biwire trick


Some of you seasoned vets may have heard of this, but I had never thought about it. Researching jumpers led me to Music direct's website, where in the description of some Nordost jumpers it read to try switching one lead from both mid and tweet. IOW take the positive lead from the tweeter and swap it with the pos lead from the mid.

I have a true biwire setup (separate runs for mid and tweet), don't know if this makes a diff, but the sound definitely improved: fuller, more natural, larger stage. try it as one of the easiest, free tweaks to do. You may be surprised.
tholt
I love all you pessimistic audiophiles out there. For us, it's "prove it."

The reason I tried it is as follows from the aforementioned description of the Nordost jumpers on MD:

"Diagonal Bi-Wire
For those looking for maximum performance from their bi-wire speakers, Nordost has a recommendation. Connect your speaker wire to the speaker as follows: Red lead to the Red midrange/bass post, Black lead to the Black tweeter post. Then insert the Norse Jumpers as you normally would, sit back and hold on to your socks. The effect is astounding, with greater focus, detail and less haze and grain. We don't really understand how it works, but it does so try it for yourself!"

This theoretically could make sense. I translated it to evening the load between cables, though perhaps Almarg has more properly defined it. I really shouldn't have described it as a tweak or trick, since I really don't believe it is one. It's switching the leads.

3 things can happen: it sounds worse, it sounds the same, it sounds better. You be the judge on how neutral your analysis is. Don't think about why it should or shouldn't work. It wasn't very hard for me to hear a difference. Make sure to turn off the amps first.

01-02-11: T_bone
I vote Dcrugby's post as Post Of The Day.

Almarg, I can no longer count the times I have learned something new from your posts.

Audiogon moderators,
Would you consider a 'Post of the Day' button/link one could push next to each post?
T_bone (System | Threads | Answers | This Thread)

Almarged! Almarg, thank you for your insight and wisdom, always.
I must be a little sow today as I can't seem to wrap my head around this hook up scheme. Someone please try to straighten me out. If I am getting this right, this would leave the negative mid/bass post with no connector attached to it at all. Is this correct?
Thanks very much for the nice words, gentlemen.

Rcrerar, no, what Tholt is describing is a conventional biwire arrangement but with the + conductors of the two cables interchanged at the speaker terminals. It may not have been clear to you that the statement he quoted from the MD site is addressing something different, a non-biwire arrangement in which jumpers are used but the connections of the + and - conductors of the single speaker cable are made to "diagonal" speaker terminals, rather than adjacent speaker terminals. I have no idea, btw, why the latter would make a difference sonically, although a number of people have claimed in past threads that it did for them.

Shadorne, neat calculator that you linked to. I agree that if the two sets of cables are within the same jacket, the effects I described would probably be reduced to insignificance. However, if they are physically separated by some number of inches or feet over a significant fraction of their run length, I think that the following factors would make those effects more significant than the calculator would seem to indicate:

1)The calculator assumes the speaker is purely resistive. Dynamic speakers will tend to have an impedance at high frequencies that is somewhat inductive, due to tweeter voicecoil inductance. Cable inductance will have a greater effect on bandwidth when it is connected to an inductive impedance than when it is connected to a resistive impedance of the same magnitude.

2)The speaker impedance at high frequencies may be less than the 8 ohms that is assumed in the calculator.

3)While the effect may amount to only a db or less at 20kHz, which I agree is insignificant in terms of steady-state frequency response, as you certainly know our hearing mechanisms give increased emphasis to the leading edges of rapidly changing transients. Fast leading edges, of course, correspond to high frequency spectral components.

The bottom line is that I'm not asserting that the effects I've described are necessarily the explanation of what Tholt perceived, but that there is technical rationale that is sufficiently plausible for this tweak to not be dismissed as placebo effect.

Best regards,
-- Al
Post removed 
Al,

The majority of tweeters are above 6 to 8 Ohms in the 10 KHz to 20 Khz range - rising with frequency due to the inductance. So the applet formula in the link is a pretty good approximation for the 10 KHz to 20 KHz range.

I think we can all agree that below 10 KHz we can pretty much ignore the effects of cable inductance.

In the applet I used 5 meters of speaker cable with + and - leads separated by 1 meter in order to get a 0.25 dB drop at 20 KHz compared to 200 Hz. I deliberately used an "extreme example" to show that the effect is very small in all situations.

However, the effect does exist and you are absolutely right that it might be audible in some situations. I stand corrected.

I would argue that this "trick" is definitely the wrong way to bi-wire speakers - at the very least it goes against normal way to make electrical connections which is in general to use either two wires side by side in close proximity for low frequencies (audio) or a coaxial cable for ultra HF applications.