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Bridge mode and damping factor

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Sonic the hedge View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Sonic the hedge Quote  Post ReplyReply Direct Link To This Post Posted: 21 May 2020 at 11:17pm
Not wishing to contradict myself (again!) but something else came to mind regarding back EMF and amplifier DF figure.

Certain well known Class D manufacturers claim that their amplifiers can recycle the back EMF from drivers, into the amplifier's PSU, recharging the caps. 

If, as some would suggest, the back EMF from drivers is most all dissipated by the VC as heat, such recycling claims by amplifier manufacturers would seem to be pure marketing horsesh1t. Which is of course possible.

However, there is still this issue, around cabinet/driver resonance, and effect on impedance curve.

Originally posted by Sonic the hedge Sonic the hedge wrote:

...driver impedance is not equal to DC resistance, nor is it constant across the frequency spectrum and most especially around any resonant peak(s) in the driver loaded in a particular cabinet, the exact region(s) where effective damping is most important (Just IMHO, as I have said before sound is subjective!).

So perhaps, there is something in it. 

The maximum back EMF, seen by the amplifier, occurs at exactly the point(s) where the driver/cabinet impedance curve drops to a minimum. The exact same point(s) that an amplifier headroom boost, from recycled back EMF, will be most useful, in preventing clipping (due to lower impedance/increased output). In which case, these class D manufacturers may be on to something quite ingenious.

That would also mean, that perhaps relatively higher amplifier DF figure can be quite important, but only if the amplifier has plenty spare current available too

e.g. class A/B or G/H amplifier in bridge mode, loaded and leveled to provide 1.5x - 2x headroom. Of course the class D still does it more efficiently, but the result is the same.

I'll get my coat LOL





Edited by Sonic the hedge - 22 May 2020 at 10:42am
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singingfish View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote singingfish Quote  Post ReplyReply Direct Link To This Post Posted: 31 May 2020 at 3:22pm
I may be wrong..
but here goes.

Is it correct that two or four matched drivers in an enclosure actually damp 'each other' electrically and by air pressure damping?
If true, his would mean that ganging up drivers would present an easier load for the amp to drive/control, wouldn't it

That was always my assumption anyway.

very interesting thread.

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