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Discussion in 'Amps and Cabs [BG]' started by sheepdip, Aug 3, 2004.

  1. sheepdip


    Apr 14, 2004
    Well, the speakers are 99% completed. The 15's sound nice but the 18 leaves something to be desired. I don't have a crossover in it yet and it sounds gravelly and buzzy. It's hard to explain, the the presence isn't there. I double checked the hookup. It's newly reconed and I can't see any problems with the coning. any ideas????????? :meh:
  2. 4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge
    Never heard an 18 with much 'presence'. When I think presence, I think of the classic JBL 15, aluminum dust cap sound. 18'd, even JBL's don't do that. They do go rumble thump real well.

    How are you powering that setup? with an 18, I'd be inclined to biamp ...
  3. sheepdip


    Apr 14, 2004
    Well, The 15's sound a heck of a lot better than the 18 thats for sure but I am not getting the deep rumble bump from the 18. I don't have the bucks yet for an amp and just hooked my Crate 10 0r 15 watt practice amp up to it (I hate to even admit to that) to see what they sound like. Like I said, there is some garbage coming thru the 18 that is not there on the 15's. a buzzing in the background on ea. note. The 15's are JBL D140F's and the 18 is a JBL 2245H. :crying:
  4. Mike Money

    Mike Money Banned

    Mar 18, 2003
    Bakersfield California
    Avatar Speakers Endorsing Hooligan
    Maybe it sounds like ass because of the whopping 15 watts you have running through it?
  5. Schwinn


    Dec 4, 2002
    Sarasota, FL
    also check that it is firmly screwed in and that the edge of the speaker isn't rattling against the cabinet. I can see if the speakers are mounted directly on the wood, but if that is the case, you may need to have something like felt/cloth to create a better seal between the speaker and the wood. And, you've probably already done this, but look for any abnormal movement around the cone and the dust cap.
  6. Schwinn


    Dec 4, 2002
    Sarasota, FL
    by the way, nice looking cabs!!
  7. sheepdip


    Apr 14, 2004
    Thanks for the cab kudo. I don't think the ass whupping 10 or 15 watts is making that sound thru the speaker, maybe no volumn but not the other stuff (could be wrong though) Rechecked the solder joints at the 1/4 phone jacks (input and output) and I have a rubber seal between the speaker and the cab and checked the tightning on those screws. Doesn't seem to be anything wrong with the cone and dust cap. The 2245H doesn't have a metal dust cap like the D140F. This has me stymied thats for sure. Wish Zzounds would put a few Ampeg SVT CL's on their 'scratch and dent' sale so I could afford a decent amp.
  8. xyllion

    xyllion Commercial User

    Jan 14, 2003
    San Jose, CA, USA
    Owner, Looperlative Audio Products
    Don't know what the source of your noise is, but I'd like to say that I think you did a great job on those. 2x15 rocks!
  9. sheepdip


    Apr 14, 2004
    Thank you! I down loaded the speaker cab dimensions from the JBL site and used their specs for the cabs. I put wheels on the rear bottom and a handle upper rear back to I could tilt them and roll them around. I was suprised at how well the 2x15's sounded with just the little practice amp.

    BTW I decided to order a 5mh inductor and 40uf cap. I'm going to build a crossover for 350hz for the 18 and see what that does.
  10. Those are classy lookin cabs man! I've got a cab question. Is there any way to wire a 4 ohm cab that has 2 16 ohm drivers and 1 8 ohm driver back to 8 ohms?
  11. sheepdip


    Apr 14, 2004
    Possibly but I'm not sure. I think if you wire the two 16's in parallel to get 8 ohms and then wire the single in series with them you would get a total of 8 ohms but don't quote me. :meh: :meh:
  12. Petebass


    Dec 22, 2002
    QLD Australia
    Nope, that bring it back to 16 Ohms. You can wire up all 3 speakers in parrallel and get a 4 ohm load. Those are you two main choices.

    Lets pretend that the 16 ohm speakers are 10's (or anything small) and the 8 ohm is a 15 (bigger). You can get an 8 ohm cab by putting installing a crossover. Correctly done this willl take the nominal impedance of the smaller speakers out of the equation. I don't know if it'll work in this case though...........

    I'm not sure what might be wrong with the 18. I'll have a better look at it when I get some time.
  13. Rock&Roll


    Jul 21, 2002
    Not trying to get too far off topic, I once powered an 18" Acoustic folded horn with a 12-watt Marshall lead twelve. Sounded good, and got a lot louder than I though 12 watts ever would, without distorting. This was just a temp thing for bedroom use until my power amp got fixed. But in this case, it's a crate. 100,000 watts isn't going to help a crate.
  14. The JBL 2245 requires 7.5 to 9 cubic feet for optimum volume.

    What is the tuning frequency? I ask this, because I don't recall seeing any JBL plans with a lot of ports. The correct method of port calculation is dividing the total internal volume by the desired number of ports. Calculate each port length and diameter to tune that division of volume.

    A mis-tuned cabinet will not buzz at low power... it just won't sound right. You say the 2245 was recently reconed. Was a genuine factory kit used? If not, all bets are off for the driver being close to the factory T/S specs. Who did the recone job? Is the voice coil rubbing?
  15. sheepdip


    Apr 14, 2004
    JBL enclosure guide for 2245 10 cubic feet, vent area 75.4 sq in., 6 duct tubes, 4 in. id and 15.2 in. long. Straight from the JBL vintage site.

    I bought the spkr on E-bay from a reputable speaker dealer whom I have done business with before. I got the darn thing so long ago, 8 months I guess that I will have to go thru the paperwork and find the dealer. I could probably just go to e-bay and look until I find them. They sell a lot of JBL stuff. The voice coil does not appear to be rubbing.

    I went and look up the dealer.....Total Audio in Kansas City. I am going to call them in the morning.
  16. Using 4" PVC with an ID of 3.998", and length of 15.2 inches, I get a tuning frequency of 33 Hz.
  17. I've had problems with improperly seated dust caps causing buzzing (esp. after a recone). On some cheapo speakers I'd just cut the dust cap off, but you probably wouldn't want to do that w/ these JBLs.

  18. sheepdip


    Apr 14, 2004
    What is this telling me other than what I need to crossover at