Stuffing a Sealed NHT 1259 Enclosure

[jdreier]

I am building my first speaker, a Sealed SUB with a single NHT 1259 in it. I have this quote from Ken Kantor, which I read from Bill Eckle's web site.

http://www.wmeckle.com/1259/1259.htm

The quote...

In another message Ken Kantor added (excerpted):
"Exact enclosure volume is not critical, and stuffing can be added or subtracted to fine tune the response. I recommend adjusting the stuffing by monitoring the impedance versus frequency
of the sealed box system. Add stuffing to lower the frequency where the impedance is highest. When that impedance peak starts to rise in frequency, you have added too much. The NHT/SW3p uses 820g of acoustic polyester stuffing with the 1259, but your enclosure may do better with slightly different amount."

How, exactly, do I do this???

Do I connect my signal generator and my ohm meter to the binding posts and find the frequency of maximum resistance. Then add stuffing until that frequency is as low as possible?

If this is the case did Ken mis-speak when he said "impedance" and he should have said resistance?

I really do not know how to measure impedance? How do you measure the reactive part of the impedance?

Or am I way off base and Ken meant something completely different?

Please help me out. it is my first time.

Thanks

James

[sreten]

Your method is perfectly sound.

Measuring resistance (actually voltage across the driver, you
need a series resistor for current drive to the loudspeaker)
if fine for identifying the in box resonant frequency.

Its a lot easier to just use 800g of stuffing.

sreten.

(Around 50R resistor is needed, but value is not critical.
Unless your signal generator has a current source mode)

[jdreier]

Thanks for the reply but you have confused me a little.
Remember, I only know enough to be dangerous and absolutely no more

You said my method is perfectly sound.

My method is to measure the resistance in ohms across the speaker terminals.

But then you say to measure the voltage not the resistance.
Which should I be measuring (V or Ohm)?

And do I need a resistor in series with the driver?

Thanks for your help.

James