Richard skrev:John Atkinsson har gjort omfattande mätningar med mjuka material kontra spikes under en högtalare. Han har också utfört ett stort blindtest med bl.a. konstruktörer från BBC där alla föredrog spikes under ett par spendor högtalare.
Här är ett väldigt omfattande test med mätningar av honom- betydligt mera omfattande än de man kan läsa på sonic designs hemsida.
Resultatet visar att det inte alltid är självklart vad som är bäst, tex. blev resultaten bättre med en stabil högtalarelåda som är extremt lätt och styv ( celestion 600 av aluminium ) än en tung låda ( wilson watt ) som är kraftigt stagad om vi talar resonanser som stör upplevelsen av ljudet.
Det finns flera överaskningar här, åt båda hållen:
http://www.stereophile.com/features/806/index.htmlCitat från länken:
It was the impecunious English, therefore, who first got into loudspeaker tweaks. In particular, they heavily investigated the relationship between the speaker and the stand, and the stand and the floor (though the Mod Squad's Steve McCormack pretty quickly got into the act with his effective Tiptoes, which in turn spawned a flood of imitators). I remember putting on a series of single-blind listening tests at the very first Heathrow Penta Show, where show visitors could audition a pair of Spendor loudspeakers either on stands that rested on the rug, or with the same stands spiked through the rug to the concrete floor below. The difference was not subtle; listeners overwhelmingly chose the spiked speaker stands as sounding superior. Even a couple of engineers from the BBC (an organization not normally regarded as being tweaky) confessed that they heard the spikes improving the sound of the Spendors.
The late Raymond Cooke of KEF, who was a subject in those 1982 listening tests, offered a typical dose of Yorkshire common sense by pointing out that when hi-fi got going in earnest in the 1950s, loudspeakers featured such massive construction as sand-filled cabinet walls. They also often sat directly on uncarpeted floors—the thought that they might not have a secure enough foundation wouldn't have crossed their owners' minds. Since that time, speakers have become flimsier and rugs thicker, allowing the cabinet to move in reaction to the woofer's motion.
This is a practical illustration of Newton's Third Law of Motion: to every action there is an equal but opposite reaction. If a typical 10" woofer cone/voice-coil assembly with a moving mass of 50 grams moves 25mm peak-peak, a cabinet with a mass of 5kg sitting on a friction-free surface will move 250µm: a quarter of a millimeter! Any friction from the support will reduce the cabinet motion, but even if it does by a factor of 100, the resultant 2.5µm cabinet motion is still of the order of that of the tweeter diaphragm's and will frequency-modulate its output. Spiking the speaker or its stand to the floor beneath the rug gives the system a much better mechanical "ground," reducing its reactive motion to the benefit of its sound.
It's been 10 years since those blind UK tests, yet here in the US there is still much skepticism. In the April 1991 issue of Stereo Review (p.62), Julian
Hirsch noted that he had "never found [spikes] to make the slightest difference in the sound of a speaker," while a year later, Stereo Review's high-end correspondent, Ian Masters, mentioned in passing that he doesn't feel "spiky feet" to fit his "high-end criteria" (footnote 3). There was also comment earlier this year from an otherwise knowledgeable subscriber to the computer bulletin board The Audiophile Network to the effect that he could not see why the stand should have any effect at all on the sound of a loudspeaker, let alone spiking that stand to the floor."
