Deutscher Text: Die Firma Yamamoto produziert Elektronische Geräte, und Elektronische Bauelemente. Die Elektrogeräte unterliegen dem Elektro- und Elektronik-Gerätegesetz, wofür wir diese Marke nicht angemeldet haben. Wir haben für dieses irrsinnige Gesetz einfach kapituliert, wie vielen in der HiFi Branche. Bedanken Sie sich hier. Aus dem Grund liefern wir keine gebrauchsfertige Elektro Geräte nach Deutschand. Ausserhalb Deutschland liefern wir nur an Abnehmer wofür dieses Deutsche Gesetz ungültig ist. Nach Deutschland liefern wir nur die elektronische Bauelemente. Wir bitten um Ihr Verständnis.


Yamamoto Sound YS-500 High Efficiency Loudspeaker


The Yamamoto YS-500 have received the Audio Excellence Award 2010
from the Japanese HiFi Review magazine PHILE

Link here

Review on 6moons


This loudspeaker is based on combination of technologies. The bass speaker is one that can used with an open or closed cabinet. The high frequency speaker is a compression horn driver, which is the vintage technology for horn systems.

Mid + Highs

Mid + highs come from a wide band compression driver, which is fully linear starting at 1kHz, at 107dB. It must be said, that this is quite exceptional. The theory of a compression driver is interesting, and it differs from any normal speaker. Compression drivers have no paper cone, only the voice coil. A normal speaker consists of a voice coil (the moving part inside) and the cone, which moves the air. For the cone, the materials must be as light weighted as possible to reproduce high frequencies well. However if too light weighted, mid range frequencies can not be reproduced. So as a matter of principle, the cone with a normal wide bad speaker is a compromise, because it needs a minimum weight, and this weight limits the dynamic behavior, limits the efficiency, and gives distortion too.

So there has always be the search for "no mass" tweeters.

Is there a solution? YES there is! It is called: Compression driver.

Compression drivers were invented in 1924. In 1953 the phase plug was invented, making it possible to build very linear, distortion free compression drivers. These have inside only the voice coil, and no paper cone is attached to it. So almost no mass is connected. The word compression driver comes from the air inside the horn, getting compressed (only for high frequency signals). This high compression is interesting, it makes the voice coil moves very little only, only a fraction of a millimeter, and consequently will do so at high force, and very low distortion. With any sound source, the energy is either in form of high force, or large movement. Compression drivers have the principle of high force and small movement. So the voice coil movements are very small, and there is no cone attached to it. Only the voice coil moves the air inside a pipe that is attached to it. This pipe slowly changes it's shape from round to square, and once square, it is connected to the horn.

The horn's function is now to decompress the air, so to say adapt it to normal conditions as outside the horn. The energy at the beginning (deep inside the horn) consists of small movements with high force and small surface (25mm diameter). Then by means of acoustical transformation, at the end of the horn (the wide part) the movements are at low force, but high surface (19x 31cm). So the horn's surface is 19x31=589 cm² which is very much, and yet the moved mass of the voice coil and it's surface membrane is all there is.

This very low mass, is the reason of the exceptional dynamics of compression drivers.

The history if the Yamamoto compression driver horns goes back to 1986. This very beautiful Yamamoto horn of solid hard wood, as used in the YS-500 has been developed by Yamamoto in 1993 on special demand of speaker builders in Japan. The efficiency of the compression unit is given with 107dB/1m in the data sheet, though it must be said the horn as used here, reduces this value, down to 99dB. This is due to a wider radiation pattern, as chosen here for the horn. By this, the sound gets fully natural as if coming from a normal sound source. However the dynamic behavior of the compression horn driver stays unaffected. This makes the YS-500 sound excellent at low sound level, and yet l capable of higher loudness with no loss of dynamics at all.

Picture of compression driver inside

The woofer

Though from another company, the Bass loudspeaker seems like naturally fitting to the horn driver. Both work ideally at a cross over frequency od 1200Hz. This makes is possible to use both with a very minimized filter of only 6dB/Octave. It results in minimal energy loss in the filter, and yet the cross over frequency is clearly defined in a natural way, because the tweeter starts to be effective by itself, at the frequency where the woofer stops. (Though it should not be tried this way, the cross over between these two chassis takes place at 1200 Hz naturally even without filter. This is only to show how nicely these two together)


For those who want to change and work on the filter, it is open, and easy accessible. The coil for the woofer is universal and has three taps. I recommend to have a less bass output when the hearing room is very small, but this is very personal of course, and it is a general item and not directly related to the YS-500. However, what is important, if some day someone whishes to make a modification, it is very nice when the filter is easy accessible. For technical oriented buyers of the YS-500 I will give instructions with the speakers. (Filter circuit diagram here)


Specifications of Yamamoto YS-500: 

  • Enclosure: 21mm of Cherry Wood, Asada treated
  • Sensitivity: 98 dB/W/1m
  • Recommendation power amplifier output: 1Watt or more
  • Impedance: 8 ohms
  • Frequency characteristic: 35Hz - 18,000Hz
  • Outside dimension: 460(W) x996(H) x560 (D)
  • Weight: 38kg