Calming the Beast, Part II

A guide to making your studio quieter

By Paul Gilreath In Part I, we looked at several ways to bring computer noise into a manageable range. Now, we move forward with the second approach, which work in tandem with the first—moving the systems outside the listening environment. After your PC is quiet Once your PCs are as quiet as possible, you will need to judge whether you can live with the amount of noise they are producing. If so, position them in an appropriate place in your studio. If you are putting them directly on the floor or on your desk or table, consider putting neoprene under them to decrease vibration. Neoprene washes are available at most hardware stores. I use large 2” washers that are 1/4" thick (Fig 1). These decouple the computer from the workspace and greatly decrease vibrations. (As a side note, this technique also works great for decoupling speakers from a mixing desk.)

Fig 1. A 2” neoprene washer used to isolate vibrations If you have more than a couple of systems, you will probably need to isolate the computers from your listening environment. In addition, any other piece of gear with fans (such as the Waves APA32 and 44-M or an actively cooled gigabit switch) will contribute to the noise in the room and these products cannot be upgraded with quieter components. This means putting the computers and the offending gear in an isolated rack of some sort or in remote area such as a closet, machine room or even in another room. Remote Computing All things being equal, removing all of the systems from your listening environment will produce the best result. In fact, with this approach, ultra-quiet PCs are not even a necessity. Moving systems away from your listening area does have its pitfalls. You can’t get to them easily to load software, turn them on or off, reboot them manually, troubleshoot etc. But if you are a working composer,

chances are that you leave your systems on all the time and that manual reboots are infrequent. (If they are not, you probably have more problems in your studio than just computer noise.) Whether you are moving the systems outside of your studio, into an isolation box or into a closet inside the studio, you will be running a number of wires and cables to them. These include:

• VGA cable (one for a single head monitor card, two for a dual head card) • USB cable and PS2 cable for your keyboard and mouse • MIDI cable from your keyboard to your MIDI interface. Note that if the interface is in

your studio, then you will need to run another USB cable instead of the MIDI cable or you can use a USB hub for both.

• digital audio cable (fiber optic) if you need D/A conversion and your converter is in your studio

• or audio cables if your converter is internal on your computer or if your converter is with your computers.

If your monitors and keyboard will be within a 15-20 feet range from your computers, you can opt for a wireless keyboard and mouse configuration. Typically, a mouse charger is connected directly to the computer via a PS2 and USB cable. The charger serves as an antenna for the keyboard/mouse. This prevents you from having to run cables for your keyboard and mouse. In addition, you will probably find a KVM switch beneficial. A KVM switch connects one mouse, keyboard and monitor to multiple computers. The switch is positioned in the same area as your computers and connected to your monitor, mouse and keyboard through cabling. KVM switches come in different port configurations. One port equals one computer, so if you have five systems, you could consider want to buy a 5-port switch. I use an Iogear 8-port switch (Fig. 2) that was less Fig 2. An IoGear GCS138 KVM switch used by the author than $250 and it produces remarkable clarity. However, for Windows users, there is another option. Remote Desktop, a built-in feature in Windows XP Pro, allows you to access and control your systems remotely, provided they are all connected to a common network. This will then allow you to run only one set of cables (VGA, USB and PS2) to one of your systems (typically the DAW) and then use Remote Desktop (or any other commercially available remote software) to control the

