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Newbie Introduction and a question.

Discussion in 'Amps and Cabs [BG]' started by BassIan, Apr 27, 2003.


  1. BassIan

    BassIan Supporting Member

    Apr 27, 2003
    Cupertino, California
    Hey TB'ers. My name is Ian. I'm 18, from Victoria, BC, Canada. I've been an on/off guitar player ever since I could pick one up. Bass has become an obsession to me during the last year. I play in a band, and make it my mission to be more than the guitar follower. I've been browsing here for a few months now, and finally decided to make an account. Unline other industries I've been involved in (Mountain Bikes), you guys really seem to eithier know your stuff or know when to shut up and ask if you don't know.

    Now, on to my question. I recently bought an Ampeg SVT-350 Head (Yes... I know it's solid-state, but right now I'm on a tight budget, and it sounds damn good anyway) and a '98 SWR Goliath Senior cab. The SVT-350 puts out 350 watts into 4 ohms, while the Goliath is rated for 1000 watts, 4 ohms. During my experimentation today, I discovered that as I increased the volume on the head, I got some nasty distortion. With some playing, I discovered that I was clipping the power amp, and turning on the limiter eliminated the nasty distortion. The limiter really squashes the sound though, I find. Should I work on scrounging up the cash for a more powerful head in the future?
     
  2. BassIan

    BassIan Supporting Member

    Apr 27, 2003
    Cupertino, California
    Anyone?
     
  3. BruceWane

    BruceWane

    Oct 31, 2002
    Houston, TX
    If you're not getting the volume you need from 350 watts, then yes, you'll need a more powerful amplifier. Unfortunately, you'll find that increasing your volume becomes more and more difficult due to some well known audio facts.

    Increasing your volume by 3db is generally percieved as a noticeable increase in volume.

    Increasing your volume by 10db is generally percieved as twice as loud.

    You have to double your wattage for every 3db increase in volume....so for example, let's say that you have a 350 watt amplifier, and you are producing 118db.

    To get to 121db, you'll need 700 watts.
    To get to 124db, you'll need 1400 watts.
    To get to 127db, you'll need 2800 watts.
    To get to 130db, you'll need 5600 watts.

    Now, you are probably hitting more than 118db with your current rig - this is purely for illustration..........I am in no way suggesting that you need to hit 130db, or that you need to have 5600 watts................
     
  4. BassIan

    BassIan Supporting Member

    Apr 27, 2003
    Cupertino, California
    Thanks man. I've read that before.

    At least I know I have a cab that'll last me years. If I need more power, a head will do it. I found that by using the graphic EQ and cutting the 40hz a fair bit, I could get significantly more volume before the limiter squashed the sound. Also, for the venues around here, my Bassman 200 was enough, so now I simply have lots of headroom.
     
  5. Hey Basslan, I agree with BruceWane. Another option may be to add another cab. I've been told that it'll push more air and increase your volume - but you'll need to know more about ohms and stuff so you don't blow up your head or cabs.

    BTW, I live in Vancouver. There's a bunch of BC bassists and other Canadian bassists floating around here. Welcome to Talkbass.
     
  6. BruceWane

    BruceWane

    Oct 31, 2002
    Houston, TX
    Yep, that's true, too...........it's called "speaker coupling" and it uses much the same math as the wattage example.

    Take 1 speaker that puts out 94db when driven by 1 watt, measured at 1 meter (the standard procedure for measuring speaker efficiency - db's at 1 watt at 1 meter, AKA 1w@1m).

    This is what happens when you increase the number of speakers, either in one cabinet or in multiple cabinets that are very close to each other............

    1 speaker = 94db, 1w@1m
    2 speakers = 97db, 1w@1m
    4 speakers = 100db, 1w@1m
    8 speakers = 103db, 1w@1m
    16 speakers = 106db, 1w@1m

    The speakers don't have to be identical, but they do need to be pretty close to the same for this to occur. In other words, a 15" speaker cab and a 4x10 don't couple - but two 4x10's do.

    From this, you can see the where the engineers came up with the classic SVT rig, why manufacturers are still sticking to this formula (the 4x10 is the same idea, with an eye towards more portability) and why it is so loud compared to most any other style rig - an 8x10 cabinet is about as far as you can go to exploit the volume boost and still keep it portable.
     
  7. BruceWane

    BruceWane

    Oct 31, 2002
    Houston, TX
    And yeah, you do definitely need to know about ohms and stuff before you go hooking up a bunch of speakers at one time. It's a very easy way to cause your amp to imitate a fog machine.
     
  8. So if I purchased a second 15" cabinet to compliment my 15" combo and positioned it at the opposite end of a stage, I wouldn't get an increase in volume, all things being equal???
     
  9. BruceWane

    BruceWane

    Oct 31, 2002
    Houston, TX
    Nope. You would, however, get better coverage, and that is certainly of benefit if you like to roam the stage a bit. You'd get, say, 118db on this side of the stage and 118db on that side of the stage. Coverage is not a bad thing at all, but if you're trying to increase your volume because you can't hear yourself well even when standing near your rig (or if you just don't like compromising your tone to do so), you'll want to take care of that first.

    Since sound waves generally attenuate ("die off") at, if I recall correctly, about 3db every 10 meters, in many situations you may be better off distributing your cabinets for best coverage. It just depends on the volume you need, at what location, and the distance from the source. One problem with low frequencies coming from two locations, though, is what's called "comb filtering".It's kinda technical, but basically you get "hot" spots and "cold" spots according to where the soundwaves cross from the two sources, and this varies according to frequency. At some points, the waves are out of phase and cancel each other out.......usually, in the smaller venues (aka "dive bars") that we mere mortals usually play in, the sound is actually better if you put all of the PA on one side of the stage due to this effect. However, if you try to explain this to your band mates, or to many less informed sound men, they will indeed think you are insane, and besides, it does look a little funny to have all the PA on one side, so I wouldn't push the point too much.
     
