Audio Frame Rate Above 100%

julia263

New member
Hello, Teensy Newbie here

Running Teensy 4.0 with Audio Shield Rev D2 to play one wav file off a teensy and the audio quality is very poor and noisy. I've tried running it with the sample wav files and just one audio object (including example code WavFilePlayer) but the sound is still pretty noisy. I have tried multiple SD cards and continue to get the same results. I bought a teensy 4.1 to try out a built-in SD card but continue to have the port busy issue noted by other threads and decided to revert back to the Teensy 4.0. I tried converting files to RAW format and still get very noisy sound.

I ran SdCardTest and seem to be getting audio frame rates much higher than those of other folks on the forums. Could this be a clue into what the problem is?

Results, code and soldering posted below.

Soldering.jpg



Sd Card Test Code
#include <SD.h>
#include <SPI.h>

// Use these with the Teensy Audio Shield
#define SDCARD_CS_PIN 10
#define SDCARD_MOSI_PIN 7 // Teensy 4 ignores this, uses pin 11
#define SDCARD_SCK_PIN 14 // Teensy 4 ignores this, uses pin 13

// Use these with the Teensy 3.5 & 3.6 & 4.1 SD card
//#define SDCARD_CS_PIN BUILTIN_SDCARD
//#define SDCARD_MOSI_PIN 11 // not actually used
//#define SDCARD_SCK_PIN 13 // not actually used

// Use these for the SD+Wiz820 or other adaptors
//#define SDCARD_CS_PIN 4
//#define SDCARD_MOSI_PIN 11
//#define SDCARD_SCK_PIN 13

void setup() {
Sd2Card card;
SdVolume volume;
File f1, f2, f3, f4;
char buffer[512];
boolean status;
unsigned long usec, usecMax;
elapsedMicros usecTotal, usecSingle;
int i, type;
float size;

// wait for the Arduino Serial Monitor to open
while (!Serial) ;
delay(50);

// Configure SPI
//SPI.setMOSI(SDCARD_MOSI_PIN);
//SPI.setSCK(SDCARD_SCK_PIN);

Serial.begin(9600);
Serial.println("SD Card Test");
Serial.println("------------");

// First, detect the card
status = card.init(SPI_FULL_SPEED, SDCARD_CS_PIN);
if (status) {
Serial.println("SD card is connected :)");
} else {
Serial.println("SD card is not connected or unusable :-(");
return;
}

type = card.type();
if (type == SD_CARD_TYPE_SD1 || type == SD_CARD_TYPE_SD2) {
Serial.println("Card type is SD");
} else if (type == SD_CARD_TYPE_SDHC) {
Serial.println("Card type is SDHC");
} else {
Serial.println("Card is an unknown type (maybe SDXC?)");
}

// Then look at the file system and print its capacity
status = volume.init(card);
if (!status) {
Serial.println("Unable to access the filesystem on this card. :-(");
return;
}

size = volume.blocksPerCluster() * volume.clusterCount();
size = size * (512.0 / 1e6); // convert blocks to millions of bytes
Serial.print("File system space is ");
Serial.print(size);
Serial.println(" Mbytes.");

// Now open the SD card normally
status = SD.begin(SDCARD_CS_PIN);
if (status) {
Serial.println("SD library is able to access the filesystem");
} else {
Serial.println("SD library can not access the filesystem!");
Serial.println("Please report this problem, with the make & model of your SD card.");
Serial.println(" http://forum.pjrc.com/forums/4-Suggestions-amp-Bug-Reports");
}


// Open the 4 sample files. Hopefully they're on the card
f1 = SD.open("SDTEST1.WAV");
f2 = SD.open("SDTEST2.WAV");
f3 = SD.open("SDTEST3.WAV");
f4 = SD.open("SDTEST4.WAV");

// Speed test reading a single file
if (f1) {
Serial.println();
Serial.println("Reading SDTEST1.WAV:");
if (f1.size() >= 514048) {
usecMax = 0;
usecTotal = 0;
for (i=0; i < 1000; i++) {
usecSingle = 0;
f1.read(buffer, 512);
usec = usecSingle;
if (usec > usecMax) usecMax = usec;
}
reportSpeed(1, 1000, usecTotal, usecMax);
} else {
Serial.println("SDTEST1.WAV is too small for speed testing");
}
} else {
Serial.println("Unable to find SDTEST1.WAV on this card");
return;
}

// Speed test reading two files
if (f2) {
Serial.println();
Serial.println("Reading SDTEST1.WAV & SDTEST2.WAV:");
if (f2.size() >= 514048) {
f1.seek(0);
usecMax = 0;
usecTotal = 0;
for (i=0; i < 1000; i++) {
usecSingle = 0;
f1.read(buffer, 512);
f2.read(buffer, 512);
usec = usecSingle;
if (usec > usecMax) usecMax = usec;
}
reportSpeed(2, 1000, usecTotal, usecMax);

Serial.println();
Serial.println("Reading SDTEST1.WAV & SDTEST2.WAV staggered:");
f1.seek(0);
f2.seek(0);
f1.read(buffer, 512);
usecMax = 0;
usecTotal = 0;
for (i=0; i < 1000; i++) {
usecSingle = 0;
f1.read(buffer, 512);
f2.read(buffer, 512);
usec = usecSingle;
if (usec > usecMax) usecMax = usec;
}
reportSpeed(2, 1000, usecTotal, usecMax);
} else {
Serial.println("SDTEST2.WAV is too small for speed testing");
}
} else {
Serial.println("Unable to find SDTEST2.WAV on this card");
return;
}


