Seekers Sky Soundlab Voice Spectra Analog Vocoder *Ultra Rare*

The Voice Spectra is a genuinely rare Japanese analog vocoder, built around:

• 12 analysis filters
• 12 corresponding synthesis filters
• Microphone and line-level speech inputs
• External carrier/instrument input
• Internal sawtooth carrier oscillator
• Internal white-noise generator
• Compressor
• Voiced/unvoiced detector
• Speech-tracking oscillator
• Dry/effect balance
• LED speech and excitation metering

The filter bank covers approximately 90 Hz to 8.9 kHz, divided into these bands:

90–130, 130–190, 190–280, 280–410, 410–610, 610–900, 900–1340, 1340–1950, 1950–2800, 2800–4100, 4100–6070 and 6070–8900 Hz.

What makes it special

Its chief attraction is unusually intelligible speech for a 12-band analog design.

The syllable function introduces noise for sibilants such as “S,” “SH” and “T.” Conventional filter-bank vocoders often lose these consonants because a pitched carrier contains insufficient high-frequency noise. Voice Spectra detects that material and supplies noise, substantially improving articulation. It can also create useful rhythmic effects when fed drums or percussion.

The other unusual feature is Speech Tracking Function, apparently a pitch-to-control-voltage circuit that extracts the voice’s fundamental frequency and drives the internal oscillator. Instead of holding a fixed robot-note, the carrier can follow the speaker’s vocal inflection. Tracking can reportedly operate at the detected pitch or shifted down by an octave or two.

Those features place it closer conceptually to more elaborate EMS/Sennheiser-era studio vocoders than to inexpensive keyboard vocoders

Sound and practical value

Expect:

• Clearer consonants than many inexpensive vintage vocoders
• A distinctly analog, filter-bank character
• Expressive monophonic robot voices through pitch tracking
• Good drum and rhythmic-envelope effects
• Less spectral detail than a 20-, 22- or 32-band vocoder
• No MIDI, presets, digital control or modern recall

It is primarily interesting because of its personality and rarity, not because it is objectively the most transparent vocoder available.

This unit is in excellent working condition, set up for 120V, all the filter bands work and are balanced.