OK -why is it dual cabs always sound fuller

Discussion in 'Amps and Cabs [BG]' started by Oren Hudson, Jul 8, 2008.

  1. Oren Hudson

    Oren Hudson

    Dec 25, 2007
    Gastonia, NC
    Over my many years of thumpin' on the bass, I've played through bunches of amps - both combos and seperates. It never fails my ears that, no matter what cab I'm using - one or multiple speakers - always sounds bigger and fuller when another cab is added - again, no matter the number of speakers in either cab. I know that generally, more power is generated, but I'm not talking about volume or loudness, just the bigger fuller sound. I've just completed semi-restoring a late 70s early 80s Dean Markley 1-15 bass cab with an Eminence alnico unknown wattage (probably 100) speaker. After doing some repairs, replacements and joint reglueing, I was putting it through the paces and it sounded actually better than I thought it would. I'm also working on a complete resto on an Accoustic 301 cab (1-18 CV 300 watt speaker) and so it's standing there near where I'm playing and I decide to hook it up too. Once again, I was amazed at the fuller bigger sound the 2 of them together made verses one or the other individually. Just one more instance of this phenom occuring. Any other of you TBers experience this? I'm sure there are explanations, but it's just IMO odd that, for example, you take a 1-15 cab and add another 1-15 cab, and you get the fuller bigger sound than with 1 cab with 2-15s, with everything else being equal. Comments.:cool:
  2. Rick Auricchio

    Rick Auricchio Registered Bass Offender Supporting Member

    Many commercial cabs are "overstuffed," where the manufacturer is cramming in drivers without really enlarging the cab much.

    So a 1-15 will probably have more internal volume than half of a 215 cab. Thus you get two better 115 cabs instead of a single mediocre 215.
  3. bongomania

    bongomania Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    There is a factor called "coupling", when two speaker cabs are stacked together, or a speaker cab is directly on a stage floor. I'm not a cab expert to explain it myself, but if you look up "coupling" or "acoustic coupling" it should explain most of what you're hearing. Also I would say on average two separate 1x15 cabs together will be physically much bigger in total cubic inches than a 2x15 from the same product line.
  4. Are you sure? Have you measured to make sure you're not playing louder through the two?

    My money is on the differences in frequency response combining to give a fuller spectrum. Not necessarily flatter, but probably fewer gaps.
  5. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    The technical term is Mutual Coupling, the result is a 6dB increase in output with two identical cabs.
    With cabs that are not identical there can be as much destructive interference between them as constructive coupling. What you'll get is totally unpredictable.
  6. What's the cause for that?
  7. Bassmec


    May 9, 2008
    Ipswich UK
    Proprietor Springvale Studios
    I think its due to minute differences in phase between different speakers
    all at various frequencies and harmonics.
    I still like the sound of some 15's mixed with some 10's though.
    They can fill in for each other quite well sometimes.
  8. Oren Hudson

    Oren Hudson

    Dec 25, 2007
    Gastonia, NC
    Interesting stuff so far guys. I'll add a little more to my original post. In response to lemur821> yes, it can be louder with the 2 cabs, but in all of my experiences, I haven't crank it just because I can, but that fullness is noticable from about mid volume on up. Also, a little clarification. In most instances in my experiences, the cabs are not stacked, but range from being side by side to my favorite positioning, one cab on each side of the drums. Although I find the phenom to be occuring in nearly any configeration, the particular case I described in the first post, the Dean Markley cab is actually about 8 feet from the Acoustic cab and they are almost facing each other.:cool:
  9. pedro


    Apr 5, 2000
    Madison, WI.
    Bill are you agreeing then that 2 1x15 are louder than 1 2x15?
  10. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Not at all. But two identical 1x15s will be 6dB louder than one, driven by the same amp at the same level, provided they are placed within 1/4 wavelength of each other. That means less than three feet apart.
    Doing so their outputs will cancel each other out at many frequencies, and depending on where the listener is two won't be as loud as one.
  11. I didn't mean to suggest that you were cranking it, but it's possible that you're unintentionally producing a little bit more sound with the two cabs, and that's coloring your perception.