  10. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    Who told you that?
     
  11. BassIan

    BassIan Supporting Member

    Apr 27, 2003
    Cupertino, California
    Something I've noticed. I'm coming from a rather deep involvement in the bicycle industry which is full of people who are what we called "armchair engineers" when they are on the mountain bike message boards. They really have no clue of what they're talking about, but natter on regardless. I don't see that here.

    As far as adding extra cabs, I'm not willing to do that right now. If I'm gonna spend money it'll be for a more powerful head to power my monster 1000W cab. I know it can go a lot louder. Until then I'm using the limiter all the time and not cranking the head too much. My rig also includes a Fender Bassman 200 as my "powered sub", so to speak. It picks up some of the rumbly bottom end.

    Thanks for the interesting information on doubling up speakers and the sound level increases.
     
  12. Before you dump a bunch of money into a bigger head it would be a good idea to take the whole thing into a music shop and try both heads. The difference in volume betwee 350 and 1000 watts is only about 4db or so. Have you played actual jobs with the rig as it is? I have a friend with that same cab that used a SWR 350 watt head with it and thought he just couldn't live with out the 750 SWR model. Well he got it and guess what? He doesn't play any louder than he did with the 350. Big waste of money, but, he's now over his GAS now.
     
  13. BassIan

    BassIan Supporting Member

    Apr 27, 2003
    Cupertino, California
    I'll definitely try anything I'm considering dumping cash on extensively. I'd just feel happier not having the limit light coming on so often. I'll consider your comments though, and for around here this setup is more than enough for what I'll be playing at. Heck, my Bassman 200 alone was good enough for one show we played.

    The head is down on the list, well below getting a nice bass.
     
  14. Tsal

    Tsal

    Jan 28, 2000
    Finland, EU
    I think you should be pretty well off with the 350w head, atleast you should be able to hear yourself without the amp clipping like mad. I know I can with my 350/4x10-setup.

    I see three possible reasons: either you have too much gain on which leads to distortion, or you have the EQ up at full tilt on some bands which might lead the same result. Or, your tone is drowned by guitarists and their 7-string guitars and downtuned strings and their 350w Marshall "numetalamps", and you have to turn the head all the way up where it distorts.

    Seems to me you already found out that cutting the worst lows a bit helps, eh? If you are tailoring with the EQ, it would be better to cut others a bit than boost one to max, and since low frequencies demand alot of power it distorts more easily there.

    The next step would be to fiddle with your and your guitarists' EQs to make yourself audible, so that you could be heard from between other instruments without overdriving your amp.

    Oh, and don't you worry about that tube amp thing. You don't really want to lug around some 250lbs 400w tube amp, so here in bass world we have left such matters aside and use primarily solid state power sections, usually with preamp that has blendable SS and tube sections.

    Welcome aboard mate, and good luck.
     
  15. BassIan

    BassIan Supporting Member

    Apr 27, 2003
    Cupertino, California
    Haha, we're all a little beyond the nu-metal and trendy punk/pop stuff. No downtuned 7-stringers here! I run my gain at half, so the preamp clips only during aggressive slap sections, and the preamp EQ knobs are pretty much flat with a little boost in mid and treble. I run the graphic EQ with no boost at 40hz (that really causes clipping), about 4-6db boost at 80hz (still picks up lots of good bass, less clipping), and some boost in the mid/treble section. I'm not cranking everything way up, I know that's not smart. I'm very sure my rig will be more than enough for any shows around here.

    I will definitely try working with the guitarist on his EQ, as he does run a rather bassy setting through his rig right now.

    Thanks everybody for the warm welcome.
     
  16. BruceWane

    BruceWane

    Oct 31, 2002
    Houston, TX
    Yes, do this. We probably all have the habit of getting a wonderful, full range tone while practicing at home, but then the band gets together and nobody can hear themselves, people start turning up the volume, and you end up with a mess.

    I think the single most damaging thing to happen to bass players in the past 25 years was Eddie Van Halen. He cranked up the bass on his guitar and gave birth to the dreaded "brown sound", and suddenly there was no audio space left for the bass to occupy. Seriously, you listen to most Van Halen tunes, and it seems that Michael Anthony was given a job only because it was unthinkable at that time to have a rock band without a bass player, not out of sonic or musical neccessity. No slam on M. Anthony, or Eddie for that matter, talented folks, sure, but Eddie's huge influence did make living with guitarists a lot harder.

    Anyway, what I wanted to say, was that a common trick of sound engineers is to "notch" the individual instruments to give them definition in the mix - i.e., guitar 1 gets an eq hump at 1.5Khz, guitar 2 gets an eq hump at 1.9Khz. Give each instrument a bit of it's own sonic space to dominate. The individual instruments will NOT sound perfect when listened to alone, but they'll be much more distinct in the sound of the band as a whole.

    So you guys cooperate, ask the guitarist(s) to kindly let you handle the lows, and everybody will be much happier.
     
  17. MauriLii

    MauriLii

    Jan 19, 2003
    Kent, England
    Cool!! Would that mean that my band doesn't need to rent one at Halloween anymore?:D

    So in a nutshell....

    -more speakers
    -more efficient speakers
    -more power

    Oh yeah, and trying to get guitar players to change their tone is like... Well, I can't say what it's like 'cause I've never been able to do it. Maybe I should reverse the bass and treble pots on their amps. Hmmm....

    Good luck on that one anyway.

    P.S. Welcome to TB. It's a pretty neat group of people here.