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Why are some notes so loud?

Discussion in 'Amps and Cabs [BG]' started by scott_barrett, Feb 28, 2005.


  1. Hey all!

    I am using a SVP-Pro preamp that is running to our house PA at church. We are using flown 15's and 2 18" subs. Plenty of power to everything.

    Here's the problem...

    Any G on my bass just explodes! It is so loud they are not playable! The only thing that I could notice is that when I turned down the bass on my preamp, it got a lot better, but now I have lost the bass off of all the other notes. Is this the room? Can this be EQ'd out by the board? I don't have the bass turned up that much, but I like what I'm getting. The other option would be to do it from my bass, which has it's low at 40hz. Would this cause my E's to go crazy?

    Any ideas?

    Scott
     
  2. danomite64

    danomite64

    Nov 16, 2004
    Tampa, Florida
    Heh, I know why. You can't eq it out, and a compressor will only go so far to cure it. Fortunately, it won't hasppen to you next week. Why, you ask? Simple. We live in Florida, and yesterday it was raining all morning, and this always happens to me when it rains, so I'm not surprised it happened to you too. I can't remember, but I think your bass has 2 pickups, Next time, back off the friont one and play over the back one; that is the best you can do with it.
     
  3. Hurley

    Hurley

    Feb 12, 2004
    Cape Cod, MA
    Excuse my ignorance if I'm missing something, but what does rain have to do with anything? :confused:

    Scott, you said it only booms on a certain note? That would seem like the room has something to do with it. I'm sure someone will be able to help.
     
  4. The 0x

    The 0x

    Aug 24, 2003
    Timonium, MD
    Seems like the room's resonant frequency is at G or something. Does everything start vibrating like hell when you hit that note?
     
  5. nastyn8c

    nastyn8c

    Feb 7, 2005
    Tampa, FL
    There are two possibilities that I know of:
    1) It is the room, in which case you can only try moving speakers around or facing them in different directions.
    2) Another mic, most likely a bass drum mic, is picking it up. Everything on the stage has overtones, just the same as your strings or the picture frames that rattle in your room on certain pitches. This is especially likely if the bass drum mic is on a stand on the floor. Bass travels through the floor, up the stand, and into the filaments of the mic. I fixed this problem for myself by taking the mic off the stand and laying it on a pillow in the bass drum.
     
  6. danomite64

    danomite64

    Nov 16, 2004
    Tampa, Florida
    I don't know, but whenever the humidity is real high here, it seems as if nothing cuts through except the low G. And boy does that cut through. It has happened to me on both indoor and outdooor gigs;with different basses and different amps. I'm a Tampa native who has been gigging frequently for over 20 years, and I tell you, it is the rain that causes this.
     
  7. xshawnxearthx

    xshawnxearthx

    Aug 23, 2004
    new jersey
    maybe im buggin, but uh. some notes just have more depth to then.

    like if you hit the D note, on the E string, and then hit the D note on the A string, the D note is louder or more present on the E string.
     
  8. Sundogue

    Sundogue

    Apr 26, 2001
    Wausau, WI
    Humidity will have an affect on how your bass handles certain notes.

    They are made of wood. Especially necks that have no graphite reinforcement. The humidity will cause the wood neck to move and thus cause some notes to be boomy and others to be weak.

    When the humidity lowers it "magically" goes back to sounding fine.

    That is not the case with all basses and ones with graphite reinforced necks should not encounter this problem.

    That doesn't mean thats what is causing the problem scott_barrett initially posted about...but it could be.
     
  9. andruca

    andruca

    Mar 31, 2004
    Madrid (Spain)
    My previous rehearsal room resonated in B. My actual one resonates in D. I think this is more associated with the rooms dimensions and the "effect" can be attenuated repositioning your cabs (try and correct until you get the best results).

    ANDRUCA
     
  10. Nick man

    Nick man

    Apr 7, 2002
    Tampa Bay
    First time I read this I thought "Must be some whacky EQ settings."

    But then it hit me.

    The room's resonant frequencies line up with the note G.

    These guys are probably right.

    Only thing you can do is pick up an EQ and turn down all the frequencies that make the room go nuts.
     
  11. danomite64

    danomite64

    Nov 16, 2004
    Tampa, Florida
    I think Scott uses a Modulus Genesis, so it may not be the humidity thing, unless the humidity actually affects the speaker cones....I really don't know, but the humidity around here is ridiculous at times; even air conditioning takes hours to dry out the air. I am now using a Moses neck because my old oil finish neck would turn to spagetti on outdoor gigs....it was driving me nuts. Anyway, yesterday was one of those days.
     
