Antec MX-1: Actively Cooled External HDD Enclosure

Storage
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TESTING METHODOLOGY

The MX-1 was tested mostly for noise and cooling, using a Western Digital Caviar SE16 500GB drive sample tested last summer. The drive was measured in free air, and then again inside the enclosure to see how the enclosure affected noise, cooling or power. Hence, noise, temperature and power measurements depend on the drive installed. Test techniques from our Standard HDD Testing Methodology were used.


HDD mounted, ready to be closed up. Note: The base is flipped 180 degrees in this photo.

For testing, the eSATA option was chosen. This required removing the back plate on a spare PCI slot in the computer(s), and installing the SATA-to-eSATA adapter plate. The adapter has a captive SATA cable that connects to any spare SATA port on the motherboard. It then provides an eSATA port on the back of the computer. As noted in our review of the Icy Dock external HDD enclosure, the eSATA connectors engage much more securely than standard SATA.

The following tools were used during testing:

  • B&K model 1613 sound level meter
  • Seasonic Power Angel AC power meter
  • PC system 1: P4-2.66 system with fully passive cooling and a damped 2.5" notebook running Windows XP — silent for practical purposes
  • PC system 2: AMD A64-X2 4800+ system with two suspended 3.5" HDDs, measuring ~23 dBA@1m in a carpeted room
  • Hitachi HDD Feature Tool v2.04 — used to set AAM, check temperature
  • SpeedFan v4.28 to monitor temperature in Windows

Ambient conditions at the time of testing were 20 dBA and 21°C.

ACOUSTICS & VIBRATION

The MX-1 by itself

The first thing was to power up the MX-1 and have a listen to the fan. It was quiet, as promised. It measured around 20-21 dBA@1m, and sounded like a little hum from up close. There was little low or high frequency noise, and only a small amount of broadband wind noise. With the box closed, the noise softened and became essentially inaudible from a meter away. The airflow might be 10 cfm; it's not much, but enough to be easily felt at the vents.

In Idle Mode

The HDD sample is a quiet drive that originally measured 21 dBA@1m (placed on a soft piece of foam). A recheck of the SPL gave a slightly higher reading: 22 dBA@1m. Whether this is due to changes in ambient noise conditions, or wear and tear on the drive itself is difficult to say.

Subjectively, the drive is much noisier than the fan of the MX-1. The HDD has a much greater low frequency noise, which is de-emphasized by the A-weighting applied to our dB measurements. That noise has its fundamental frequency at 120Hz, low enough to cause vibration-induced noise in most any object that comes in contact with the drive. (A 7200 rpm drive spins 120 times per second; ie, 120Hz.)

With the WD was installed in the MX-1 and powered up, the noise of the drive completely masked the noise of the internal fan. Placed atop a sturdy desk, there was a bit of vibration-borne hum, which was expected. The silicone gasket definitely helps, but it cannot eliminate all the vibration from getting conducted into the structure of the MX-1, and through it, into the desk. The power and data connections also provide a hard path for the HDD vibrations to be conducted through the PCB into the MX-1. Some of the increase in noise comes from cavitation effects: The drive "excites" the air resonances of the cavity (the interior space of the MX-1) and causes the noise to be a bit accentuated. This is simply unavoidable.

The noise of the drive in the MX-1 directly atop the desk measured 23 dBA@1m. Most of the increase was due to the mechanical vibration coupling and resonance effects. The hum reduced considerably when the unit was lifted and held off the desk, but the measured SPL did not change. Mounted vertically, the drive in the MX-1 displayed slightly less vibration than just by itself.

The overall contribution of the MX-1 to the noise of the hard drive was very small. Without paying close attention, the difference in noise between the bare drive and the MX-1 enclosed drive would be difficult for many people to notice.

In Seek Mode

The MX-1 with the WD drive was hooked up to the computer on the fly, while both were running. Device Manager in Windows XP Pro was used to recognize the external drive without any issues. Seek / write mode was engaged by copying all the files from My Documents in the main HDD to the MX-1. The automatic acoustic management (AAM) on the WD had been already been set to minimum noise using the Hitachi Feature Tool Version 2.04. The seek noise was muted, but slightly more hollow or resonant sounding than when the drive was sitting bare on the desk. Peaks reached perhaps 25 dBA@1m. It sounded a bit like popcorn popping softly in the distance.

