Spec Corporation RSP-901EX Real-Sound Processor

Spec-Corp RSP-S1EX Real Sound Processor

The "TRUE RICHNESS OF MUSIC" to your ears

Once you listen to the PSP-901EX for the first you will quickly realise this is not 'just' an audio-accessory, but a real a piece of highly crafted audio engineering for improving the sound quality of your system dramatically. Effects of using the RSP 901EX can lead to a more clearer and natural throughout entire range with 901EX. In short you can experience more 'real sound' a superb sense of involving musicality. In a word, you will be convinced that 901EX brings out fully potential of your audio system!!

The operating principle of "Real-Sound Processor" had been made public on the Japanese specialized magazine named MJ, "AUDIO TECCHNOLOGY" by Mr. Yasui in 1971. He conceived this concept as "Impedance Correction" for speakers.

Yasui-san was a senior amateur researcher and a person of authority in semiconductor linearWe recognized the principle improving the dynamic characteristic of the system were directly related to amplifier and speaker impedance matching was an extremely important factor for getting superior sound quality from an audio system. Now, after more than 40 years passed, we regard his view point as an excellent insight and much further a relevant challenge for the present "audio-technology".

We recognized the principle improving the dynamic characteristic of the system were directly related to amplifier and speaker impedance matching was an extremely important factor for getting superior sound quality from an audio system.

Spec Corp have not reached a satisfactory conclusion on an effective method of measuring the fixed dynamic conduct and demonstrate a real connection between the characteristics and our hearing.

A speaker being a transducer, utilising some of it's electric energy by converting it into kinetic motion. Because the speaker (transducer) does not present a perfectly even load as seen by the amplifier, as music is a constantly changing impedance load therefore not an ideal situation to have. You can also consider it the speaker demanding a more current than the amplifier could realistically at certain level.

Also we should consider the, "Counter-electromotive Force" of speaker. The motion of speaker is started in the magnetic circuit or voice-coil of the unit the current supplied from amplifier. Taking Fleming's left-hand rule:- at the same time this motion raises up counter-electromotive force in the voice-coil by Fleming's right-hand rule. It is true your amplifier drives speaker, however the fact speaker has a direct effect on the amplifier loading by this counter-electromotive force.

The counter-electromotive current returns to the amp via the speaker cable, making it difficult to drive speaker in accordance with the input signal. This CEMF causes a negative effect especially when using traditional semiconductor linear amplifiers.

The transfer function of semiconductor amplifier is poor in linearity compared to tube counterpart; this type of amplifier inevitably needs to correct these static characteristics by using a type of negative feedback circuitry.

However the use of negative feedback designs leaves the amplifier stage vulnerable to this (CEMF) counteraction causing complicated phase delays inside of amplifying stage. Needless to say, this physical phenomenon degrades the sound quality of the audio system in the amplifier / speaker components.

Spec "Real-Sound Processor" has two major functions; one is designed to improve and reduce the fluctuations of the speaker's impedance frequency characteristic. The other is to absorb the counter-electromotive current from speaker including networks composed of inductors. Accordingly, the processor allows the amplifier to drive the speakers more faithfully to the sound source, thus demonstrating improved sound resolution and possible amplifier start-up issues. Other properties which can also improve are the natural timbres and texture. Summing up you could be presented with deeper, richer and more realistic tonal sound you have never experienced before whilst giving your amplifier an easier life!

It has taken SPEC a long time to settle on the exact components for the latest RSP 901EX real sound processor by individually pursuing many numbers of passive components through strict listening tests and measurment of each of the resistors, capacitors. But fortunately early 2014, we met up with the outstanding quality parts supplier. In our opinion it was one of the highest quality and state-of-art hermetic seal oil-filled capacitor we have ever heard, named "Green Cactus" made in USA, by Arizona Capacitors, Inc.

Spec also pays particular attention to the 901EX's box,produced by famous 'Shirakawa Co., Ltd' at Hida-Takayama, beautiful historic town. You will see also woodworking is the Japanese traditional handicrafts. Also this goes to make the Spec RSP 901EX a must have component for any quality qaudio system.

SPEC CORP RSP-901Ex Specifications


  • Package contents: 2 units, 1 polishing cloth, manual
  • Compatible speaker impedance: idealy 10 Ohms or lower
  • Max amplifier output: < 1Kw
  • Size:100 mm (width) x 47 mm (height) x 117 mm (depth)
  • Weight: 0.2 kg each
  • The effects will differ depending on your speaker system and the amplifier used with it.
Spec-Corp RSP-S1EX Real Sound Processor Spec-Corp RSP-S1EX Real Sound Processor Spec-Corp RSP-S1EX Real Sound Processor Spec-Corp RSP-S1EX Real Sound Processor Spec-Corp RSP-S1EX Real Sound Processor Spec-Corp RSP-S1EX Real Sound Processor