Old 05-01-2007, 06:58 AM   #1
anytime732
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hi,

i am curious to know if the sound that i get from my monitor speakers (fostex PM2 mk2) is true enough to mix a good song on.

i do not currently have any bass traps or any other acoustic treatment, however i do have the walls and the ceiling covered in carpet. i also have a huge server rack where i keep my rack equipment and im not sure if that will be up setting the acousitcs of the room as it is a 6ft tall metal case basicly!! half of the height of the walls is made of breeze blocks and he top hald of the walls is made of wood.

if any one knows of any way to est or improve the quality of the acoustics in the room please comment.

a pic can be dfound here; http://a661.ac-images.myspacecdn.com...bcc8d42454.jpg
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Old 05-01-2007, 09:45 AM   #2
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ive been round the monitor issue too many times in my life.
soffits/desktops etc etc .
and i dont think there is a perfect solution no matter what one spends.
an engr in LA gave me the best advice cos i dont purport to be
a gold record mixer. as follows.
try to mix n check mixes on a variety of mediums.
earbuds/mono car speakers/home hifi's up to larger speakers if you can. and i feel he is right.
cos ive seen even good mixes break down on playing back on
junk speakers. which is unfortunately what a lot of consumers have. in summary a v difficult topic to address with no perfect solution imho.
my latest love for monitoring is a little curtis 20 buk
cd/radio/clock device to see if mixes dont work on it.

some people have told me thay like the new avantone brand for mixing. not exactly cheap but not very expensive. ITS A TOUGH TOPIC !
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Old 05-01-2007, 02:04 PM   #3
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hi,
i am curious to know if the sound that i get from my monitor speakers (fostex PM2 mk2) is true enough to mix a good song on.
The Fostex monitors are **OK**, but not great (IMO they suffer from a lack of inner/transient detail, and a fairly shallow front to back imaging), BUT . . . they should be good enough to get some pretty decent mixes on.

HOWEVER, from reading your description and looking at the picture, I can *guarantee* that your acoustics problems are BY FAR greater than any possible weakness in your monitors.

To give you a starting point, have a read of my post in this thread (I make a chunk of my living as an acoustics consultant):

http://www.cockos.com/forum/showthread.php?t=7794

The original query in that post was slightly different from yours, but the answers are actually very much the same. Between what I've detailed in that post and what is contained in the linked articles, this should give you a good starting point.

Quote:
i do not currently have any bass traps or any other acoustic treatment, however i do have the walls and the ceiling covered in carpet.
Using carpet all over your walls like this is a VERY imbalanced way to treat the acoustics of a room. Not that you should never use carpet for absorption, mind you . . .

The problem here is that carpet will only absorb high and mid frequencies, and it will not absorb low frequencies. Unfortunately, if you put in a whole bunch of high and mid frequency absorption without putting in equally as much low frequency absorption, you end up with an unnaturally dead, and MUDDY sounding room!

Quote:
if any one knows of any way to est or improve the quality of the acoustics in the room please comment.
In fact I DO know of a way to substantially improve the acoustics in your room!

The answer is bass traps . . . as many as you can afford to buy or build in your room.

While you can most definitely put too much high and mid frequency absorption in a room, it is pretty much impossible to put in too much low frequency absorption in a room, especially when we're talking about small rooms (i.e., the size rooms you find in a typical house or apartment).

This may seem counterintutive, but the fact of the matter is that the low frequency sound waves that are reflected off the room boundaries (walls, floor and ceiling) will cause acoustic distortion of the direct sound from your speakers by either enhancing (increasing the amplitude) or cancelling out (causing dips or even outright nulls in the frequency response) the direct sound waves coming from your monitors.

ALL rooms, and ESPECIALLY small rooms, need bass traps to get anything even close to a flat response. Most rooms will have peaks and nulls at numerous frequencies across the entire frequency spectrum having a range of a good 30 to 35 dB from top to bottom. If you address the room modes that cause the problems at those particular frequencies, you will not only reduce the amplitude (and also even out the decay time) of those problematic peaks, but also help to minimise or eliminate the dips/nulls. This means that, even though you are *absorbing* low frequency sound energy, you will actually be getting MORE bass (and and tighter, more accurate bass) than without the absorption.

So . . . it becomes a more than a little bit inconsequential to be worrying about whether your monitors are +/- 1 dB or +/- 3 dB of flat, if your room is acting like a huge filter/EQ that is skewing the frequency response of what you hear by 30 to 35 dB!

You will get more improvement (i.e., much greater accuracy) in that room by spending even $500-1000 (especially if you DIY) on proper acoustic treatment (i.e., broadband/bass traps, and balancing out the amount of high and mid frequency absorption so that you are not killing ALL the ambience in the room) than you will get in that room by spending even several thousand upgrading your monitors.

Another few articles that may be helpful to you:

http://www.realtraps.com/facts.htm

http://www.ethanwiner.com/acoustics.html

So . . . the short answer . . . fix your acoustics, and I wouldn't worry too much about your monitors until you treat the acoustics properly first.

Oh . . . and one other thing . . .

I would highly recommend getting those monitors OFF the desk, as I can guarantee you are getting some serious comb filtering from the sound reflected immediately from the speakers right off the surface of your desk. This will be skewing your frequency response, but it will also be playing havoc with your imaging.

I highly recommend to put them on stands, with the tweeters at ear height (or as close to it as possible).

Speaker stands should be as heavy and solid as possible, to avoid any low frequency resonances that could also cause your tweeters to move just enough to cause time smearing (which again mucks with your imaging).

The cheapest, easiest, and best solution for this I know of is to get a bunch of concrete breeze blocks and stack them up (you can glue them together with construction adhesive if needs be, to avoid instability and/or the potential that someone could bump into them and send the whole stack tumbling).

Concrete has a very low resonant frequency (somewhere down in the single digits) -- much lower than the lowest frequencies your monitors are capable of producing. This will give your speakers a very stable pedestal to work against -- this can also help tighten up your low end (as well as your imaging), because the speaker cabinet will not have the freedom to move ever so slightly when you get powerful kick drum hits -- which it can if you have your speakers sitting on unstable stands/furniture, or stands/furniture which might have a higher resonant frequency.

Hope that helps!

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Old 05-01-2007, 02:17 PM   #4
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Originally Posted by manning1 View Post
.
cos ive seen even good mixes break down on playing back on
junk speakers. which is unfortunately what a lot of consumers have.
Then they aren't good mixes. They are mixes that sound good on a particular set of speakers in a given room -- all of which is incredibly coloured if you don't have properly balanced acoustic treatment.

What most people do not seem to understand is that all rooms are essentially a filter . . . and especially small rooms . . . one big resonant comb filter.

Quote:
in summary a v difficult topic to address with no perfect solution imho.
The only thing close to a perfect solution is a well balanced monitoring system with excellent, properly controlled acoustics (and believe me there are a good many studios, even multimillion dollar studios that are putting out major releases, that have less than optimal acoustics).


I do agree that it is very helpful to have a couple of options for checking your mixes on different systems. But proper acoustics treatment can indeed make this much less of an issue. With properly balanced acoustics, you will generally find that your mixes will translate much better, and you can get your mixes to that point much more quickly, with less running back and forth to the car, etc., than with less than optimal acoustics.
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Old 05-01-2007, 02:33 PM   #5
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i was considering replacing my pm'2 with a set of krk rp-8s would that be a good idea seen as i am in a position to swap for free?
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Old 05-01-2007, 03:04 PM   #6
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i was considering replacing my pm'2 with a set of krk rp-8s would that be a good idea seen as i am in a position to swap for free?
Did you actually read any of the above?

Lots of good advise there that buying speakers wont change.

That said, try them out, if you like them better trade. Without first fixing the acoustics, the speakers wont help much.
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Old 05-01-2007, 06:12 PM   #7
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hi,

i do not currently have any bass traps or any other acoustic treatment
Ding! There's your problem.
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Old 05-02-2007, 05:17 AM   #8
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ok, ive spoekn to a friend who has the krk rp8's and i compared them to the pm2 and the krk sounded alot better and for a free swap i think it is worth the upgrade.......

as for the acoustic treatment, does anyone know of a way to build your own bass traps, i have looked at them on the net and for what they are they seem quite pricey i wonder if anyone knows where you can get the foam and shape it yourself that might beworth a try.........

i have found two types of tiles on ebay which i thinnk will do the trick just to calm the room down, et me know which ones you thiunk would be the best...

http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=320108479325

http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=320108104175
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Old 05-02-2007, 05:46 AM   #9
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Bubba's how to guide:

http://audiominds.com/forums/index.php?showtopic=3320

Forget about that foam stuff. It will do nothing for the low end and that is what usually needs the most help. And don't even think about using egg cartons.... that old piece of advice seems to pop up from time to time in these situations and egg cartons are just a bad idea.
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Old 05-02-2007, 06:33 AM   #10
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Anytime likes the KRK's cause he's heard mine, but I agree that also a lot of it is to do with room.

