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Due to the dearth of sound card "loading" tools available, power
consumption was measured only at idle. While we can make guesses about which
tasks are most power intensive, there is no easy way of isolating those tasks
from the stress they put on the other parts of the system. Spot checks during
simple stereo playback did not reveal a significant boost in power consumption
Asus Xonar HDAV1.3 Deluxe
Estimated power consumption
Base System +
Even at idle, the power gobbled up by the HDAV1.3 is significant. While not
in the same league as power hungry graphics cards, it did eat up about 11W at
idle, increasing the total power consumption of our modest test bed by about
Objective Test Results
It is tempting to simply state that the acoustic characteristics of the Xonar
HDAV1.3 are excellent and leave it at that. So called "objective"
testing is difficult to do well, and SPCR has no existing body of results to
use as a baseline. While Rightmark's Audio Analyzer (RMAA) is a useful, standardized
tool, it is difficult to use correctly and interpret the results in a meaningful
A proper lab test using RMAA would test each input and output in isolation
using reference equipment with known audio characteristics that are significantly
better than the card being tested. Ideally, the test suite would include multiple
reference levels and usage patterns. Unfortunately, advanced though the SPCR
lab is, we are not set up to do this kind of advanced electronic testing.
So, we offer a compromise. RMAA has a test mode called external loopback testing
in which the output of the card is looped back into the input via an external
cable. The test suite is then run, and the results include the performance characteristics
of both the input and the output sections of the card. Whichever section has
the worst performance will limit the results, but, barring distortion in one
section that is corrected by the other, both the input and the output should
be guaranteed to have performance at least as good at the test results.
Some other problems with the test:
- Ideally, tests should be done either at the maximum output the card can
provide (to maximize the possible signal-to-noise ratio and thus test all
devices to their maximum potential), or at a predetermined set level (to provide
a standardized test across all models perhaps at the Redbook CD Audio
"line" level of +6 dBV). The RMAA loopback test does not allow output
levels to be set properly.
- The RMAA tests do not test typical usage scenarios, in which the card's
mixer, DSP, and levels can all affect audio performance.
So, with those caveats, we present the results of our loopback test for 96
kHz, tested at bit depths of 16, 24, and 32 (int). Only a portion of our RMAA
test data is reproduced here. Those who are interested may download
our complete set of results, including every combination of sample rates
and bit depths from 44.1 to 192 kHz and 16 to 32 bits. The SAV files included
in the results may be opened with RMAA, downloadable
from Rightmark's web site.
Frequency response is flat to ±0.05 dB from 20~20,000 Hz.
The noise floor is about -117 dB for 24 and 32 bit depths, and -100 at 16
|Test @ 96 kHz
|| 16 bit samples
||24 bit samples
||32 bit samples
|Frequency response (from 40 Hz to
15 kHz), dB:
|Noise level, dB (A):
|Dynamic range, dB (A):
|IMD + Noise, %:
|Stereo crosstalk, dB:
The results at 24 bit / 96 kHz are representative of the card's performance
overall. Tests at 44.1 kHz or with 16 bit samples showed worse performance,
but this reflects on the limitations of these formats, not on the card itself.
We are still scratching our head trying to figure out how our 16 bit results
managed to exceed the maximum theoretical noise level for 16 bit audio (96 dB).
wikipedia article suggests that the 96 dB number is based on assumptions
about the digital-to-analogue conversion, so perhaps the results are a reflection
of higher quality DACs ... or perhaps they indicate a problem with RMAA's tests.
At 48 kHz or 24 bits and above, performance was essentially the same for all
audio formats, suggesting that these results are the true representation of
the card's abilities (most likely limited by the performance of the inputs).
It also suggests that the performance (at least as far as noise is concerned)
exceeds what is required to play back the vast majority of audio sources (which
are 16 bit) "perfectly".
Obviously, noise is not the only concern, but the frequency response and various
distortion tests were also universally excellent. Frequency response was essentially
flat through the entire audible range, and THD and IMD were barely measurable.
It should be noted that our results more or less duplicate those obtained by
Asus in their own
RMAA tests. We know of two other sites that have done RMAA tests on the
HDAV1.3, both of which produced different (and worse) results from our own.
