how high to bias?

[eLarson]

So I have these speakers. The nominal impedance
is said to be 5 ohms, while the maximum is 7.5
ohms and the minimum is 3 ohms.

The hitch is, I don't have the impedance curve, so I
don't know the range of frequencies over which it
dips to 3 ohms. (They are Dunlavy SC-IIs, for what
it's worth. If you know a place that shows the
measured impedance curve, let me know. I've
come up empty googling for it.)

Anyways... the question: Would it be worthwhile to
bias the output high enough to account for the 3
ohm minimum?

I suppose it is a philosophical question as much as
anything, but I'm curious to hear your opinions.

Thanks,
Erik

p.s. The amp project hasn't been chosen yet... SoZ
or a bridged Zen variant. Perhaps even the
Aleph-X that has been talked about.

 

[halojoy]

Of course

we have to take in count the lowest imp of speaker
beeing driven of a Class A amplifier.
An estimate can be, like yours 0.6x nominal imp,
or 0.5x imp.
For class AB the bias is set in another way

 

[eLarson]

The beauty of DIY is that I can try it both ways.

Or I can add a switch to kick it down to the lower
bias for times when I'm not paying close attention.
That way my electric meter won't spin like a deli
meat slicer all the time. *heh*

It does make me wonder... is there any particular
meaning behind the term "nominal" when it comes
to speaker impedance?

E.