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Adding a tweeter...

Discussion in 'Amps and Cabs [BG]' started by jock, Feb 1, 2004.


  1. jock

    jock

    Jun 7, 2000
    Stockholm, Sweden
    Id like to know the theory about how to add a tweeter to a cab. Does it change the impedance? Do I need a crossover?
    The cab has a 8 ohm 12" 300W driver that goes up to about 3kHz and has an SPL of 102 dB @1m and 1W.
    Please recommend a tweeter!
     
  2. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    It all depends what type of tweeter you use. Piezo's don't need a crossover in theory, but I tend to use one anyway. Generally the overall nominal impedance of the cab remains unchanged. This is because actual impedance is frequency dependant. Tweets, especially those behind a crossover operate in the frequency range where the woofer is not running anywhere near nominal impedance.

    Where the tweeters' nominal impedance does matter is when designing/choosing the crossover. Compression horns have a nominal impedance, as do pre-fabricated crossovers. So if you put a 4 ohm horn on a crossover designed for 8 ohms, the crossover point will be knocked out of kilter.

    That's really all the theory you need to know. You may want to consider an L-pad so you can turn the horn down if it's too loud. Other than that, it's just a matter of buying a horn, a flare, and screwing it in. Wire it in parallel and you're done!
     
  3. Bruce Lindfield

    Bruce Lindfield Unprofessional TalkBass Contributor Gold Supporting Member

    How about a pair :

    [​IMG]
     
  4. jock

    jock

    Jun 7, 2000
    Stockholm, Sweden
    :D
     
  5. jock

    jock

    Jun 7, 2000
    Stockholm, Sweden
    Thanks Pete!
    Do you have a tweeter to recommend?

    Whats the deal with the tweeters Accugroove use?
    Silkdome or something? They seem to be really inefficient.
     
  6. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    Silk domes are more common in home Hi-Fi than Pro Audio. They sound "nicer" which is why that work well for recorded music playback. They're not normally associated with high SPL applications so I'd say Accugroove has designed them specifically.

    As for recommending a tweet, that's a hard one. I've got 5 cabs, some I bought and some I made. They all have different tweeters that all work well. I'm finding it hard to pick a favourite so maybe I'm not that fussy with horns. My horns don't actually do much until I start slapping, so as long as I can hear some sizzle on the pops and some chunk on the thumps, I'm happy.

    I've even found that CST (formerly motorola) plastic piezos do the trick. I know that Epifani use P.Audio horns. The horn on my Eden cabs sounds great, much better than the horn on my Nemisis. A lot of guys on here like the Foster horns that Avatar use.