Newsgroups:aus.hi-fi
Subject: Re: bi-wiring
From: Rod Crawford
Date: Fri, 23 Oct 1998 19:23:56 GMT

(This is a reply to a query from "Steve" on the merits of biwiring).

One of the first major battles I fought (and won!) 3 months after joining Linn Products in Scotland as their senior loudspeaker designer was to get bi- and tri-wiring accepted for their new range of loudspeakers (Nexus, Kaber etc) which replaced their highly respected Isobarik, Kan etc. The Linn sales guys had been rubbishing bi-wiring because it had just been introduced by one of their competitors - the NIH (not invented here) syndrome. Fortunately, Linn had a 'blind listening' policy and the sales guys were blown out of the water by the huge difference bi-wiring made to the Nexus prototypes I was developing. Bi-wiring means connecting each drive-unit in a loudspeaker to the amplifier through separate leads. My experience over the past 12 years is that it improves the clarity of all loudspeakers. This should always be good but it can be bad in poor loudspeakers/audio systems or poor recordings where improved clarity just shows up the faults more. The best theoretical explanation I have come across of this (provided by Hitachi, as I remember, who own the patent for bi-wiring in Japan, when trying to sue Linn). When a current is pushed forward by the amplifier through the voice-coil in the magnetic field of a loudspeaker driver, the voice coil and attached cone move forward - the electric motor effect. However, the voice coil moving in the magnetic field generates a back voltage - the electric generator effect. In a perfect driver, the back voltage matches the forward voltage, giving rise to the driver's dynamic impedance. In the real world, the back emf is distorted by nonlinearities in the magnetic field etc giving rise to harmonic distortions and so does not exactly cancel the forward voltage. These harmonic products from one driver's terminals end up across other drivers in the loudspeaker if they have common terminals and can cause further muddling of the sound. By connecting each driver through separate leads back to the amplifier, the distorted harmonics generated by each driver can be short-circuited by the low impedance output of the amplifier. Whatever the theoretical explanation, bi- and tri-wiring can make a big difference to loudspeakers and can be the most cost effective improvement you make to your system.

Regards Rod
PS I have no shares in cable companies!

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Newsgroups: aus.hi-fi
Subject: Re: bi-wiring
From: Rod Crawford Date: Fri, 30 Oct 1998 19:29:17 GMT Steve Miovski
wrote:

Rod Crawford wrote a lot of stuff about bi & tri-wiring.... Sounds expensive... I mean all those extra amplifiers...It must be real pain to set up the levels for each driver? Are people really this fussy about the harmonic distortion that supposedly get introduced into the other drivers whilst connected via common leads?? Hey don't get me wrong... I like clean sound just like the next guy.. but I find it hard to believe that people actually listen out for this while listening to their fav' CD or watching a movie... If so I wonder if these people actually get to really listen to the music, or are they always just listening for imperfections?? P.S. This is just my opinion...

Regards... Steve :)
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Hi Steve

In my posting, I was talking about bi-WIRING (as the original question from Scott asked) - you seem to talking about bi-AMPING. BIWIRING just involves connecting an extra length of speaker cable (+&-) so that each drive unit of a speaker is connected back the same terminal of your amplifier. The cost is that of an extra length of cable for each speaker, say 2m , or 4m for a stereo pair. You can buy reasonably decent speaker cable from Jaycar for $2-4/m. Total cost = $8-$16 and 2 minutes work. My experience over 12 years since I first introduced it at Linn is that it improves speaker clarity by 20-30%. If you own $1000 speakers, it is equivalent to upgrading by $200-300. Seems fairly cost effective to me. Bi-AMPING involves connecting each driver to a separate power amp (as you describe). It results in a further 20-30% improvement in clarity but at the cost of another power amp - say $500-1000. Not so cost effective and something I have not done. I accept that extra clarity is not important to everyone - just as bass power which blows car windows out is not important to me (though quite common in the US). I listen to a wide range of music - from Steve Vai's "Fire Garden" to Franz Schubert's "Death and the Maiden". To me, it is important to know whether it sounds like Steve Vai's or Jimmy Hendrix guitar playing and so clarity is important to me. In my original posting, I was simply suggesting that there is sufficient empirical and theoretical evidence that people should give bi-wiring a go. In the end, yer pays yer money and yer makes yer choice.

Regards Rod

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