Listener’s Judgement of Audio Quality

2014 – November 28

For quality of audio transmission the listener’s judgement is considered the most valuable, and a listener is usually at the same time a consumer. Could it be wrong?

In author’s opinion an ideal transmission may only be called so, if listener hears ideally that what had came to the microphone during recording. Only in that way sound is exactly the reflection of it’s origin – an instrument or a performance.

How is the customer judging the symphony orchestra recording?

His best sound experience comes from his presence in concert hall where he is positioned 10 – 40 meters from all instruments. His worse from listening to bad audio set or big power and noisy stage/movie speakers and it’s not a subject of discussion

When sitting in front raw instruments differ in distance – those near by are heard mostly directly and those behind are partly reflected from walls and other instruments. Those near to listener are heard louder. Extreme of this differences is received by conductor of orchestra and although it’s not optimum for musician wishes, the reception is direct and detailed.

When sitting in back raw  instruments are damped by sitting in front audience and major role play reflections from walls. Person experiences it like distant sound but  is not aware of it – see below.. Receives almost equal loudness for all instruments and that  is good side. Which of this two positions is the right original sound which should be expected from speaker at home when listening to recording?

None of them! Because recording microphones were not placed in any of this positions.

 Microphones

Microphones can only be placed in direct distances to instruments – usually a number is placed between the musicians.Why? Because microphone does not posses ability of human ear. That ability it is learning of the surrounding acoustic where we stay. After hearing sense and other senses (like vision) knows the reflections and reverberation the brain rejects them from material and that is the reason why we hear sounds good even in reverberated surrounding.

With grow of bad acoustic the level of reflections may cover original sounds so for that reason we have to use acoustic treatment.

With microphone it is different story – it cannot reject anything. If positioned in audience much of of reverberations, reflections and public noises will be passed to our homes. It is simply not practiced , and cannot be practiced.

Anyone can record his voice or audio set sound at home at distance app. 3 meters to proof that  By comparing to what he is used to perceive primary  it’s easy to feel annoying. difference.

So we see now that what we memorized at concert from real performance is not what had been recorded at time. To know how it sounded for recording stuff, one should stay between musicians in few places in one time, just like mics of channels . Impossible!

Then after we tune the speakers to make impression we memorized as part of audience. We modify it’s timbre to regain …what is not in recording. To achieve it, it is necessary to upbeat frequency ranges which are responsible for reflections in recording – middle low range and then, to balance it with trebles, we need to upbeat them too. Then we prize spaciousness of sound which… isn’t in recorded material. And unfortunately also we fall in famous black hole of problems with hurting  trebles.

Ok, we gained our desired concert mode. But can such speaker recreate each solo instrument, each true voice, each different acoustic of performance or direct signal from instrument  pickup?

Author claims that it is not – part of direct reality had been removed, and our set will always have this deficiency. Such speaker will show bad sides for some kinds of music or recordings while for other will show beauty which may not be true. Have we heard already speaker like this? Author heard too many.

Author’s conclusion is that for judgement of audio only neutral sounds, which are from definition comparable to original, may be used. That is the pure noise, or sounds with minimum reflections – like good memorized outdoor sounds . It is possible only for perfect trained and experienced ear having good ability to memorize heard before timbre. Not for musicians, music lovers or self-proclaimed comparators of speakers. It  does not involve understanding of music.

Recordings may be intentionally modified by sound engineer to attach impression of audience but it is done  to only by him personally defined requirements. And that is even more confusing.

Using above indications and noise/outdoor method, author gained in normal not treated room right impression of instruments, in natural „like microphone” distance which corresponds to room dimensions. No annoying separation from them by artificial distance, and in final effect had got, impressive reality of all audio sounds at home.

Michal Czabajski