Hello all! I currently have a Bose L1 pro8 that I have been doing dj/karaoke gigs with. It works great for indoor spaces and medium crowd outdoor but I have a few large outdoor venues coming up. I don’t want to buy another pro8 to double my sound right now and I was wondering if anyone could recommend compatible speakers I could hook to the pro8 to increase sound output and still keep the quality I have now.
I don't have any specific speaker recommendations for you, but hook up should be fairly easy. You will need to use powered speakers, and you can connect them by connecting an XLR cable to the "Line Out" port on the back of the L1 Pro8. Most powered speakers have a "thru" jack to allow you to "daisy chain" several speakers together. However, keeping "the same quality as [you] have now" will be completely unpredictable.
One other note: Adding another L1 Pro8 will not double your volume, but will allow you to cover a wider area by spacing them apart. The "throw" (front-to-back) distance will not significantly change. Moving up to a Pro16 or Pro32, with additional wattage, drivers, and sub size will give you a longer throw over distance. There's a nice illustration comparing the throw of a Pro8 vs. a Pro16 and Pro32 in The Bose Professional Portable PA Encyclopedia at this link.