9 gauge vs 12 gauge Jumper of same brand cable

The short lenght of the cable involved would negate any differences due to the differences in gauge. I would just use the 12 gauge.

I had such a setup a few years back. I let the dealer talk me into the '12' jumpers / along with the '9' wires.---I listened for 14/18 mos.---Then I picked up another set of '9's with bananas to go with the spade version, Together;-----WOW----. Thought I had Vahalla wires. (Have to exaggerate to make the point)

Although Newbee made a good point, the strands used in both Oval 9 and 12 are different. In this case, it would affect the sound more than total AWG for impedance matching. If you insist spend the money and buy the jumper cable, I would definitely go with the Oval 9s.

Thanks S23chang.
Do you think I should go for Bi-wirng with Bi-Oval 9(same cable geometry as my Oval 9 ,in double run biwire configuration/ 4 connecters on spkr end,2 on the Amp end )?
I would appreciate your(and other reader)opinion and suggestion ;in a way to get reassurance that Bi-wire is the way to go(despite of some downsides such as less/leaner Bass,less coherent ect as some have reported )
Thanks in advance
Simon

The result will vary from amp/speaker matching.
We did an experiment and got different result.

Using same pair of bi-wire speaker:
Setup A - Stock brass plate jumper
Setup B - Bi-wire cable
Setup C - 3rd party jumper cable
Setup D - Two runs of identical single run cable
We have tested with 4 different amps and got mixed results
All concluded that setup A is the worst sounding with all 4 amps.
Setup B, C, and D are very similar
In some amps, setup D works the best. More clear, transparent. Improvement in low frequency.
Almost no difference between B and C

This is subjective test with our setups and systems.
Although it is not the most scientific way, it gives listener a general idea about bi-wiring.

Thanks again ,S23chang. for such illustrative and helpful informations.
On setup D - is it 2-pair of identical cable with stacking up the spades on both end with the jumper remained in place ? or having the 4 spades connected to Upper and Lower spkr binding post / while only 2 spades connected to Amp end (jumper removed)
I really need your confirmation ,please
Thanks
Simon

In setup D, the jumper brass plate was not in the picture.
Yes, two pairs of identical cable running parallel.
On the amp side, there is only one set of output, we use banana plugs for the convenience to stack them.
On the speaker side, we run bare wire to each upper and lower binding post.

Hi,S23chang .
just for my better understanding- Is the Setup D the exact same as "Discrete Biwiring"?
Thanks
Simon

YES. Discrete Biwiring is the setup D