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Extension cab advice needed

Discussion in 'Amps, Mics & Pickups [DB]' started by Chris Fitzgerald, Feb 10, 2001.


  1. Chris Fitzgerald

    Chris Fitzgerald Student of Life Staff Member Administrator

    Oct 19, 2000
    Louisville, KY
    I'm currently using an SWR Baby Blue amp for all DB gigs. On most gigs, it is fine by itself, but there are one or two rooms in town that I play in fairly regularly (including my weekly trio coffeehouse gig) where I have to push the amp to the point where it starts to sound a little "hot" and muddy. When I roll the bass back to compensate, the tone gets too thin. Last week on one of these gigs, the room was packed and I was bitching about the sound I was(n't) getting, so the keyboard player let me plug in this little P.A. speaker he had in his van as an extension cab.

    It was a tiny little speaker, just 1x10 with a piezo horn, and I think the speaker itself is an Eminence (sp?). It's a locally made speaker from a guy who runs a studio in town. Anyway, with the extension cabinet added, I can't say that I got a lot more volume, but I got a lot more sound, if that makes any sense. It sounded much warmer and richer at the same volume level it had previously sounded crappy at. It would be nice to have the option of having a small extension cab for gigs like this, when I know it's gonna be loud.

    My question is, I'm assuming that by running the amp with the extension cab, I'm running at 2ohms instead of 4ohms. Is this right? Does this harm the amp head in any way by making it run hotter? If it doesn't, then why doesn't the manufacturer just wire the existing cab for 2ohms and get the added "power" right off the bat? Also, I can get one of those little speaker cabs for about $150 in either 1x8 or 1x10, both with the piezo. Both also come in wedge monitor shapes. Which sounds like the best option? Or should I be looking for a dedicated bass cab?

    P.S. - these things are as small as they could possibly be and seem to weigh less than 10 lbs, which I really, really like.

    Thanks,
    Chris
     
  2. What's with the bold face?

    Anyway, this is where (all hail) Bob Gollihur excels. Shoot him an e-mail if he doesn't come on board. I think the resistance halves, rather than doubles, but what do I know? My specialty is computers.
     

  3. Chris, it sounds like you want to run an extension setup similar to the Contra with an extension speaker. What is the ohmage of the extended cab, 4 or 8? The SWR can handle a 2 OHM load ( according to the specs). The reason that the manufacturer doesn't wire it to run at 2 ohms right off the bat is because 1) I have never seen a 2 ohm speaker, and I am sure there is good reason for this, 2)if you tried to plug in an extension speaker, it would fry it ( the amp or the speaker)in about 5 minutes.The simplest equation for ohmage is this: 4ohm X 4ohm=2 ohm ,8o x 8o=4 ohm,
    8o x 4o= 2.67 ohm. And if you're only going to get 1 extension speaker, I recommend the 10".
    I also think the wedge shape is a good idea (a la the hartke "kickback". I have heard from some techs that running your amp at 2 ohms, is possible, but not reccomended as ohms are not a constant thing, there are spikes and surges, depending on where you are playing.
    But, I also want to see what Bob has to say about it.
     
  4. Chris Fitzgerald

    Chris Fitzgerald Student of Life Staff Member Administrator

    Oct 19, 2000
    Louisville, KY
    Really? I thought you were primarily a bassist. May I add that I was very impressed with your recent computer work on the "tritone sub" thread. Even though it wasn't my style, as you know.

    Thanks guys, I will indeed wait for Bob's arrival. He straightened me out on the ohm thing (at least, I THINK he did...) about 6 weeks ago, but he probably knows more about the extension cab issue than most of us. It's not a huge hurry, but I do have some cash lying around & would hate to spend it on something nonessential like groceries & the like...
     
  5. AlexFeldman

    AlexFeldman

    Jun 18, 2000
    Chicago, IL
    Chris, you might wanna check out Raezer's Edge http://www.raezersedge.com. Rich Raezer's makes some of the best bass cabs (10" and 12") on the market. They get a huge sound for their size, and they're very portable. I own a 12, if you have any questions about that it.
     

  6. I have also heard good things about these speakers, but at $400 for a 10, and $525 for a 12, that's quite a jump in price from the $150 one Chris was talking about getting.
     
  7. AlexFeldman

    AlexFeldman

    Jun 18, 2000
    Chicago, IL
    Very true... if the cheaper speaker gets the job done, then it's probably what he needs. The Raezer's Edge cabs are so expensive because Rich builds all of them to order, and as far as I know he is his only employee aside from his son.

    OTOH, I doubt the owners of these cabs would ever consider buying another cab.
     
