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In addition, it prevents over- and under pressure behind the dust cap when the 

cone moves back and forth. The advantage is a more dynamic and precise sound 

reproduction. 

The aluminium Centre-Plug also has a cooling effect on the voice coil, providing 

greater power handling capability and very importantly, a stable sound reproduc-

tion when playing loud.

The mid-woofers all feature lightweight 2-layer voice-coils in order to achieve maxi-

mum “attack” (the ability to start and stop precisely) and minimum distortion. These 

acoustic properties are of utmost importance for optimum voice reproduction.

Active Impedance Control

All C 80 mid/woofers feature Active Impedance Control (AIC), an innovative exten-

sion of existing techniques to reduce distortion in electrodynamic loudspeaker 

drivers.

When a voice coil is moving in and out of a magnet gap, it changes induction. When 

the coil moves inward, the induction increases and vice versa. This causes the cur-

rent from the amplifi er to be modulated, creating very audible distortion.

Furthermore the current fl owing in the voice coil modulates the magnetization of 

the magnet assembly which also causes distortion of the current.

By using an extra coil, placed inside the voice coil with opposite polarity to the 

voice-coil winding, the inductance variation and the fl ux modulation can be signifi -

cantly counteracted.

The effect of AIC is a clearer midrange with a markedly reduced in ‘roughness’, es-

pecially noticeable on vocal reproduction. In fi gures, this amounts to a reduction of 

third-order harmonic distortion of around of 6dB (ie a 50% reduction).

Summary of Contents for C 80 SUR

Page 1: ...TECHNICAL DESCRIPTION Jamo C 80...

Page 2: ...2 Contents General description 3 The products 4 Drivers 11 X over 17 Cabinets 17 Specifications 18...

Page 3: ...y the iconic Jamo D 5 and E 8 speakers employ ing the symmetrical arc shaped cabinets from the former and the curved top from the latter This combined with well established Jamo driver technologies DT...

Page 4: ...back box this speaker works very well when used without a subwoofer If you want some extra bass e g for a surround sound solution just partner it with a subwoofer for extra low fre quency weight The...

Page 5: ...ile the lower terminals connect to the mid woofer and woofer This split was chosen in order to separate the heavy current flow in the midrange and bass from the more delicate signal going to the tweet...

Page 6: ...ogy based amplifier delivers no less than 1800W more than enough to secure sufficient headroom even for a subwoofer reaching down to 20Hz 6dB Amplifier The important thing with subwoofer amplifiers is...

Page 7: ...ge limited amplifier it possesses tremendous dynamic power capability MFB Motional Feed Back servo control We have given precise timing extremely high priority in the C 80 design To enable the relativ...

Page 8: ...mpensates for the room influence at low frequencies as any room am plifies the lowest frequencies The magnitude of the room s amplification depends on the actual room and where you are positioned norm...

Page 9: ...tandby mode thereby missing the start of a new action packed sequence like for example an explosion or a kettledrum Besides the auto on standby mode we have there fore implemented a mode were the subw...

Page 10: ...try do the daily job for you Phase and Cut off controls Place the subwoofer where it is most convenient the controls ensure that the sound from the subwoofer can be adjusted to blend seamlessly with t...

Page 11: ...rm dispersion pattern in the treble and midrange frequencies In general the dispersion gets narrower the higher the fre quencies and this applies to both midrange and treble Consequently in the area w...

Page 12: ...The voice coil former is made of aluminium for optimum heat dispersal The voice coil is made of copper plated aluminium wire This is because aluminium weighs less than copper but the copper plating i...

Page 13: ...vy demands on the diaphragm materials stretching and compression properties the composite fibre material is composed of a special mix of different types of fibres and treated with a tough hardening re...

Page 14: ...ere it is needed around the voice coil Last but not least the very rigid material ensures that the heavy magnets and the voice coil are always perfectly aligned with the voice coil in the exact centre...

Page 15: ...exten sion of existing techniques to reduce distortion in electrodynamic loudspeaker drivers When a voice coil is moving in and out of a magnet gap it changes induction When the coil moves inward the...

Page 16: ...ice coil wire results in the so called B L Product In popular you could call this the size of the engine in a loudspeaker Sub Woofer The 10in woofer features a vented magnet system and a 50mm 2in alum...

Page 17: ...ple layers of MDF board high frequency glued together for optimum surface contact between them The arc shaped design itself results in a much more rigid panel compared to a flat panel and to further i...

Page 18: ...45 24 000 Impedance Ohm 6 Crossover frequency Hz 2000 Dimensions HxWxD Mm 380 x 225 x 341 In 15 0 x 8 9 x 13 4 Name C 80 CEN System 2 way bassreflex Woofer mm in 2 x 155 6 Midrange mm in Tweeter mm i...

Page 19: ...19 www jamo com...

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