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other systems from the hardwired system. I seldom need to use my KVM switch, but for performing duties on a system that must be viewed and controlled directly and not remotely (such as running the BIOS configuration), you must manipulate the computer from a keyboard directly connected to the system, so it does come in handy and prevents me from having to hook/unhook cables from the computers to the monitor and keyboard. But the majority of the time, I simply use Remote Desktop. The vast amount of time that I spend controlling my remote systems deals with loading sounds into my samplers, which can be done via Remote Desktop. You can change which system is being monitored directly from your keyboard, so you don’t have to get up and go to the front panel of the switch. VGA cables can be run up to about 50 feet or more using high quality cables. Longer runs mandate the use of VGA extender modules such as those made by Gefen, Minicom and Connectpro. Extender modules are placed at the monitor area and at the remote system. These modules are connected by CAT5 cables. Because CAT5 cable is so inexpensive and can be easily pulled through walls, it makes a great substitute for traditional dedicated cabling. Runs of up to 1300 feet are possible. USB cables can only be run about 16 feet without a “repeater” (which are found on the ends of repeater cables and amplifies the signal to allow longer length runs). With repeaters, USB runs of up to 80 feet can be used. For longer runs, you must use extenders, which use the same CAT5 format as VGA extenders. Another great product is the Minicom Smart KVM extender which uses CAT5 and provides connections for a monitor, keyboard and mouse (http://www.minicom.com/kvm_smartext.htm). Building a Machine Closet If remote locating your systems won’t work, you have two other options. The first is to build a computer closet within your studio to house the computers and the second is to use an isolation case. A closet can be built fairly easily over a weekend. In an existing studio or home, building a closet can be messy due to gypsum (drywall) dust, but it provides a relatively inexpensive solution for many people. The closet does not have to be exceedingly large. By using conventional soundproofing methods, you can achieve a virtually silent solution. These methods implement multiple layers of differing thicknesses of gypsum board without overlapping seams on the inside and outside of the closet, insulation and a solid core door with threshold and weather stripping. My last studio was built from scratch as an addition to my home. I had the privilege of working with architect, acoustician and studio designer, John Storyk of the Walters-Storyk Design Group. John put together all of the room’s acoustic treatment. The studio had a computer closet which allowed my control room to be virtually silent. I kept everything noisy in the closet and it worked like a charm. For those of you who would like to go this route, I want to present you with techniques published by The Gypsum Association (www.gypsum.org) as well as construction concepts provided to me by John. For those in the commercial music business, John needs no introduction. He has designed and provided acoustical planning for hundreds of studios. I know John from his work on my last studio where he provided all the acoustical planning and implementation oversight. I talked to John about computer noise issues. “In the past, musicians have had large machine rooms which housed their tape machines. As Pro Tools became the dominant format, the computer replaced large tape machines and these systems were typically positioned in the listening environment. The noise made by the computer was considered an acceptable trade-off for the format. But now, musicians and engineers want quiet control rooms again and the trend is to move the computers out of the room.”

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And according to Storyk, most of these are Pro Tools studios, which use only a single computer. Composers who use six or eight systems have even more reason to remove these systems from the listening area. “I really think that there is only one way to approach this problem and that is to remove the systems from the control room. I know some guys use isolation racks, but I’ve never recommended one in any of my designs. I don’t like them. I think that they are big and bulky devices that can add acoustical problems to the room due to the size”, Storyk said. “By using double layers of sheetrock, you can easily make a more functional environment to house your noisy computers.” Having worked with John on my last studio, I know his take on symmetry in the listening environment. Using his advice, I transitioned my old non-symmetrical room into an excellent writing and mixing environment so I am a believer. “It is so important to make sure that acoustics is part of the overall plan when you are isolating your computers. Otherwise, you’ll have spent money and removed noise from your room, but in its place you may totally changed the acoustics of the room. We do a lot of back of room corner closets, but when I plan for a closet on one side, I always mirror it on the other, even if they do not provide the same functionality,” says Storyk. In other words, if you put a sound proof closet on one side of your studio, you should consider making a mirror image of it on the other side, even if it is just the outer shell, so that you have symmetry on both sides. John was kind enough to provide us with some studio photos that show the position of the machine closets in a couple of his studios. The first picture is of Alicia Keys new studio (Fig. 3).

Fig 3. Alicia Key’s studio with machine closets in the rear

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Notice in the back left of the photo, you will see a door. That is an equipment closet that uses a glass door. John also designed film composer Carter Burwell’s personal studio (Fig 4). Again notice the equipment closet in the picture and in the blueprint (Fig 5), you can see how there are two closet areas in the rear of the studio.

Fig 4. Carter Burwell’s studio with machine closets

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Fig 5. Blueprints for Burwell’s studio. Notice placement of the machine closets So how do you go about putting in a closet? The first thing you must do is to decide where it will be positioned. Remember the symmetry issue and design you closet to be in an appropriate area. Also, you must consider ventilation and possibly conditioning the space. Once you’ve come up with a plan, the construction phase is not too complex as long as you follow some basic rules. If you

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already have a closet that will work, you have a real jump on the problem. Utilize the techniques below to augment the current closet if necessary. These are techniques that I used for my entire studio in my last home. Here are some concepts:

• Increased mass (additional layers of gypsum board) on the walls decreases sound transmission

• Two walls separated by an air space of only an inch or so have a lower sound transmission than a single wall, even when that wall has increased mass.

• When two walls are not possible, either stagger studs (using a 2x6 top and bottom plate instead of a 2x4) or use resilient channel. This will decouple the two sides of the wall.

