Connecting a condenser capsule to the grid of a tube amplifier, in order to build a tube mic. In this part we consider how to connect a capsule with two diaphragms in order to get a multi-pattern mic. First let`s examine the different pickup patterns available. There are three extremes: Omni, where the microphone hears sounds equally in all directions. Cardioid (heart shaped*), where sensitivity is greatest in the
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direction in which the microphone is pointing, falling off to a null point behind. And Figure-of-Eight, with equal (but opposite) pickup in front and behind, and null pickup to the sides. To complicate things further, the pickup pattern may depend upon the frequency, and some mics will have good directionality at higher frequencies, but become less directional as the frequency drops. But what if we want a microphone with selectable pattern This can be achieved by arranging a pair of cardioid capsules back-to-back, and combining there signals in different ways. We`ll call these capsules front and back, although of course they could be pointing in any direction. If we require a cardioid signal, we just take the front capsule and for omnidirectional pickup, we mix both signals equally. If we want figure of eight, we subtract the output of the rear from the front: where the signals overlap at the sides of the microphone, they cancel each other out producing null points. Other patterns such as hyper-cardioid and super-cardioid may be considered as in-between positions of these extremes. So, what is the best way to achieve this practically in our hypothetical tube microphone Two of the earliest commercial mics with more than one pattern were the Neumann U47, which offered cardioid and omni, and the U48, with cardioid & fig. 8. Let`s look at the U47, as this is probably the simplest way to combine the two capsules. In the U47 the...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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