11
Speakers
The speaker is the final and most vital component in all sound reproduction. You should therefore
select speakers carefully. Some of the more important properties of a speaker are frequency
range, efficiency and sound power at low, medium and high frequencies.
Sound radiates from a speaker such that low frequencies propagate evenly in all directions. As the
frequency increases, the sound waves become more focused and high frequencies propagate in a
focused cone.
Tandberg speakers are sealed enclosure designs. A speaker has a has a self-resonant frequency,
just like any oscillating system. The self-resonant frequency determines the lower limit frequency
the speaker can reproduce. The lower the self-resonant frequency, the lower frequencies the
speaker can reproduce. In a sealed enclosure design, the self-resonant frequency increases as the
colume of the enclosure goes down. Conversely, the larger the enclosure, the lower frequencies
the speaker can reproduce.
The self-resonant frequency can also be lowered by increasing the mass of the membrane, which
means more power is required to move it, i.e., the speaker efficiency is reduced. In other words, a
speaker’s ability to reproduce low frequencies can be achieved
with a large speaker enclosure and
high efficiency (more sound power) or with a smaller enclosure and low efficiency. The integrated
speakers in Huldra 8-56 and Hi-Fi System 113/106-10 are designed according to the latter
principle. As the Huldra 8 has a power output of 2x10 Watt, you will still have more than sufficient
power for an ordinary sized living room.
One of several properties determining the sound power a speaker can produce, is the length of the
homogeneous magnetic field in which the voice coil moves. Again, bass reproduction is the limiting
factor. To maintain sound power at lower frequencies, the membrane excursions must increase. If
the voice coil moves out of the homogeneous field, harmonic distortion increases significantly.
By making the tweeter membrane small, the sound propagates in a larger cone.