I moved my setup indoors for a bit and my mixes went all over the place, its amazing what a difference it can make.

Mixing at lower levels can compensate a bit whilst you sort out the acoustics.
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Old 05-02-2007, 06:38 AM   #11
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i must say that is a very impressive idea but..... my studio is not that big and if i where to kit it out with that size of traps here would be no room for me!!!!!

would it still have a significant effect if i where to 20"(width) traps on the between the ceiling and the walls as shown ( http://warsaw.innova-partners.com/~c...o/IMG_0284.jpg ) and then some pannels mounted flat on all four walls.........

i know that sounds a bit confising but would it have a good enough effect to justify doing it,,,,,,??
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Old 05-02-2007, 07:31 AM   #12
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Fill every corner you can (up and down, right and left, top or bottom) with rigid fiber glass, rockwool, or compressed fluffy fiber glass. Find every corner that is out of the way and fill it, or stradle it with at least 4" of the above. Hint; use the cieling corners to miantain your floor space. The back wall is reall an effective place to treat.

Put some absorbtion at your first reflection points. You can find these by using a mirror and a friend. Anywhere you can see a speaker in the mirror (your friend moves it around for you) from your listening position is a first reflection point. 2" of rock wool or glass will work.
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Old 05-02-2007, 09:03 AM   #13
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The foam panels you linked to are NOT bass traps. These will only absorb high and mid frequencies (and probably less effectively than the carpet you are using on the walls with this particular foam).

If you are going to use foam, you would need thick foam wedges to put in corners that are designed as bass traps, like these:

http://cgi.ebay.co.uk/2-off-3ft-Acou...QQcmdZViewItem

HOWEVER, while I am happy to see that this company (unlike a number of other companies selling cheap "studio foam" off ebay) provides certified lab reports, I can tell you from looking at their lab reports that the absorption specs on this foam is NOT very good, and you will be better building some DIY panels based on either Owens Corning 703 panels or the rockwool equivalent (i.e., same density) similar to Bubba's panels. I can assure you that these will be MUCH more effective, and will also have a much greater price/performance ratio.

There are a good many discussions on various forums about DIY 703/rockwool broadband/bass traps, with loads of interesting ideas and plans for building various types of frames for hanging these panels.

One good place to look (and ask) is Ethan Winer's acoustics forum here:

http://forums.musicplayer.com/ubbthr...tlist/Board/24

There's also the Sound on Sound "Studio Design & Acoustics" forum:

http://www.soundonsound.com/forum/po...=&Board=DESIGN

John Sayers' forum is good too:

http://www.johnlsayers.com/phpBB2/index.php

Quote:
Originally Posted by anytime732 View Post
i must say that is a very impressive idea but..... my studio is not that big and if i where to kit it out with that size of traps here would be no room for me!!!!!
Well . . . do you want accuracy or not? Low frequency room modes require mass, and a good amount of coverage, to address. Sorry . . . you can't defy the laws of physics!

It is very important to treat as much of your corner space as possible. You should start with the four vertical (wall/wall) corners, and then do the wall/ceiling corners

Any panels you mount flat on the wall should have a gap between the wall and back of the panel (I usually recommend about 3 to 4 inches).

This accomplishes a few things:

(1) it increases the low frequency absorption performance of those panels (i.e., the air gap causes it to act like a thicker panel), and

(2) it increases the amount of absorption surface that is usably exposed to the room.


Quote:
would it still have a significant effect if i where to 20"(width) traps on the between the ceiling and the walls as shown ( http://warsaw.innova-partners.com/~c...o/IMG_0284.jpg ) and then some pannels mounted flat on all four walls.........

i know that sounds a bit confising but would it have a good enough effect to justify doing it,,,,,,??
Yes, it would (though it will decrease the performance) . . . but it also adds to the difficulty in constructing the trap -- cutting fiberglass and/or rockwool is messy, itchy stuff.

