If the signal from an electric bass guitar is listened to in an electronic chain with flat frequency response the result in non flat frequency responce to our brain. It sounds bass heavy, and this low heaviness covers the mid and high frequency content.
The reason could be:
The design of a particular electric bass.
Fletcher Munson equal loudness curves. Ie the louder the acoustic intensity (acoustic energy measured in milliWatts or Watts) the more sensitive our ear brain becomes to low and high frequencies.
The above is the same reason a flat microphone can sound bass heavy when the voice is reproduced at high intensity.
The same principle of connecting a Pleiades filter (which is just an inductor) in parallel with the output of a mic to compensate for heavy perceived bass can be applied to electric bass too.
A Pleiades filter can be connected at the output of the electric guitar pickup.
The inductance of the connected inductor or coil adjusts how much low cut or high pass is done.
If a relative small inductor is made and connected, its magnetic core may saturate at high levels and this causes the inductance to drop. By usinng this creatively a compressor can be made too. The louder we play the more bass is cut aiding the end result to sound flat to the listener's brain.
Kind to our ears too, speakers and possibly instantly making an electric bass sound as a finished product.
It is softer, the bass is not boomy. Mid and high frequency string detail shines.
A DI transformer can be made by using this principle. Less inductance ie more bass cut is achieved by less number of turns wound for making the transformer.
If using Magnetec Nanoperm ring cores the number of turns needed is further reduced making the construction much more easy to make. As an example we may like to aim for an inductance of 6 Henries
The output of the bass guitar pickup and Pleiade filter combination can be connected to a 1 stage electron tube battery powered preamplifier. An example is the Pleiades V4 preamplifier operating the EF183 electron tube at just 3.6 volt. This is done by a 3.9 Megohm resistor from anode to grid to free the electrons. The amazing electron tube sound with dynamics in its overload characteristic is achieved easily with just a few components. Schematics are freely available on the euroelectron posts.
Also a Pleiades power amplifier can be connected using just one transistor or electron tube operating in class A, (electrons flowing all the time). Suitable speakers can be the Pleiades speakers containing many speakers in series parallel combination, all mounted on a panel. They are therefor dipoles giving very deep bass and no box coloration.
Pleiades concepts and schematics are open source.
Set up, signal path:
Yamaha RAX200 bass signal taken direct from pickup - Pleiades filter - JVC Nivico 9425W 70's radio
In general inductor filers sound better to capacitor ones. If one looks at the top quality EQs to make the commercial recordings sound correct to listener's brain, such as Pultec, EMI RS106A, Neumann mastering EQs etc, there are full of inductors. Each inductor, capacitor combination is used for a particular frequency. The Pleides filters in general use only an inductor making a gentle slope and very musical sound. It is a 1st order (described by a differential equation of fist order) 6dB per octave filter. For a variable filter responce a variable resistor potentiometer can be connected in series to the inductor and the combination in parallel with the electric bass pickup. Of course the resistance of the wire of the inductor plays a similar role too changing the slope. It is a joy to play bass on a radio whole listening to music on another radio.
No comments:
Post a Comment