Bass Cab Question

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

  1. hanales


    Jul 12, 2003
    Youngstown, OH
  2. I guess you missed the part about NOT biamping. :meh:
  3. redneck2wild


    Nov 27, 2002
    Memphis, TN
    The crossover on the head goes down to 100hz in the farmost left position. This is much lower than what most horns can handle.

    Since the 4x10 can handle frequencies this low (and lower) and Coin Return is already biamping, this is the setting I would use if I were driving 2 cabinets.

    The Low channel can only go down to a 4ohm load - the 1x15 is a 4ohm cabinet.
    The 1x15 and 4x10 can not both run off the Low channel - 2.67ohms.

    The High channel can go down only to an 8ohm load - the 4x10 is a 8ohm cabinet.

    So in my opinion, the best setup for Coin Return to get the most out of what he has without spending any additional cash would be to biamp (which is the only way he can run both cabs currently).
  4. i think pete is onto something.... however, i don't think i use the bi-amp feature completely, in the back side of my amp, there is 3 imputs for speakers, 2 for the 300w low end, and one 100w for the high end, i don't use the 100w high end because it gives off a lot of treble(probably why it's meant for the horn), this whole time, i've just been using the two low end imput jacks for the 4x10 and the 1x15. aw ****
  5. lo-freq

    lo-freq aka UFO

    Jan 19, 2003
    DFW, Texas
    That's endangering your amp with too low of an impedence load.

    You should be able to set the X-over to around 200Hz and if need be, cut the treble using the amp's tone controls.

    I would give it a try.
  6. OR try the full range setting on BOTH amp sections. You don't have to biamp that 800RB.
  7. Petebass


    Dec 22, 2002
    QLD Australia
    that's what I reckon, but not with the current cabs. That 4 ohm 15" is complicating things. Maybe sell it and replace it with an 8 ohm 15". That will solve all your problems.
  8. "That 4 ohm 15" is complicating things."

    You really think so?

    300 watts to 1-15' at 4 OHM Full Range

    100 watts to 4-10's at 8 OHM Full Range

    What's the problem? I don't understand. Remember, I'm just a guitarist :rolleyes:
  9. Petebass


    Dec 22, 2002
    QLD Australia
    The problem is that it creates a 2.67 Ohm load and that amp isn't designed to go below 4 Ohms.
  10. You obviously don't know this amp. There are two independent amps in the GK 800RB.

    POWER <1% THD


    [email protected], [email protected], 1kHz.
    [email protected], 1kHz.
    1/4" jack, 10dB Pad and Volume.
    Low cut, Contour and High Boost Switches.
    Bass Specific Series Four Band Active.
    Footswitchable Boost, Switchable Cross-Over,
    and High and Low Masters.
    Send and Return.
    Two 1/4" jacks for 300W Amp and One 1/4" jack for 100W Amp.
    23 lbs.
    17.5"W x 5.25"H x 9.5"D

    That is the specs from the GK website. My son's manual also states the the 100 watt section will put out [email protected] You can use any combinations within these parameters. I've been desparately trying to make this point. Coin Return is plugging both cabs into the 300 section and that will give him an impedance lower than 4ohm which the manual warns against. Plugging one 4 ohm load into the 300 watt section will produce 300 watts WHILE plugging an 8ohm load into the 100 watt section will produce 100 watts. He will get the FULL potential of this amp with his cabs! More so than if he used an 8 ohm load in each amp section. The fron controls of the 800RB has a swith to go from biamp tp FULL RANGE. The GK website goes on to say:

    Traditional Bi-Amp:
    Traditional bi-amping uses a crossover network to split the full-range signal into two parts, the low frequency side and the high frequency side, which are sent to two individual power amps to amplify the low and high frequencies separately. In a Traditional Bi-amp rig, most people use a large cabinet such as a 1x15 for their "lows" and a smaller cab like a 2x10 for their "highs". The 800RB's Traditional Bi-amp capability utilizes two power amps in one package, which can be used full range or in bi-amp mode to get better separation and clarity when using two or more cabinets with different size speaker configurations.

    which can be used full range or in bi-amp mode
  11. Petebass


    Dec 22, 2002
    QLD Australia
    Maybe I am missing something here. But my understanding of the 100w amp is that it can't be run full range. I was looking to buy a GK head a few years ago and remember reading that when the bi-amp mode is disengaged, the smaller amp sits idle. As always I could be wrong........
  12. I think you're missing something here.

    The 800RB's Traditional Bi-amp capability utilizes two power amps in one package, which can be used full range or in bi-amp mode.
  13. lo-freq

    lo-freq aka UFO

    Jan 19, 2003
    DFW, Texas
    I think this should be (the second option is probably what you meant):

    300 watts to 1-15' at 4 OHM Full Range

    or in Biamp mode
    300 watts to 1-15' at 4 OHM Low Chnl.
    100 watts to 4-10's at 8 OHM High Chnl.

