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Im worried about the extreme limit of my Tumult...

Discussion in 'Home Theater Projects' started by ClaudeL, Jan 9, 2004.

  1. ClaudeL

    ClaudeL Well-Known Member

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    Hello,

    It is so hard to find the extreme limit of the Tumult woofer because it sounds so clean!!! I have for it a QSC PLX2402 amp and it seems to me that the amp clip before the woofer can bottom out (I measured the woofer excursion with a ruler). So now Im confused... when I begin to see the red LEDS flashing on the QSC amp (indicate clipping), I hear a kind of very noticable "TICKK" noise. I wonder if this is really the voice coil hiting the back plate or this is the sound you hear when the amp clip. Im so confused with that wonderfull woofer :b , how do you know if the voice coil hit the back plate? How different is the sound (clipping/voice coil hit)?

    Thanx for any explanations! [​IMG] Im sure that some users such as Brian know how to differentiate the sound of a voice coil clacking or an amp clipping in the case of the Tumult.
     
  2. Brian-K-Owens

    Brian-K-Owens Well-Known Member

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    Different Brian . . .

    Do you use the clip limiters on the PLX amp?

    Do you have that amp running mono on a single Tumult? If so, and you are seeing red lights on the meters, I would think you are risking damage. 2400 watts, right? That is beyond thermal limits of the driver.

    I have watched the drivers out of the box doing break-in, and the cone hits the 12 spoke basket before the voice coil bottoms out, so that may be what you are hearing. If it hits the basket too hard, it looks to me as though it will eventually break the tensile leads that it is pinching each time it hits.

    I would turn her down just a bit if it was me. . . .I would not want to see red lights with that setup. . . .

    Brian
     
  3. GrahamT

    GrahamT Well-Known Member

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    If you want more output try a new placement or a more powerful amp. That thing is 700W into 4 ohms right? If the VC former bottoms out it sounds like a LOUD clapping noise in my experience. Clipping is more of a popping noise or maybe as Brian suggest it is hitting the basket. You must have a large room or poor placement if you reaching these limits.
     
  4. ThomasW

    ThomasW Well-Known Member

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    The Tumult is similar to the ScanSpeak Revelator midwoofers.

    They are so clean that they play louder, and louder, and louder, and then poof!

    As a result one should use common sense when operating them. So if you see red clipping lights, TURN IT DOWN!!!!!!!
     
  5. ClaudeL

    ClaudeL Well-Known Member

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    Im running the amp in BRIDGED Mono mode... so yes, 2400W of power! [​IMG] But that 2400W shouldnt be harmfull for the woofer, because it is not continuous. For example, in a boom boom song (techno like), if that 2400W is really used, it is used on each "boom" hit.

    And yes, the amp clip limiter is activated.

    Brian, what you told is very surprising... the cone would hit the basket before? [​IMG] Wow!!! How much big was the cone excursion in that time? But now, more I think about it, more I think that its the amp which is clipping that I hear each time. Because I just turn down the volume A LITTLE BIT before seeing the red lights, and the "TICK" sound is gone. Still, Im very curious to know how big the woofer excursion is when I hear that sound.

    For the recommandation which indicate me to turn it down, I DONT WANT! [​IMG] Me want more bass!!! No but... I know, this is what I do. And I think that the sub is really well placed, this is where the Tempest was before. STILL, and some of you know this, if you read some of my last posts, the air leaks problem is not gone. I will correct this tomarrow or next week, when the new gasket will be bought and also, when the finish will be applied. If Im correct, air leaks reduce the sensitivy of the subwoofer, so later, before seeing the red LEDS, the woofer excursion is supposed to be higher. I really think that the woofer excursion never exceeded the 60 mm mark, I often measured with a ruler (something sticked to the dust cap permited me to read how much long).
     
  6. ThomasW

    ThomasW Well-Known Member

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    If you actually believe this statement; I suggest ordering your replacement driver soon, so as to have it in hand when you blow-up your existing one.....
     
  7. Richard Little

    Richard Little Well-Known Member

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    We've covered clipping and bottoming out, how does one blowing up sound?
     
  8. ThomasW

    ThomasW Well-Known Member

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    Figure of speech meaning melting of the VC. It's really not all that noisey, but the smell is terrible.....

    Although rare in certain circumstances the cone itself can literally be blown into the room... [​IMG]
     
  9. Brian Bunge

    Brian Bunge Well-Known Member

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    Well, when you only fry one of the two coils, you still hear bass, but there's a clanking sound accompanying it too!
     
  10. ClaudeL

    ClaudeL Well-Known Member

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    Well, Seth_L in this forum uses the same amp than me, and he started using his Tumult way before me... he doesnt seem to have any problem so far yet with his woofer. If you do a search, I think that you can find the time when he said that the thermal limit of 1600W was for ONE continuous hour, and 4800W for one second.

