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 15:57:16 07/16/01 (11)
- Re: About 4-Ohms for 40 ft loop of 30 AWG - Kurt Strain 18:54:23 07/16/01 (10)
- Re: About 4-Ohms for 40 ft loop of 30 AWG - wgeiger 16:43:19 07/17/01 (9)
- Okay. - Kurt Strain 21:16:47 07/17/01 (8)
- Re: Okay. - Kurt Strain 21:22:29 07/17/01 (7)
- Re: Okay. - wgeiger 07:31:45 07/18/01 (6)
- Romy's Revenge - Ron C 00:15:45 07/19/01 (3)
- Re: Romy's Revenge - wgeiger 18:08:21 07/19/01 (2)
- Re: Romy's Revenge - Ron C 05:37:26 07/20/01 (1)
- Romy's Rantings: You had your shot! You missed! - wgeiger 09:23:06 07/20/01 (0)
- Re: Okay. - Kurt Strain 23:08:03 07/18/01 (1)
- Resistor wire - Ron C 01:32:47 07/19/01 (0)