Need help with speakers

Discussion in 'Amps [BG]' started by tahbass, Mar 13, 2014.


  1. tahbass

    tahbass Supporting Member

    Joined:
    Apr 9, 2009
    Location:
    Park City, UT
    I blew up my cab at band practice tonight. It's a custom built Emperor 4x12 rated at 600w at 8 ohms. I popped the cab open to see the speakers and they were all Eminence Alpha-12A. Two of them were hot to the touch and had a burning smell about them. After testing the speakers to see if they were putting out anything, I have concluded that the speakers are 100% kaput. I was using a Aguilar DB750 and several pedals plus a Musicman Stingray and the cab just stopped making sound.
    With all that being said, I have a small tour coming up in three weeks so I need to get some new speakers fairly quickly. What are your recommendations for replacement speakers? I'm not particularly inclined to use the same speakers for fear of the same thing happening again. Maybe a higher wattage rating...? I'm not sure! Please help!
  2. orangejulius3

    orangejulius3 Supporting Member

    Joined:
    May 6, 2013
    Location:
    La Habra CA
    I would recommend the GK NEO 412. You just might like it.....A LOT!
  3. tahbass

    tahbass Supporting Member

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    Apr 9, 2009
    Location:
    Park City, UT
    Not looking to get a whole new cab, just new speakers for the one I have. Does GK sell the speakers on their own?
  4. DukeLeJeune

    DukeLeJeune Only immortal for a limited time Gold Supporting Member

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    Owner & designer, AudioKinesis; Auth. mfg, Big E (Home Audio only)
    What are the approximate internal dimensions of the cab?

    Is it ported or sealed?

    If it's ported, can you give us the dimensions of the ports?

    If it's sealed, how do you feel about converting it into a ported box, perhaps by adding ports to the side(s) or back of the cab? You see, woofers that have medium to high power handling tend to be much better suited for use in a vented rather than sealed box.

    What sort of budget do you have, and how important is weight?
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  6. tahbass

    tahbass Supporting Member

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    Apr 9, 2009
    Location:
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    It's 18" deep by 2.5 ft wide by 4 ft tall approximately.

    It has ports on the front lining the bottom of the cab, three that are rectangular in shape. I'd say the ports are probably close to 2.5"x6"

    Budget isn't too much of a concern, since I need an amp and want it to sound good. Need it to be loud to compete with two guitar players playing through 100W tube amplifiers. As far as weight... "you know it's a good piece of gear if you poop blood while carrying it"
  7. DukeLeJeune

    DukeLeJeune Only immortal for a limited time Gold Supporting Member

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    Nov 24, 2008
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    Owner & designer, AudioKinesis; Auth. mfg, Big E (Home Audio only)
    Thanks for the additional information.

    One more detail, if you don't mind: WHat's the depth of the ports? That's part of what goes into determining their tuning frequency. Or is the port depth just the thickness of the plywood (presumably 3/4")?

    I love your method for determining what's a good piece of gear!
  8. tahbass

    tahbass Supporting Member

    Joined:
    Apr 9, 2009
    Location:
    Park City, UT
    I'd like to say the port goes back about 6-8" then there's a piece of grill cloth. after that, the openings for the port feed into the main enclosure for the cabinet.

    Thanks! It's a fool proof method.
  9. JimmyM

    JimmyM Supporting Member

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    Apr 11, 2005
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    Apopka, FL
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    Endorsing: Ampeg Amps, EMG Pickups
    Delta 12a's. 400w power handling, will sound better than the Alphas, won't break the bank, should work fine in your cab.
  10. DukeLeJeune

    DukeLeJeune Only immortal for a limited time Gold Supporting Member

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    Owner & designer, AudioKinesis; Auth. mfg, Big E (Home Audio only)
    Okay, Emperor did what I would have done with the Alpha 12A.

    The Alpha 12A's characteristics (T/S parameters) make it well suited for a sealed box, but not so much a ported box, however we can put it in a very low-tuned ported box and get some increased in performance over a sealed box. They've tuned the box to about 31 Hz, the fundamental of low-B, which reduces its susceptibility to fartout relative to sealed box mode.

