What is the best feedback audio tone for target info....

[moodz]

I am up to the last bit of coding on my detector and I have been so focussed on all the other bits that I did not think about the audio feedback much.
So what is best ...

A constant frequency tone that varies in amplitude.
A fixed amplitude tone that varies in frequency.
A gieger counter click-click.
A gated oscillator ...beep-beep .. or tone on/off
A two tone shift ... hi / lo or lo / hi
A high voltage probe connected to a favorite bit of your anatomy ( LOL )
Others ????

Anyone got an opinion?

[Aziz]

Hi Moodz,

I'm using three features at the same time:
1. Amplitude modulation (Amp)
2. (High) Frequency modulation (f1)
3. Low frequency modulation (f2)

Output = Amp*sin(f1)*sin(f2), where f2 << f1, f2 being like the click-click generator like from 0 Hz to 50 or 100 Hz.
So you can feed in 3 independent variables (Amp, f1, f2) to the output tone.

Cheers,
Aziz

[ivconic]

For me is gated oscillator but with wider treshold range, adjustable of course.

Surfmaster PI and Barracuda's audios are closest to what i mean to say.
Take those as start and try to extend to something that will mostly remind on mixed mode audio.
Pay indeed special attention to audio stage because huge potential is locked in it.
Usually people do not realize that audio stage is very important.
Usually people do pay most of attention on earlier stages and leave audio as least important.
That's huge mistake.
So, something called as "high resolution multi waveform" audio will possibly presents perfect choice.

[Aziz]

BTW Moodz,

some of the parameters (Amp, f1, f2) are best converted into the log dimension as the human ear can detect the faint signals better this way.

[moodz]

Thanks guys ... I will try out your suggestions and let you know how I go ....

I reckon I could patent the high voltage probe though ...

[Davor]

Something like a Taser?

[Davor]

I'm musing on a notched VCO for a single signal level representation. It'd have silence in a middle, higher pitch and level on one side and higher level and lower pitch on the other.
The other channel could be added with a significantly lower or higher centre frequency.
I have a pretty good idea how to make it. One of these days...

[Mechanic]

Thanks guys ... I will try out your suggestions and let you know how I go ....

I reckon I could patent the high voltage probe though ...

It is quite novel, probably will find them in a novelty shop one day

My preference is a tone that changes in frequency and volume. A gieger counter stile indicator would not be very good cause for a deep target that only just registers there would not be much change in the response and it would be very difficult to notice.

Cheers Mick

[Davor]

You'll find my Notched VCO at http://www.geotech1.com/forums/showthread.php?19817

[Aziz]

Ooops, audio tone output in analog manner is going to be a challenge . The suggestions I made apply to the digital synthesis of the audio tone output of course.

The non-linear transformation of the parameters could be done with ease in this case and all faint or small changes can be made causing a big change.

Go for the digital synthesis.
Aziz

[Davor]

Precisely
Remember, PWM is also a digital synthesis method, and multiplication is incredibly simple there.

[golfnut]

Most would agree the least useful is a single tone with the same intensity and duration for all alloys regardless of depth or size.



The GMP - Tone ID is very useful for the various phase responses of the alloys you resolve. eg Low growling shaaar tone for Iron, plus separate tones for alloys thru silver.


I would enjoy it if the Rx signal level modified the tone volume for depth or target size.

Im aware thes boxes are trying to pull about a 90dB span of signals in.

Reading some audio web pages a 10dB signal lift is percived as a doubling in vol, so clearly a few bands would need to overlap


eg
-10 to -30dBm Rx signal Sound +10dB

-30 to -60 Sound 0dB

-60 to anything above noise floor -10dB

Essentially using the Rx signal vector lengths to play preset vol levels - may csound a bit sterile but would give the depth impression in sound vol - also would rearrange the huge Rx span to fit the ears.

S