The gist of my above post was more about explaining why I thought there is a very audible threshold on the GPZ & not much/nothing on the QED. Wasn't really trying to debunk the use of boosters on the QED although it may read like that to some I guess. I've also tried the Nokia MD-11 amplified speaker on the QED which again is ok but not to the audio level of other machines. The Nokia speakers biggest downfall is also the lack of a volume control. I used to use these on the Whites GMT & they worked very well on it.
Have owned & used 2 of your Treasuremate amps/speakers. They are great particularly being an all in one unit. The new set up with rechargeable battery would make it even better as would a replaceable lead - I damaged both mine thru my own fault of straining the lead. Did the same to my first B&Z set up. Wireless is the go :lol: although it could be mounted on the QED ok.
I've owned quite a few different types/brands of boosters/amps including some from China. The only direct comparison I've ever made though was between the Treasuremate & a Rooster Booster on GPX5000. They were much the same but in mine & a mates opinion the Rooster Booster had a bit more volume output in that comparison. While having never compared them directly I always considered the B&Z fairly close to the Rooster Booster.
As I said above the boosters I tried on the QED did improve the audio output level but not the same as you would expect on SDC/GPX/GPZ as the audio input from the QED is very low to start with. It can only be boosted or amplified so much by these types of units so unless you have substantially increased the audio output capabilities of the Treasuremate I'm guessing I would still be a little dissatisfied with the audio level but others may not be.
The headphones I've tried on the QED are Seinheisser HD-280's & RS-160's. Found the Seinheisser HD-280's worked well with the SP01 with being able to set it up to my liking. The filters on the SP01 definately worked better with these headphones in some settings over others. I've since sold the SP01 as I prefer wireless & I could not find a wireless system that the QED using the SP01 would work well with (don't start me on QED/wireless compatibility issues :N: ). These headphones also work fine just plugged directly into the QED without a booster but yes there is increased volume with one.
The best audio set up I've used on the QED to date are the Seinheisser wireless RS-160's that have their own built in volume controls. I tried the boosters with these but there was very little or no noticeable improvement. They are fine just by themselves & what I now exclusively use on the QED.
Maybe a video of your Treasuremate demonstrating the threshold audio level with & without on the same QED settings would help convince me to buy another unit
Edit: p.s. I should also add & haven't made it very clear in either post that my main objective in trying boosters on the QED was to lift the baseline threshold in order to pick up variations easier. Both boosters I tried did lift it a bit but not greatly - as said it's different to the Minelab threshold & very quiet to start with.
Both boosters did lift the obvious target signals as expected - no issue there. That's not the issue I have with the QED audio - its hearing those small breaks in the baseline threshold that is hard to amplify whereas on the Minelab machines because it's more pronounced to start with amplifies more readily which is what I believe is heard in Rick's video with the much louder GPZ threshold over very low/nothing from the QED. It's not some type of trick to discredit the QED that's just how the threshold is.
