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-   -   Let's lobby for switchable audio metering (https://www.dvinfo.net/forum/all-things-audio/47314-lets-lobby-switchable-audio-metering.html)

David Ennis July 7th, 2005 06:02 AM

Let's lobby for switchable audio metering
 
It would be great if anyone who attends shows and speaks to cam manufacturer reps and executives would suggest and promote dual function (i.e., input level / recording level) audio meters on prosumer cams. It should be relatively simple for them to implement and oh, so useful.

[EDIT: Jack's post below my original post has prompted me to be clearer:

Cams like the GL2, PD170 and others that have manual audio control also have lcd level meters. These meters indicate recording level so that you don't overload the A/D converter and produce clipping by exceeding 0 dB.

However, another place that you can produce clipping is at the input. Some mics (or other sources) are too hot for some inputs. The level meters give no indication of what's happening at the input. This is unintuitive. It's all too common a scenario for people wind up with clipped audio and wonder how that could happen when they were diligently watching the recording level.

Yes, you can detect clipping if you monitor properly with headphones, but why not set up to avoid it to begin with? Plus, how often have you wondered what level feed you were getting from a board, or wondered during a performance if someone had changed it at the board? It would be very useful to have a switch (physical or in the menu) that would toggle the function of the level meters between recording level and input level. Setup would then procede thus:

A. switch meter function to "input", check to see that you have an acceptable input level. Add attenuation or make other external adjustments as necessary

B. switch meter function to "record", adjust the cam's gain controls for - 12 dB or other desired nominal level. ]


Wouldn't that be nice?

Jack Smith July 7th, 2005 09:44 PM

Maybe I don't understand Fred, but it sounds(no pun intended) like my XL1S does what your asking.

David Ennis July 7th, 2005 11:08 PM

Quote:

Originally Posted by Jack Smith
Maybe I don't understand Fred, but it sounds(no pun intended) like my XL1S does what your asking.

Thanks for the reply, but no, I checked the XL1s manual online. It doesn't do what I have in mind. I revised my original post above to be clearer.

Steve House July 8th, 2005 04:01 AM

Quote:

Originally Posted by Fred Retread
Thanks for the reply, but no, I checked the XL1s manual online. It doesn't do what I have in mind. I revised my original post above to be clearer.

Sounds like you are thinking of something similar to the trim controls and clipping indicators on the input strips of a conventional mixer so you can avoid overloading the input. I agree it would be a great idea. Alas, audio performance is often an afterthought for camera designers I think. You can get it partially by using a good quality external mixer and of course going all the way to double system lets you choose equipment that lets you properly stage gains all the way through the chain. Would be nice to be able to do that when recording in camera.

I wonder if this would be the proper approach to setup in lieu of camera input clipping indicators or meters hwen using an external mixer? Put the camera on manual audio gain, of course and set its levels to maximum. Feed tone to the external mixer's input and set the mixer's level to read 0VU on its own meters. Adjust the mixer output trim if it's variable or insert attentuation in the line to the camera so the camera's meters read 0dBFS.

David Ennis July 8th, 2005 08:14 AM

Quote:

Originally Posted by Steve House
Sounds like you are thinking of something similar to the trim controls and clipping indicators on the input strips of a conventional mixer...

Steve, actually the existing meters on the cams I'm talking about are more capable than an LED segment that lights up for clipped peaks--they could be made to show you how close you are running to the ideal (nominal) input level, and/or how close you are to clipping.
Quote:

Originally Posted by Steve House
I wonder if this would be the proper approach to setup in lieu of camera input clipping indicators or meters when using an external mixer.....?

That would be a good topic for another thread.

Jeremy Davidson July 8th, 2005 08:47 AM

Fred, I like the clip LED idea. Switchable meters, however, could mean double the ADC circuitry in the camera as right now the meters are probably just a software extention off of the camera's record ADC's. These extra ADC's would likely draw a signal off after the preamp but before the level control. The signal before the preamp may be just too weak to measure directly (granted, I'm kinda winging it here on the theory).

The clip light could be implemented with a fairly inexpensive amount of hardware (we're talking <$20 for DIY-style components) -- actual cost will vary based on R&D for designing and miniaturizing the circuit, etc. etc. etc....

