) - A panel trap works on a combination of panel resonance and the internal insulation, where the panel vibrates at resonant frequency and tries to move the air INSIDE the trap - the insulation mounted inside (not touching the front panel) tries to STOP the moving air, in the process turning some of the sound energy into heat as it tries to get through the small fissures/cracks between the glasswool or mineral wool fibers of the insulation. More energy is lost in flexing the front panel, so these traps are a relatively narrow band trap typically within an octave either side of resonance. They can be built to trap frequencies down to around 50 hZ with the right dimensions. Another type of resonant trap is the Helmholtz resonator, also known in one popular form as a "slat" or "slot" resonator. Types of helholtz resonators include "perforated panel" resonator, slat and slot resonators (one and the same thing), and "barrel" type resonators, not usually built that much. Helmholtz traps reportedly don't work well below about 100-150 hZ, but I'm not sure that couldn't be gotten around by proper placement and design. All resonant traps need to be placed at points of maximum sound PRESSURE in order to work best - this is NOT true of absorbent type traps. The point of maximum sound pressure at ALL frequencies in any room will be its tri-corners, because that's where all the boundaries come together, and a boundary forces a sound wave to STOP and turn around - therefore, it is a point of maximum sound PRESSURE and minimum sound VELOCITY. This means that resonant traps belong against walls and at specific points ALONG those walls depending on which frequency you're trying to treat. It also means that, since these traps are frequency-SPECIFIC, they are NOT a good "first thing" to do unless your room has absolutely HORRIBLE Length/width/height ratios that cause gross unevenness in frequency response. Which brings us to what a lot of people INCORRECTLY call bass traps - the BROADBAND absorber. I've even heard the term, "broadband bass trap" - if it's BROADBAND, that means it absorbs EVERYTHING, not just bass... Absorptive traps (broadband) - are typically made from 3 PCF (sometimes denser) fiberglass, mineral, or rockwool - higher densities tend to NOT give as even absorption as 3 PCF, although for corner traps up to maybe 6 PCF can work - this is partly because people are after more bass absorption usually when making corner traps, and because the trap surface ends up closer to perpendicular to sound waves when it's across a corner, so "grazing effect" isn't as noticeable (that's where a sound hits the panel at an angle OTHER than perpenducular - higher density materials cause more of this indirect sound to bounce off rather than be absorbed) I know corner traps take up space, but they are one of the best "first" things you can do to a room, for reasons mentioned above. Next, in roughly equal importance, would be sidewall absorbers (first reflection points), "clouds", or ceilng absorbers, and rear wall (deep) absorbers. Typical side/ceiling traps are 2 to 4" of absorbent placed an equal distance away from the wall, with NO BACKING - this mounting improves the bandwidth giving more even sounding treatment, without the additional cost of twice the material thickness. In a room that's less than about 18 feet long, diffusion is an "iffy" proposition in most cases - I've only heard a few people claim otherwise, and have seen/heard no proof that it can work. Carpeting in a room is rarely a good idea, unless you take the time to calculate each and every square foot of every kind of material in the room so you get an overall, even absorption coefficient at all frequencies - usually it's simpler to leave the floor hard (wood, concrete, vinyl, etc) and absorb the ceiling. You want some sort of absorption on ONE of each parallel pair of surfaces, or you'll get flutter echo. Some links - http://www.johnlsayers.com/phpBB2/viewtopic.php?t=4581 http://www.recording.org/ftopict-26889.html HTH... Steve

knightfly wrote:

...I can give you a better idea of what you may need to do if you include the Height of your room as well as any odd shapes, like alcoves, columns, etc - if possible, a sketch would be best (or picture)

Here´s a sketch of the space, I also made a pre-design using the software "Sketchup", I dont know if you can post that kind of files or if you are able to see it... Its not in the sketch, but there´s a closet along the wall that have the circle corner. Its a big closet with 4 glass doors. I will try to make some digital photos tomorrow, cos I´m waiting for the paint to dry... Thanks in advance! :)

What's the ceiling height just to the right of your (shown) ceiling window? And how far is it from there to the low wall? Steve

knightfly wrote:

What's the ceiling height just to the right of your (shown) ceiling window?

From the middle of the window is around 1.80 meter.

And how far is it from there to the low wall?

About 2.00 meter. Do you use Sketchup? If so, I can email you or post here the pre-design I made at scale. Ah, let me just say that I finally received my panels, and because in my country there´s only one factory that makes semi-rigid rockwool, and buying small quantities can take almost 2 months to deliver, I had to choose from what was ready in stock. So, I´ve just got: 12 panels of 3.5 pcf (56 kg/m3) with 1.5"/40 mm of thickness. 16 panels of 4.4 pcf (70 kg/m3) with 2.3"/60 mm of thickness. Maybe this info is helpfull to where/how to start. :wink:

I don't use sketchup, but I have the reader so you can post drawings here. The rockwool you got will be fine. I'm outa time for now, so please "bump" your thread so I'll see it when I get more time... Steve

OK, I am unable to post the SketchUp file, because its over 500k. I can email the file if you want it. Meanwhile, I´ve export some jpegs from Sketchup, to a better idea! This was made months ago, before I´ve started building the place, so the bass traps, broadband absorvers and sofa are just there as an possible example! I´am still confused how to deal with the 2 corners (circle corner, and the one behind the sofa)! Sure need bass traps there! I want to use the curtain, just to hide the closet. And closet will be full with studio stuff (cables, guitar cases,magazines, etc.) Also will I need some kind of ceiling cloud over the sofa? Let me know what do you guys think! Thanks :wink:

knightfly, where have you been these days!? :shock:

