10-20-2021, 04:23 PM
(10-17-2021, 09:22 AM)Vacuum a écrit : C'est moche on dirait une enceinte de sono.
Haha, bon, l'esthétique, c'est selon les goûts de chacun.
Sur le caractère "enceinte de sono", c'est p-ê le look qui fait ça, mais ce ne sont pas du tout des enceintes de sono. Le choix des 15" par exemple, est bien décrit sur le site du concepteur de ce design, en privilégiant l'agilité de la membrane à ses "muscles". Ca dit ceci, au sujet du woofer:
"In regards to woofers and midwoofers we are looking for a driver that has low mechanical losses, low moving mass and a low resonance frequency. Low mechanical losses are important when playing music at low sound levels. If the losses are too high you get a speaker that doesn't "open up" unless it is played loudly. Then there is a low moving mass to take into account. I have found that a relatively low moving mass contributes to good articulation in the midrange - vital for a high quality two-way loudspeaker. There is no need for thick, heavy cones here - we are not building a subwoofer! And of course a low resonance frequency is essential for decent bass reproduction. For the Calpamos I wanted to use drivers from Faital Pro of Italy, they make good drivers at a very reasonable price. Looking at their portfolio and selecting the total of eleven 15-inch woofers I first did the most easy selection by setting the resonance frequency to a maximum of 35Hz. That left me with three woofers to choose from, namely the 15PR400, the 15FH500 and the 15FH510.
The 15FH500 and 15FH510 both have a relatively high moving mass Mms of 104 and 108 grammes respectively. The Mms of the 15PR400 is only 85,2 grammes. The 500 series woofers do have stronger magnets (higher BL) and stiffer suspension (lower Cms) to compensate for the higher moving mass but I am looking for am agile sports car here, not a heavy muscle car. Think Donkervoort D8 instead of Dodge Challenger (no offense to any muscle car owners). If you calculate the acceleration factor of the three midwoofers (divide BL by Mms) then the 15PR400 has the best acceleration factor even though it has the "weakest" magnet of the three.
One way of checking if a driver has low mechnical losses is to look at the impedance peak at the resonance frequency. If it is low and wide then the driver has high mechanical losses, if it shows a high and narrow, sharp spike, then we are looking at a woofer with low mechanical losses. All three of these Faital Pro 15-inch midwoofers have a 3-inch voice coil with an Re of 5,1 ohms but when we look at the impedance peak at free air resonance Fs, we see that both the 15FH500 and 15FH510 are peaking at around 87 ohms where as the 15PR400 has a nice sharp impedance peak of about double that value at 170 ohms. To me an impedance curve says more than a thousand words ;-) So the 15PR400 it will be.
The Faital Pro 15PR400 midwoofer has an impregnated, light-weight paper cone that is driven by a 3-inch / 77mm voice coil. The voice coil former is made from glass fibre resulting in low losses inside the magnetic field. This is essential when maintaining detail at low SPL's. Further high-lights are a light-weight neodymium magnet, low moving mass and low voice coil inductance. All these parameters are important when looking for high quality, smooth and expressive midrange. And last but not least a low resonance frequency of 35Hz in combination with a Qts of 0,32 are ideal for good bass response in a not too large cabinet."
Voir ici pour l'original, avec encore bien plus d'explications.
Un cocktail de RPis, de Boxem et de NAD, de Kefs, de Monitor Audio et de DIY, sur 6 zones d'écoute (à voir ici).