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Review: ASUS QuieTrack CRW-5232AS & CD-S520/A4

ASUS QuieTrack CRW-5232AS & CD-S520 are examined for noise performance in SPCR’s second optical drive review. The new optical drives fare well against earlier ones regarded as quiet — or at least noise-reduced.

April 18, 2004 by Mike Chin

Asus CRW-5232AS
Asus CD-S520/A4
Manufacturer / Supplier Supplier
ASUS Computer

ASUS is one of the biggest component manufacturers in the PC industry. They made their name with motherboards, and have now expanded into almost every aspect of PC components, optical drives among them.

Recently, they submitted two new optical drives for scrutiny by SPCR. The CRW-5232AS and CD-S520/A4 are part of the exclusive ASUS QuieTrack Series, which are said to…

reduce noise without compromising performance thanks to ASUS AFFM and DDSS II technologies. AFFM (Airflow Field Modification) all but eliminates the uneven airflow inside ASUS drive resulting in quieter and more stable operation. The patented DDSSII (Double Dynamic Suspension System) stabilizes the optical pick-up head, achieving more precise tracking while reducing vibration and noise caused by high-revolution motors.

In addition, ASUS has introduced the world’s first online firmware update tool inside the included burning software. By using this intelligent tool, it will automatically remind you to update the drive firmware.

The ASUS QuieTrack page is an interesting read. Their comments on uneven airflow and pressure makes one think of Frisbees…

Noise and vibration are two major headaches users encounter when using a high-speed drive. AFFM is designed to change the uneven airflow field inside the drive because even pressure distribution leads to quieter and more stable operation.

ASUS CRW-5232AS and CD-S520/A4

The SPCR Approach to Optical Drives

As we wrote in the previous Samsung optical drives review, optical drives are among the PC components we have been reluctant to examine seriously for acoustic performance. It’s not that they don’t make noise; optical drives certainly do make a lot of noise. The question is whether any device can run quietly while spinning an intrinsically imbalanced 5″ diameter plastic disc at many thousands of RPM. The noise emitted by an optical drive is most closely related to the speed at which it is spinning the disc. Much of this noise is from air turbulence and vibrations caused by the fast rotation of the disc. Only some of it is mechanical drive and electronic motor noise.

But there are distinct differences in noise, even when the drives are rated for the same read / write speeds. They are all noisy, but some are noisier, and some are quieter.

It will be helpful to have an understanding of how optical drives work. Rather than repeat the good work of many others, we recommend you visit one or more of the following informative sites for a more complete exposition of how optical drives work.

PC Magazine‘s Flash animation of How Optical Drives Work

How CD Burners Work, a detailed look by howstuffworks.com

CD Player, also by howstuffworks.com

How DVDs and DVD Players Work, also by howstuffworks.com

Image courtesy of howstuffworks.com

Here, we are concerned primarily with the noise-producing parts of an optical drive, the parts that move:

  • A tracking mechanism moves the laser assembly so that the laser’s beam can follow the spiral track (from the innermost point outward). The tracking system has to be able to move the laser at micron resolutions and to position it quickly for random access. This is a typical source of noise.
  • A drive motor that spins the disc at precise speeds depending on which portion of the track is being read. This is the main source of noise.

Most optical drives of greater than ~12X read / write speed use constant angular velocity (CAV) or a compromise combination of CAV and constant linear velocity (CLV) to improve transfer rates at the inside edge of the disk. (See this explanation of CAV & CLV in The PC Guide web site.)


NOTE: The read / write performance of the optical drives we review will NOT be examined.

Our point of view is simple: Optical drive performance testing is already done by many other hardware sites. There is no need to duplicate such efforts. Any good performance testing takes time and effort. Time and resources at SPCR are precious and much better spent expanding our knowledge about the acoustic aspects of optical drives, which is hardly touched by any hardware reviewers. On top of all this, the performance difference between various makes is relatively subtle, and most modern optical drives are plenty fast for most applications; on the other hand, a very quiet optical drive is a gem and difficult to identify casually.

Web sites that provide good performance-oriented reviews of optical drives include:

The noises emitted by an optical drive can be divided into several categories. These are the categories of optical drive noise we will examine:

1) High speed data transfer / write rotational noise. This is usually the maximum level of noise produced by an optical drive. This noise will be measured in dBA @ 1 meter as well as described narratively. Each drive will also be run at a lower-noise reference read setting of 24X speed using CDBremse. This will allow an apples-to-apples comparison of optical drives that operate at different speeds.

DVD players will be measured for noise as well as listened to during normal playback of movies. The same set of CDs and DVDs will be used in doing read noise measurements and listening.

2) Positioning read noise. The noise made by an optical drive upon first insertion of the disc when the summary of the contents are scanned. This noise will be described.

3) Drawer mechanism noise. Some operate smoothly and quietly while others grind loudly. This noise will be described.

4) Rotational vibration. Some discs are less balanced and cause more wobbling and vibrations, which in turn, lead to more noise. The imbalance of discs is random and uncontrollable. However, some drives seem to deal better with imbalanced discs because of clamping / damping mechanisms. This vibration will be described.

A B&K model 2204 sound level meter is used for SPL (sound ressure level) measurements. This professional caliber SLM dates back to 1978, weighs over 10 pounds, and is completely analog in design. It has a dynamic range that spans over 140 dB. The unit’s absolute sensitivity reaches below 0 dBA. A quiet environment is a prerequisite to low noise testing; the lab has been measured down to 16~17 dBA at night.

