Update - Having played thru the Jensen more, and at higher volumes, it still sounds fantastic. The original stock speaker sounded just OK at first, but then quickly began to sound like a transistor radio speaker, if you know what I mean. It just sounded kinda 'cheap', like they put a speaker in the amp just because they had to. So I replaced that with an Emminence Patriot series 'Red, White, and Blues'. Unfortunately that spkr is 8 ohms, and rated for 120 watts. This amp is rated at 4 ohms, 50 Watts, so it lost some of the rated power driving into 8 ohms, and never really got pushed by the amps 50 watts which resulted in a ultra-clean sterile sound.
So after installing the Jensen C12N-4 a friend of mine comes over to jam, and this guy already knows I mod my Strat a lot, but I didn't tell him about the speaker change. We start playing the usual stuff, and when we take a break he says "What did you do to the Strat this time, it sounds really good". He says "It sounds warmer, and I can hear all the notes." So then I told him "Nothing to the Strat, changed the speaker in the amp."
Point is, it's not just MY ears hearing the improvement, or just me wanting to hear a change, it's an actual, noticeable difference, and for me, it's a good one.
So far I've cranked only the Clean Channel using a modded TubeScreamer, Boss PH2 SuperPhaser, and Boss DD2 digital delay with slight reverb from the amp. All the effects worked as expected, and were added one at a time after checking the totally clean sound. It all sounded really good.
Rent has just been paid, so in a couple of days I'll check out the OD channel, but since I'm really not much of a heavy metal player anyway my opinion of the sound quality of this spkr for that type of sound may not be of much value.
Please note that I'm not affiliated with the seller of this spkr, I just couldn't find any other 4 ohm 12" spkr anywhere, and all this LONG post is just my opinion, of course your mileage may vary.
As an afternote, I'm very lucky to have long suffering neighbours in my apartment building, and a beginner guitarist in another aptartment who plays LOUD, so when I play loud they are thankful that it's not quite as awful
