BrokeInBendigo

I've had my GPX 5000 for just about 1 year but I'm really into prospecting now and would like to have the best technology available for my efforts. Hopefully the next ZVT detector is closer to the 6000 in terms of ergonomics than the 7000. I'm holding off upgrading until that time I think.

I figured out how to make my GPX light as a feather the other day. Used a heavy 1.6m crowbar to dig for about an hour. GPX and my pick felt like nothing. 
 

I don’t think the GPX is too heavy unless I put a 25” coil on it. Even with a 19” it’s manageable without a bungie - and I’m not a large or very strong person. But I do use it almost daily for a few to several hours, and I’ve built up the muscles. Also I switch arms (right swings for 80% then takes a break with left for 20% of time). 
 

I suspect the main issue for people detecting for long periods of time is RSI - we can work up the muscle to swing but you can’t really do anything about RSI besides switching arms. After a day swinging a large coil I feel some non-muscular aching in my shoulder - I’ll have to be careful about that in the future. 
 

No comment on the GPZ though. Never swung one. Feels stupidly heavy, and a big coil must really screw up the weight distribution. 

1) IS GPS NECESSARY/BENEFICIAL ON A PI UNIT?

No. With all due respect to your engineers, there is no way you can make a better GPS than my garmin unit or mobile phone, without years and years of development and a very significant cost to customers. Please spend your time and money on making a great detector. Leave the gps to gps companies.

2) IS COLOR SCREEN MORE PREFERRED? ADVANTAGES / DISADVANTAGES 

Not necessary, I’d be 100% happy with black and white with a sensible UI.

3) ARE YOU OK WITH AN EXTERNAL CABLE AROUND THE SHAFT?

As many others have said, we are all hoping to be able to use our GPX coils, which means external cables. Having external cables also seems to be simpler and less prone to issues.

4) COILS - SIZES AND SHAPES (3 PLEASE)

please let us use GPX coils and then this is a non-issue. But, a small elliptical (10x5”), medium round (12”) and larger round (18”) would cover most situations.

5) IS 10 FT WATERPROOF GOOD ENOUGH? 

Absolutely. 
 

thanks NM, looking forward to your PI detector!

This guy is the real deal. Amazing series of videos on his channel, some prospecting secrets hinted at, and the process of small scale mining.

5 hours ago, 2Valen said:

Some formats do have higher audio than the video, and that is what I am referring to. Most audio in the standard MP format does require more memory than typical video. The compression rate for video on a cell phone for example is much lower than the audio compression because it is in stereo MP format. I have been doing audio for 50 years and have seen this since about 1995. Prior to that date video would eat the memory like candy and ask for more, because of the compressed bandwidth. It is not the same as it used to be.

When I add audio to a new video that I put together the video is always lower even in a high quality mode of production. Processing the video takes quit a bit of memory, but when storing the video when it is complete uses far less.

It depends on what type of video and audio that you are using and what type of equipment you are also using.

In no typical video format will the audio be a higher bitrate than the video... https://en.m.wikipedia.org/wiki/Bit_rate

MP3 maxes out at 320kbps CBR for example - this is quality that is indistinguishable from lossless for 99.999% of listeners and audio playback setups. At 320kbps you have barely-useable video. 1080p h.264 is in the mbps range for video and the audio stream will be no more than 320kbps. 

Your video quality decreases when you add audio for two reasons. Firstly you are re-encoding the video when you add audio to it. Secondly you are adding data to the media stream from the audio and if you keep the same end bitrate (as is common in video editors where you set a quality profile), that leaves less bandwidth for the video.

Metal detectors typically use only a relatively small frequency range is used for pitch (about 300 to 3000 Hz thereabouts), and the sample rate is quite low as well. With the advent of devices like arduino, teensy, etc it would be trivial to handle audio processing as described in this post. I think we’d need to talk to a designer of a modern metal detector to determine why the audio has been so similar across detectors for years. Odds are, it’s because people are conditioned to the classic metal detector sounds and if it changed substantially, productivity would decrease. In other words, this is a cultural limitation and not a technical one. 

On 8/7/2020 at 11:32 AM, 2Valen said:

When processing audio the audio takes up so much memory that you would not have enough storage room to handle that much information. When you use a phone to video anything the thing that uses the most memory is the audio not the video. The ratio is close to 10 to 1 when talking audio versus video.

That is probably the main reason it is not done, there would not be enough room for the detector to store all the information.

Huh? Audio bitrates are significantly lower than video. We have dedicated GPUs to handle video processing with their own RAM. Audio processors and DSPs have far fewer resources than video for a reason - audio is far simpler than video. Maybe I’m not understanding correctly but audio does not need more memory than video.