frequency for a nice beep sound

Thread Starter

bug13

Joined Feb 13, 2012
1,808
Hi guys

I need to generate a beep sound as a feedback for user when they pressed a button, are there some frequencies that produce a nice beep sound? I am using a piezo.

Thanks guys!
 

KL7AJ

Joined Nov 4, 2008
2,225
Hi guys

I need to generate a beep sound as a feedback for user when they pressed a button, are there some frequencies that produce a nice beep sound? I am using a piezo.

Thanks guys!
400-700 Hz seems to be nice. If you want a little more bite, you can use a sawtooth wave instead of a sine wave.
 

GopherT

Joined Nov 23, 2012
8,012
400-700 Hz seems to be nice. If you want a little more bite, you can use a sawtooth wave instead of a sine wave.
A sine wave is like a ringing bell and it can be annoying. A triangle wave is more pleasant and less piercing. A square wave sounds more like a saxophone. 440Hz is a middle C and pleasant as well. Higher frequency will make it more attention grabbing (up to 3k Hz).
 

atferrari

Joined Jan 6, 2004
3,774
My (very limited) experience says that what matters for being reasonably pleasant is shape -ASDR- harmonic content and then fundamental frequency, all this managed to a discrete volume.
 

GopherT

Joined Nov 23, 2012
8,012
Just a small correction. But I agree middle C is pleasant. 440Hz was(is?) the tone on your landline phone before you make a call and is an A on the 4th octave on a piano.
https://en.wikipedia.org/wiki/A440_(pitch_standard)
Good, I knew there was something special about 440Hz, (pitch standard), I just didn't remember which note it was and I didn't have the motiviation to look. Thank you for being both musically interested and technically astute enough to make the correction.
 

Sinus23

Joined Sep 7, 2013
245
No problem your post actually made me think for a split second that I had tuned my guitar in the wrong key all my teenage years ;)
 

d0ughb0y

Joined Aug 18, 2015
5
you are probably using a passive buzzer. I suggest that you use an active buzzer (search ebay for active buzzer), so all you need to do is set the pin high to turn it on, and low to turn it off. I use this in my project and I have coded some routines to make different number of beeps and beep length to signify success, error, etc. I use timer interrupts on arduino and IntervalTimer on teensy (arm MK20 mcu) so it does not affect main program loop execution. Early on I mistakenly purchased the passive buzzer and I had code to output the square wave to generate the beep. I can tell you that you can never make the sound as crisp as one from an active buzzer.
 
Piezos have a resonant frequency. I usually drive them at their resonant frequency with a square wave if I want to get any significant volume level. Off resonance they're a lot fainter.

I also drive them push-pull with two MCU outputs if I really want more volume.

Whether I use one or two MCU outputs I always drive both sides to ground when I'm done playing a sound to relieve stress on the piezo element.

I've never tried driving piezos with a DAC output, but in my significant experience with using gadgets, annunciators (beeps) that I've heard sound a whole lot better with an exponential (bell-like) decay in the volume.
 

AnalogKid

Joined Aug 1, 2013
8,304
Just a small correction. But I agree middle C is pleasant. 440Hz was(is?) the tone on your landline phone before you make a call and is an A on the 4th octave on a piano.
https://en.wikipedia.org/wiki/A440_(pitch_standard)
Just a small correction, US and British dial tones are a combination of 440 Hz and 350 Hz.

Also, back in the days of *real* videotape, the reference level audio tone recorded at the start of every recording was 400 Hz at zero level (+8dBm). Occasionally we came across something with 1 kHz, and even more rare was 800 Hz. Those frequencies were closer to the center of the audio bandwidth, but 400 Hz was far more pleasant.

ak
 
Top