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The Silent Box was tested against the only other drive enclosure officially reviewed by SPCR: The Smart
Drive. Each enclosure was tested for effectiveness in reducing airborne
acoustics and vibration, and also for how well it dissipates heat. Two reference
drives were used: The noisiest drive we could find, and the highest
vibration drive. Each drive was tested in free air according to our
standard hard drive testing methodology, and then again in each of the enclosures.
Hard drive temperatures were measured using S.M.A.R.T. reporting via SpeedFan
4.23. The drive was placed in open air on a carpeted surface and allowed
to idle until the temperature stabilized. Typically, it took about an hour and
a half for the temperature to stabilize. Because there was no airflow across
the drives and only a small potential for heat conduction through the carpeted
surface, our test bench conditions may be slightly tougher than an actual case.
However, the ambient temperature during testing was lower than most system temperatures,
so there is also a thermal benefit to our test bench. Our thermal testing is
designed to reveal differences between the different enclosures, and may not
represent the exact thermal performance inside a case.
Ambient conditions during testing were 24°C and 18 dBA/1m.
SMART DRIVE AND SILENT BOX NOISE REDUCTION CHARACTERISTICS
Reference Drive State
(10 = no vibration)
Enclosed in Smart Drive
Enclosed in Silent Box
The reference drive that we used to evaluate the reduction in airborne acoustics
was the noisiest drive we could find in the lab. Its identity will not be revealed
to protect the innocent. Suffice to say that it has seen over three years of
daily use, and is no longer being manufactured.
Its noise character is best described as a grating metallic whine that cycles
by about 2 dBA/1m in volume. All measurements of the drive were made at the
peak of the cycle. The drive also makes a highly resonant ringing sound that
fades in and out in sync with the cycle of the whine. Seek noise is almost inaudible,
but this is because the idle noise is so loud, not because the seeks are quiet.
Smart Drive, by Grow Up Japan
The Smart Drive is a nicely designed aluminum HDD quieting box.
SPCR's review back in June 2002 admired its precision fit and finish, and the floating aluminum box in box design. The inside box kind of "floats" acoustically in thermally conductive damping foam. (Please read the whole Smart Drive review for full details.)
The Silent Box's DIY Predecessor
They say there's nothing new under the sun. There's also hardly anything new in the quiet PC market that SPCR enthusiasts haven't done already. The Silent Box is a refined echo of a HDD silencing box made from rubber and described in the SPCR article Rubber Boxes & Carved Foam: More HDD Silencing. It was made not from Nitrile Butadiene Rubber but block print carving rubber (for art hobbyists), and there was no heatpipe heatsink nor inner layer of Styrene
Butadiene Rubber, but Leo Quan's rubber box did work, and it preceded Scythe's commercial effort by over two years.
Who can deny the possibility that Leo's Rubber Box could have been the inspiration for Scythe's Silent Box? After all, it's not just consumers who browse SPCR regularly but also many savvy and interested individuals in the industry. (Take a bow, Leo.)
The Smart Drive is most effective for cutting out the biting high frequencies
from the test drive. What's left is a mid-band hum that's about 6 dBA/1m quieter
than the drive in free air. However, it does nothing for the resonant ringing
that now dominates the character of the noise. The drop in volume is substantial;
airborne noise could probably be dropped below ambient with a quieter drive,
although our test drive is merely reduced from "noisy" to "somewhat
quiet". Even enclosed, our reference noisy drive could not get down to the level of
quiet exhibited by modern drives in free air.
Perhaps because of the reduction in idle noise, seeks are more clearly audible
inside the Smart Drive. They sound less sharp than in free air, and cause a
low rumble that was not previously audible. Overall, the quality of seek noise
is an improvement even if they are slightly more audible over the idle noise.
The effect of the Smart Drive on vibration is small, in the realm of 1-2 points
on our scale of vibration. Unless a very low vibration drive is used to begin
with, there is still room for improvement. Only the lowest vibration 3.5"
drives will gain enough damping from the Smart Drive not to benefit further
from suspension mounting.
The Smart Drive is made of aluminum and is designed with heat concerns in mind.
Our test drive saw a modest 2°C drop in the idle temperature when mounted
in the Smart Box. This is not a large improvement, but it does suggest that
it's not going to cook the drive when mounted inside a case. Our thermal reference
requires a small amount of airflow to be safely run in a real system, and this
is still true when mounted inside the Smart Drive.
Silent Box, by Scythe
The acoustic improvement offered by the Silent Box is not as dramatic as for
the Smart Drive. Neither the character nor the volume of our reference drive
improved as much as they did for the Smart Drive. As with the Smart Drive, the
primary character of the noise is a resonant ringing. However, in addition to
this, some of the sharp motor whine still remained, modulated by an odd "throbbing"
quality that may have been hidden under the whine of the motor before it was
installed in the Silent Box. The noise reduction is probably enough to
silence a quieter drive, but some care in drive selection will need to be taken,
as the improvement is not large.
The effect on seek noise was similar to that of the Smart Drive: Seeks became
slightly more audible, but they sounded like a low rumble rather than a sharp
clatter. The rumble may be slightly louder than for the Smart Drive, but it
is still close enough to the idle level that it is not intrusive.
For vibration, the softer rubber lining seems to help. It was very difficult
to judge the magnitude of the improvement, but it seems significant.