I want to add another link that may be informative for you. To help you understand why it is so critically important to treat the corners of your room, read up on room modes and standing waves here:

http://www.isvr.soton.ac.uk/SPCG/Tut...ding-rooms.htm

This page has some excellent animations that show how low frequencies travel in a room, and demonstrates how all of the room modes gather in the corners. If you can interrupt the wave fronts at those corners, you will be able to reduce the amplitude of the reflected sound waves. Reducing the amplitude of these waves by even 6 dB in relation to the direct sound from your monitors will noticeably reduce the amount of acoustic distortion caused by the reflected sound interfering with the direct sound from your monitors.

Unfortunately for you, the smaller your room, the more you need bass traps!

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Old 05-02-2007, 09:18 AM   #14
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ok so using this method above http://warsaw.innova-partners.com/~c...ps/hanging.jpg to make bass traps wouldnot work and would be a waist of time even if used in the way this pic show????

http://warsaw.innova-partners.com/~c...ps/hanging.jpg
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Old 05-02-2007, 10:18 AM   #15
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The complete opposite. You DO want to do something similar to what I did. I would highly highly highly recommend filling all the corners at the top of your room as a starting point. My room isn't huge either. I mean, you aren't doing gynastics or kung fu practice in there, so you should be fine at the very least filling your top corners. Now, the reason I did panels versus filling the entire corner is a bang for the buck reason. You will get more low end extension, but the 4" thick panels alone will take care of 90% of the problem. The rest is gravy.

I am taking over another room in the house for mixing (Old lady ran off with some douche in Italy so I have the whole house to myself) and I am going to use the superchunk ( see here: http://forum.studiotips.com/viewtopic.php?t=535
) method in that room to really knock down the bass.
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Old 05-02-2007, 10:35 AM   #16
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ok so using this method above http://warsaw.innova-partners.com/~c...ps/hanging.jpg to make bass traps wouldnot work and would be a waist of time even if used in the way this pic show????

http://warsaw.innova-partners.com/~c...ps/hanging.jpg
Yikes! That's not what I was saying at all! Of course it would help (though it will NOT cure ALL of your problems).

Basically, getting at least SOME bass trapping in your room is going to be a lot better than having none!!

Perhaps this statement was confusing:

Quote:
Yes, it would (though it will decrease the performance) . . . but it also adds to the difficulty in constructing the trap -- cutting fiberglass and/or rockwool is messy, itchy stuff
What I meant by this is that cutting the panels down from a 24-inch width to a 20-inch width will give you less performance (and, to be honest, it probably won't save you that much space in the end). But even a 20-inch wide panel will certainly be better than NO panel there!
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Old 05-02-2007, 10:39 AM   #17
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but the 4" think panels alone will take care of 90% of the problem. The rest is gravy.
They can probably take care of 90% of the problem only if you have enough square footage of coverage to take care of 90% of the problem.

Just tossing up a four panels or so isn't going to be enough coverage to take care of 90% of the problem in most small rooms. Four panels will generally give you a tangible improvement, but you will still have some pretty big peaks and nulls unless you get more coverage in there.

Just want to make sure that's clear!
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Old 05-02-2007, 10:50 AM   #18
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They can probably take care of 90% of the problem only if you have enough square footage of coverage to take care of 90% of the problem.

Just tossing up a four panels or so isn't going to be enough coverage to take care of 90% of the problem in most small rooms. Four panels will generally give you a tangible improvement, but you will still have some pretty big peaks and nulls unless you get more coverage in there.

Just want to make sure that's clear!
Agreed. I only show 4 in my pictures (2 are really just mid/high absorbers and not bass traps), but there are probably 10 traps total in the room and 4 or so mid/high flutter killers.

My point is you don't need to get fancy in your design as a 4" thick panel is very effective... but cram in as many traps as you possibly can... start with top corners as that is wasted space anyway and won't screw up your ability to put in a desk or whatever. Then fill verticle corners if you still have room.
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Old 05-02-2007, 11:01 AM   #19
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Yep . . . agreed, BG.

