Quote:
Originally Posted by dpeterson3
One of my teachers mentioned that the FCC is reducing the wireless bandwidth for wireless mics.
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Yes, this is correct, I would just recommend buying future-compatible mics.
Quote:
Originally Posted by dpeterson3
Each mic could have its own IP address, so everything can talk on the same network.
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The problem with using IP based networks is they weren't designed for real-time applications. You could probably get sound through them but it is probable that it would end up sounding like a poorly dubbed movie. Also, something to keep in mind is if you've ever used VoIP, you know the frequency range is not that great. You might be able to tune it like you mention so that it sounds ok for plays, but musicals would almost certainly noticeably bad. The art of sending quality musical audio over a wireless communication link is the subject of much research and in any case ends up needing a lot of bandwidth: as stated
here you realistically need a sampling/transmission frequency (the sampling frequency on A/D follows approximately the same rules as the carrier wave of a modulated radio system) of 10x that of the highest frequency you want to accurately reproduce. It's hard to get that much data running over an IP network in real time without getting packet congestion.
Quote:
Originally Posted by dpeterson3
A web GUI could be loaded on each mic so it can be tuned to the individual using it. [...] I didn't want to use serial because I wasn't sure I could have a web GUI to tune the mics.
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I assume by tuning you mean some sort of frequency equalization (EQ). In order to have this on-chip, you're really going to have to look at a microcontroller that has DSP functionality like Analog Devices Blackfin (TI also makes a good line of DSPs, I'm just not familiar enough with them). Also, a web interface means you're goingg to have to run a webserver on the device, which could probably be done on a STAMP or PIC, but in order to have that running at the same as you're piping through the audio data, you're going to have to have some type of real time scheduling. I'm not sure if FreeRTOS has a PIC or STAMP port, but that's where I'd start looking. If there isn't one, FreeRTOS is supposedly fairly easy to port.
Quote:
Originally Posted by dpeterson3
A computer in the back running some custom software could handle the mixing.
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Supposing you figure out the real-time communication, try looking at a realtime audio processing OS. If you're familiar with OS X programming, that could be a way to go, or take a look at Ubuntu Studio. I'm not sure if either of these have a real-time IP stack though, which would almost probably be necessary.
Quote:
Originally Posted by dpeterson3
Is there anyway to build those serial converters. I was looking at the sticks because I can get a chip that converts TTL to USB signals. I thought that would do the same thing as the converters you mentioned.
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The chips you're looking at probably present a USB
device interface proxy for TTL. In order to interface with a USB stick, you need a USB
host interface. (EDIT: oops sorry ErikVanWyk looks like you beat me to it).
Quote:
Originally Posted by dpeterson3
btw, that headset is pretty much what I want to do at a reduced cost. If I could do the interface with the stick, then the total cost for a mic would be around $70, which is still cheaper than most production wireless mics.
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See above comments and I think you'll be hard pressed to get it under $70. You might still be able to get it under the price of a commercial wireless mic, though, but then you have to factor in Ben Franklin's wise maxim that Time is Money.
One final note is to look at the new AVR32 chips from Atmel. The UC3 family has some DSP capability and the AVR32s have an onboard Ethernet interface that you could maybe couple with a Ethernet-Wifi bridge. There's also a
FreeRTOS port for the UC3 series already released, and it appears to include webserver code already written.
This post is not necessarily meant to discourage; I think it's a fascinating idea, you just have some development challenges to work through.
--Ryan