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1994-02-22
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Apparently-To: john.smith@gravis.com
GUS Programmer's Digest Tue, 22 Feb 94 4:26 Volume 9: Issue 13
Today's Topics:
GUS Programmer's Digest V9 #12 (2 msgs)
pitch of musical notes
which pitch?
Standard Info:
- Meta-info about the GUS can be found at the end of the Digest.
- Before you ask a question, please READ THE FAQ.
----------------------------------------------------------------------
Date: Mon, 21 Feb 1994 12:59:09 -0500 (EST)
From: Phat H Tran <ptran@sciborg.uwaterloo.ca>
Subject: Re: GUS Programmer's Digest V9 #12
On Mon, 21 Feb -1, GUS Programmer's Server wrote:
> Date: 21 Feb 94 11:03:00 MET
> From: "VISX80::GRECNER" <GRECNER%VISX80.decnet@musx53.zfe.siemens.de>
> Subject: GUS D/A converter
>
> Does anyone know how many bits does GUS's A/D converter use ?
> For the full 32 16-bit voices it needs 21 bits in fact. Since it's
> only 14 voices in the best quality, it still needs at least 20 bits.
The GUS uses a 16-bit DAC.
> I know that in proffesional devices (synths) they normally use
> 24-bit internal signal processing and 18-bit output A/D converters.
> So, how is it with GUS ? Does it utilize 16 bit ADC only ? How is
> then polyphonie implemented ? I'm asking because i find my new GUS
> not dynamic enough (when compared to Ensoniq EPS-16 +, for example,
> which is a proffesional 16 bit sampler with 20 voices ).
The GUS' MIDI drivers put a cap on how loud the samples get played.
For example, the percussions don't play loudly enough for my tastes.
The GF1 is capable of much greater dynamic range than the MIDI
drivers allow. Good MODs (especially those that use 16-bit samples,
like tek2.ult) played on a good player (such as Metal) have much
better dynamic range.
Phat.
------------------------------
Date: Mon, 21 Feb 1994 11:33:01 -0700 (MST)
From: "Shawn T. Rutledge" <rutledge@enuxsa.eas.asu.edu>
Subject: Re: GUS Programmer's Digest V9 #12
> From: "VISX80::GRECNER" <GRECNER%VISX80.decnet@musx53.zfe.siemens.de>
> Subject: GUS D/A converter
>
> Does anyone know how many bits does GUS's A/D converter use ?
> For the full 32 16-bit voices it needs 21 bits in fact. Since it's
Why do you think this is the case? It doesn't seem to me that it would
have to be. The GUS's onboard processor could mix the voices together
in software and then divide by a number that reduces the largest value
that occurs to a 16-bit number. You would not lose any headroom
that way; I mean you would, but the sum still has 16-bit resolution,
which is most of our range of hearing, and the card can still be
advertised as a 16-bit synth.
> only 14 voices in the best quality, it still needs at least 20 bits.
> I know that in proffesional devices (synths) they normally use
> 24-bit internal signal processing and 18-bit output A/D converters.
By doing what I just explained perhaps?
> So, how is it with GUS ? Does it utilize 16 bit ADC only ? How is
> then polyphonie implemented ? I'm asking because i find my new GUS
> not dynamic enough (when compared to Ensoniq EPS-16 +, for example,
> which is a proffesional 16 bit sampler with 20 voices ).
> Thanks for comments.
--
_______ KB7PWD
(_ | |_) shawn.rutledge@asu.edu
__) | | \__________________________________________________________________
* GUS * sci fi * Internet * ham radio * C * techno * packet * anti-Macintosh *
------------------------------
Date: Mon, 21 Feb 94 13:11:00 CST
From: eason@ncrnd3.StPaul.NCR.COM (Dale Eason)
Subject: Re: pitch of musical notes
Shawn T. Rutledge wrote that A is 400 hz and that middle C is 256 hz.
That is incorrect.
The A above middle C is 440 hz each adjacent note is called a half step.
Assending half steps are found by multplying the current note by the 12th root of
2 (approximately 1.059) and decending steps are found by dividing the current note
by the 12th root of 2.
This gives the what is called equal temperment tuning.
I think middle C is midi note 60. That makes the A midi note number 69.
Dale Eason
------------------------------
Date: Tue, 22 Feb 94 14:55:22 EST
From: stephen@csis.dit.csiro.au (Stephen Barrass)
Subject: which pitch?
..More about pitches and fundamental frequencies
freq+halfstep = freq * 2^(1/12)
This equation given in a previous post is correct but will cause significant
round-off errors if used recursively.
An alternative is to use a note number to freq conversion as follows
freq = rootF * 2 ^ (notenumber/12)
where rootF is the frequency of the 0th note.
Since we are using midi this is midi note 0 = C0 = 8.175Hz
(based on C5 = middle C = 261.6 Hz : reference from "Keyboard" March 1993 pp 56)
Table 2: Summary of MIDI Note Numbers for Different Octaves
(adapted from "MIDI by the Numbers" by D. Valenti - Electronic Musician 2/88)
Octave|| Note Numbers
# ||
|| C | C# | D | D# | E | F | F# | G | G# | A | A# | B
-----------------------------------------------------------------------------
0 || 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11
1 || 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23
2 || 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35
3 || 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47
4 || 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59
5 || 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71
6 || 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83
7 || 84 | 85 | 86 | 87 | 88 | 89 | 90 | 91 | 92 | 93 | 94 | 95
8 || 96 | 97 | 98 | 99 | 100 | 101 | 102 | 103 | 104 | 105 | 106 | 107
9 || 108 | 109 | 110 | 111 | 112 | 113 | 114 | 115 | 116 | 117 | 118 | 119
10 || 120 | 121 | 122 | 123 | 124 | 125 | 126 | 127 |
Using the equation and the table above the following table of root
frequencies was calculated for each MIDI note
C0 to G10 in Hz
---------------
8.175 8.6614 9.1764 9.7217 10.300 10.912 11.561 12.249 12.977 13.749 14.566 15.432
16.350 17.323 18.353 19.443 20.599 21.824 23.122 24.497 25.954
27.497 29.132 30.864
32.700 34.646 36.706 38.887 41.199 43.648 46.244 48.994 51.908
54.995 58.265 61.728
65.400 69.291 73.412 77.774 82.397 87.296 92.489 97.989 103.82
109.99 116.53 123.46
130.80 138.58 146.82 155.55 164.79 174.59 184.98 195.98 207.63
219.98 233.06 246.91
261.60 277.17 293.65 311.09 329.59 349.18 369.95 391.96 415.26
439.96 466.12 493.82
523.20 554.33 587.29 622.19 659.18 698.37 739.91 783.91 830.53
879.92 932.24 987.64
1046.4 1108.7 1174.6 1244.4 1318.4 1396.7 1479.8 1567.8 1661.1
1759.8 1864.5 1975.3
2092.8 2217.3 2349.2 2488.8 2636.7 2793.5 2959.6 3135.6 3322.1
3519.7 3729.0 3950.6
4185.6 4434.6 4698.3 4977.5 5273.4 5586.9 5919.3 6271.3 6644.2
7039.3 7457.9 7901.2
8371.2 8869.3 9396.7 9955.0 10547. 11174. 11839. 12543.
#@%#%^!
Internet : stephen@csis.dit.csiro.au #Q!^&%#$@!^&$#&
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------------------------------
End of GUS Programmer's Digest V9 #13
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