Charlie;

I like Charlie’s comments as they bring back memories of an interest of mine.



You will have to forgive me for having been an electronics engineer in my past life. Most of my career was spent at Ampex as a Metrology Engineer (Science of Measurement). Our audio division was one of the best in the world, which included Dolby and many others at one time or another. For those that do not know Ampex build the worlds first commercial audio tape recorder and invented television tape recording, instant replay and a number of other interesting things.

The biggest problem with reproduction of sound and its greatest limiting factor is the speaker.

Audio tape became the standard for the recording industry at one point as it has greater sound recording capabilities than a record. 15 ips (inches per second) was the speed that most commercial machines were used at to attain the highest quality recordings. These tapes were then used to master records. No record could compare with an audio tape such as recorded on Ampex 465 series master tape. Along came CD’s and now we have “synthetic sound”. Convenient but for some listeners they leave a bit to be desired. A good point about CD's is a lower noise level than tape or records are capable of.

Vacuum tube amplifiers are known for superior transient response (ability to respond to changes in frequency/sound) compared to semiconductor amplifiers. A well designed tube amplifier will sound superior to any semiconductor amplifier in subjective testing or in analysis with proper test and measurement equipment.

Analog refers to the ability to faithfully reproduce a sound or complex waveform, while digital recordings cannot make such a claim.

The way to test any sound system is to pass a square wave through it and observe the result on an oscilloscope. Any rounding of the square wave is an indication of lack of faithful frequency response (due to capacitance and inductance). Low frequency loss will be observed as a rounding of the leading edge of the square wave and high frequency loss will be observed as a rounding of the trailing edge.

My dealings with speaker systems goes back to the late 1960’s when I began designing reflex systems in 2.5 cubic foot cabinets that weighed about 50 pounds each. The sound from the Jensen speakers I used was excellent. Today the sound from Bose speaker cubes about two inches on all sides is unreal.

Tom