Introduction to Multitrack Computer Interface Recording

[digidoon]

1) Balanced inputs use three wires (usually the XLR inputs are balanced) which reduces interference especially over long distances (like 20+ feet) - From my understanding you have to have 3 wires for balance (like XLR 3 prong)-
two wires send the signal in mirrored phase and then the combining of the two leaves you with a clean signal

This is correct, what happens at the Input is.. there is an electronic circuit called a Difference Amplifeier which will amplify the Difference between the two signals . Any noise / electrical interference coming from other equipment like lights ... would be found in phase on both of the signal wires , because the Difference Amp circuit only amplifies the difference between the signals on the two wires it thus filters out the Noise / Electrical interference because this is not out of phase on the two wires......

Make sense?diff.JPG

[ido1957]

Great post!

[Richard King]

Great article! Thanks for sharing this and making it easy to understand. I know that as a newbie I have really no say in this but this should really be made a sticky for the likes of me Just 2 quick questions:

2) Why do many interfaces have so many excess analogue and digital SPDIF outputs?

I use the SPDIF out of my ART Digital MPA preamp on a regular basis. It goes into the SPDIF input on my Presonus Firestudio 2626 when I need to have more than 8 channels available.

[cian]

I'm considering buying a Focusrite Saffire PRO 14. Can anyone tell me if this will record at least 4 tracks at once? It says it does 6 in the description but I'm not sure if it means 6 by Firewire. Some other ones I have seen have said they output 4 but that includes SPDIF and analogue outputs.

[digidoon]

I say Yes.. the two mic pres in front and the two Line ins in back with the white background. I have a Saffire pro40.
They also have nice routing. thats 4 inputs not including SPDIF.

[arcadeko]

bump for new members

[suzi]

You read my mind and answered my first question, even before I knew I needed to ask it! :-) Thank you SO much for this explanation!

But the picture of the cakewalk UA 1G looks like it has RCA inputs, not xlr. I'm a noob - maybe I'm missing something?

[arcadeko]

You read my mind and answered my first question, even before I knew I needed to ask it! :-) Thank you SO much for this explanation!

But the picture of the cakewalk UA 1G looks like it has RCA inputs, not xlr. I'm a noob - maybe I'm missing something?

You are correct - the Cakewalk has a 1/4" instrument (guitar) jack and RCA - no XLR and no phantom power. It is mostly for an electric guitarist IMO.

[suzi]

Cool. 1/4" I understand! Thanks!

[toleolu]

I thought your point about recording a basic guitar track twice then panning one to the left and the other to the right was really interesting. Is it better to record it twice, or just save the first track and then import it??? Just thinking about how obvious the differences will be in two seperate recordings.