    And Brian (Bunge), I know you fried one... or a few Tumult??? with a powerfull amp. How much power during how much time??? Continuous? How did it happen?
     
  11. Brian Bunge

    Brian Bunge Well-Known Member

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    Claude,

    No, I only fried one Tumult![​IMG] I was using a Crown K2 bridged (2500W) but was also using an LT circuit which was boosting the low end quite a bit. This happened about half way or so through the Pod Race scene. As Thomas stated, it kept getting louder and louder and then finally...clank, clank, clank. [​IMG]
     
  12. ThomasW

    ThomasW Well-Known Member

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    Yes in THEORY that's correct, but in the real world DON'T try it or you'll smoke the driver, I guarantee it.

    In the long run it would be much cheaper to buy and use a second driver if you really really need more output!

    Also you're going to be sorry if you toast your Tumult; and find that it's NOT covered under warranty given the abuse you're subjecting it to........
     
  13. ClaudeL

    ClaudeL Well-Known Member

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    I already think about making a vented enclosure this year, certainly before the summer time, so I'll get more bass power without buying another woofer (I mean in the low bass region). I wanted to try a sealed Tumult first, just to know how it would sound and by curiousity because I didnt own so much sealed subs in the past. For the moment, I try as much as I can to not see the red LEDS [​IMG] I hope a lot that I will gain some dBs when the air leaks will be gone away, once I'll really finish the sub this week. [​IMG]

    A big thanx for all what you said to me! [​IMG] [​IMG]
     
  14. Seth_L

    Seth_L Well-Known Member

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    Claude,

    You are correct, I have a PLX2402. From my experience your Tumult will be fine pending you only see the clip light briefly and on the most extreme peaks (like the DTS version of The Haunting). ThomasW is right though. If you need more SPL and see the clip light a lot get another driver and build another enclosure.
     
  15. Seth_L

    Seth_L Well-Known Member

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    It was my understanding these numbers are real, not theoretical. Putting 2400W into the Tumult for a fraction of a second during a massive bass hit isn't going to toast the VC.
     
  16. Jack Gilvey

    Jack Gilvey Well-Known Member

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    I think Thomas' advice on moderation in powering the Tumult comes under the "word to the wise" heading and, as such, apparently has limited application here. There's one way to find out the limits, and Dan has more Tumults if needed.
     
  17. Craig Treusdell

    Craig Treusdell Active Member

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    I've been thinking about the same type of issue.
    I currently have two Tumults running off a RMX2450, with 750 watts pere sub. I don't think I should ever have a problem, but I don't think I'll ever get the full use from the Tumults.

    So assuming a sealed box (Qtc ~0.7) and you don't drive the amp into clipping (or do but have the clip limiter turned on), which amp would come closest to utilizing the full potential of the Tumult but also make it very difficult to ever blow?

    I had thought about replacing my RMX with two PLX1602s, one for each sub, at 1600 watts each.

    Opinions?
     
  18. ClaudeL

    ClaudeL Well-Known Member

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    At first, I thought that 1600W wouldnt even be ENOUGH... and I see that this is quite the case, BUT over 1600W, you are over the thermal limit of the woofer. If you want the maximum of your Tumults, in your case, yes, two PLX1602 or another amp which can deliver near 1600W of power are well welcomed [​IMG]

    I often prefer to have more power than not enough, so its why I chose the PLX2402 EVEN if 2400W of power is above the Tumult thermal limit. I told to myself... if Im gonna use it properly, if I dont clip the amp every time, I am better with that amp. Im not the person who will clip the amp with a test tone!

    Still, I know that if you think about it seriously, Im not THAT better with that amp... how much dB's do I gain compared to a PLX1602... 1.5dB!!! But I feel better when I have more power! [​IMG]
     
  19. Craig Treusdell

    Craig Treusdell Active Member

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    I have had that opinion about always wanting more than enough power. But since the Tumult was released I have read too many horror stories about fried Tumults. This has caused me to take a step back and ask the forum if using amps that would have trouble cooking my subs but still get them to their limit would be the safest AND best solution.

    I had originally asked Dan Wiggins about designing a servo-feedback circuit just for this reason. Get the maximum output at all frequencies without the worry of smoking $1000 in a matter of seconds.
     
  20. Brian Bunge

    Brian Bunge Well-Known Member

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    I think with proper calibration you'll probably never have any issues with the Tumult. It's doing what I did, kept turning it up without any calibration (I was using an LT circuit as well), that causes one to fry the driver. Luckily Adire covered reconing under the warranty. I don't know if that was because I am a dealer or not. Also, I don't know that they'd do this if people were continually blowing drivers either.

    Nah, you don't want no damn servo control. That's like building a 500HP engine and then electronically limiting it to 250HP. What a waste of money.
     

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