A question of volume?

Discussion in 'Amps and Cabs [BG]' started by Square, Apr 15, 2012.

  1. Square


    Apr 9, 2012
    Yes, yes it is a question of volume.

    I have recently purchased an Ampeg PF-500 with a matching 1x15 cab. I have stated before that the variety of sounds that live in there is remarkable. I have, however, thought from the beginning that it wasn't terribly loud. Not at all what I would expect from "300 watts into a single 15... For example you can almost be heard at normal conversation levels... Almost. I think a hard drummer would bury you pretty handily.

    Tonight I went to a buddy's house and took my bass. He has a Fender Rumble 350(350 Watts into 2x10). Much to my chagrin, that amp is easily twice as loud as my Ampeg. Same "bedroom type environment, same bass; ***?

    Okay on the other hand for my set of ears the Ampeg is in another world when you consider the tone production aspects of the pair.

    So my question: Does the volume thing sound right or do I have a bum head perhaps. Seriously double the volume, maybe more.
  2. Jim Carr

    Jim Carr Dr. Jim

    Jan 21, 2006
    Denton, TX or Kailua, HI
    fEARful Kool-Aid dispensing liberal academic card-carrying union member Musicians Local 72-147
    Compare them in the same space.
  3. My guess is the two amps had different EQ and gain settings and that’s what made the big difference, or maybe design, or it’s possible you have week amp.
  4. Agreed. Or the PF's volume doesn't kick in all the way. Some amps have a very sensitive volume knob and some don't. If you haven't tried cranking the PF through the cab then I'd say try that, though back off if your speaker starts to complain. If the speaker farts out at too low of a volume you need to add another cab to your rig.
  5. seamonkey


    Aug 6, 2004
    Volume knobs, EQ knobs are not calibrated to all work the same from amp to amp.
    Turn the knobs differently for each amp.

    Not all cabinets are equal in volume. Especially with totally different drivers and designs.
  6. Square


    Apr 9, 2012
    The rooms were roughly the same... Bedroom filled with music gear, and me sitting in a chair in front of each with the same bass.

    The difference I describe is not at a given same setting. I have taken the Ampeg and tweeked it for all its worth in terms of volume. The little fender I never turned up past 1/2 way and the difference was stark.

    I'm thinking I'll send it back and have them send another to see what that does for me.
  7. Jim Carr

    Jim Carr Dr. Jim

    Jan 21, 2006
    Denton, TX or Kailua, HI
    fEARful Kool-Aid dispensing liberal academic card-carrying union member Musicians Local 72-147
    Compare them in the store!
  8. Fender not past 1/2 way?? On the volume dial? Might it not go much louder even if turned all the way.
    Not all volume knobs have near same taper
  9. Square


    Apr 9, 2012
    My local stores are terribly under stocked on most things of this nature. That would be a solution to at least tell me if the amps in the wild acted the same way they do in captivity.
  10. Square


    Apr 9, 2012
    This is a good point. I'll be the first to admit I don't know what to expect. I'm new to Bass and all it's nuance having been a guitar player all these years. I can tell you that I have a 30 watt tube amp (guitar) in the same room and I'm pretty confident the Ampeg wouldn't keep up.
  11. lowfreq33


    Jan 27, 2010
    Endorsing Artist: Genz Benz Amplification
    The fender probably has a relatively high cutoff frequency on the high pass filter to get more perceived volume out of it since it's designed to get the most out of the combo format. The Ampeg is designed to work with a variety of speaker cabs. Could also be one is going into 8 ohms and one into 4, which will make a small difference.
  12. lowfreq33


    Jan 27, 2010
    Endorsing Artist: Genz Benz Amplification
    My bad, just saw it's a Rumble head into a 210. A 210 has more surface area for the drivers than a 115, so depending on the cab design it should be a bit louder.
  13. Square


    Apr 9, 2012
    No you were correct. It is a combo. I did word the OP a little weird. So maybe adding another 15 to the Ampeg would put me in a similar ballpark. That would let the amp use it's max available power I suppose and give the benefit of a second speaker.

    In the end this is loud enough, as is, for anything I will do in the next year or so but I would like to be confident that I can hang with an unmic'ed drummer and a couple of loud guitars.
  14. Actually one 15” speaker has more surface area than two 10” speakers.
  15. tomconway


    Dec 2, 2010
    How can the surface area of two 10inch speakers be smaller than the area of one 15inch speaker? :eyebrow::confused:
  16. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    PF115 has a lot of low end response and the Rumble does not. The tradeoff for that kind of low end response is reduced comparative volume because it takes more wattage to amplify lows than highs or mids. Swap heads around with the cabs and you will find the PF500 has more volume in the Fender cab and the Fender head has less volume in the Ampeg cab. Physics. Can't do a thing about it.
  17. Square


    Apr 9, 2012
    My math shows the surface area of a 15" circle would be smaller than the surface area of two 10 circles. Pi • r² = 113.097" = 15" circle and 157.079" = 2x10" circles.

    Now speakers are cones not circles, but I would need a few more numbers for that... and a lot more concentration.
  18. panamonte


    Dec 12, 2009
    Brighton, UK
    That's all true, but there are some things you could do that might help. Here are my suggestions - some/none/all might be of use:

    1. Roll off the low end on your amp (costs nothing)

    2. Get one of these - [sfx]:Thumpinator (costs a bit more)

    3. Get another PF115 so you've got 500 watts into 4 ohms (costs quite a lot more)

    The thing is that if you're sitting a couple of feet in front of the cab in your bedroom you won't be hearing a lot of the LF that it's pumping out - probably more than you want/need - so rolling off a few dB at 40Hz (option 1) is probably going to make quite a difference.
  19. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Either way it's a moot point. Cone surface area has little bearing on the result. Displacement (T/S spec Vd) does.
    +1. OP, google 'equal loudness curve'. Most combos have cabs that are too small for the drivers within, resulting in a response bump in the midbass, which subjectively makes them sound louder. That's realized at the cost of low end output.
  20. Speaker size matters when it comes to moving air (SPL) - cone surface area.
    # 8” 10” 12” 15” 18”
    1 50 78 113 176 254
    2 100 157 226 353 508
    3 150 235 339 530 763
    4 201 314 452 706 1017
    5 251 392 565 883 1272
    6 301 471 678 1060 1526
    7 351 549 791 1236 1781
    8 402 628 904 1413 2035
    NOTE: All numbers rounded down to the nearest inch.

    Drivers, enclosures, power, etc all are factors but speaker size does matter when it comes to moving air (SPL) and shouldn’t be downplayed. And remember the cab is built around the speaker and not the other way around.