How to use laptop for sound

jsml

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I ran sound from MacBook Air’s headphone jack (to XLR into mixer) at a high school theater and it sounded awful.

What do I need between the computer and the mixer? Am I looking for an “external sound card”? “Pre-amp”? “DAC”? And if so, what specs do I need to meet to do well in a medium-sized house?

Also if I am setting up very simple set of 2 speakers for a small (community, low-tech) event, I don’t need a mixer necessarily right?
 

RonHebbard

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I ran sound from MacBook Air’s headphone jack (to XLR into mixer) at a high school theater and it sounded awful.

What do I need between the computer and the mixer? Am I looking for an “external sound card”? “Pre-amp”? “DAC”? And if so, what specs do I need to meet to do well in a medium-sized house?

Also if I am setting up very simple set of 2 speakers for a small (community, low-tech) event, I don’t need a mixer necessarily right?
@jsml One caution you need to be aware of: All 3 conductor (Tip, Ring, Sleeve) headphone jacks are unbalanced stereo sources NOT TO BE CONFUSED WITH balanced sources of audio. Too many end users will connect a 3 conductor (Tip, Ring, Sleeve) male plug to an XLR-3 connector then plug the XLR directly into a balanced mono input THEN WONDER WHY THEIR BASS FREQUENCIES and vocals (normally panned down the centre) DISAPPEAR often with the ambient reverberation remaining sounding akin to the cheap 'n cheerful vocal eliminator they've unintentionally created.
I'll butt out now as I'm sure our many experts will be along shortly, if they haven't posted while I've been typing.
Toodleoo!
Ron Hebbard
 
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I run laptops and iphones straight into a mixer all the time. But I plug into a stereo channel with 1/4" inputs, not a mic input.
 
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josh88

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If you dont need it to be stereo and are fine with it just being summed to mono, my pick is an LTI block if you want stereo, I like a PC DI

but there are a lot of ways to skin a cat and protect your laptop from getting fried by phantom power.
 

RonHebbard

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I run laptops and iphones straight into a mixer all the time. But I plug into a stereo channel with 1/4" inputs, not a mic input.
@Joel - Studio 52 and @jsml If you're coming out of a 3 conductor (Tip, Ring, Sleeve) earphone jack and connecting it to a pair of 2 conductor (Tip Sleeve) 1/4" mono male plugs into either one STEREO input channel with a pair of 1/4 TS inputs
OR if you're coming out with the same connections into two mono input channels panned left and right respectively, your results should be as anticipated.
If / when you inadvertently connect as I cautioned in Post #2 you won't be pleased with your results.
I'll butt out again.
Toodleoo!
Ron Hebbard
 
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jsml

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@jsml One caution you need to be aware of: All 3 conductor (Tip, Ring, Sleeve) headphone jacks are unbalanced stereo sources NOT TO BE CONFUSED WITH balanced sources of audio. Too many end users will connect a 3 conductor (Tip, Ring, Sleeve) male plug to an XLR-3 connector then plug the XLR directly into a balanced mono input
@RonHebbard Pardon my ignorance, but, what does this mean in terms of what I should have done? Should I have a mono headphone to a stereo XLR? Would that have fixed this? Why does a single headphone to single XLR cable exist? I have yet to ever see two headphone jacks on a device.
 

RonHebbard

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@RonHebbard Pardon my ignorance, but, what does this mean in terms of what I should have done? Should I have a mono headphone to a stereo XLR? Would that have fixed this? Why does a single headphone to single XLR cable exist? I have yet to ever see two headphone jacks on a device.
@TimMc and / or @FMEng and / or
@RonHebbard Pardon my ignorance, but, what does this mean in terms of what I should have done? Should I have a mono headphone to a stereo XLR? Would that have fixed this? Why does a single headphone to single XLR cable exist? I have yet to ever see two headphone jacks on a device.
Can any of you phrase what I'm trying to say in post #2 better? And / or tell me I'm laden with excrement?
Toodleoo!
Ron Hebbard
 
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RonHebbard

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@RonHebbard Pardon my ignorance, but, what does this mean in terms of what I should have done? Should I have a mono headphone to a stereo XLR? Would that have fixed this? Why does a single headphone to single XLR cable exist? I have yet to ever see two headphone jacks on a device.
@jsml Using the single headphone jack is not a problem and I'm not suggesting you'd be any better off with a device with two headphone jacks, if you found one. I've used Control Booths's Bat Call, (Like in the old Batman comics) to summon the attention of a few of our regulars who can probably word my caution in post #2 clearer. OR they may just tell me I'm phuquin' full of excrement which could easily be the truth.
Toodleoo!
Ron Hebbard
 
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jsml

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@RonHebbard Sorry I didn’t word my reply very well. I don’t really understand balanced vs unbalanced AND what a better solution would have been when I don’t think this board had any more 1/4” inputs I could have used.

So, I guess I’m saying:

Would this item here have solved the problem? https://www.amazon.com/dp/B00YSAVW28/?tag=controlbooth-20


And I also wondered, why in the world a headphone jack to a single XLR cable even exists if all headphone jacks are unbalanced and you shouldn’t ever use such a cable???


Anyway, I have run my laptop as sound for many events without a problem when I or a friend set-up the sound (laptop straight into a mixer via a headphone to stereo 1/4” or RCA) into powered speakers that we set up, but at all of the theater houses / established venues, this was not the setup and going straight from headphone jack into a mixer did not work. One of the three required a box of some sort. Another, for some reason, the quality coming out of my thunderbolt through an HDMI cable was much better while the headphone jack’s signal was again horrible. The third, I’ve described in this post and similar to the second.


