Advice? simple DA out to studio monitors from Mac Pro

Discussion in 'Digital Audio' started by emillerpdx, Feb 4, 2008.

  1. emillerpdx macrumors newbie

    Joined:
    Oct 23, 2007
    #1
    hi all,

    Just wanted to ask if anyone had suggestions or recommendations for a simple and stable way to get high-quality audio out of the Mac Pro. I've got a pair of Alesis self-powered monitors (with 1/4" jacks) and using a L/R splitter on the 1/8" line out isn't satisfactory.

    I'm fine with an adapter-based solution or a breakout box, whatever's simplest and most reliable. Audio in isn't critical, though it's a nice-to-have.

    Any suggestions? Thanks in advance...
     
  2. zimv20 macrumors 601

    zimv20

    Joined:
    Jul 18, 2002
    Location:
    toronto
  3. emillerpdx thread starter macrumors newbie

    Joined:
    Oct 23, 2007
    #3
    On budget: if the consensus is that the line output will do a good job feeding the speakers with an $8 adapter, then hooray.

    But my assumption was that I was going to need to spend $100 - $200 on a Firewire-to-1/4" audio I/O breakout box.

    I'm no longer doing much audio work and want to save space, otherwise I'd route it through my old audio rack w/a mixer to handle the signal path.
     
  4. WinterMute Moderator emeritus

    WinterMute

    Joined:
    Jan 19, 2003
    Location:
    London, England
    #4
    The line out on most Macs is noisy and suffers from breakthrough noise from the processor, plus the grounding is suspect in most computers.

    There are a lot of interfaces, M-audio, Eidirol, Tascam... Decide on a budget and the features you want (firewire is better than USB, but you might want to source an interface with it's own power supply), and then go search for the best price.

    You don't mention software, I'm assuming not Protools as that comes with its own hardware.
     
  5. motulist macrumors 601

    motulist

    Joined:
    Dec 2, 2003
    #5
    You need to define what quality level you're seeking. The headphone out jack really is very acceptable for most typical audio uses. For instance, if you just want it to sound great for listening to while you compose songs at home playing softsynths output through your powered speakers, then the headphone jack will be totally sufficient. If you're outputting audio to be mixed by a professional engineer, then you need a better solution.

    I say get the cheap headphone out splitter cable, see if it works well enough for you, and only then decide if you should buy a better output.
     
  6. AviationFan macrumors 6502a

    AviationFan

    Joined:
    Jan 12, 2006
    Location:
    Cedar Rapids, IA
    #6
    The million dollar (or eight dollar, in your case) question is: what is a good job?

    Looking at some numbers, here is a portion of what Apple publishes in the Mac Pro User's Guide (early 2008 version):

    Analog audio line out (typical values)
    Based on a typical situation with playback of 1 kHz, -3dBFS 24-bit sine wave, 44.1 kHz
    - Signal-to-noise ratio: Greater than 90 dB
    - Total harmonic distortion + noise: Less than -85 dB (.01 percent)

    Analog audio out using the headphone jack (typical values)
    Based on a typical situation with playback of 1 kHz, -3dBFS 24-bit sine wave, 44.1 kHz
    - Signal-to-noise ratio: Greater than 90 dB
    - Total harmonic distortion + noise: Less than -75 dB (.02 percent)

    Note that with a -3dBFS signal, if the S/N ratio is >90dB, that equates to a dynamic range of 93dB (since they were not playing the loudest possible signal).

    For comparison, here are some numbers for the line-outs of my Echo AudioFire8 audio interface:

    Echo AudioFire8:
    - Frequency Response: 10Hz-20kHz, ±0.1dB
    - Dynamic Range: 114dB A-weighted
    - THD+n: <0.002% A-weighted

    Quite a bit better. For monitoring/mixing purposes, it especially worries me that the Apple manual does not disclose the frequency response.

    My message is this: define first what your objective is. If it's just to make music sound good, then try the eight dollar adapter and see if you are satisfied. If the objective is to create an accurate reproduction of sound for the purpose of mixing, then you should first quanitify the performance you need from the audio interface. If you have trouble quantifying the performance you need, then consult with people that do things similar to what you intend to do.

    - Martin
     
  7. emillerpdx thread starter macrumors newbie

    Joined:
    Oct 23, 2007
    #7
    Thanks for everyone's help.

    So I probably could get away with replacing the (defective?) splitter cable + adapter setup I'm using now; maybe I've got it set up incorrectly but I'm only getting mono off of it right now. I'm leaning towards an Echo AudioFire2 or AudioFire4. I had an Echo Gina 24 in my old PC and I was always happy with that, and the additional I/O of the AudioFire2 would be handy if I ended up doing more audio work again.
     
  8. Consultant macrumors G5

    Consultant

    Joined:
    Jun 27, 2007
    #8
    I fixed it for you. It applies to most PCs, not so much to macs.

    I've seen many DJs with Macs use line output and it does not have any noise issues (although I use an external sound card when I DJ).

    I've never had a ground loop issue with any mac since a old 604e clone.

    Keep in mind most macs have Optical outputs and that produces digital signal pass through.

    A damaged, loose port might be noisy, but that's platform independent. Also, if the user set the computer's output volume to low, then when it's amplified, it will be noisy.
     
  9. WinterMute Moderator emeritus

    WinterMute

    Joined:
    Jan 19, 2003
    Location:
    London, England
    #9
    Well, in my experience the line out on EVERY Mac is noisy and prone to interference from processor noise and ground issues, regardless of the model....!

    Using the optical digital output from that socket is a different matter, thats pretty good.

    The line out from a Mac is perfectly acceptable to most people for listening to a few grotty 128K MP3's, but not for pro audio applications in studio conditions.

    Yes, PC line outputs are even worse.
     
  10. Tarkovsky macrumors 6502

    Tarkovsky

    Joined:
    Jan 4, 2007
    Location:
    London/Norwich
    #10
    DJs really don't care about SQ. That's not their world.
     
  11. emillerpdx thread starter macrumors newbie

    Joined:
    Oct 23, 2007
    #11
    End result

    hi all,

    I ended up getting the Echo Audio AudioFire2. Just got it plugged in earlier and running on my new machine. It's an absolute night-and-day difference compared to the line outs, absolutely worth the $200. The issue still may have been the dongle I was using to get the signal to the Alesis monitors (and not the fault of the line out) but overall I'm happy with the AudioFire2 box as a solution.

    thanks everyone.
     
  12. AviationFan macrumors 6502a

    AviationFan

    Joined:
    Jan 12, 2006
    Location:
    Cedar Rapids, IA
    #12
    Glad to hear this is working out for you, emillerpdx!

    - Martin
     

Share This Page