Power amp loudness?

Discussion in 'Amps and Cabs [BG]' started by Naggon, May 29, 2007.

  1. KPJ

    KPJ

    Oct 2, 2001
    Methuen, MA USA
    How many years experience of acoustical and electrical engineering do you have? Could you please coherently, and with great depth, elaborate on your theories of efficient loudspeaker design?
     
  2. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Since most speakers in bass guitar cabs run out of excursion well before 1/2 of their RMS/thermal rating, there's usually little point in having an amp/head with any larger of an RMS rating than the summed speaker RMS/thermal rating. That still usually gives a minimum of 3 dB of headroom.

    Of course one can often find bass rigs where the full power the amp can make is seldom ever called upon, because it would just fart the speaker out anyway. A fair number of players who have real powerful amps run the amps under their duty cyle (some without even realizing it) unless more cabs are hooked up for larger gigs. Even then...

    With PA it's a whole different game - then it makes sense to have amplifiers with MORE RMS (1.5 to 2 times as much) on tap than the speakers are rated for, because crossovers are used which limit the bandwidth going into mains and subs, and the xlim and/or xmax of subwoofers is usually up to handling more than full RMS.

    * * *

    I too would like to hear a detailed answer why the Bill Fitzmaurice cabs are flawed in design.
     

  3. how many years that i have of acoustical and electrical engineering is irrelevant because speaker builders and designers like myself know that in a horn loaded system any thing above about 500 hertz and this is being quite light needs to be as straight as possible i.e. no curves or bends or folds due to the cancellations that occur and just because I'm 16 and still in high school does not mean i do not know any thing about acoustics or electrical engineering. and as far theories i don't need them because if i can not prove them i see no point in waisting my time with them any thing else? now as i said before sorry if i offended any one
     
  4. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    You are wrong. Look at a wide variety of waveguides, stepped horns, constant directivity flares, etc. A majority of midrange and treble horns do NOT have concentric slab sides. Take a look at what is all around you.
     
  5. did you not just read what i wrote MIDRANGE and folded horns do not mix well they are like oil and water you'd think i would know after being p.o. about how horrible those dr300's sounded
     
  6. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Sorry - you are confused about his designs and what's doing what, and you have me confused for someone else as well, I think. DR300?
     
  7. bassbrock

    bassbrock

    Feb 20, 2007
    Callahan, FL
    So, uh, back on topic --- hint ---

    To the original poster - maybe I missed it, but are you using a preamp, or are you hooking up your bass directly into the quarter jack input of one side of the amp?
     
  8. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Nothing wrong with that two-way multi-horn design, different horns handling different frequency bands, I would guess that probably 500 Hz and up is handled by the flares in the center. Looks like a good plot too, and I'd assume it gets even better as a vertical array is built up.

    Here's a good whitepaper that covers a lot of horn design advancements right up to Peavey's Quadratic-Throat Waveguide:

    http://aa.peavey.com/downloads/pdf/qwp1.pdf
     
  9. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    In the very first post OP says:

     
  10. 1st thanx for the info on his pre
    2 its not a multi horn its only 1 horn with a split mouth
    3 just because something looks good that doesnt mean it sounds or performs good
     
  11. Jeralya

    Jeralya

    Sep 7, 2006
    Chicago, IL
    unclejam, something you should learn fast in life is that no matter how 'awesome' your ideas are, if it physically impossible to understand a word coming out of your mouth, then it all means nothing.

    Yikes.
     
  12. well i dont know about physically but mentally you should be able to grasp what i am trying to say
     
  13. afroman

    afroman

    Aug 31, 2000
    Austin, TX
    Something is probably wrong. The DCM1500 I used to have, was loud as heck. I actually blew 2 speakers from my old Aguilar GS410. It did sound great and I could just feel the headroom of the poweramp. No straining and just clean gobs of power. I used mine with BBE Bmax and Bmax-T and the Fender TBP-1. Is was great with all of them.

    I hope everything turns out ok and go enjoy that DCM.
     
  14. Rick James

    Rick James Inactive

    Feb 24, 2007
    New Jersey
    You're kidding, right? I've got strings that are older than you are. The BF cabs I built are the best I've ever used, or heard. You may know something about acoustics and EE, but the last time I checked high schools weren't giving out Masters degrees to sophomores.:rolleyes:
     
  15. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Read the description. It uses two PSD2005 - see them in between there? For the bandwidth BELOW THAT it uses the larger horn assemblies.

    Just because it looks good doesn't mean it is crap either. You really need to edumacate before dissing anything you don't understand. Start by reading the description.
     
  16. to Rick James they are the best that YOU HAVE HEARD
    and i did not say that i have master degrees in those fields
    to green boy

    read what i TYPE MIDRANGE NOT TWEETERS if you want to argue about this i really dont care i have plenty of time to do so i am not yelling @ you it just emphasis now let me educate you when talking about horn loaded cabs when discussing the mouth of the horn tweeters are not included
     
  17. Warr Tapper

    Warr Tapper Inactive

    Sep 17, 2006
    Work
    Just look at UncleJam's signature. Behringer Rulez? That should tell you everything right there.
     
  18. yeah its different then all the ampegs and mark basses and epi's and what not do you realize how much money i would haveif someone gave me a penny for every peice of ampeg gear i saw that was not at a music store id be filthy stinkin rich?
     
  19. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Those smaller horns in between carry midrange AND treble. Clue up, please.