  8. Chris Fitzgerald

    Chris Fitzgerald Student of Life Staff Member Administrator

    Oct 19, 2000
    Louisville, KY
    Reedo,
    you were reading my mind. That's a lotta bread for a 1x10. A lot of people swear by those Euphonics cabs though, and they're even more. I think that if I had that kinda money to spend on amplification, I'd start by looking at the AI combo. It has gotten a lot of great comments, and as an added bonus, for some reason my wife thinks it would be cool because it's so small & light. Any piece of prospective gear that my wife likes (for whatever reason) tends to get bumped to the top of the list. Funny how that works...

    Alex - if we can manage to hook up when you're here, I'd love to see your cab. Will it be making the trip?
     
  9. AlexFeldman

    AlexFeldman

    Jun 18, 2000
    Chicago, IL
    Definetly - I take it with me wherever my bass goes. My rig plus upright is only 62 pounds total, and I can carry it all myself for about two blocks before I have to stop and catch my breath. ;) Fortunetly we're bringing along some surplus underclassmen to act as roadies during the trip. :D
     
  10. Chris Fitzgerald

    Chris Fitzgerald Student of Life Staff Member Administrator

    Oct 19, 2000
    Louisville, KY
    I've been having a little fun at Don's expense lately because he accidentally did something that cracked me up. Now it would seem that turnabout is fair play. I thought I had a grip on this "ohm" thing after talking to Bob G, but after reading my SWR manual last night, I'm just as confused as ever. May I add that when it comes to anything having to do with ohms and speaker compatibility, I have absolutely no clue what the hell I'm talking about.

    Wow, that's embarrassing!


    My SWR manual says that the Baby Blue delivers 120 watts RMS@8 ohms, and 160 watts RMS@4 ohms. Then I THINK it says that the total impedance of the cabinet is 4 ohms. I've been lurking in the archives a bit, and most of the threads there say that you should not run an amp for any extended period of time at 2 ohms, or you are in danger of frying the power amp. And yet SWR apparently has this combo set at 4 ohms and still has an extension speaker jack on it. In addition, there are no warnings about "ohm overload" when using an extension speaker. It only says, "make sure the impedance of the cabinet you are plugging in is NOT LESS THAN 4 OHMS.

    Reedo says he's never heard of a 2 ohm cabinet, so why would they put that phrase in the manual? Further, if the built in cab is 4 ohms, and the extension speaker is also 4 ohms, that would make the amp run at 2 ohms, right? Which would be bad, right? Maybe I'm just an idiot, but I find the topic extremely confusing...
     
  11. brianrost

    brianrost Gold Supporting Member

    Apr 26, 2000
    Boston, Taxachusetts
    The Baby Blue can drive 2 ohms, at least in theory. I have done this on a few gigs and found the following:

    -- The amp gets VERY warm. It has no fan, just the top vent and if I stood close to the amp it felt like standing next to a radiator!

    -- The power amp clip LED doesn't kick in early enough to warn you. I spoke to SWR about a weird noise (like a "crack") which I would hear when cranked and told them that the amp was not clipping. They told me that the amp probably WAS clipping and that the LED is just not reliably indicating clipping for 2 ohm loads.

    Based on the above, I don't know if I would recommend running at 2 ohms on a regular basis.

    BTW, the power does not increase much if at all at 2 ohms according to SWR's vague specs. One SWR spec sheet I saw claimed 180 watts into 2 ohm loads. That's only a 0.5 dB increase over 160 watts. I have seen the 4 ohm rating listed in various places as 140, 150 and 160 watts. I have two Baby Blue IIs myself, one is marked 150 watts on the front panel, the other is marked 160 :eek:





    [Edited by brianrost on 02-12-2001 at 02:59 PM]
     
  12. Bob Gollihur

    Bob Gollihur GollihurMusic.com

    Mar 22, 2000
    New Joisey Shore
    Big Cheese Emeritus: Gollihur Music
    Sorry, asleep at the switch. Reading SWR's site for discontinued products, they say the Baby Blue combo is 140 Watts RMS @ 4 ohms, 180 Watts RMS @ 2 ohms (with 4 ohm extension cabinet).

    http://www.swreng.com/mainframe.html - right amp?

    You could use an 8 ohm cabinet with it, but depending on efficiency, it might be lower in volume that your SWR.

    You can safely use a 4 ohm cabinet with it, but certainly take Brian's comments into account. You may want to consider...

    - a second amplifier, perhaps one with a single 12" or a pair of tens and serve as an alternative to the SWR; I see from the specs that the SWR has an XLR out so you can chain to the second amp.

    - a 4 ohm cabinet; while the power does not increase much (40w) the extra speaker area will increase coverage. An example I'd recommend would be the Carvin 2x10 (4 ohms) that I owned for a couple years. Inexpensive and a wonderful sounding little cabinet. Light and not too big. The only SWR product I see that might be suitable is their Goliath Junior III, available in 4 ohms, but it's pretty heavy and $$, but a potential match.

    Personally, I'd probably seek another combo entirely or the second one to chain from the SWR. I think having sufficient headroom, as well as simply not coming too close to a rig's capability ceiling is just a good practice to follow.
     
  13. I agree with everything BrianR said. Although possible to run the amp at 2 ohms constantly, I would question its life expectancy.
    But Bob's idea...Hmmm, The Baby blue hooked up to the Contra...Innnteresting..I must go and contemplate this...
    (walks away mumbling...)
     
  14. Chris Fitzgerald

    Chris Fitzgerald Student of Life Staff Member Administrator

    Oct 19, 2000
    Louisville, KY
    Brian - thank you for an extremely informative post. I'm wondering what you meant by "cranked" when you talked about the clipping aspect. The most I ever turn the BBII up is to about halfway on the preamp section and maybe 2/3 on the master. I've never noticed it running hot, but then I'm usually too busy playing (I like to sit about 6 feet away at least) to notice. If I turn it up much past that, the sound gets all "hot" and electric and funky. Would it make a difference in terms of amp life how hard I was pushing it at 2 ohms, or is running the extension cab itself going to heat it up to dangerous levels?

    Bob - as usual, thanks for chiming in. I already own a 2x10 cab that I use for my (thankfully few and far between) BG gigs. It's not great (a Peavy) and it's heavy as hell, but it's alright. I'll check the ohm rating on it. Did I understand you to say that plugging in an 8 ohm extension cab might actually make the amp quieter? Hmmm...I'm not sure what that tiny little cab I tried was rated at, but I think I know what you meant by "coverage". It sounded bigger, a bunch warmer and fatter with the extra cab, kind of like the amp does when it isn't trying so hard, but at a volume more like when it is running out of headroom with only the built in cab. It was a really good sound. BTW, that homemade "Double Bass Max" is really getting the job done, not to mention being a great conversation piece.

    reedo - "walks away mumbling" is about the size of it, especially after Don's AI review. I never liked the GK sound for DB anyway, (I know, cause I have a GK head) but the contra is starting to sound pretty cool. So the idea is (if I'm reading everybody right), if I ran a line out of the baby Blue and into the contra, I could run both really clean and get a huge warm and very "unelectric" sound with great coverage on those annoying loud gigs? Hmmmmm......Peeee-uuuuu!!!!!What's that smell??
     
  15. Bob Gollihur

    Bob Gollihur GollihurMusic.com

    Mar 22, 2000
    New Joisey Shore
    Big Cheese Emeritus: Gollihur Music
    "I understand you to say that plugging in an 8 ohm extension cab might actually make the amp quieter? Hmmm...I'm not sure what that tiny little cab I tried was rated at, but I think I know what you meant by "coverage". It sounded bigger, a bunch warmer and fatter with the extra cab, kind of like the amp does when it isn't trying so hard, but at a volume more like when it is running out of headroom with only the built in cab. It was a really good sound. BTW, that homemade "Double Bass Max" is really getting the job done, not to mention being a great conversation piece."

    What I mean is that the 8 ohm cabinet *may* not be equally loud to the SWR's 4 ohm cabinet, but there are other variables (efficiency) involved. The addition of a larger driver, even 10s, but definitely a 12 or 15 would add some fatness to the tighter-sounding 8's in the SWR.

    Glad the hand-rigged pickup is working; of course, if it's tacky, we can always get you another Bass Max, but I thought it would work and was a way to save a few bucks.
     
  16. Chris Fitzgerald

    Chris Fitzgerald Student of Life Staff Member Administrator

    Oct 19, 2000
    Louisville, KY
    Last night while filling in on a house (jazz) gig in a notoriously loud room, I tried an experiment: I used my old velvet-covered Polytone Minibrute (1x12) as a slave amp to the Baby Blue, taking the XLR line out of the latter into the input of the former. The result was pretty nice, and gave me a lot more coverage than usual before the sound started to get "electric" or "hot". I'm interested in possibly trying this with an AI contra as well if I get the chance. Has anyone tried something similar? There's a possibility that I might be landing a rather loud house (jazz) gig soon (at a place where it is safe to leave some equipment onstage), so I'm trying to find the best option.

    A local music store has a Euphonic Audio VL-110 cab, used, priced at $400. I tried it with a "toy bass" and it sounded great, but haven't heard a DB through it yet. Is this worth looking into as an option for the above situation? Is that a decent price for a used one? Is this an 8 or 4 ohm cabinet? Like an idiot, I forgot to look because there were too many people in the store hanging out and playing both slap licks they know over and over a high volume, which always makes me homicidal if I stick around too long...
     
  17. Bob Gollihur

    Bob Gollihur GollihurMusic.com

    Mar 22, 2000
    New Joisey Shore
    Big Cheese Emeritus: Gollihur Music
    Slaving a second amp is a great solution to more coverage, and often gives you the opportunity of having two different amps for different gigs plus the two for larger engagements.

    The Euphonic Audio VL-110 is an 8 ohm cab.