    So as we look at woofers that have higher rated power handling, that's only moving the burnout threshold of the woofer. The fartout threshold is a function of the linear excursion (x-max) of these woofers, so I've indicated how much louder they'll go before fartout.

    There aren't all that many woofers with as much top end as the Alpha 12, so our choices are limited if that's a priority. Top end extension is one of the things we often trade off when we increase the thermal power handling and/or excursion capability (how loud it will go before fartout). And of course the tone will change, maybe for better, maybe for worse, so be prepared to change your tone control settings.

    The Beta 12A2 will work well in that box. It's rated at 250 watts, so not a huge increase in power handling, but an improvement nonetheless. The Beta 12A2 should go about 4 dB louder before fartout, but remember you'll be heating those voice coils up hotter to get there.

    The Delta 12A has as much if not more top end energy, but no more excursion than the Alpha 12A. Of course it has much higher thermal power handling, so you're less likely to burn it up. But you'll have to crank in a fair amount of low-end EQ to get back to the warmth of the Alpha 12A. (Good call, Jimmy! I bet you didn't even have to crank up your modeling program!)

    If you really want to up the thermal power handling, and be able to readily demonstrate the quality of your gear to anyone who dares question it, the Delta Pro 12A is a candidate. You're probably not going to burn up a quartet of those. Unfortunately you'll have to crank in a fair amount of EQ to get the low end warmth of the original Alphas. Once again, expect to go about 4 dB louder before fartout, and this time your voice coils can take the extra power.

    I like the frequency response curve of the Beta 12A2 best. The Delta 12A will probably come the closest to replicating the performance you have now assuming you crank in some EQ. If you want louder before fartout along with higher power handling, go with the Delta Pro.
  11. Arjank

    Arjank

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    Oct 9, 2007
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    That's common practice with such type of drivers, the port acts more as a excursion-limiter then an efficiency-enhancer. The problem is that when the voice-coil heats up the Qes changes a lot with these high-Q drivers and as a result the tuning is "off" at higher volumes.

    The fart-out threshold will actually be a bit lower even if the xmax is the same, that's because the voice-coil won't heat up as much so the Qes stays approx the same and the cabinets/driver tuning doesn't wander "off" as much at higher volumes. Which means you have better mechnical control over the driver. That's what the simulation programs don't tell you...

    +1
    That's a good choice if I look at the TSP's and response chart, also really well suited for ported cabs and the xmax is ok.
  12. Vince Klortho

    Vince Klortho

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    Jan 8, 2013
    Location:
    Squierville, California
    In my opinion, you have at least two ways to go. One is to replace the speakers and Duke has given you some very good options. The problem is you should replace all four of them and that can get expensive. Another option is to find a different cabinet, possibly used to save some money. The cost of the used ones I like will be less than four new speakers. Those would be cabinets like the Hartke 410XL or 4.5XL. For a bit more money you could try a used Eden cabinet. Of course, there are many other possibilities but those are the ones I am most familiar with a like a lot.

    I did read that you do not want a new cabinet but if you are going to get different speakers then you will effectively have a new cabinet. The sound is not going to be the same as it was.

    That's just my opinion. :)
  13. Grissle

    Grissle Supporting Member

    Joined:
    May 17, 2009
    You may not realize there's science involved between the speakers specific parameters and the cabinet design. Just buying some nice speakers and bolting them into a cabinet is just spending money and hoping you luck out.
  14. JimmyM

    JimmyM Supporting Member

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    BWAHAHA!!! Like I could understand it if I had one ;)

    The brighter top end is why I figured the Deltas would work well and I figured the low end would be approx the same as the Alphas, or like you said, just need a little low end bump.
  15. tahbass

    tahbass Supporting Member

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    Apr 9, 2009
    Location:
    Park City, UT
    +1. I know... it sucks that it will be pricy but I'd rather try to find a similar sound (possibly one I might like more?) with the same cab instead of switching to another that might be less appealing both in sound and/or aesthetics.

    All four speakers blew though, not a single one was putting out anything measurable when tested with a volt meter.
  16. gary m

    gary m

    Joined:
    Jan 17, 2011
    Location:
    Mid -Atlantic
    Another vote for the Eminence Beta...I've used these as replacements in the past and have always been satisfied with them.

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