microphone inputs to .wav file on microSD card?

There's a microphone out there that sports a built-in SD memory card slot. It has a pass-through (I think), so that it can also act just like a normal musician-type microphone. Pricey though. Like: ~ $1,000 US.

I've often thought a low-cost version would be practical. Going wav instead of MP3 should save on hardware costs, and I think folks can live with wav. (?) And with SD Memory card prices so low, the fatness of wav files shouldn't matter all that much anymore...

Sure my Nokia cellphone does that. To Micro SD card.

On a sunny day (Wed, 4 Nov 2009 15:58:53 -0800 (PST)) it happened Jan Panteltje wrote in :

Actually it is .amr format, a highly compressed format.

By the way, If anyone's looking for a podcast recorder along the lines of what the OP is looking for,

We use one at our Church. For $125, you can't go wrong. We record direct to MP3 at 44.1 kHz. Sounds great.

I went looking for the other mic I was thinking about, but didn't see it on a quick Google search. Lots of "Karaoke" type mics. I want to say the one I was thinking about was either Panasonic, Shure or maybe Sampson. A big name, anyway. One you'd recognize. I know I tucked it away somewhere (probably my overgrown "favorites" list). If you need it, let me know and I'll dig up the link.

-mpm

Or a Zoom recorder. The professional digital recorders use compact flash rather than SD.

I can tell you right now the microphone inputs on the Zoom H2 are noisy. The built in microphones are fine as is the line input. You might want to check out the H4.

I see Marantz has one model that takes SD

You really want to make sure these take SDHC. I know the zooms have a

Thanks to all who replied.

I was really hoping to put together a system based on something like the dsPIC and an audio codec with an SD or uSD card for storage.

Dave

Or a Zoom recorder. The professional digital recorders use compact flash rather than SD.

I can tell you right now the microphone inputs on the Zoom H2 are noisy. The built in microphones are fine as is the line input. You might want to check out the H4.

I see Marantz has one model that takes SD

You really want to make sure these take SDHC. I know the zooms have a

No, its a limitation of FAT32.

Opps, Its FAT16

don

The Aus magazine "Silicon Chip" did one within a few months. Google and you can buy the article on-line.

On a sunny day (Thu, 05 Nov 2009 07:05:32 -0700) it happened don wrote in :

Actually 2^32 is > 4.289 GB. Unless MS screwed up big time, that 32 bit file system (hence the name FAT32) should do 4 GB.

The problem with SD and SHDC cards is because of the changed sector sizes (512 byte versus 1024 bytes), and some old hardware or firmware not being able to cope with that.

In another thread, I discovered the BlackFin processors were really the way to go for something like this. At the time, I was looking at a fast 8051. (100 MHz variety)

I was (am) still convinced I could handle the data rate (16 bits @

-mpm

When you are writing relatively high bandwidth data to SD cards you end up having to have a fair bit of buffer memory IME, and most small microcontrollers don't have much internal RAM available.

Fast microcontroller like AVR is sufficient to store uncompressed audio to flash. However, pretty soon you will find out that you need a full featured file system, a connectivity (USB or Ethernet), some user interface, clock, VOX, AGC, equalizer, data compression, synchronization, etc. etc. etc. The demands grow up quickly to 100MIPS and several hundred K of code and data, which is out of the league of small microcontrollers. BlackFin or TMS55xx would be an adequate choice.

Vladimir Vassilevsky DSP and Mixed Signal Design Consultant

Thanks for that... Good insight.

I was (am still thinking about) using a dsPIC33FJ256GP506 running at 80MHz (40MIPS). This chip is supposed to have an itegrated DMA controller which might be able to improve the data transfer to holding buffers. These PICs have a fair amount of internal RAM (over 3.5KB) so I planned to set up a pair of ping-pong buffers for the microSD card interface. I can also probably get by with 22.050KHz sample rate so that might give me a little more time.

I've ordered a DSP development kit from CCS so I should be able to check out some of thesee theories soon :)

Dave

In another thread, I discovered the BlackFin processors were really the way to go for something like this. At the time, I was looking at a fast 8051. (100 MHz variety)

I was (am) still convinced I could handle the data rate (16 bits @

-mpm