One of the ultimate goals of a Home Theater PC enthusiast is to achieve a completely silent appliance. There are several ways to achieve this by using low-power motherboards, solid-state drives, and cards that only require passive cooling. Although the components you choose in your system plays a significant part of its silence, the next level of noise reduction is reached when you apply sound dampening material inside your computer.
It makes logical sense, as car enthusiasts have been doing this for years to decrease vibration and road noise for mobile audio systems. You would think that any old foam will do, but if you take a look around you’ll see that acoustic material has some serious science behind it. Different materials target different frequencies, and a PC’s moving parts generate much higher pitches than a car.
The AcoustiPack Extra foam blocks
A lot of testing and research has been done by many companies to come up with acoustic material to silence your PC or home theater rig. One of the high-end materials comes from Acousti Products, who asked us to test their AcoustiPack Ultimate material, along with their AcoustiPack Extra foam. If you really want to read all of the technical stuff, you can check that out on the last page of this review.
AcoustiPack ULTIMATE sets a new standard for PC soundproofing material kits, where the maximum noise reduction is required in a limited space. This multi-layer materials kit includes 3 sheets; two 2-layer (4mm thick) and one sheet of our latest generation 3-layer materials, providing superb levels of noise reduction despite the thickness being only 7mm. This soundproofing kit is designed to reduce the noise emanating from noisy PCs with case sizes ranging from standard ATX up to larger E-ATX and pedestal server cases used by gamers, power-users and small business usersThe new AcoustiPack™ EXTRA Foam Blocks pack contains 3 acoustic foam blocks. These can be used inside any vacant drive bays to help increase the absorption of unwanted sound energy. Once installed, the foam blocks also help to reduce the internal air volume inside your PC or server case, which in turn may improve airflow velocity and the cooling performance.
The blocks are made from profession-grade dense acoustic foam, which is certified to UL94-HF1 fire rating. The foam is especially effective at absorbing sound at higher-frequency, such as HDD whine, or high-pitch noise from motherboard components. The foam is black, and flexible enough to squeeze into empty 5¼ inch or 3½ inch drive bays to pressure-fit.
Next we take a look at what makes this stuff so special…
The AcoustiPack Ultimate comes with three black sheets consisting of three layers. The top layer is a thin piece of black foam (the acoustic foam), which is then attached to a thin rubber sheet (the acoustic barrier). A strong adhesive is on the back, making up the third layer. The foam has lots of little sparkly bits throughout, which will certainly reflect all of your case lights like a Christmas tree ornament. On the back of each 18×17″ sheet is an adhesive backing that can be used a few times.
The AcoustiPack Extra is a collection of three medium-density foam blocks that are pre-cut to fit inside a computer’s drive bays. You get two 5.25″ bay blocks and one 3.5″ bay block. These pieces fit so snugly that no adhesive is required, but Acousti recommends that you not place these directly next to anything that generates heat, such as a hard drive.
Is your case a good candidate?
You must consider the type of case that is to be silenced when using these acoustic materials. Some cases just won’t benefit very much from them, mainly cases with windows and cases with a lot of natural ventillation. The Lian Li V-1000 case is very open and airy, and wouldn’t benefit as much as a “closed” case. This foam adds an extra level of professionalism to any rig, so you may want to put this in a windowed case just for the “oooh” factor, and it covers scratches on aluminum very nicely.
A closed case with tight joints (like the ThermalTake DH102 reviewed here or the GlacialTech Altair A381 here) are good candidates. A slimline case like the GMC AVC-S7 (reviewed here) may not work because there is already a tight squeeze for space.
ThermalTake DH102 and GlacialTech Altair A381
The sheets are about the same height as a mid-tower case, so there is just about enough to cover both the left and right side, top and bottom of a modest case. One sheet will be used for each side, and half-sheet for both the top and bottom, and you might have a few scraps left over for some of the back. Cases look really boss when the drive cages are also covered, but this really isn’t practical given all the holes needed to secure the drives. The material should also not touch the power supply or anything that generates heat or conducts electricity, so don’t go crazy and install it under the motherboard.
Installing the Extra foam is only as difficult as your case is complicated. My Lian Li V-1000 case for example does not allow easy access to external drive bays, so inserting foam blocks through the inside is rather annoying with equipment installed.
