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1 hour ago, Reg Wilson said:

 It's a 'different strokes for different folks' scenario, and I've had situations where I have picked up a mates detector to have a listen to an uncertain signal he has picked up, only to think, "my God how can he run a machine like that?" Threshold way up, with the machine 'screaming its tits off',  the pitch so high its deafening, and running a booster as well. The perfect way to go deaf.

Same here especially the "screaming tits off" . No doubt all methods of use of MDs is personal and individual, although I have noticed over the years and I stress this is a personal observation, successful long term prospectors I have prospected with go for a steady low threshold but I`ve only prospected with a few plus they are a wee sun touched...…...?

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11 hours ago, phrunt said:

I think I've my threshold set way too high too judging by what Reg said as I have quite a loud threshold.

A high threshold and a loud threshold are 2 different things although you may not have meant what I am reading into it.

Most take their threshold down to a point of where it can't be heard and then raise it up a notch at a time until it is a nice steady hum.  On the GPZ this means starting at about 23 and usually ending up about 27 (which is also the factory default from memory).  It means a 6' 6" person is standing in 6' of water.  Their head is just out and they can hum.

If you set your threshold much HIGHER then you are likely to miss small targets as they can't breach through the higher level.  It is the same 6' 6" person but now you've put them in 7' of water - they just can't get high enough for you to hear them  - even if they stand on their toes.  If you are lucky enough to get a big target that is fine because the person then jumps like a madman and gets his head above water. 

Once you have your water (threshold) set at the right height you can use your booster to take that steady threshold as LOUD as you like - make them whisper, make them talk, make them yell.  A lot of that depends on your surrounds.  Noisy water, noisy leaf litter, busy road, quiet expanse of the outback. 

And, of course, you can use the detector to change the pitch of the 'voice' to suit your hearing.  I know most old people I see at work can understand me because I have a low pitch voice - and I talk slow because I'm a dopey ruckman  ?

I hope that analogy makes sense and I hope I'm not telling 'Grandma how to suck eggs'. 

Also happy for someone to poke holes in my analogy if it is a bit off the mark. 

As you have an SPo1 Phrunt, it would also be interesting to hear from SteelPhase where the settings other than volume come into play in that analogy - if they do at all? 

NE. 

 

 

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I wasn't going to make any comment on this post out of respect to JP as it was his post but someone asked so here's my take.

I totally agree with Northeast and his analogy. I look at it like waves on the ocean moving a small boat - just as the threshold is a carrier of the target signal. Too little threshold and the target wont be carried/moved efficiently. Too much and its swamped.

As for boosters/enhancers - I've always maintained that faint targets transmitted electrically via audio to the headphones/speaker, may not have enough electrical energy to change the way the coil in the speaker/headphones is being driven i.e. to change the sound from the threshold tone. All speakers and headphones need a certain amount of voltage/current to physically move the coil to produce sound. Same way you need an amplifier on a microphone. The microphone is putting out and electrical signal. Its just too small to drive speakers/headphones. This is why you use a booster/enhancer. And as JP said - the GPX battery amplifier and WM12 module amps are way to coarse and rough.

Now the difference with a booster/enhancer - a booster will just amplify the signal as a whole, threshold included. An enhancer will perform some form of manipulation of the signal. Yes it can only work with what comes out of the detector, but ask any audio engineer - lots of techniques are available to manipulate an audio signal. There is no need to 'colour' the audio - this implies addition of unwanted noise. The main idea is to try and make target signals louder in respect to the threshold so that faint deep targets (as well as the smaller shallower ones) stand out over the threshold tone. The threshold/target signal ratio is the all important one. I've managed to work out a technique to achieve this, and while its not perfect, I feel it works quite well. 

While the designers of modern detectors certainly know what they are doing with regards to detector design and engineering, and after examining quite a few of the audio designs in the current range of detectors, I can safely say that the audio side of things does not seem to be a big priority in their design.

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42 minutes ago, phrunt said:

Thanks for joining in on the conversation, I was hoping you would.  Is the enhancer doing a job a bit like a graphic equalizer where you can adjust what you do and don't want to hear in it's design?  Obviously a lot more complex than that but just to get an idea how it's working.

