Should the DRS be mandatory?

[sussexpob]

Much of what you say is over my head, sussex - I know nothing at all about synthesisers and the like; I'll have to ponder a little, but it does sound an interesting possibility.

Basically a synthesizer is just something you can create your own soundwave form on which then amplifies the soundwave you have manpulated. At first before manipulation occurs you just get a pulse which creates nothing, much the same as an oscillator which isnt picking up a frequency. By channelling an instrument or a soundbank into the synthesizer you get to to produce an organic soundwave that is triggered by the instrument(in a process called Midi), which you can then play with to create the sound you want.

That soundwave can be anything... the point is that the stump microphone could be plug into a mixer with every frequency filtered expect ones which are unique to the edges you are looking for. This part of the sound wave is then unfiltered and will trigger a reaction in the sound device you want to play a note or noise of your choosing. So snicko could be adapted to form a very simple pre-empting trigger for the umpire.

[DeltaAlpha]

Something like this is what I had in mind:



The left image shows the marble just released, and is the video frame immediately before it has reached the edge of the table; the right image shows the frame immediately after the marble has passed the edge and the waveform shows all the sound in between and lasts 300ms - my camera has a rather slow frame rate.

There is no confusion with animation and trying to guess where the sound occurs, and I think it's pretty clear that the marble has edged the table. Incidentally, I did not hear the sound when the marble did edge the table, but then my hearing's pretty poor at the moment.

Thoughts?

[sussexpob]

Something like this is what I had in mind:

[ [spoiler=image][/spoiler] ]

The left image shows the marble just released, and is the video frame immediately before it has reached the edge of the table; the right image shows the frame immediately after the marble has passed the edge and the waveform shows all the sound in between and lasts 300ms - my camera has a rather slow frame rate.

There is no confusion with animation and trying to guess where the sound occurs, and I think it's pretty clear that the marble has edged the table. Incidentally, I did not hear the sound when the marble did edge the table, but then my hearing's pretty poor at the moment.

Thoughts?

In this instance the sound produced is unquestionably the striking of the table. The soundwave is shaped like thus generally... > ..... which would indicate that the source that has produced the sound has been struck, or the sound was created by contact with something... this contact is also isolated because after a very tiny initial sustain period of the attack phase, the sound decay's rapidly to the point of ambience again, meaning only one point of contact created the sound.

This would be consistent with the pictures, and the level of decay consistent with the surfaces/objects use, and my assumption as to the quality of your acoustic setup(decay is elongated, most likely due to the reverb in the room you are using).

[DeltaAlpha]

Yes, the decay is surprisingly elongated, sussex, but it was done quite close to a wall, which could explain it as you suggest. But, listening to the video on my laptop, I can hear the sound quite clearly and it does sound like a very sharp click. I still haven't managed to upload it to YouTube - it just takes ages to say that the file cannot be processed, and I've tried three different formats so far.

One thing that I should mention is the length of the audio - it's 300ms but should really only be 100ms. This is because I've had to include three frames in the video (there's one before the first one shown) and the frame rate is 10fps. If I only include the two frames, the video plays OK, but I cannot extract the sound to create the waveform. Presumably something to do with video file formats or the software I'm using; I don't think it's a big deal, but it would be nice to do it all the same.

I think it's quite good and convincing, actually, but whether it would be as good in a cricketing environment and entertain TV viewers sufficiently, I'm not so sure!

[DeltaAlpha]

I figured it out... it just needed to be longer:

[youtube]bKRWrH0t0WE[/youtube]

Can it be made to return to the video rather than show ads when it's finished?

[DeltaAlpha]

I've noticed that there are two clicks in the video in the previous post; they're about 0.15s apart, and here's the waveform:



The second looks very different from the first, and I can't really account for it. I wonder if sussex can shed any light on it.

[sussexpob]

DA,

No time to respond yet as left work to go to the bar to watch the end of the series. I will respond tomorrow

[Arthur Crabtree]

They have cricket in the pub in Norway?

[sussexpob]

They have cricket in the pub in Norway?

Premier League is the most popular sport, so bars get English sports channels for the football....in the summer months it just so happens these channels also have cricket on, so on a monday night when no one is around, as long as you are buying some beers in a deserted bar the cricket gets turned on after a polite request.

[sussexpob]

This is where sound engineering turns into full on mechanics, so my terminology and explanation my not be technically brilliant.

Every material has an inclination to respond at greater amplitudes when the frequency of its oscillations match its natural frequency of vibration. This is known as the resonance frequency, and a material can have more than one, the lowest frequency being known as the fundamental frequency. Because of this increased amplitude, even in the presence of other frequencies being created, the sound you hear is dominated by the fundamental frequency's pitch, and any subsequent integer multiple of this frequency also creates a resonant frequency, known as a harmonic.

The reason that the resonance frequency produces greater amplitudes is because of increased energy absorption at these frequencies producing greater vibrations in the material, while less natural frequencies do not absorb as much energy.Because the system responds to small amounts of energy and amplifies certain frequencies, momentum can build up in the vibrating substance producing resonance, which keeps the vibration going.

This is counteracted by friction and damping though, so without reapplication of force that maintains the absorption of energy in the system, eventually the point of equilibrium is reached and the vibration stops. When you think of catastrophic instances of resonance, mainly in the form of the famous bridges that wobble and collapse, there is always a continual application of force/energy, usually in the form of something like the wind.

To put it into context, when the marble strikes the table sound will be produced, amplified at all the levels of frequency that are harmonics of the Fundamental, but also the unamplified overtones that are not part of the fundamental will mix, giving the contact a unique sound.

