Two 4 or Two 8 Ohm Goliath Jr. speakers?

Discussion in 'Amps and Cabs [BG]' started by Music Attorney, Apr 2, 2004.

  1. Music Attorney

    Music Attorney

    Feb 22, 2004
    I want to buy SWR Goliath Jr. III cabs. My question is do I get two 4 ohm or two 8 ohm cabinets?

    I swear to you I have searched and read in the TB forums. I have done the same thing on the Internet (e.g., Harmony-Central, etc.). I can normally get my head around most concepts/ideas. BUT I still am not clear on this whole headroom/efficiency/ohm thingy.

    My situation is this: (i) I will be using an SWR SM-500 and the SWR Mini Mo; (ii) I have this notion that I want to run 2 cabinets in stereo; (iii) I definitely want a 2x10 configuration; (iv) I will be using my set up in non-professional settings (note – there may be very good players present, but not playing for money); (v) I don’t care about resale value; and (vi) it’s unlikely I will be playing anywhere or with anyone that would require anything more than moderate volume (i.e., small rehearsal rooms; coffee houses; small-mid size clubs, etc.).

    You would think it would be enough for me that the SM-500 manual says: “When used in Stereo mode, the internal power amplifiers of the SM-500 will deliver 300 watts @ 2 ohms, 250 watts @ 4 ohms and 150 watts into 8 ohms. Optimum performance will be achieved by using a total of 4 ohms per channel.” However, the lawyer side of me asks what SWR means by “optimum performance.” Does that mean the amp’s power, headroom, sound, and whatever else are all optimized by two 4 ohm cabs? If so, ‘nuff said. But I don’t see that definition anywhere and my reading finds players suggesting different approaches (i.e., 4 and 8). Hopefully, I’ve given you enough to suggest what’s best for my needs. Thanks.
  2. Here's a really simple explanation:

    The lower the impedence value of the speaker load (2, 4, 8 ohms) the more power will be produced by the amplifier. A higher impedence value will equal less power from the amplifier.

    Does that help?

    Basically, your SM 500 is capable of driving two 4 ohm cabinets in stereo mode. The wattage will be split evenly between the two cabinets; 250 watts per cab. With that 250 watts into your chosen cabs you'll be able to acheive a max SPL of 128db according to the specifications of the Goliath Jr. III. You'll gain another 3db by using two cabinets, bringing the total SPL to 131db at full power. That's going to be pretty freaking loud. Keep in mind that these cabinets will produce little under 45-50hz. They will not "speak" with authority on a low B string (31hz) and might even "fart" on some of your lower notes like E which is 41hz. These things will tend to get more noticeable the louder you play. That's where headroom starts to come in but that's another story...
  3. seanm

    seanm I'd kill for a Nobel Peace Prize! Supporting Member

    Feb 19, 2004
    Ottawa, Canada
    The mini mo' is a preamp and the SM500 is a head, you don't really need both. A head is a preamp and power amp combined. I would drop the mini mo' or drop the SM500 and get a power amp such as the 750.

    guyplaysbass has it right, so I will not repeat what he said. Just a note that the SM500 can be run bridged.

    As an aside, why choose the two 2x10? As guyplaysbass said, you will not get great lows. A 2x10 and a 1x15 would give a better range. And 2 1x12s will give you a small rig for coffee houses and small gigs and both for medium sized gigs. Two efficient 1x12 will be louder than the 2 2x10s.
  4. mike mcd

    mike mcd

    Dec 11, 2002
    I have two 8 ohm Goliath Jr. III's being powered by a Bass 350. For the playing situations you described, you would be getting PLENTY of low end from these cabinets. They will also do an outstanding job producing a low B or anything above. Having 2 2x10 cabinets is a great way to go in my opinion. It has worked great for me.
  5. cb56


