Mac Audio Out OK for Live?

[Ken P]

Contemplating a lightweight rig for live and in one scenario I only need 2ch stereo output - any downsides to using my MacBook Pro audio out?

It's a 2018 i7, 16GB RAM. When I connect a cable to the headphone out it says its 32bit and I can select up to 96kHz sample rate. I was thinking about a modest portable audio interface but is it really necessary for 2ch work? I could take the audio out of the Mac, into a stereo DI box which should do what needs to be done for the PA ...? Any thoughts folks?

[ben howes]

I'm sure the sound quality is fine. But do you trust the 3.5mm socket? Can you be sure that 48v phantom power won't inadvertently be applied to your computer from the desk? A DI box deals with the latter but you need a dual box. I found an audio interface was cheaper and negates the mini Jack as well.

[pk.roberts]

I've found that Macs in particular hum/buzz/motorboat when you connect the headphone output to almost anything other than a pair of headphones, so at the very least grab yourself something like this;
https://cpc.farnell.com/pulse/pls00548/ ... 0isolators

[Ken P]

Good advice, thanks. I thought of a few more reasons not to on a long drive last night:

- No headphone monitoring option.
- Level control is via software only, not a nice 'obvious' knob.
- If one USB connection on the MBP fails, for whatever reason, there are three others.

Talked myself out of that barmy idea.

[Luke W]

Good advice, thanks. I thought of a few more reasons not to on a long drive last night:

- No headphone monitoring option.
- Level control is via software only, not a nice 'obvious' knob.
- If one USB connection on the MBP fails, for whatever reason, there are three others.

Talked myself out of that barmy idea.

If you're not at the desk end yourself (assuming this is a performance rig?) then I'd be thinking along the same lines as well.

My main concern with using the built in output is the mechanical stability, as mentioned by Ben. I've done it for lots of shows with laptops but they've always been tucked safely away from anyone (including myself!) and the console has provided the level/headphone facilities you mention. I do prefer using an interface with some more solid connectors wherever possible and if it was going to live down at the stage end of the room I'd be even more keen.

[BigRedX]

As someone who has done this in the past and currently runs a similar set-up but in a more "professional" format, the headphone socket is no worse mechanically then any other consumer grade computer connector, which includes USB, Thunderbolt and RJ45. IMO none of these have any business being used in a gigging environment, but unfortunately it's all we have.

The biggest problem you will encounter (as has already been mentioned) is grounding issues, although some bus-powered interfaces are not immune to these either. On the advice from people on this forum I invested in an ART DTI box which sorted all the grounding problems out for me as well as protecting my equipment from inadvertent phantom power.

I got around the problem of having to use computer connectors on a gigging rig by building the laptop into a flight case and making sure that none of the cabling is capable of moving once connected.

I have a 3U rack with a removable top. The laptop sits on a shelf in the top 1U sounded by flight case foam and held down using the velcro stripes designed for fixing effects pedals to a pedal board. The power and USB connectors a cable tied into place so once connected there is no movement possible.

Beneath the laptop is a rack-mounting 1U interface. Feature-wise it's overkill for what we need (2 x stereo feeds for the PA and a mono feed for the drummer's click track), but the fact that it is properly rack mountable means that it can't move about in transit (unlike our previous 1/2 rack interface which could never be reliably held in place).

In the bottom 1U is a patch panel that holds all the XLR connectors that allow the set up to communicate with the other gear. This on the front of the rack which looks slightly more messy but is far easier to get to on cramped stages where the rack may often need to be placed right up agains a wall or other equipment.

Behind this panel sit all the PSUs and DTI boxes which are bolted/cable-tied/hot glued into place so no movement is possible. All the power and signal cables are run so they avoid each other as much as possible in such a small space.

This set up has worked completely reliably without any need for attention for a good number of years now. We did our first gig in almost 2 years last weekend (Leeds O2, so fairly big profile) and it performed perfectly as usual.

Hope that this helps.

[Ken P]

BigRedX, that's a really interesting and detailed insight into your live rig. Thanks.

[Luke W]

I got around the problem of having to use computer connectors on a gigging rig by building the laptop into a flight case and making sure that none of the cabling is capable of moving once connected.

I have a 3U rack with a removable top. The laptop sits on a shelf in the top 1U sounded by flight case foam and held down using the velcro stripes designed for fixing effects pedals to a pedal board. The power and USB connectors a cable tied into place so once connected there is no movement possible.

Another vote for this approach

Adhesive cable tie bases are pretty much what's holding my life together.