With AAM disengaged, the seek/write noise was considerably louder. It was about as loud with the bare drive as well, but sharper and harder; in the MX-1 it sounded a bit more resonant.

COOLING

In idle mode, the HDD temperature in the MX-1 never exceeded 31°C. After an hour of continuous file transfers and defragging, the temperature rose to 34°C. Just 5~10 minutes after the drive was allowed to rest at idle, the temperature dropped back down to 30°C.

This is impressive performance. Even positioned just behind a 92mm fan spinning constantly at 5V at an open front vent, the data drive on the second PC system idles around 40°C — although this is not directly comparable because it is a different drive from a different brand.

There's no question that the MX-1 provides excellent HDD cooling. Simply placing the WD drive on the floor next to the open PC, powered by the power supply in the PC and connected directly via a long SATA cable, gave these results: 42°C in idle, 44°C after extended load. The improvement in cooling effected by the MX-1 was at least 10°C. Additionally, with the bare drive, the temperature took a long time (over 30 minutes) to drop back down after the period of extended load.

POWER

The electronics and AC/DC adapter of the MX-1 took very little extra power. The resolution of the power meter was a bit too coarse to show it precisely, but the additional power can be estimated to be approximately 2.5W. Most of this power is probably lost as heat during the conversion from AC to DC in the adapter. The PCB in the MX-1 adds almost no heat to that of the hard drive.

TEST SUMMARY: Antec MX-1
Feature
Bare Drive
Drive in MX-1
Difference
Vibration (Horizontal)
4
4
0
Vibration (Vertical)
4
5
+1
Noise: Idle
22 dBA@1m
23 dBA@1m
+1 dBA@1m
Noise: Seek (AAM)
23 dBA@1m
24 dBA@1m
+1 dBA@1m
Noise: Seek (Normal)
26 dBA@1m
27 dBA@1m
+1 dBA@1m
Power: Idle
9W
11~12W
+2~3W
Power: Seek (AAM)
9W
11~12W
+2~3W
Power: Seek (Normal)
11W
13~14W
+2~3W
HDD Temperature
42°~44°C
29°~34°C
over -10°C

 

CONCLUSIONS

The Antec MX-1 is an unusual and welcome external hard drive enclosure. Its combination of features is completely unique: eSATA and USB 2.0 support, along with highly effective active cooling and virtually no increase in noise. The last two qualities make the MX-1 stand head and shoulders above any other external drive enclosure device we know of today. There's really nothing else quite like it.

eSATA makes it possible to isolate the boot drive externally, and the MX-1 enclosure could make the drive quieter than when it is installed inside the system. The supplied ~40" long eSATA cable is not quite long enough for us to put the MX-1 in an acoustically padded drawer (with a bit of ventilation) that could eliminate all hard drive noise from your PC. Experimentation is in order.

And although defragmentation and other extended sessions of seek/write modes did show up some mild accentuation of seek noise, in normal use, the acoustics of the MX-1 are determined mostly by acoustics of the drive. Choose a quiet drive, and it will be quiet. But it is unrealistic to put in a noisy beast and expect the MX-1 to subdue it.

The range of options and applications for the MX-1 are varied, like other external storage enclosures. The difference here is that unlike most of them, you need not worry about cooling for your drive and its precious data, and the additional noise will not make you want to turn the thing off ASAP — as long as you choose a decently quiet drive.

If SPCR awarded stars, the Antec MX-1 would get five. It's a great little device. Kudos for Antec's design team for coming up with a landmark product.

UPDATE - June 29, 2008

Occasional comments about the fan in the MX-1 being noisier than described here surfaced in the discussion thread very soon after this article was posted. They were a minority, however, as many reported the similar quiet acoustics we found. Over time, however, the complaints about the MX-1's fan noise have grown. We caution prospective buyers that the production fan might have changed (without any official version change), in which case, our acoustic assessment might no longer be valid.

 



Many thanks to Antec for the opportunity to review the MX-1.

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SPCR Articles of Related Interest:
SPCR's Hard Drive Testing Methodology
SPCR's Recommended Hard Drives
Icy Dock eSATA external HDD enclosure
Western Digital Caviar SE16 500 GB

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