. I could hear no difference in performance but the LM317 circuit ran warmer using the 18V supply and I could not see any advantage.
I mounted the LM317 on a small heat sink outside, on the back of the subwoofer cabinet. One advantage is that I can measure both the 15V and the 9.8V under load without opening the cabinet to do so … handy. I made no effort to reseal the subwoofer and I hear no difference in sound quality. That surprised me because I believed that this was a sealed sub when I started this project, only to discover that it was a ported enclosure later on. Now, I’m not an audiophile so you may well hear something (or not hear something) that I’m not aware of. But, to me, it sounds as good as it ever did.
Nice work, and glad it worked out for you too!
Please don't take this the wrong way, but let me give my point of view on two items (I use to be a sound quality judge, built many a woofer enclosure and I also have been in the industry since '89 and have repaired many a R1000 for forum members).
The sound output level of the unit is proportional to the input voltage to the amps, I have measures the output with the OEM 19 volt compared to the 12 volt (since so many try to use the 12v to power the whole thing) and you will lose output level/power using the lower voltage, it's even in the TI data sheet too. Even at 15v you will have a loss in total output, but it will not be as much as running it at 12v.
15 volts is almost 20% less voltage then what is called out. When you said you could hear no difference, do you mean in quality or level, the lower voltage will not effect quality but it will effect level. Did you run two R1000's side by side?
You may have gotten very lucky and the seal you broke acted like a gasket, but in most cases it will not. I seal them up very aggressively due to loose in sound quality and possible woofer damage. The woofer is custom made for this application, you have to have to seal it back up for the port to work correct. I have seen many an improperly sealed enclosure let the woofer flop around like a fish out of water. Not sealing the enclosure also effects the suspension since it's no longer dampened like it should be (like bad shocks in the car) and let the cone/voice coil bottom out and cause distortion too. Perhaps you don't have the power required to see this (since your using 15volts) but it can happen.
Once again, nice work and the bottom line is all that matters, if your happy which you seem to be, then that is all that matters.
Roku3 and Roku HD1000 [Rev B] on a Samsung HLP5674W DLP in the living room; a Roku2 and two Roku XS and a few SoundBridges.Win7; Kubuntu and XP via RT-N66U, E2000 and a switch or two. I own stock in Roku, it's just all in the form of hardware.Viva la Roku