Steve's work schedule is pretty brutal -- two 12 hour days on day shift, followed by two 12 hour days on night shift, followed by three days off (technically two and a half days off). As such his time on the forum is sometimes intermittent, especially when he has other projects at home that demand his time. Hang in there. Chances are he'll see this soon and will have a chance to respond. It could be a few days though. --Keith :mrgreen:

Uff! :? Thanks for the info!

http://www.johnlsayers.com/phpBB2/viewtopic.php?p=18059 for ceiling height when setting speakers, use the height of the ceiling where the speakers will be located. That distance will be determined by length/width nulls in the Harmon spreadsheet, see the link. Placement will be the first step; then after it's sounding as good as it can, treatment to finish the job of smoothing out the response. Ceiling cloud - one method http://www.recording.org/ftopict-26889.html HTH... Steve

Hi knightfly! Thanks for the links, I will have a look, and let you know...

knightfly wrote:

http://www.johnlsayers.com/phpBB2/viewtopic.php?p=18059 for ceiling height when setting speakers, use the height of the ceiling where the speakers will be located. That distance will be determined by length/width nulls in the Harmon spreadsheet, see the link. Placement will be the first step; then after it's sounding as good as it can, treatment to finish the job of smoothing out the response.

Hi again, Here´s the room results I´ve got using the ceiling height of 1.80 meters (somewhere below the window) and the full length of the room (about 5.50 meters), or should I put only the length from the example speakers placement (from there to the low wall)? Anyway, to be honest, I´ve read the link you gave me about the room modes calculator and its too difficult for me to understand what to do with these results, so here´s the picture. Please, can you help me?

Placement will be the first step; then after it's sounding as good as it can, treatment to finish the job of smoothing out the response.

. I got that, its just I really need to have this studio room ready at the end of the month, still searching for building materials (pine, tools, etc), but I have this construction going a little slown, because I can´t figure out how I am gonna deal with the 2 corners (circle corner, and the one behind the sofa)! About the ceiling cloud, I know that example, looks good, I wanna make one like that for over the sofa spot! Thanks in advance for all the help! :)

Anyone?! :cry:

Just got off my last night shift, I'll see what I can do after I've had some sleep. Please "bump" this again so my name isn't last on the thread, that way I'll know I need to check it again... Steve

Here's a rough idea of what you should do to start; the pic explains most, all dimensions are to center of woofer (the dust cap) and should be used as a GUIDELINE, not God... Normally sitting that far back in a small room isn't wise, but your low sloped ceiling doesn't make things easier - in other words, anyone ELSE who has this exact size room please do NOT use this as a guide, or if you do please realize it may not work for you. Your other drawings show treatments in reasonable locations, but I'd treat that one corner with an angled absorber. You can also just put more absorbent up in front of the circular part at the rear, just treat it as another corner trap. Make another one for the opposite corner. The drape behind the couch should be more absorbent if possible - maybe a portable "screen" of thick absorbent you can move when you need access to the closet?? HTH... Steve

Normally sitting that far back in a small room isn't wise, but your low sloped ceiling doesn't make things easier

Yes! I know, but do you think from the sketchup drawings this is the best speakers placement option?

Your other drawings show treatments in reasonable locations, but I'd treat that one corner with an angled absorber.

Yep, I am going to make from floor to ceiling an angled absorber! But maybe to gain more space, instead of making with 60 cm width I was thinking of using 30 cm, so all the bass trap is more close to the corner. Is this acoustically wrong to do (smaller width)?

The drape behind the couch should be more absorbent if possible - maybe a portable "screen" of thick absorbent you can move when you need access to the closet??

Well, was going to get a strong wire, and hang a decorative curtain. I have no clue what kind of material could be absorvent and look like a curtain! Any idea?? Last, about the ceiling cloud, should I use 2" (5 cm) or 4" (10 cm) panels? Thanks in advance :wink:

Sorry, gotta get some sleep for now but just noticed I forgot to post the pic I marked up for you - more later... Steve

hum... I don´t think I can be sitting that far back, because I need some space there for the clients. So, from your drawing, I am afraid I have to move everything a little bit to the front...About 70cm to 1 meter. Is this going to make a BIG mess?!? Also, when you have time, can you please help me to get answers to the questions I´ve made before your last post? Thanks alot! :wink:

First, the orientation of your speakers is the ONLY way that room has a chance; anything else will positively SUCK. So, let's start working on getting your desk as far to the front (low side) as possible; for that, I need to know EXACTLY how far the center of your woofer is from the floor, when it's sitting on your speaker stand - if you're more comfortable with metric, don't convert; I'll do that if necessary. We're gonna try to get your speakers forward enough to be centered vertically at about 79-80% of your sloped ceiling height, if the speakers aren't too tall; I also need exact measurements of the speaker box, and distance from bottom of the box to center of woofer, bottom of box to center of tweeter, and depth of the box. Once we find a good spot for speakers, we can work our way back to you and the clients... Steve

Hi, knightfly I´m back! :D Sorry for the late reply, but I´ve been busy this last month, with all the studio furniture and acoustics building. Anyway, we just clean the studio room, and I am ready to give the measures you asked. For this I´ve used a workstation desk and drop a pair of Yamaha NS10M monitors in a vertical position using speakers stands. Here you have: * Woofer distance from the floor: 1.08 meters * Bottom of the box to center of woofer: 13 cm * Bottom of box to center of tweeter: 30 cm * Depth of the box : 18 cm If you need also the Width and Height of the NS10M, its 21.5 x 38 cm Ok, hope to have a reply from you soon, Thank you :wink: