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Need to fix a sound problem: Ever tried running an amp straight into a PA subwoofer?

Discussion in 'Live Sound [BG]' started by PauFerro, Jan 5, 2012.

  1. PauFerro


    Jun 8, 2008
    United States
    I normally play jazz and fusion, and the tone I get is just OK to most players. Well, it's come to a head now that I'm playing in an 80's pop band. They want it to be warm and deep, and they say my bass is too trebly. In performance, they want to be able to "feel the bass in your chest".

    In one group I performed with, they rented a subwoofer for the PA, and it had that effect. So, I have a couple questions:

    1. Why doesn't my SWR Goalith Junior 2X10 and my Peavey Pro Bass 500 amp kick out that really warm and deep bass sound? The SWR Goliath Junior 2X10 is designed to handle frequencies at the low end -- lower than our PA speakers, so why isn't it as good as a subwoofer?

    2. Assuming a subwoofer is the answer, can I just plug my guitar into my Peavey Pro Bass 500, and then run the speaker cable from the amp to a subwoofer when we rehearse without a PA? Would this achieve the effect I'm looking for?

    3. What would be the impact of chaining my SWR Goliath Junior III with a PA subwoofer? The Goliath Junior is 4 ohms and the Amp is 350W into 8 ohms. Subwoofer -- unknown, haven't bought one yet.

    Thanks....this quest for one is a long one!!! Been playing for over 20 years and still not happy.

    I play an Ibanez Soundgear and an SX Jass Bass knock off, as well as a Cort Curbow for most gigs.
  2. I do this sometimes, it will work to add some serious depth for sure but I usually like to be able to control the volume of the subwoofer seperately from the 2x10.

    most 2x10s can handle low frequencies but not at serious volumes. The volume at which a 10" speaker can produce a sound at 120hz is much louder than the volume it can produce sound at Sub Woofer levels like 60Hz. SO even though it is producing those super deep frequencies, its not as loud as the other mid-bass frequesncies so they get drowned out.

    EX: if you have 8 ohms in one cabinet and 4 ohms in the other , the 4ohm cab will be almost twice as loud. Plus make sure your Peavey amp can handle a 2ohm load if you are running more than a 4 ohm load,

    you will probably be better off lookin for a used 15" for on stage though. I've found that a 2x10 paired with 15" will get you the depth you need for on-stage. and small gigs. Plus having a big cabinet with an 18" sub on stage can sound too boomy and sloppy for faster songs. It works OK if all you are playing is R&B and Reggae.
  3. kraigo


    Jun 21, 2007
    Minneapolis, MN
    I guess you shouldn't necessarily believe the specs on bass cabs, even well respected ones like SWR. I don't think super lows are your answer, either. I wish I could come up with a solution that utilized the 2x10, but I can't. I think something like what I settled on, a Genz Benz NeoX 212T or a pair of NeoX 112T's might work better. Modern speakers that have a longer throw than was common when your cab was made. If you're handy or are in a larger metropolitan area, check out the fEarFul stuff at Be seeing you <-That's a fEarFul link. I think USSpeaker.com sells the wood already cut if you'd like to go that route. Any of the above has really good low end extension and should solve your problem.

  4. Hactar


    Sep 25, 2011
    Boulder, CO
    Your 2x10 does not necessarily go lower than a PA sub.
    Also, a sub can drive much higher spls at low frequencies.
    If I am looking at the proper spec sheet, your cab can handle 400W, for a max spl of 105db.
    A large PA sub might get you 135db at lower frequencies, and will make you "feel" those low frequencies much better.

    In response to #2, you certainly "can" run your Pro Bass 500 into a sub, but the mids and highs will be non-existent. Most subs drop off pretty quick past 300Hz or so.
    Your tone will be insanely dark.

    In response to #3, it appears your amp can run down to 2 ohms (500w). You should be fine with either a 4 or 8 ohm sub, although I can't say it will sound good, because the balance between the sub and the 2x10 will be tricky to control.

    Also, if I am speaking of the proper amp, it is not 350W into 8 ohms, but rather:
    200W @ 8 ohms
    350W @ 4 ohms
    500W @ 2 ohms
    Is this correct?

