Is there an optimal interconnect lenght?

The optimal length for interconnects is determined by a lot variables. Ideally the inteconnects will be just long enough to connect components (duh) wiht just a little extra room so as not to strain the actual connections. The proper length may be detemined by a few different variables, such as allowing components to be far away from each other so that they don't interfere with each other and at the same time not being so far from each other that the interconnect becomes so long that it strains the source component. The interconnect should be of appropriate length so that cable "dressing" is best addressed without becoming part of the problem. Of course amplifiers may dictate interconnect distances. Some instances are best served by long interconnects and short speaker cables other instances may be better served with short interconnects and long speaker cables. Passive pre-amps tend to work better with short interconnects. Balanced interconnects allow for greater lengths with less compromise due to the extra length. And things like capaciatance and shielding of the particular cables and the output and input of the components attached may vary the needs. Then there is the matter of resale value. Yes there is an optimal length, but, it varies not only from system to system but from cable to cable, component to component and every combination there in. Even different environments may have an effect on appropriate interconnect length.

From an electrical standpoint, shorter is better, but keep in mind that many cable manufacturers voice their cables to sound best in the most common length, which is 1 meter.
Of course, if you have a particular model in mind, perhaps the dealer would be willing to let you audition two different lengths to determine which works best in your system.

When I was experimenting with making my own Ic's, it seemed like anything shorter than .6 meter was "edgier". I agree with Kurt tank about 1 meter length as practical size. Mike.