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by fohman
Mon Feb 05, 2018 9:01 pm
Forum: General discussion
Topic: Powered by XLR cable "Phantom Power" (+48V 14mA)?
Replies: 35
Views: 4159

Re: Powered by XLR cable "Phantom Power" (+48V 14mA)?

Heater wrote:
Mon Feb 05, 2018 6:45 pm
Ah, I see, so you want us to advise on your scheme to make money. For free?
I'll pay you to help me complete this project if you think you could do it. PM me if so...
by fohman
Mon Feb 05, 2018 8:55 pm
Forum: General discussion
Topic: Powered by XLR cable "Phantom Power" (+48V 14mA)?
Replies: 35
Views: 4159

Re: Powered by XLR cable "Phantom Power" (+48V 14mA)?

Of course you will want to use a processor that uses a lot less power than a Pi. Perhaps an STM32 F4 or some such.
Would a STM32 F4 be able to do low latency audio DSP like EQ and pitch recognition and have analog read and write? About how much power would it consume?
by fohman
Mon Feb 05, 2018 6:07 pm
Forum: General discussion
Topic: Powered by XLR cable "Phantom Power" (+48V 14mA)?
Replies: 35
Views: 4159

Re: Powered by XLR cable "Phantom Power" (+48V 14mA)?

I'm fine with dynamic mics only. The latency can be up to 5ms I suppose without being bothersome. The idea here would be to have a kind of small project box with an XLR in and XLR out, and three LEDs to indicated accurate pitch. You plug the SM58 into the box, then plug the box into the mixer, turn ...
by fohman
Mon Feb 05, 2018 9:00 am
Forum: General discussion
Topic: Powered by XLR cable "Phantom Power" (+48V 14mA)?
Replies: 35
Views: 4159

Re: Powered by XLR cable "Phantom Power" (+48V 14mA)?

What hardware would you suggest?
by fohman
Mon Feb 05, 2018 8:38 am
Forum: General discussion
Topic: Powered by XLR cable "Phantom Power" (+48V 14mA)?
Replies: 35
Views: 4159

Re: Powered by XLR cable "Phantom Power" (+48V 14mA)?

Also, let's say we got this to work... what happens when one plugs in the unit? Does everything boot up ready to go? How much time would it take? In the event of a power loss or a disconnected power cable, how much time is there between reacquisition of power and system functionality?
by fohman
Mon Feb 05, 2018 8:34 am
Forum: General discussion
Topic: Powered by XLR cable "Phantom Power" (+48V 14mA)?
Replies: 35
Views: 4159

Re: Powered by XLR cable "Phantom Power" (+48V 14mA)?

The idea behind powering this unit via Phantom Power (from the Yamaha Rio32 I/O device) is to simplify the mechanism for possible mass production. Sound engineers know how to plug in an XLR cable and turn on the Phantom Power, and if it's that simple, I've got a marketable product. Having additional...
by fohman
Mon Feb 05, 2018 7:28 am
Forum: General discussion
Topic: Best analog read workaround?
Replies: 1
Views: 307

Best analog read workaround?

I want to get the microphone signal from a SHURE SM58 into the Pi Zero. What is the simplest and cheapest way to do this? I need the method to add as little power consumption as possible, as I'm trying to run the entire project on "Phantom Power" from the audio mixer. It also needs to be as low late...
by fohman
Mon Feb 05, 2018 6:50 am
Forum: General discussion
Topic: Powered by XLR cable "Phantom Power" (+48V 14mA)?
Replies: 35
Views: 4159

Re: Powered by XLR cable "Phantom Power" (+48V 14mA)?

Where do I find people I can pay to figure these things out and then build it for me?
by fohman
Mon Feb 05, 2018 5:52 am
Forum: General discussion
Topic: Powered by XLR cable "Phantom Power" (+48V 14mA)?
Replies: 35
Views: 4159

Re: Powered by XLR cable "Phantom Power" (+48V 14mA)?

So I'll need to build a power regulator that extracts the power from the XLR cable and knocks it down to 5V to power the Pi but also allows audio signal to be sent back down the line from the Pi in a balanced format? Any ideas on how to do this? Where do I find someone who can design and build such ...
by fohman
Sun Feb 04, 2018 6:58 pm
Forum: General discussion
Topic: Powered by XLR cable "Phantom Power" (+48V 14mA)?
Replies: 35
Views: 4159

Re: Powered by XLR cable "Phantom Power" (+48V 14mA)?

If you were able to perfectly convert 48v at 0.014A to 5v, you'd get 0.134A. A Pi0 would run on that. According to the FAQ the Pi Zero needs up to 0.2A during boot and up to 0.35A during stress testing. https://www.raspberrypi.org/help/faqs/#power I spoke with the Yamaha engineering team and they e...
by fohman
Sun Feb 04, 2018 6:52 pm
Forum: General discussion
Topic: Powered by XLR cable "Phantom Power" (+48V 14mA)?
Replies: 35
Views: 4159

Re: Powered by XLR cable "Phantom Power" (+48V 14mA)?

davidcoton wrote:
Sun Feb 04, 2018 9:20 am
Remember that no current Pi has a native audio input, so you will need a USB soundcard. For the Pi0 same applies for output.
I can't use the GPIO's? I'm not much of a computer person... are the GPIO's only digital, or can they do analog signals like the Arduino boards?
by fohman
Sun Feb 04, 2018 6:36 pm
Forum: General discussion
Topic: Audio Latency on Pi 0?
Replies: 0
Views: 208

Audio Latency on Pi 0?

I'm wondering what the roundtrip latency would be for a bit of audio processing on a Pi 0, say, for doing a bit of EQ, gating and compression on a microphone input, with a simple pitch recognition running on the side? This would be for a vocalist or instrumentalist to practice while using headphones...
by fohman
Sun Feb 04, 2018 7:07 am
Forum: General discussion
Topic: Powered by XLR cable "Phantom Power" (+48V 14mA)?
Replies: 35
Views: 4159

Re: Powered by XLR cable "Phantom Power" (+48V 14mA)?

Sorry, here is the equipment I am using, it is professional audio stuff, I have also provided a link to the user manual for the piece which supplies the phantom power itself... http://www.yamahaproaudio.com/global/en/products/mixers/cl/lineup.jsp On page 20 it shows some relevant information: https:...
by fohman
Sun Feb 04, 2018 3:03 am
Forum: General discussion
Topic: Powered by XLR cable "Phantom Power" (+48V 14mA)?
Replies: 35
Views: 4159

Powered by XLR cable "Phantom Power" (+48V 14mA)?

I want to run a Raspberry Pi using the "phantom power" from an audio mixer to process a microphone signal in a certain way. To the best of my knowledge, phantom power is +48V and about 14mA on most professional devices, although I haven't looked into exactly how the voltage is distributed over the t...

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