    Jul 2, 2000
    Central Illinois
    I agree with mike mcd. The Goliath Jr's have great low end for a 210 cab. But I would suggest running two 4 ohm cabs. I have two Goliath II Jr's that are 4 ohm cab's and have run them the way your SWR500 manual suggests.(one each side at 4 ohms. The difference being I used my Ampeg B4r for the amp. I also stacked the cabs on top of each other so it looked like I was using a 410. What I can tell you is this set up will cut through a pretty loud band without PA support in a medium sized room. (typical sized bar or banquet roomfor example) The low end will be good. I play a 5 string and am perfectly happy with the low B from those cabs. Also the cabs are very light and easy to transport. The only drawback is , the cabs are not very tall so even with stacking them on top of each other I had trouble hearing myself on stage even though the cabs sounded great out front. Keep in mind I was in a very loud band situation. I think putting the cabs up on a case or something to get them up higher would help. I've been considering selling mine. $600 for the pair PM me if you're interested. Don't really care if I sell them or not. I have enough speaker cabs for 3 1/2 rigs and don't really need all of them.
  6. Music Attorney

    Music Attorney

    Feb 22, 2004
    guyplaysbass, seanm, mike mcd, and cb56 thank you so much for your responses.

    guyplaysbass: I definitely understand lower impedance = more power. Unfortunately, you stopped at the headroom part. I’m unlikely to ever need “pretty freaking loud.” Therefore, even though the 8 ohm cabs will give me less power (but still probably enough for my purposes), will they give me more headroom and thus help the cabs speak with “authority” on the low B? Or will more headroom come with the 4 ohm cabs?

    Seanm: I discussed why I’m getting the 500 AND the Mo here:
    And I discussed why I want the 2x10 configuration here:

    mike mcd: That’s great to hear! It’s like doing legal research and finding a case that’s exactly on point and says your client is going to win big ;-) Notwithstanding your satisfaction with the 8 ohm cabs, any thoughts on whether there is even some additional benefit of going with the 4 ohm versions other than more power?

    cb56: Glad to hear you agree with mike. The low B comment is great news. Also, portability was my next priority after sound. Although it’s unlikely to happen very often, I appreciate the tip on getting the cabs up off the floor if necessary. Finally, I’ve read some back on forth the II’s versus the III’s and I’m going with the III’s, but I sure appreciate your kind offer.

    Again, thank you all!
  7. The 4 ohm cabs will get you the most power, in effect providing you with the most headroom from that particular amplifier. What a lot of guys choose to do (myself included) is run an amplifier with twice the rated power of the cabinets. This will give you enough power to handle any transient spike in your signal and not take away from the amount of power needed to still accurately produce your lower notes.

    It's the low frequencies that require large amounts of power. As soon as you start pushing the volume your power reserves (ie; headroom) are depleted rather quickly as the amplifier trys to keep those low frequencies as loud as possible. This is when "clipping" often starts to occur. By having additional power in reserve you won't run into this situation as quickly, giving you more volume of all frequencies before clipping.

    About your B string: The Goliath Jr III will not effectively produce frequencies under 45hz. The reason people "think" it handles the low B is that the harmonics of the fundamental frequency (31hz) are very strong with this particular cab design, in the 60-80hz range. This design was made popular by David Nordschow first in the SWR cabs and later in the Eden "David" line. Many people have come to accept this as "bass" but in reality it is not. If you've never heard 31hz at a considerable volume then you're really missing out.

    That's why I use an Acme Low B-4
  8. seanm

    seanm I'd kill for a Nobel Peace Prize! Supporting Member

    Feb 19, 2004
    Ottawa, Canada
    Great. I am all for flexibility. I was worried you thought you *needed* a preamp with the SM500 (I didn't realize you already had one). Just trying to save you some $$$$

    I would still put a 12" or a 15" with the 2x10", but that's just me. You have my permission to buy the two Goliaths :p
  9. monkfill


    Jan 1, 2003
    Kansas City

    I think you need to be careful with statements like this . . .

    First of all, an Ampeg SVT/810 rig hits -3dB at 58 Hz, and plenty of people accept it as "bass." You can't just rely on a spec sheet to tell you what something will sound like.

    I've also heard of plenty of situations where the soundman will roll off frequencies below 50 Hz or so because they gett too muddy or boomy for the room. There are more factors to consider than whether your cabinet will hit the magic number of 31 Hz . . .
  10. I think you will get your best possible sound with the setup you are using by going with 2x4ohm cabs. This is going to give you another 2 to 3 db of headroom. The fact that the amp is rated at 2 ohms per side tells me that it should have no problem with a 4 ohm load.
  11. cb56


    Jul 2, 2000
    Central Illinois
    Excellent post. Use your ears not your eyes when trying out a cab :bassist:
  12. I have not given any un-true information. I was merely stating as to why people think an enclosure that is only capable of 45hz can reproduce the low B string "with authority". In reallity it can reproduce the harmonic content of that frequency (61.74hz) at a pretty high db, but not the frequency its self. Your reference to the classic Ampeg enclosure is further proof of this time-tested and accepted "norm" in the bass enclosure industry. Modern technology allows for so much more these days. I added my opinion as to him "missing out" if he'd never really heard his low B string in all its glory.
  13. Music Attorney

    Music Attorney

    Feb 22, 2004
    guyplaysbass: Your explanation on headroom and low B matters was most helpful. Thanks. By the way, an Acme Low B-2 Series II is on my short list of options if the SWR’s don’t deliver.

    seanm: greatly appreciate you looking out for my “back end” (i.e., my wallet) ;-) When I read you granted me permission to buy the cabs…………well………….. I got a little misty. Thank you, thank you, thank you. I won’t let you down.

    monkfill/GreyBeard: gentlemen, your input/opinions are certainly appreciated.
  14. It's all good! Let us know how things come along. I'm interested in hearing about how you like the Mini 'Mo. Keep us up to date!

  15. monkfill


    Jan 1, 2003
    Kansas City
    Well, I guess I was rubbed the wrong way when you said "Many people have come to accept this as "bass" but in reality it is not."

    Yes, there is certainly merit to hearing the true fundamental of the low B, and while you are giving "true information" about specs and frequencies, your statements about "true bass" and "authority" are subjective and might lead someone that is uninformed to pass over some pretty impressive gear simply because of what the spec sheet says.

    I don't know, I think its easy for a lot of us (myself included) in our discussions to become too fascinated and obsessed with descriptions and specifications and we forget about actually playing. . . but I digress.

    Again citing the SVT/810, that rig doesn't do anything without "authority."
  16. chadds


    Mar 18, 2000
    I used this combination for ten years with two pairs of Jrs. and two sm400s. I did it for portability. Stacking two vertically became the position of choice as it projects better, See ancient article from Turner about the Deads stacks and how bass projects. This is a healthy ohmage for the head as well. I often used one for those coffee house gigs. Good luck. P.S. If you have need for 2 2x10s though, 1 8 ohm 4x10 goliath III is much much more than two 2x10s because of cabinet internal volume.
  17. I'll give you that!!!
  18. chadds


    Mar 18, 2000
    Yeah, let's keep this in the realm of useable. The wavelength of the low notes we produce is so long that it's out of the building of a large club so we do have to hear the higher level harmonics to play and enjoy this instrument and music that contains these frequencies. Those Goliath Jr. IIIs will not be farting unless you overdrive the preamp or play ridiculously loud and you stated that wasn't your intention. I'm a fan of them as they are very quick and clear.
  19. malthumb


    Mar 25, 2001
    The Motor City

    It appears you already have the answer to your 4 v 8 ohm question, but if it helps confirm things for you, I played an SM500 through two 4 ohm SWR Triads for years. The Triads are a 15 and a 10 with a horn. Worked fine for me. This configuration seemed to pick up the B just fine. Apparently the 15s helped in that regard.


  20. If your question was about the impedance dipping to 2 ohms, the key phrase is "PER SIDE." In other words running 2x 4 ohm cabinets in stereo is effectively running 4 ohms, not 2 because each channel of the stereo is independent.

    HOWEVER bridging the 2x 4ohm cabs would be a bad idea.

    Running both cabs in one channel of the stereo is pushing the amp to it's limits, not the best idea long term.