Digital Versus Analog

[MXT SNIPER]

Is it my imagination or are a lot of the newest detectors on the market missing something in the audio? The newer machines seem to be loosing their audio nuances and color. I know this happened in the guitar music world back when digital synthesizers came on the market you could replace a pile of sound pedals with just the one digital sound unit and switch back and forth between a lot of sounds, however the musicians soon discovered that their music sound was different it had lost color and nuances that only the old analog guitar sound pedals would provide, so the old pedals became very desirable in the used market place after that, but there is only so many of the old ones still working out and about. Now there is a huge market in the music world selling new analog sound pedals. Same with guitar amplifiers, there is a huge market for modern tube amplifier that deliver that old time sound the new units cannot match. I think this relates well to the detector industry.

It would seem to me that it would be highly desirable to build analog audio into detectors which are software driven. Just ask any CZ3D user what he listens for on the machine to get those deep silvers. I have been seeing more and more new detectors that have less than desirable audio id in them. Audio id is much more reliable than the vdi numbers which can as we know be different at any time on same targets depending on a lot of factors, depth, mineralization etc.

[Andi68]

When is a detector digital, and when is it analog?
Often it is talked about, without having any idea

[kt315]

about "modern" tech. i got VT40+ amplifier in repair with symptome 'a big noise'. i opened the housing... and my face gotta ROUND -!
i see VALVE on the board! then i took manual from net and read...

Main features
• The VT20+/VT40+/VT80+/VT120+ uses Valve Reactor technology, and
features a power amp circuit containing a 12AX7 (ECC83) dual triode valve
(“vacuum tube”) that would normally be used in a preamp. This allows the
amp to produce the true sound and feel of a bona fide all valve (tube) amp.


valve reactor? WHHAAATTT?! full IDIOTIZM!
all sound effects done by CORG chipo and amplifier D class on chipo. the valve is set JUST like the appeal to the past. blast in the past!
so if you are musician RUN SPEEDY OUT FROM THIS MODERN VALVE REACTOR TECH!

[Carl-NC]

The same could be said for tube hifi amps, vinyl records, CRTs, dial phones, and carburetors.

Detector audio is as good as you make it, whether it comes from an analog or digital source. Either could be lousy. Or good. Or great. There are things you can do in digital-land that are extremely difficult or impossible in all-analog.

It would seem to me that it would be highly desirable to build analog audio into detectors which are software driven.

Many PI detectors (e.g. TDI) use a micro to drive timing signals, but the entire RX path from coil to speaker is analog. I don't know of any modern VLF designs that take the signal all the way to the speaker in analog.

[homefire]

Yep, The quality and usefulness real Audio seems to have been lost in the bells and whistle departments in the digital world. All your offered now is a BAD PCM rendition of what could have been some really useful information. Gone are the days of the subtil little whispers saying GOLD ! Just some Raspy Tone with little to zero Depth and meaning to it. BEEP. NO BEEP. LOL But as stated, it could be a good as YOU make it.

[waltr]

Interesting but not sure if strictly 'digital' is to blame.

My PI detector uses a PIC to generate the audio tone but it emulates the VCO analog circuit that 'micksv' (unsure of his user name spelling) designed and posted.
The audio output of my detector has lots of subtle variations and is good for guessing at what the target is.

Info in my thread here:
https://www.geotech1.com/forums/show...ake-on-the-HH2

It is more likely that it is the design of the detector (hardware and Code) that has lost outputting info rich audio.

Designing Code for a good User interface (audio out included) is very hard. I do think a better job could be done.
My latest project is using a PIC32 processor to obtain additional info from the signals. The biggest struggle is what to do with the info.
I do want the audio to have more info than beep-beep.

[MXT SNIPER]

I have noticed the audio in one new very popular detector in particular I have bought and used recently and sold, to be lacking immensely in variable sounds in the audio over say my old GB2, it had quite a vocabulary to let you know more about the signal in the ground. For instance a "boing" sound signaled a hot rock every time which saves digging time, a zip zip signal was quite often small gold nuggets, you could pull off a signal with the coil from ground level and get a raspy tail to the target signal indicating possible shotshell shot. These are some things I consider very important to my machines whether nugget machine or coin/jewelry, most these new machines claim to have vco audio but something vital in the audio seems to be missing. I have repeatedly read same from other old timers holding on to older high performance machines as a CZ3D since it had nuances and color that gave them much better id of coins than what we are getting with a lot of the newer machines.

