Another speaker cable question?

I have recently started a DIY speaker cable project, while discussing my project with a friend I explained that I intended to shield the cables. He in turn suggested that the shield is most likely not necessary and it will add to the inductance of the cable. as a result of this conversation, I started to research about shields, inductance, capacitance and resistance of various cable designs and geometries as well as their impact on the speaker amplifier system.

My research has led me to ask the question, can I predictably design my speaker cables to be optimal for my speakers and amp or am I wasting my time and I should stick to a trial and error approach?

My design variables are, wire gauge, braided or not, shielding or not, and length. Others that I am not considering but could be are, material copper vs. silver, and insulation materials.

My speakers are Monitor Audio RS6 that according to stereofile range between 4.5 (@ 165hz) to 18 ohms. My amps are quick silver mid mono driven by kt-88 tubes and speakers are connected to the 4ohm taps.

My feeling is should design two cables each at the extremes of the inductance spectrum. What do you think?
Hi Nick,

After looking at the impedance curve of your speaker, I don't see cable inductance as being particularly critical. Keep in mind that the impedance presented by inductance ("inductive reactance") is directly proportional to frequency, and any significance it might have will therefore occur at upper treble and ultrasonic frequencies. Your speakers have reasonably high impedances at those frequencies, much higher than the inductive reactance of a moderate length of cable having reasonable inductance per unit length, and therefore there should be little if any sensitivity to that inductance.

Also, depending on the cable design, ultra-low inductance can often go hand-in-hand with extremely high capacitance, which your amplifier might not be happy with.

Another consideration that is sometimes applicable is the possibility that noise picked up by the cable can enter the feedback loop of the amplifier, if it has one, potentially resulting in effects within the audible spectrum. Shielding obviously could help that, but I agree with your friend that chances are it wouldn't be a problem without a shield, especially if the + and - conductors are twisted and/or braided together (so that noise is picked up equally by the two conductors). Twisting will lower inductance and raise capacitance, btw.

All in all, my instinct would be to avoid any extreme parameters, and beyond that to proceed essentially by trial-and-error.

-- Al
Al, thanks for the response as usual it is extremely helpful.

I started my trial an error testing last night with two pairs of cables i had lying around. The pair i am currently using (18awg 3ft long, with each wire indipendent from the other)and an old pair i made (12awg, 8 ft lg, solid core wire with both wires snugly bound in a tech flex sleeve)

Based on a calculator i found online for capicitance and inductance capacitance calculator and based the geometries here are the relative readings

18awg: higher resistance, lower inductance, much lower capacitance (each wire, signal and return, is far from the the other)

Listening results are that 12awg presents a vailed sound with more pronounced but slightly muddier bass. The 18 awg is much more enjoyable.
Listening results are that 12awg presents a vailed sound with more pronounced but slightly muddier bass. The 18 awg is much more enjoyable.
Nick, what you are doing w/ your DIY speaker cable project is commendable 'cuz there's nothing like doing & learning in the process.
However, your DIY cable project has many variables some of which you have already stated in your OP. One other variable (which I bet you did not think of) is that thicker gauge cables vibrate when music passes thru them & when they are suspended connected between amp & speaker. I know this 'cuz Virtual Dynamics in Canada used to use OCC solid core very thick gauge wire for his speaker cables - the lower end cables used 14AWG & the higher end cables used 12AWG, 10AWG & his top-of-line (I think Genesis?) used 6AWG wire. Very stiff cables & very hard to work with - had to pre-bend them before installation. These Virtual Dynamics cables were very heavily dressed in vibration damping material (micro steel balls for his lower end designs & micro brass balls for his upper end designs) to basically damp the vibrating cable. Otherwise, by Virtual Dynamics' own admission, these heavier guage cables sounded dull & flat, which is what you are hearing, I believe.
Yet another manuf believes in wire damping - Music Note/Sonoran by StarSoundTech & he even sells micro bearing steel fill

So, you might have made a hasty conclusion with the 12AWG cable as, I believe, it is not properly prepared to be an audiophile quality speaker cable just yet. You have some work to do before you beat the negative mechanical effects of the thicker gauage & level the playing field vs. the 18AWG cable.

This might be why several other manuf, like Cardas, use independently insulated stranded wire (Litz) for their speaker cable.

I'm afraid there's a lot to making an effective DIY speaker cable.
You might also want to search the web for the following in quote "Jon Risch speaker cable receipe". Many of Jon's designs are proven by a huge cadre of DIYers across the globe over a long period of time. His designs might save you a lot of time......
Good luck!
Bombaywalla, Learning is what it is all about. So far so good. It is funny you mention Virtual Dynamics, their cables were the inspiration for construction of the 12awg solid core cables or at least for the use of solid core conductors. I chose 12 awg, because I figured bigger is better.

Unfortunately, this design is not compatible with my system, and all the vibration dampening in world is not going to change it. My guess regarding the reason for my dislike of the 12awg solid core cables is that the cables are 8ft long and I have mono-blocks placed right next to my speakers. The large coil of cable looks pretty ugly...

I re-checked the values of capacitance and inductance using the calculators from my post above and all though there are signficant differences, especially in capacitance between the two cable designs the order of magnitude is neglible, that is 3 and 30 picofarrads. Moreover, if I am not mistaken high capacitance should make the sound brighter not muddier.

I'm still trying to learn, and most of all I am having fun doing it.