So I did a dumb. I bought a used cab without looking super closely at it. It sounded good at low-ish volume when I tried it but as soon as I got it up to jam volume with the band I noticed a crackling sound. The cab is a GK 410Neo/4Ohm. Super bright sounding. Louder than I expected. But the bottom right speaker crackles while playing. The crackling goes away if you lightly touch the speaker. Sounds like I need a new speaker, or to get this one repaired. But it gets sketchier. I didn't notice at first, but one of the speakers is a different colour than the others. The bottom right is a weird blue colour. I took the speaker out and it's labelled "TC410NEO"... which makes me think Traynor. Sure enough, the Traynor neo 410 cab has those same blue speakers in it. Of course, that's an 8 ohm cab so it seems unlikely it's a proper match for what's supposed to be in here. I went to the GK website to try to find replacement speakers and was able to find what looks like the right replacement, but they show as out of stock. I emailed but it's the weekend, so gonna have to wait. In the meantime, I'm curious what else I could get away with. I suspect that I can't quite just throw any other two 10"/16ohm speakers in here without throwing something off? I mean, the Traynor speaker being in there didn't sound bad, but I imagine something about it being there contributed to the other failed speaker maybe? There's only a couple of options, and they're rated at a slightly lower power than the original ones. Is it a terrible idea to use speakers that aren't meant for the cab? Is it a terrible idea to mix the two good speakers with two of a different brand but the same impedance? There's a shop nearby that can get some Basslite SC10-16 speakers, which seem promising if I can't get the original GK speakers. I welcome any and all advice and info.