‘Working-in’ a Speaker

To improve the bass response of an otherwise good loudspeaker, try softening up the edge suspension to permit greater and easier cone vibration. To do this, connect the voice coil in series with a 6.3 volt filament winding, using a current-limiting rheostat, as shown in the diagram. Any 6.3 volt filament winding will do, either as available in any convenient piece of radio apparatus, or using a separate filament transformer (as shown).
Place the speaker where a rather loud 60-cycle (50-cycle in Canada) buzz will not irritate you, and apply power, using the entire 100 ohms in series at first. Than gradually reduce the series resistor until the cone is vigorously vibrating at its maximum safe amplitude. (Use judgment here as it is possible to rip the cone out entirely). Allow it to vibrate thus for five to six hours. Now reconnect the speaker to your hi-fi amplifier. The improvement in bass reproduction will amaze you. -C.F. ROCKEY

This is just one of the many ways I have heard about in which some people ‘beat up’ their new speakers in an attempt to ‘soften them up’. What you are attempting to do is effectively soften the surround, to allow a greater excursion of the cone, thus yielding a ‘little more’ bass frequency response. The cone also plays a little less ‘stiffly’. The word ‘improvement’, as used in the article above, is really a subjective concept. There are a few other ways to soften up the surround, but I personally don’t like any of the tricks that I have read/heard about, so this information is presented just for your ‘education’. What you do with this knowledge is up to you, and not my responsibility. It may interest you to know that the 5 or 6 hours suggested ‘break in’ time worked out way too little for me. It took days before I heard a big difference, but I believe that this was because I was not letting the cone vibrate with quite enough ‘vigor’. The above method is ‘improved’ upon, and the voltage is applied in a very calculated manner, which can be seen on the Weber VST website. Uncle Spot has an online calculator to determine the safe voltage to apply to your speaker and still accomplish the goal of softening the surround. If you feel comfortable with a variable AC power supply, then check it out HERE. This may be what I was doing wrong, but I am still not a fan of the practice. Lastly, every old-timer I have met and spoken with remembers when Canada was on a 25Hz system (the power transformers had a huge core), but never a 50Hz system. We’ve been on a 60-Hz system since I’ve been around. (Radio-TV Experimenter/1959 Annual)

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