I figured you were aware of this, but I just wanted to make sure that part of things didn't get misunderstood.
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Old 05-02-2007, 11:05 AM   #20
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I should also mention you want the traps to straddle corners rather than hang flush to the wall for bass trapping. The air space in the corners is the key here. Without depth behind the trap you don't trap as much bass. (Even better, fill the depth with more insulation, but as I said above, that is just gravy) I could go into 1/4 wave length explanations ad nauseum, but just know, you want to straddle a corner with your traps if at all possible. The next most desireable placement of a trap is 4" from the wall... but a 4" thick trap 4" from the wall loses 8" of space which is a lot... therefore I always recommend to start in the upper corners.
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Old 05-02-2007, 11:10 AM   #21
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Mixing at lower levels can compensate a bit whilst you sort out the acoustics.
Not as much as a lot of people like to think, to be honest.

It might help a little bit in that you don't hear the ringing for quite as long, but the ringing is still there . . . just quieter in *exact* proportion to the amount you've reduced the amplitude of the direct sound (this is one of the many reasons why some people incorrectly believe that EQ can fix modal ringing).

Mixing at a lower volume also doesn't do anything at all to fix modal nulls.

Further, while there are many entry level monitors that do a pretty decent job at more standard mixing levels, you lose a lot of detail and accuracy when you monitor to lower volume levels with most of these entry level monitors.
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Old 05-02-2007, 11:24 AM   #22
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The cheapest, easiest, and best solution for this I know of is to get a bunch of concrete breeze blocks and stack them up (you can glue them together with construction adhesive if needs be, to avoid instability and/or the potential that someone could bump into them and send the whole stack tumbling).
There is a new idea for me. I have known to get dense speaker stands, but to use cinder blocks is a great idea (and really obvious when you think about it). I just gotta figure out how to pretty em up though.

<slight hijack> What is your opinion of something like the Auralex MoPADs alone on a desktop or in conjunction with a proper dense speaker stand?

</end hijack>
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Old 05-02-2007, 11:47 AM   #23
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I should also mention you want to starddle corners rather than hang them flush to the wall for bass trapping. The air space in the corners is the key here. Without depth behind the trap you don't trap as much bass. (Even better, fill the depth with more insulation, but as I said above, that is just gravy) I could go into 1/4 wave length explanations ad nauseum, but just know, you want to straddle a corner with your traps if at all possible. The next most desireable placement of a trap is 4" from the wall... but a 4" thick trap 4" from the wall loses 8" of space which is a lot... therefore I always recommend to start in the upper corners.
Actually, there is more to it than that, as the behaviour of bass absorbers in corners involves somewhat more complex mechanics than just the 1/4 wavelength issue. Also, the most commonly discussed explanations (e.g., the explanation in Ethan's acoustics FAQ article) with regard to gapping traps from the walls only discuss a single angle of incidence, i.e., a direct wave front (at an angle perpendicular to the face of the trap and the wall), and don't go into detail about waves that enter the trap from other angles of incidence and are reflected back from the wall (and for good reason, because it's fairly complex physics, and beyond the scope of what Ethan's FAQ article is intended for). But that's a whole other 10 posts or so, and I don't want to add to the confusion for some who may be just wrapping their heads around some of this stuff for the first time!

One thing to be aware of is that the absorption curve of these kinds of panels change, depending on whether they are mounted in corners or mounted on a flat wall.

These kinds of panels tend to have an absorption peak right around the 100 Hz range, whereas the absorption peak (or peaks) of panels mounted on a flat wall tend to be in the 200 to 500 Hz range, and the absorption performance tends to roll off at a much higher frequency than for traps mounted in corners.

So, for dealing with room modes in the range of 175 or 200 Hz and lower, you will get the best performance with corner mounted panels. BUT . . . for dealing with room modes in the range of 200 Hz and above, you will tend to get the best performance with these types of panels mounted on a flat wall (or ceiling, etc.) with at least a 3 to 4 inch gap between the panel and the back wall.

If you take a look at the absorption curves on the RealTraps site (http://www.realtraps.com/data.htm), and you compare the absorption curve of corner-mounted MiniTraps to that of wall-mounted MiniTraps, you'll see what I mean.

Those lower room modes are certainly the most difficult (requiring the most mass and coverage) to treat, BUT . . . in many instances with small rooms, there are problematic room modes at more different frequencies, and often with quite a few different room modes (e.g., modes related to any or all of the length, width and height dimensions of the room) that are all stacked up at frequencies very near to each other, which can in effect create wider bands of peaks and nulls than those in the very low range.

Mind you, there is still a good deal of absorption in the 200-500 Hz and above range with corner-mounted panels, but sometimes in various rooms you may need to add wall-mounted panels to effectively address some of the worst problems in a room.

So . . . yes . . . by all means it's really important to treat the corners, and this generally needs to be a priority. But I want to take the explanation of the principles involved here to a more specific level, to emphasize the difference in behaviour of corner-mounted and wall-mounted broadband panels of the type we are talking about here.

Now . . . if you want to figure out at what frequencies the modal problems are most likely to occur in your room, you can use a program like ModeCalc (free download here: http://www.realtraps.com/modecalc.htm) or various online calculators to calculate the likely axial modes based on the dimensions of your room. HOWEVER, these predictions don't take into account the materials or construction methods used in your room that may (or may not) allow for a certain amount of transmission loss in your room. The only REAL way to get a good sense of where the actual problems are in your room is to use a program like ETF or Room EQ Wizard (http://www.hometheatershack.com/roomeq/), or other similar programs, to do a sine wave analysis of your room. Room EQ Wizard is a free download (you have to register as a member of their forum, but registration is free and there is no additional obligation). Actually, there are some discussions about DIY panels at the Home Theater Shack forum too, and Ethan is a moderator there as well.

Most people are utterly shocked when they run this kind of analysis in their room, because they find out that the frequency response of their room looks like the Swiss Alps! But if you never believed you needed serious bass trapping before, you'll certainly believe it after running this kind of acoustics analysis!

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Old 05-02-2007, 12:04 PM   #24
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There is a new idea for me. I have known to get dense speaker stands, but to use cinder blocks is a great idea (and really obvious when you think about it).
Cheap, too!

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I just gotta figure out how to pretty em up though.
I usually tell people they can just drape them in any kind of nice fabric that suits their decor. You can also paint them, but I'd think that draping them with fabric would be a more elegant solution.

Hehe . . . I recommended the cinder block option to somebody in a thread at gearslutz one time, and within about 8 or 12 hours of the time I had posted the suggestion (the guy was located in China, I believe), the guy had run out and bought some cinder blocks and sawed them all in half (to stack up the halves for 2 stands) . . . the dude sawed them with a HAND SAW, FFS!!! LOL. I was stunned!

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<slight hijack> What is your opinion of something like the Auralex MoPADs alone on a desktop or in conjunction with a proper dense speaker stand?

</end hijack>
For some situations, they may offer some improvements, but IMHO they are really not an ideal solution, because I feel they could still allow for a certain amount of (very miniscule) movement of the speaker that could give you some time smearing. But if you need them to isolate the speaker a bit from a desktop that is resonating like hell, and you need to get them up a little bit off the surface of the desk, or to angle the monitors down at you so that you'll be getting a little more "correct" angle of incidence from the tweaters to your ear, then I'd say they can certainly help a bit with these things if you don't have any other options . . . but there may be better solutions.

For example, it might be better to use a couple of concrete or marble, stone (or other heavy, dense material) slabs underneath the monitors than to use foam. But then again, it depends on how much of your problem is, for example, the result of an extremely resonant (and perhaps a bit wobbly) desk . . . you may need a greater thickness of concrete/stone, etc. than you want to risk stacking on that desk to get the isolation you need! Lead is another material that could work for that kind of isolation, but that can have its own drawbacks too (for the obvious reasons).

I think in the vast majority of cases you are best getting the monitors up on separate, heavy stands, rather than setting them on your desktop or a platform attached to a desk. If you have the monitors on separate, heavy stands, the MoPads aren't likely to offer any particular benefit (other than perhaps to angle the monitors down if that's needed, but in that case you are better to either build the stands to an appropriate height and/or make adjustments to your seating height, or use something else that's dense and heavy to introduce the angle).
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Old 05-02-2007, 12:10 PM   #25
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Thanks on the stands. Me thinks there is a trip to the lumber yard in my future.

Looking at ModeCalc, we want to use the axial modes... so looking at the table, which is that? They give 3 columns (one each under length, width, and height) and which numbers should we care about most?

