Booster Speaker Information

[Jonathan Porter]

I recently posted this to another forum and thought it might help benefit others and maybe generate some interesting discussion here.

A booster can only amplify whatever the detector audio delivers no matter what anyone try’s to tell you. The inbuilt booster speaker system in the Minelab GPX 4500, GPX 5000 is too coarse for effective use via the Target Volume control, this same control is also used on the GPZ 7000 in conjunction with the WM12 and is also too coarse! 

I originally popularised the booster speaker concept when developing a series of instructional videos, looking for a way to obtain good audio that allowed ambient noise of a goldfields environment to also come through so viewers could experience as close as possible the way a detector sounds when in use. In conjunction with this I also discovered the benefits of removing the immediate audio from your ears and placing it further away allowing faint signals to come through (similar to a Television sounding loud in the kitchen compared to being right in front of it). Our ears are designed to collect sound, especially sound that is further away, our ears are also more sensitive to variation in pitch similar to our eyes are to movement so being able to hear the threshold at all times as a reference point is very important, but not at the expense of those around you and small target signals.

The aim with a booster speaker is to lift up the overall volume of faint deep targets without drowning everything else out, as such in less trashy sites a higher volume can be used in conjunction with the correct threshold level. You need to set the volume to compliment the threshold, which needs to be smooth and stable, if someone can hear your threshold miles away you’re doing it all wrong and negating any advantage as well as driving other operators around you nuts.

Best way to go is to set the detectors settings to be smooth and stable, I tend to use conservative Sensitivity/Gain settings along with Volume and Threshold. The Target Volume needs to be kept low to allow the booster to drive the audio without causing distortion, this is especially important on the GPZ 7000. If your detector Target Volume is set to aggressively the booster is then going to amplify that aggressive distorted audio. The threshold needs to be smooth to the ear to start with, if it stutters the amplifier will exacerbate that, if it is too loud it will drown the audio as you boost it.

The B&Z booster is best used for single or twin speakers, it has a very good range of amplification with hardly any distortion. This is especially important because you need to use the booster to adjust the overall audio to suit the ambient noise conditions, in quiet conditions you lower the booster volume so the threshold is not dominating, if its windy then you increase the volume so the threshold can be clearly heard.

The B&Z booster runs on 2 x AAA alkaline batteries which should last up to 3 weeks at 6 to 8 hours per day, it is in a plastic housing to cut down on any excess metal on your body. The B&Z can be used with headphones, to do so the volume of the detector needs to be lowered so the booster volume can be lifted above 2 1/2 to 3 to avoid noise and hiss from the potentiometer, with the GPX and GPZ machines this can be as low as 6 or even lower if required depending on the sensitivity of the headphones being used.

Higher tones tend to require less volume, lower tones more, lower tones (30 and down on Minelab PIs and ZVT) are generally better heard through headphones rather than speakers, this is due to all the natural low frequency noises heard in natural ambient environments, Noise cancelling headphones really compliment low frequency Tones.

The audio of the Minelab GPX and GPZ machines is converted to analogue via the speakers, boosted speakers tend to iron out the steppy digital nature of the Minelab audio, this helps a lot with running less noise floor filtering through the Stabilizer or Audio Smoothing controls, which is were all the edge of detection depth performance lays. The B&Z only ever magnifies the pure audio of the detector with no colouring of the audio through filtering, you only ever hear the “pure” audio intended by the designer of the metal detector. Call me a purist but that’s the way I prefer to hear my detector.

Hope this helps
JP

[Norvic]

Firstly I believe boosters and their use is a personal thing thus we probably all have varying opinions on their usefulness, from believing they are of little use to believing they are the bees knees. I`ve gone from the last extreme to the first over the years. Currently not using one, nor headphones, Using the wireless speaker system of the Z, CTX and the Pro-sonic on the modded SDC. Love the freedom these give, no headphone, no wires, although I must confess took me awhile to go away from the headphone, thought that`s just that young fella JPs fad.

Am I leaving gold, crikey of course I am, would a booster/enhancer change that, no of course it wont.  Dug around in the "old can`t throw away stuff" and gathered what I could find as per below.

 

[Jonathan Porter]

Using the WM12 on the GPZ is akin to using a Booster/Speaker just with less control. I too use the WM12 but I plug my B&Z into it, so I also can enjoy the benefits of being wireless.

JP

[fredmason]

I have always used boosters, starting with Depthmaster headphones....I have had several and like Jonathan Porter's the very best! I have switched to the wm, the Booster and my Sony over the ear-buds...that way I don't broadcast my every target.

Of course, I still have the speakers in case I get back to Australia...

Thanks for the memo, Jonathan---a little reminder is always good.

fred

[fredmason]

Well, that is a hard question, Phrunt!

I actually hard the BZ BOOSTER before JP bought the rights to it...nonetheless, Jonathan uses it and definitely understands how to wring the stuffing from his detectors. When I grow up I want to be just like him, but, not quite that big-haha.

