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BLEW ANOTHER HORN

Discussion in 'Amps and Cabs [BG]' started by pablomigraine, Aug 8, 2005.


  1. pablomigraine

    pablomigraine Supporting Member Commercial User

    Feb 9, 2005
    New York
    VP & Managing Director - Willcox Basses
    I have completely melted yet another comression horn driver in my Basson Cabinet. Now, Basson has been awesome, and has replaced them for free, but I just don't think the tweeter they use in thier cabs is up to par with the speakers. By the time you're throwing enough juice into the cab to get those huge frikken magents pumping, you're already in danger of frying the little horn.....anybody know where I can get really heavey duty horn replacements?
     
  2. BassIan

    BassIan Supporting Member

    Apr 27, 2003
    Cupertino, California
    Can you tell us a bit more? Does that cabinet have any sort of protection circuitry for the horn? If it has a horn level dial on the back, where do you keep that set? What is the brand name of the horn (it should be somewhere stamped on the horn, even part numbers might help), just so we can get an idea what we're working with exactly? Also, it might help us to know what your amplifier settings/bass settings are.

    There are some great replacements out there, but sometimes the problem isn't the tweeter itself.
     
  3. bugbass

    bugbass

    Apr 8, 2004
    Norway
    Usually this happens when the amp go to clip(underpowering), but there can also be something wrong somewhere in your signalchain(amp, crossover etc)
    How many watts does your poweramp give in 4/8 ohm?
     
  4. pablomigraine

    pablomigraine Supporting Member Commercial User

    Feb 9, 2005
    New York
    VP & Managing Director - Willcox Basses
    Okay My signal chain goes just like you see it in my signature, but without the sansamp (sold).

    The Cabinet is a Basson b410b, 8 ohm, no specs available on protection, or crossover point. I'd assume the crossover is at 5khz.

    The cabinet is rated at 1000 watts, I use a Crest LT 1000 which produces a maximum of 1100 watts bridge / mono at 8 ohms. The cabinet has a Horn On / Off switch, no attenuator.

    I bring the input stage of the power amp to just under clip using the preamp Master. I bring the power amp level to exactly 80% or roughly 880 watts.

    Based on the manufacturer settings, my levels above my assumed crossover point of 5khz are as follows: Instrument: flat, Preamp: +3 db at 7khz, and +2 db @10khz (sonic maximizer) These are not agressive treble settings, and are well within the manufacturers specs.

    The factory horn is an aftermarket CTS Peizo tweeter Similar to KSN1188A These are the specs: link

    I literally MELTED the first one, the copper winding was actually melted together and the plasic housing was dripping. There is a circuit board on the inside of the cabinet which reads Dayton Audio ( car audio / audiophile manufacturer) but I cant guess what kind of resistor stage it might have, but I'm thinking it's insufficient. The bottom line is, IMHO, that a 1000 watt rated cabinet needs a sturdier horn than the one it has.

    :bawl:
     
  5. bugbass

    bugbass

    Apr 8, 2004
    Norway
    Maybe you are right about the horn quality.

    But, always turn your poweramp to max output.
    Good quality speakers often requires 1,5-2 times the power rating of the cab.
    So if you put in 880 watts in to your 1000w cab, it may happen that you poweramp runs out of power when you are pushing it
     
  6. bugbass

    bugbass

    Apr 8, 2004
    Norway
    Had a look at the specks of the Crest LT1000 amp, and I dont think it will provide enough power to take your cab to the max level before damage is beeing done
     
  7. CaM90

    CaM90

    Dec 14, 2004
  8. rpatter

    rpatter Supporting Member

    Sep 18, 2004
    Round Rock, TX
    That's not the most robust horn driver. If your horn lens is not destroyed, I recommend trying the Selenium DT150 http://www.partsexpress.com/pe/pshowdetl.cfm?&PartNumber=264-242&DID=7 and replacing the crossover. I'd be more than happy to build a crossover for you. Just PM me.

    Ralf

     
  9. Joe Beets

    Joe Beets Guest

    Nov 21, 2004
    You guys and your wacky tweeters. WAKE UP!! You don't play the piccolo or the violin. You play the bass. Fill up the tweeter hole with automotive body putty, sand it down smooth and forget about it. Your bass will sound better than it ever has before.
     
  10. Eric Moesle

    Eric Moesle Supporting Member

    Sep 21, 2001
    Columbus OH
    Nonsense. Victor Wooten uses cabs with horns, try tapping or slapping without the slight crispness of a horn, and it sounds like you should just be playing root notes for a dirt metal band.

