1. Basic requirements for modern high-fidelity speakers
The fundamental requirement for modern speaker cabinets is to reproduce natural and accurate sounds, including: large dynamic high sound pressure level output, wide and smooth playback frequency range, harmonic distortion, amplitude intermodulation distortion and small frequency intermodulation distortion, pointing Sexuality is broad and reasonable.
2. Why is there no single-diaphragm full-range speaker that can meet all the above requirements?
Quite simply, if you want to reproduce a good low frequency, theoretically the volume of air exchanged per second is large, that is, the volume velocity m3/s is high, which requires a very large effective radiation area or stroke, but meets this requirement. The vibrating system has a very high vibration quality, so that such a loudspeaker constitutes an acoustic bandpass filter system with a very low pass-off frequency and cannot reproduce the high frequency domain. As another example, if a high frequency is to be reproduced, a vibration system having a very low vibration quality is required, which constitutes a complete high-pass acoustic filter with the magnetic circuit drive system, but it cannot reproduce low frequencies. There is currently no full-range speaker that spans the entire audible band and has excellent sound quality. The so-called full-range speakers on the market are usually wide-band midrange speakers, so the multi-way crossover speaker system is inevitable.
The multi-way crossover speaker system divides the audible frequency band into two segments, three segments or even more segments, and uses low, medium and high speakers specially designed for each frequency band, and combines them together. Multi-way crossover speaker system.
The multi-way crossover speaker system can easily meet the requirements of a high-fidelity speaker system, and has the following advantages:
1. When the audio input signal is multi-channel divided, the intermodulation distortion is small, and the modulation distortion in the sound field is easily reduced.
2. Accurate adjustment of system frequency/phase characteristics through a crossover network.
But it also has the following disadvantages:
1. Each frequency band is combined with speakers to make the adjustment of frequency response and impedance characteristics complicated.
2. Many components and high prices.
3. Composition of multi-channel crossover speaker system
First of all, there are many factors to consider in the division of the frequency band. In order to make the sound power response of the speaker system straight, not only the output sound pressure frequency characteristic on the axis should be straight, but also the directivity must be uniform. In addition, frequency intermodulation distortion (FIM) is generated when the overlapping low frequency and high audio signals are simultaneously reproduced. The greater the speed of the mode, and the greater the frequency ratio of the two signals being reproduced, the greater the distortion. In order to reduce the FIM distortion, the speaker should be used in a relatively narrow frequency band, that is, increase the number of sub-bands and make the bandwidth ratio equal; this is actually one of the reasons why the three-way is better than the two-way, and the two-way sound The result is better than a single channel speaker.
Since the audible band 20 Hz-20 kHz has about ten octaves, it needs to be divided into at least 2-4 bands. The size and structure of the speaker's vibration area defines the optimal frequency band, so at least 2-4 speakers with different vibration area sizes are required to cover the entire audible frequency band.
4, multi-channel crossover speaker system combination of speakers in each frequency band
Since each speaker unit has a different tone, the most important issue to consider when constructing a multi-way speaker system is to make the characteristics of each speaker to be harmonious, the tone is uniform, and the sounds are harmonious with each other. In addition, the continuity of the system directivity, the balance of the distortion components (odd/even harmonic distortion ratio), and the transient characteristics are considered.
5. Crossover network that combines speakers by multi-way frequency division
The frequency bands in which the speakers in each frequency band of the multi-way crossover speaker system can work well are allocated and combined by the frequency division network. Therefore, the frequency division network has a great effect, and the final fine adjustment of the sound pressure frequency characteristics, phase characteristics, and impedance characteristics is performed in the frequency division network. The crossover network basically consists of high/low pass filters. The components used in the crossover network have a large effect on the sound quality due to the loss and distortion of the inductor or capacitor. The network components used in high-fidelity speakers must be carefully chosen. For example, the frequency division network has low capacitance loss, high withstand voltage and current capacity, and the electrical properties such as capacitance, loss and electrical adhesion characteristics must be stable, non-inductive, and small in error, and the DC resistance of the inductor coil for the frequency division network. Must be small.
Therefore, the multi-way crossover speaker system is the basic configuration of the current high-fidelity audio system, and the three-way ratio is increased by two. If properly designed, it will mean better playback frequency band, distortion and dynamic range.
Because of the size limitation, small bookshelf speakers usually use two-way crossover speaker system. HiVi is one of the few audio companies in the world that successfully introduced the three-way speaker system into the bookshelf speaker design. HiVi M3A active wireless Wi-Fi bookshelf speaker design concept: the pursuit of greater sound dynamics, lower distortion and smoother wide frequency response.
A flange can also be a plate or ring to form a rim at the end of a pipe when fastened to the pipe. A blind flange is a plate for covering or closing the end of a pipe. A flange joint is a connection of pipes, where the connecting pieces have flanges by which the parts are bolted together.
Although the word flange generally refers to the actual raised rim or lip of a fitting, many flanged plumbing fittings are themselves known as 'flanges':
There are many different flange standards to be found worldwide. To allow easy functionality and interchangeability, these are designed to have standardised dimensions. Common world standards include ASA/ASME (USA), PN/DIN (European), BS10 (British/Australian), and JIS/KS (Japanese/Korean). In the USA, ANSI stopped publishing B16.5 in 1996, and the standard is ASME B16.5
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