EDIT: Dah, it was buried on the ModeCalc page. It seems modeCalc ONLY gives axial modes:

Quote:
When viewing the results look for an even spacing of the modes regardless of their color (good), and also look for multiple modes that occur at or near the same frequencies (bad). Also compare the ratios of the dimensions you entered with the recommended ratios, and compare your room's volume with the recommended minimum of approximately 2500 cubic feet or 70 cubic meters. Top

To make it easier for you to identify modes that are close together ModeCalc draws those mode lines taller, which simulates the larger response peak that occurs. The normal line height is marked with a thin gray horizontal line. When two modes are adjacent, or at least close, both lines are drawn taller. The closer the modes are to each other, the taller the lines appear. This also lets you identify modes that fall on identical frequencies. ModeCalc draws all the lines for one mode, then the next, and the next. So if several modes are at identical frequencies one line will hide the other. If you notice that an isolated line is higher than usual, that means there are at least two modes at that same frequency. You can then use the Frequency Table display to see them all. Also note that modes naturally become closer at higher frequencies. Therefore, having taller lines toward the right side of the graph is normal, and does not mean your room will really have that rising frequency response.
Any suggestions on speaker placement? If I remember correctly, you are supposed to put them so far from walls (38% something or other) and then your listening postion moves somewhere. Sorry to ask so many questions, but I think they are related to the original question and you are very knowledgable... I very much appreciate your explanations.
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Old 05-02-2007, 12:30 PM   #26
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GEEKS!

My room "treatment" consists of a bookcase to the left of my DAW desk, a KB desk to my right and amps and guitars piled behind me. Oh, my other treatment is a ceiling fan. Gives a nice swirly effect. EVERYTHING runs through a Leslie cab here! LOL!

Really, it ain't that bad. I only have 10'x10'. I monitor at pretty decent levels and also at conversation level. I do have to playback on a variety of systems before I put a "DONE" stamp on anything.

*sigh* Maybe someday I'll have more/better space(s) for my music hobby.

D
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Old 05-02-2007, 12:53 PM   #27
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I used to not care much until I did my little project and holy crap does it make a huge difference. Like insane. Now that I am a bachelor again, I can get away with whatever I want.

Nevermind on the speaker placement. Found the answer here: http://www.realtraps.com/art_room-setup.htm
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Old 05-02-2007, 01:13 PM   #28
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thanks guys, i think ive got all the info i need to get ris of most of my sound issues.

i will make a new post with some pics of the studio when i have made the adjustments........

are there any programs to test the acoustics in the room. i know it sounds wierd but there seems to be a program for anything these days so its probobly worth the ask!!!
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Old 05-02-2007, 01:17 PM   #29
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are there any programs to test the acoustics in the room. i know it sounds wierd but there seems to be a program for anything these days so its probobly worth the ask!!!
See Scott's post above. He links to a tool from Home Theater Shack.
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Old 05-02-2007, 01:24 PM   #30
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I'm no expert, but i'll mention that i went thru this process in my home studio awhile back. Adding several 2' x 2' x 2" rigid fiberglass panels made a remarkable difference in the tonal qualities of the room.

Highly recommended...

Here are a few pics to give you an idea. You'll note that i didn't mount 2" from the wall or across corners. I tend to monitor at low volumes, so i went the easy route.

Another thing i read on Ethan Winer's page was to stagger panels on opposite walls... panel opposite blank wall, blank wall opposite panel, kinda thing.











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Old 05-02-2007, 01:58 PM   #31
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Glad you found it helpful, guys.

Also . . . I edited my post above to mention that Room EQ Wizard is a free download (you have to register as a member of their forum, which is also free).

Just to add the obligatory caveat . . . Room EQ Wizard was actually developed for home theater types to help them use parametric EQ to *attempt* to address room modes, but it is important to understand that EQ is NOT appropriate way to deal with room modes for a number of reasons. I've made my points in the earlier linked post about why EQ is not appropriate or properly effective in addressing room modes, so I won't repeat it here!

But Room EQ Wizard DOES do a nice job of acoustics analysis, it's free, and it runs on Mac, PC and Linux, which is why I recommend it to people, and it also has a much nicer user interface and exponentially more user-friendly documentation than ETF.

Room EQ Wizard is indeed a *very* handy tool to have in the studio for numerous reasons.

