Tuesday, July 24th, 2007
Recording & Producing Music at Home, Part 2: Fighting Even More Noise
In the previous installment of this series I discussed some of the very basic, low effort things you can do to improve the sound isolation of your home studio. This time, I will proceed to discuss some more drastic measures that you can take.
Please note that everything I discuss here primarily is about single room home studios (where recording occurs in the same room as production, mixing and mastering). If you plan on building a multi-room studio with separate rooms for recording this will require a considerably greater amount of effort, money, space and time. This usually means you are building the studio from the ground up or you are moving into a new house. I will therefore discuss multi-room studios in a separate, future article and keep this article limited to single-room home studios. In addition, please *always* consult any architectural changes you make and walls you build with a qualified professional (e.g. an architect) first. Failing to do so might result in significant damage to your property, or, even worse, to you.
Continuing from the weakest link principle as discussed in the previous article, the next level of sound improvement comes from reinforcing the weakest wall(s) in your studio. If you know from the building plans of your studio room that one wall is significantly weaker, you should focus on improving its sound isolation. The primary factor here is the thickness and material used for the wall: the lower the mass of a partition, the weaker its sound isolating properties. You should keep in mind that simply strongly reinforcing a single wall until it’s much stronger than the other walls will not do much for sound isolation of the lower mids and lows. Low frequency sound has so much energy that it will simply find a flanking path around the reinforced structure, negating all the effort you spent on reinforcing the wall. You should therefore try to bring it up to around the sound isolating level of the other walls.
The simplest way of reinforcing a wall is simply to add more mass to it. A lot of people recommend plasterboard (drywall) for this purpose, but these can be relatively easy to damage and therefore difficult to handle. A great alternative is high density MDF (or even better HDF, but this is more expensive), which is a lot easier to handle (MDF has a density of about 600-800 kg/m3, plasterboard usually around 800 kg/m3) and doesn’t damage as easily. If you want to be a little more adventurous, build a wall about 15 centimeters in front of the existing wall and fill up the cavity with rockwool. This should yield improved sound isolation over simply adding mass, but is also quite a bit more difficult to do (and it will also reduce the size of your room a bit more).
The next step up is completely overhauling your studio to improve its sound isolating qualities. This tends to be very expensive and might take quite a while. It’s really only recommended if you have some experience with building walls and the like, otherwise you’re better off hiring someone to do it for you. The best solution to isolate a studio is the room-within-room principle. This involves building a secondary room suspended within the existing room, resulting in a situation in which the inner room transfers a minimum of noise and vibrations to the outer room. Please keep in mind that the outer room should be optimized first! If the existing walls, ceiling and floor do not isolate well there really is not much of a point of building a room within them. Therefore, follow the previously given recommendations (at the beginning of this article and in the previous article) to ensure that the outer room will have at least some sound isolating qualities.
Once you have completed the outer room, I recommend using the plans as provided by the SAE institute for the inner room (http://www.saecollege.de/reference_material/titles/Acoustics3.htm). Keep in mind that when they refer to plasterboard or gypsum you may also consider using MDF if you don’t have experience working with plasterboard. These plans provided by SAE generally result in an STC rating of close to 60, which should be ample for the average home studio.
Please be aware that your room is now completely airtight. Try to consult a professional to install a low noise ventilation system sound isolating (low airspeed systems are best for this). If this is too costly, you should ventilate the room whenever you can and never stay within the studio with the doors closed for extended periods of time. If there’s demand for it I’ll discuss how to build a good ventilation system yourself in a future article.
An interesting phenomenon when improving the sound isolation of your studio is that, as the noise floor of your drops, other noises that you previously did not notice will become more salient. A clear example of this is the noise produced by the studio computer, which all of a sudden becomes a lot more noticeable in a really quiet room. This is why I will also include some information in this article on how to reduce the most common causes of noise generated from within a home studio. Key here is having a computer that does not generate a lot of heat. More heat being generated by your computer means there will be more noise coming from the computer fans and your studio temperature will increase. You should not be tempted to install the newest and latest computer components, these are usually also the hottest and both financially and technically least efficient. A cool computer will also be able to utilize more passive cooling solutions, which means less generation of noise by computer fans.
