First, why should antique speakers be derived from horn speakers? Because in the past electron tube era, the power of the power amplifier was generally insufficient, and the unit needed high enough sensitivity. The horn is an acoustic structure with high sensitivity and high efficiency. So antique speakers are basically horn speakers.
Second, regarding horn technology, JBL Professional/Synthesis can be said to be the only one that has survived since the horn broke ground and has always maintained its leading position.
Antique speakers are not clearly defined, but they usually refer to speakers before 1975. There is a proper term called vintage speakers.
Here I can point out straightforwardly that although horn technology is one of the oldest speaker technologies, horn technology has not been perfected in the true sense until the past decade. The standards for perfect horn technology are mainly in the following three aspects:
At the end of the 20th century and the beginning of the 21st century, the psychoacoustic experiments of Dr. Floyd Toole and Dr. Sean Olive provided guidelines for speaker design;
2. Advanced finite element simulation software such as Comsol multivariate physics simulation software has gradually been applied to the speaker field in recent years;
3. The truly ideal compression drive unit has only been invented in the past ten years.
In short, a good speaker needs to have good frequency response on both axial and off-axis, and ensure that the directivity coefficient is relatively constant and the absolute value is less than a certain value (for ASW that accurately restores the image, etc.)
For the second point, the explanation will be more complicated. To understand this, we must first understand the shortcomings and reasons of traditional horns. Traditional horns are divided into exponential type, logarithmic type and so on. And it is usually a single constant, that is, a simple function with a fixed constant.
From the first point mentioned above, the final speaker should be designed to have as constant directivity or specific directivity as possible. But generally, the directivity of the speaker unit is weak at low frequencies and strong at high frequencies. And the directivity will change with the frequency. If you want to control the directivity of each frequency band in a relatively ideal range at this time, it means that the horn itself needs to have different characteristics in different frequency bands.
More generally speaking, because the compression unit is not absolutely ideal, the horn should not be ideal either.
Different parts of the horn will affect different frequency bands, so if you want segmented control, then the design of the horn must be segmented, that is, there should be multiple constants.
Traditional horns often have the problem that the frequency response curve near the axial direction is not smooth due to high frequency diffraction. Translated into popular words, the high frequency is not delicate enough. This problem cannot be solved by multi-stage horns. A horn of one more dimension is needed, or even a horn of several more dimensions, and special treatment near the throat.
This is the reason why some new models of corners are designed to look strange.
For the third point. Some people think that the ideal horn speaker should be a two-way speaker. Therefore, a compression drive unit with sufficiently wide bandwidth and sufficiently low distortion is required. On the one hand, the horn speaker itself is equivalent to a bandpass filter. On the other hand, it is difficult to design a single compression drive unit to have a wider bandwidth. For example, a traditional 3~4 inch compression drive unit can reach about 700Hz in the dive, but the high frequency extension basically begins to attenuate severely at 12kHz. If a UHF is equipped at this time, the mid-high and the ultra-high are both traditional horns, then the sound effect will be further reduced due to factors such as extra crossovers near the ultra-high. If the compression unit is small, it can meet the high frequency extension, but the low frequency dive can only reach about 2kHz in many cases. It cannot be connected to a 15-inch loudspeaker. If a small speaker is used, it is difficult to control the directivity (including absolute value) in the vicinity. At the same time, the horn will increase distortion to a certain extent, so the distortion of the compression drive unit should be lower than that of the traditional unit.
The creatively designed D2 double ring diaphragm of the former Soviet Union Dr. Alex Voishvillo compresses the treble, while satisfying low-frequency dive, high-frequency extension and low distortion. This makes a relatively ideal compression drive unit possible.
In fact, if you roughly understand the above content, it is not difficult to see that the antique horn speakers have limitations of the times, or are far from good sound. . .
The Loews theater chain controlled by MGM operates 130 of the largest theaters in the United States. MGM is not satisfied with the speakers used in these theaters, most of which are the "Wide Range" system built by Western Electric.
These systems were introduced in 1933 and used a three-way design with low-frequency, mid-frequency, and high-frequency speakers. The midrange unit is a large curly "snail horn" driven by a compression driver. This is the legacy of the "Voice of Action" full-frequency system of Western Electric Corporation, which dates back to 1927. The Wide Range system adds a snail horn with cone-shaped woofer and horn tweeter mounted on a flat baffle. There is a 12-foot path length difference between the snail horn and the unit mounted on the baffle, which produces echoes when replaying transient sounds. These systems are also limited in their high volume and low distortion capabilities.
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That's right, some models of Western Electric in the United States that have been blown away are actually eliminated by Lansing Manufacturing 90 years ago.
The sound quality of speakers 100 years ago is still being advocated, which is a pure scam.