The second sound cannot be resonance because there is no second source of energy after the striking of the table that replenishes the energy absorbed in that collision that is eventually dampened or lost to friction.

In the soundwave the initial high amplitudes are a mix of your harmonics and overtones, which produces the big crash on contact. After this you can see that the sound sustains at around the same level, and this where your marble is resonating back to the point of equilibrium.

My guess is that it is an interference.... it might have been created as simply as you reaching to turn off the camera, and you pushing air into the microphone with that motion.

[DeltaAlpha]

I understand your description of harmonics, resonance etc., sussex, so that's OK. But the second sound can't be me doing anything to the camera because I wouldn't be able to do that just 0.15s after dropping the marble, but also, the clip is the third of four marbles that I dropped, moving nothing but my fingers, so it isn't the end of the sequence anyway.

I've had a close look at the video and audio of the whole sequence, and there are all sorts of clicks that I can't account for. However, I can see that the first two marbles strike the top of the table rather than edging it, and there is no odd click after either of those, whereas the last two marbles did edge the table and there's another click about the same time after both of those.

It looks to me as though the set up isn't fit for purpose, and I'll have to think again about how to make it better. Even if that is so, though, there is only one click between the two frames showing the marble before and after it edges the table, and that's the important bit.

Anyhow, thanks for your input; maybe I'll be back with some better ideas in a little while.

[sussexpob]

Actually on second thoughts DA it could be reverb. Sometimes with reverb, especially from a surface that reflects a lot of sound, or in a room that has good acoustics, you get a reflection from the contact surface that produces an echo kickback. Rather than a distinct echo, which usually occurs in micro terms a lot longer(but in reality of course a split second), the surface reflects literally 1000's of different frequencies almost instantly.

Because of refraction( I think its that, I maybe wrong, again this is physics not really my area- could be diffraction?) these sound waves united together to generate a high amplitude wave that registers as an interference. It doesnt sound like anything because to a certain extent it is going to be lots of reflected frequencies that united to fom an inorganic sound.

If you are using reverb channels on instruments for instance, often too much saturation in reverb produces a hollow clicking sound almost after the note is struck....

Check for instance the third note here..... can you hear the distinctive and out of place sound?

http://en.wikipedia.org/wiki/File:Rever ... effect.ogg

[DeltaAlpha]

It could be something like that, sussex. I did wonder if it might be some resonance built up in the table top, but there seems to be too much of a delay, though that's only guesswork.

I think one of the problems is that the camera seems to have a built-in automatic volume control - I can even hear myself breathing on the full sequence - so it picks up everything and the amplitude of the waveform isn't a true reflection of the loudness of the sound. What it really needs is a mike plugged into the camera that bypasses the auto volume system; I'm not sure that's possible with my camera, though. I'll have to check.

I was also wondering if an external mike would be better, connected directly to the laptop, but that would stop the sound and video being recorded to the same file, so wouldn't solve the problem of synchronisation, which is what I was trying to do in the first place. So that's a non-starter.

I've also thought of doing a similar thing in the kitchen where the worktops are much harder and less resonant (and less creaky!) than the table, but there would possibly be problems with echoes from the tiled walls, noise from the fridge and so on.

Anyway, it's something to think about since there's no cricket today!

Just seen your reference to Wikipedia, and I can hear the reverb, but isn't that produced electronically and deliberately?

[sussexpob]

I think one of the problems is that the camera seems to have a built-in automatic volume control - I can even hear myself breathing on the full sequence - so it picks up everything and the amplitude of the waveform isn't a true reflection of the loudness of the sound. What it really needs is a mike plugged into the camera that bypasses the auto volume system; I'm not sure that's possible with my camera, though. I'll have to check.

Try bringing the camera closer. If you are say over a foot away you will lose the loudness of the attack frequencies quite a bit, so they are not as distinct as the sustained or decayed sections of the sounds... its worse because the further you are away the more decay and sustain the mike will add too.

I was also wondering if an external mike would be better, connected directly to the laptop, but that would stop the sound and video being recorded to the same file, so wouldn't solve the problem of synchronisation, which is what I was trying to do in the first place. So that's a non-starter.
[/quote

You could always try audacity, that will record the sound through your laptop microphone and record it in soundwave format and its free. If you could trigger the sound and pictures at the same time you could then load the images into something like windows movie maker, with the audacity sound file as the audio channel... its a crude setup, and the problem lies in the trigger of both at the same time. Alternatively you could set the audacity to record first, and synchronize later. Not sure if this helps you though..

I've also thought of doing a similar thing in the kitchen where the worktops are much harder and less resonant (and less creaky!) than the table, but there would possibly be problems with echoes from the tiled walls, noise from the fridge and so on.

If you were serious about it you then you could always try to dampen the reverb sound. Surround the open sides of the table with something like a duvet or some pillows, and this will absorb all the unwanted sounds. I have done this before actually to great effect by encasing a man who strummed his guitar incredibly loudly so that you could hear his plectrum strokes picked up inside the microphone several meters away.... I made him sit inside an encased foam castle which blocked it getting to the microphone!

t seen your reference to Wikipedia, and I can hear the reverb, but isn't that produced electronically and deliberately?

Yes that is no doubt a synthesizer with someone playing with the reverb settings, but it occurs naturally a lot in certain situations

[DeltaAlpha]

Some good ideas there, sussex; I never thought of using duvets, pillows or whatever, so I'll try that. The camera was already quite close, but it could probably be moved closer - the trouble is that I can't be sure where the marble is going to be immediately after edging the table. But recording the sound separately is just what I'm trying to avoid; they must be in the same file and then, from that, the audio can be extracted and will be in sync with the video.

I'll ponder tonight and have a go tomorrow.