Alpha-core advise?

very nice cables

I have no doubt that the Threshold amp can deliver 500W, but that does not mean the speakers are demading all of that to require more than the MI2 cables can deliver. I personally think your cables should be sufficient and you state that you like the sound. The techs at AlphaCorps are not in conflict by saying that if you do not want to use doubled MI2s then you can use the larger MI3. And yes the impedance halves in parallel. You may benefit by looking up an old post from Sean about a Zoebel filter at your speaker inputs when using Alpha corps cables. I am very happy with the MI1 cables and this filter on a lower powered system than yours.

When I purchase my MI-2s they came with the Zoebel network already integrated into the design. No extra work on my part. It doesn't hurt to have it on their even if you don't need it from what I was told by Alpha Core.

Thank you for all the replies. I did use supplied external Zoebels when I tried these cables. Oldears, the techs (I was told they were engineers) actually did conflict. The first one said by using 2 pairs of MI 2's I would be doubling the "characteristic impedance" of 2.5 Ohms to 5 Ohms and there by creating a closer match to the speaker load. He also said that 4 lengths on the MI 1's would create a perfect 4 Ohm load, but, the binding posts wouldn't accomodate that. The second engineer said the opposite and that doubling up the lengths would halve the "characteristic impedance". As for the power output of the amplifier, let me say that it is used in a fairly large room (14' ceiling peak) and that the speakers use an active equalizer that boosts the signal below 70 Hz by up to 12 dB's. I would think that would put quite a demand on the amp. Alpha-core seems to have a funny pricing system, 2 lengths of MI 2's cost less than 1 length of MI 3's, yet they claim that the MI 3's have the perfomance of 2 MI 2's. Alpha-core claims that matching the impedance load is what makes their product special. To be fair, they also claim that absolute matching is unnecessary. From what I am led to believe equivilent runs of MI 2's would offer a closer impedance match at a lower price, the MI 3's would offer a less ideal impedance match, better/ bass control and more surface contact with "integral spades" at a greater cost. Any thoughts?

1) The nominal impedance of most any product known to man will vary as frequency is altered. This includes speakers, the output impedance of the amp, speaker cables, etc... As such, the key here is to use components that are "reasonably well matched" in terms of impedance and are capable of delivering the required amount of sustained voltage and current into those impedances without strain. It would be impossible to match impedances in a precise manner as far as the amplifier / speaker cable / speaker is concerned.

2) MI3's present a VERY low nominal impedance to an amplifier. While this can allow greater power transfer to occur, it can also "load down" the amplifier during very demanding passages with difficult speaker loads. On top of that, very short runs of MI3 connected to a reactive speaker can introduce increased non-linearities into the system. This is due to the higher than average amount of reflected EMF that the amp would see from such a low loss / low impedance speaker cable "modulating" the output of the amplifier. In effect, a slightly higher impedance ( like that of the MI2's ) can provide a bit of a "buffer" and add stability to the circuit.

3) Running multiple cables in parallel to the same set of binding posts would actually introduce erratic impedances into the amplifier / speaker equation. This is due to the variance in both spacing and geometry of the paralleled conductors, which are otherwise controlled through design considerations at the time of manufacturing of a single cable run. As such, some of the benefits of matching the nominal impedance of the cables to that of the speaker may be negated. In this respect, more is not always better, especially when one selects an optimal combination to begin with.

4) I would only recommend running MI3's for use on longer runs with VERY sturdy amps ( which are few and far between ). The MI3's lower nominal impedance, very heavy gauge conductors ( 7 gauge ) and minimal high frequency losses will tend to reduce the otherwise greater losses associated with these longer runs. Due to the higher levels of capacitance of these cables, which would be compounded by using longer than normal lengths, may require greater attention to detail in terms of the zobel's used and where they are placed in the circuit.

5) Goertz flat speaker cables require minimal break-in as compared to the mass majority of other speaker cables. This is due to both their geometry and materials used.

6) I would stick with a single run of MI2's so long as length is kept reasonable. The length that you are working with ( appr 10' ) should be fine for this application.

7) As previously mentioned, these cables provide a very neutral signal path joining the amp with the speakers. Whether or not you like what these cables bring to your system will be more a matter of how good of a job you did in selecting a suitable amp to drive your speakers instead of how much of a personal preference you have for other cabling and the colourations that they bring with them due to inferior design and materials. As such, be forewarned that better / more neutral cabling may not result in "better sound" or "sound that is more to my personal preference". If it sounds like crap with this cabling, don't blame the cabling, as the cabling is simply allowing you to hear what your system really sounds like.

Hope this helps and answers some of your questions. Sean
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