Topic: Creative X-Fi HD USB SB1240 Measurements (DAC - External Loopback) (Read 5941 times)

Hands · « **on:** December 26, 2013, 04:43:31 PM »

I wanted to post more measurements of this unit for completeness, since it is currently what I use as my ADC when measuring other gear. As such, any other measurements I do using this as the ADC will be limited by this unit's performance, and these measurements can act as some sort of reference for what those limitations are. And, since this is a loopback that tests the DAC and ADC in the unit, ADC performance by itself should only be better than what is seen in the context of these measurements.

This post also shows some of the new approaches I'm taking to measurements compared to the ones I did for the Metrum (which I hope to revise), mostly when using ARTA. Jitter measurements are now included using JTest files. Spectrum measurements should be much more informative now, and I've also decided to not follow up with further sine wave response measurements on DACs (details below).

Do note that when looking at my measurements, I do NOT always set scales and zooms to match 1:1 across measurements. For example, with impulse responses, I'll scale and zoom to get the best depiction of the information I can.

Refer to the Metrum Quad DAC measurements thread for any other detail I might have missed.

I've attached a ZIP file of what should be all the tests I have of this unit, some of which I did not post on here.

Test Hardware and Setup

1. Acer Aspire 5560G Laptop - Locked at 1.4GHz and 0.9125V via K10Stat, dedicated GPU disabled, internal fan disconnected (low temps and stability verified), most Fidelizer tweaks applied, and other hardware, software, and services disabled.

2. Creative X-FI HD USB (SB1240) - External loopback tests done with BJC 6' RCA cable, powered by USB bus, connected to Acer laptop. Unit is limited to 48/96KHz input/output.

Software

Rightmark 6.3.0 and ARTA

Links

Creative SB1240 - http://us.creative.com/p/sound-blaster/sound-blaster-digital-music-premium-hd
RightMark Audio Analyzer - http://audio.rightmark.org/index_new.shtml
ARTA: http://www.artalabs.hr/

Hands · « **Reply #1 on:** December 26, 2013, 04:46:07 PM »

JTest 24/48 file with hardware and software set to 24/96 (did this to match my NOS1704 tests, did not see a difference running hardware and software in 24/48). Did my best to match Marv's latest jitter measurements. Used JRiver Media Center for JTest file playback (no software upsampling).

Hands · « **Reply #2 on:** December 26, 2013, 04:48:12 PM »

1. 1KHz Sine Wave Spectrum at 24/96
2. 100Hz Sine Wave Spectrum at 24/96
3. 60Hz and 7KHz Dual Sine Wave Spectrum at 24/96
4. 25Hz and 66KHz Dual Sine Wave Spectrum at 24/96
5. Noise at 24/96

Hands · « **Reply #3 on:** December 26, 2013, 04:52:28 PM »

1. Periodic impulse response. Notice the bit of post-ringing relative to a NOS DAC.
2. 1KHz square wave response. Also shows additional ringing vs. a NOS DAC.
3. 20KHz sine wave response. This shows the same characteristics as the Metrum Quad NOS DAC at 20KHz, and I'm not knowledgeable enough to explain what's going on here. Thus, I'm not going to be running sine wave response tests for the foreseeable future on DACs.
4. FR and distortion graph generated by a sweep impulse response. Much like the Metrum DAC, no idea if this is value at all or not but figure it won't hurt to post.

Hands · « **Reply #4 on:** December 26, 2013, 04:56:46 PM »

For completeness and convenience, I will post the 16/48 and 24/96 RightMark measurements.

Frequency response (from 40 Hz to 15 kHz), dB | +0.02, -0.08 | Excellent
Noise level, dB (A) | -92.2 | Very good
Dynamic range, dB (A) | 87.8 | Good
THD, % | 0.0028 | Excellent
THD + Noise, dB (A) | -82.2 | Good
IMD + Noise, % | 0.011 | Very good
Stereo crosstalk, dB | -89.4 | Excellent
IMD at 10 kHz, % | 0.012 | Very good
General performance | Very good

Files attached:

1. Frequency Response
2. Noise
3. Dynamic Range
4. THD
5. IMD
6. Crosstalk
7. Swept IMD

Hands · « **Reply #5 on:** December 26, 2013, 04:59:57 PM »

