| There are Several Choices:
1) Buy a "Mini Audio Amplifier" model # 277-1008 @ $11.99 from Radio
Shack and use its speaker (16 ohms, ~ 2 inch in Dia.).
2) An amplifier stage between the ISD
device and the 8 Ohm speaker.
3) Two 8 Ohm speakers in series.
4) A 8 ohm resistor in series with a 8 Ohm speaker.
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The ISD chip has very little power
for the speaker, therefore:
(A) The cheaper the speaker the better--cheap speakers have high compliance
(small magnet) which means they are loud for the input power at the expense
of fidelity (of which the ISD has little).
(B) The larger the diameter the speaker--within limits--the better.
(C) Always enclose the speaker: A speaker held in mid-air will sound
weak & tinny as compared to the same speaker inside, say, a Styrofoam
cup.
(D) Make sure the openings at the front of the enclosed speaker are
large: many holes or large holes or both.
(E) Experiment with various options--it will be very Instructive! |
External Amplifier.