I like the volume control...when following his direction I can increase the volume without getting raspy, harsh noises. I am very sensitive to noise that does not belong so I do what I can to control it...so far, the answer has been the BZ Booster.

15 minutes ago, phrunt said:

is that a stepped attenuator for the volume control, as in are there just 4 or 8 volume levels or something instead of fine volume control, not like a normal potentiometer volume knob or just the sticker just make it look like that?

I don't know as I have very few brain cells and don't waste them on techno-stuff...I think it just turns the volume up or down like a radio knob...

I am not knocking any other enhancer, have not seen or tried the sp01-I am sure it works.

I have enough detecting stuff...so, until they make a really awesome detector that walks, talks and digs; I have enough!

freddy

[Northeast]

1 hour ago, phrunt said:

Is that a stepped attenuator for the volume control

Fred and I seem to have a similar level of technology prowess ?  The B&Z volume control could be described as an infinite control I think, rather than stepped.  There are not just 8 click, click, click settings but you can let the control rest anywhere from Off to Max. 

I liked the B&Z on the GPZ simply for the volume control.  B&Z got sold with the Z though. 

Again I am not a techno wiz but I didn't hear or be annoyed by any hiss or buzz that people mention when they talk about boosters.   Of course my cerebral audio processing functions are probably quite inferior to others  ?

[Norvic]

2 hours ago, phrunt said:

What made you stop using Boosters Norvic? what made you think they're of little use?  Or were they just annoying with another thing to charge and extra wires and so on.

Well I guess it is time related. I used many boosters/enhancers over the years, more then the photo shows, I believed they helped me find more gold. Then I became more "relaxed" comfortable in my ability, perhaps even arrogantly confident. Once I reached that stage I got back to basics, realised by far for me the best approach to getting more gold was keep it simple (KISS), then when the Z came out, no more wires hanging around, things plugged in, wireless all the way  and further to that I got rid of a lot of other preconceived ideas I`d formed over the years eg. where to look.

I still carry a booster/enhancer in my vehicle because I know for success in this hobby one has to keep an open mind. 

[Reg Wilson]

Different boosters react differently to various speakers, headphones and earbuds. While giving a background hum or hiss on one system, on another the audio may be fine. Transmitters too can effect the performance of boosters, and the consensus of opinion seems to be that any booster should be on the RX rather than the TX.

I guess it is a matter of taste, as some people find boosters beneficial, while others do not.

[Reg Wilson]

Well Simon, there will be many who don't agree with me (nothing unusual) but like Norvic I don't use them these days. As pointed out by a well known Australian prospecting personality, boosters cannot create a signal that the detector has not already recognized and audibly responded to.

In earlier days of the VLF detectors, some had a volume that seemed a bit soft, so signal enhancers were widely used to boost the response, however the latest generation of pulse induction machines have more volume control, and generally do not require further enhancement. I prefer to have noise reduction to eliminate distracting outside sound, and even 'white noise' that is not even noticeable until noise cancelling is switched on. Most of the WiFi systems, which I favor have, have a volume control, with the Sennheiser system having volume control on both the transmitter and the headphones. (These H/phones are not noise cancelling, but very good) With TX volume control and N/C I find I have as good a clear and unobstructed audio as I could wish for.

 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. Maybe some people are partly deaf and need a booster. The way I like to run is with threshold only just there, tone way down low, noise cancelling on, and cordless.

[Jonathan Porter]

On 2/19/2019 at 11:26 AM, phrunt said:

...............I was just thinking perhaps JP had found a benefit to having it stepped, like quickly getting you to your favorite volume level without having to fine tune it like on a more detailed POT volume knob.

 

Volume control on the B&Z is not stepped. Volume is set to suit local ambient noise so generally there is no favourite level. The key is hearing a smooth stable threshold which is then controllled by the booster dependant on external noise levels. In the case of headphones, the booster can also help but depending on the amount of volume the headphones can achieve determines the level of volume you need to put out from the detector, I generally recommend lowering the detectors volume then using the booster to increase the volume to a comfortable level. Some headphones do not reach this critical point no matter how much volume you use on the detector, hence needing the B&Z to get the volume loud enough without increasing/elevating detector noise. I am not a fan of the Volume control on the 7000 or the Target Volume control on the GPX series, they are too steppy and lift the noise floor to unacceptable levels without really improving the fainter targets.

Best bet with headphones is to have a reasonable sized target that gets the detector to reach Max volume when the coil is right on the target and adjust the Volume of the booster there (in the case of the GPX and GPZ start at Target Volume of 8 and be prepared to go lower), then listen to the threshold and confirm if you can hear it clearly, especially any faint variations in the threshold. I usually increase the booster volume a touch till a close to coil target is bordering on slightly uncomfortable, especially if I am working deep ground with minimal trash signals. Adjusting the Target Volume of the detector one point at a time can also help a lot to even out the threshold without affecting the outright max volume.

JP