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Who would be interested in this device?


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#1 Scot McPhie

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Posted 29 July 2006 - 10:09 PM

A friend of mine who is an electronics engineer/nerd/genius has proposed the following audio device:

An ad on box which in real time does three things:

1 Resolves the audio to a given frame rate in real time, based on a sycnh pulse input from the camera

2 Uses a sensor attached to the camera body to get a reference signal which is used to subtract or reduce the camera noise from the final audio signal

3. Acts as a DI box to interface your balanced microphone to a recording device

The processing will be achieved by DSP processing in the unit.

The next question is how much would people be prepard to pay for this - and how much demand for it is there?

All questions and input appreciated.

Scot
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#2 Keneu Luca

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Posted 29 July 2006 - 11:45 PM

A friend of mine who is an electronics engineer/nerd/genius has proposed the following audio device:

An ad on box which in real time does three things:

1 Resolves the audio to a given frame rate in real time, based on a sycnh pulse input from the camera

2 Uses a sensor attached to the camera body to get a reference signal which is used to subtract or reduce the camera noise from the final audio signal

3. Acts as a DI box to interface your balanced microphone to a recording device

The processing will be achieved by DSP processing in the unit.

The next question is how much would people be prepard to pay for this - and how much demand for it is there?

All questions and input appreciated.

Scot


Sounds intersting. But I think a prototype is required to evaluate it's actual results before a price can be given.

Is there a protoype?
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#3 Scot McPhie

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Posted 30 July 2006 - 02:04 AM

Sounds intersting. But I think a prototype is required to evaluate it's actual results before a price can be given.

Is there a protoype?


Not yet - the purpose of the email is to gauge interest/demand in it - the rough price given is based on experience from other devices he has made - it's given as a guide to see how much interest there would be in the unit as this price range. I agree you can't get an actual idea until a prototype is done and a set price is established.

None the less I'm keen to hear people's thoughts.

Scot
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#4 Michael Collier

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Posted 30 July 2006 - 03:01 AM

1 Resolves the audio to a given frame rate in real time, based on a sycnh pulse input from the camera


Sounds like almost any professional audio deck. you have a timecode-sync machine. Audio decks are expected to do this. The key is to be able to ensure your timecode matches that on the tape without error, so sync is always maintained. Sometimes the camera can't provide timecode, so timecode generation is expected from a higher end model, otherwise it should jam to whatever signal it is presented with.

2 Uses a sensor attached to the camera body to get a reference signal which is used to subtract or reduce the camera noise from the final audio signal


The sensor attaced the the camera is not neccisarry. XLR is a ballance signal, so all that has to be done is an op-amp be attached to the signal and inverse signal. The result is the noise that both lines gained. run that through the preamps feedback system (pre-amp type A i beleive, but its been a while since I was into EE) Since noise is introduced equally to all lines in the transmitting cable, most noise can be reduced. Keep in mind that if you plan to run a mic directly from your box, you must have at least the following: 48v phantom power, and a pre-amp circut that emphasizes quality and provides wide overhead for times when the mic gets really hot (usually in rare very breif spikes. such as when a hard 'P' sound is hit.) linearity is also a concern.

3. Acts as a DI box to interface your balanced microphone to a recording device


Your DAs should be of at least 24bit/96KHz for professional level recording. They should also be made with high-quality resistors and be mounted close on the board the the pre-amp circut (sheilding probably is neccisary) It would be cool if you could experiment with a higher bit-rate, given the state of memory today. If you went to 64 bit you could have a much higher head-room allowing truer recordings when the mic is hot. Imagine shooting a scene where the whispers rest in the first 24 bits, and the yelling that follows doesn't clip. I hear from some guys that they prefer analog recording to digital sound recording because it holds the hot mic better. (sorta sounds like the film/video debate)

The processing will be achieved by DSP processing in the unit.


Not much proccessing should be needed. An EQ (that is easy to adjust) and a compressor/limiter would probably be all that is needed. I would make sure that if it records to a hard drive or flash memory that you have a provision to add a filename. Better yet, a simple system to add meta-data to locate the time, date, production, scene, page, take. Also if possible for ease of use a buffer of about a second so when you hit record, there is no lag time before the memory is ready (also useful if the memory lags).


The next question is how much would people be prepard to pay for this - and how much demand for it is there?


