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In Reply to: Wiring up my Paramours and Theater 4 Pi Loudspeakers- Help! posted by Garland on January 06, 2002 at 10:49:17:

Hi Garland!
You wrote:
>> Since I'm primarily going to use the Paramours with these 101dB
>> rated speakers what internal/ crossover wiring and what "speaker"
>> cabling would you recommend.
Use high quality, 18 guage, stranded copper hookup wire. Do not use thin single-strand wire, such as is often used to wind electromagnets. Also do not use a larger single-strand, solid core conductor - Use stranded, copper wire instead. You can use some of that audiophile "monster cable" stuff, but I wouldn't recommend it - There is no difference between this and a good, standard interconnect of equivalent size and braid except price.
>> I prefer DIY to keep costs down. I anticipate building long
>> interconnects and short speaker cables. The crossover is going to
>> be mounted externally and I probably will hard wire all speaker
>> cable connections,ie. no binding posts except at the amp. Should
>> the interconnects be shielded?
Shielding is not necessary, but you might use a twisted pair or at least run them close together, the way zip cord is made. If the cable is very long, you may want to use something larger than 18 guage. Make certain that the length of the wire adds no more than half an ohm. You can consult wire guage charts to find resistance per foot for standard interconnects. And don't forget that you must double the wire length when calculating resistance of your interconnects, because you have a balanced pair ("plus" and "minus" leads).
>> Somewhat related: the Theater 4 Pi's have a relatively low woofer
>> impedance at resonance @52ohms, I believe it is. The design calls
>> for a zobel network across the woofer of an 8 ohm 100W resistor
>> and a cap of 20uF.
The Zobel is for de-peaking the resonant created between the voice coil and capacitor in the second order Butterworth low pass filter that makes the woofer crossover. It is a high frequency phenomenon, and not related to the woofer's impedance at resonance at all. Do not omit the Zobel.
>> Do these woofer characteristics have any impact on the output
>> stage of the Paramours? ...or the Coupling caps?
Typically, where impedance peaks, power coupling is reduced. That's why we strive to use speakers with a very linear impedance curve. I've seen 100 ohms at resonance is actually quite common, and some woofers reach as hight as 200 ohms. 50 ohms is very good, so I think you'll find that the speakers and amplifier will work well together.
>> Can the 100W resistor be de-rated to lower wattage due to the 2.5W
>> of the Paramours?
Yes. You may use non-inductive 10 watt resistors instead. For that matter, you could use a 5 watt or a 2 watt part. But the 100 watt component only costs ten dollars, quantity one at full retail. It is easy to mount and assures that if you ever play your speakers on a larger amplifier, they'll be ready for it.
>> What is your opinion of Zobels in the first place?
I don't like them, because I like to have a minimum of reactive devices in circuit. But don't forget that in electrical filters, some reactive devices cancel others, so adding them actually removes reactive effects. That's what the Zobel is doing here.
Take care!
Wayne

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Re: Wiring up my Paramours and Theater 4 Pi Loudspeakers- Help!