We still rely more on subjective listening than on measurements. This is because measured dBA is only one aspect of noisiness, and human perception is the final arbiter.

Each optical drive is used on the test bench, not mounted in a PC case. This eliminate interactive variances that arise with vibrations, resonances, etc. in cases that only complicate acoustic analysis. Any one of several test systems will be used. They all run Windows XP and share the important characteristic of making very little noise, typically 20 dBA @ 1 meter, so that they do not impinge on the analysis of the noise made by optical drives under test.

Let’s move on to the ASUS drives.

ASUS CRW-5232AS Features

  • QuieTrack Series
    – DDSSII: Double Dynamic Suspension System
    – AFFM: Airflow Field Modification
  • Live Firmware Update Tool
  • Compact Drive
  • FlextraLink™ Buffer Underrun Errors Prevention Technology
  • FlextraSpeed™ Optimal Writing Speed Adjustment Technology
  • High-Speed DAE (Max. 52X) and VCD Data Extraction Supported
  • Vertical and Horizontal (+5° ~ -5°) Mounting Available
  • Unique Dust-Proof and Noise-Control Design

The ASUS CRW-5232AS comes with:

  • ASUS Internal IDE 52X CD-RW Drive x 1
  • Cable Set (IDE Cable*1pc + Screws*4pcs + Audio Cable*1pc) x 1
  • Manual (English + Traditional Chinese) x 1
  • Quick Installation Guide in 12 Languages x 1
  • Ejector Pin and Instruction Slip x 1
  • Nero Burning Software – Including Live Firmware Update Tool x 1
  • Cyberlink 3 in 1 (PowerDirector + ASUS DVD+ MediaShow) x 1

A very extensive set of technical specifications is provided.


Data Transfer Rate CAV write/ P-CAV rewrite/ CAV read
Sustained Transfer Rate CD (Read): 52X Max. 7800 KB/sec (CAV)
DAE: 52X Max. 7800 KB/sec (CAV)
CD-R (Write): 52X, 48X, 40X, 32X, 24X, 16X, 8X, 4X
CD-RW (Write): 32X, 24X, 16X, 12X, 10X, 8X, 4X
Random Access Time 100 ms typical @ 1/3 stroke
Writing Modes TAO (Track-At-Once), DAO (Disc-At-Once),SAO (Session-At-Once), Packet Write
O/S Compatibility Windows XP/ NT/ ME/ 2000/ 98SE
Interface ATAPI/ E-IDE
Supported Disc Formats DDisc Formats: CD-DA, CD-ROM, CD-ROM/XA, Photo CD, Mixed Mode CD-ROM, CD-I, CD-Extra, CD-Text, Video CD, DVCD, Bootable CD
Disc Diameters: 8 cm and 12 cm
Buffer Memory 2MB
Reliability MTBF
100,000 Power On Hours
Operating Duty Cycle (Read) 20% POH
Operating Duty Cycle (Write) 1% POH
1/2 hour
Configurations Mounting Orientation: Vertical and Horizontal (+5° ~ -5°)
Dimensions (H/W/D): 43 x 149.0 x 174.30 mm
Weight: 830g
Electrical Specifications Power Requirement: DC + 5V / DC +12 V
Tolerance: ± 5 % / ± 10 %
Environmental Specifications Temperature
Operating: 5°C to 45°C
Storage: -20°C to 60°C
Operating: 20% ~ 80% (Non-condensing)
Storage: 15% ~ 85% (Non-condensing)
Operating: 0.3 G peak (at 5~500 Hz)
Storage: 2.0 G peak (at 10~500 Hz)


Subjective Comments
52X CD read / write
Mostly air turbulence and a bit of motor whine
24X CD read / write
Smooth subdued air turbulence sound
CD play (Windows Media Player)
Quiet steady whirring
Positioning noise
Subdued damped clicking
Drawer mechanism
Very smooth, well damped


Like the previously reviewed Samsung optical drives, this ASUS CRW-5232AS works smoothly and quietly. The maximum noise level at 52X speed was actually 2-3 dBA quieter than with the Samsungs. There was a definite sense of all the mechanical sounds being well-damped somehow. Noise during CD playback or 24X speed operation are modest enough that most users will find it perfectly acceptable.

As for performance, casual use showed no anomalies of any kind, and every CD burn came out perfectly fine. It certainly feels like a fast optical drive. At 174mm, the drive is a bit shorter than most, which is a good thing, as it will help with cable management inside the case. The bundled NERO software is a very popular package, certainly my personal favorite among CD burn software.

The ASUS CRW-5232AS is recommended for noise-aware users.

NOTE: Apparently, an earlier version of this drive did not feature QuieTrack; just make sure you’re getting the new QuieTrack version before you buy.

Asus CD-S520/A4

Having reported all the above about the CRW-5232AS, there’s really not that much more to say about the CD-ROM version of the same optical drive. It sounds the same during read operations at the same speeds. If you need a quiet read-only CD drive, then the CD-S520/A4 is a good choice. I expect that in this day and age, most users have little interest in read-only optical drives, not when DVD and CD-RW drives cost only marginally more and provide so much more functionality.

We look forward to seeing the Asus QuieTrack technology in DVD drives, which are notable by their absence in the QuieTrack series at this point in time.

Much thanks to Asus Computer for the review samples.

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