Thank you!!!
 

jkowtko

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Don't plug your laptop's headphone jack directly into XLR board input or you will risk frying your laptop's headphone circuitry if phantom power is on.

For better/stronger sound I suggest a UBS audio interface (e.g. Behringer UMC202HD) which will provide proper balance audio outs and keep your laptop isolated from the analog voltages.
 

jsml

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Don't plug your laptop's headphone jack directly into XLR board input or you will risk frying your laptop's headphone circuitry if phantom power is on.

For better/stronger sound I suggest a UBS audio interface (e.g. Behringer UMC202HD) which will provide proper balance audio outs and keep your laptop isolated from the analog voltages.
Thanks! Would this work?
Radial Engineering ProAV2 Stereo Direct Box https://www.amazon.com/dp/B001ESK5NO/?tag=controlbooth-20
 

josh88

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Thanks! Would this work?
Radial Engineering ProAV2 Stereo Direct Box https://www.amazon.com/dp/B001ESK5NO/?tag=controlbooth-20
Yes that would work.

DI is a Direct Input
LTI is just Rapco's Abbreviation for LapTop Interface
DAC is Digital Audio Converter (various kinds of interfaces between a board and a computer, usually a USB interface these days)
Preamps boost weak input signal and turns it into a stronger, usable signal.

and external sound card would be a sound card, outside of your computer, or in place of your built in sound card that allows you to have different connection options. Like I said multiple ways to skin a cat.
 

jkowtko

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Yes that would work.

DI is a Direct Input
LTI is just Rapco's Abbreviation for LapTop Interface
DAC is Digital Audio Converter (various kinds of interfaces between a board and a computer, usually a USB interface these days)
Preamps boost weak input signal and turns it into a stronger, usable signal.

and external sound card would be a sound card, outside of your computer, or in place of your built in sound card that allows you to have different connection options. Like I said multiple ways to skin a cat.
Yes that would work.
An advantage of a USB audio interface over a DI is that the USB Audio interface handles signal in both directions ... so you can record off your board's outputs, or mics, or any other pieces of equipment that have line outs, into your laptop via USB. It also can have a better quality analog-to-digital conversion processor than what is in your laptop.
 
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jsml

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An advantage of a USB audio interface over a DI is that the USB Audio interface handles signal in both directions ... so you can record off your board's outputs, or mics, or any other pieces of equipment that have line outs, into your laptop via USB. It also can have a better quality analog-to-digital conversion processor than what is in your laptop.
The one I linked to above is cool b/c it has RCA, 1/4", and XLR outputs. Do you know of a USB audio interface that is similar? And is "USB audio interface" what I search for when looking to purchase / research?

A concern I do have about a USB output is that aren't USB ports more prone to water damage, etc., than headphone jacks? Just concerned b/c I have a used MacBook and worried that I will discover a USB problem mid-show, because...you never know.
 

AudioGreg

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My favorite USB interface for this is the ARX USB 3. Excellent quality and both input and output capability. Transformer isolated in both directions as well for good sound and protection from things like phantom voltage and ground loops. About $350. https://www.markertek.com/product/a...-o-balanced-stereo-xlr-inputs-outs-usb-di-box

My second fave is for the more budget minded, the Peavey USB-P probably the only recommendation this company will ever get from me LOL. Output only, but still sounds great. Also transformer isolated. About $50. https://www.bhphotovideo.com/c/prod...TxydszmeSJqKiQaAuYSEALw_wcB&lsft=BI:514&smp=Y

Both of these units are "Class devices" and need no special drivers for Mac or windows.

I wouldn't worry about USB. I've been using this setup for about 15 years with no issue.
 

jkowtko

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The one I linked to above is cool b/c it has RCA, 1/4", and XLR outputs. Do you know of a USB audio interface that is similar? And is "USB audio interface" what I search for when looking to purchase / research?
Radial is supposedly a top brand for DI boxes, Countryman is another top brand ... but again a DI box only passes signal in one direction ... from a non-balanced source (e.g. headphone jack of a laptop or DVD player, electric guitar output, etc) to the sound board's input channels. It is also analog only (which may be fine for your purposes).

A concern I do have about a USB output is that aren't USB ports more prone to water damage, etc., than headphone jacks? Just concerned b/c I have a used MacBook and worried that I will discover a USB problem mid-show, because...you never know.
I've never had a problem with USB on my Macbook, or any of my windows laptops in the past. Also, your Macbook should have multiple USB ports, whereas it has only one headphone jack ... either way you should have backup cabling options at your fingertips just in case ...
 
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jsml

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My favorite USB interface for this is the ARX USB 3. Excellent quality and both input and output capability. Transformer isolated in both directions as well for good sound and protection from things like phantom voltage and ground loops. About $350. https://www.markertek.com/product/a...-o-balanced-stereo-xlr-inputs-outs-usb-di-box

My second fave is for the more budget minded, the Peavey USB-P probably the only recommendation this company will ever get from me LOL. Output only, but still sounds great. Also transformer isolated. About $50. https://www.bhphotovideo.com/c/product/759075-REG/Peavey_USB_P_USB_P_USB_Direct.html/?ap=y&gclid=Cj0KCQiAgMPgBRDDARIsAOh3uyJDGNMaCR83tLLHcfBkJVQxwiIki-2lsKCWBIv69TxydszmeSJqKiQaAuYSEALw_wcB&lsft=BI:514&smp=Y

Both of these units are "Class devices" and need no special drivers for Mac or windows.

I wouldn't worry about USB. I've been using this setup for about 15 years with no issue.

Thanks! I do worry too about the USB cord being an extra connection point. But if it's been working great for you for 15 years, sounds good! So the Peavey protects from phantom power?
 

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