Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kagliostro on October 30, 2023, 04:46:23 pm
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In simple HiFi (or music reproduction) Speaker cabinets often there is a pair of Speaker one for Lower frequencies and other for Higher frequencies
The most simple arrangement don't use a real Crossover unit with inductors and capacitors, only one capacitor is series with the High frequency speaker is used
(https://i.imgur.com/AjXHYrI.jpg)
What I don't know is ... in this simple arrangement which is the resulting impedance of the combined Speakers ?
If I put two 8 ohm speakers in parallel I know I obtain a virtual 4 ohm speaker
But when there is a capacitor that cut frequencies like in the schematic, what happen to the resulting impedance of the coupled speakers ?
Many Thanks
Franco
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the simple answer is "it's still 4 ohms" otherwise you have to do speaker math over frequency range, plotting on log paper with slide rules n such :icon_biggrin:
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The cap is there to keep low frequencies from reaching the tweeter ( or high frequench driver if you want to call it that ) and damaging it - of course you probably know that already
Shooter has it right I believe.
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All voice-coil speakers have rising impedance above midrange.
These one-cap "crossovers" usually start past the woofer's midrange, where its impedance is near double or more.
Also you don't put a lot of power above ~~1KHz so the amplifier won't strain into a "wrong" impedance.
So yeah, what Shooter said.
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Many thanks friends
Franco
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.