12 vs 15

Discussion in 'Amps and Cabs [BG]' started by mr e, Nov 26, 2003.

  1. mr e

    mr e

    Nov 17, 2003
    I'm looking for a powerful Combo amp. I came across a few amps I'm curious about. If a 15" Combo is 100W(Fender Rumble 100,CrateBX100,Ampeg BA115,etc) would it be more powerful/loud than a 12" combo packing 120W?
  2. PhilMan99


    Jul 18, 2003
    US, Maryland
    Power - no. Louder? Maybe.

    A 15" speaker moves more air, so in that sense, it may seem/be louder. 100W vs. 120W though would depend on the amp & tone-settings, being so close. Different manufacturers rate their "wattage" differently.

    As I recall, doubling the wattage does *not* double the volume-level. A 20% difference would be negligable, so the honesty in rating the wattage and the speaker size/quality would probably matter more in terms of sheer volume.

    BTW, if you're concerned about "loud", be sure to try before you buy, especially cranking-up the low EQ. Low-end amps are MISERABLE sounding when playing loud. The worst rattle or make a "farting" ("raspberries"?) sound, due to clipping in the pre/power-amp or speaker itself.
  3. Phil, I agree. 20 watts will not get you any noticeable increase in volume.

    What really matters is efficiency. That is, how loud the speaker can get with a given amount of power. Most are speced at 1W@1meter. All standalone cabs have this rating, I don't recall seeing it on combos.

    another thing to look for is 4/8 ohm power ratings, and if the combo has an external speaker output. Usually amps will put out much more power into a 4 ohm load, and good combos take advantage of this. Your setup will be much more efficient with an external cab.
  4. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    Man, what's up with this literal interpretation stuff? From God's mouth to my ears, indirectly by way of hundreds of generations and thousands of miles... Nice try though. Besides, everyone knows the Devil has the best tunes! :)

    Let's see, a good combo with a built in 8 ohm speaker should be "extensible" with an 8 ohm extension cab. That will make it considerably louder. For instance, I have an SWR Basic Black that's rated at 120 watts with the built in 15" speaker, and then if you plug in a Son of Bertha extension cab it goes up to 160 watts. The difference is definitely audible. It takes me over the threshold of being able to compete with a loud rock drummer.

    If you do end up going with the 12" combo, try to get a 15" extension speaker. At least one of them should be a 15, it'll give you much better bottom especially at low power.
  5. redneck2wild


    Nov 27, 2002
    Memphis, TN
    It really depends on multiple factors - the size of the speaker and the amount of power are only 2.

    But if you narrow it down to a single manufacturer that uses the same amp configuration with different speaker sizes, then the size of the speaker and cabinet makes a difference.
    For example:
    Hartke has 3 different 120 watt combos in the Kickback line - all use the exact same preamp/poweramp. But they have different size speakers - a 10", a 12" and a 15". The size of the combo also increases as the speaker size does.
    If you play two side by side - say the 12" and the 15", the first thing you will notice is that the 15" puts out deeper lows.

    Some companies will sell the same combo with an option for a different speaker.
    Peavey does this with some combos and with a number of PA cabinets.
    You may be able to buy a combo with a Scorpion 15" for a certain price or for a little more get the Black Widow 15". Both combos use the same head (preamp/poweramp) and cabinet but the models sound different because of the speaker. Some people may like the sound of the cheaper model Scorpion while other may like the sound of the Black Widow.

    Your best bet is to try out the combos side by side. Let you ears be the judge.
    When you try out combos, you may want to crank up the volume to make sure that it will be loud enough and have the tone you need at the louder volume - many combos sound good at low volumes, but the tone changes (or may even distort) at louder volumes that you might need.
  6. Chasarms

    Chasarms Casual Observer

    May 24, 2001
    Bettendorf, IA USA
    Twenty watts definately won't make an audible difference.

    At 15" driver has more than 50 percent more surface area than a 12" driver. All things being equal, the 100 W amp with a 15 would probably be louder than the the 120 with the 12.

    But all things aren't equal, the designs of the speakers themselves, the enclosures, porting, etc. will all impact performance.

    Extension capability is nice. It isn't the increased wattage from the amp that helps as much as doubling the speaker surface area.

    I know we all have budgets, but in general, I would suggest that you avoid all of the above mentioned amps if you intend to play with other musicians. A single speaker, 100-120W combo will be dimed all the time to keep up with even a modest playing drummer and even a 50 watt guitar amp. You'll compromise the life of the output stage and the speaker. Not to mention your tone will suck if you are pushing clipping most of the time.

    I'd suggest something a little more powerful used. If you can find a Nemesis 210 or 115 combo it should serve you well. They are loud enough to use with a band and sound pretty good.
  7. brianrost

    brianrost Gold Supporting Member

    Apr 26, 2000
    Boston, Taxachusetts
    I will disagree with Chasarms a bit, since I went for over 10 years playing gigs with amps from as little as 20 watts (!!) to a whopping 75 watts into a 15" speaker. Yes, these were rock and roll gigs with no PA support for the bass...in one band I was competing against a Marshall half stack! I was not blowing speakers or frying amps, either.

    Even today I commonly use only about 200 watts on gigs.

    I would agree with taking the 15" over the 12" in a combo unless size and weight are critical. That 20 watt amp I owned (an ancient Traynor) would never have cut it with a smaller speaker.
  8. The 0x

    The 0x

    Aug 24, 2003
    Timonium, MD
    Let me guess, you are looking at the Behringer BX1200. :rolleyes: