Sampling Rate/Frequency, Conversion, and Signal Processing of MultiEffects

Discussion in 'Digital & Modeling Gear' started by Nhoj, May 26, 2018.

  1. Nhoj

    Nhoj Member

    Messages:
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    Joined:
    Nov 22, 2017
    Boss GT100/ME/MS3/GT1/GT10/GT8/GT6/GT5
    Sampling Frequency
    44.1 kHz
    AD Conversion
    24 bits + AF method
    * AF method (Adaptive Focus method) is a proprietary method from Roland & BOSS that vastly improves the signal-to-noise (SN) ratio of the AD and DA converters.
    DA Conversion
    24 bits
    Boss GT3
    Sampling Frequency
    44.1 kHz
    AD Conversion
    24-bit with 128x oversampling
    DA Conversion
    20-bit with 128x oversampling


    Boss GT1000
    Sampling Frequency
    96 kHz
    AD Conversion
    32 bits + AF method
    * AF method (Adaptive Focus method) is a proprietary method from Roland & BOSS that vastly improves the signal-to-noise (SN) ratio of the AD and DA converters.
    DA Conversion
    32 bits

    Zoom G.1ut/1/1x/1u/nu/2/3/3x/7/9

    Sampling frequency
    96 kHz
    A/D conversion
    24-bit, 64-times oversampling
    D/A conversion
    24-bit, 128-times oversampling
    Signal processing
    32-bit

    Zoom GFX8/GFX4/
    Sampling frequency
    40 kHz
    A/D converter
    20 bit, 64 times oversampling
    D/A converter
    20 bit, 128 times oversampling

    Zoom GFX3/GFX5/GFX707/606//707II
    Sampling Frequency
    31.25 kHz
    A/D Conversion
    20-bit, 64-times oversampling
    D/A Conversion
    20-bit, 8-times oversampling

    Zoom 505
    Sampling Frequency
    31.25 kHz
    Analog/digital conversion
    18 bit, 128 times oversampling
    Digital/analog conversion
    16 bit, linear


    Zoom Gn/On/MS/CDR/5/ Series
    Sampling frequency:
    44.1 kHz

    A/D conversion:
    24-bit with 128x oversampling

    D/A conversion:
    24-bit with 128x oversampling

    Signal processing:
    32-bit


    Headrush

    Sampling rate
    96 khz

    Line6 Helix/HD/POD

    Sampling rate
    48 khz
    16 bit
    (correct me if im wrong Frank ;) )

    Digitech RP/XP/IPB/GSP/GNX

    A/D/A Converter:
    24-bit high performance audio
    Sampling Frequency:
    44.1 kHz


    Mooer GE200

    Sampling rate
    44.1 kHz
    24 bit
     
    Last edited: May 26, 2018
  2. Nhoj

    Nhoj Member

    Messages:
    1,461
    Joined:
    Nov 22, 2017
    Vox Tonelab

    Sampling rate
    44.1 kHz
    24 bit
     
  3. phil_m

    phil_m Supporting Member

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    Jun 29, 2012
    Location:
    East of the Sun, West of the Moon
    If you’re talking about the actual converters, they’re 24-bit, 192kHz... Although, the highest sampling rate you can get out of the USB out is 96kHz.

    The internal sampling rate in the signal path is oversampled to much higher rates at different points.
     
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  4. aleclee

    aleclee TGP Tech Wrangler Staff Member

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    5868 ft above sea level
    IMO, sampling rates are kind of like power amp wattage ratings: once you get above a certain threshold, there are other factors that are going to make a bigger difference.
     
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  5. Nhoj

    Nhoj Member

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    Nov 22, 2017
    Thanks for the info, i dont know line6 hardware , because i dont own one yet, tried the Helix Native , and its awesome im pleasantly surprise!
     
  6. Nhoj

    Nhoj Member

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    Im really surprised about the 96 kHz sampling rate specs of the old Zoom G series , i still got my G2 that why it sound so good back from that days.
     
  7. Jay Mitchell

    Jay Mitchell Member

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    Oct 13, 2007
    This kind of speculation is largely misinformed. Two facts are relevant:

    1. System sampling frequency determines bandwidth. The absolute upper limit on bandwidth in a sampled-signal system is the Nyquist frequency, which is one half the sampling rate.

    2. Bit depth determines dynamic range (the difference between the noise floor and the strongest signal the system can produce), which affects signal to noise. The greater the bit depth, the lower the digital noise floor.

    When considering the sonic performance of guitar modelers, neither of the above two parameters is ever a limiting factor. The difference between 22.05kHz (44.1kHz SR) and 24kHz (48kHz SR) bandwidth is utterly irrelevant to guitar sounds. The smallest digital dynamic range is 96dB (16 bit). There's never been a guitar that has that much dynamic range, and any processing that introduces compression will reduce dynamic range (e.g., every amp sim) to well below the guitar's intrinsic capability.

    The greatest differences in sonic quality are due to modelers' outboard analog electronics, conversion devices (A/D and D/A), internal oversampling rate for nonlinear processes, and the quality of the processing algorithms. The information you need to identify such differences will never be provided by manufacturers. Some of it is proprietary, and none of it would be understood by the target market.
     
    Last edited: Jun 30, 2018
  8. Nhoj

    Nhoj Member

    Messages:
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    Thanks for the info youve shared! Maybe this is why some companies are not telling specifications and not including it on their manual.
     
  9. cliffc8488

    cliffc8488 Member

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    May 13, 2006
    To elaborate on Jay's statements.

    1. 44.1 or 48 KHz is more than adequate for not only guitar processors but ANY audio processor. 88.2 or 96 K makes for nice marketing but, in reality, performance can often decrease when running converters higher than necessary. This is due to activity at the converters digital I/O pins injecting noise into the converters themselves. Personally I wish the industry would adopt a 64 KHz sample rate standard but this is for esoteric reasons.

    2. The dynamic range of a guitar, UNDER IDEAL CONDITIONS (i.e. inside a Faraday cage) is not much greater than 100 dB. To capture this you would theoretically need 17 bits (17 bits gives about 102 dB). To allow sufficient "overhead" one should add a couple bits. 20 bits is plenty and yields about 120 dB of dynamic range. Anything greater than 20 bits is marketing. There isn't a converter made that gets much better than 100 - 120 dB dynamic range in the real world. You only need 20 bits for that. AKM has these new 32 bit converters (AKM557x). This is comical as they only have 112 dB of dynamic range so they give 19 bits of data and 13 bits of noise. Once you put a guitar in a real-world EMI environment that dynamic range drops precipitously (60 dB or even less).

    The ANALOG electronics before and after the converters is far more important. Knowing when to use JFET vs. bipolar op-amps, knowing how to select the right op-amp for the task, etc. far outweigh the sampling rate and advertised bit depth of a converter. Good quality components aren't cheap though.

    Internal oversampling determines aliasing performance in nonlinear processing. The higher the oversampling, the lower the aliasing but the more processing power required (= $$$$). Aliasing noise can easily dominate output dynamic range. So, again, sampling rate and bit depth are immaterial in comparison to the things that really matter.
     
  10. Briandress

    Briandress Member

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    So basically if we have an interface with converters on par with the Helix, and we are running Helix Native on a pc with enough spec to run the algorithm they would sound the same when monitored through the same monitor source?
     
  11. yeky83

    yeky83 Member

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    Yup. There's already a few demos online to demonstrate this.
     

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