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15w 288-8k driver with 60w?

Discussion in 'Speakers' started by bryans12v, Apr 20, 2017.

  1. bryans12v

    bryans12v Marantz Junkie Subscriber

    Messages:
    1,180
    Location:
    Hudson Valley, NY
    I apologize for such a stupid question but I have recently come across a pair of Altec 288-8kvcompression drivers and Manta ray horns. These drivers have only a 15w power handling capability.

    I'd really like to be able to drive these with my Dynaco mkiii's is 60w too much for them? I know if they were low freq woofers this would not be much of a problem but I'm very new to compression drivers and don't want to harm them.

    For what it's worth, I listen at moderately low listeling levels for the most part.
     
  2. elitopus

    elitopus Super Member

    Messages:
    2,125
    Location:
    Saint Augustine
    The power handling changes with the xover frequency. The higher the xover, the higher the power handling.
    Also 15-20 watts on a really sensitive driver is pretty damn loud. I bet you never put that much power to them. Probably 1-2 watts at most.

    What midbass cabs do you plan to use these with?
     
    jwrauch likes this.
  3. BillWojo

    BillWojo AK Subscriber Subscriber

    Messages:
    1,976
    Location:
    Burlington, NJ
    If you listen at moderately low levels your not going to hurt them. At 15W your going to be begging for mercy. What are you using for a crossover? Don't feed them a full range signal, the high energy LF may burn up the voice coils.
     
  4. bryans12v

    bryans12v Marantz Junkie Subscriber

    Messages:
    1,180
    Location:
    Hudson Valley, NY
    Thanks guys! I'm still searching for a decent crossover. I've spent months reading about the Ashley and beringers and still have not pulled the trigger. I currently have a really clean pair of Valencias 846Bs and the initial plan was to biamp them with an active crossover. Now that I have the horns I may be looking to tramp and have the 806-8as in the cabinet working high fq as the 288s cutoff at 15k.

    I really like the idea of being able to adjust on the fly with those crossovers and may jump on a pair of Ashleys. I may add a pair of bass cabs next to biamp with the 288/horns and have the Valencias to the outsides of them.
     
  5. bowtie427ss

    bowtie427ss arigato gozaimashita Subscriber

    Messages:
    16,156
    Location:
    Land of Milk & Honey Boo Boo
    At 8 watts in you'll be approaching 120db. They will clearly demonstrate the noise floor of any amplifier you connect them to as well as the noise floor of your upstream equipment.

    To begin to explore their full potential you'll need midbass and LF more substantial than the bottom half of an 846.

    I wouldn't bother trying to run an 806 in conjunction with a large format driver, they have similar HF roll-off characteristics, and the 806 is a decade of db's behind in sensitivity, it'll be smoking to try to keep up with 1 watt of 288 input. You'll need a real compression tweeter(or several) that approaches the 288's sensitivity to keep up.

    Until you become intimately familiar with any set-up you connect them to, use a series cap of good quality to protect the 288's from LF content of both improperly set networks, AND turn on/off transients from your amplifiers. You might still get a substantial audible "pop", but a series cap valued such as to have a knee point an octave below your intended crossover freq will snub harmful LF content of such transients.
     
  6. twiiii

    twiiii Super Member

    Messages:
    4,110
    If you cross above 800 Hz as I have with a pair mounted on a wye throat on 1 channel of a Mac 2120 with power guard in Bars, Cantinas, and discos and never had an issue. Another choice is a Mac 2120 2150 crossed at 1200 hz using the N-1201 8a. Of course passive crossovers knock the level down 4 to 6 db when using A-7 bottoms and even more when using ported boxes maybe as high as 10 db depending on the woofer choice. MY favorite old horn was the 311. Manta rays work well for dictional control for PA work, but they really spoil HF output hove 9 KHZ, where a 311 is smoother and much more musical. manta ray has two acoustical centers, one for the horizontal and one for the vertical, where multi cells have just one and are easier to use with complex distribution patterns. But with all that and the problems with sectoral horns I still like the 311/ Using a throat adapter with smaller horns just doesn't do it for me. Back in the old days the 288C diaphragm was rated at 40 watts and that was very optimistic. I guess they figured the impedance mis match allowed this rating.

    As for a super tweeter if you want to be really exclusive and envied by everyone, you need to find a pair of UHF 950 Altec ring radiators. It does everything right that JBL wanted to do with their attempts. Other wise you'll have to settle for MR 902 Altec. There maybe some european HF tweeters that will work, but I have no experience with them.
     
  7. gdmoore28

    gdmoore28 Super Member

    Messages:
    1,012
    Location:
    Central Arkansas
    The other guys have given you some great advice. As Bowtie pointed out, pairing the 806s and the 288s will be a total waste of time, since both have the same hf rolloff characteristics. Nothing to be gained.

    I wish I'd saved a tech paper that I found last week in which JBL discussed the advantages of 2" vs 1" horn drivers. Now I can't find it. But, the most memorable upshot from the article was that their 2" drivers have only 25% of the distortion of their 1" drivers. And similar hf extension.

    As noted, the only ways to get additional hf extension in your system is through extreme eq or adding a super tweeter.

    Will be watching your progress.

    GeeDeeEmm
     

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