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Will a DBX 120 break my current rig?

Discussion in 'Amps and Cabs [BG]' started by butterbean, Feb 18, 2008.

  1. butterbean


    Mar 6, 2007
    I have been looking around the forum trying to get answers to a couple of questions but haven't had any luck.

    Basically I am trying to get some more dubby, reggae vibes out of my rig and this is how I plan on doing it.

    I have a SWR 400s (150 w @ 8 ohms per channel) and I plan on bi-amping it and pumping the low end frequencies through an SWR Big Ben 118 and the highs through an SWR Goliath 410.

    I am also going to run a dbx 120a on just the lows so they would be going to the Big Ben.

    Will this work or will I be apt to break my rig?

    If this setup will break my rig what can I do/what would you recommend?

    Also would this work with a Son of Bertha running the lows.

    Here are the specs for both cabs:
    Impedance (Ohms) 8 Ohms
    Power Handling 800 Watts RMS
    Frequency Response 105 dB SPL @ 1W1M (-3dB @ 40Hz and 15KHz)
    SPL 105 dB SPL @ 1W1M (-3dB @ 40Hz and 15KHz)

    Big Ben
    Impedance (Ohms) 8 Ohms
    Power Handling 400 Watts RMS
    Frequency Response 100 dB SPL @ 2W1M (-6dB @ 25Hz and 3khz)
  2. Willem


    Dec 26, 2005
    the dbx is a compressor right?
    it can not hurt your speaker... you can though.
  3. butterbean


    Mar 6, 2007

    You are thinking of the 160 compressor.
    The 120a is a subharmonic synth which produces a synthesized waveform in the 25-56 hz range (an octave below the note you strike).

    This can be damaging to cabs if they are not tuned to those very low freqs/have enough power from what I know.
  4. koobie


    Jul 11, 2007
    Portland OR
    That's a lot of trouble to go through for a sub-octave tone generator. The tracking in those circuits are not 100% consistent, meaning they'll double some notes very well and some not so well. Make sure you try a 120 before you buy a second cab, etc. And fwiw, I don't think I've ever heard a reggae bass player use one of those, but I tend to prefer the more old-school reggae.
  5. figuredbass

    figuredbass Supporting Member

    Jul 11, 2007
    NYC vicinity
    I think you should be OK as long as you heed the power ratings of your amp and cabinets. The main thing to be careful of is excessive bass boost EQ. When you turn a bass control up it generally boosts inversely proportional to the frequency, meaning that there is considerably more boost in the lowest frequencies. As these lowest frequencies are not as audible or reproduced by cabinets as well, you can exceed power ratings without even realising it. So just be careful!
  6. I own the 120a sub-synth. Yes, it can definitely trash your woofer. Unlike an electric bass, the 120a generates a full power signal at 26 Hz.

    Very few commercial cabs are designed to handle the amount of cone excursion created by the 120a. You will have to listen for farting, and back off when it occurs.

    When I ran the 120a in my rig, I had two RFR-2215 subs tuned at 31 Hz. These are high quality, very low efficiency subs with long Xmax. They are rated at 1,000w and don't make very much noise, but they go down very low.

    If you can rent or borrow the 120a, do so, and get it out of your system. Mine sits in a box in the garage, and it should go out on eBay.
  7. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics

    A 120A into a 150 watt amp is nothing but trouble waiting to happen, IMHO.
  8. butterbean


    Mar 6, 2007
    Besides passingwind nobody has answered the question here.

    I have asked passingwind what he thinks I need to do to get this setup up and running.

    If anyone agrees with him that a 120a into a 150watt amp is asking for trouble please elaborate and also let me know how to remedy the situation (whether it is adding a poweramp or whatever. Please note I have been thinking about picking up a WT800 that would give me 300 watts per channel at 8 ohms if that helps!).

    Thanks all!
  9. ihixulu

    ihixulu Supporting Member

    Mar 31, 2000
    South Shore MA
    Here's what you need to have it not sound like poo at a reasonable volume: Take the hi out of the 400s crossover and feed it back to the mono in of the head and output that to the Goliath. Take the low out to the dbx 120, feed that into a 1000 watt power amplifier and feed that to the Big Ben, all the while listening for any signs of stress in the speaker. It'll sound fat and probably more than a bit artificial. Just about every reggae bass player who has a fat tone is going through just a cable and an amp (and a DI).

    You say you are after a dubby reggae sound.... how are you eq'ing your head? I run an SM400 into a Goliath Sr. and can get a dubby tone rather easily. What bass are you using? Fill out your profile so that we can get a better sense of what you might be up against.
  10. butterbean


    Mar 6, 2007
    Thanks Man!

    Sorry about not filling out my profile.

    I know what you mean about the DI. It is that tone I want while at home or in rehearsal. I love the way my shizzle sounds when I DI into a huge sub group and I am just trying to replicate that in other situations.
  11. ihixulu

    ihixulu Supporting Member

    Mar 31, 2000
    South Shore MA
    Now that I think about it, don't even bother with the crossover. (Amazing what a cup of coffee will do) Run the Goliath full range, and take the effect out to the 120 -> power amp -> Big Ben. Bi-amping i this situation will simply rob you of useful power in the low end. I.e. there is no reason not to run the Goliath full range, considering it does have a decent amount of low end on its own.
  12. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    Apologies for the terse reply yesterday. I was out the door for a rehearsal I was kind of dreading.

    Anyhow, I have used the 120A and the variant in the DriveRack quite a bit. Personally, I'd recommend a bare minimum of 600-800 watts RMS for your Big Ben. Then use only maybe 8-12% subharmonic content, definitely no more than 15-20% tops in my experience. With great power comes great responsibility, so be very careful when you start using the 120A. We creased a few 18" cones in our PA in only a few months when the other sound guy inexplicably (hah!) cranked things up over 20%.

    That said, I've mixed tons of reggae bands, and I've very rarely seen the bassist using a subharmonic generator in a stage rig. IMHO it probably belongs in the PA rack if anywhere, in most cases. You could ping Burning Skies for some real knowledge of authentic reggae style gear and technique. I do see these things in jam bands and the occasional funk band, so maybe I just haven't been paying enough attention at the reggae shows.

    Good luck, and have fun...:cool:

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