The best way to pick a speaker is with your eyes open.
All speakers are not alike.
Even speakers that appear similar can sound very different.
For example, when you compare a BIC VENTURI speaker system with others, you'll be astonished at how much more sound it delivers... even from a modest amplifier.
Behind the speaker grille you'll see the Venturi name over a cabinet slot that looks like a bass reflex "port" but isn't. "Bass reflex" speakers, whether they use slots, holes, or shelves, merely resonate an enclosure to a single frequency, achieving bass emphasis only at that one point.
.
The opening you see on a BIC VENTURI cabinet is the terminus of the Venturi path inside the enclosure (U.S. Pat. 3892288). It works as an acoustic transformer to produce bass energy as much as 140 times greater than would otherwise be achievable from a woofer alone in the same size cabinet.
A--Shows output of low frequency driver when driven at a freq. of 22 Hz. Sound pressure reading. 90 dB. Note poor wave form.
B--Output of BIC VENTURI coupled duct. (under the same conditions as Fig. A) Sound pressure reading 111.5 dB (140 times more output than Fig. A) Note non-distorted appearance.
Oscilloscope photos reveal that a BIC VENTURI speaker actually eliminates harmonic distortion from reproduced tones, literally purifying the sound and resulting in clean, tight and extended reproduction. That you can hear! Notice the square-shaped mouth of the exclusive BICONEX midrange horn (pat. pend.). This unit is exceptionally efficient. It has remarkably smooth, uncolored response because of its unique conical/exponential flare. It is made of an inert substance to avoid "ringing" and spurious resonances. But, equally important, it provides wide-angle dispersal of sound in both horizontal and vertical planes, making speaker positioning non critical. There is a super tweeter that operates in only the last octave for accurate musical timbre.
Even the control panel on the front of the baffle board is a surprise. It controls an exclusive built-in device (pat. pend.) which compensates for the normal loss in hearing of bass and treble tones, (figure C) at various listening levels. Regardless of amplifier loudness settings, you hear all the music, all the time. This is accomplished automatically with the switch in the "on" position, or, you can adjust tonal balance manually for the type of music you play or the kind of sound you prefer.
There's really much more to BIC VENTURI speakers such as how they com pare with other design types in performance, and the way they function in a high fidelity system.
. 
If you want to read some interesting and informative literature, ask your franchised BIC VENTURI dealer for a copy of our new 20-page consumer guide to loudspeaker performance, or write to us: BIC VENTURI, Westbury, N.Y. 11590. Div. of Fig. C.
-----------
(High Fidelity, 1976)
Also see:
HOW SPEAKERS WORK--All speakers make sound, but some make it differently than others.