The owner's manual/operating instructions that I purchased was the original factory document and it was in at least three and maybe more languages. I no longer have it because I sold the tape recorder and included the owner's manual/operating instructions and a service/repair manual that I bought on ebay for the new owner.
Turns out this was not the manual i was looking for. The concertmate 670 keyboard i have is a "Realistic" model made for Radio Shack and none of the diagrams on the owners manual i received matches up. HOWEVER, I must say the service Owners Manual provides was fast and efficient by being available online. The manual was in good readable condition and easily downloaded.
Great price, Quick delivery, the document was very usefull A+++++++++++++++
Text excerpt from page 45 (click to view)
3. Set Cutoff to 200 Hz and Q to about 50. The range of notes covered by the current zone should sound muted.
To Change the Filter Cutoff Envelope:
1. Select page two by pressing the right cursor arrow.
VCF Tracking: Envelope Amt: +1.00 +0%
Investigate the effects of envelope control over the filtered sound by moving the cursor to the Envelope Amount. Use the data entry control to set a value of +40%. This allows the envelope to control the filter cutoff frequency. 2. Select page three by pressing the right cursor.
VCF Attack: 0.20s Hold: 0.00s Decay: 0.00s Sus:99% Rel:0.40s
Move the cursor under the Attack time on line one and vary the data entry control. With larger values, it will take more attack time for the filter frequency to go from lowest to highest cutoff frequency. Vary the various envelope parameters, and observe the effect these changes have on the sound. To check out inverted envelopes, set the envelope parameters as follows:
VCF Attack: 0.20s Hold: 0.00s Decay: 0.00s Sus:99% Rel:0.40s
Play and hold a chord. This is a non-inverting envelope in the sense that the envelope increases the filter cutoff frequency above the initial cutoff. To select an inverting envelope where the cutoff decreases below the initial cutoff, press the left cursor arrow.