Sonark a écrit:heresie a écrit:Le facteur d amortissement est de 800 ce qui est favorable pour les bass.
Pour la énième fois :
Slew factor is measured by driving an amplifier to its rated output at 1000Hz and increasing the frequency (at a constant input level) until the waveform shows 1% distortion. The ratio of that frequency to 20kHz is the slew factor. Any number greater than 1 effectively guarantees negligible slewing distortion in hi-fi listening. In my experience, over hundreds of amplifier tests, the slew factor is rarely less than 4 or 5 and is usually greater than 25.
There is another specification, rarely found these days outside the world of high-end audio, that is, and always has been, of little or no practical significance to the user. I refer to damping factor, the ratio of 8 ohms (a standard loudspeaker impedance rating) to the internal source impedance of the amplifier. The effect of a low impedance (typically a small fraction of an ohm) is to damp, or surpress, certain resonances in a speaker, especially low-frequency cone resonance.
There is no question that damping is desireable, but there is a catch. The damping resistance includes not only the source impedance of the amplifier but also the resistance of the connecting speaker cables, the speaker's crossover inductor(s), and the voice coil. So if the amplifier's source impedance is 0.01-ohm, the cable resistance is 0.1-ohm, and the speaker's internal resistance is 4 ohms (a typical value), the damping factor is not 800, or even 80, but a mere 2. Spending extra money for an amplifier with a 0.001-ohm impedance, or a cable the size of a garden hose with a 0.01-ohm resistance, will not have the slightest effect on a speaker's damping.
The myth that extremely high damping factors are beneficial has been with us for many decades, and it was as nonsensical forty years ago, when I first became active in high fidelity, as it is today. Most such fads fades away with time, and almost all respond well to a dose of common sense. In the meantime, they are good for a chuckle or two.
Julian Hirsch - article intitulé "Obsolete Specifications" publié en 1992 par l'AES
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T inquiete pas j avais bien lus ton post
Ta reference n est pas abolue et en remet en cause d autre
En acoustique y a un peu de tout et chacun a ses theorie, j essaye de piocher la ou elle me paraisse le plus fiable, mes references sont pour l instant linkwitz et vance dickason qui preconise de la mesuré et d en tenir compte, c est pas pour rien.
Par contre pour te rendre utile tu pourrais m aider a connaitre quels sont les facteur ideaux pour une bonne tenue du grave (mise a part gros condo et compagnie), pourquoi les amplis en classe D qui ont souvent un fort facteur d amortissement sont reputés pour mieux tenir les hp que leurs homologues de classe AB , le tout avec politesse sinon c est pas la peine Mr Sonark
Par ailleurs j ai l intuition que des module zapulse ponté ou pas (800W/8ohm) avec leur alim on un meilleur rapport qualité prix que tes ampli, puisque que tu t amuses a descendre tous ce qui leur fait concurence