    Hope that helps...
  5. testing1two

    testing1two Gold Supporting Member

    Feb 25, 2009
    Southern California
    There are two things to consider:

    First, if you are setting your EQ so it sounds good standing right in front of the amp, it may sound thin to the rest of the band since your tone changes dramatically with distance.

    Second, the idea of "feeling bass in your chest" is about moving lots of air. As c2thej2theizzo said, your 2x10 cab can produce low frequencies but not at sufficient volume. I used to play a Goliath Jr for many years and I can attest to it's lackluster bottom end, especially when cranked.

    To increase the amount of air being moved you can either add more speakers or replace your existing cab with something that is more efficient and can handle more power. There are many threads on the subject, but the general consensus is that it's better to use a single type of speaker cab and not to mismatch. So instead of getting a PA sub or a 1x15 cab, just add another 2x10 cab.

    If you really want to experience big bottom from a 2x10 cab, ditch the Goliath Jr and find an Eden 210XLT (or better yet, a pair of them).
  6. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009
    running bass guitars into actual subs on stage sounds like indistinct mud and wrecks the PA mix.

    subs get properly crossed over and go on the PA itself, which could carry your bass, too.
  7. PauFerro


    Jun 8, 2008
    United States
    To answer the question above, yes, I'm at 350W @ 4 Ohms with my Peavey ProBass 500 head. My SWR Goliath Junior III is a 4 ohm Cabinet so that's the power I'm getting overall.

    After reading the comments above, it sounds to me that my SWR cabinet is pretty good for the mids and highs (I think that was why I bought it). A sub-woofer is good for the lows.

    So, what about doing one of these?

    1. Get a PA Subwoofer. Run a line out from my amp to the PA mixing board, and run the sub-woofer from the PA system. That way the volume of the sub-woofer can be controlled along with the overall mix of the sound. Second, mike the Goliath Junior cabinet to get the highs and mids through the PA system on their own channel on the PA mixing board.

    2. I have a quarter inch line out, and an XLW line out from my amplifier. Use both of these -- run them into two channels into the mixing board. One channel, I EQ for the lows. The other channel, I EQ for the mids and highs on the mixing board. My Goliath Junior cabinet acts more like a personal monitor and then is largely taken right out of the equation.

    3. What about bi-amping? I always wondered why people did this, but now I understand -- it appears there is no one cabinet that can handle all frequencies really well at all volumes -- so, send the highs and mids to one destination (the SWR cabinet), and the lows to another destination (a sub-woofer) for small gigs. I'm not sure if there are any amps out there that does this anymore. I know the GK 800RB did at one time, but that was 20 years ago.
  8. testing1two

    testing1two Gold Supporting Member

    Feb 25, 2009
    Southern California
    You really only need to use the XLR DI output on your bass head to the mixer and add subs to the PA system. This is the most common setup. A PA system will always benefit from subs allowing things like kick drum and bass guitar to be heard/felt in the audience. Combining a mic and a DI is fantastic but probably overkill in your situation and requires some advanced tools to make sure the two signals are in phase.

    No need to send two direct signals unless you are planning to use separate processing/effects for the lows & highs. The full-range signal from your XLR output will sound great through a decent PA with subs.

    Actually, bi-amping as you describe it is largely unnecessary these days unless you a) want to add processing/effects to the lows & highs separately or b) aren't running through the PA and your amp rig needs to fill a large room.

    So long story short: subs for the PA will give you plenty of low end in the house and a better bass cab will give you plenty of low end on stage.
  9. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009
    right; let go of the "playing bass through your own sub" idea. a bigger cab on stage than a 2x10 will give you a stronger sound on stage, but "chest-thumping" low end needs to come from the PA.

    the best way to get your rig happening without wasting or selling what you have now is to wrangle a second identical 2x10 cab. you'll get the full 500+ watts out of the peavey head at 2&#937;, and the increased speaker area will get you more of everything, including fat low end.
  10. 335guy