[waltr]

Would like to see a schematic of your old GB2 to get an idea of how the audio is generated.
Do you have a link to the schematic?

Do agree that the variations in audio you describe is a good thing.

[moodz]

http://hamradio.tomsk.ru/download/Pr...20Elseiver.pdf

see page 485

[waltr]

Thanks Moodz. Interesting book on PIC32 with some good examples.

I will study that chapter since I do want to try better audio.

[dbanner]

about "modern" tech. i got VT40+ amplifier in repair with symptome 'a big noise'. i opened the housing... and my face gotta ROUND -!
i see VALVE on the board! then i took manual from net and read...

Main features
• The VT20+/VT40+/VT80+/VT120+ uses Valve Reactor technology, and
features a power amp circuit containing a 12AX7 (ECC83) dual triode valve
(“vacuum tube”) that would normally be used in a preamp. This allows the
amp to produce the true sound and feel of a bona fide all valve (tube) amp.


valve reactor? WHHAAATTT?! full IDIOTIZM!
all sound effects done by CORG chipo and amplifier D class on chipo. the valve is set JUST like the appeal to the past. blast in the past!
so if you are musician RUN SPEEDY OUT FROM THIS MODERN VALVE REACTOR TECH!

Yup, it is the clipping characteristics of the 12AX7 tube when overdriven, that gives tubes the sweet harmonic distortion musicians dribble over. Any tube for that matter. But in guitar amplifier, overdriven preamp tubes produce sweet harmonic sounds and feedback. Think Jimi Hendrix and Jimmy page with their M as rshal amplifiers. What you show is toy.

[dbanner]

QUOTE=kt315;254384]about "modern" tech. i got VT40+ amplifier in repair with symptome 'a big noise'. i opened the housing... and my face gotta ROUND -!
i see VALVE on the board! then i took manual from net and read...

Main features
• The VT20+/VT40+/VT80+/VT120+ uses Valve Reactor technology, and
features a power amp circuit containing a 12AX7 (ECC83) dual triode valve
(“vacuum tube”) that would normally be used in a preamp. This allows the
amp to produce the true sound and feel of a bona fide all valve (tube) amp.


valve reactor? WHHAAATTT?! full IDIOTIZM!
all sound effects done by CORG chipo and amplifier D class on chipo. the valve is set JUST like the appeal to the past. blast in the past!
so if you are musician RUN SPEEDY OUT FROM THIS MODERN VALVE REACTOR TECH!
[/QUOTE]

Yup, it is the clipping characteristics of the 12AX7 tube when overdriven, that gives tubes the sweet harmonic distortion musicians dribble over. Any tube for that matter. But in guitar amplifier, overdriven preamp tubes produce sweet harmonic sounds and feedback. Think Jimi Hendrix and Jimmy page with their M as rshal amplifiers. What you show is toy.

[MXT SNIPER]

My MXT Pro has a similar audio system in its Gold Prospecting mode, giving more audio discrimination to the user than just a beep signal. The MXT engineering report talks about this audio and its perks. Carl I find it interesting that digital detector technology allows much leeway in how well the audio portion of a detector can be built. I hope that is put to use in future dedicated nugget and Coin/jewelry machines. Loosing those audio nuances is drastic for us old timers that are used to them. I am in between vlf nugget machines right now, trying to decide on a new model. I got tired of manually ground balancing my old GB2 every few feet in alkali soils of Nevada. Gets old after a couple hrs.

[bklein]

A meaningful percentage of detectorists have hearing issues. About time the detector design takes that into account and adds features like EQ, signal expansion/compression, etc.
For you ST Micro coders take a look at Audio Weaver. It gives you audio development by using interconnected modules. Free version for ST but available for others too. Looks fun but I?m not a coder and my laptop was too old to run it well.

[MXT SNIPER]

I am using an audio enhancement device on my gpx4500 and I can say nothing but good things about it, I believe its main forte is audio compression to make the signal pop more, and it has some eq filtering as well as signal amplifier. Using the factory amp built in the batt you hear lot of background electrical noise, but using the audio enhancement device I get clean background. The Gpx does have a lot of audio features you can set internally, but it lacks a compression feature. AS far as nuances I find that a pi has little to none. But the VLF machines can really talk to you with their audio if well built. Audio ID is a much more reliable thing than vdi, screen etc.