"Mixed mode..."

Hi all...

I keep seeing reference to "mixed mode" as a type of detecting option on some machines in some recent posts here, and it's a term I am not familiar with. Can someone enlighten me, and discuss the pros/cons/benefits of such a mode -- when it might be used in a hunting situation?

Thanks, and sorry for the ignorance...

Steve

Hey Steve,

Mixed mode (made famous on the Nautils machines I believe) are when you get to hear a discriminate beep in addition to the all metal sound AT THE SAME TIME (well, usually). On the Nautilus you got the beep in one ear and the all metal sound in the other. It was unique though, in that the type of metal was reflective of how wide the all metal side sounded. Iron was very wide (if memory serves correct.) I'm not sure if other machines had quite the same type of mixed mode. There are variences, like the V3i gave you the option of disc beeps and AM in both ears at the same time, but I don't like that, I like stereo mixed mode - which separates the two sounds e.g. Beep in the left ear, AM in the right.

As Keith said in another thread, mixed mode is great in cleaner areas as it will get you more depth. You know, I'm sure, that all metal goes deeper. So, if you can imagine hearing both all metal and the discriminate beep, I'm sure you can see the possibilities with depth. In areas with lots of targets though, it is just toooooo much to hear. So, most hunters like it in cleaner areas.

From memory, it also give you an instant idea about depth and target size (at least more so or easier than just a disc beep would.

I'm sure others will add more,
Albert

Yes that is pretty much it. I had the feature on my old Eagle Spectrum. It was just too noisy to use in high trash areas. After a half hour your eyeballs would be bouncing to all the chatter. I prefer a zero discrimination myself. With todays tones it is getting easier all the time to do it. True all metal goes deeper, but I don't know of too many detectors with a true all metal and good tone ID.

Albert -- OK, but from your description, I'm having trouble knowing the benefit of the "discriminate beep" along with the all-metal mode. Why is this better than just using all-metal, with NO "discriminate beep?" I'm sure the answer is obvious, but it's not coming to my mind right now. I am guessing you could set your discriminate to "just iron," and then if hunting in all-metal "mixed mode," if you got a tone, but also a "beep," you'd immediately know that the machine THINKS it's iron...but you'd still get the better depth offered by the all-metal mode? Is that it?

goodmore -- now you bring up ANOTHER issue that confuses me -- "true" all-metal mode. Can you (or someone) explain this? I think, when I "open the screen" on my Explorer, and run "no disc," I call this "all-metal mode," but I think it's been said that this is not TRUE all-metal mode. In my mind, I am assuming that since I can get digital ID information in this Explorer "all-metal mode," then that means by definition that the signal coming from the coil is passing through a "filter" or something (is that the correct word?) so as to deduce that ID info, at the expense of some loss of depth? I am assuming that "true all metal mode" means it's the RAW signal coming from the coil? Or, am I mistaken here? This is another of those things that has always been unclear to me.

Thanks to both of you,

Steve

Steve - You are on the right track (and note I'm no expert here... well maybe I am, I did have a Nautilus for years. Ok, I'm an expert ;-) Imagine this, you are running mixed mode with iron discd out (discd out in disc mode, not iron mode - I believe that is how it worked). Well, you get to hear the iron buzz but it doesn't beep on it. That right there tells you the ground iron content. Yeah, discriminate mode can do that alone but you get more flexibility and DEPTH running mixed mode. You also can, depending on the machine, get an idea of target size and depth. Don't forget target size.

You are running SAT (Self adjusting threshold) in mixed mode. That requires some motion and the SAT adjusts according to how you set it - it depends on your swing speed. It's where the threshold resets in a sense. I forget a bit here.

So, for example you are moving along and get the AM sound that is 4 inches wide and a beep in the center. Further the beep is high tone. Now you have an idea of target size (more than just a discriminate beep would give the average hunter - unless you got a lot of time on your machine) and the type of target. The volume of the iron is informative regarding depth. There is just more info there.

I would like to hear from some of the gurus on mixed mode out there. Remember, I'm no Guru, just an expert. (Def of expert - more knowledge than the average detectorist (in this case) for a certain feature). I think Keith is quite versed in mixed mode. I mean he got that accent for starters ;-)

Wow...many things here I'm not familiar with -- SAT, "volume of the iron," etc. I follow you, though, regarding the sizing that is possible in all-metals, vs. just "a beep" in disc. mode. I know what you mean there, and it makes sense about the "more info" that would concievably be available in a "mixed mode."

Thanks, Albert...

Steve

Only mixed mode I am familiar with is with Whites Spectrum...XLT series,,,Certainly not for junky areas as you would need excedrin about every 15 minutes as the noise would drive you crazy....benefits it will certainly go deeper as nothing is disced out...and will grab a nice target next to perhaps a piece of junk that would mask it in regular mode..
As far as the Nautilus all I know its the favorite of the Southern fellows for relic hunting...
The book Spectrum Secrets gives the best explanation of mixed mode audio in Whites units that I ever read..