  12. andruca

    andruca

    Mar 31, 2004
    Madrid (Spain)
    Frankly I don't think it can be the effect of the humidity on the bass itself, 'cause using some squashing compression would solve this and it doesn't (I tried it). What I really don't know is if humidity can affect cabs in any way (I mean, make wood "softer" so that it acts somewhat like a passive radiator -obviously, in a very minimal way, but noticeable- that makes some notes "bigger").

    ANDRUCA
     
  13. andruca

    andruca

    Mar 31, 2004
    Madrid (Spain)
    Or even use 2 or 3 multiband compressors to isolate these G notes (in the different octaves) and limit them (for the whole PA, to avoid this resonance in all instruments).

    ANDRUCA
     
  14. stropsrats

    stropsrats Owner: www.kennedyaudio.com

    Feb 14, 2005
    Valders, Wisconsin
    Scott, I can't say for sure without knowing what power amp your church PA uses, that is a tube powered amp or a transistor type (solid state i.e. FET, MOSFET)
    But I could say for sure if it is tube amp.
    What power amp and how many channels is it, and how
    many speakers per channel?
     
  15. slinkp

    slinkp

    Aug 29, 2003
    brooklyn, NY, USA
    Good suggestions. I've seen both those problems before. Hopefully it's not the room, because there really is nothing you can do to fix that. (If you had really massive amounts of money to throw away, a whole lot of acoustic work might help, but we're talking insane money here.)

    The third possibility is that it's a resonant frequency in the actual PA cabs. A lot of cabs are built for maximum loudness, not fidelity, and many of them have strong resonances.

    Note that I'm no cabinet engineer or acoustics expert, so take the following with a grain of salt.

    A good test would be to turn off ALL mics, find a keyboard with a simple sine wave patch, turn off touch sensitivity, and play single notes up and down the low end of the keyboard, preferably with only one bass bin running. (You can use your bass too but the keyboard test will be more consistent).

    If the G in one or more octaves booms like crazy in this scenario, it's either the bass bin or the room - you've probably ruled out the possibility of a mic problem.

    If the room is really big, i'd tend to guess it's the bass bin. If the room is smallish, it might well be the room. If the problem happens really badly in some spots in the room and less so or not at all in others, that makes me think room problem.

    Hard to say for sure short of trying the bass bin in a more neutral environment such as outdoors. If it booms outdoors you can bet it's the cab and not the room. That might be a worthwhile test, since it sounds like you're going to be playing here every week.

    If it's the bass bin, you're in luck - it CAN be fixed with EQ. Set a parametric EQ to notch out a frequency, set the gain for that band to minimum, and sweep the frequency up and down until you kill the boom on the problem notes. Then gradually bring up the level of that frequency until it sounds as natural as you can manage.

    The EQ *might* sort of help even if it's a room problem - that is, you can make the G less obnoxious by cutting freqs with the EQ, but they could easily end up sounding quiet and murky rather than loud and boomy. Which might be an improvement or not.
     
  16. brianrost

    brianrost Gold Supporting Member

    Apr 26, 2000
    Boston, Taxachusetts
    The sound man should be tweaking the EQ for you. If he can't hear it, he's deaf.
     
  17. Eric Moesle

    Eric Moesle Supporting Member

    Sep 21, 2001
    Columbus OH
    I've rehearsed in rooms over the years that have had big resonant frequency problems, one note would ALWAYS boom in that room. A different room, a different note would always be the problem.

    It might be another mic, but my bet is on room acoustics.
     
  18. amper

    amper

    Dec 4, 2002
    US
    It's your bass.

    I have a similar problem with my '92 Jazz Plus V (and it's not room dependent). The notes on my E string around the seventh fret are quite noticably louder than the rest of the fingerboard--the B will take your head off...compression might help if you've got a multi-band compressor, or maybe a para-EQ might help, too.
     
  19. Hurley

    Hurley

    Feb 12, 2004
    Cape Cod, MA
    That's very strange. I've never experienced that. I'll keep that in mind if I'm ever down there. :p
     
  20. stropsrats

    stropsrats Owner: www.kennedyaudio.com

    Feb 14, 2005
    Valders, Wisconsin
    First the post says 'any G'. Does that mean string or any G anywhere? Then it says E is too loud. So, if we take that literally (no pun intended), it can't be the room size, there are too many notes loud. Secondly the cabinet designs usually won't do that either, both E and G. One thing that would if we are talking strings is the height of an adjustable pickup. Also some bridges and nuts can make a difference I've read. Try a different guitar and eliminate it first. Then if it's a tube eliminate the resonant frequency of the speaker and amp interface by tring a SS amp. (more info about this on my web pages.) Since it's a church I doubt it's the 'room'. But anything's possible, even the pre-amp or sympathetic vibrations from objects in the church like the ceiling plaster or woodwork or another open microphone somewhere else. :spit: