[Hallicrafters] R-42 speaker design

[Craig Roberts]

The reason for the great sound of the R-42 is a combination of  easily 
exceeded expectations and the enclosure. The "Reproducer" is a simple -- 
and probably un-engineered -- bass reflex design.  It's a sealed box 
lined with sound dampening material with an opening or "port" under the 
front of the speaker.  The port is just a decoratively louvered slot, 
really.

As for the "sophisticated" frequency compensating network, it's a pair 
of .5 mfd paper caps whch are switched in and out of series with the 
speaker leads.  The speaker driver itself is an ordinary 8-inch 
permanent magnet dynamic mounted on a plywood board.

If you think the SX-42 and R-42 combo sounds great (which it does) , you 
should hear my $15 restored-from-basket-case Telefunken Gavotte 7 on 
shortwave and FM!

73,

Craig
W3CRR