The ears wide shut high fidelity test

Date is after 2000 and we know that while electronic negative feedback (invented while on a ferry boat trip) is one of the greatest discoveries in electronics, benefits are not as promising on audio music amplifiers. (See for example transient intermodulation distortion, TIM, Mati Otala).


But this post in on anything that makes reproduction depart from the goal of same impression from the brain of producer to the brain of listener.


Other example on degrading quality is enclosures. We know a small recording studio [Gilford] can sound and will sound much worse to a bigger one. A WC will sound even more boomy. And a tiny WC like room like a speaker enclosure might sound horror of horrors inside it. A drive unit membrane is transparent to most sound and the ugliness will creap out.


A speaker enclosure made of linoleum may suffer much less from this effect due to elastomer dissipation of energy ie bass mid absorption etc. This test reveals some coloration on the linoleum Pleiades Auratone 5C speaker although it may not be objectionable.


Yet there is possibly nothing that can compete the obvious. An open baffle will do exactly what the word says. The sound will be open.


And here is the very simple test performed.


If on a conventional speaker the tweeter is disconnected all that will be heard by the listener is a muddy sound with all sort of distortion artifacts. Perhaps the existence of a tweeter is a bit like covering the dust under the carpet.


But what if one shuts ears by fingers for a few seconds while listening to a great quality setup. When shutting our ears only bass frequency content passes through.


This was done while listening to Time - Alan Parsons on a baffle speaker driven by just one transistor in class A (electrons flowing all the time) and the sound was bassy but it stil sounded very nice without artifacts. No boominess, no ugly reasonamce etc.


Signal path, setup:


producer's brain - Time - Alan Parsons Project - Sony CD Walkman, line out bridged to mono - Pleiadss BD139, Vb=12V, Rbias=12KΩ - Zeiss Ikon type 31-06 12Ω baffle speaker on small reverberant room - ears wide open or wide shut - listener's brain


With ears wide open the sound is fantastic too. Just amazing quality treble comes in to join the clear deep defined quick bass and smooth uncolored midrange.


The above simple system is with no feedback. So even if it makes some mistakes they are not interated to infinity(?) by susesive corrections of room feeding back to speaker membrane, speaker membrane generating EMf, EMF going back to amp input to be compared with a signal which has already changed.


Music moves on.


So is mankind.


Reference:

Acoustics for Radio and Television Studios - Gilford - BBC