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Topic: The noise floor in sample recordings

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  1. #1

    The noise floor in sample recordings

    In general, I am against signal processing of samples to \"improve\" sounds. However, there is one kind of signal processing that I am all for--removing ambient room noise and electronic low frequency noise from underneath the frequency of each unity note on each and every sample. Since very few if any commercial CD makers bother to do this with their samples, it is still a do-it-yourself proposition.

    I specified removing the noise from underneath the frequency of the unity pitch. Removing the noise from above the frequency of the unity pitch will inevitably remove some of the overtone series of partials in each note, and change the instrument\'s tone--therefore, it should be avoided. Moreover, one should not remove the noise from below the unity pitches in samples of instruments that produce sympathetic vibrations at other frequencies--such as the piano with the pedal down, the zither, the harp, the acoutic guitar, etc.

    Why lower the noise floor? (1) The noise floor on various instruments playing simultaneously is additive and cumulative. If your samples have noise and you play a piece with many instruments, the noise is going to become an audible problem. (2) If you use a MIDI sequencer to program a crescendo on a bar of music or even on a single sustained note, not only will the volume of the note increase in GigaStudio\'s output; the volume of the noise in the recorded samples will also increase. You will begin to hear surges of noise in crescendos.

    Does anyone else out there lower the noise floor of samples in GIGs? What programs (or hardware) do you use to accomplish the task? How good are the results?

    Regards,
    Alkan

  2. #2

    Re: The noise floor in sample recordings

    <BLOCKQUOTE><font size=\"1\" face=\"Verdana, Arial\">quote:</font><HR>Originally posted by Charles-Valentin Alkan:
    In general, I am against signal processing of samples to \"improve\" sounds. However, there is one kind of signal processing that I am all for--removing ambient room noise and electronic low frequency noise from underneath the frequency of each unity note on each and every sample. Since very few if any commercial CD makers bother to do this with their samples, it is still a do-it-yourself proposition.

    I specified removing the noise from underneath the frequency of the unity pitch. Removing the noise from above the frequency of the unity pitch will inevitably remove some of the overtone series of partials in each note, and change the instrument\'s tone--therefore, it should be avoided. Moreover, one should not remove the noise from below the unity pitches in samples of instruments that produce sympathetic vibrations at other frequencies--such as the piano with the pedal down, the zither, the harp, the acoutic guitar, etc.

    Why lower the noise floor? (1) The noise floor on various instruments playing simultaneously is additive and cumulative. If your samples have noise and you play a piece with many instruments, the noise is going to become an audible problem. (2) If you use a MIDI sequencer to program a crescendo on a bar of music or even on a single sustained note, not only will the volume of the note increase in GigaStudio\'s output; the volume of the noise in the recorded samples will also increase. You will begin to hear surges of noise in crescendos.

    Does anyone else out there lower the noise floor of samples in GIGs? What programs (or hardware) do you use to accomplish the task? How good are the results?

    Regards,
    Alkan
    <HR></BLOCKQUOTE>


  3. #3

    Re: The noise floor in sample recordings

    I agree! There is, in most, commercial sound libraries, a good deal of noise. The challenge they face is in capture softer sounds. Signal to noise ratio becomes a factor. I did find that processing all of the .WAV files
    trough Ray Gun Noise Reduction helped a great deal.

  4. #4

    Re: The noise floor in sample recordings

    Hello Alkan,

    Xsample does this work in general, but in a little different way. Somtimes there are very important noise components of the instrument below the unity note. The thing is you have to divide into the \"right\" and \"wrong\" noise.
    We developed and programmed special tools only for this work.
    More than this: Our sounds are all \"as wave\" normalized and optimized for using all bits. You even can\'t here any \"wrong noise\" on any of our more than 20000 samples in our library.
    The table is easy to generate:

    Frequ = 8.175799 * 2^(\"Midinumber\"/12)

    Georg - Xsample


  5. #5

    Re: The noise floor in sample recordings


    Indeed, the background ambient noise floor, and how to deal with it,
    becomes a significant issue for very soft sound layers.
    This is one reason I am somewhat reluctant to use the ppp strike layer
    samples from the pianos that I recorded.
    The actual ppp layer note strike volume is down about 60dB or more from the FFF layer, and under normal circumstances the background noise is not audible. However, the ambient noise can be heard if the ppp samples are cranked up to max volume. Normally, this would not occur, but I can envision a few oddball uses where it could happen.
    Denoising seems the only practical approach, and if done carefully can
    be done without affecting the tone character of the sample. Nevertheless, I don\'t like the idea of processing the samples any more than is absolutely necessary.

    I have attributed the bulk of this problem to the fact that I have previously recorded the pianos on location.
    I am considering whether or not to record another piano, and was thinking of having it moved to an anechoic/soundproofed recording studio in the hopes that I could gain an extra 20 or 30 dB of improvement in background/ambient noise reduction.