 

Not really. An EQ just either amplifies or cuts a set of frequencies. My idea is to basically squeeze a broad faint signal from the sides making it more pronounced and having more of an edge. More of a compression style of circuit rather than EQ.

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3 hours ago, SteelPhase said:

I can safely say that the audio side of things does not seem to be a big priority in their design.

Isn’t it funny that this does seem to be the case when (from memory) Reg has said on this forum about Bruce Candy’s real passion being all things sound and audio. I would have thought Minelab audio should be at the cutting edge?  

 

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31 minutes ago, Northeast said:

Isn’t it funny that this does seem to be the case when (from memory) Reg has said on this forum about Bruce Candy’s real passion being all things sound and audio. I would have thought Minelab audio should be at the cutting edge?  

 

The audio design isn't bad. It just not as good as I think it can be. 

I dare say that Minelab probably have several engineers working on the project with each assigned a particular area. Plus the focus is probably on the detection side of things as well as cost vs overall advantage.

Like with the auto industry, there are plenty of add ons that manufacturers don't have on their vehicles that can, and do, increase performance and usability.

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23 hours ago, SteelPhase said:

I wasn't going to make any comment on this post out of respect to JP as it was his post but someone asked so here's my take.............

As for boosters/enhancers - I've always maintained that faint targets transmitted electrically via audio to the headphones/speaker, may not have enough electrical energy to change the way the coil in the speaker/headphones is being driven..........This is why you use a booster/enhancer. And as JP said - the GPX battery amplifier and WM12 module amps are way to coarse and rough.

Now the difference with a booster/enhancer - a booster will just amplify the signal as a whole, threshold included. An enhancer will perform some form of manipulation of the signal. Yes it can only work with what comes out of the detector, but ask any audio engineer - lots of techniques are available to manipulate an audio signal. There is no need to 'colour' the audio - this implies addition of unwanted noise......... 

While the designers of modern detectors certainly know what they are doing with regards to detector design and engineering, and after examining quite a few of the audio designs in the current range of detectors, I can safely say that the audio side of things does not seem to be a big priority in their design.

Lots of misinterpretation in this post Steelphase and most of it is aimed at continuing the marketing ‘story’ behind the sales pitch that now seems to be taken as ‘fact’ because its been said so often.

The GPX machines have filtering in them that condition the audio, its called Boost, Quiet, Normal, Deep, these are audio profiles designed by Minelab to make the audio sound different and perhaps improve personal preference and performance, you will note it is not included in the GPZ. These audio profiles are generated from the raw signal of the detector before being delivered, so could be considered first pass not conditioning after the fact.

A ‘booster’ is required to amplify the audio because the audio out of a headphone jack just does not have enough grunt to power speakers, any amplifier can do that. Not all amplifiers do this well though, especially when the audio needs to driven louder in noisier environments.

The audio out of the detector is provided as a whole unit with everything mixed in, I’ve spent enough time in video editing environments to know what a hassle it is to try and remove certain frequencies without the audio ending up sounding awful because of poor original audio recording. You have to look at the audio supplied from the detector as being ‘whole’, because once the detector has formed and delivered that audio there is very little you can do to change the underlying fundamentals.

Filtering can remove or change certain frequencies which will change the overall way the audio sounds but you will always be affecting the whole audio supplied from the detector thereby negating the way the audio was originally delivered in its pure form. (I’m not saying this is a bad thing, just pointing out the restriction of trying to manipulate a delivered audio that has warts and all, and also the risk associated with changing something which will always has a flow on effect both negative and positive).

My complaint of the Minelab audio is to do with the volume controls and how they affect the way the audio sounds, in the case of the GPZ the threshold sweetspot is 27 unless you use too much Audio Smoothing and Volume settings (Volume = Target Volume). Using the detectors volume controls are my main complaint because they are too steppy and coarse. For MAX performance, something that takes priority in everything I do, I always use the GPZ with the Audio Smoothing on OFF (Audio Smoothing = Stabilizer on GPX), this is the point where the noise floor of the detector is at its lowest point, where you get the MAX amount of target information with zero FILTERING, in essence RAW information with no colouring. If you introduce Audio Smoothing you then tell the detector you do not want to hear any audio below the filtering point, this audio can then not be recovered because it never made the cut to be included into the audio train in the first place, no amount of volume or audio conditioning will bring it back.