RightMark 24/96

Frequency response (from 40 Hz to 15 kHz), dB | +0.01, -0.08 | Excellent
Noise level, dB (A) | -98.4 | Excellent
Dynamic range, dB (A) | 98.6 | Excellent
THD, % | 0.0016 | Excellent
THD + Noise, dB (A) | -89.5 | Good
IMD + Noise, % | 0.0045 | Excellent
Stereo crosstalk, dB | -90.9 | Excellent
IMD at 10 kHz, % | 0.0049 | Excellent
General performance | Excellent

xnor · « **Reply #6 on:** December 26, 2013, 06:07:09 PM »

Quote from: hans030390 on December 26, 2013, 04:52:28 PM

1. Periodic impulse response. Notice the bit of post-ringing relative to a NOS DAC.
2. 1KHz square wave response. Also shows additional ringing vs. a NOS DAC.
3. 20KHz sine wave response. This shows the same characteristics as the Metrum Quad NOS DAC at 20KHz, and I'm not knowledgeable enough to explain what's going on here. Thus, I'm not going to be running sine wave response tests for the foreseeable future on DACs.
4. FR and distortion graph generated by a sweep impulse response. Much like the Metrum DAC, no idea if this is value at all or not but figure it won't hurt to post.

You're plotting the samples with linear interpolation here and you're bandlimiting the output of the DAC with the ADC filter.

1. More post-ringing means that the filter is not a linear phase one but a minimum or mixed phase one. Problem here again is linear interpolation between sample values. The real impulse response of the DAC looks quite a bit different.
Maybe you should plot the spectrum (magnitude and ideally group delay) of the recorded impulse, so people can see what the filter is really doing.

2. Again, maybe show the spectrum. The ringing has to be there to satisfy the sampling theorem.

3. The problem is that you're not looking at the analog waveform the DAC is outputting and again the linear interpolation between sample values.
You'd need a much higher sampling rate with the ADC to see what the DAC is doing.
If the spectrum shows that the 20 kHz sine wave is output at full level then chances are that the DAC isn't doing anything fishy.

4. FR is very important, as is THD.

Hands · « **Reply #7 on:** December 26, 2013, 06:34:18 PM »

OK, thanks for the explanations. I thought maybe it was something related to that based on our previous discussions, so that's good to finally have a better grasp on. I'll have to figure out how to do spectrum measurements with these. I toyed around with some options but am still learning most of this stuff and couldn't figure it out exactly. If you or anyone else has tips on how to set that up, I'd greatly appreciate it and will try to revise my measurements. Any other suggestions or revisions I should make? I do get that I'm fairly limited with my hardware and software at this point (I'm considering a nicer ADC for the future).

I understand that FR and THD are important, but I can't say I understand exactly how those measurements are done. I just know there are different approaches that can be taken for measurements, hence me not being sure if the sweep impulse method is valid for DAC FR/THD measurements. I'm just a bit ignorant is all.

ultrabike · « **Reply #8 on:** December 26, 2013, 07:20:00 PM »

I'm not that knowledgeable in ARTA and RMAA. I had problems calibrating ARTA, and could only work with it at 96k/24bits w the 2i2. RMAA only at 44 & 48k. I'll try to figure it out and do better myself.

However, one other thing that could be happening w the sine wave capture is that 96k is not an integer multiple of 20k. So one might get samples at different phases. I think the LCM of 96 and 20 is 480, which is 24 times 20. So about every 24 samples, things might repeat.

The sawtoothness is indeed likely the result of linear interpolation. A higher order interpolation approach (cubic or splines), or upsampling w interpolation filters to the video resolution might yield better visual results at the expense of complexity. I'm not sure, but don't think ARTA and RMAA offer these interpolation alternatives.

firev1 · « **Reply #9 on:** December 27, 2013, 02:10:39 AM »

will post my set of measurements this weekend of the same unit. It is my main dac till I get something in the mid tier :/

Author Topic: Creative X-Fi HD USB SB1240 Measurements (DAC - External Loopback) (Read 5941 times)

Hands

Creative X-Fi HD USB SB1240 Measurements (DAC - External Loopback)

Hands

SB1240 Jitter Tests - 24/48

Hands

SB1240 Spectrum Tests - ARTA

Hands

SB1240 Misc. Tests - ARTA

Hands

SB1240 16/48 - RightMark

Hands

SB1240 24/96 - RightMark

xnor

Re: SB1240 Misc. Tests - ARTA

Hands

Re: Creative X-Fi HD USB SB1240 Measurements (DAC - External Loopback)

ultrabike

Re: Creative X-Fi HD USB SB1240 Measurements (DAC - External Loopback)

firev1

Re: Creative X-Fi HD USB SB1240 Measurements (DAC - External Loopback)

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Author Topic: Creative X-Fi HD USB SB1240 Measurements (DAC - External Loopback) (Read 5941 times)