// Speed test reading three files
if (f3) {
Serial.println();
Serial.println("Reading SDTEST1.WAV, SDTEST2.WAV, SDTEST3.WAV:");
if (f3.size() >= 514048) {
f1.seek(0);
f2.seek(0);
usecMax = 0;
usecTotal = 0;
for (i=0; i < 1000; i++) {
usecSingle = 0;
f1.read(buffer, 512);
f2.read(buffer, 512);
f3.read(buffer, 512);
usec = usecSingle;
if (usec > usecMax) usecMax = usec;
}
reportSpeed(3, 1000, usecTotal, usecMax);

Serial.println();
Serial.println("Reading SDTEST1.WAV, SDTEST2.WAV, SDTEST3.WAV staggered:");
f1.seek(0);
f2.seek(0);
f3.seek(0);
f1.read(buffer, 512);
f1.read(buffer, 512);
f2.read(buffer, 512);
usecMax = 0;
usecTotal = 0;
for (i=0; i < 1000; i++) {
usecSingle = 0;
f1.read(buffer, 512);
f2.read(buffer, 512);
f3.read(buffer, 512);
usec = usecSingle;
if (usec > usecMax) usecMax = usec;
}
reportSpeed(3, 1000, usecTotal, usecMax);
} else {
Serial.println("SDTEST3.WAV is too small for speed testing");
}
} else {
Serial.println("Unable to find SDTEST3.WAV on this card");
return;
}


// Speed test reading four files
if (f4) {
Serial.println();
Serial.println("Reading SDTEST1.WAV, SDTEST2.WAV, SDTEST3.WAV, SDTEST4.WAV:");
if (f4.size() >= 514048) {
f1.seek(0);
f2.seek(0);
f3.seek(0);
usecMax = 0;
usecTotal = 0;
for (i=0; i < 1000; i++) {
usecSingle = 0;
f1.read(buffer, 512);
f2.read(buffer, 512);
f3.read(buffer, 512);
f4.read(buffer, 512);
usec = usecSingle;
if (usec > usecMax) usecMax = usec;
}
reportSpeed(4, 1000, usecTotal, usecMax);

Serial.println();
Serial.println("Reading SDTEST1.WAV, SDTEST2.WAV, SDTEST3.WAV, SDTEST4.WAV staggered:");
f1.seek(0);
f2.seek(0);
f3.seek(0);
f4.seek(0);
f1.read(buffer, 512);
f1.read(buffer, 512);
f1.read(buffer, 512);
f2.read(buffer, 512);
f2.read(buffer, 512);
f3.read(buffer, 512);
usecMax = 0;
usecTotal = 0;
for (i=0; i < 1000; i++) {
usecSingle = 0;
f1.read(buffer, 512);
f2.read(buffer, 512);
f3.read(buffer, 512);
f4.read(buffer, 512);
usec = usecSingle;
if (usec > usecMax) usecMax = usec;
}
reportSpeed(4, 1000, usecTotal, usecMax);
} else {
Serial.println("SDTEST4.WAV is too small for speed testing");
}
} else {
Serial.println("Unable to find SDTEST4.WAV on this card");
return;
}

}


unsigned long maximum(unsigned long a, unsigned long b,
unsigned long c, unsigned long d)
{
if (b > a) a = b;
if (c > a) a = c;
if (d > a) a = d;
return a;
}


void reportSpeed(unsigned int numFiles, unsigned long blockCount, unsigned long usecTotal, unsigned long usecMax)
{
float bytesPerSecond = (float)(blockCount * 512 * numFiles) / usecTotal;
Serial.print(" Overall speed = ");
Serial.print(bytesPerSecond);
Serial.println(" Mbyte/sec");
Serial.print(" Worst block time = ");
Serial.print((float)usecMax / 1000.0);
Serial.println(" ms");
Serial.print(" ");
Serial.print( (float)usecMax / 29.01333);
Serial.println("% of audio frame time");
}


void loop(void) {
// do nothing after the test
}


Here are my results from SdCardTest


SD Card Test
------------
SD card is connected :)
Card type is SDHC
File system space is 255802.22 Mbytes.
SD library is able to access the filesystem

Reading SDTEST1.WAV:
Overall speed = 0.86 Mbyte/sec
Worst block time = 1.35 ms
46.50% of audio frame time

Reading SDTEST1.WAV & SDTEST2.WAV:
Overall speed = 0.84 Mbyte/sec
Worst block time = 2.67 ms
92.20% of audio frame time

Reading SDTEST1.WAV & SDTEST2.WAV staggered:
Overall speed = 0.84 Mbyte/sec
Worst block time = 2.68 ms
92.23% of audio frame time

Reading SDTEST1.WAV, SDTEST2.WAV, SDTEST3.WAV:
Overall speed = 0.85 Mbyte/sec
Worst block time = 4.03 ms
138.73% of audio frame time

Reading SDTEST1.WAV, SDTEST2.WAV, SDTEST3.WAV staggered:
Overall speed = 0.85 Mbyte/sec
Worst block time = 4.02 ms
138.66% of audio frame time
 
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