The rubber exterior and high weight of the Silent Box made our vibration test
box unreliable, as it had the effect of damping
the box as well as the drive! Based on some tactile observations (holding it in our hands) as well as
an examination of the Silent Box inside a case, we cautiously place the improvement
at around four points. We are unsure of how effective the Silent Box is for
damping lower levels of vibration, but it can probably be mounted in an a optical drive bay with a low vibration 3.5" drive without incurring much cost in vibration-induced noise. Results will depend on your case and what it sits on something resilient like carpet is better than a hard wood floor, for example.
The Heatlane cooling provided by the Silent Box appeared to wok well, but this improvement may
be artificial because the Heatlane transfers heat from the bottom of
the drive where we suspect the thermal diode is located. As mentioned, the surface
area of the aluminum frame is not large (it's about half the size of the Smart
Drive), so we are unsure of where the Heatlane is transferring the heat to.
Nevertheless, our drive recorded a 4°C drop in temperature inside the Silent
Box. How this translates to thermal performance when installed in a system will depend greatly on system specifics. There will be some conduction of heat through the rubber surface when installed in a 5 1/4" drive bay, but how much this will offset the lack of airflow around the optical bays in a typical case can only be judged in operation in the specific system.
Audio recordings were made with the reference noisy drive installed
in each enclosure and in free air. They are presented here in MP3 format. The
recording for the reference drive was made according to our
standard drive testing methodology, and contains 10 seconds of idle noise
followed by 10 seconds each of seek noise with AAM enabled and disabled. Because
our reference drive does not appear to support AAM, this second section of seek
noise was dropped when we recorded the drive inside the enclosures.
Noisy Drive in Free Air (Idle: 31 dBA/1m / Seek: 32 dBA/1m)
Noisy Drive inside Smart Drive (Idle: 25 dBA/1m / Seek: 26 dBA/1m)
Noisy Drive inside Silent Box (Idle: 27 dBA/1m / Seek: 28 dBA/1m)
Barracuda IV ST340016A (Idle: 21 / AAM: 23 / Seek: 25-26 dBA/1m)
Spinpoint P80 SP0802N, Nidec Motor (Idle: 21 / AAM: 23-24 / Seek: 25-26 dBA/1m)
Spinpoint P80 SP0802N, JVC Motor (Idle: 21 / AAM: 25 / Seek: 27 dBA/1m)
case fan @ 5V (17 dBA/1m) Reference
HOW TO LISTEN & COMPARE
These recordings were made
with a high resolution studio quality digital recording system. The hard
drive was placed on soft foam to isolate the airborne noise that it produces;
recordings do not take into account the vibration noise that hard
drives produce. The microphone was centered 3" above the top face
of the drive enclosure. The ambient noise during most recordings is 18
dBA or lower.
To set the volume to a realistic level (similar to the
original), try playing the Nexus 92 fan reference recording and
setting the volume so that it is barely audible. Then don't reset the
volume and play the other sound files. Of course, tone controls or other
effects should all be turned off or set to neutral. The accuracy of the reproduced sound will be profoundly affected by the fidelity of your audio playback system. For full details on
how to calibrate your sound system to get the most valid listening comparison,
please see the yellow text box entitled Listen to the Fans
on page four of the article
SPCR's Test / Sound Lab: A Short Tour.
The Silent Box is a good product for those who have a quiet drive but are seeking
silence, not mere quiet. Those with noisy drives are likely to see a
bigger improvement from upgrading their drive, while most quiet drives will fall
below the noise of even "quiet" fans. The Silent Box is not the first
product you should buy when putting together a quiet system, but it may be one
of the last. In a system where even a quiet drive is
still a major source of noise, the Silent Box may provide that final bit of
noise reduction. Then again, silencers are an obsessive bunch we
like to tinker with our systems even when we can't hear them!
The Silent Box may also find a niche among those who have a preference for
large capacity drives, which are noisier than lower capacity models. The Silent Box
can bring the noise of these drives down to the level of their smaller, quieter
Carefully paired with a low vibration drive, the Silent Box may be useful as
an alternative to drive suspension. Such a drive would need to be reasonably
quiet already, as the reduction in airborne noise is not enough to silence a
loud drive. So long as some care is taken to choose the right drive, the
Silent Box is capable of performing as advertised: A "silent box"
may indeed be a possibility.
In direct comparison with the Smart Drive (and its later variants -- the 2002 model and the copper version), it's not quite as effective on acoustic silencing but better at vibration damping. It offers a somewhat different balance of strengths.
Installation is a bit involved, and the fit isn't perfect, but these flaws
are forgivable if you only need to install one drive one time. On the other hand, our
testing required countless installations, and we got a bit sick of the excessive
care that is required not to strip the screw holes.
Like aftermarket heatsinks, fanless power supplies and high-end cases, the
Silent Box is an enthusiast product: It is designed for the very specific purpose
of damping hard drive noise. It provides a small benefit that cannot be achieved
in any other way, except perhaps by copying Leo Quan's groundbreaking DIY rubber box from a couple years ago. Used properly, the Silent Box makes an excellent addition
to a quiet case, but it is not the place to begin when silencing a computer.
Many thanks to Scythe
USA for this Silent Box sample.
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