An 8 USD purchase
from a local second-hand store reveals vintage
ScanSpeak drivers from the Seventies. Possibly
only of interest to the very few, but the D3804
drivers here were in absolute mint condition and
it would be interesting to see how they performed
compared to the modern ScanSpeak D3806/8200 used
in my SP38/13
construction. These no-name speakers were made in
the town of Horsens for the (former) Danish
EXPERT chain store. 21W-3804-P2A drivers in mint
condition, revealing diecast baskets, alnico
magnets and paper pulp cones with a coated paper
half-roll surround, actually cone and surround
moulded in one piece. Quite unusual and -
possibly not that easy to do.
With the small closed box used
here, we're into a no-deep-bass design, targeting
book-shelf placement and driven by the common
tuner-amp integrate of the Seventies, a
"radio". These speakers were made under
serious economic constraints and most noticeable
here by looking at crossover components, i.e.
tiny coils and electrolytic caps.
The mid and tweeter are basically driven in
parallel with different points of roll-off,
providing a decent flat response of upper
octaves. The bass driver doesn't even have a
low-pass filter, thus depends on its inherent
The bass driver cone is
made from long-fibre paper pulp, today only found
in the ScanSpeak 18W/8542-00 driver -
and not to forget, the JA8008. To my
ears, a cone material that can deliver excellent
midrange quality. The voice coil is wound on a 38
mm aluminium former ensuring good power handling
compared to coils wound on the usual paper former
of that time. The driver display a nice smooth
response only up to 800 Hz, from where a steadily
decline is seen. Why this is so is a hard to
tell, but the surround, a relatively weak magnet
and lack of dust cap may all play a role. Mms
should not necessarily count for an early
The Peerless mid features
a closed back made from rather resonant metal,
creating high Fs and a huge bump in response at
1200 Hz. It could possibly be used as tweeter
alone, reaching even higher that the D3804 dome.
Crossed at e.g. 3 kHz it might not do bad at all.
The D3804 domes are
quite sensitive displaying some 92-93 dB/2.8V/1m
and with a little creativeness, a two-way system
can be modelled with a decent flat response up to
16-18 kHz as can be seen below.
Is it worth while? If
you really fancy old drivers, yes. Make an e.g.
30 liter aperiodic cab, drivers driven from the
crossover seen below - and I'm sure you can have
some fun hours. As a replacement for modern
drivers? Forget it. We can get modern driver with
s much better response profile making crossover
construction much easier.