alfie wrote: ...which point to a lack of total certainty , do they not ? And unless I am mistaken , you have not actually been involved in the design or operation of the snicko device that is used in the drs system.
The system is incredibly simple in scientific/technical terms. I believe I could create a crude reproduction in about 15 minutes given the tools. Its not like hotspot, which is technology used on submarines, if you knew how to use a DAW and could link it to a live picture feed, you could make snicko. There isnt much for the initiated to understand, even if to a lay person it might seem very complex.
Obviously I'm not silly enough to try and argue with you on something that is not my field ; but I do note that you use words such as "unlikely" and " 99.9%" ................
I do not know what extraneous sounds manage to infiltrate the system ; but I am fairly sure I have at times seen small unexplained marks on the snicko visual that are quite clearly nothing to do with the bat. In the case at hand - I haven't yet viewed it back - I had assumed any extra sound was a case of bat on pad , bat on boot ; as many have said it seemed the ball was nowhere near the edge of the bat
There is a chance that the system is compromised, hence the 99.9% certainty. The fact is, a correctly set up snicko system should make it a virtual impossibility for ambient sounds to be filtered into the end result. It simply should not happen. I will try to explain it in easy terms, but I am struggling for a good example.
Say you record a band, standard drums, singer, bass and lead guitar. Each of these instruments will operate on different levels of frequency, which is arguably the reason why this form of music is enjoyable to humans.... you get a range of tones, pitches and sounds that cover the hearing spectrum. You will find that each instrument has a range of different frequencies in itself. Sound is built on "harmonics" and overtones, which are essentially different frequency sounds that make up a whole. Try to hum to yourself in a high pitch, you will notice if you listen carefully there will also be a low bass tone, or possible many layers building that sound of various pitches, of which one dominates, but the others are faintly present. If I were to shove a microphone in the middle of the room and record the band playing, you'd find when playing it back that you get a lot of clashing noises. This is where each instrument crosses over range into each other, and the brain/ear struggles to differentiate between them. It becomes "muddied" as they would say in the industry.
If I wanted to stop that and get the clarity of each instrument being distinct, I could filter the areas they clashed by eradicating them. Say for instance a bass guitar operates at a frequency range of 60-1000hz, and a base drum 20-100hz. You will see in the range of 60-100hz, they will clash. So Id put a filter blocking all frequencies as 60-100hz range, and what you will find is that separates the instruments to sound distinct. You would find the recording would have much more clarity, it would sound much better. You can even to a large extent replicate this at home, if you have a separate amplifier or a hi-fi system with separate "bass, treble, mid" dials, you can control the frequency filter. This is just boosting frequency very crudely and generally through equalization, but if you have one you can play around with it and see the effect of what it does to the different layers of sounds.
If I wanted to remove the bass drum completely from the recording, I could put a filter on the 0-100hz range. As the bass drum doesnt produce any frequencies out of this range, you would no longer hear it, it would be like it wasnt there. Similarly, if I filtered to 12,000hz I would be left with an empty track apart from the occasional cymbal crash.
Snicko works exactly like that. What it does is to say, I only want to hear the range of frequencies that the bat makes, and I filter out everything else. Like the instruments in the band, each of the ambient sounds around it produce their own range of frequencies, but to the advantage of snicko, none of those should be able to produce the same frequency as bat on ball. In the same way a bass drum could never go above 100hz, a keeper scratching his feet, a crowd member shouting, a bat hitting a pad.... they all may share SOME of the frequency range of an edge, but not ALL. You just set the filter to capture the unique frequency. Like the bass drum and guitar that share a huge portion of range, I just set the filter to 1hz range that is unique to the bass drum, and thats all you will hear. If I put that through an oscillator, any movement of the wave is bass drum.
Snicko has an advantage, because I believe in physics energy/intensity is proportional to frequency. Or in other words, the harder you hit something, the higher frequency sounds are produced (it would take me all week to explain that in physics, and I concede im at the limits of my scientific knowledge in doing it). What on a cricket pitch is having a 90mph lump of solid leather thrown at it around the same time? Nothing. So the chances of interference in a practical sense are very limited.
Testing has shown that the ball hitting a bat on the full sweet spot will produce a sound at the lowest frequency of 1500hz. To put this into context, if hypothetically everyone in the crowd had the ability to sing baritone and Mezzo-Soprano at abilities ranking them the best of both fields in the history of music, they would only have a range of 100-1000hz. A filter of 1100hz would completely block out any noise its scientifically possible for any human on the ground to make, and would leave the perfect sound of ball hitting bat. Less perfect contacts on the face of the bat are around 500hz, which is in the same range as humans, but these would still be sufficient contact to not even come close to contesting a visual eye confirmation.
Most importantly, light or feathered contacts at the edges of the bat produce massively higher frequencies. 5,000-3,000 hz. Even more importantly, bat hitting things like the ground or pads in testing operate at far lower levels, 71-177hz on average, so they are nowhere near. Nothing in the ground is capable of producing a sound like that, so in short, a well setup system should make it impossible for any sound to be registered.
Is it possible to produce something of the same frequency range than 5,000hz. Yes, it is possible. One could have a phone with a sin wave playing in the crowd at that frequency. Some jet engines would produce such frequencies. Its worth noting though that higher frequency waves are far more easily absorbed in any medium they travel through, and are far more likely to be reflected from surfaces. And the further away from the microphone, which is no doubt calibrated to a certain sensitivity and focused on picking up sounds in a certain direction or zone around it, even in the unlikely event that it was possible, its verging on impossible it would be picked up by the recording device.