Power amp and PA cab, maybe?

Discussion in 'Amps [BG]' started by Seathal, Jan 23, 2013.


  1. Seathal

    Seathal

    Joined:
    Jan 20, 2011
    I've seen a lot of discussion going on about the head vs pre+power amp issue, and some posts about using PA cabs as bass cabs. But I want to revamp the topic (since the ones talking about cabs are old and don't want to resuscitate them, see if I can sort some things out.

    I plan on getting a digital preamp (Not sure if Line 6, Tech 21, TC Electronic or what, but that's not the issue here) and hook it up to a stereo PA power amp and some cab.

    I want to keep the costs minimal, I found a Yamaha AX15 (15" cone + 1" twitter, 400WRMS, passive PA speaker) on sale for 120€ (160$ aprox.). Do you think it is suitable to hook this and a sufficient power amp for on-stage bass monitoring? I'm all for flatness and fidelity (even if it's not high-fi) and practicity, don't care for big brands or brand "tones", just want a flat response like the I would get from my studio monitors, not a colored vintage or modern amp&cab sound. Also can't afford expensive PA setups or huge systems, limited budged to around 400€, less if possible).

    What do you all think?
  2. CL400Peavey

    CL400Peavey Supporting Member

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    The problem is that is just a PA main, not a sub. Depending on what your tonal goals are that could work, but I wouldnt expect a whole lot of true bass out of that cab.

    To make the whole mini PA thing work you need to have something for the mids/upper end, a sub woofer, a cross over to split the signal appropriately to each channel, and a stereo power amp to power both channels. This usually negates the cost/size/convenience/tonal benefit of such a rig, which is why bass amps are still preferred.

    The upside is that there are some bass cabs that do most of that in one unit. They combine a LF driver with a mid driver/horn all in one box. They have a passive internal cross over. All you have to do is send them a single channel signal from an amp and they are good to go. I would check out:

    Barefaced Bass
    fEARful
    fEARless/greenboy cabs
    Baer audio
    Audiokinesis Thunderchild
    Bill FitzMaurice

    I run such a rig, my signal chain is something like this:

    Aguilar Tone Hammer -> ART Pro Channel II -> fDeck HPF-3 -> Peavey IPR 1600 - fEARful 1515/66/1.

    I really like the clarity, and low end I get with this system. Or when I want some grit it also handles effects very well.
  3. Seathal

    Seathal

    Joined:
    Jan 20, 2011
    That was some useful input. Thanks! But all of those brands you mentioned aren't easily available in Europe. Already checked fEARful, but prices are prohibitive. My problems would easily be solved with a powered bass cab, but I don't think there's any within my price range. Which makes me wonder why since they should be cheaper to produce than combos (taking away the Pre, EQ, FX and all that from the equation). Found out that the cheapest solution might be getting a power stereo amp, bridge it, and connect a 8ohm bass cab that can handle it. With the possibility of adding another cab later on and having a small stereo setup.
  4. CL400Peavey

    CL400Peavey Supporting Member

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    You dont have to bridge the amp to make it work, if it is a SS amp it is safe running only one channel.

    The beautiful thing about the fEARfuls is that the plans are free, you could build one yourself if you had the tools. If that is outside of your comfort zone there is a Authorized Builder in the UK that is selling flat packs. All the wood comes pre cut, you just have to do the final assembly.

    Barefaced bass is also in the UK. You would be amazed the amount of volume you can get out of something like the Big Baby.
  5. steve_rolfeca

    steve_rolfeca Gold Supporting Member

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    I'm a full-range guy myself, been using two and three way cabs since the mid '90's.

    The trouble is, with your budget, you can't afford anything good, and less expensive PA cabinets tend to sacrifice the low end in favour of preserving the all-important midrange.

    If you absolutely can't wait while you save up for something more suitable, you'll get a better bang for your buck from a regular bass cab.

    Either way, do yourself a favour, and buy used.
  6. Seathal

    Seathal

    Joined:
    Jan 20, 2011
    Thanks for all the useful input and oppinions!

    I'm starting to see that, within my price range, I'll end up with a crappy, over-complex amping system, as you said.

    Spreading the research I found a used Yamah BBT head with a matching 1x15/1x1 cab for 350 shipped. Maybe will end up getting that. I've been told they are quite flat and pure sounding and that they have versatile, programmable and can be hooked up via MIDI. Maybe the pre-amp redundancy will be worth with such features at such a low price. Looks that's what I'm looking for.
  7. chucko58

    chucko58 Supporting Member

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    I paid for all my gear myself. Well, me and MasterCard.
    Many bassists, myself included, would have a hard time using a 2-way PA cab effectively. There would be too little mid-bass (80-160 Hz) and too much treble (> 2 KHz).

    I am not a fan of the typical 2-way bass cabs with a woofer or two and a horn tweeter. The midrange is left uncovered, and you've got that high end that IMHO is just noise without the mids to support it.
  8. seamonkey

    seamonkey

    Joined:
    Aug 6, 2004
    No problem using a PA cab.
    Everything equalizes if you have too much of some frequencies.
    Most are designed to be fairly flat, so it's not that they don't have too much of some frequencies, it's that they don't scoop it out by default.

    You should though, look for PA with charts. Probably out of your price range but look charts
    http://cn.jblpro.com/BackOffice/ProductAttachments/JBL_PRX415M.v3.pdf

    There's a sub also in this model line that you can compare the chart of it to that of these tops. It's simpler than it may seem. Find an ear training site and learn what the different frequencies sound like that are on the charts.

    Once you know what one chart sounds like, you can reference and compare what other charts would sound like. The PA world is rich in published measurements, take advantage of them.
  9. two fingers

    two fingers Loud Mouth Know It All Blowhard Gold Supporting Member

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    Feb 7, 2005
    What your are talking about is a speaker on a stick (or "tops"). There's a reason why no band runs just those if they want bass out front. It's because they aren't DESIGNED to produce those frequencies at any decent volume level. Bands use SUBS along with the tops if they want to produce bass out front. It's no different for you. The laws of physics don't stop at your bass rig. It still wont produce a really good low end with any volume whatsoever. And the watt rating of the cab means nothing. If the CAB and DRIVER are not TUNED or DESIGNED to produce good bass then it could be a 4 BILLION watt cab and still sound like crap.
  10. Seathal

    Seathal

    Joined:
    Jan 20, 2011
    Seeing as the growing trend for many bass players (specially when playing on larger venues) is to have a DI out and monitoring from monitor mixing board instead of hacing a monster-rig behind (which I respect and admire but do not share) I wondered if I could reproduce that in a cheap, smaller scale.

    Thanks to the input here and some research I discovered that a bass amp and a bass cab are basically the same that some stereo pro amps combined with full range or sub cabs, but differ in some key ways. When you're in the budget (I'm talking under 1000€ for amp'ing yourselg) your best bet is surely a dedicated bass amp and cab, or a combo, since the PA stuff at that price range is usually not hihg-quality and focused on reproducing vocal and keyboard's mid range.

    If I had 2000 bucks available I'd sure try out such a kind of system though, but since I don't I'll stick to traditional bassist options. I think i found a pretty flat and hi-fi sounding cab and amp, and that will do for now, maybe in a future I'll bi amp or even try to mini-pa myself, though at that stage maybe I don't need monitoring of my own anymore and will be running straight to the mixing board and the PA or with in-ear systems, we'll see.

    Conclusion: It is possible but to do it properly, even at a small scale, it's costier than a "traditional" bass rigs. It's such a shame though that nobody seems to offer power-amped cabs at "budget" prices to combine with pre's, which I think would be an amazing way to amp yourself cheaply and effectively.

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