When testing the computer for my “Kosmoskatten” (“Cosmic Cat”) project I was hit by another noise infection. The groundloop was overwhelmingly infecting the output of the SB Live card.
The Kosmoskatten-computer along with my studio computer is connected to one electrical outlet (and so is a lot of other stuff in the lounge like routers and TVs etc) and my mixer and gear along with the computer screens to another.
The studio computer and the Kosmoskatten computer is connected via MIDI. And if I remove this midi connection the noise disappears!
But if I put all computers and gear on the same outlet, well then the noise is only about half as strong but when disconnecting MIDI it increases instead. Very weird. It also seems to have something to do with the computer screens because various means to unplug those decreases the noise. But I still cannot see the connection here and the ground loop noise is far too loud.
At least I have my 16 channels of AD/DA connected through fiber so at least I can work safely with those.
Still, the annoying quest continues …
In my upcoming project, “Kosmoskattens rymdljudsmodul” freely translated as “Cosmic Cat’s Space Sound Module”, I have some soundfonts made by Ian Wilson that I just seem to be able to part with. I’ll post about it later but in short it’s a computer with a SB Live card that is controlled remotely to play these very specific soundfonts built around the EMU circuit.
One problem with these old SB Live cards is that while they do have a digital output (SPDIF), it is fixed at 48 kHz due to the construction of the chip and the poor conversion.
The RME card has no problem with that but I did research my sample libraries and it seems almost all are 44.1 kHz and 16 or 24 bit. All of the NI Battery kits I checked was.
To avoid any degrading conversions (that I may or may not know about) I want to keep my musical projects at 44.1 kHz/24 bit.
Now RME Totalmix does mix different sample rates but when listening I hear a clear degradation when project is 44.1 kHz and the SB Live outputs 48 kHz. So that is a no go.
It seems I’ll have to output an analog signal and route it back into my A/D setup for the best result.
Too bad but it’ll have to do.
So MIDIYoke is a nice MIDI port patcher made back in the olden days. You might have trouble installing it on Windows 7. This is due to the new security features in Windows 7, the so called UAC.
So what you need to do is turn off UAC when installing MIDI Yoke. It goes something like this:
Go to the Control Panel -> System and Security -> Action Center -> and to the left you find the settings for the User Account Control. Set it to minimum and reboot. Install MIDI Yoke. Reboot again and reset the UAC to whatever tickles your fancy. It might be a good idea to have an administrator account while doing this.
So I’ve just the last night been looking for the cause of annoying noise in the audio cables. After a few hours it seems that disconnecting one of the USB hubs did the trick.
A lot of my gear can be controlled by the computer via USB connection so I need to find a solution for this.
I need to narrow it down.
This will be continued …
Always, *beep* ALWAYS, check internal data and power cables when there are strange problems with the computer!
(jeez, I’ve done this too many times to forget it again ….)
The world of acoustics and psychoacoustics is quite amazing.
How you percieve audio, music, sounds is very much tied in with your surroundings (speaker placement, shape of the room, listening position) but also with your expections.
Sometimes that’s a hard one for people to realize and perhaps even more so if you just spent 500€ on a 1,2m cable and “clearly heard a difference”. Well who wouldn’t?
But in this BBC documentary you can actually see and hear one of these expectations in action. It’s called the McGurk-effect.
Check it out while you can!
The McGurk-effect on YouTube
In the studio there’s two VGA cables running about 7,5 meters from the computer to the displays. They run from the graphics card with a DVI-to-VGA adapter in one end to the VGA-connection on two flat 22″ widescreens at the other end. Previously, with 1,5 m cables, there were no problems using full resolution, 1680×1050. But with the introduction of longer cables there were so I thought I’d share my experience.
The longer the cables the less resolution you will be able to achieve (and slower refresh rate as well).
Signal seems to degrade fast even with good cables. The displays didn’t get recognized at full resolution even though I tried to force it. It just wouldn’t work and I had to settle with less for the time being. I think I managed 1440×900 but otherwise only lower resolutions not really suited for these displays were available.
Graphics card and computer setup can make a difference! A couple of months later I upgraded the whole computer and with that a new graphics card.
I had to force the resolution by deactivating automatic detection (in the Catalyst driver software) but it finally solved the issue. Now I once again, happily, run at full resolution on my dual screen setup.
All in all, longer cables is a longshot for good display resolution. The only way to really know is to test the setup.
I’m just glad it finally worked out for me.