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something that confuses me about big amps

Discussion in 'Amps and Cabs [BG]' started by Corwin81, Apr 13, 2003.


  1. Corwin81

    Corwin81

    Mar 18, 2003
    Ames, IA
    I currently run a 220W solid state head(Crate BXH220) into a Crate BX810e cab. Even when using just stage volume, I never have the volume above half crank and I've always gotten complaints that I'm too loud in the mix(average of 120 people crowds). I mainly go through the PA. I've seen people using Yamaha CP2000 or QSC RMX1450 amps for medium gigs. Is it just the headroom? Or do you actually use that much power? It's almost confusing me of what to get for a power amp for my next rig(pair of Avatar B112s once the front port ones are available). I know I'll be using the Crate for a while though.

    Just a thought. and something I've been curious about for a while.
     
  2. jondog

    jondog

    Mar 14, 2002
    NYC metro area
    Yes to headroom. I frequently run only one side of my power amp. Also, if you have an 8 ohm load many power amps aren't as crazy loud as the 4 or 2 ohm specs that people brag about. You're also running 8 10"s which is a lot of speaker area. Some people are running smaller and often very inefficient cabs that eat a lot of power for the same SPL as you have.
     
  3. ESP-LTD

    ESP-LTD

    Sep 9, 2001
    Idaho
    Some of it's headroom but most of it is speaker efficiency and cabinet design.

    I don't know much about the Crate BX180, but I'll make a few assumptions. It's probably a very sensitive cab (lots of volume per watt) at the expense of lows (probably 6db down at 50hz, 12db down at 40hz and 20db down at 30hz).

    My 3x12 system can probably only get 1/4 as loud as yours (maybe less) and that's with 1,000 watts or so pushing it, but it's flat down to 30hz, so my lowest note is as loud as my highest note, and I can probably produce more absolute volume at 30hz than you can.

    Get all the power you can; you don't have to use it all (headroom) but it gives you more choices for speaker cabinets down the road. Speakers that go low, do not go loud without a lot of power.
     
  4. Corwin81

    Corwin81

    Mar 18, 2003
    Ames, IA
    so if cabs that don't go low are louder, that means Avatar cabs are pretty loud? I just use a 4 string and go for more of the mid punch than the low boom. my EQ is more of a frown than smiley face.
    I never thought the 8X10 from Crate would be much. I think they discontinued it after a year because of the size and people probably just went with the Ampeg 8X10, but I've also heard that Crate's BXH-220 and the cabs they were offered with were the "high end" Crates with similar quality to SWR, but shunned because of commiting a Crate crime.

    but back to the main point. I've also used a 50W blackface Fender Bassman in the 8X10 and it was loud enough, but I guess I'll end up going with a Yamaha CP2000 even though Fender Bassman 100 or 135 is something I'd also consider, but not sure if 100W is enough for a pair of Avatar 1X12s.
     
  5. jondog

    jondog

    Mar 14, 2002
    NYC metro area
    Yes, the Avatars are supposed to be loud but not low. Even so, 100W is probably not enough for them. Why are you changing rigs? What are you looking for that the Crate doesn't give you? Portability and name recognition seem to be working against your rig, but don't let those stop you if you like your tone.
     
  6. ESP-LTD

    ESP-LTD

    Sep 9, 2001
    Idaho
    Yes, I'd say Avatar leans more towards loud than low.

    If you're pushing lots of mids I'd consider starting with an 8 ohm 4x10 of some kind; they have all kinds of mids. If it needs more lows, then you could add an 8 ohm 1x15 or 2x12 under it, and still push the pair with most "4 0hm" heads.

    For a performance rig, I don't think I'd buy less than 350w or so. There are so many good choices for decent prices.
     
  7. Mike Money

    Mike Money Banned

    Mar 18, 2003
    Bakersfield California
    Avatar Speakers Endorsing Hooligan
    Let me get this straight you are using a 220w solid state crate head and a Crate 8x10 cab?

    And you are getting complaints that you are too loud?

    Maybe is it just me, but I wouldn't think 220w would properly drive an 8x10... but that is just me...
     
  8. Bonafide

    Bonafide

    Oct 15, 2002
    Hey ESP,
    what 3-12 cab do you have? Or is that 3 seperate 12's and if so which brand / model?
    The higher end cabs I have owned/tried, Epifani, Euphonic, SWR, Ampeg, and Aguilar don't have those kinds of specs. I'm intrigued.

    Thanks.
     
  9. I used to think so, until I talked to a guy and he used a 100W head to drive a 4x10 and 1x18 stack, and kept up with a raging Marshall full stack....I still don't know how...But I believed him...And as long as he's not clipping his amp, I'd consider it properly driven...Not pushing the 8x10 hard...but driving it, somewhat
     
  10. Corwin81

    Corwin81

    Mar 18, 2003
    Ames, IA
    It's not the name recognition. It's the portability. I'd still use the Crate for local shows, but for out of town shows, I'd rather use a smaller rig(especially the next one where there's 2 flights of stairs to lug the cab through to get to the stage). It saves on gas and the amount of cars we have to take to get the stuff to the venue. The Crate stack sounds really good and gets the tone I want, but at the expense of size and a dolly that has a half broken wheel. I'm guessing the 8X10 is a loud, but not low cab since a bassist that plays a 5 string had the bass EQ cranked and highs taken off and the amp was almost dimed(limiter was active a lot) and I could barely hear him(metal band), but I can get by with half the volume with the mids cranked and the lows rolled off(that's what the 15s or 18s in the PA is for, I like my mid punch).
     
