Miscellanies

A collection of very short articles on music stuff.


Decibels in Recording Music

Electrical voltages are nominally referenced to the audio world using 1 Volt {RMS} as 0 dBV. Using this reference, we can use a signal's voltage to measure how loud that signal is.

Line levels

  • +4 dBV [1.228 V] = Pro / Studio equipment.

  • -10 dBV [0.316 V] = Consumer equipment; sometimes labelled as Aux, Tape or Phono.

Instrument range of levels :

  • -20 dB : Typical Keyboard would be -10dB to -20dB

  • -35 dB : Typical Electric Guitar would be -20dB to -35dB

Microphone range of levels

  • -40 dB

  • -60 dB

DI boxes and Attenuators:-

Line to Mic level would need appx. -50dB attenuation (from -10dB to -60dB).

Electric Guitar to Mic level would need appx. -40dB attenuation (from -20dB to -60dB).

From the Boss KM-60 Mixer manual, Input switch : Keyboards -20dB, Guitar -35dB and Mic -50dB
Use a DI (direct injection/ insertion) Box to attenuate your Instrument signal to go into a Mic Input [source- WikiCommons].

Impedance

Coming soon


FM Synth 4-Op Algorithms

The Chart shows the Algorithms for 4-Operator FM synthesizers. This applies to the following synths:-

  • Yamaha DX9

  • Yamaha DX21, DX27 & DX100

  • Yamaha TX81Z & DX11


The same Algorithms have the Operators numbered in reverse order (ie Op#1 has Feedback loop) for the following FM synths:-

  • Yamaha CX5M with YRM-102

  • Yamaha FB-01

  • Elka EK44, EK44M & ER33

4-Operator Algorithms for FM Synthesizers. Chart by Yala Abdullah.

Yamaha DX Synths : Inharmonic Table for Consumer Series Synths

Yamaha's Consumer DX synths use an Inharmonic Table for the pitch Frequency of the Operators. This Inharmonic Table applies to DX21, D27, DX100, TX81Z, DX11, CX5M and FB-01 synths.

The Frequency Ratios of the Inharmonic Table is as follows:-

0.5 1 2 3 4 5 6 7 8 9 10 11 12 13 14 150.71 1.41 2.82 4.24 5.65 7.07 8.48 9.89 11.30 12.72 14.13 15.55 16.96 18.37 19.78 21.200.78 1.57 3.14 4.71 6.28 7.85 9.42 10.99 12.56 14.10 15.70 17.27 18.84 20.41 21.98 23.550.87 1.73 3.46 5.19 6.92 8.65 10.38 12.11 13.84 15.57 17.30 19.03 20.76 22.49 24.22 25.95

Row#1 is based on integers (harmonic); Row#2 is based on square-root of 2; Row#4 is based on square root of 3; and, Row#3 is an average of Row#2 & Row#3. The non-integer rows are rounded to 2 decimal places only.

Yamaha's Pro DX synths use a percentage system for the pitch Frequency of the Operators.

TakTech DXi