What I am often seeing with people using Enhancers is they tend to introduce Audio Smoothing to soften or quieten the audio to make it sound more pleasing, because of this they then introduce even more Target Volume because they can’t hear the audio because of the muffling caused by the Audio Smoothing, this in effect causes a cascading of detector behaviour ending up with only shallow targets being prominent because when the coil passes over them they crash into peak signal almost instantly, in essence the GPZ is now just a souped up SDC. 

The audio provided by the Minelab machines is perfectly fine, it is designed well and sounds great, if however you go to town using the target Volume then things start to deteriorate. The key is to start from a stable point and then introduce volume, I prefer to do this via the B&Z but any decent booster that can deliver good amplification without distortion will do the job. The Target Volume control however has a tendency to zoom in on the threshold magnifying every little bump and jump in the threshold, operators running much past 8 on the GPX and GPZ are introducing all the minute little variations created by surface signals which then drown out the broader deeper signals. I feel every point above 8 on the Target Volume is like increasing the sensitivity by 2 points. Sensitivity above a certain point does not do much for deep targets if anything it can hide or mask them. This is extremely important if you are using the raw information provided by not using Audio Smoothing.

IMHO a booster should sound crisp and clean, it should not colour the audio provided by the detector but instead should remain true. For best performance you should only ever use the booster as a VOLUME control not a sensitivity control, with that in mind you should always set the detector to be smooth and stable and then only ever amplify that smooth stable audio as cleanly and without distortion as possible. I use the word COLOUR in reference to anything that makes the audio sound different to what is delivered by the detector. Minelab machines have plenty of ways to make the audio sound different, there is Threshold Pitch, Audio Smoothing, Target Volume & Threshold. Saying or suggesting Minelab do not prioritise audio is just plain silly, the constraint is in the many ways a person can go about using the audio because of individuality, how we hear audio is very personal and as such impossible to design for. The intent behind this post is to bring to peoples attention the need to make sure the audio settings of the detector do not end up compromising performance especially in the case of the GPZ.

JP

 

 

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4 hours ago, Jonathan Porter said:

My complaint of the Minelab audio is to do with the volume controls and how they affect the way the audio sounds

 

4 hours ago, Jonathan Porter said:

Using the detectors volume controls are my main complaint because they are too steppy and coarse.

 

4 hours ago, Jonathan Porter said:

Saying or suggesting Minelab do not prioritise audio is just plain silly

Maybe we will end up agreeing to disagree or maybe I am interpreting the word audio differently to you.

When I owned the GPZ (and absolutely loved it) and the SDC I was disappointed  with the final volume coming out of the WM12 or the SDC speaker.  It simply wasn't loud enough and I am a young (ish ?) bloke with very good hearing and only just starting to lose the ability to hear the higher pitch sounds when compared to my kids.  At least the WM12 could be placed near the ear, the SDC speaker was just hopeless among dry leaf litter or next to run water or when the wind kicked up a bit. 

That is what I meant when I said that I am surprised the audio is not better.   The quality of the audio getting to the WM12 might be great but the volume of the sound coming out of the speaker isn't.  Unless of course you turn up detector Volume and Target Volume and then you start impacting audio quality as you pointed out. The fact that the flagship detector from Minelab needs any sort of aftermarket booster is poor.

Alternatively, I can also see that there might be improvements in the future for Minelab models as the volume coming from the Gold Monster and Equinox is fantastic.  And the Equinox with its multitude of connectivity options is amazing.  Even future WM12 models could simply have the volume control of the Pro-Sonic unit added (although why this wasn't built in originally perplexes me).

So yes, I am sure you are right that Minelab does prioritise its audio quality, but if that quality audio can't find its way to my ear so that I can actually hear it then they are missing the mark. 

NE  ?

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