Elite Bastards examined
the card here, while Atomic PC obtained results so bad as to throw their
methodology into question in
this review. In fairness to Atomic PC, we obtained similar results in our
first attempt by routing the signal internally by recording the "Wave"
input. Most likely, the poor results are a result of audio mangling within the
operating system and not a reflection on the hardware, but it does illustrate
that there are many factors that affect audio performance beyond the
All of our RMAA tests were done with the line-in level at 100 and the output
level at 40. Why 40? This was the only level we could get which was high enough
for RMAA to test but low enough not to cause serious distortion at the input.
This caught our attention, because we also noticed serious distortion at the
outputs when doing our speaker tests during setup. So, we decided to investigate
by pulling out our multimeter and actually measuring the output levels
electronically. And this is what we found...
At 100 (maximum) volume, our 1 kHz test tone (recorded at -3.2 dBFS, or 3.2
dB below the maximum possible level) measured 2.26 VRMS. That's a
lot. In fact, the standard line level for RCA outputs is a mere 0.316 VRMS.
Expressed in decibels, the standard line level is -10 dBV, while the Xonar was
outputting +7dBV. Adding in the potential 3.2 dB that could be gained by maximizing
the test tone brings the difference between the Xonar's output and the expected
line level to a whopping 20 dB. No wonder the output was clipped. Have pity
on the poor pre-amps that have to accept such a hot signal.
Now, to be fair, the line level is just a guideline; many products do not meet
it exactly, and all designs allow for some headroom. Unofficially, many devices
follow the Redbook audio standard such that the loudest possible signal is output
at +6 dBV (2.0 VRMS), a headroom of 16 dB. At +10 dBV, the Xonar's
maximum output isn't that much higher than the unofficial standard, but
it was high enough to cause distortion in situations where there shouldn't have
been any. We did notice that the Xonar's driver software correctly reports the
peak of the graphic equalizer as +20 dB. We also verified that a 0 dB peak on
the equalizer correctly output a line level signal of roughly 0.322 VRMS.
But folks, we have to warn you, blasting the HDAV1.3 at full volume into a substandard
amplifier or receiver could permanently damage your equipment.
Further investigation revealed that the "40" volume setting that
we used during the RMAA tests yielded an output level of 1.427V, or +3 dBV.
This suggests that the line-in (which clipped above this level) is not quite
up to the task of accepting a full strength signal from a CD player or any other
device with peaks above +3dBV.
We also noticed that, while boosting the volume from 40 to 100 increased the
output voltage by almost a volt, the level in decibels increased only by 4.
This behavior is indicative of the fact that the volume control in the Xonar
control panel sets the volume linearly, not logarithmically as it should.
The practical effect of this is that it is extremely difficult to set low volumes
reliably. For example, consumer line level (the level at which you'd be guaranteed
not to clip most consumer electronics) can be set at about ~13.5 on the volume
meter, but it is difficult to set with any precision.
Xonar HDAV1.3 Output Levels
Maximum Output (Calculated)
Maximum Output with Test Tone
Maximum Level of Unofficial "Redbook" Standard
RMAA Test Level
"Consumer" Line Level
With this new knowledge in hand we can revisit the results from the RMAA test
and see why they aren't as reliable as they might seem. Tested with the volume
set to 100, the HDAV1.3 could potentially show a 7 dB greater dynamic range
and signal to noise ratio (never mind that a recording with 124 dB of dynamic
range could blow your eardrums if you listened to it). On the other hand, even
if it could output the signal cleanly without distortion (and distortion increases
as output goes up), its high output level is likely to cause distortion in whatever
is plugged in to it.
By the same token, if it was tested at consumer line level (when the equalizer
peak is 0dB), the incredible 117 dB SNR would magically drop to 104 dB. In theory,
this is the level that should provide the best possible analogue performance,
allowing plenty of room for transient peaks. Not only will distortion drop at
lower levels, but keeping the levels closer to where other devices expect them
to be should help avoid distortion further down the signal chain.
The vulnerability of RMAA's test results to variable line levels makes us speculate
whether this is the reason for the HDAV1.3's high output levels. Boosting levels
is an easy way to artificially inflate signal to noise ratios (it's one of the
reasons why "pro" line is 12 dB higher than "consumer" line),
and it would not surprise this reviewer to learn that the practice is widespread
among all high-end audio cards. And, so long as the rest of the equipment in
the signal chain is also designed for levels with 20 dB of headroom above "standard"
line, this kind of design can offer a measurable improvement in SNR. However,
we repeat our caution that high line levels can damage equipment that
is not designed for this kind of signal.
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