Yamamoto Sound Craft
38cm 2-way speaker system YS-500 1 unit

The YS-500 is a 2-way speaker system composed mainly of the Woodhorn SS-500. The speaker unit uses a 38cm diameter woofer and a 1-inch throat horn driver unit. Both units use neodymium magnets to achieve a highly efficient conversion efficiency of 98dB/W/1m with a powerful magnetic circuit. The main attraction of this sensitivity is that sufficient sound pressure can be obtained with a tube amplifier with an output of only 1-2W. In addition, the frequency response is 35 Hz to 18,000 Hz, the crossover frequency is 1,200 Hz, and the impedance is 8 Ω, making it easy to use in both tube amplifiers and transistor amplifiers. The Wood Horn SS-500 is a high-performance horn manufactured by laminating laminated cherry wood and carving it. The biggest feature is that it can obtain a very smooth frequency response.

Rear opening enclosure that inherits the goodness of a flat baffle

The enclosure of the YS-500 uses an open rear and bottom surface. The planar baffle method is characterized by a lively and responsive sound.
Based on the idea that the closed type and bass reflex type tend to have a muffled and crisp sound while maintaining a low frequency level, we have adopted such an open-rear enclosure so that it can be used in a relatively small footprint while taking advantage of the advantages of the flat baffle system. The YS-500 measures 460 mm on the left and right and 560 mm in depth, and is designed to achieve the same characteristics as the size of a flat baffle of 1m x 1m. Therefore, as a system, it is characterized by a clear sound with a moderate frequency response and a sense of dynamism. The enclosure is made of laminated cherry wood with good sound quality, and the connection part is reinforced with solid Asada cherry wood. Cherry wood has a good resonance that is also used for musical instruments, and you can get a beautiful sound that resonates with the heart.

The rear of the woofer unit is equipped with brass angles, and the legs are made of African ebony blocks.

6dB/oct scheme with excellent phase characteristics is used in the network.

The crossover network uses a 6dB/oct type with excellent phase characteristics. This is due to the fact that there is a natural connection between the units, and their phase characteristics are excellent. Components with excellent performance are selected to maximize their quality, and the network circuit consists of only three parts, including the attenuator part for level adjustment. The filter coil is a copper foil coil with a cut core with a capacity of 100 W, and the capacitor is a polypropylene capacitor made by Dearborn of the United States enclosed in an ebony case. The speaker terminals are large terminals machined from pure copper to ensure sound quality measures.

The woofer unit uses a brass angle for reinforcement in the magnetic circuit on the back. This reduces the effect of reaction on the driving part of the woofer unit and helps to improve the sound quality in the low range. The legs are made of African ebony, which lift the enclosure by about 25 mm and allow air to flow from the bottom to provide a natural sound spread.
The included aluminum perforated net does not absorb sound like a general saran net, so it has less impact on sound quality.

Model	Rear opening 38cm 2-way speaker system
Speaker unit	38cm woofer unit, 1-inch throat driver unit, SS-500 woodhorn
Enclosure Material	Asada Sakura laminated wood 21mm thick, urethane coating
Output sound pressure level	98dB/W/1m
Recommended Power Amplifier Output	1W or more (for tube amplifiers)
Crossover Frequency	1200Hz
impedance	8Ω
Frequency response	35Hz~18,000Hz
External dimensions	460(W)x996x(H)x560(D)mm
weight	38kg

It looks like a simple floor standing system, but in fact, it is a back-open type with a flat baffle folded without a rear baffle or bottom baffle. The unit uses a 38-diameter woofer and a 1-inch throat horn driver. Both are current varieties, with the driver being made in Italy and the woofer being made in the United States. Of course, the horn is made using the luxurious construction method of laminating and carving SS500 cherry laminated wood, Yamamoto Acoustic Crafts' own product. The cabinet is made of the same laminated wood, and the joints are reinforced with Asada cherry wood. There is no sound-absorbing material at all, but it is held down by a metal rod in the woofer magnetic circuit. The crossover network is a simple 6dB/oct type. A large cut-core inductor is used for low pass. The high-pass condenser is stored in an ebony case. It is a completely unique two-way system.

Since the total baffle area is about 1.5㎡, there should be no bass, but the fact is that the bandwidth balance is surprisingly well-formed. It is a likability system that is comfortable with a straight extrusion that has no place to turn. As a test, when I set the compensator of the Accuphase C2810 preamp to position 1, the open strings of the wood bass roared vigorously. The string bass of the orchestra is also moderately extended, and at 2 it is rather over. However, it is also true that it is a theater-type speaker that competes with the penetration power of the mid-range and the thickness of the line. If possible, I would like to team up with a tube amp to explore the labyrinth of sound, and it was a magical and unusual work.
*STEREO SOUND