    To each his own. I prefer a tiny bit of horn in my sound. Don't tell me I'm better off otherwise.
     
  11. Thor

    Thor Moderator Staff Member Gold Supporting Member

    Theoretically. a piezo tweeter should not need a crossover
    circuit.

    In practice, you are finding that low frequency energy is
    likely getting in there, and a couple of caps in line to sweep
    out the lows into it may help.

    Peoples theories seem to differ. But I would try the caps first
    before moving on to any other solution. 2 10mf caps from
    Radio Shack in series should be about right.
     
  12. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    The power capacity of that tweeter is about 60 watts. Basson cabs are notoriously inefficient and no single piezo element tweeter is going to have the capacity that you need for the amount of power that the Basson demands.

    Adding caps is a waste of time. Piezo tweeters are not resistive loads and caps will have no effect. Your choices are to either use at least three piezos series wired to provide an adequate voltage rating (and two more horns to mount the others on) or switch to an appropriate dynamic compression driver along with a proper crossover with at least a 3rd order slope.
     
  13. Joe Beets

    Joe Beets Guest

    Nov 21, 2004
    There is no fundamental note or harmonic that can be produced on an electric bass that can come out of a tweeter. Let's do the math. On my bass, low "E" is 40HZ. One octave above is 80HZ. The highest fundamental note I can play, using my top fret on the "G" string is high "E" at 160HZ. Now let's add on the frequencies of the harmonics. Fretting my highest note on the neck, "E", will also produce a harmonic one octave above, at 320HZ. The next harmonic is a fifth above that at 480HZ. Then, up a fourth at 640HZ, up a major third to 800HZ, and then up a minor third to 960HZ. To hear these upper harmonics with your naked ears you must be alone in a sound-proof room. They can be picked up in a recording studio, if the bass is playing alone. But as soon as other instruments are added to the mix they are lost. Maybe it is my classical training, but I like everything coming out of my bass to be actual musical notes. And the highest frequency musical note I can produce is a harmonic at 960HZ. In the real world, my bass doesn't make audible harmonics above 480HZ. So what is that sound that comes out of a tweeter? See for yourself. Play your bass through an adjustable two or three way crossover. Turn off the low frequencies below the crossover point and gradually adjust the high-pass point up the HZ scale. What do you hear at 2500HZ or 5000HZ? This is a sound that you like? If you play the violin you need a tweeter. If you play the bass you don't need no STINKIN' tweeter.
     
  14. pablomigraine

    pablomigraine Supporting Member Commercial User

    Feb 9, 2005
    New York
    VP & Managing Director - Willcox Basses
    BILLFITZMAURICE:
    Inefficient they may be, Dave Boonshoft calls them inefficient, Nick Epifani calls them wonderful, Jorg Schroeder had no opinion. Ineffcient and ungodly heavy I absolutely don't care, they sound wonderful, just wonderful, better than anything I have ever heard with the exception of Schroeders. Now, the first part of your statement, if true would mean that every tweeter in every Basson cab has or will liquifey completely. This is obviously not the case. They cabinet does contain a crossover, assumably as a reliablity measure. So far as I can tell, it's a 24db / octave slope X-over made by Dayton Audio. THis is all a guess on my part based on peeking into the cab with a flashlight and checking out the large Circuit board in back.As far as loads are concerned, caps or otherwise, tweeters are exceptionally high impedance items, but I just don't know how much powers it's getting, and whether that load is within factory specs or not. I can only assume it's not. The problem probably somewhere between the input on the cab and the crossover or resistive stages if any.....either way it's not the best tweeter. Whats the possibility these things are getting fried due to a problem before them in the signal?

    JOEBEETS:
    C'mon man, for alot of guys THUD THUD THUD....BUMP BUMP FUZZZZZZZZ THUD THUD BUMP just isnt exciting....... some even more preposterous and unruly bassists step outside th root occasionally..... :)

    RPATTER: Thank you very much for the reccomendation. I think that unit will do nicely. But what if the problem lies elsewhere??

    CAM90: a little outside of the Price range......and a little silly looking......but they certainly sound sweet dont they....

    BUGBASS:
    exactly. I should not be damaging this cab at those loads. I run a little less than max as that power amp has about .05 db between max and clip / shutdown, so I allow a little room for strong transients. I am looking into a QSC PLX 2402.
    I will be getting a stronger tweeter, but what else could the problem be???????
     

  15. I'm not a big fan of tweeters but there's certainly audible and useable information from a bass guitar above 960Hz. Even your low E produces audible harmonics well up into the kHz. I can certainly hear them in a mix. Do you mean to say that you (we) can't tell the difference in upper harmonic content between, say, McCartney's sound and Entwistle's, even in a mix? How about Geddy's tone, Jaco's? What you're saying here just isn't true.

