Max. speaker 1/4" cable length ??

Congratulations on the gig.

Usually setups like this use different PA systems, using 70V or 100V systems. Also there will be some delay issues over a 200ft distance. And 4 speakers on this kind of square metres is probably not gonna be enough. You really want a larger number of (smaller) speakers. If not the line-systems (70V/100V) then at least active speakers (which also means running mains cabling).

If it’s a large marathon I am guessing there is a budget for the PA system too. I would personally not try to cover two blocks with the 4 speakers you have. Is there any way you can hire the correct PA and have it set up by the rental company? That way you only have to plug in your gear and not worry about the PA.

There is a lot more to PA (especially specific outdoor events like marathons) than just dropping 4 speakers on the street and turning the volume up. It’s as much a science and experience and right gear issue as DJ-ing is. So, unless you know what you are doing, I would let that one be handled by professionals.

I have been DJ-ing for 35+ years, am a certified live and studio sound engineer and have been doing quite a few specific events over the years. If I were asked to do a gig like you describe I -at a minimum- would consult with a rental company and get specific gear. Might set it up myself, because I DO have some experience, but that is it.

To answer your questions:

active speakers with XLR balanced cables: couple of hundred feet is no problem

passive speakers with speaker cable: here impedance comes into play. The maximum length is based on the actual wire gauge and the impedance of speaker/amp combo (there are tables you can use to determine max length). Even with very heavy speaker cable (12AWG for example) 120ft is maximum. And where XLR will give you some leeway, speaker cable won’t. General advice is to stay within a safe margin (75-80%) of maximum length. If you need to connect more cables together, make sure you use SpeakOn cables and couplers.

Final word on safety, if you are running mains to your speakers, be sure there are no places where kids can stick their fingers! Preferably the cable is “flown”, i.e. run through the air beyond reach of the audience.

Hope this helps.

Obviously XLR is only if you have active speakers (I thought the B212s are passive and require an amp, those can’t be used with XLR of course). If all 4 speakers are active, then running xlr to the first then xlr to the second is no problem, your lenght count starts at 0 when you go from the first to the second set.

Are you gonna have the speaker firing towards you ? Otherwise it would make more sense to have the first speakers close to you and the second set at 100 ft.

Perhaps the rental company is already supplying the marathon organisation with sound? Or they could see it as a bit of sponsoring or something?

…And there is me worrying about 7M XLR!