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Topic: Sound card perfomance at different sample rates (Read 34261 times) previous topic - next topic
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Sound card perfomance at different sample rates

Reply #25 –
In order not to give a false impression that native 44/48k could not make a flat response, Arnold's old website has a PC soundcard benchmark database. Just don't use today's standard to judge the results because those cards are about 10-20 years old, and some of them don't even support 48k.

http://web.archive.org/web/20061205221243/...mpare/index.htm

Also attached my VIA HD Audio's 44/48/96 results to show that it performs similarly in different sample rates. (Recorded by X-Fi Titanium HD)
http://www.hydrogenaudio.org/forums/index....ost&id=7804

Sound card perfomance at different sample rates

Reply #26 –
Quote from: greynol on
If I have a sound card that gives me adequate performance and suits my purposes using a software-based resampler because its on-board resampler isn't up to snuff, why should I replace it?  That seems wasteful.


I can agree that (I still have Audigy 2 in daily use in one of my PC's ... mostly because of its AUD_EXT connector http://pinouts.ru/Multimedia/creative_int_pinout.shtml ).

Sound card perfomance at different sample rates

Reply #27 –
Quote from: bennetng on
...

Also attached my VIA HD Audio's 44/48/96 results to show that it performs similarly in different sample rates. (Recorded by X-Fi Titanium HD)


Yes, frequency response is quite flat on some of those onboard sound codecs. I have measured the (Front L/R) output from VIA VT1828S chip (found in ASUS board) (VIA->E-MU0404USB). Frequency response (20Hz-20kHz) is quite OK for 44.1kHz and 48kHz. Hoping they fix the bit-resolution part next (for 1828S I could get for it's Front L/R output (all modes) only 87dB which means ~15-bit).

Sound card perfomance at different sample rates

Reply #28 –
Is that 87 dB due to actual noise or due to ground loop related crap in the test setup? According to test results on the web, the chip itself should be able to hit the 90s in practice. (The spec even claims up to 110 dB, and 100 dB for the ADC - try a loopback test.)

I have recently uploaded loopback test results for the Audigy FX (which employs a Realtek ALC898), rear Front L/R to Line-In. While 44.1 and 88.2 are affected by what seems to be a stupid driver bug limiting recording to 16 bit, 48 and 96 show rather respectable dynamic range approaching the 104 dB(A) ADC spec. (ADC passband ripple isn't so hot at about 0.04 dB p-p, but they've got to cut corners somewhere, right?)

Sound card perfomance at different sample rates

Reply #29 –
Quote from: Juha on
Quote from: bennetng on
...

Also attached my VIA HD Audio's 44/48/96 results to show that it performs similarly in different sample rates. (Recorded by X-Fi Titanium HD)


Yes, frequency response is quite flat on some of those onboard sound codecs. I have measured the (Front L/R) output from VIA VT1828S chip (found in ASUS board) (VIA->E-MU0404USB). Frequency response (20Hz-20kHz) is quite OK for 44.1kHz and 48kHz. Hoping they fix the bit-resolution part next (for 1828S I could get for it's Front L/R output (all modes) only 87dB which means ~15-bit).


Probably the SNR has little to do with the DAC and instead is just the board its put in.

Sound card perfomance at different sample rates

Reply #30 –
Quote from: saratoga on
Quote from: Juha on
Quote from: bennetng on
...

Also attached my VIA HD Audio's 44/48/96 results to show that it performs similarly in different sample rates. (Recorded by X-Fi Titanium HD)


Yes, frequency response is quite flat on some of those onboard sound codecs. I have measured the (Front L/R) output from VIA VT1828S chip (found in ASUS board) (VIA->E-MU0404USB). Frequency response (20Hz-20kHz) is quite OK for 44.1kHz and 48kHz. Hoping they fix the bit-resolution part next (for 1828S I could get for it's Front L/R output (all modes) only 87dB which means ~15-bit).


Probably the SNR has little to do with the DAC and instead is just the board its put in.


IME a godly number of chips have asymmetrical performance, and the only way to test the full potential of the DAC is to use the ADC on a board with higher, symmetrical performance such as most of the pro cards.

Sound card perfomance at different sample rates

Reply #31 –
Also a very good point, but I think the E-MU0404USB he used was probably good enough.

Sound card perfomance at different sample rates

Reply #32 –
The more "external" you get, the bigger the ground loops though, hence my question. Dedicated audio analyzers have galvanically isolated inputs and outputs for good reason. The 0404USB itself gets 113 dB(A) in loopback, that ought to do. One may just have to include an isolation transformer or determine output impedance and build a pseudo-balanced adapter that reroutes output ground to the "cold" input via a resistor of determined value (per channel).

