Jeg synes nogen for det til at fremstår som om det næsten er helt umuligt at høre hi-fi med alle disse skræklige refleksioner og løsningen er bare at fjerne dem, så måske er det er på tide at se på det grundlæggende i hvordan vores hjerne bearbejder disse og har gjort dette igennem millioner af år således at vi har kunnet overleve.
Jeg har taget forklaringen fra denne side
The Physical Principles of Sound - JISC Digital Media .
Her er det illustreret ved at der springes en ballon, det afgørende er at selve lydkilden ikke forvrænges sker det ikke så skal vores hjerne nok finde ud af resten.
Oversætte vi det til hi-fi så er det altafgørende som sagt at signalet er i orden når det forlader højtalerene, plus at højtalerene er stillet op således sidevægge, bagvægge osv ødelægge den direkte lyd mindst muligt , kort sagt højtaleropstillingen er vigtig og skal være i orden plus ens lytte postion skal være den optimale for stereo.
Som sagt tidligere kan man med fordel fjerne de første generende refleksioner og opnår en bedre klarhed i lydbilledet med en dead end / live end , men kan anlægget ikke spille uden en dead end / live end så er der noget galt med det output som forlader højtalerne, og problemet kan ligge i både højtaler og i resten af anlægget , ja reelt helt tilbage tiil optagelsen.
Er signalet i orden vil vi som mennesker ikke have nogen som helst problemer med at finde ud lydbilledet, og dette er ikke kun teori det er også min egen praktiske erfaring at det som giver problemer og ikke mindst rumproplemmer er i langt de fleste tilfælde fejlagtig gengivelse fra selve stereoanlægget, og en af de mest udbredte enkeltkilder til fejlagtig gengivelse er basrefleks . :
Sound in enclosed spaces
So far, the concept of wave propagation has been discussed without the consideration of boundaries. As mentioned at the beginning of this document, sound can be altered by its immediate environment and any further physical mediums it passes through after initial excitation. In order to understand this better, let us consider an example of how sound propagates in an enclosed space.
At one end of an empty room a balloon is popped which is heard by a listener at the opposite end of the room. There are three key aspects to how the sound behaves which explain how it is perceived by the listener.
1. After the excitation of the bang, the listener hears the direct sound after a short delay. This sound will have travelled the shortest distance possible from the source to the listener and contains the highest intensity.
2. Shortly after the arrival of the direct sound, waves that have been reflected (bounced) off one or more surfaces will be heard. These are known as early reflections, and would vary in the same room depending on the positions of the source and the listener. Early reflections provide information to listener that is used to perceive the size of the space and the location of the source. If reflections are long, i.e. have further to travel, they are perceived as an echo effect. They are separate from the direct sound and as such can add changes to the timbre of the overall sound.
3. Finally, after the early reflections have arrived, sound from many other reflection paths in all directions reach the listener.
As there are so many possible paths the effect is of a dense build up of reflections, which smears the overall sound together. This effect is called reverberation and is a coveted feature in music sound as it adds depth and space to sound.
The time taken for reverberation to occur is relative to the size of the room as a smaller room has a shorter distance for all the reflections to travel. This time between the direct sound and the reverberation is commonly known as pre-delay, the delay prior to reverberation.
Sound Intensity is lost on each impact of reflection and subsequently the reverberation decays over a duration known as the reverberation time.
