Way back when, I had a blond Fender bassman with 2-12s that couldn't handle much without distorting. I upgraded to an Ampeg B18 and blew that speaker a few times. I was out of it for a long time but for the last several years I do home recording. I have a small old Hartke 60 watt 1-12" bought used (fine for home) but have recently joined a band. The speaker labors at half way up so I think it needs to be replaced or a cabinet added or I should just get something bigger. So I start looking... Why are 10" so popular now? What are aluminum cone speakers like? Can new replacement speakers really handle like 100 watts rms like they claim? What is a good bang for your buck brand?
Speakers and speaker cabinet design has improved a huge amount in the last 30 years. I started playing bass about 45 years ago and I too blew speakers and could never find an amp that would really do the instrument justice or give me adequate volume. And we played a lot quieter back then. There was a bit of an improvement when the JBL and other brands of musical instrument speakers came out. But even those classics like the JBL D140 have been surpassed by the latest generation of speakers. The new ones can handle a lot more power and actually produce some audible bass and even 10" speakers have been designed to handle bass quite well. They have to with the very high powered amps available now. Speaker cabinets are now scientifically tuned (in most cases) to get the most out of the speakers used. Weight has dropped a lot with intelligent cabinet design. The Hartke you have is a bit feeble for playing live with a loud group. I'd keep it for practice at home and get a new rig. There are lots of good amps around now. I'd say go for a minimum of 200 watts and a pair of speaker cabinets like a 1x15 and 2x10. That's quite popular. A lot will depend on how loud you play, the size of rooms you play in and the type of music. I've always found that 200 watts from a good and honestly rated amp was enough power, as long as the speaker cabinets were good ones. Some guys will want a lot more like 400 watts or more and a huge stack of speakers to handle all that power..
10" speakers became popular when Ampeg came out with the SVT fridge. Many people believe that 10" speakers sound "faster" (i.e. better) than bigger speakers (12" or 15"). On the other side, you can read about 15" speakers sounding boomy and/or muffled. IMHO that is pure prejudice, since the sound of the speaker strongly depends on the cab it is built into and on the amp it is driven by. You can get a good dry and tight sound with a 1/15" cab, if it is well built.
Lots of modern drivers can handle power linearly (without distorting) far better than their predecessors from "way back when." A single 12 isn't much to begin with. Neither is 60w. Some can handle 10 times that. Others may struggle with 20w. Excursion limited power handling varies from driver to driver.
Try Eden (expensive but great) or Nemesis (also from Eden), cheaper but still great - I have the Nemesis NA320 amp plus the NSP210 and the NSP115 cab's, and they sound great and do not weigh much.
You can get very good bass from modern 10" drivers in a well-designed cabinet. Contrary to popular belief, a cab doesn't need to be flat all the way down to the lowest bass note. Cabs begin to roll off well above that point, but they still put out plenty of sound. To be heard onstage, it's usually the mids that you need, not the extreme bottom. Tens are excellent in that range, and the larger drivers are sometimes lacking there. It's easier to carry smaller cabs, and you can stack them to get the sound closer to your ears onstage.
Take a look at the Carvin web site (www.carvin.com) great gear at an unbeatable price and a ten day in home trial period. Paul