  11. Corwin81

    Corwin81

    Mar 18, 2003
    Ames, IA
    I'm going with the 1X12s or 2X10s for the portability sake.
    Haven't used 15s, but from the tones that I like and people that have that tone, I don't think I'd like 15s. 12s at the most. I like having punchy tone as opposed to the boomy tone.
     
  12. cjgallen

    cjgallen

    Oct 19, 2001
    I'm pushing an Avatar 2x10 and 1x15 with 1500watts and I'm still not loud enough :bawl:

    Do I just need more speakers?
     
  13. ESP-LTD

    ESP-LTD

    Sep 9, 2001
    Idaho

    From 150hz and up I'm using an Avatar B112 with an Eminence Kappa 12.
    Total investment: $180

    From 150hz down I'm using a pair of 4 ohm 1x12 cabs I built using JBL GT-120's in a 2.4' box tuned to 28hz. These are car audio subwoofers (80 oz magnet, poly cone, rubber surround).
    Total investment: $300.

    I biamp with an old Yamaha preamp and a QSC-RMX 1450 to push the B112 on one side up to about 275w and up to about 700w into the 2 ohm load of JBL's on the other. They are a "close" match in sensitivity with the Avatar being 2-4db more sensitive.

    I played a bolt-on 4 string for many years, and then played a neck-thru and discovered there was a LOT of low frequency stuff that my amp couldn't handle anymore once I gave it a signal with high fundamental content. When I moved to a 5 string neck-thru the problem was even worse, and so I began looking for a rig that was dead flat down to my lowest note.

    It grows on you, but it sucks power.
     
  14. BassWizard55

    BassWizard55 Guest

    Dec 21, 2002
    Rome, Ga


    The Yamaha preamp has cross-over control?
    Also, Bonafide might have asked this but what are the brands of the boxes that are tuned to 28hz. And why did you choose JBL over all the other subs and eminence?
     
  15. ESP-LTD

    ESP-LTD

    Sep 9, 2001
    Idaho

    The specs are at: http://manuals.harman.com/JBL/CAR/Boxes and Parameters/GT120_f.pdf

    I selected this speaker because the JBL name gave me some level of confidence, Fs was below 30hz, and I could buy them for $55 each. If you want to spend some real money they make some amazing car audio subs.


    The issue is the definition of "handle". The problem I faced was that I could tell a difference in tone between the low notes and others; in fact I have played lots of cabs that I though were marginal on lower notes on "E". To me "handle" means it can reproduce that note as well as any other. That means flat to my lowest note. When I buy stereo gear, I want it to be flat to the lowest note my source contains and I can hear, why is that unreasonable in bass gear?


    I disagree. It may well be that the keep things clean for PA support, that bass onstage is reduced, but IMHO that is normally done as a result of reducing overall volume onstage.



    I believe that reason is cost. I'm sure there are other opinions.


    I leave my EQ essentially flat on the bass and the preamp and use standard tuning. My Yamaha PB1 is an old solid-state rig from the 80's. It has internal high-pass and low-pass filters instead of a single crossover, but I normally set them both at about 150hz so it works out the same. The subs start to rolloff at about 200hz by themselves.



    I hear things like "never had trouble with" and "handles" a low B. An AM radio in a car "handles" low B all the time. I wanted the same performance from those notes as from the rest, and in this case I was willing to pay for it (in reduced volume).

    I suspect a 150w Peavey combo gets louder than my rig and I don't recommend it for everyone or every situation.
     
  16. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    8x10's is a lot of speakers. Look at it mathematically.

    To get a 3dB increase in volume, you need to double your wattage. The other way to get a 3dB increase is to add an extra speaker (forget about impedance issues for now). Your 8*10 has lots of extra speakers and therefore lots of extra dB.

    To get the same volume out of a 4x10 with the same speakers, you would need a lot more watts. Chances are a 4x10 with the same speakers won't go low enough, so they would probably make it with speakers that go lower. The sacrifice for low frequency response is lower sensitivity. So to get the same dB, you need more watts again.

    I've found 400w is enough to overpower a drum kit if you use enough speakers. But portability is a big part of speaker selection. If it wasn't, bass cabs would be made of concrete. Not everyone is prepared to haul around a fridge.
     
  17. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    Not really. Most Hi-Fi speakers incorporate a passive sub-sonic filter to chop off anything below a cratain frequency. Why? Have a look at any cone excursion graph for any speaker cab and pay attention to what happens below the cabs tuned frequency. Cone movement increases dramatically if a speaker is subject to program material that contains frequencies below Fb, reaching Xmax all too easily and Xmech without too much extra effort. Obviously the louder you play, the worse it is, but pushing 31.5 hz into a cab tuned to 50hz is a great way to blow a speaker.
     
  18. Bonafide

    Bonafide

    Oct 15, 2002
    It wasn't intended as an argument but I was sincerely looking for a logical answer.
     
  19. Captain Awesome

    Captain Awesome

    Apr 2, 2001
    PDX
    Yes.
     
  20. ESP-LTD

    ESP-LTD

    Sep 9, 2001
    Idaho

    Interesting I didn't know they used any filtering on cheap radios. I'd always assumed they just let nature take it's course and figured the distortion would be enough to convince folks to turn it down.
    I agree with you completely. The thrust of my argument is that folks have some tolerant definitions of "handling". I wouldn't buy a stereo that was 3db down at 120hz, and I won't buy bass cabs that are 3db down at 60hz.