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Testing & Results
In order to measure the technical performance of the Sirus several basic tests were performed. The high and low frequency limits were determined by playing a sweeping tone and determining the exact cutoff frequencies. Then the dynamic range is determined by putting the volume at full and playing wav files with incrementally lowered dB output. Independence of the 5.1 surround sound channels is tested using an AC3 audio source meant for that purpose. Many DVDs contain tools for these types of tests. Finally, the tonal qualities are are evaluated throughout these tests to determine the general quality and quality of the speaker crossovers.
As a more subjective test the Sirus was used to listen to stereo and surround sound movies, games, and music (yes, there are artists who compose in 5.1). These tests are more about the user experience and perceived quality of the headset over a wide range of applications. Multiple test systems were used to find any quality differences that might be due to variables outside of the Sirus.
Tests were repeated on all test systems using both the USB and TSR cables.
Test System 1
Test System 2
- Motherboard: Foxconn G33M02
- System Memory: 2 x 1GB DDR2-667
- Processor: Intel Core 2 Duo E7200 @ 2.53 GHz
- Video: ATI Radeon X850XT
- Disk Drive: Western Digital WD400BD-75JMAQ
- Operating System: Windows XP Professional
- Call of Duty 4: Modern Warfare 2
- Enemy Territory: Quake Wars
- Battlefield: Bad Company 2
- Just Cause 2
- Internet Explorer
- Windows Media Player
- VLC Media Player
High Frequency Limit: I first used a wav file that sweeps from 22 kHz downward. With the volume maxed I could hear some very slight aliasing down to 18 kHz. At 18 kHz the aliasing stopped and I could hear the first clean tone. I'm confident I would have heard higher pitches since I can hear frequencies used to repel pests and mosquitoes. Next I played a wav file that sweeps from 10 Hz upward. I could not hear anything until 20 Hz where the first tone is heard and the headset barely vibrates. This gives the Sirus a frequency range from 20-18000 Hz.
Low Frequency Limit: A series of wav files that get progressively quieter were used to determine the low frequency limit. In my office I could distinguish words down to 66 dB below full volume. While my frequency detection is quite good, I'm not good at distinguishing quietly spoken words. So in a quieter environment and for someone with better hearing the Sirus' dynamic range is at least below 66 dB.
Surround Sound Channel Quality: Several 5.1 surround sound system tests to determine the quality of the surround sound channels. One example is the THX Optimizer included on many DVD's. From these tests I found that I could not totally disable the sound from a single channel. Despite muting all but one channel I can still hear the audio from the other channels, though the audio was softer. This was true for both the USB interface through the Tactical Mixing Console and the 5.1 TSR cable. Despite this setback, the channels gave a predictable response to the 5.1 tests.
Tonal Quality: There was one major difference between using the USB versus the TSR interface. The USB interface gave me interference from the mouse, from the hard drive, from the video card, from everything. It was a low thudding or clicking sound. I really like using the Tactical Mixing Console so I was determined to find the root cause. I tried all different combinations of USB ports but kept getting some level of the problem. I switched to my front USB ports and it improved but did not disappear. This only happened on my GigaByte motherboard, so I knew it was not the Sirus. I finally resolved the issue on my Gigabyte mobo by enabling my last unused USB controller on my motherboard. This resolved my interference issue. I'm confident that this could also have been resolved by installing a PCI USB board, a better power supply to USB, or an externally powered USB hub. Once I resolved the interference issue the tonal qualities during the technical tests was superb.
Music: When it came to music, the Sirus performed well. The high pitches sounded clear, but the bass suffered slightly due to the smaller driver compared to a large stereo headset. The tones were still clear and crisp, but it couldn't pound my head if I tried. It was difficult to distinguish much difference between the USB and the TSR setups in sound quality, but I stuck with the Realtek on-board sound card. There may be more difference with a higher quality sound card. Audiophiles will probably want to stick with the 5.1 jacks as opposed to the USB interface.
Gaming: The goal for 5.1 surround sound is to provide an immersive environment. Particularly for FPS games it should be easier to pinpoint the sources of enemy gunfire and footsteps. I frequently get accused of hacking because I pay close attention to enemy sounds, I'm good at predicting behavior, and I have a quick reflex. With stereo sound I find I have to turn frequently to get a better fix on the source of a sound. With the true 5.1 provided by the Sirus I didn't have to turn nearly as much. The improvement in sound localization was obvious. Despite this improvement, I still found it hard to identify the location of sounds from directly behind from those that are just more quiet than normal. I also that the bass seemed to overwhelm many other sounds, especially the high frequency sounds. The Tactical mixing console did a good job of on-the-fly adjustment to improve sound quality. Although the software can get a more natural balance I still preferred the speed and convenience of the knob on the desktop.
Movies: The Sirus provides great improvement over stereo movies, but it doesn't quite compare to a full 5.1 speaker setup. The sound quality is the same as that provided for music, and the surround sound is decent but not as good as speakers.
Misc: The headset performed well for miscellaneous voice applications like Skype. The one problem I experienced was low mic volume. For some reason it seems like the mic doesn't get the same amount of amplification as the speakers and there always seemed to be a mismatch between the two. Noise cancellation worked okay, but it wasn't as good as it could have been because I had to turn the amplification so high in windows.