Bass Cab Question

Discussion in 'Amps and Cabs [BG]' started by Coin Return, Aug 21, 2003.

  1. i tried bi-amping it the correct way with the 1x15 on the 300w low channel, and the 4x10 on the 100w high channel, it sounds alright in my room at a loud volume, but i still need to try it with a band in order to see if it really will work.

    trust me bob, i want to get ampegs, or SWRs or something higher quality than what i've got, but i've been trying to sell these for a while but nobody's in the market for them. suckes doesn't it?
  2. D.A.R.K.


    Aug 20, 2003
    have you checked to make sure your cabs are in phase? - phase cancellation can kill your sound...your rig should be pretty darn loud....
  3. lo-freq

    lo-freq aka UFO

    Jan 19, 2003
    DFW, Texas
    It sounds like you already have some issues worked out.

    Good luck and let me know how it goes playing with the band.
  4. BruceWane


    Oct 31, 2002
    Houston, TX
    1)RMS rating and efficiency are two separate things.

    RMS is the maximum average power level that a speaker will handle. With any quality speaker, RMS is tested by using a full range tone that includes some transient peaks of +6db. In plain english, this means that a speaker that is rated at 300 watts RMS can handle a steady 300 watt signal with intermittent peaks of 1200 watts. That's why it's OK to have quite a bit more power in the amplifier than the RMS rating of a speaker - the amp needs the headroom to keep from distorting on those peaks.

    Efficiency is how much sound you get per watt. Think of the efficiency rating as a starting point - it is how many decibels you get from one watt into a particular speaker, measured at 1 meter. For every 3db increase in volume, you will have to double the wattage driving that speaker. Let's look at a typical single 10" bass speaker, something like what Avatar uses........

    1 watt = 96db
    2 watts = 99db
    4 watts = 102db
    8 watts = 105db
    16 watts = 108db
    32 watts = 111db
    64 watts = 114db
    128 watts = 117db
    256 watts = 120db
    512 watts = 123db
    1024 watts = 126db
    ........and so on..........

    Things to keep in mind when looking at efficiency - realize that this is measured at one meter, and that sound levels dissipate pretty quickly. 125db at one meter gets you around 114 db at twenty feet. Also keep in mind the wattage limit of the speaker (RMS)....You may see a speaker that is very efficient, say 99db, but you have to keep in mind that if it only handles 100 watts, you're only going to get 120db maximum out of it. Also keep in mind that efficiency is pretty much directly related to how well a speaker reproduces low frequencies. Lotsa speakers that get loud, but they don't go very low, and lotsa speakers that go low, but they don't get loud enough to use in a rock band. It's physics, and you can't really get around it.

    Basically, high RMS is a good thing, and high efficiency is a good thing. However, because of the way a speaker is built, at some point to get more of one you have to give up the other. High RMS is achieved by having a really heavy duty voice coil that won't melt under a lot of heat - but the sturdier the voice coil, the more it the speaker has more weight to move, which makes it - you guessed it - less efficient. High efficiency and high RMS aren't completely mutually exclusive, you just have to strike a balance between them.

    So you can get your required volume either by pushing more wattage into less efficient speakers, or by pushing less wattage into more efficient speakers. And you have to find a speaker that does low frequencies to the degree that serves your purpose as well - which means you will be trading off efficiency for tone to some degree - and that degree is entirely up to your own ears. It's all a balancing act.

    By the way, running both those cabs from the 300 watt section of the 800RB will work - but you won't have any control over the volume of the two individual cabs. You won't be able to balance them. Hopefully, they'll sound even together........
  5. Thanks Bruce!

    I think I got most of that. So with all of that said...........

    Avatar 4-10's and 1-15 OR

    Ampeg 4-10's and 1-15 OR

    are 2-10's more effecient?
  6. KeithPas


    May 16, 2000
    I would get an Avatar 1/15 and 2/10 cabinets.
  7. lo-freq

    lo-freq aka UFO

    Jan 19, 2003
    DFW, Texas
    (If I understand what you're asking correctly.)
    Generally, no.

    If you're talking two cabs using the same drivers, but different numbers of drivers.
    Surface area helps efficiency.
    Usually, doubling the surface area of a given set of drivers yeilds a 2 to 3dB increase in efficiency. So between a 1x10 cab and a 2x10 cab, the 2x10 cab will be approximately 2 to 3dB more efficient. The difference between a 2x10 and 4x10 would be 2 or 3dB more efficient for the 4x10 (given same drivers, same basic cab design, & same cab resonant frequency).
  8. I have to tell you guys that the last week or so has certainly been an adventure! ALMOST makes me want to play bass :D :p :meh: ;)
  9. BruceWane


    Oct 31, 2002
    Houston, TX
    Ampeg has a few different models, but generally speaking most Ampeg cabs are going to have a more bass heavy tone than the Avatars. Avatar uses off-the-shelf Eminence speakers that are fairly generic; they're designed to be used in PA's, or bass rigs, or monitors......where Ampeg has their drivers custom built to their specs for use specifically in a bass cab. If you've got some Ampeg cabs available used from a friend at around the same price as the Avatars, I'd go with Ampeg.

    As far as 2x10 versus 4x10 with a 1x15, there's no harm in using a 4x10 other than the extra weight. Using the same speakers, a 4x10 will be 3db more efficient than a 2x10. If you've got a good deal available on a 4x10, I'd get it. If not, the 2x10 is probably a closer match for the 1x15 because of the efficiency of the cabs. A typical 1x15 is going to be around 96~97db @1 watt, a 2x10 around 100db, and a 4x10 around 103db. So if you are hooking these up full range to a single amp, a 4x10 is going to be quite a bit louder than a 1x15. If you're either biamping or using two separate amps, you can compensate by turning the 4x10 down a little - but then why carry the extra size & weight when a 2x10 would do just as well?
  10. We're talking about an Ampeg SVT 4-10E used in nice shape (Not Mint/ a few scuffs in the tolex) for $270.00. My son wants to take it.
  11. BruceWane


    Oct 31, 2002
    Houston, TX
    Sounds like a pretty good deal to me. I think going rate for that cab used is $350~$400. Who cares about a few scuffs - it's gonna get more anyway. As long as it's structurally sound, no funny sounding speakers, etc. I'd go for it.
  12. Primary

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    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

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