Installing the Ultimate material is a bit more involved, because you have to cut it to shape. It is highly recommended that you remove all components and ensure your case is completely dust-free. Measure each side that needs material and then cut the sheets to size. For a professional look you really want straight cuts, so I would use a ruler and heavy-duty hobby knife rather than scissors. Since this stuff isn’t cheap then you need to treat it with respect and it will respect you back.
The paper backing comes right off to reveal the adhesive
You will probably run into areas that need special attention, like getting around drive cages, screws, or holes. If you cut a slit for bolts and screws then they will easily poke through. If you have a drive cage that runs the entire height of your case then you’ll have to make adjustments to fit around this.
Get a feel for the placement by starting in one corner and roll it out until you reach the other corner. Peel off the backing and place into position, and once you’ve done this you can poke any screws through the foam. The adhesive has a little give in case you get the placement wrong, but will lose its stickiness after a few times of doing this. I find that rolling the material (starting from one side) is better than just placing it down flat.
The material really catches the light!
You can also get rather creative with this foam. Instead of hideous wires snaking through your system, you can cut out a cavity and tuck them inside the foam blocks
Sure the stuff makes the inside of your case look like a luxury car, but you bought high-end acoustic material to reduct noise. Once everything is installed then you definately notice a difference. Using a sound pressure meter I found that the installation of acoustic material reduced noise from 57 dBA to about 45 dBA, and the sound of hard drives was virtually eliminated.
Calculations showing the affect on STL of multi-layer materials adhered to a steel panel. 12mm & 13mm materials adhered to a steel plate are shown to cause a significant increase in STL above 500Hz, and 6.9mm materials similarly above 1kHz.
One thing to consider is how dust will react with this pourous foamy material. Sure, it looks great now, but dust will certainly get into the little nooks and crannies, which may require a vacuum to clean out.
You may not have noticed how much a hollow PC case echoes, but the contrast of a properly-silenced case is obvious. It won’t make a noisy case absolutely silent, but does eliminate hard drive clicks and high-pitched whines. To truly silence your PC further, you need low-RPM fans and passive heatsinks wherever possible.
Measurements of acoustic absorption show an improved low-frequency performance (below 1kHz) in multi-layer materials. These observations may be the result of mass-spring resonance occurring in the decoupled barrier layer within the materials.
Not only does the AcoustiPack Ultimate material and Extra foam significantly reduce excess PC noise, but it makes it look much more attractive and professional. It’s that last bit of polish on a serious home theater or gaming rig.
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1. Retail Kits – ULTIMATE, Lite & EXTRA: Sheet
The above retail kits contain the following materials:
2-Layer Acoustic Composite Materials:
3.8mm Code: SA1B3.2F [UL94-V0]
3-Layer Acoustic Composite Materials (Patent Pending*):
6.9mm Code: SA3.2F1B3.2F [UL94-V0]
For full details see section 3 below.
2. AcoustiML™ for OEMs
AcoustiML™ Soundproofing Materials are supplied to manufacturers for OEM Applications either in sheet form or pre cut kits:
2-Layer Acoustic Composite Materials:
3.8mm Code: SA1B3.2F [UL94-V0]
3-Layer Acoustic Composite Materials (Patent Pending*):
6.9mm Code: SA3.2F1B3.2F [UL94-V0]
12.0mm Code: SA6.4F2B6.4F [UL94-V2]
13.0mm Code: SA4.8F3B6.4F [UL94-V1]
For full details see section 3 below.
* Details of all Patents & Patents Pending are available upon request. Acousti Products Ltd asserts Intellectual Ownership of all these products.
3. Technical Overview
General Product Description:
A range of very low-flammability composite soundproofing materials suitable for various noise control applications inside electronic/electrical enclosures.
The product is flexible, dark grey/black, and is comprised of either two or more discreet layers. Thicknesses up to 4mm are dual-layer, and between 4mm up to 13mm are triple-layered. The product is supplied as cut parts or as raw sheets, with self-adhesive on one side suitable for adhesion to a wide range of substrate types (sheet steel, powder coated/painted metal, glass, laminate, MDF and plastics etc.).
