To add some meat to what I've been saying so far, and in the context of what this thread is focused on, I thought I would throw in a little rundown here on some of the current "work" I'm doing on the HT setup, to shed a bit more light on what I think is relevant ...
For some months now I've been running without subwoofer, to prevent any cross interference between the two powered boxes (main case and powered subwoofer) from confusing the situation -- so nothing much was happening below 200Hz! This has allowed fine tuning of how cables are routed in the case, and the use of spacing and damping materials to be played with in the main unit.
Now reasonably happy, so time to reconnect subwoofer. First thing noticed, polarity of power to the bass unit absolutely crucial: originally it used one of those two pin mains connectors that can fit either way, long since discarded for hardwiring. If polarity now the wrong way, quality plummets dramatically. The only connection with the main box is a coaxial lead for the bass signal, also hardwired; there is no earthing aspect to the setup, in fact as soon as the signal enters the subwoofer it goes through a simple slide switch to allow the phase of the unit to be reversed; this of course is also bypassed.
Now, where exactly to pull in the power for the subwoofer? Separate outlet from wall, separate circuit, hardwire lead to main boxes power lead, before or after passive filtering in the lead, these all make large differences, each configuration needs to be checked out. Anyway, a quick play around shows hard wiring after passive filtering is giving reasonable results, will do for now.
Try how it performs over a day: typically it starts sounding a bit ordinary, builds up over a few hours, and then slowly goes off song. The latter is a typical digital malaise, which a lot of effort has to go into to sort out. Not bad, not bad, weakest link in the normal sense is the subwoofer, it has various subtle resonances, the whole box needs to braced, damped and stabilised on a more rigid surface, none of which have I done yet.
The interesting experiment yesterday was a James Galway playing flute, called Classical Meditations. Yep, just what it sounds like, the sort of recording you got for mum on Mother's Day, designed to sound good on any bit of rubbish that could play a CD. My wife uses it for doing a style of Chinese stretching exercises, so very familiar with it. But when the system is humming, it springs into life and becomes something special ...
So, put it on and my wife said it wasn't right, it needs to be louder. So I ended up very quickly running at maximum volume, my wife was enjoying it, it was loud but I felt and she agreed, that there was still something not quite in the groove and so I did the last thing I normally do now to optimise performance and disconnected completely the last bit of the cordless home phone setup, a couple of rooms away. Ah, that's it! Now the sound fully blossomed as Roger would say, we now had a full version of the "big sound", dynamic, intense, the string section in the distance now had the right richness and bite, etc ...
So that's the sort of thing I have to worry about, showing that even mediocre electronics can be pushed to become as sensitive to the environment as any high end gear. That sensitivity is both a boon and a curse, just as for expensive gear, because you are always chasing down the next weakness. As I have just determined, I am still having issues with radio frequency interference, the RFI/EMI Roger talks of. A headache, but the rewards when you get it right are great ...
Frank
For some months now I've been running without subwoofer, to prevent any cross interference between the two powered boxes (main case and powered subwoofer) from confusing the situation -- so nothing much was happening below 200Hz! This has allowed fine tuning of how cables are routed in the case, and the use of spacing and damping materials to be played with in the main unit.
Now reasonably happy, so time to reconnect subwoofer. First thing noticed, polarity of power to the bass unit absolutely crucial: originally it used one of those two pin mains connectors that can fit either way, long since discarded for hardwiring. If polarity now the wrong way, quality plummets dramatically. The only connection with the main box is a coaxial lead for the bass signal, also hardwired; there is no earthing aspect to the setup, in fact as soon as the signal enters the subwoofer it goes through a simple slide switch to allow the phase of the unit to be reversed; this of course is also bypassed.
Now, where exactly to pull in the power for the subwoofer? Separate outlet from wall, separate circuit, hardwire lead to main boxes power lead, before or after passive filtering in the lead, these all make large differences, each configuration needs to be checked out. Anyway, a quick play around shows hard wiring after passive filtering is giving reasonable results, will do for now.
Try how it performs over a day: typically it starts sounding a bit ordinary, builds up over a few hours, and then slowly goes off song. The latter is a typical digital malaise, which a lot of effort has to go into to sort out. Not bad, not bad, weakest link in the normal sense is the subwoofer, it has various subtle resonances, the whole box needs to braced, damped and stabilised on a more rigid surface, none of which have I done yet.
The interesting experiment yesterday was a James Galway playing flute, called Classical Meditations. Yep, just what it sounds like, the sort of recording you got for mum on Mother's Day, designed to sound good on any bit of rubbish that could play a CD. My wife uses it for doing a style of Chinese stretching exercises, so very familiar with it. But when the system is humming, it springs into life and becomes something special ...
So, put it on and my wife said it wasn't right, it needs to be louder. So I ended up very quickly running at maximum volume, my wife was enjoying it, it was loud but I felt and she agreed, that there was still something not quite in the groove and so I did the last thing I normally do now to optimise performance and disconnected completely the last bit of the cordless home phone setup, a couple of rooms away. Ah, that's it! Now the sound fully blossomed as Roger would say, we now had a full version of the "big sound", dynamic, intense, the string section in the distance now had the right richness and bite, etc ...
So that's the sort of thing I have to worry about, showing that even mediocre electronics can be pushed to become as sensitive to the environment as any high end gear. That sensitivity is both a boon and a curse, just as for expensive gear, because you are always chasing down the next weakness. As I have just determined, I am still having issues with radio frequency interference, the RFI/EMI Roger talks of. A headache, but the rewards when you get it right are great ...
Frank
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