    That being said, I think that plenty bright tone can be gotten without a tweeter and I also think that compression drivers have no place in bass amps....:D
     
  16. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Sorry Joe, not true. You're entitled to your opinion on the worth of tweeters for bass but your opinion doesn't alter the facts, and the facts are that the harmonics of the electric bass go beyond the range of human hearing. If you choose not to have them in your signal that's all well and good. But please stop telling the rest of us that we're not entitled to hear what we want to from our instruments.

    I hate to seem snippy, but if you're not prepared to take advice why ask the question? You have a tweeter that will take 60 watts. You're using an amp with over ten times that capacity. Do the math.
     
  17. There's several opposing schools of thought floating around this thread, and I shall try not to enter into a debate.

    But a couple of points: First, the statement about the amp only putting out 880 watts. Well, the amp is rated 1100 watts. Turning the volume knob to "8" does NOT limit the amp to 880 watts. All the volume knob does is attenuate the amount of gain the amp produces. The knob setting is almost completely irrelevant.

    Let's put an input signal in and turn the volume knob to 8, measuring the output. For that given voltage level of input signal, the amp may indeed put out only 880 watts. But increase the input signal slightly, and the amp will produce more power. Increase it more and the amp will produce more power, until it clips. W're talking gain here, not a controlled power source, this isn't a voltage or current regulator (until it goes into clipping, at least....)

    Next, 1100 watts (or even 800) is a heckuva lot of power. When a tweeter or horn is only rated 60 watts and the cab has 1100 going into it, even with a crossover, I can see the possibility of the horn going. Isn't there a rule of thumb that says the horn should be at least "x%" (I seem to recall 10%) of the woofer's power rating?

    Also, with this much power, any spike or transient in the signal path will wreak havoc. Turn everything else on, then turn the power amp on last!!! Power off in the opposite sequence--power amp off first, then the rest of the stuff. And don't unplug the bass with the power up!! Those thumps can send unwanted ultrasonics through the system....
     
  18. The crossover basically routes a small fraction of the freq spectrum to the tweeter. And the bass, while having harmonics all the way up, does not have a lot of energy in that freq range in the first place. So depending on the crossover point, how bright you set your EQ, a 60w tweeter could be appropriate for a 1000 watt cab.

    Clipping generates a lot of high order harmonics, increasing the power going to the tweeter. So if I was a guessing man, I'd guess you're either clipping the amp too often, or there's something wrong with the crossover and its feeding excessive energy to the tweeter. Note that clipping your input generates essentially the same harmonics also, (unless its a tube preamp, but you just swap predominantly even order for odd order harmonics) which will be faithfully pumped into the tweeter by the power amp which does not have to be clipping.

    Turning down your power amp input to 80% doesn't limit the amp to putting out 880 watts. If you pluck harder, slap, turn up eq in the preamp, anything that increases the volume, you're right back to full output. The volume control isn't like a light dimmer that controls the power output. It just reduces the gain, requiring a hotter signal to get full output.

    Randy
     
  19. rpatter

    rpatter Supporting Member

    Sep 18, 2004
    Round Rock, TX
    It's all guess work without looking at the cabinet and your rig. I still suspect it's the tweeter. You're using a high power amp along with a preamp notorius for having very hot gain (I know, I have one too). All that going into a piezo tweeter, it's not surprising you are melting them. BTW, I doubt that is a 24db/octave crossover. Dayton doesn't really do any custom crossover design, it's all off the shelf. So what you probably have is a two way 12db/octave crossover. If you want to try the Selenium driver, I can put together a crossover for it. I work with that driver a lot.

    Ralf
     
  20. Funkengrooven

    Funkengrooven Turn it down? You gotta be nuts!!

    Bill I'm gonna disagree with you. I have heard loud and clear the piezo horn tweeters breaking up and crackling when used without caps. It was an obvious noise, I installed caps and the tweets sounded clean. And you are right that piezos are not resistive loads. And the caps certainly don't react like they would when used with a resistive load, but the crackling went away and I didn't destroy any more piezos.
    This is a case of the practical flying in the face of the theoretical which sometimes happens. Try it and see, at worst you will lose an hour of your time and less than $5.00 for the caps if it doesn't work, but if it does......post!!
    P.S. I ALWAYS use caps on my piezos, just as a matter of course, they never crackle and I haven't toasted one in years.
    BTW, SWR uses a cap on the piezo in their Basic Black combo amp.