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SoundBlaster users - Please run this simple test to help me.

By vivona ยท 8 replies
Dec 29, 2005
  1. I have been trying to solve a problem with my Audigy 2 ZS PCI card. If I record a sine wave at 16bit-48k and set the recording level so that the peaks just reach full amplitude (100% or 0VU), then without changing the recording level if I change to 16bit-44.1k and record, the peaks are about 5% lower. Normally, this wouldn't be much of an issue, but if I try to increase the recording level, the peaks clip at that level instead of the 0VU level one would expect.

    As I understand it, the Audigy initially digitizes at 48k. If you want to record at a lower rate, such as 44.1k, the card has a recording sample rate converter (SRC) that resamples the 48k signal down to 44.1k. In that process the audio level should remain constant, and it has in many other SoundBlaster cards I have worked with. But in my Audigy the level drops 5%. What I am seeing when I see clipping at 95% of full scale at 44.1k is the actual 0VU digital clipping that had occurred at the initial 48k sampling. The important thing to note is that this only happens with 16-bit recordings. 24-bit is okay.

    This becomes a problem because I cannot use the peak indicator on the VU meter to warn of clipping when recording at 16bit-44.1k. No matter the level, the peak indicator will never light because the audio level never reaches 0VU.

    I had tried other versions of Audigy 2 ZS drivers and one version actually made the problem worse, making 44.1k peaks clip at 90% of full scale. So this seems to be a driver issue related to the SRC process during recording. I have been communicating with Creative's Advanced Support Group on this problem, but they cannot duplicate it, so they can't offer any help.

    Here's how you can help:

    1. There are about 25 files involved in the Audigy driver set. If you know the specific driver file(s) that affect recording SRC in the Audigy, please let me know. If I can isolate this to a file or two, perhaps Creative can solve my problem.

    2. It would be very helpful if you would run a simple test if you have an Audigy, or any other SoundBlaster for that matter, and report back here. All you have to do is feed some audio in your line-in connector and begin recording at 16-bit, 48K (make sure of that setting). Increase the audio level until it clips heavily. Stop recording and look at your recorded waveform to verify that it is clipped at 0VU (100% of the possible amplitude). Now, without changing the recording level, change your recording setting to 16-bit, 44.1k and record again. Stop recording and look at the waveform. Does it clip at the same level, 0VU, as the 48k recording, or does it clip at a lower level, about 5 to 10% lower than before?

    I am using percentages because many recording software doesn't have a dB scale on the recorded waveform, but it is very easy to estimate by eye if a waveform is 5% or 10% lower.

    This proplem happens for me regardless of if I record from line-in or record a wave file being played back by Windows Media Player, so it has nothing to do with the analog audio level at the line-in connector.
  2. vivona

    vivona TS Rookie Topic Starter

    Summarized Request

    So far a lot of readers, but no replies. If you don't want to read through all of the background information in the original post, just run the folowing test and report your results in a reply to this topic. I should only take you a few minutes. I would really appreciate your help.

  3. vivona

    vivona TS Rookie Topic Starter

    I thought I would get some responses...
  4. DragonFury

    DragonFury TS Rookie Posts: 61

    what u tring to record ? or tring to find out ?
  5. vivona

    vivona TS Rookie Topic Starter

    I rip wave files from Karaoke CD's, or record waves files from Karaoke tapes. Then, using multitrack recording software, I record my singing along with these tracks and mixdown to create albums of my vocal performances. I prefer to record in 16-bit, 44.1k for file size considerations, compatability with the CD format and the fact that a speciality wave editor I use is limited to 16/44.1.

    With virtually every other soundcard I have used, when recording at 16/44.1k, from any source (line-in, wave playback, etc.) if the audio peaks reached 100% (0dBfs) the peak indicator on the recording software VU meter would light up, warning me of clipping. I could easily get the hottest recording without clipping with just a few passes through the loudest parts of the recording source to set levels.

    When I changed to the Audigy, I found that with 16/44.1k the VU meter would not reach 100% no matter how high the recording level. I was getting clipping at 95% of full scale instead of 100%. It is hard to see all peaks on a VU meter alone, so it is now difficult to set recording levels at a reasonably high level and be sure I am not clipping. I lose the benefit of the peak indicator. I now have to search the waveform for the highest peaks after recording and make sure they did not reach the 95% clipping level. That is time consuming.

    I am trying to find out if some, or all, Audigy 2 soundcards have the same problem. If I get many responses that report the problem, it makes it more likely that this is a defect with the card's design or drivers. If many responses say they don't have the problem, it points to something particular to my installation. I am trying to get Creative support to resolve the issue, but they can't duplicate the problem as of yet. I have provided them with screenshots and detailed testing information and am awaiting their response.

    I had thought the users at TechSpot would be very resonsive in trying my simple test. Surely, there are Audigy 2 users reading this forum. It has been disappointing that I have not received any test reports.
  6. Ruder

    Ruder TS Rookie Posts: 98

    The cards have the same problem. Your problems are the least of it.

    If Creative have not solved the problem yet, it is not the drivers, but a hardware problem.

    Get another good quality card ...
  7. vivona

    vivona TS Rookie Topic Starter

    ruder - I just heard back from Creative. They reviewed the hardware contents of my PC and contend that my power supply is overloaded. They say the problem I am having with my Audigy is due to the overloaded power supply. Is that conceivable - that the 44.1k recording would be reduced by 5%, but all other sampling rates would be fine?

    Based on a rule of thumb that Creative uses, they say my load is 360 Watts. Based on the calculator at http://www.extreme.outervision.com/index.jsp, my load is 300 Watts. My power supply is rated at 375 Watts. This evening I am going to measure actual current draw of the PC itself. Amps drawn times 120v should tell me the overall wattage drawn by the power supply. If the draw is a lot less than 375 Watts, the power supply cannot be overloaded because the power supply itself uses some of the current draw in its own operation.

    Another test would be to remove the second SATA drive, USB devices and the dialup modem which should remove about 25 watts and see if the Audigy behaves any differently. I'm betting it doesn't.
  8. vivona

    vivona TS Rookie Topic Starter

    I fully tested the power supply draw and all voltages. Everything is well within spec. The power supply is not the problem.

    I think this is really a design or driver defect with the Audigy. It is like pulling teeth to get someone to actually take a few minutes to run the test to verify if other Audigy users see the problem.

    If I ultimately decide to scrap the Audigy, and want to keep SoundFont capability for MIDI, my only other choice would be the X-Fi, but I need to be sure it doesn't have the 44.1k problem. Any X-Fi users willing to test and reply?
  9. vivona

    vivona TS Rookie Topic Starter

    No one has tested and responded. I was hoping that I could determine whether this was a design defect with all Audigy 2 ZS cards, or something specific to my installation. The ads for the X-Fi claim to fix 44.1k problems, so testing by an X-Fi user would also help me.

    I chose the Audigy because I also use SoundFonts and I don't know of other cards that support SondFonts. Also, the Audigy has a FireWire port, so that saved a PCI slot.

    So, why no responses? I am open to ideas on how to get readers to actually take a few minutes to help. Isn't that why we use these forums?
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