Phone Conversation Recorder Issues

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Recording time and methods
One feature found in many phone call recorder models is the ability to record for a length of time exceeding that of the tape used.Most small units utilize cassettes as the recording medium.

At "normal" speed the amount of recording time on one side of any cassette is going to be between 1/2 an hour to a full hour.At "slower recording speed", a unit allows for many hoursof recording time.The longer the tape is,the thinner it will be physically.

Issues relating to thin tapes and slower speed recording
Thin tapes tend to jam and/or brake more easily in low end recorders than do their thicker (shorter) counterparts.They are also subject to "bleed through",a phenomenon in which the magnetic field from one side of the tape affects the recorded image on the other side,especially when stored for a length of time.

Tape that has bled through is very difficult to listen to as it has the "echo"of the other audio image surimposed on the original material.

The simplest solution to limited recording times is to slow the recording speed of the phone call recorder down to a fraction of its rated speed.Many telephone recorder do this but not with the same quality and results.

Let's consider the trade-offs of slowing the recording
The first one being that has tape speed decreases fidelity drops off sharply.With each subsequent speed reduction the same audio must be captured on significantlyless tape.And as the tape speed drops,certain frequencies also "falls off".

Many lower priced phone call recorder models slow the tapes speed simply by increasing the size of the capstan "doughnut" and, in fact, i've actually seen some examples where a rubber band was glued around the wheel,or electrician's tape wrapped around it.

All of these solutions are unaceptable,uneven wear on the doctoreddoughnut will soon cause major variations in the tape speed to the point whereit may become impossible to play back a tape recorded earlier on the same machine.Such cheap approaches do nothing to compensate for the various audiodeficiencies that also crop up.

The units also should incorporate a frequency compensation circuit that will over accentuate the high frequencies when recording.Some top line phone call recorder units also increase the strength of the bias signal in orderto saturate the tape.

Under most circumstances i do not advise the purchase of any unitthat does not meet these criteria.

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