Test Tone CD Tip

Discussion in 'Archived Threads 2001-2004' started by Rick Mostaert, Dec 19, 2001.

  1. Rick Mostaert

    Rick Mostaert Auditioning

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    I have just started to build a home theater in my basement and have already received lots of tips by just reading the forum. So before I start asking a lot of questions I thought I would share a couple of tips on burning your own test tone CD quickly and removing those annoying "pops" at the beginning and end of the sine wave tone that you get using NCH.
    I used 4 programs to do this.
    1) NCH tone generator http://www.nch.com.au
    2) Generic WAV recorder for my soundcard
    3) Trial version of Supersonic http://gosupersonic.com
    4) Roxio easy CD creator
    First I generated a bunch of 7 second Sine waves using the NCH tone generator and saved them. It didn't take long to record about a hundred different frequencies. 7 seconds was long enough to get and write down a reading from the SPL meter. I also recorded a short intro, "X Hz to Y Hz," to a group of 5 tones with a Mic hooked up to my sound card so I could create different tracks on the CD. This makes it easy to repeat small sections of frequencies and know exactly what you are listening to.
    Next I went ahead and combined the voice introduction and related frequencies into individual tracks using the CD burner software. I started out using a WAV editor to append each WAV file together to make my tracks but this was taking too long. Doing it with Easy CD Creator was much faster. Plus, I ended up having to edit every tone WAV file to remove the "pops" and because Easy CD Creator reads the individual WAV files from the hard drive before writing I didn't have to manually recombine track WAVs.
    If you have used the NCH tone generator you may have noticed that the beginning and end of each tone there is usually a quick loud and nasty sounding "pop" noise. Besides this being really annoying especially at loud volumes, I was thinking that this may not be good for my speakers. I opened up a WAV editor program and noticed that the sine wave usually didn't end or begin at the zero crossing. Don't know the technical term but this discontinuity in the waveform was causing the loud noise. I edited the wave form to make sure the waveform started and ended at the zero crossing. This eliminated the noise. While this fixed the problem, it would have taken all day to individually fixed this on all of the over 100 hundred files. This is where Supersonic came in very handy.
    Supersonic has the ability to perform batch operations on groups of wave files. Since there was no way to find the zero crossing and delete part of the wave form, I used the fade function to gradual increase the amplitude of the waveform. I started the batch processing and faded from 0% to 100% for the first 5% of the WAV file and from 100% to 0% for the last 5%. Don't select a part of the waveform but use the selection buttons. You may want to practice doing it a couple of times because the faster you actually teach Supersonic, the faster it will process the rest of the files. Once you quickly perform this on one file, hit the batch button again and select the rest of the tone files. Supersonic will then add the fades to all of the files. Select "fastest" processing to do this quickly. It took about 20 minutes to completely remove all of the pops from over 100 tones and as a bonus I have a noticeable transition between frequencies.
    In addition to individual sine wave tones, I added pink noise at 1/3 octave steps, a white noise tone to set my reference dB reading, and some slow and fast low frequency sweeps to the CD. I download these WAV files that somebody was nice enough to post to the web and mention it on this forum. I have found this CD useful in benchmarking and tweaking my audio and it took me about an hour once I figured out what I was doing.
    Rick
     
  2. Brian Fellmeth

    Brian Fellmeth Supporting Actor

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    Outstanding, helpful post. Thanks.
     
  3. JackIR

    JackIR Stunt Coordinator

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    Very nice . I've been looking for something like this to help EQ my sub. Thanks Rick !!
     
  4. Chris PC

    Chris PC Producer

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    Geez, you just reminded on of the reasons I picked up a Plextor burner for my PC [​IMG]
     
  5. Dzung Pham

    Dzung Pham Second Unit

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    Rick, any chance you would be willing to post your resulting wav files on the web somewhere? Either way, thanks for sharing how you generated them.
     
  6. Dzung Pham

    Dzung Pham Second Unit

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  7. Rick Mostaert

    Rick Mostaert Auditioning

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    Dzung,

    Thanks for the link. Couldn't find that link when I was writing the initial post. That is where I found the pink noise tones and I found it after I already built and edited the bass sine waves. If you have a fast link, (I don't, still living with dial-up) it would be faster to download that MP3 file. You can then convert to WAV and break up the tones into individual tracks. I found having different labeled tracks to be very helpful. Can't quite figure out the frequency from just listening. Not yet, anyway.

    Chris,

    Just recently got the Plextor 16/10/40 and so far this is the only thing I used it for. Couldn't pass it up, paid $140 for it plus got a $30 factory rebate.

    Rick
     
  8. Rick Radford

    Rick Radford Supporting Actor

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  9. Kevin C Brown

    Kevin C Brown Producer

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    Great info!
    (I just joined the 20th century and got a burner myself.)
    Autosounds 2000 and Stryke are *good*, but what *I* really want are test tones every 1/20 ths of an octave from 20 to 160 Hz.
    Coolness... [​IMG]
     
  10. Sonnie Parker

    Sonnie Parker Second Unit

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