    I would be very interested in the experiences of other sample makers who have used soundproofed recording studios for instrument sample recording versus recording on location in a concert hall or other location environment. Specifically, from your experience, is the improvement in background/ambient noise level in a studio significant enough to justify the expense of moving a grand piano into and out-of a studio (not to mention studio rental time). If I can\'t realistically expect to get 20dB or better improvement in the ambient noise, I may just forget the idea and record on location again.

    I don\'t want to get into the discussion of capturing the natural ambience of the hall along with the samples. Although that is an important part of the consideration, I believe it to be a separate issue from the achievable noise floor.


    Regards,
    Warren Trachtman
    http://www.wstco.com/pianosounds/



  6. #6

    Re: The noise floor in sample recordings

    <BLOCKQUOTE><font size=\"1\" face=\"Verdana, Arial\">quote:</font><HR>Originally posted by Francis Belardino:
    I agree! There is, in most, commercial sound libraries, a good deal of noise. The challenge they face is in capture softer sounds. Signal to noise ratio becomes a factor. I did find that processing all of the .WAV files
    trough Ray Gun Noise Reduction helped a great deal.
    <HR></BLOCKQUOTE>

    Glad to know I am not alone on this issue.

    BTW, I\'m not familiar with Ray Gun NR. IS it Mac or Windows? Do you have a URL for this program.

    One thing that would make lowering the noise floor easier to do: a table of unity pitches and their exact equivalents in Hz, for all MIDI notes. Does anyone have one?

    Regards,
    Alkan


  7. #7

    Re: The noise floor in sample recordings

    http://www.arboretum.com - Windows and Mac.

    We use this plug mainly for restoration and mastering at the studio but it does wonders
    on some of the(no way around it)noiseeee samples.

    Glad to know I am not alone on this issue.

    BTW, I\'m not familiar with Ray Gun NR. IS it Mac or Windows? Do you have a URL for this program.

    One thing that would make lowering the noise floor easier to do: a table of unity pitches and their exact equivalents in Hz, for all MIDI notes. Does anyone have one?

    Regards,
    Alkan

    [/QUOTE]


  8. #8

    Re: The noise floor in sample recordings

    Hello Alkan,

    I\'m sorry about conception details, because the conception is primary part of the Xsample company.
    The frequences below the unity note are not only interesting for piano sounds.
    All sounds except syntetics have harmonic components and noise components. The \"harmonic\" components below unity note (there are no \"harmonics\" but components with no noise character) I most time would agree to kill them (for example resonance sounds from strings or any disturbing sound). But the frequence regions of the noise components (for example air components of wood winds or percussional components of a stroke) have nothing to do with the unity note. For example a flute sound with unity note c6 has harmonic components of about 1000 Hz and more, but also very important noise components from maybe 200 Hz and more.

    Georg

  9. #9

    Re: The noise floor in sample recordings

    [QUOTE]Originally posted by WTrachtman:
    [B]

    I am considering whether or not to record another piano, and was thinking of having it moved to an anechoic/soundproofed recording studio in the hopes that I could gain an extra 20 or 30 dB of improvement in background/ambient noise reduction. [B]

    Very interesting replies from Georg & Warren. Evidently, with this thread, I hit on a substantial problem in the making of samples.

    Warren: IMO, recording a piano in an anechoic studio is a very bad idea, destined to failure. Having been involved in a number of professional recordings of classical piano music, it is my observation that the single most important factor in capturing an excellent piano sound, perhaps even more important than the actual sonority of the piano itself, is finding a recording locale with natural sounding acoustics--with a modest amount of natural reverb, not too much; a small hall with some natural brilliance at the top end; and no tubby-ness at the low end. Finding such locales demands patient search. There are not many.

    The absolutely worst places to record an instrument like the piano are anechoic recording studios that were designed for Rock. They were designed to absord sound. They have no natural reverb--since Rock musicians seem to be oblivious to all the poor quality artificial reverb and obvious signal processing their recordings undergo in post-production. You might be able to get a few extra dB of signal at the expense of the tone of the instrument! However, I must admit that if you record ONLY PPP piano samples in an anechoic studio, then natural acoustics become of lesser importance.

    Georg: I would be interested in reading more technical details about how you remove noise from your samples with hardware and software. Also, I am somewhat skeptical about your comment about musical vibrations below the unity pitch. Perhaps, in the cases of instruments with sympathetic vibrations--such as the piano with the pedal down, etc.--there might be some energy below the frequency of the unity pitch. But as far as I know, the concept of musical undertones produced by 1 vibrating string or by 1 column of vibrating air has been long discredited by the acousticians.

    Regards,
    Alkan

    [This message has been edited by Charles-Valentin Alkan (edited 01-22-2001).]

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