    I think that BoB/335 meant bi-amp instead of full range.

    With biamp mode, the current impedences of the two cabs are optimum for the amp instead of being a problem.

    Therefore it makes sense to take advantage of that (unless he decides to get different cabs or a different head).

    What's the problem?

    The original problem was he was getting breakup through his 1x15 when trying to get sufficient volume with his band.

    Since he's playing a 4 string, if he lowers the X-over point until the 1x15 is no longer breaking-up, I suspect that all will be fine.

    As you lower the X-over point, you are asking the 1x15 to do less and less work (output fewer acoustic watts) and asking the 2x10 to carry more of the acoustic load. Since stuff above 60Hz makes much less of a demand on a speaker system, the 2x10 should be fine.

    If fact, I would suggest as a starting point, you crank the master volume all the way up and set the X-over as low as it will go. Then make whatever adjustments give you the most balanced sound without breakup (feel free to cut the treble to smooth out the 2x10 output).
  14. i would, believe me. i've been trying to sell both cabs, but nobody wants anything made by carvin. sucks doesn't it?
  15. Petebass


    Dec 22, 2002
    QLD Australia
    hmmm I don't know....... I'm reading comments like these and thinking he didn't mean to say Bi-Amp at all:-

    "OR try the full range setting on BOTH amp sections. You don't have to biamp that 800RB"

    "300 watts to 1-15' at 4 OHM Full Range, 100 watts to 4-10's at 8 OHM Full Range "

    "I guess you missed the part about NOT biamping".

    All I'm trying to say is that IF you choose to run that amp in Full range mode, the 300w amp takes the entire load and the 100w does nothing. I remember it being a sticky point when I was thinking about buying one. Where's Daniel Elliot, he works for GK, he'd know for sure? As always I'm happy to admit I'm wrong when it's proved I am wrong..........
  16. lo-freq

    lo-freq aka UFO

    Jan 19, 2003
    DFW, Texas
    Okie Dokie. My bad.
  17. OK EVERYONE! Listen up!!!

    I hope this doesn't come off sounding in a bad way. I don't know how to make melf any clearer than I have. Maybe guiter players simply are not on the same wavelenghth as bass players. BUT I'll try this ONE MORE TIME!

    The 100 watt section of a GK 800RB DOES NOT only work when in bi-amp mode. If fact, if you want, you can even use ONLY the 100 watt section at FULL RANGE if you so choose.

    Coin Return,
    I believe your problem is that you are running an 8ohm and 4ohm load TOGETHER in the 300 watt section of the 800RB. Try running the 1-15" alone in the 300 watt section (a full 300 watts @4ohm) and the 4-10's in the 100 watt section (a full 100 watts @8ohm).


    Be sure to come back here and report your findings. You will have the correct impedance to both sections of your amp. Depending on the efficiency of your 4-10's will determine if 100 watts is enough to power a 4-10 cabinet. However you WILL have the correct impedance and will NOT damage your amp.

    Of course I could be wrong :rolleyes:

    BUT I don't think so.
  18. btw I think I forgot to mention the bassist I saw on Saturday night playing with a GK800RB. He seems to agree with my assessment. He was using a 2-10 Goliath III 8ohm cab on the 300 watt section (which he agreed was only giving him 200 watts @8ohm) and a 1-10 cab facing diagonally across the bands path (so the band could here the bass better) which was an 8ohm cab @ 100 watts.

  19. i suggest better cabs, carvin dont make very good bass cabs unfortunetly.
  20. Here's what we decided. (Remember this is for my almost 16 year old son)

    We thought MAYBE we would go for the Avatars. A lot of good opinions on them. MY concern was since they have such a high wattage rating the 800RB might be underpowered. I don't understand, still, how to judge effiency of a speaker but it seems to me that a speaker rated at a higher RMS rating would need a higher minimum power supply. We were looking at the 2-10's and 1-15 both at 8ohm on the 300 watt section.

    So my friend whos's an avid Ampeg fan, tells me that he has an extra 4-10 cab (400 watts RMS @8ohm) for sale. It's here on loan and we will probably take that and look for a Ampeg 1-15 (200 watts RMS @8ohm) I personally think that these cabinets will be a good match-up for the 800RB. They will be operated TOGETHER on the 300 watt section @4ohm. I would hope at some time in the future for a CHEAP 2-10 that he can run off the 100 watt section (ALL AT FULL RANGE. No BI-AMPING!)and maybe place that on the other side of the drummer. Ampeg is supposed to be a good quality cabinet. I heard my son already through this 4-10 with a 1-15 through except with my friend's Ampeg SVT pro3 and I thought he sounded awesome in a live playing band situation.

    Hope that helps!
  21. Primary

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