Ahhh. Now I know why your amp got so hot.
Movies have a shite ton of low frequency information in them and even though you probably turned the bass knob down, you very likely clipping the sub for two hours. This is the reason why it's important to set the gain on a subwoofer amp with a 40 Hz tone and a scope or distortion detector.
I agree with the frequencies,.. but not the clipping. I had the volume very low.. and the bass knob was down.. Voltages were not even close to the max rated RMS of the amp -- And the amp is running 30watts less than the RMS rating of the Sub. I'm playing it safe.
I'm dialing the sub in to the voltage for wattage,.. then backing down some. No, I can't be for sure I"m not clipping without a DD-1 or some such.. but that said,.. If the amp or especially the Sub died in a year or two.. It's not a big deal to replace them. Sub it $99.. Amp is $200... and the amp I'm going to work on a good cooling solution even though it's class D, so it will live a long healthy life.
When I said I shifted to a 79hz frequency.. I still shifted back to 40hz to see where the voltages were,.. I don't let voltages go higher than the RMS rating with the Bass knob on max. I have it set up to where no matter what plays,.. it's in the "safe" zone. (And, yes.. again I know I can't tell 100 percent without a DD-1 or O-scope.. but I've done all I can do to be "safe" as it were.)
Imma beat a dead horse here but.... the gain on your amp is not a "set to my music" device. It's a sensitivity matching device and it's there to make sure your amp and head unit are set so there is (virtually) never a clipped signal being created by the amplifier. By setting it the way you did, there is only one way to ensure that you never clip your signal and that way would be using a scope or distortion detector to find out exactly how far down you must turn the bass knob in order to match the amplifier's sensitivity with the source.
That's precisely how I have set it .. Safety first.. I honestly do not think I'm clipping at all with every Channel backed down 1-2v from the the 4 Mids and Highs .. Voltage = Sqrt(70wx4ohms).. and Sub running 2-3v behind the Voltage = Sqrt(270wx4ohms).
I almost forked out $150 for a DD-1 just to test.. but that'd be silly really. If I end up blowing an amp or something.. then I probably will to prevent equipment failure in the future,.. but I have it set quite conservatively.
Now with all that said, I'm not saying you're going to be roasting coils on a regular basis but, it's important to note that your gain is not correctly set and if you leave it that way you will be clipping your sub more often than you may think.
In the end, if the system is properly set up and there's just not enough bass... you can't simply fool mother nature and set it by a different method. ;-)
Oh, remember my goal was to have the equivalent of a factory premium OEM system .. you know those systems that have a free air 8" sub , etc? Trust me .. I have MORE than enough bass lol. I really think you guys would be very, very impressed with the sound quality and amount of bass from this install, and Single 10" JL sub in a .66 Sealed enclosure running at a mere 270watts RMS (max)..
It's EXACTLY the sound I was after.. X 100 -- Extremely clean, tight,.. and I spent an hour today with a USB stick of 2 dozen frequencies and Octave rollovers, etc.. Dialing in the amps Crossovers on the Front, Rear, and Sub -- (The headunit has Front, Rear, and Sub active X-over as well.. but the amp comes first.)
I was listening to the attenuation as the tones played while twisting.. and really dialed it in. I also hooked up my DMM to the channels and watched the voltage drop as it hit the Cross-over points while watching the headunit for the Hz that was playing to correspond with the drop. Was actually quite interesting to do.. Before I thought Crossovers just CUT the signal at X frequency.. but it's X dB attenuation of course.. and really shows itself when you spend some time isolating speakers.. ie: I had just the sub receiving input for a long time.. the sub took the longest to dial in the Amp's X-over. (Remember this PPI amp has a min and max value.. so you are blind and have to go buy what you hear,.. and the DMM's voltage shifts which are steady and you can tell exactly where the X-over point starts with the first subtle drop in voltage.. that drops rather quickly past the X-over frequency.
It was a learning experience. I noticed that while I was shifting between min and max on the sub (40hz to 220hz).. that even if I had it set to say,.. minimum 40hz x-over low pass for sub.. I could play a 125hz tone and you could still audibly hear it. Now,.. playing a 1000hz tone you couldn't hear of course.. but the attenuation spans a larger range than I thought it would, which helps you understand how the sub is going to react precisely. Hard to put into words, but I'm sure you know what I'm talking about.
But, man I have this thing dialed in absolutely perfect to *my* ears,.. and it's so killer.
Again, with the movie playing.. I had the bass knob at 1/4,.. and volume at 10 (Max is 35).. So the amp was heating up due to zero venilation in a carpeted area.. playing a wide range of tones during the movie I suppose for about 3 hours (car was off the whole time.. not that, that makes a difference in amp temp.)
---------- Post added at 08:40 PM ---------- Previous post was at 08:39 PM ----------
its awesome... i use it ALL the time depending on the song. heres how my setup looks, the 2 blue dots on the bottom are my crescendo bass knobs
Sweet setup man!