The product offers superior acoustic performance (high sound transmission loss and good absorption at lower frequencies) when compared to typical dual or homogenous thin-layer soundproofing materials (see Acoustic Performance).
The materials are not dust generating, and do not chip or crumble upon light abrasion. Unlike other composites, AcoustiML™ materials are manufactured without the use of laminating adhesives. Layers of acoustic foam and acoustic barrier are physically bonded together during manufacture. The resulting bond ensures against delamination.
The individual components of the composite are certified and UL listed for low flammabilty. The finished composites have also been tested to UL94 (vertical burning test), and meet class V0-V2 (variable with thickness – see Flammability). This satisfies BS EN 60950-1:2002 ‘Information Technology Equipment – Safety’ section 4.7 with respect to resistance to fire for materials inside fire enclosures.
Material Property Data:
| Physical Properties | |||||
| Product Code: |
Tolerances
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SA1B3.2F
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SA3.2F1B3.2F
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SA6.4F2B6.4F
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SA4.8F3B6.4F
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| Number of Layers: |
2 Layer
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3 Layer
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| Nominal Thickness (mm): |
±10%
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3.8mm
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6.9mm
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12.0mm
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13.0mm
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| Colour: |
Dark Grey / Black
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| Nominal Weight (Kg/m2) [Lb/ft2]: |
±10%
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2.07 [0.42]
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2.28 [0.47]
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4.54 [0.93]
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6.32 [1.29]
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| Max. Sheet Width** (m) [inches]: |
1.3 [54]
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**Maximum Sheet Width is the maximum usable width of a raw sheet of material. There is no limit on the max. usable sheet length (except that practicably limited by handling & shipping).
| Flammability (Composite) | ||||
| Product Code: |
SA1B3.2F
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SA3.2F1B3.2F
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SA6.4F2B6.4F
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SA4.8F3B6.4F
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| UL94 Classification†: |
PASS – V0
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PASS – V0
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PASS – V2
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PASS – V1
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†UL94 is the ‘Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances’
| Environmental Properties | ||||
| Product Code: |
SA1B3.2F
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SA3.2F1B3.2F
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SA6.4F2B6.4F
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SA4.8F3B6.4F
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| Normal Operating Temperatures: |
0°C (32°F) to 93°C (200°F)
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RoHS Statement: None of the materials listed in the RoHS Directive (EU Directive 2002/95/EC) have been used in the formulation of these products.
Figure 1: Calculations showing the affect on STL of multi-layer materials adhered to a steel panel. 12mm & 13mm materials adhered to a steel plate are shown to cause a significant increase in STL above 500Hz, and 6.9mm materials similarly above 1kHz.
Figure 2: Measurements of acoustic absorption show an improved low-frequency performance (below 1kHz) in multi-layer materials. These observations may be the result of mass-spring resonance occurring in the decoupled barrier layer within the materials.
Acoustic Performance:
Sound energy from electronic equipment is typically broadband, and ranges from 100Hz to 10kHz.
In order to effectively treat unwanted noise inside electronic enclosures using soundproofing materials, the materials need both to enhance the sound transmission loss of the enclosure itself, and offer effective absorption of airborne sound reverberating inside the enclosure prior to escape.
Acousti ML™ composites effectively both impede and attenuate high and low frequencies, as a result of the unique multi-layered construction of the materials. The transmission loss of sound energy is enhanced by the dense acoustic barrier layer, and mid- and higher-range frequencies (above 1KHz) are effectively attenuated by acoustic foam layers.
Vibration Damping
In addition, the materials also assist vibration damping of the enclosure side walls and structure, which further helps to reduce reradiated noise.
Decoupled Acoustic Barrier Layer
The dense acoustic barrier layer in 3-layer materials is ‘suspended’ within a foam layer, forming a multi-layer system. This construction is more acoustically effective than using a barrier mass layer directly against the substrate (without a spacer), and results in higher sound transmission loss (STL) – see Figure 1. The double-wall system is analogous to that of double-glazing.
In addition, the decoupled mass layer also enhances low frequency absorption performance. Figure 2 shows the results from a random incidence reverberation room test normalised to ASTM C423 1999 on two materials (both 3-layer). The same effects have also be observed in smaller-scale Impedance Tube absorption tests (such as ASTM C 384-98).