which output to use for imac

flageolet

Inspired
I know there are several topics covering imac. But first, I would like to establish the best way to connect.

Which output of the ultra combined with which Imac-input would give the best results?
If there's any difference at all, in the first place.

Thx for you comments!!
 
If I can ask one additional question to that of the OP.

I have a Macbook Pro with an Apogee Duet for my I/O into the Mac. In hooking up my Ultra - should I use the two balanced outputs or the two unbalanced? And are the balanced -10 or +4 on the Ultra?

Thanks.

Barr
 
The "best" format to push to a computer is digital @ 48K sample rate. This is the highest resolution digital format available natively on the AxeFx. Since the iMac does not accept the specific format that the AxeFx outputs (S/PDIF) we need to use a converter of some type.

1) You can get a S/PDF to Optical converter and use the iMac's optical In (@ the audio-In for iMac's equipped with combination audio-in jacks) or

2) Use an audio interface with a USB (good) or FireWire (better) connection to the iMac

If you take digital out of the AxeFx into your audio interface of choice you can end with as few as one DA conversion (@ the AxeFx input) for the whole path from guitar to AxeFx to computer (guitar > ADC > AxeFx > digital converter > computer)

Alternatively you can take one of the AxeFX's audio-out (either balanced or unbalanced) into the audio interface. While technically inferior compared to digital-out from the AxeFx for digital recording, in actual usage few people can hear the difference. Despite the technical signal degradation possible, there are some very good reasons for going this route:

1) You want to send multiple copies of the AxeFx signal to different devices.
2) You want to record at some sample rate other than 48K
3) You want to record multiple tracks and/or multiple instruments at the same time.
4) Your computer does not accept the same format of digital-in as the AxeFx's digital-out.

Using the audio-outs from the AxeFx, you'll end up with three DA/AD conversions getting from the guitar to the computer (ADC > AxeFx > DAC > ADC > interface).

The decision to use the Balanced vs unbalanced audio-out from the AxeFx depends on what you are connecting to and how long of a cable run you'll have. For short runs, Balanced and Unbalanced are only distinguishable by their connectors (1/4" TS phono for unbalanced and XLR for balanced). Balanced "protects" the signal better for longer runs, in part because it offers superior RF protection. Unbalanced is cheaper, more readily available and works fine for short cable runs. In general audio signals are adversely affected by cable runs, longer runs being worse than short runs.

All of the AxeFx "audio-outs" are line-level, appropriate for sending to mixers, other line-level gear and audio interface inputs w/o pre-amp stages. If you are connecting to an audio interface located near the AxeFx then the choice of audio-outs is not important - either unbalanced or balanced will work equally well.

cheers,
 
Wow, lots of useful info right there :)

So for me it comes down to S / PFD into to Optical converter or the firewire connection.
Any remarks on the difference between those?
 
flageolet said:
Wow, lots of useful info right there :)

So for me it comes down to S / PFD into to Optical converter or the firewire connection.
Any remarks on the difference between those?

If you have use for an audio interface:
1) Are you going to record?
2) Do you need midi communications?
3) Do you need to route multiple audio inputs (beyond just the AxeFx)?

.... then the choice is a no-brainer since the audio interface will be so much more flexible and the FireWire connection can handle much more information than a single stream optical connection. Whenever you make digital-stream connections between devices (as would be the case with pushing the AxeFx signal directly into a computer), synchronizing the devices can be a major hassle. The audio interface drivers will make this process automatically. An audio interface will also handle the midi connection to the AxeFx so that you can update firmware more easily (a legit concern given Cliff's constant improvements) and use the editor from your Mac.

Since I'm a Mac guy, when I need to sort out my recording needs, I consulted a friend that works in the industry as a writer/ composer / sound designer. My friend was sold on MOTU (Mark Of The Unicorn) for interfaces and DAW (recording) software. MOTU has been a Mac-centric company for over 20 years. I've no connection to them but I do use their products and am a satisfied customer. Since I understand their product line, I'll use examples of their products to help illustrate why I think an audio interface is the way to go. There are of course other companies that make similar products, Apogee and RME / Halo stuff is consider very high quality, but often more expensive I believe.

The following will give you a good idea of the kind of things that are available. I keep a 828mk3 in the rack with my AxeFx. I think Ed Genero uses an 896mk3. Maybe he can chime in as well on that unit. Have a read through their site to get a better idea of the capabilities of the various units.

Motu Ultralite mk3 - $550 - their smallest unit
http://www.motu.com/products/motuaudio/ultralite-mk3/
http://www.motu.com/products/motuaudio/ ... fullscreen

Motu 828 mk3 - $750 - their midrange unit - more input/output choices
http://www.motu.com/products/motuaudio/828mk3/
http://www.motu.com/products/motuaudio/ ... fullscreen

Motu 896 mk3 - $1000 - their high-end unit - more preamps / XLR outputs
http://www.motu.com/products/motuaudio/896mk3/
http://www.motu.com/products/motuaudio/ ... fullscreen

Regardless of what I want to do on the AxeFx, I always hook up my laptop so I can use the editor to access the AxeFx rather than the front control panel. One fireWire connection connects me to both the AxeFx and the 828mk3 (which I use as an Audio & Midi interface and as a mixer for my stereo Ultra signal, bass guitar, two vocal mics, stereo keyboards). Using my 828mk3 as a small mixer I then send a stereo signal out to an analog mixer that collects all the other instrument inputs for the band. Someday I'll add a 896mk3 so I can handle another eight microphone inputs, but for now this set-up affords me a bunch of headroom and greatly simplifies my work.

Again, I've got no connection to MOTU. I just understand their product line and thought this might help you wrap your mind around some of the issues.

cheers,
 
what's the simplest way to get S/PDIF from the Ultra into a mac so there are no conversions?
 
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