    Sep 3, 2011
    I concur. I run the sound for our band from onstage unless we are playing a larger venue with a provided sound company. We use aux fed subs and run the bass player's pre-eg signal into our Soundcraft mixer. And from there to the FOH amps and speakers. The head the bassist uses allows for both pre and post eq, and I recommend pre eq. By aux feeding the subs, I can dial in the exact amount of sub and upper/mid cab for each channel. Typically, only the bass, the kick, maybe a little floor tom and keys go through the subs. This allows the bass player to get the tone and volume right for the stage, and allows the band to get those chest thumping lows ( and clear highs ) by running the bass signal through the FOH cabs. PA systems without subs aren't gonna get ya there. If the band doesn't have subs now, they need to think about getting them. And adding another 2 x 10 to you rig will work quite well to get you more bottom and punch on stage.
  11. Zoa


    Dec 28, 2009
    Just to add something no one has mentioned yet, though it's probably a secondary factor: An Ibanez Soundgear would not be anywhere on my go-to list for "warm and deep" tone.
  12. testing1two pretty much said it all - Forget about adding subs to your rig and add them and a crossover to the PA and let them do their job - get that fat bass sound out to the audience. More than likely you'll feel the residual effect onstage as well, IME a good FOH sub rig means you feel more than enough deep bass sound onstage as well.
  13. Only marginally on topic, but I have gone preamp -> Crown I-Tech -> (2) EAW double 18 subs. It was pretty awesome, perfect should you need to play bass for the loudest dub band in the world. I actually don't.

    Ironically enough it was this goofy purple soundgear thing I've been playing lately. The tone was both warm and deep. and punchy. maybe even phat.
  14. Gearhead17

    Gearhead17 Supporting Member

    May 4, 2006
    Roselle, IL
    An Ibanez Soundgear can achieve a WIDE range of tones - different strings, EQ settings and playing styles could easily manipulate the tone to what you wanted.

    Get an identical 210, stack them vertically and have fun. Don't bother running a sub woofer with your bass rig. On stage, it does nothing, but annoy sound guys while adding a bunch of low end to the stage. If you already have a PA with subs, you will almost always hear and feel those subs booming for the entire show. Under 200hz, bass frequencies generally go every direction imaginable. There is your free low end.....

    In regards to your 210, it is designed to sound good throughout all frequency ranges. A PA sub is 100% dedicated to the 150hz and lower zone, and has a bigger enclosure. It's going to pound you into oblivion long before the 210 ever will.
  15. D1on


    Apr 13, 2011
    Why not get a Goliath?

    Stack the Junior on it for a 6/10.
    Plus you'll have a 2/4/6 option.
  16. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009
    +1, but;

    he would need to re-wire that JR from 4&#937; to 16&#937; to match it properly with the 8&#937; 4x10 and get equal power to all 6 speakers at a 5.3&#937; load, but that's not too hard to do.

    a series/parallel switch or pair of switching jacks on the 2x10 to go from 4&#937; to 16&#937; would be the ticket here; 4&#937; to use it by itself on little gigs, use the 4x10 by itself for most everything, or switch the 2x10 to 16&#937; and use the full 6x10 stack for really loud gigs (or outdoors).
  17. PauFerro


    Jun 8, 2008
    United States
    I have a Goliath Junior III right now at 4 ohms -- do you think I'm taking a chance adding a Goliath Junior IV 2X10 at 4 ohms to the rig? Or do I have to try find another Goliath Junior III used somehwere to match with my current cabinet?
  18. Gearhead17

    Gearhead17 Supporting Member

    May 4, 2006
    Roselle, IL
    Yes, you would be taking a chance. With that setup, the 210 and the 410 would be getting the same amount of power. Therefore the 210 will give up faster than the 410 and you will always be limited by the volume of the 210. If the 210 was 8 ohms and you used it with the 410, they would each get the same amount of power - a true 610 in the end. It would allow both enclosures to get plenty loud at the same time EQUALLY.
  19. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009
    wait, i think he means another 4&#937; 2x10 cab.

    the difference between a 4&#937; 2x10 III and a 4&#937; 2x10 IV can't be all that big, can it?

    if the boxes look close to the same size and shape, i have to think they'll behave close to the same, and the two together would make for a pretty strong 2&#937; stack.
  20. Gearhead17

    Gearhead17 Supporting Member

    May 4, 2006
    Roselle, IL
    Get another Goliath Junior 3 at 4 ohms and you will be good to go.

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