Originally Posted by LTD02
sorry to hear about your drivers guys.
here is 1000 "watts" through the si18 in a sealed enclosure.
the actual current through the driver dips around 40hz because that is where the resonant frequency is in a smallish sealed cab. at that point, current is minimal. then it begins to rise again, but an 80hz low pass filter then reduces it down and by 200hz, it's pretty much zero.
as you can see, down under 10hz, the driver is almost purely resistive. in other words, something like 99% of the energy going into the coil must be turned into heat. at 1000 watts, that is about 990 watts of heat. pretty much like running a hair drier and putting your hand over the end so that no air flows. it will heat up REALLY FAST. unfortunately, most hair driers have thermal circuits, subwoofers do not.
that test track is a stupid test track. it runs a constant signal starting at 1hz and going up from there.NOBODY SHOULD TORTURE THEIR SUBWOOFERS WITH SUCH A TRACK.
this is just an extended duration heating of the coil until it blows. i'm not surprised at all, though i feel for everybody who didn't know better.
the spectrogram doesn't even look like content. it is just full power single digit torture.
the s.i. subs may be chinese low quality drivers, but this track is just abuse.
as for the berry output, 1000 watts is probably about what you were seeing.
Ltd02: I have read many of your posts and respect your knowledge and opinions, and it seems that you seem to enjoy helping people and sharing your knowledge. I would appreciate a bit of your time to help me understand a few of the concepts that I apparently don't grasp.
First, What programs are you using for your charts?
Then, I Don't understand what you are trying to show by your 2 charts here.
For the first one:
I get that the impedance rises at resonant frequency, therefore the dip in power output. It seems to show that you can get a steady amount of power output to a sub at low frequencies.
For the second:
I have no clue what this is trying to show. Could you explain, or just give the program name so I can learn it for myself.
Can you compare the "Bassnectar The matrix" track as a comparison to this track? This Is typical of music I enjoy, and want to make my system "bulletproof" from for hours at a time at high levels, even with dumber people than me with my remote. I don't think it is too far off, other than being a bit higher frequency.
For your hair dryer analogy, I think this is pertinent to this situation. I can turn my hair dryer on LOW and cover 75-90% of the airflow and it will run hotter than normal but for the long term. I am thinking if you have a steady amount of wattage going into a sub then there should be a point of maximum cooling at higher relative frequencies while still having large cone excursions (fast hard fan). So I can understand how putting more than the recommended wattage into a low frequency would "let the smoke out".
How do you get that 99% of power is turned to heat under 10HZ? Is that not OK? Assuming it is less than the rating of the driver? I was under the impression that power sent to a speaker was dissipated as heat regardless the frequency, hence a continual power rating.
Why would you assume/calculate that 1000 watts/channel was what I was sending from the "berry"-behringer ep4000 when my killawatt read 1505 watts at most for the total input, not Volt amps which could be a slightly inflated rating because of PFC as I just read up and understand it. I can measure total voltage with a multimeter, I think I have a fluke laying around, with another shorter test on my remaining sub to put the issue to rest I think. But I thought calculating steady state output was just simple algebra with leaving peak output and capacitance added output of the amp out of it.