Pay could be on a sliding scale. I have seen recorders like the fostex F2 recorder for between 1300 and 2000 depending on options, but a good industry quality recorder could get up to 3 or 4 grand (or more with more channels/options.) The main deciding factor for your products success is its robustness and ease of use. If effects are too hard to access or edit they are a hit against your product. If a knob or swith is flimsy or improperly placed, nobody will want to use it. There also must be something about your product that makes professionals excited about your device. Chances are your customers allready have a workflow that works for them. If they upgrade they expect it to be much easier, and digital recorders are pretty easy to use as it is.
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#5 Scot McPhie

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Posted 30 July 2006 - 05:39 AM

Thanks for your lengthy reply Michael it is much appreciated - however you completely misunderstand what we are trying to do. I'll explain with reference to your quotes:

Sounds like almost any professional audio deck. you have a timecode-sync machine. Audio decks are expected to do this. The key is to be able to ensure your timecode matches that on the tape without error, so sync is always maintained. Sometimes the camera can't provide timecode, so timecode generation is expected from a higher end model, otherwise it should jam to whatever signal it is presented with.


It is not a pro-audio deck or time code synch machine. It is for use with non crystal synched cameras in which the frame rate constantly drifts by small amounts above or below the set frame rate (eg 25 fps +/- 0.2% randomly). By getting a pulse from the camera each time a frame is exposed we have a reference point which we can use to shrink or expand the corresponding portion of the recorded dialogue so that when the film is transferred at an exact 25fps in telecine the recorded dialogue will match it and be in synch. This can already be done by software but we are looking at a way of doing it in hardware on the fly as it is recorded, thus simplifying the post route. There is no time code recorded.


The sensor attaced the the camera is not neccisarry. XLR is a ballance signal, so all that has to be done is an op-amp be attached to the signal and inverse signal. The result is the noise that both lines gained. run that through the preamps feedback system (pre-amp type A i beleive, but its been a while since I was into EE) Since noise is introduced equally to all lines in the transmitting cable, most noise can be reduced. Keep in mind that if you plan to run a mic directly from your box, you must have at least the following: 48v phantom power, and a pre-amp circut that emphasizes quality and provides wide overhead for times when the mic gets really hot (usually in rare very breif spikes. such as when a hard 'P' sound is hit.) linearity is also a concern.


It's not a sensor to balance out noise in the line - but rather a sensor to sample the camera sound - ie the actual whirring/clicking sound the camera makes when running - so we can then use that to try and cancel or reduce that sound from the recorded dialogue.



Your DAs should be of at least 24bit/96KHz for professional level recording. They should also be made with high-quality resistors and be mounted close on the board the the pre-amp circut (sheilding probably is neccisary) It would be cool if you could experiment with a higher bit-rate, given the state of memory today. If you went to 64 bit you could have a much higher head-room allowing truer recordings when the mic is hot. Imagine shooting a scene where the whispers rest in the first 24 bits, and the yelling that follows doesn't clip. I hear from some guys that they prefer analog recording to digital sound recording because it holds the hot mic better. (sorta sounds like the film/video debate)


Agreed the bit rate and Hz should be high.

Not much proccessing should be needed. An EQ (that is easy to adjust) and a compressor/limiter would probably be all that is needed. I would make sure that if it records to a hard drive or flash memory that you have a provision to add a filename. Better yet, a simple system to add meta-data to locate the time, date, production, scene, page, take. Also if possible for ease of use a buffer of about a second so when you hit record, there is no lag time before the memory is ready (also useful if the memory lags).
Pay could be on a sliding scale. I have seen recorders like the fostex F2 recorder for between 1300 and 2000 depending on options, but a good industry quality recorder could get up to 3 or 4 grand (or more with more channels/options.) The main deciding factor for your products success is its robustness and ease of use. If effects are too hard to access or edit they are a hit against your product. If a knob or swith is flimsy or improperly placed, nobody will want to use it. There also must be something about your product that makes professionals excited about your device. Chances are your customers allready have a workflow that works for them. If they upgrade they expect it to be much easier, and digital recorders are pretty easy to use as it is.


As you've probably realised by now alot of processing will be needed and it's not a recording device - but something that treats the sound and is then passed out for a recording device that the user can choose.

Scot
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#6 paulhanssen

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Posted 30 July 2006 - 08:19 AM

I would be interested, mainly because of point 2. But I suppose this reducing will be done real time. While reducing in post would be better, so that one has something left to choose or adjust at ones own will, and does not have to decide everything in real time.