A great site for silent computing is http://www.silentpcreview.com. These people have a huge silence fetish and have very advanced testing equipment available. Because there is a lot of information on that site and you might not feel like reading all of it, I will give a quick overview of computer that is relatively fast, cheap and quiet (as of July 2007).
CPU: Current Intel Core2Duo’s are highly recommended. The C2D E6600 runs cool and is quite fast. If you really run a lot of plugins on your computer, consider the C2D Q6600. It runs hotter (so don’t use it if you live in a warm climate) but has twice the cores available (try to get the G0 stepping, it runs cooler). In general the E6600 should easily be enough for most musicians and producers.
CPU Cooler: The gigantuous Scythe Ninja. It’s about the size of Alaska and the weight of Roseanne, but it’s the single most effective CPU cooler. The stock Intel cooler is quite loud, so I would strongly advise against using it.
Motherboard: The Asus P5K. It’s passively cooled and Asus tends to be reliable. Whatever you do, do not get a motherboard with an actively cooled (with a fan) northbridge. These tiny fans are incredibly noisy as they spin at a very high rpm.
HDD: Hard drives are one of the most important noise sources in a computer. They tend to vibrate and cause low frequency noise on mics that are not properly isolated from vibrations. They also tend to cause loud noises when active. In the future we will be able to use solid state drives (which are noiseless), but until then a good recommendation is the Western Digital Caviar SE16 500GB. It has a lot of space and is the quietest hard drive out there. Whatever you do, do not install a 10.000 rpm hard drive if your computer is in the same room recordings will happen just so your computer will be a bit faster. Unless you enjoy a sound similar to rapid firing machine guns running through your recordings.
PSU: A critical component as they are a source of noise and determine how efficient power is used by your computer. Generally, if you purchase a Seasonic PSU you should be alright.
Case: Personally I am a big fan of the Antec Solo. It’s not too big and has this really neat hard drive suspension system which uses rubber bands to suspend the hard drive and isolate its vibrations (in combination with the WD SE16 this results in virtually noiseless operation). The Antec Sonata III isn’t bad either, but comes with a PSU which isn’t great. Don’t forget to set the case fan that comes with these cases to the lowest speed to ensure minimum noise.
Other components generally do not have much of an influence on the noise level of your computer. There are other means available to cool a computer silently, most notably water cooling and computer cases that function as a massive heat sink. Generally these are experimental, expensive or high maintenance and I would not recommend them to the average person.
If you still find your computer to be too noisy, you should consider placing your computer within a closet (if one is available nearby) and routing your cables through a small duct. It also helps to limit your use of omnidirectional microphones.
While your studio should now be properly isolated, recordings will probably sound quite horrible. This is due to the fact that your studio is not yet acoustically treated to ensure the best recording and/or production environment. In the next article I will discuss how to create a single room home studio which is both great for recording and production.
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Posted By Alex @ 12:00 AM
Author's site: http://www.isound.com
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winter_rose's comment posted March 3rd @ 8:45 PM:
Just a little addition to Alex's blog, afew years ago I had noise problems when building a commercial studio, unable to afford an Eastlake/Westlake conversion I rang local industrial noise consultants who specialised in industrial machine isolation in factorys.
This guy turned up and told me noise travels in two ways, airborne and structureborne, to eliminate structureborne sound he suggested a room within a room as Alex has, He also suggested a cheaper way which was just floating the floor on special absorbers, he produced one from his case to show me, After doing various calculations he told me I would need to float the foor on 12 of these and they were £60 each!!, (and this was 1986).
The moment I saw one of these "special" sound absorbers I recognised it straight away, I had fitted loads of them in the past when I was a car mechanic, they were car shockers, After telling this guy I would think on it I went of to the car spares place and bought the same thing but at £5 each (they were for a Mini), It took a bit of time placing them but in the end they worked great.
Another free tip I got regarding airborne sound was that an air space is just as good as a mass, before you plasterboard/fibreglass or whatever you are planning just screw a wooden frame to the wall giving a 2/3 inch air space.
Phil Planet.
Commentors site: http://www.magicwardrobe.co.uk |
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