Re the Indigo cable and the solid/stranded question, while a case could be made for referring to it as solid core, IMO (based on what I perceive to be the most common usages of the terms) cables employing any form of Litz construction (i.e., a single overall conductor consisting of a group of individually insulated conductors) should not be referred to as either solid core or stranded. It's simply a different animal than what both terms are generally used to refer to.
First, the combined resistance of the two conductors in a 10 foot run of 18 gauge solid core wire is about 0.128 ohms. For the OP's nominally 4 ohm speaker impedance, that would limit the damping factor seen at the speaker terminals to no more than 31, no matter how high the amplifier's damping factor may be.
Now a case could be made that damping factors above a few tens of ohms are overkill with most speakers, and that happens to be my opinion FWIW. But I don't consider my opinion to be the last word on the subject, and a lot of audiophiles and designers believe otherwise.
Second, when cable resistance is high enough to constitute a non-negligible fraction of speaker impedance, the interaction of that resistance with the speaker's impedance vs. frequency characteristics may conceivably affect tonal characteristics. 0.128 ohms is 3.2% of 4 ohms. Is 3.2% a "non-negligible fraction"? I don't know. But it seems high enough to suggest that it would be best to not take any chances, given that the percentage can be easily reduced.
On the other hand, I am aware that over the years there has been some advocacy for narrow gauge solid core speaker wire, even 20 or 22 gauge. I believe some of the writers at the British publication HiFi News & Record Review advocated for that twenty or more years ago. While I don't doubt that in SOME systems the results of that approach may be subjectively preferable, I would have to think that what is happening in most of those cases is that the cable is altering the sound in a way that is complementary to the colorations of the rest of the system. In other words, IMO it amounts in most cases to applying a band-aid.
Happy New Year to all!
-- Al
As for the OP feeding his speakers with only one solid core #18 ga wire for each + and - terminal I would not think that would work too well for the sound of the speakers or for the amp. I will leave the technical why nots to Almarg and Kijanki.I agree, as indicated in my earlier post, unless perhaps the cables are unusually short. Simply put, the resistances of typical lengths of 18 gauge speaker cable are high enough to conceivably/perhaps/maybe under some circumstances result in sonic effects that are at least slightly audible.
First, the combined resistance of the two conductors in a 10 foot run of 18 gauge solid core wire is about 0.128 ohms. For the OP's nominally 4 ohm speaker impedance, that would limit the damping factor seen at the speaker terminals to no more than 31, no matter how high the amplifier's damping factor may be.
Now a case could be made that damping factors above a few tens of ohms are overkill with most speakers, and that happens to be my opinion FWIW. But I don't consider my opinion to be the last word on the subject, and a lot of audiophiles and designers believe otherwise.
Second, when cable resistance is high enough to constitute a non-negligible fraction of speaker impedance, the interaction of that resistance with the speaker's impedance vs. frequency characteristics may conceivably affect tonal characteristics. 0.128 ohms is 3.2% of 4 ohms. Is 3.2% a "non-negligible fraction"? I don't know. But it seems high enough to suggest that it would be best to not take any chances, given that the percentage can be easily reduced.
On the other hand, I am aware that over the years there has been some advocacy for narrow gauge solid core speaker wire, even 20 or 22 gauge. I believe some of the writers at the British publication HiFi News & Record Review advocated for that twenty or more years ago. While I don't doubt that in SOME systems the results of that approach may be subjectively preferable, I would have to think that what is happening in most of those cases is that the cable is altering the sound in a way that is complementary to the colorations of the rest of the system. In other words, IMO it amounts in most cases to applying a band-aid.
Happy New Year to all!
-- Al