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

ClaudeL · 01-09-2004, 04:03 PM

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!

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.

Brian-K-Owens · 01-09-2004, 04:15 PM

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

GrahamT · 01-09-2004, 06:01 PM

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.

ThomasW · 01-09-2004, 06:03 PM

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!!!!!!!

ClaudeL · 01-09-2004, 06:22 PM

Im running the amp in BRIDGED Mono mode... so yes, 2400W of power!

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?

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!

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).

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ThomasW · 01-09-2004, 07:18 PM

Quote:

But that 2400W shouldnt be harmfull for the woofer, because it is not continuous.

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.....

Richard Little · 01-09-2004, 07:48 PM

Quote:

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.....

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

ThomasW · 01-09-2004, 09:12 PM

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...

Brian Bunge · 01-09-2004, 09:23 PM

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

ClaudeL · 01-09-2004, 10:31 PM

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?

Brian Bunge · 01-09-2004, 10:38 PM

Claude,

No, I only fried one Tumult!

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.