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Theater 4 Pi + .5mh in woofer circuit... Wayne ? [message #41184]

Thu, 01 May 2003 11:34

Neo
Messages: 33
Registered: May 2009

Baron

To my ears, the upper frequencies of the woofer seemed too much, so aftering upgrading to AlphaCore inductors, I tried putting the original inductors in series with the new ones. That was too much antenuation. So I ended up ordering .5mh AlphaCores and putting them in series, to give 1.5mh. By my ear it sounds better. What have I done?

Thanks in advance...
Tom

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Re: Theater 4 Pi + .5mh in woofer circuit [message #41186 is a reply to message #41184]

Thu, 01 May 2003 11:43

Wayne Parham
Messages: 18787
Registered: January 2001

Illuminati (33rd Degree)

You may have conditions in your room that make the midrange a little "throaty." Adding a series coil would tend to attenuate the midrange - If used with a Zobel, it will introduce an additional first-order low-pass pole and if used without, a broadband attenuator that works throughout the vocal range.

Did you use the Zobel woofer damper?

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Re: Theater 4 Pi + .5mh in woofer circuit [message #41187 is a reply to message #41186]

Thu, 01 May 2003 12:58

Neo
Messages: 33
Registered: May 2009

Baron

Yes... I used the Zobel damper. That's the 20uf with 8 ohm resistor in parallel with the woofer... right ?

I read your presentation "Crossovers 101", the one you gave at the Mid-West AudioFest(I planned on going... but had to cancel). It seems to build the Theater 4 Pi cross-over a step at a time. I loved the graphs. Thanks for all your work.
I noticed one graph increased either the zobel cap or the 20uf cap in parallel with the woofer (I don't have it in front of me) and the graph seemed to antenuate to mid-range too. Would that be another/better way ?

Thanks...

Tom

P.S. I have 'ringing' in my ears. Maybe that makes me sensitive to a prominant high mid-range ?

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Re: Theater 4 Pi + .5mh in woofer circuit [message #41188 is a reply to message #41187]

Thu, 01 May 2003 15:12

Wayne Parham
Messages: 18787
Registered: January 2001

Illuminati (33rd Degree)

Increasing shunt capacitance will attenuate higher frequencies, but as you saw in the charts, the capacitor on the Zobel has a pretty wide tolerance of values. You have to make fairly large changes in the capacitance value to make a difference. The larger the capacitor is made, the more the Zobel begins to act like a pure resistor in shunt across the speaker.

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Re: Theater 4 Pi + .5mh in woofer circuit [message #41194 is a reply to message #41188]

Fri, 02 May 2003 03:20

Neo
Messages: 33
Registered: May 2009

Baron

Hi Wayne,

My Zobel is connected directly across the woofer, with the inductor before it. Just like the 4 Pi crossover schematic you sent me with my Theater 4 Pi plans.

I am interested in Spice. After I upgrade my computer (I now have a 95mhz cpu with Windows 95), I'd like to get a copy. Thanks for including it in your reply. It's a circuit simulation program... right ?

Thanks for your help...

How do you like your Paramours ?

Tom

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Paramours [message #41200 is a reply to message #41194]

Fri, 02 May 2003 10:54

Wayne Parham
Messages: 18787
Registered: January 2001

Illuminati (33rd Degree)

I like the Paramours. They don't seem to care about load impedance fluxuations nearly as much as other SET amps I've heard. Even speakers with pretty high impedance peaks work pretty well with them. The bass is great and the rest of the audio range is nice too.

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Re: Paramours [message #41207 is a reply to message #41200]

Fri, 02 May 2003 14:45

Garland
Messages: 269
Registered: May 2009

Grand Master

Hi Wayne,

Does that mean you'd revise your standing recommendations concerning the suitability of the Stage and Professional series Pi loudspeakers for use with Paramours? I would love to try out some JBL's at some point and also wouldn't mind a slightly smaller cabinet as well; smaller than the Theater 4's, that is!

Garland

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Re: Paramours [message #41209 is a reply to message #41207]

Fri, 02 May 2003 15:26

Wayne Parham
Messages: 18787
Registered: January 2001

Illuminati (33rd Degree)

I never really meant for "tube friendly" speaker recommendations to apply solely to the Paramours. It is just a general observation that low-power amps are often more sensitive to their load than high-power amps. It has a lot to do with output impedance, feedback and amp configuration. The Paramour seems less sensitive to load than some other SET's I've heard.

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