Tuesday 15 January 2013

Sony / Coral 103a "Holey Basket"

As children, my brother and I were given my father's old Sony TC-630 reel to reel which we enjoyed immensely, spending many hours recording ourselves and digging through old stacks of tape. Eventually the motor died (i'm told it was replaced more than once prior to our using it) and the reel to reel was forgotten. At some point, while moving between houses the device was slated for the garbage bin but (thankfully) not before I pulled off the speaker cabinets. ...12 years later, I discovered that they contain the 16 ohm version of the 4" Coral "Holey Basket  / F103a" full range drivers.

Not the nicest looking flange...

When these photos were taken, the original speaker wire with 1/4" TRS plugs was still attached.
Sony 211-12 16ohm 5W
I mounted the speakers in an open baffle roughly 16" x 24" and let them run with some acoustic guitar music, and they definitely showed off the mid-range smoothness I have read about. I took a quick measurement to get an idea of what I was actually hearing.
Frequency response with smoothing (N=12)
Other than the dip at 1.5K, it looks OK (ignore everything below 300hz, room influence). For those that may be interested, I have some T/S numbers from DATS. Please take with a grain of salt...
SPL = 91.3 dB/W
R(e) = 14.8 ohm
F(s) = 114 Hz
Q(ts) = 0.809
Q(es) = 0.934
Q(ms) = 6.059
L(e) = 0.543 mH
V(as) = 5.47 L

Now the real question is what should I do with them? Two way with a sealed vintage 10" crossed at 400-500hz? Open baffle above an H frame woofer section? ...and do I really want a super tweeter to get some meaningful response above 10k?