4Ω or 8Ω speakers are a myth.
Just look at the impedance curves on Stereophile. Some go from 2 to 20 and beyond.
SPL efficiency @ 1w or 2.83v is also highly suspect as few speakers are 8Ω @ 1kHz.
Thermal Distortion your loudspeaker most likely suffers from it. But do you care?
Thermal Distortion is much more serious than just a maximum power handling limitation or side effect.TD is overlooked by most manufacturers as there is no easy (low cost) solution and TD is audible and measurable most of the time at most power levels. TD is caused by the conductive metal (aluminum, copper, or silver) voice coil getting hotter when you pass electrical energy through it. The more power you pass through it the hotter the metal gets. The hotter the metal gets the more the electrical resistance increase. The efficiency goes down and you need to ram in more and more power for smaller and smaller increases in SPL. It can be the reason you get fatigued while listening. If you are running massive power you are creating more TD in your transducers. But do you care? And is it a reason some prefer horn-loaded designs or SET-powered systems since they have the least problems with TD?
Showing 12 responses by ieales
Link that works LS_Heat_Dissipation-Thermal_Compression It also affects the XO frequency. See ieLogical the fly... The argument for high efficiency is specious as they have light coils with thin wire, which heats faster with less current. And lighter diaphragms and weaker surrounds which give rise to other issues. And lousy bass from ported boxes... As is the cable nonsense. The effect is so low as to be next to immeasurable. Planars suffer almost not at all. Ditto 'stats. The crossover issue is solved by using active XO, DSP and an amplifier per driver instead of stone age copper coils and foil and goo. Professional audio has been doing this for nearly 100 years! |
It's a question of balancing speakers and amplifiers. If speakers are 86dB/2.83v/1m, then you better have at least 200wpc and preferably 400w good, clean undistorted power @ speaker minimum impedance. Professional studios may have 1000wpc driving horn multiway speakers, usually without power eating passive XO. Sadly, too many today have zero understanding of basic fundamentals and buy faceplates.
|
provided one has the space to accommodate the system. Many a good big system has been utterly compromised in a space too small or with another failing where a smaller less efficient system would shine. For ½ century, I've been telling people the room is part of the system and it's possible to buy the best of and end up with unlistenable!
|
I'll wager that just replacing the caps would astound you. Nothing fancy, just polypropylene for electrolytics and Mylars [<<--- N A S T Y]. Erse and Dayton are plenty good. Solder any and all push on connections. I know because I BTDT for decades... 😎 If your speakers come from the likes of Spica, buy a couple of extra of each cap and match* as closely as possible to stock films. 40 year electrolytics are going to have an ESR that's likely off the charts. * Requires a capacitance meter or a pal with one. |