what the *^**&(%* is optical output?

[jbazell]

and coaxial? does anyone actual use them for home computer recording? the new korg preamp looks fun, but i don't understand either of those cables. what ever happened to usb and firewire? is there some way to convert optical or coax to usb/firewire? if so, is converting to usb or to firewire prefereable.
thanks anyone with any insight into this, and vive sweetwater!

[tech1]

Optical is a digital connection format using a fiber optic cable that allows hi-speed data transfer between two devices. Coaxial is similar, but uses a different type of cable. Both are digital formats, so audio data either must be digital to begin with, or must be converted into a digital format. The digital format in use by the new Korg Preamp (I'm assuming you meant the TP-2) is S/PDIF; this data format can be sent over either an optical or coaxial cable.

Firewire and USB are not in any way related to optical and coaxial connections. In other words, you do not plug a coaxial cable directly into a computer from an interface or preamp; rather, coaxial and optical connections are part of the interface, which "talk" to the computer over USB or Firewire (or PCI, PCI-e, etc.).

These formats are extremely common, and are in very wide use across home and professional studios. I have even seen consumer-grade stereo receivers with coaxial S/PDIF connection. One of a million uses, off the top of my head, would be to use the Korg preamp to add inputs to an MBox2. The MBox2 has 2 analog inputs and 2 coaxial S/PDIF inputs, for a total of 4. Using the preamp in question, you can add 2 analog inputs on the preamp, which get converted to S/PDIF inside the preamp, then sent via the coaxial cable to the MBox2. And just like that, you have 2 more inputs.

If these connections (optical and coaxial) are causing too much of a problem for you, I suggest either not using them or looking for a device that does not have digital connections. They are not necessary to the preamp, but provide additional flexibility for connecting to various studio setups.

I hope this helps, and if you have additional questions, please call us at (800) 222-4700.

[jbazell]

sorry, still confused. i understand that coaxial and opto out are just digital cables, but my question is, why would any new device have them instead of something computer compatible?

are you saying that the digital signal encoded in some proprietary format instead of just streamed as information in the same format as, say, firewire? if you need to plug the new korg into an mbox so you can plug it into your computer, what is the mbox doing, exactly? my understanding is that an mbox is passive, relying on cpu to ad/da. but if the mbox is just acting as a conduit between one kind of cable carrying digital signal and another, why isn't there a much cheaper adapter solution?

i guess the real question is why new devices that are streaming digital anyway would have limited connectivity even with adapters. i know this is complicated -- that firewire and usb, for example, have different abilities also -- but i haven't been able to find a good explanation of this, or how the number of tracks you record simultaneously over usb/firewire/optical/whatever is determined.

thanks again.

[tech1]

I'll try to take these as they come. A new device would limited to ADAT and S/PDIF if, say, you already had something that was cmputer compatible, such as an MBox. Pro Tools will not "see" any other audio devices besides the MBox, so to get additional inputs, you can't have a device that interfaces with the computer; you need S/PDIF.

Yes, the audio stream is different. These formats are not proprietary, though. They are used by almost all manufacturers in some way or another. In the situation you described, the MBox is acting as the interface. interfaces are named as such because they "interface" with the computer. The accept streams of digital and analog audio data and convert it into a bitstream that a computer can interpret. The MBox is actually quite active; it does the job of D/A and A/D, as well as converting to a CPU-friendly bitstream. There are cheaper solutions for audio interfaces; you basically pay for the quality of converters, number of channels, and any included software. interfaces that aren't as high in quality certainly go much cheaper than the MBox. But, with the MBox you also get Pro Tools.

New devices are limited only in what their purpose is. A preamp with only S/PDIF connections is clearly designed solely for the purpose of adding S/PDIF I/O to an existing setup. Each new device is targeted for a specific purpose. You need to figure out what you are missing first; then, find the product to fill that particular void.

A basic breakdown of bandwidth:
- S/PDIF (coaxial or optical): 2 channels, up to 96kHz sampling rate.
- ADAT (optical): 8 channels at 44.1/48k, 4 channels at 88.2/96k (also called S/MUX).
- USB: bandwidth determined by interfcae, but typical not more than 8 in and 8 out.
- Firewire: bandwidth determined by interface, up to 50+ ins and outs on some units. Recording bandwidth is also limited by computer performance; the faster your processor and hard drives, the more tracks you can run.

Does this help?