Of course some ground loops or other performance-degrading issues may already be present on the board itself. It may also be beneficial to disconnect the front panel audio if that poses ground loop problems.

Sound card perfomance at different sample rates

Reply #33 –
A member used 0404USB to test Fuze+ and got -98dB in RMAA so I think 0404USB should be good enough.
http://www.hydrogenaudio.org/forums/index....=0&p=833017

0404USB spec:
http://www.creative.com/emu/products/product.aspx?pid=15185
   - Input Impedance: 1Mohm
   - Max Level: +12dBV (14.2dBu)
   - Dynamic Range (A-weighted, 1kHz, min gain): 113dB
   - Signal-to-Noise Ratio (A-weighted, min gain): 113dB
   - THD+N (1kHz at -1dBFS, min gain): -101dB (.0009%)

And this is the self loop result of my X-Fi Titanium HD, different sample rates have similar results.
http://www.hydrogenaudio.org/forums/index....howtopic=100481

I don't know the exact formula to convert dBV to Vrms but X-Fi series' I/O are at 2Vrms maximum, 5dB digital gain is needed to match my VIA HD audio's RMAA test signal which is not shown in my reports because I adjusted the digital gain in my X-Fi's mixer already.

Sound card perfomance at different sample rates

Reply #34 –
Quote from: stephan_g on
Is that 87 dB due to actual noise or due to ground loop related crap in the test setup? According to test results on the web, the chip itself should be able to hit the 90s in practice. (The spec even claims up to 110 dB, and 100 dB for the ADC - try a loopback test.)  I have recently uploaded loopback test results for the Audigy FX (which employs a Realtek ALC898), rear Front L/R to Line-In. While 44.1 and 88.2 are affected by what seems to be a stupid driver bug limiting recording to 16 bit, 48 and 96 show rather respectable dynamic range approaching the 104 dB(A) ADC spec. (ADC passband ripple isn't so hot at about 0.04 dB p-p, but they've got to cut corners somewhere, right?)


Actually, as I got about same DR results for ESI DuaFire I took a closer look after possible reason for this. Finally got the DR improved for both by placing the E-MU as far away from PC gear and power leads as possible (no cable crossings, etc). The DR resuts for VIA codec stayed <93dB for 16-bit modes and <98dB for 24-bit modes.


Quote
Probably the SNR has little to do with the DAC and instead is just the board its put in.
- yes, from me it was just a side note.
   

Sound card perfomance at different sample rates

Reply #35 –
Assuming the external device is USB powered off the same PC, a ground loop is probably not too serious of a problem.

Sound card perfomance at different sample rates

Reply #36 –
Quote from: saratoga on
Assuming the external device is USB powered off the same PC, a ground loop is probably not too serious of a problem.


Ground loops are possible even between different parts of the same PC (for example, a USB port and an internal sound card). This can be seen on these graphs that show all possible loopbacks between two sound cards installed in the same computer. The cases when the ADC and the DAC are not on the same card are significantly noisier. Adding a simple differential amplifier to the loopback fixed the ground noise in another test.

Sound card perfomance at different sample rates

Reply #37 –
Quote from: stv014 on
Quote from: saratoga on
Assuming the external device is USB powered off the same PC, a ground loop is probably not too serious of a problem.


Ground loops are possible even between different parts of the same PC (for example, a USB port and an internal sound card). This can be seen on these graphs that show all possible loopbacks between two sound cards installed in the same computer. The cases when the ADC and the DAC are not on the same card are significantly noisier. Adding a simple differential amplifier to the loopback fixed the ground noise in another test.


Interesting.  I suppose the most likely explanation is that one of those cards uses a virtual audio ground that is significantly different than the other.  I've seen this in car stereos with MP3 players where the stereo virtual ground is several volts different than the virtual ground generated from the low voltage battery regulator, resulting in extreme interference.

Sound card perfomance at different sample rates

Reply #38 –
From a quick test with a multimeter, the ground of the input and output jacks of both cards seems to be connected to the chassis of the PC. But many other devices (motherboard, graphics card, power supply, etc.) are also connected to the chassis, which is why it is noisy.

Sound card perfomance at different sample rates

Reply #39 –
Just curious and installed my old X-Fi XtremeMusic then recorded by X-Fi Titanium and got -109dB which is same as the advertised spec. Creative is really quite honest (in some aspects )
http://www.hydrogenaudio.org/forums/index....st&p=858334

Sound card perfomance at different sample rates

Reply #41 –
Quote from: stv014 on
From a quick test with a multimeter, the ground of the input and output jacks of both cards seems to be connected to the chassis of the PC. But many other devices (motherboard, graphics card, power supply, etc.) are also connected to the chassis, which is why it is noisy.



Common grounding does not necessitate noise. How the common grounding is accomplished, IOW the exact routing and sizing of circuit board traces can matter a great deal.

There is an area of electrical engineering called mixed signal design which addresses this among a great number of other things. It is composed of both art and science.

I've improved the SNR of a piece of commercial audio gear by up to 20 dB by redoing a very few land patterns on a certain circuit card, and this isn't even my thing!

Sound card perfomance at different sample rates

Reply #42 –
My Xonar DS has terrible ultrasonic performance, I get an audible tone near the 4-5k area if I play a ~44kHz sinewave

The internal DSP (all settings, 44.1/48/96/192 same result) must lack any sort of anti-aliasing on its LPF, though why it applies a LPF in the first place, I have no clue.

I make sure I have Windows set to 48kHz as it has a functional LPF for the rare occasion I ever come across high sample rate content.

Sound card perfomance at different sample rates

Reply #43 –
Terrible. Are you getting the same result in different APIs (ASIO/KS/MME/DS/WASAPI)?

Sound card perfomance at different sample rates

Reply #44 –
I'm recording with sox, but played the file back with Foobar2000 (WASAPI?) and sox(MME?), both produce the same spectrogram, play back of a 44kHz tone with foobar is also audible.

Sound card perfomance at different sample rates

Reply #45 –
Have you applied the Windows 7 MME resampling patch?  http://support.microsoft.com/kb/2653312  (of course, If you are using Windows 7..)

Sound card perfomance at different sample rates

Reply #46 –
I suspect it is some kind of Windows sample rate conversion issue, which can be difficult to avoid or fix sometimes, depending on the drivers. Although I only have the Xonar D1 as a reference, which is a one step higher model, the hardware is similar other than the better DAC, and it performs much better (tested on Linux). Also, I have seen RMAA results of the cheap Xonar DG with flatter frequency response. Even onboard codecs should be better than that. It is almost certainly a software problem.

Sound card perfomance at different sample rates

Reply #47 –
I was making some tests, and there are quite a few places where things can go wrong. (Edit: this is a realtek ALC268 HDAudio integrated laptop soundcard)

I made a sweep signal with audacity from 100Hz to 47999Hz , logaritmic, 10 seconds, amplitude 0.97 (-0.3dBFS approx). The project setting was set to 96Khz.
I played it inside audacity using the WASAPI driver. (audacity 2.0.5)
I recorded with sox with the line:  sox -d -c 2 -b 24 -r 96000 record.wav  (sox 14.4.1)

The default recording device was set to stereo mix. The stereo mix was set to 44Khz 16bits. The Windows 7 MME patch is applied.
Sox decided to record at 48Khz 16bits.

So the audio did 96Khz->44Khz->48Khz->96Khz. It had some aliasing, but it did not bounce back.

When I realized that, I changed the stereo mix to 96Khz.
And then the audio did 96Khz->96Khz->48Khz->96Khz (yes, sox still decided to record at 48Khz). Now, the aliasing was almost nonexistant and of course it did not bounce back either.

And that is without even adding the DAC and ADC into play... go see...


Edit: Ok, I realized the way to specify the samplerate of the wave input is adding it before the -d switch:  sox -r96000 -b24 -d -c 2 -b 24 -r 96000 record96-96-96-stereo_mix.wav  Now i had quite a clean signal with a slight lowpass filtering from a bit before 40Khz. (slight as in I see the waveform amplitude decreasing. It decreases in 10dBs at 48Khz)

Edit2: Seems audacity has a bug and stops the audio too soon. I had to add a second of silence at the end because else the sweep was cut at 45Khz or so.
Also, I've finally tried with a loopback cable and it acts like the stereo mix. In fact, even better, because the stereo mix had noise shaped dither.

Sound card perfomance at different sample rates

Reply #48 –
The image doesn't look like Win7's bad MME resampling because linear interpolation before applying the hotfix will generate reflections all over the graph like this
http://src.infinitewave.ca/images/Sweep/SRC_Lin.png

I guess it is caused by Asus' driver/software issues. Try to use ASIO4all to see if there are any improvement or not. See

http://www.hydrogenaudio.org/forums/index....st&p=829916