And, among other things, you can also use it to make convolution impulses! (It even does the deconvolution for you, and all you have to do is export the impulse file as a .wav file.)
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Old 05-02-2007, 01:58 PM   #32
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Teej, what sort of fabric did you use? From the pics it looks like the stuff they put on the bottom of furniture to keep the cat out of the springs of the sofa. Also, how did you mount and hang your panels? While my method works, I am always looking for new and better ideas to apply to my stuff.
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Old 05-02-2007, 02:14 PM   #33
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Dang Teej! Your room looks niiiiiccceee! My wife would probably go along if I had a room treated and kept it looking that good. Alas, I am a slob... and SHE'S worse!

D

PS If I want her know I said the above... I'LL tell her OK?
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Old 05-02-2007, 02:51 PM   #34
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Scott,
The info you've provided is very helpful. I never did run a room analyzer, but my ears told me the treatment made a big difference.


BG,
Cool, huh? I stumbled across that material, and it turned out to be perfect for wrapping fiberglass. Yes, it's the fabric for use on the underside of upholstered furniture. And it was cheap!

I think it gives the panels a unique look...





D,
haha.. yeah, my wife just rolls her eyes everytime i tell her i've GOT to have this or that... but i catch her peeking into my studio and watching me play bass or drums and smiling, so life is good.

i learned early on that the girls tend to like drummers... heh.. still true today, my friend.


Oh! and your secret is safe with me.


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Old 05-02-2007, 02:54 PM   #35
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Girls dig drummers? I must be screwing up somewhere. I am usually the one when standing next to the guitar player and the girl is obviously annoyed as to why the hell am I standing there... "Oh, you are in the band? Huh... YOu mean, the band that just played for the past hour? Huh..."

I dig that fabric... looks very "industrial" and clean.
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Old 05-02-2007, 03:01 PM   #36
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Girls dig drummers?
Oh gosh, yes!

Here's a pic of me at my last gig... had to fight 'em off with karate... registered weapons, ya know. *sniff*




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Old 05-02-2007, 03:07 PM   #37
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This is an awesome thread. Just one question for Bubbagump though based on the traps he built, Doesn't the foil layer in the basstraps hinder the performance (if I observed correctly, the foil is facing into the room)?

At any rate, I think I'm going to make a trip to the lumber yard this weekend.

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Old 05-02-2007, 03:12 PM   #38
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No, it actually adds to the bass response. Note in my instructions I state specifically to remove the foil from certain places. It should only be on the surface facing into the room.

From Ethan Winer:

Quote:
For a given thickness, 703 is about twice as absorbent as acoustic foam at the lower frequencies, and it generally costs much less. Even better for low frequencies is 705-FRK, which is much more absorbent than 703 at 125 Hz and below. FRK stands for Foil Reinforced Kraft paper. This is similar to the paper that grocery bags are made of, but with a thin layer of metal foil bonded to one side. The FRK paper was not intended for acoustic purposes, but to serve as a vapor barrier in homes. It just happens to be good acoustically too. Be aware that the paper reflects mid and high frequencies when installed with that side facing the room; this may or may not be desirable for a given application. 705 is also available without a paper backing.
Full article here: http://ethanwiner.com/acoustics.html

The highs and mids were easy to knock down in my room with a few mid/high absorbers, so the little bit of reflection from the FRK in mid/highs was far outweighed by its benefit in the lows. At 125hz, 6pcf material with the FRK facing absorbs nearly 50% more than without.
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Old 05-02-2007, 03:28 PM   #39
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Thanks, just checking to make sure I saw what I thought I saw.

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Old 05-10-2007, 08:43 AM   #40
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How big is that room? It looks really tiny.. if it's *really* small, bass trapping is probably going to be fruitless.

IMO the big thing would be to try to get your speakers set in a symetrical way in the room -

- get that right monitor away from the side wall; get both monitors away from the back wall...

- then decouple the speakers from your desk somehow; the cinder block thing..

- then try to eliminate your closest reflective surfaces; that's a pretty big, flat desk, put some fluffy cloth over it..


Otherwise, in a tiny room you'd have to figure out exactly which frequency in the bass is dominant through analysis, and then build a custom-dimensioned Helmholtz resonator to stop it.


/ funny, I have old memory sticks laying on my desk as well?
// and change...
/// and my "second monitor" is up to the right (which is ergnomically bad IMO, but if I had an LCD it would be side by side)
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