On that note, what about a DIY box with just a couple of clip lights? Since the threshold at which the camera's preamps clip is always the same (regardless of level controls), a little trial and error could yield an indicator that lights at close to the same level. 'Just build the box inline with the miniplug (for example, mic->BeachTek->DIY clip box->camera). I'm thinking specifically of the GL2 here.

My rule of thumb is to still always monitor with headphones, though.

David Ennis July 8th, 2005 04:30 PM

Good points all, Jeremy, thanks. As a matter of fact, I could just tap into the miniplug cable with a multimeter and get all the info I want. I'd still like to see the input issue addressed somehow by a cam feature, though. I've probably responded to a dozen posts by victims.

Douglas Spotted Eagle July 8th, 2005 06:27 PM

It would indeed be somewhat useful to have an input/"output (record) level switch. However....if I could have a nickel for anytime anyone says that it only costs a tiny bit, little bit, nothing, virtually nothing, very inexpensive....to implement, add, or change a product, I'd be a rich, rich guy.
Figure every 1.00 added to manufacturing hard cost adds approx $50.00 (fifty) dollars in actual costs, and therefore a minimum of $100.00 at retail.

Nothing is cheap, and nothing is as easy as it seems. Butterfly effect and a number of other things play into the equation. Figure additional tech support, marketing adds, and more.

While I can see somewhat useful purposes for this, this isn't something I've ever had an issue with. Learn your meters, and they'll serve you well. My only "wish-for" in the camcorder realm, is a clipping indicator, and/or a -3dB indicator that would flash, based on my input as to whether I'd like clipping or -dB. This would be mostly a software extension, but still not cheap/easy to implement.

Jeremy Davidson July 8th, 2005 07:22 PM

Quote:

Originally Posted by Fred Retread
I've probably responded to a dozen posts by victims.

Yes, I was likely one of them.

DSE, those are some good points to remember as well: Know your gear (including its quirks). Also, thanks for the note about the "butterfly effect." My figures were only based (roughly) on parts costs.... but that's what makes DIY projects so great.

David Ennis July 8th, 2005 07:48 PM

I might have been a little glib, but not thoughtless; I did hedge with "should" and qualify with "relatively," anticipating the possibiltiy of a response like Jeremy's. And remember, audio meters themselves, along with many other features were only suggestions at some point.

Speaking of glibness, Doug, show me a company that actually gets $50 increases in wholesale prices for incremental increases of $1 in parts and labor and we can invest and both get rich :0)

Douglas Spotted Eagle July 8th, 2005 09:40 PM

Fred, those numbers are fairly actual, and might even be a little low. Many years ago when I was working as an engineer for a large touring sound company, I spent several days in training with Marty McCann from Peavey. Marty made a comment that I thought was pretty stupid, because I'd asked about why a particular monitoring console couldn't have silver topped knobs vs painted plastic. Other knobs on the console already had the silver. He whipped out a slide rule (yeah, remember those?) and demonstrated that the extra nickel those things cost would add nearly 40.00 to the end cost, due to any number of reasons. So, like an idiot, I challenged his statement later on when we were in the presence of Hartley Peavey. I got a lecture in length of roughly 20 minutes on how this all breaks down. I've never forgotten it.
Recently in the Sony forums, someone who was a product manager at Ford made a similar post, demonstrating how a particular piece of trim could increase the cost of a car by nearly 300.00 for a sub 50.00 part.

In the world of mass production, robots, inventory....I guess that holds true. At my level of "manufacturing" it surely doesn't. I can't count the number of dead cats I've made for .75 and had them sound better than the 50.00 product that you see in catalogs. Maybe I should go into business and find out why these margins work the way they do?:-) After all, we just sell software that you can download.

David Ennis July 9th, 2005 10:04 AM

Doug, the 6:1 or so ratio of the car example squares with my own manufacturing experience better than 50:1 does. Clearly we're dealing with a variable here that can take on widely divergent values.

Maybe it really was 50:1 in the case of your anecdote, but I submit that top execs tend to be high powered, persuasive, articulate individuals who enjoy the process of making an impression. I've been around a lot of them. Peavey would be gratified :)

But, overall point taken. I don't dispute that the retail cost of dual function metering could be a lot higher than my guess. And being able to choose an additional trigger point below 0 dB for an LED input inicator would indeed be enough for me too.


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