In Reply to: but how much is the series R anyway? posted by Joost Riphagen on July 16, 2001 at 10:08:45:
In a low impedance circuit, such as that for an amp/driver, a small change in resistance is significant. [Rg] for an audio amp is typically < 1 Ohm. A 40 ft loop (2-cond. 20 Ft. run) of 30 awg. wire = approx. 4 Ohms. Primarily what you are hearing is the significant change in system [Qt] that takes place when a "thin wire is used" Most driver/enclosure (horn) design assumes [Rg] = 0.1 Ohm. Note that for the driver alone [Qes] = (([Re]+[Rg])/[Bl]^2)*([Mms]/[Cms])^(1/2). If the system is over damped ([Qt] < 0.707), adding resistance may be beneficial, otherwise generally it is bad news. Typical driver [Re] ranges from 3 - 12 Ohms. The table below gives dc resistance for wire sizes most likely to be used in speaker/amp circuits.Regards,
WHG
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Follow Ups
- About 4-Ohms for 40 ft loop of 30 AWG - wgeiger 16:20:31 07/16/01 (0)