beating the beat frequencies
OK, I finally got rid of some of the annoying digital hash sound. Remember "one path to ground"?
The XV-88's pre-amp module is attached to the case via two metal brackets that aren't tied to anything else on the circuit board, but when I remove the pre-amp module from the case and break this connection - Walla! the annoying tone disappears!
I replaced the metal screws with nylon and screwed it back in. Bad sound still gone. I took a sample of the sounds again - there's still noise down there at -82 db but the two channels of it are now in phase
. Connect the pre-amp board with metal screws - out of phase - with nylon - in phase. Weird.
There's still this 4 second peak in the noise that must be coming from RFI somewhere, but what? 2.4 ghz wireless? 800mhz phone? Space aliens?
I've spent so long at this hideously low volume that I can clearly make out the sound of my laptop plugged in and not, the sound of a LCD display, and the sound of an old USB hub's wall wart (tossed).
Kvetch - there must exist some sort of rack mount "wall wart eliminator" - something with like 6 normal 3 prong jacks and a set of, like, 8 terminals for DC devices, switchable from 1.5v to 12v, 1000ma. It's nuts to have a half dozen DC transformers in a situation like this... Juice goose used to make one
- with a weird cabling scheme
- all I want would be regular wire, screw terminals and connectors that interface to Radio Shack's standard line of DC adaptor connectors.
I am surrounded by the guts of the XV-88 as I write, in addition to the totally dissassembled rack's worth of cables and gear. I should really reassemble it, but I want to take some pictures first... I think I've only fixed a symptom of the problem, for a while I thought I'm going to order a new cpu board for the thing - or maybe a new power supply - or a pre-amp - choices, choices - now I'm playing with . Linuxsampler
and I'm thinking I'm going to abandon the sound modules on the XV-88 entirely in favor of doing it all pure digitally... if I can find a piano sound in gigasampler format that I like.
While I was going after this problem I went to the store and played another XV-88 just for grins. The store environment was too noisy to tell if the noise existed there, too. But I also had a nearly orgasmic experience with the Korg Oasis keyboard... it runs Linux internally - sweet - it has a wonderful touchscreen interface - it sounds pretty darn good - it has ADAT outputs - it costs more than my last car did...
Bought a new 8' grounding rod for the building I'm in. Jammed it 3 feet in the ground before it stopped with no amount of hammering to budge it further. How on earth do people get these things 8 feet into the ground?