As for the price, generally I think this should be a low budget device; since that's what most of us are. I think, if it works, and has a compact size, I don't think I will go over a hundred.

Isn't there any good stand alone software available for reducing unwanted noises???

P.S.

I have seperate devices already for 1 and 3.

I respect people generating new ideas though.

Paul
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#7 Scot McPhie

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Posted 30 July 2006 - 04:43 PM

I would be interested, mainly because of point 2. But I suppose this reducing will be done real time. While reducing in post would be better, so that one has something left to choose or adjust at ones own will, and does not have to decide everything in real time.

As for the price, generally I think this should be a low budget device; since that's what most of us are. I think, if it works, and has a compact size, I don't think I will go over a hundred.

Isn't there any good stand alone software available for reducing unwanted noises???

P.S.

I have seperate devices already for 1 and 3.

I respect people generating new ideas though.

Paul

Hi Paul thanks for that - I appreciate the desire to be able to experiment/adjust sttings in post rather than on the spot as it were.

Just put of interest what is your device for point 1 - as far as I know this can only be done now in post by software - or do you have another method which adequately gives you synch (eg pilot-tone top tape recorder, or crytal synch camera to begin with?)

Scot
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#8 Brian Wells

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Posted 30 July 2006 - 05:28 PM

Does anyone actually record sound with Super8? Phase cancellation of the camera noise is a novel idea, but it seems to me that anyone with money to spend would be shooting on a quiet S8 or even S16 camera and not have any need for a device that cancels out the motor noise. In any case, most peripheral noises can be mitigated by simply using the microphone away from the camera. If the microphone is mounted on the camera, sure, it can be tough to get good audio. But, by simply using the directional microphone on a boom pole pointed away from the camera, motor noise (on video or film) is dramatically reduced because of the effectiveness of the shotgun mic design. I still think a phase cancellation device for mitigating motor noise is a cool idea. I just can't imagine anyone using it for Super8 filmmaking. In_My_Opinion. Keep it up.
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#9 Chris Keth

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Posted 30 July 2006 - 06:37 PM

Does anyone actually record sound with Super8? Phase cancellation of the camera noise is a novel idea, but it seems to me that anyone with money to spend would be shooting on a quiet S8 or even S16 camera and not have any need for a device that cancels out the motor noise. In any case, most peripheral noises can be mitigated by simply using the microphone away from the camera. If the microphone is mounted on the camera, sure, it can be tough to get good audio. But, by simply using the directional microphone on a boom pole pointed away from the camera, motor noise (on video or film) is dramatically reduced because of the effectiveness of the shotgun mic design. I still think a phase cancellation device for mitigating motor noise is a cool idea. I just can't imagine anyone using it for Super8 filmmaking. In_My_Opinion. Keep it up.



The problem here is that the cost of this device would be high enough that the filmmaker in question could just use a sync camera and not worry about all that crap. Nice problem-solving though.
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#10 Chris Graham

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Posted 30 July 2006 - 11:19 PM

I guess it's beneficial to have something that would cancel out the motor noise, but there are several ways/cheats oto overcome camera noise. When you think about it, zoomed close-ups are a huge way to cheat out the motorized sound. I have footage in which I shot a scene in a busy office with many cubicles. Person A on the left and B on the right with office printers, phones ringing, people on phones, just realistic office noise in which I didn't even need to use the wild track. lots of compensating of cuts, cheats, made the scene work and not even notice the drag of frames2lips. That was without the crystal sync too! In the end and point being, you couldn't hear the camera. With a distance of 20ft, tight medium shot, boom unoticed as usual. Everything came out great. Obvious idea is to overcome camera noise and distances from the gun. But anyhow those are just cheats that I just do. But the whole sync'd cancellation is a good idea. Make the prototype, show results, and hey I might buy! And I'm aware that you're referring to close to camera shooting. Funny how shooting far is a style within itself.

Edited by ShootStr8, 30 July 2006 - 11:20 PM.

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#11 paulhanssen

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Posted 31 July 2006 - 01:49 PM

Hi Paul thanks for that - I appreciate the desire to be able to experiment/adjust sttings in post rather than on the spot as it were.

Just put of interest what is your device for point 1 - as far as I know this can only be done now in post by software - or do you have another method which adequately gives you synch (eg pilot-tone top tape recorder, or crytal synch camera to begin with?)

Scot


hello scot,

I use Pedro's 1000Hz pulse generator for point 1.

best regards,

Paul
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