Thanks to mass communication, one piece of news can quickly spread on the Internet and the media. Moreover, the source of information is only one news agency, and the rest simply copy and distribute further, reproduce the news. On news sites, you can see links to other informational articles with the same information. This is the principle of reverberation or echo, only in the field of mass communication.
The meaning of reverb
This term is found in physics and is associated with the section of acoustics. This is the effect of recoil and reflection of the sound wave from any obstacles, and its return to the source. This is found in any natural acoustic environment - in a stadium, in a large hall, room, or even a studio. The listener perceives with his ears not only the source of sound, but also its reflection from surfaces.
Two types of reverberation are known in physics: natural and artificial, when amplification and modulation of additional sound waves are created using technology. The sound displayed by the walls gradually subsides after the sound source ceases to sound. People only hear an echo or reflection of sound of different amplitudes.
Artificial Reflector
A reverb is a special device that increases the force of return of sound waves from walls or artificially creates such an effect in places where there is no natural acoustics. In the 70s, a tape reverb was popular. By design, it was somewhat reminiscent of a tape recorder of those times, with coils.
When the sound began to play, the reverb read it with recording heads and transferred it to tape. Then, the reproducing heads read these sounds from the tape. The number of heads indicated how many times the reproduced sound will be repeated. Some models had up to ten such heads and even more. The acoustics timbre of each signal with each head became quieter, which created the effect of a fading echo.
The qualitative reverb effect was achieved by the speed of the tape (about 38 centimeters per second) and the minimum distance between the playback heads.
A reverb is not a copier of sound, it is an apparatus that can recreate the gamut of a fading sound. Although, even at that time, tape machines worked in two modes: they created an echo and clearly repeated the sounds.
Reverb Features
Here are the main characteristics of the reverb and the standards to which it must meet:
- Impulse response. If sound enters the input of the recording heads before its output, a short ripple occurs. This interval between pulses should not exceed 0.05 seconds, otherwise the listener will perceive the echo as separate repeating sounds one after another. This is a sound defect.
- Reverb Time. This is the time during which the sound voltage drops after the cessation of the main sound at the input. At the output, a small reverb reduces the sound power to 60 dB from the first sound. The voltage should decrease, as it happens in a natural acoustic environment. This effect can be adjusted independently by changing the reverberation time and sound power. The signal decay rate is adjusted, or the ratio between direct sound and echo changes.
- Gear ratio. The amplitude of the voltage of the incoming and outgoing sounds. In a large room, the amplitude peaks on the graph are arranged irregularly with an interval of up to 4 Hz and dips of 25 dB or more. Therefore, in order for the reverb vocals to be able to simulate the acoustic echo in a large room, the density and length of the frequency peaks must correspond to these indicators.
What are the systems
Reverbs have several action systems:
- Tape. The reproduced sound is recorded on the tape.
- Spring loaded. They are small in size, work on the principle of sound delay and mechanical spring vibrations.
- Digital reverb. The main sound is fed to the transceiver modulator, which delays the signal and creates an echo effect. Digital signal processing gives it a specific color.
It is worth paying attention to the spring system, since such a device is cheaper, the design is not complicated, and you can make such a reverb with your own hands.
The principle of operation of the spring apparatus
The signal entering the apparatus is amplified by a special device, the movable element is converted and oscillates. A spring is attached to this movable element, which, depending on the length and turns, determines how long the incoming signal reaches the receiver and how long the sound will be.
What standards should be followed?
Consider what parameters you need to consider when manufacturing a reverb at home.
So, the peak repetition rate in the band range of 100 Hz should be no less than 15 and no more than 20. The average interval between signals is 0.025 seconds. The operating frequency range is from 150 to 3000 Hz. Sound vibrating time at the lower frequencies - no more than 4 seconds, at the upper - no more than 2 seconds.
Increasing the echo time at lower frequencies distorts the clarity of the sound. In the spring reverb, the time at high frequencies is quite small, no more than 2 seconds, but the lower the frequency, the longer the time becomes, reaching 8 seconds. Therefore, we need to install a damper in our reverb, which will reduce the time of signals at low frequencies.
How to calculate spring length and turns
A spring is a mechanical filter that passes low-frequency sounds through itself. You can use steel wire or a piano string with a diameter of 0.2-0.4 millimeters. The winding is done on a lathe so that the turns are of the same diameter. The frequency of the delay line is 3-4 kHz, and the diameter is calculated by the formula: average wire diameter = required cutoff frequency is equal to the diameter of the winding. The number of turns depends on the delay time of the sound.
Converter and check calculations
Instead of a converter, you can use a magnetized rotor or a coil with a magnetic core. The coil is attached to the reverb wall with a piece of wire. Being between two magnets, the transducer vibrates the coil and spring under the influence of a sound wave. It is necessary that the wire passes through the converter. One of its ends inside the transducer catches the main wire using the hook method, and the other end, 30 millimeters long, is the holder. If a larger diameter wire is used, then the cross-section of the turns should proportionally correspond to the diameter of the wire itself, measured in cubic millimeters. The receiver at the other end performs the opposite action.
Not everyone can calculate and make everything exactly at home, because checking the delay time is performed by special equipment. Not everyone has it. But a little logic, ingenuity and quick wit, and a reverb - this is not just a dream.
In artisanal conditions, we set up the device like this: including a sound generator, we measure output data with a voltmeter. Slowly change the frequency of the generator until we determine the interval of peaks and dips in the frequencies.
Modern reverbs
Let's briefly discuss the best reverbs that are considered the best in the ranking today.
In the first place, the Bricasti Desing M7 is an excellent digital device of the highest quality. Former Lexicon engineers have teamed up to create the best in algorithmic sound reverb. Even despite its high cost, according to studio recording experts, it is much cheaper than similar high-end reverbs. Digital format - 24 bit / 192 kHz, on a dual-core DSP platform. Fully compliant with studio requests.
Second place goes to the Fender '63 Reverb. An exact copy of the legendary 1963 reverb. Fender developers have tried to completely recreate the device according to its parameters. Phenol electronic parts were replaced by printed circuit boards, 6K6 lamps were replaced by 6V6. First-class engineers have put into their creation all their many years of experience, so the device is in demand by many world musicians. Reverbs are also used to enhance the sound of musical instruments equipped with an acoustic output, such as electronic guitars.