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impedance altering damping factor

Started by -DJ-, Jul 17 2004 06:43 PM

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4 replies to this topic

#1 -DJ-

500 - 1500w RMS

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Posted 17 July 2004 - 06:43 PM

howdies people. was having a chat with a guy today at work who reckons he's a bit of an expert (he actually isnt too bad...) but i got thinking (allllways a dangerous thing).

is there a certain rule or formula to calculate the changes in damping factor into lower impedances? what areas of the amp's design are most influential on this spec? how does it differ between the different amp toplologies and various classes?

i got curious because this guy has an oldschool class a/b (i'm guessing) 2chan rodek and he reckons damping factor into 4R stereo is >400 yet 120 when bridged into the same load. i was under the impression that damping factor would half when you half the impedance!?!? or does efficiency (or another variable) come into play?

is this guy smoking crack? perhaps some of you more elctro-whizzically insightful people can shed some light on the matter.

cheers

d

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#2 tuneman

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Posted 18 July 2004 - 12:11 PM

i did the maths once but carnt remember now! but damping factor is very over rated, when you have a amp thats say 400' but the time you take into account wire resistance,each connection between the amp and the coil, the subs impedience the damping worked out to be something like 4!!.

once the impedience of the sub drops below the amps output impedience it begins to drop of! i was under the impression it halved with each halving of impedience to, but once you allow for conections and cable resistance it would be lower. no matter how long or good a piece of cable is it will have a resistance even if it very small.

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#3 Winno

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Posted 18 July 2004 - 04:38 PM

I thought that when you bridge an amp, it sees a speaker that's a nom 4 ohm as a 2 ohm load and this will therefore reduce the damping factor.

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#4 -DJ-

500 - 1500w RMS

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Posted 18 July 2004 - 07:46 PM

Winno said:

I thought that when you bridge an amp, it sees a speaker that's a nom 4 ohm as a 2 ohm load and this will therefore reduce the damping factor.

well... yeah... half the load SHOULD be half the damping fact... but whats the story with this guy's rodek then??? 400 into 4R and 120 into 4R bridged (essentially 2R)

d