I have read this forum for probably 5 years now and I have learned a ton about how amps and cabs work. It is so great to have so many knowledgable people on here. Just so happens, I would like to get some advice from those people. About 10 years ago I purchased an Acme Low B2 4 ohm. I paired it with a Peavey 115 BX BW 4 ohm. I was running a couple of different preamps into a Mackie 1400i. It worked pretty well, i could balance the cabs with the sensitivity knobs on the power amp, plus the Mackie had hp filtering at 30 hz. I even used the crossover in my Peavey Max pre for a while to run the 115 as a sub (about 250 hz and below). That rig pushed some serious bass. Well, fast forward to today. I now live in NYC and don't currently own a vehicle. Let's just say I had to downsize a bit. Still own the Acme. Love the clarity. Bought a Genz ShuttleMAX 12.0. Along the way I acquired an old Genz 115 cab. This is the closest I can find on their site, but I think mine is even older as it doesn't have the edge lift handles. It has two 1/4" jacks and no markings or writing whatsoever other than the Genz Benz badge on the front. http://www.genzbenz.com/fa=detail&mid=1427&sid=631&cid=118 It was 8 ohm but I swapped the 4 ohm black widow out of the peavey cab and sold the peavey cab with the 8 ohm GB speaker. I now regret this, but I'll get to that in a second. These days all my gigs are pretty much one cab gigs. Lugging one of these through the subway with a bass is about the limit of my ability. The Acme has been my choice up until recently. I love the tone, the low end extension, but it just doesn't keep up with some of my bands. I was starting to wonder if the ShuttleMAX wasn't all it was cracked up to be as I can make the limit light turn on pretty quickly. I actually don't like the distortion that comes with the overload light as most of the time I just want pure, clean sound. I am a solid state guy. A couple of gigs back I brought out the Black Widow loaded Genz instead. Wow! The ShuttleMAX is not lacking. With that combination I can pretty much bury our 4 piece funk/rock band. Not that I want to but whereas I used to run the master with the ACME at 5-6 with the Genz/Peavey I run it at about 2.5-3.5. The ShuttleMAX isn't even breaking a sweat. But all is not perfect. I miss my low B string. That is the best part about the Acme, it makes everything below low E just as powerful (or more so) than the rest of the bass. I miss that. I also miss the upper extension of the mid driver and tweeter. My ideal amp would be one that I don't even notice is there. I want the amp to reproduce what I put into it. If I want more bass I will palm mute and use my thumb. Distortion? I have a pedal for that. I am considering swapping out the Black Widow for a different 15". I have been looking at the options on US SPEAKER PARTS - Speakers, Speaker Cabinets, Guitar speakers, Bass speakers, , Woofers, HF Drivers, speaker upgrades and replacement speakers. Eminence Speaker, JBL speakers, 18 Sound, B&C, EV, Tannoy, Peavey, Celestion, RCF, Jensen, Beyma, Fane, P and I have also been reading some of the (relatively) new info on the Acme site. Using Andy's box calculator (http://www.acmebass.com->science->loudspeaker design->Spreadsheet to Evaluate Specific Woofer in Sealed or Vented Enclosure), I have found what I think is a good candidate. The Eminence Beta 15-A. Here is why I think this might be the speaker for me. First, it is inexpensive. I could actually purchase this soon. Sadly, new cabs just aren't in the cards right now. Second, it is 8 ohms. On occasion I still get to use both cabs. The ShuttleMAX is 600 w into 4 ohms and 375 into 8. I have been using the formula on Andy's site to calculate max SPL. Om = (10 x log Pm) +S1, where Om = maximum output Pm = maximum input power S1 = sensitivity measured at one Watt/one meter Punching in the specs from the Low B it comes our at approx. 120db. Putting in the specs from the Beta 15 A it is in the neighborhood of 123db. This seems close enough to me that the 15 wouldn't overpower the 2x10. Third, it seems to have almost an extra octave of high end compared to the Black Widow. Fourth, it has higher Xmax than the Black Widow. Fifth, it is about half the weight of the BW. Now there are a couple of things I really like about the Black Widow. First, I know I could run totally horrible gain staging, roll it down stairs, and generally abuse it and there is a pretty good chance it will still work. I know from experience. Second, it is really aggressive and cuts through a mix nicely as long as you are on the E string or above. According to Andy's spread sheet where as the BW basically doesn't do much below 100 hz, the Eminence would give me a nice bump between 60 and 100 hz. I tend to do this bump with EQ anyway, so I think it would be desirable. My Genz cab is at the rehearsal space so I am guestimating a bout 137 liters of volume. I have no idea what the box tuning is but if it is anywhere near other published specs I have seen, I am guessing 45-50 hz. (Let's not get started on published specs.) The extra upper extension of the Eminence might just give me enough highs that slapping sounds ok even without a tweeter. So experts, is this a good idea? Maybe one of the Genz guys could chime in with some more info about this cab? Am I asking for more trouble? Insights and advice are all welcome. Thanks for taking the time to read this.