Freesound Forums

This might sound a little weird, but I need a recording of the 'ultrasonic' noise that a dog repeller makes. (and someone clever to tell me if playing it back through normal speakers will work....)
Is special recording equipment required to record / playback such a noise?

I'd like to let my neighbour's doggie know that I don't like being woken up at 1,2,3,4,5 & 6 am, and I would very much like him to stop, so I want to set up such a recording with a spare pc, and bark activated play with the speaker next to his fence....and before you ask, the neighbour won't cooperate, and the council will take 6 months to do anything about it.....by that time myself, my wife and 2 year old will have gone mad from sleep deprivation....

Any takers?

you could download a free tone generator and set it at something like 35khz and blast it from a speaker... thats what I'd do! LOL

hmm, i wouldn't know. as bpenman said, playing a high frequency would do the job i would have thought. Let us know how this turns out, i'm intrigued!

cheers for the advice, I'll try that. Hell at this point I'll try anything........

Well I tried that, but I can hear the sounds being generated.....I thought tones within that range were meant to be inaudible to us? Damn clever tone generator but......but if I blast this through speakers I'll replace the dog as the pariah of the neighborhood.....
I checked out some of the commercially available products, and they reckon 20-35KHz is the go, but what the tone generator outputs is definitely audible. I set the tone generator to run a tone from 20000Hz to 30000Hz in a sine pattern (definitely creates some discomfort for me and annoys the hell out of my wife in the next room)
Now I just need to figure out how to give the dog a burst when it pipes up. Maybe I should experiment with this during the day when all the neighbors are at work just to see if it has any effect on the dog at all.....lol...I have a headache now, I'm pretty sure I'm not part dog....

What makes you think an annoying sound will make it stop barking? The only long term solution is to get your neighbours to train their dog.

Anton
What makes you think an annoying sound will make it stop barking? The only long term solution is to get your neighbours to train their dog.

Yeah, I bet the dog will start barking *and* crying
I for one find crying more anoying than barking ! The original poster should listen to a song named 'Seamus' appearing on the Meddle album by Pink Floyd, gives an idea... (BTW, I could never stand this song due to the dog's 'performance').

saludos

domonsura
Well I tried that, but I can hear the sounds being generated.....I thought tones within that range were meant to be inaudible to us? Damn clever tone generator but......but if I blast this through speakers I'll replace the dog as the pariah of the neighborhood.....

How did you generate them, or what form are they now in? Standard WAV at 44.1 KHz (CD standard) cannot produce anything above 22 KHz (Nyquist theorem). If using WAV, you would need to use say 96 KHz sample rate for generation and playback of 35 KHz.

Mike

He rightly, you must have an Sample Rate two time higher minimum else the software will generate an harmonic frequency and this is not the exact frequency. But but moreover 96Khz sample is not enough because 96Khz / 2 = 48Khz and 38Khz is too near, i think that the result on an oscilloscope will be an modulated frequency at 38Khz. You must consider that too...

I do not think HardPCM is correct when he says you would need a greater than 96 KHz sampling rate to reproduce a 35 or 38 KHz tone.

See http://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem

I quote "Exact reconstruction of a continuous-time baseband signal from its samples is possible if the signal is bandlimited and the sampling frequency is greater than twice the signal bandwidth."

Hence I believe that anything over 76 KHz sampling rate would fully suffice.

Mike

....Ok I"m not correct, Thank to remind me the Nyquist rules :? , but it"s always strange to see that result for an frequency of 38Khz:

http://img444.imageshack.us/img444/6797/totova9.gif

So because of the Nyquist rules, for generate an Sine frequency of 38kHz you will be okay with an Sample rate of 96kHz
Sorry for the confusion....

make sure the monitors/speakers can generate sounds up to 38KHz

I'd have thought your best bet would be a standalone oscillator with pitch control, any old amp, and speakers capable of going ultrasonic.

I have no idea if this would do the job:

http://www.maplin.co.uk/module.aspx?ITAG=FAQ&ModuleNo=3199&doy=17m3#faq

I think you have 2 main problems: First, you need to reproduce 35 Khz signal from any comercial source like CD, or PC Soundcard, and this equipment is mainly designed to reproduce standard audio formats (20Hz - 20Khz) unless you have a Soundcard with 96Khz sample capability. but your second problem are your speakers, and comercially they reproduce at 16Khz or 22Khz at -3dB (It depends from manufacturer and price, of course).
But I think you have a solution:
1 - go to Radio Shack and buy Realistic Super tweeter, this can reach 50Khz
2 - use an 555 IC to build and oscillator ( in fact you can modify the center frequency with only move one potentiometer and find what frequency is more effective with the dog)
3 - attach signal out of 555 IC to a TDA2040 amplifier (100Khz Bandwidth), and the output to your tweeter.

and that is all, you have your own dog repeller.

P.S. Sorry my bad english

Why go to the trouble of actually making a high frequency sound that is inaudible to humans anyways? if this is for a video or something, then the audience wont be able to hear the sound in the first place, so wouldn't it be easier to just have no sound at all?

I have the same issue with my neighbor's dog. How did your plan work out? Please let me know what worked for you.