a freeware DK-meter clone
by Joachim Michaelis and Lasse Tassing

This is a great utility for measuring the sound coming into your soundcard.   help

With this tool you can analyze things like level, stereo perspective, distortion, phase trouble and frequency content. It is mostly designed for musicians, and for working with music. That's why I didn't spend a lot of time adding a scale showing Hz and dB with numbers. You should use this tool with intuition - not as a physics nerd!

So why yet another spectrum analyzer?
This tool has several advantages compared with other popular analyzing tools as found in SoundForge, CoolED, SpectraLab, etc.:

  • Peak meter (the two rightmost green bars) has a sensible logartithm, so that you can easily monitor both peak levels and noise floor.

  • Frequencies are shown logaritmic. There's still a lot of programs that show "spectrum analyzers" in a linear way (fx. WinAmp). They're pretty useless, since the ear percieves 600-800 Hz as being "in the middle". This tool shows frequences in excactly that way, using the logaritmic scale.

  • Bass - treble balance in a raw Fourier-transform shows most well-produced music as having much more bass than treble. For instance if you do a Spectrum Analysis in SoundForge on most kinds of music, you'll typically see a curve that is sloping upwards towards the left side i.e. having to much bass, and not enough treble.
    This is because the normal Fourier Transform is calibrated to show white noise as being linear. But you can't really hear any bass in white noise, can you?     ;-)
    That's because the ear expects 3 dB more energy per octave towards the lower frequencies. VUmeter.exe is calibrated to show pink noise as being linear, so music that is well produced should produce a horizontal line (more or less), when analyzed with the two FFT-meters.

  • Monitor stereo in different frequencies at the same time. This kind of analysis, I have not seen in any other program yet. Thanks to David Filskov for that idea.

  • Multi-threading ensures optimal performance on systems with more than one CPU.

    The hotkeys are simple:

  • 1...6 - jump to view
  • Esc - exit VUmeter
  • N - zoom into noise level
  • H - zoom into high frequency area

  • 1) Phase Meter

    This view shows stereo perspective. If you see a straight vertical line, you have mono.
    If you see a straight line that is tilted, you have too much signal in one side.
    The wider the "hairball" is, the more stereo you have.
    The "hairball" thingy may be as round as seen on this image, but if it gets wider than it is high, you have too much stereo.
    2) Oscilloscope

    This view is good when checking for distortion and stuff. If you see flat parts on the incoming sound on the white curve, usually at the top or bottom, you have distortion.

    You can zoom in and out using the cursor up/down keys.
    3) Syncronized oscilloscope

    This view is good for analysing the output from synths and tone generators. It waits for the waveform to restart at zero before it shows a new screen.

    Again, you can zoom in and out using the cursor up/down keys.
    4) RMS FFT-view

    This view shows frequencies using a slow averaging view of the incoming frequencies from 20 Hz to 24 KHz.

    You should try to get this curve to be as horizontal as possible. To do this, you will have to either adjust the levels of your individual instruments, or use an equalizer.
    5) Peak FFT-view

    This view shows the frequencies in a fast peakmeter-like way. You can easily follow the frequency patterns of individual instruments in this view.

    Again, the view should be somewhat horizontal, when all the instruments are playing. (Tip: Measure at the climax of the song!)

    View 3 and 4 works in the same way except for the update speed, so basically you can use them for the same things.
    6) Stereo phase FFT-view

    This view shows stereo phase through all the frequencies. Positive phase points upwards (when the left and right sides are in phase = mono), negative (left and right are out of phase = stereo) points down.

    This view does not have to show a flat horizontal curve.

    For example, if you're mastering for vinyl records, or want to ensure compatibility with subwoofer systems, you shouldn't have negative phase content in the low frequency area (leftmost red area). Hence, the leftmost part should indicate values above the center line (as shown here).

    Or in simple terms: The left third should never go below the center line!

    (For other kinds of media there may be slightly different guidelines.)
  • Default window size is now larger
  • Keyboard now changes views and settings
  • All scales (units) are now working properly
  • Wrote a FAQ
  • Full frequency range is now displayed
  • Harddisk crash! Source code is way behind
  • Requirements:
    WaveIn at 48000, 44100 or 32000 Hz samplerate
    Win95 / Win98 / Win2000 / WinNT 3.5x or higher
    (Only NT4 is well tested).
    Since I am an Amiga programmer, I cannot be held responsible if this tool should cause any damage.
    Last update: 12 Nov 2006, 12:57

    Note: If you experience strange flickering display or unstabilities,
    try the Special SoundBlaster Version

    For general or audio related questions, contact:
    Joachim Michaelis
    For programming related issues, contact:
    Lasse Tassing
    Droid Low-fi 8-bit synth that resembles a mad Commodore 64 on speed.
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