• Seal all layers of gypsum board and do not overlap seams. This means that you have to use a different placement configuration when hanging the second layer. The exception here is when a wall has no seams. You can hang the next wall in the same configuration.

• Use sound absorption in the walls • Limit penetrations into the wall such as electrical boxes, plumbing, HVAC ducts. Seal all of

these penetrations with acoustical caulk. Seal the periphery. • Do not use any line of sight communications (such as an electrical outlet on each side of

the wall). If you can see into the closet, sound will come out. A Sound Transmission Class (STC) is a rating of how well a barrier (wall, ceiling, insulation, window, etc.) attenuates sound. This number is derived from sound attenuation values tested at sixteen standard frequencies from 125 Hz to 4000 Hz. The number is accurate for speech sounds but it is not as true for other sounds such as amplified music. In particular, sound made of frequencies below 125 Hz is much more difficult to attenuate than sounds made up of higher frequencies. The STC rating is an approximation of how many decibels (dB) the barrier will attenuate sound. The dB scale is logarithmic. Humans perceive a reduction of 10dB as being about half as loud as the original sound, so a noise that is originally 40dB that is attenuated 10dB will sound half as loud as the original. A product with a STC of 10 would accomplish this. So how much attenuation do you need? It depends on your computers. If you want to make sure you are constructing an adequate wall, but not overdoing it, you can use a noise meter, which will show you the approximate dB of your computers. These are available commercially from many sources, but Radio Shack sells a unit that is adequate for our use. I consider my systems to be very quiet. When mounted in a rack, each system demonstrates about 35 dB of noise from the front at a distance of about one foot and 38 dB from the back. At five feet, the noise drops to 32dB and 35dB. However, cumulatively, the noise from all seven systems at about two feet is 58dB from the front and 62dB from the rear. I also have a Waves APA32 which generates a fan noise of 32dB. At 15 feet, I measure about 38dB of noise. Human whispering averages about 20dB, while breathing is about 10dB. So if you want to get your computers to the “breathing level” and your systems measure about 55dB, you’ll need a wall with an STC of 45dB. A wall made of 2x4 studs with a layer of 1/2" gypsum board on each side has an STC of about 33, so you’ll have to do better than that. A wall with a 45 STC rating can be obtained using a conventional 2x4 stud wall and two layers of gypsum board on each side. If you use resilient channel on one side of the wall and use 5/8” gypsum board instead of 1/2", you only have to use one layer on each side and you will obtain a 50 rating. Resilient channel is a metal strip that is screwed into the wall studs and upon which the first layer of gypsum board is screwed. To reach a STC of 59, you’ll need to use resilient channel, and also

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two layers of gypsum board—two layers of 5/8” board on one side and a layer of 5/8” on the opposite with a finish layer using 1/4" board. If you tape and mud (but not finish) the inner layers, you will get a better STC rating. Because of the size, this will be an easy task to accomplish. You don’t have to make the inside seams look perfect. Just cover the seams with mud. Remember to make sure the seams from one layer don’t mimic the other. Stagger the seams if only by a few inches. Fill the walls with mineral fiber insulation. This is sometimes called acoustic board insulation. This is available from RockWool and others at commercial insulation companies as well as sound product companies like Auralex. Storyk also recommends using a vinyl barrier between one of the layer of sheetrock if your systems are particularly loud. This will provide another 4dB of reduction. Finally, he suggests using a Sonex type foam on the walls to provide absorption. Now for the final element—the weakest link in the chain—the door. Without having a special door made, your only choice is a solid wooden door, without any type of glass. These doors provide a good measure of sound attenuation, but not as good as your walls will be. The STC of a solid core door can range from 30 to 45, so make sure you are getting one that is at the high end of the scale. But most sound does not come though the door—it leaks around the door. Consequently, you will need to use a heavy gasket around the door and a threshold under the door. For many applications a solid core wooden exterior door and frame works well in these situations, since they are made to seal the door, unlike most interior doors. There are several companies that specialize in products that seal doors for soundproofing situations. Zero International (www.zerointernational.com) is a leader in this area. They provide several solutions for soundproofing doors. They are also a great source of information, with technical drawings that explain how to use soundproofing techniques in a studio environment. Another issue you need to plan for is wire runs. You will need to get cabling in and out of the closet. Storyk recommends using electrical conduit positioned in an “S” configuration. Keep the conduit as small as possible and fill each end with Sonex type foam. This will help minimize sound transmission Once you have committed to building a closet, you need to make sure you have adequate power and ventilation for your systems. Like in my Isobox, heat build up in a closet is a real issue, so you’ll need to make some accommodations to remove the hot air from the closet. Intel and AMD both state that running their components at their “nominal” temperature will greatly lengthen the life of the component. The best way to accomplish this is by providing a constantly cooled environment for your computers. In my first closet, I vented to the outside using a commercial bath fan mounted in the attic. It was far enough away from the closet that it did not introduce any noise. The fan pulled air out of the closet via a dryer duct. In order to allow fresh air in, I cut a whole in the wall and installed a small baffling box, which filtered noise to the control room as air was pulled in. The fan was on a thermostat which kicked into high gear if the temperature got too hot. It worked pretty well, but the temperature was always warm in the room but the CPUs always operated on the highest end of the operating temperature range. For my next closet, I plan to use a small ductless fixed air conditioner unit called the Mr. Slim M Series. It is made by Mitsubishi and it has received a lot of attention for music and computer room applications. They are small, extremely efficient and quiet (22dB for the 9000 and 12000 BTU

