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Speaker blown?

Discussion in 'Amps and Cabs [BG]' started by G Stilphen, Nov 2, 2018.


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  1. G Stilphen

    G Stilphen

    Aug 29, 2018
    I thought I blew a cab last night at rehearsal. The cab started sounding crappy after playing for an hour. I brought it home and now it seems fine. Can speakers be pushed too far and not actually blow? I have fried a cab in the past with the same head and I know that smell. No smell this time. The cab is a ampeg svt410.
     
  2. filmtex

    filmtex Commercial User

    May 29, 2011
    Annsman Pro Audio Dealer
    If you're really pushing a cab it's possible to get the voice coils hot enough to cause a speaker of speakers to sound crappy. Especially if they sound ok once they cool down. Best reason to take breaks at gigs and rehearsals. I think if you get them hot enough for a long enough time you'll find yourself in real trouble. Which 410 are you using, the (current) HLF is rated 500 w @ 4 ohms while the HE is 500 w @ 8 ohms. (Some of the older 410's had very different power handling capacity than current product. The BSE410H was rated at just 200 w @ 8 ohms.)
    You might have an impedance mismatch. What are you driving this with. Glad to hear that the smoke didn't escape though!
     
  3. G Stilphen

    G Stilphen

    Aug 29, 2018
    Thanks, The cab is 410 HE 8 ohms 500w. I just got the head which is an Orange TB 500w. I have read these things have power bursts up to 975w.
     
  4. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    I doubt that your speaker was damaged or even part of the cause of the symptoms.

    975 watts RMS or peak?

    Burst? It's possible, but I wonder if there's some terminology being mixed up here. 3dB of dynamic power is awfully high IME.
     
  5. G Stilphen

    G Stilphen

    Aug 29, 2018
    This is what I read:
    Bass Gear – July 2011-Issue 6

    The output power of this amp is where things really get terrifying. At four ohms, the amp was able to crank out 519 watts continuous, with a burst power of 972 watts (cue the theme music from Psycho). The amp handled dynamics and transients well under lab conditions. It does appear as if the non-defeatable limiter can really clamp down on the Signal, and the limiter appears to have been programmed with a relatively long release time, exhibiting a recovery that exceeded one second in our dynamic burst signal. Results from our burst signal test are illustrated in Fig. I.

    The amp also performed well in our gain tests. As the input signal was swept over a range typical of bass signals, the output and distortion products behaved predictably and linearly up to the steady state limits of the amp, as illustrated in our plot of distortion as a function of output in Fig. J.

    The preamplifier has a lot of gain on tap. With the Gain knob relatively low (e.g., round 9:00), the output exhibited a relatively clean signal with strong second and third harmonics. As the Gain knob was turned up, the distortion products increased significantly, as illustrated in our distortion product plots of Figs. K and L.

    One somewhat unique feature of this amp is that the output power is rated at 500 watts regardless of whether the load is 4 ohms or 8 ohms. How does Orange accomplish this feat? Through intelligent limiting. The power amp is definitely capable of putting out 500 watts into 8 ohms, and the impedance switch reprograms the limiter, or otherwise sets an arbitrary peak signal ceiling, when the switch is in the 4-ohm position.

    Our tests bear this out. With the switch in the 8-ohm position, the amp output about 500 watts at 8 ohm, with a burst of 637 watts. On the other hand, with the switch at the 4-ohm position, the amp output just over 500 watts, with almost 975 watts burst. The burst output is drastically different for different loads. Also, in our continuous power measurements, we recorded about 62 Vrms at 8 ohms, and approximately 45 Vrms at 4 ohms. Here, you can see that the amp is scaling back the maximum continuous output when the impedance switch is in the 4-ohm position.
     
  6. saabfender

    saabfender Banned

    Jan 10, 2018
    Indianapolis
    All this talk of bursting makes me want to pee. I think you mean “peak”.
     
  7. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Ahhh, the burst for 8 ohms (your condition) is 637 watts which is 1dB

    Because of what they are doing, I why the difference is larger for a 4 ohm load (a somewhat unique situation).
     
    saabfender likes this.

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