Yes, I remember the mixed mode on my Nautilus too. One side was all metal the other was disc, it was on my V3 too, never used it.

I run a XLT and an AT Pro and the mix mode on the XLT I alway thought of heearing everything but with tones, and with the AT Pro, it has a iron on or off, I like listening it with the iron on, because I hear the iron and the other metals , it's sort of the same thing, yes or no??

SAT adjusts the time it takes for the detector to recover from one target and be able to detect the next one. That is one of the downfalls of a detector that runs in Autotune ground balance. Hit a trashy enough area and the detector is not recovering from last target registered. Thus one misses alot of stuff. Now this downfall can be circumvented, if detector has ability to adjust SAT threshold as Earthman points out.

Ok now I am confused, I did not realize SAT had any effect on recovery speed or ground balance - hmmm! Oh and correct me if I am wrong but on a Minelab FBS machine there is no SAT and at least to my ears and my memory the Threshold is not really the same animal as other VLF machines. And last I am with Steve what is "true all metal mode"?

Ahh the beauty of a true All metal mode is a thing to behold...and for deep hunting it's the only thing as of yet to get truly deep....Unless you buy a high end P.I.

But a true all metal mode threshold based can either be S.A.T. for simple operation or can be user manually adjusted...the later offers even more depth for more non mineralized ground....

The true all metal mode is completely different from a discrimination mode ran in all metal accept.

When a discimination circuit is in an all metal mode it is still working off of phase shift to determine if it's iron or not...No where near a true all metal mode...And no a Explorer in all metal accept it not a true all metal mode and the theshold is not tied to all metal mode it's a discriination threshold used to monitor rejected target's i.e. null's..

A true all metal based threshold is not sampled through phase shift principal...it's not sampled it's just a true audio report of the target in a raw form...no disc whatsover is involved it hears everything in the gorund down to mineral and bobby pins you name it...

But a true all metal mode is very very deep ...deeper than most people would ever want to dig..and the more minerals present the better depth gain you will see over a dic circuit sometime 40% or more depth in mineral's but it is a dig it all mode...


but it does offer true target shaping depth and to a tuned ear the roundness sound of a good target over a nail.....

It is not designed to be used in a trash area it's for wide open dig it all approach's..Its been around forever and in modern designs it is left off alot fo machines sadly..

If you ever heard of me and others state I dug a coin size target at say 15-18 inches deep ...well it was not done in a disc circuit...it was done with 20 year old machines running a threshold based all metal mode..

Now what is treshold based...

a threshold is a background hum the detector generate's..and you have a threshold control to adjust it to barely audible setting..get it to just barely hum ..set it too low and target's at depth will be missed set it to high target's at depth will be missed...as it is set to purr right along you listen for a rise and fall of a signal...A waiver of the threshold is what you look for you will hear it start rise and go down...if the trshold is a bit too high the rise and fall will be lost ..if it's set a little higher and the target is deep it the peak of the signal will be lost also..

The S.A.T. Speed is what readjust the threshold back to the original setting...the slower the deeper the machien will go butt takes longer to retune...it will stay quite after a traget is encountered for a second or two according to speed set...if it's fast it looses depth but retunes also quicker after a target is encountered almost instantly...

Why would you want it fast then...well in ground with lot's of mineral it helps maintain and smooth out the threshold over varying ground mineral to a degree...and a Prospctor uses this type of mode for looking for nugget's...He knows a disc circuit in bad ground will cancel a raw gold nugget so all metal mode with an audible threshold with a fast retune for the mineral content of the gold fields will get him the good's other machines will not with a disc circuit..

a general use machine will have a medium S.A.T. threshold speed and be very effective...One of my favorite's is medium...The white's 5900 di pro sl...

Deepest seeking vlf all metal detector I have ever encountered..It also has a mode for manual Threshold retune if the gorund is good enough...when it drift's off and it will you bring it back with a simple trigger pull...

A good running All metal Mode Vlf will out perform any Disc circuit for depth when understood and used properly and tuned right in medium to bad dirt..and in good dirt it can still eek out alittle more depth over a hot disc circuit...

but remember there's no disc...

I am not a fan of dicrimination foe deep hunting..after decades of testing in the dirt you would be amazed at what even a very low disc setting leaves in the ground being I.D,d as iron..

Keith

Holy COW Keith. What an outstanding explanation. And it REALLY makes sense, now.

So, question...is there a GOOD discriminating machine out there, that can be switched into a GOOD, true all-metal mode -- i.e. a machine that does both jobs, well?

Steve

My x-terra 70 and the newer 705 has a prospecting mode which is a true all metal mode ,will give a nice digable signal on faint targets that the disc circuit calls iron.,turns it from an ok machine into a killer machine.

after reading Keith's post, I want to go back to all my sites and dig every iron signal, I hunt places that I know stuff is there, but don't dig anything, I'm digging iron for now on