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units). Mr. Slim consists of an inside blower unit, an outside condenser unit and the connections between the two units (Fig 6). The blower unit can be installed on the ceiling or on a wall and it communicates with the outside compressor (which can be installed on the ground, side of a building or roof) via a single 3” piece conduit. Even though the unit uses positive heat exchange for cooling, it can still function optimally in outside environments down to 0ºF, so it is perfect for use in winter months, where you still need to cool the closet. These units can be found for about $1200 on eBay and installation will run about $250, so the entire system can be bought and installed for less than most computer systems. Storyk has used Mr. Slim in many studios, even in the control room or live studio (Fig 7).

Fig 6. The Mitsubishi Mr. Slim ductless air conditioning system

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Fig 7. A DVD suite with a Mr. Slim unit in the back left of the photo. Isolation Racks For those who must have their computers within the studio but cannot build a closet to house them, an isolation rack is the solution. Essentially an isolation rack is a traditional rack mounting within a case that provides a level of sound isolation. They often include a rack mounting system for your gear, a front and rear access and some acoustic treatment (foam) to further help with vibration and sound transmission. These are the most expensive solutions for noise isolation and because of the fact that they are mobile, they do not typically have the mass needed for total isolation. However, several companies provide excellent products that will produce an acceptable result including Custom Consoles of Nashville, TN (IsoBox), Middle Atlantic, XRackPro and others. 24U racks start at about $1500 and top out around $3000. It is essential when you order these products that you accurately measure the total wattage of your gear so that the manufacturer can implement the correct cooling system. You must purchase a system that will not only hold all of your computers, but that will also be able to cool the systems appropriately. When I moved last April, my studio became a 20x12 bonus room with small closets under the roofline. Since I needed to get up and running rather quickly, I decided to go with a 24U IsoBox (Fig. 8) made by Custom Consoles in Tennessee (www.custom-consoles.com). It includes four fans, a digital read out to display the inside and outside temps of the box and an alarm system, which goes off if the temperature gets too high or if any of the fans stop working. It provides about 25dB of noise reduction.

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One issue with isolation boxes is that they must be designed for the wattages of your systems. When I first purchased the box, I only had three systems and a few other rack mounted synths installed and the box worked like a charm—no heat buildup and great isolation. Now, I have seven systems (Fig 9 and 10) and through no fault of the box itself, it cannot remove the heat from the systems efficiently. So as a rule of thumb, always greatly over-estimate your needs. So it looks like I’ll be making a closet for myself very soon.

Fig 8. The IsoBox by Custom Consoles.

Fig 9. Author’s IsoBox front shows VisionDAW systems, a Big Ben and the IoGear KVM Switch

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Fig 10. Rear of IsoBox shows system wiring array. Neat wiring is a must to help with heat dissipation. Conclusion As our need for more power has brought multiple computers into our studios, the environment has grown noisier. By implementing the concepts and techniques presented here, you can regain your quiet surroundings and be aware of what is really important—your music. Links: Small air conditioner: www.mrslim.com Gypsum Association wall diagrams: http://www.gypsum.org/pdf/gypsum2.pdf John Storyk: www.wsdg.com Zero International: www.zerointernational.com Custom Consoles: www.custom-consoles.com Minicom Extender: www.minicom.com/kvm_smartext.htm

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