Audio Signal-to-Noise Ratio not that great on HMC150

R

richardh

New member
A little background.

I help with a podcast where we do interviews but recently we started doing videos also. Audio is the most important thing we focus on.

I have been using a Canon consumer HD hf200 camera that was only $500. The audio was ok running into it but there was some noise. To get the best audio quality I have been running my mics into a sound board with USB out and recording it to a computer. In post I would then sync the audio to the video which resulted in very clean audio.

To make things a little easier with the audio and to get better video I just bought a new HMC150. I figured since it had XLR inputs that we could get clean audio into this so I would not have to set up the whole mixer and computer system since we usually only use 2 mics.

After recording some samples on the HMC150, I was surprised how much audio noise there was. I have used a few different mics including the onboard and Rode NTG-2 and was still getting hiss. Just for fun I unplugged the mics so nothing was plugged in and had it just record inputs 1 and 2 and was surprised by the amount of noise that gets recorded when nothing is plugged in. I get the same level of noise if I turn down the audio inputs all the way or select Line Level ins (I thought it might be cheap mic pre-amps in the camera).

I use Sony Vegas to edit my video and when I record with nothing plugged in and the inputs turned all the way down the noise shows up as -60db in Sony Vegas.

My cheap hf200 shows up as -74db with nothing connected to it and about -68db with my mic running live in a quiet room.

My mixer setup will show up as -70db with a live mic running in quiet room.

Also there seems to be more higher frequency noise with the HMC150.

I have been thinking about getting the HMC150 or the Sony HXR-NX5U but went with the HMC150 since it was about $800 cheaper.

Anybody else notice the audio noise that is on the HMC150?

If anybody has access to a Sony HXR-NX5U, it would be great if you could record a 5 second clip with nothing plugged into the inputs and send me the raw file so I can check out the audio Signal-to-Noise Ratio.
 
If you have to increase the gain by 40db to really make the noise apparent for some people, then how big of an issue is this really?
 
subtleinspiration said:
If you have to increase the gain by 40db to really make the noise apparent for some people, then how big of an issue is this really?
Click to expand...

You can easily tell with the first file if you have headphones on. I just made the 2nd one so it would be super obvious.

I noticed it right away when I plug in my headphones into the camera. I am just surprised that our cheap camera had a better audio signal-to-noise ratio.

Maybe I have been doing audio work to long.
 
You wanna try recording a loud audio source through the 150! Like live bands, as I do. The audio is littered with pops and crackles no matter the levels.

If you look back in the earlier threads, you will find many questions, and NO ANSWERS about the sound quality on these cameras.

I use 2 different digital audio recorders at my shoots, and mix them later w/ the 150's audio only as a reference.

A very sore spot for me on an otherwise great box.
 
Just keep studying up on audio. You will get the hang of it.

The HMC-150 is about the same as all the similar priced cameras for audio.

If you are fanatical about the audio, forget about the awful onboard mics and the NTG-2 and get a digital audio recorder and some good mics appropriate for your use.

There are posts just like this on the Dvinfo audio forum from people with high end audio recording gear who dont yet understand the basics.

Keep reading.
 
Sounds to me like you're using a "Radio Shack" (aka cheap) XLR cable. Try an Audio Technica or better cable and that sound may go away.

There are a lot of variables going on here -- hardware, software, your skill level -- so all anyone can do is guess. Bottom line -- I don't have this problem, and have never had this problem with the HMC150. Years back something like this was solved on an HVX by replacing the XLR cable with a better brand.
 
AGMedia said:
Sounds to me like you're using a "Radio Shack" (aka cheap) XLR cable. Try an Audio Technica or better cable and that sound may go away.

There are a lot of variables going on here -- hardware, software, your skill level -- so all anyone can do is guess. Bottom line -- I don't have this problem, and have never had this problem with the HMC150. Years back something like this was solved on an HVX by replacing the XLR cable with a better brand.
Click to expand...

The thing is that it shows up with no cable attached and no mic. Just have the inputs on Input 1 and Input 2. I have a few different mic cables and one is "Monster Cable - SL-X-3 StudioLink XL" and tried a few others.

Maybe it is just my camera? I am getting a Sony from a friend tomorrow and seeing what the noise level on that one is.

If somebody could just post 5 seconds of the raw mts file with the inputs on 1/2 with no mic and cables, then I can compare to see if it is maybe my camera only.

If I was editing music and stuff over it all, it would not be that big of a deal. The thing is that is I am recording interviews with it and many people will be listening to the audio only so it needs to be at least as clean as my current audio only setup up.
 
ronedee said:
You wanna try recording a loud audio source through the 150! Like live bands, as I do. The audio is littered with pops and crackles no matter the levels.

If you look back in the earlier threads, you will find many questions, and NO ANSWERS about the sound quality on these cameras.

A very sore spot for me on an otherwise great box.
Click to expand...

There have been answers! To summarize my earlier posts:

1) Noise on the HMC150 is significantly louder than on the HVX200 or DVX100. Hard to tell, when cranking sound up in post, how much of the problem is the HMCs compression and how much is just analog noise. But they both contribute.

2) The HMC has a pretty low INPUT clipping threshold. This is clipping that occurs before the preamp, and before the limiter. This is what explains the clipping sounds that occur when the meters indicate no clipping. The HMC needs pads for inputs that the HVX/DVX handles without a problem. Somewhere, I posted the actual input level that makes the HMC clip regardless of gain settings... but I'm in too much of a hurry now to hunt it down. IIRC, keeping the gain dial at 1 dot below 12 o'clock is the safe position... that is, wit that or a higher gain setting, a line-level input will clip at the OUTPUT (and on the meters, etc) before it clips at the input. Any lower level and you're in danger of the input clipping without any indication. So: the HMC needs to be fed lower input levels than you may be used to, and you need to think of input clipping as well as output clipping.

I don't generally use the HMC for any critical audio; I make sure to use the HVX for almost any situation where the camera will be the only audio recording device (and in general, I record double system).
 
richardh said:
The thing is that it shows up with no cable attached and no mic. Just have the inputs on Input 1 and Input 2. I have a few different mic cables and one is "Monster Cable - SL-X-3 StudioLink XL" and tried a few others.

Maybe it is just my camera? I am getting a Sony from a friend tomorrow and seeing what the noise level on that one is.

If somebody could just post 5 seconds of the raw mts file with the inputs on 1/2 with no mic and cables, then I can compare to see if it is maybe my camera only.

If I was editing music and stuff over it all, it would not be that big of a deal. The thing is that is I am recording interviews with it and many people will be listening to the audio only so it needs to be at least as clean as my current audio only setup up.
Click to expand...


No camera audio will be as clean as even a fairly cheap dedicated audio device. I've compared even such things as a MicroTrack with various camcorders with "good audio", and the MT blows 'em away. A camera is an electronically noisy environment in which audio is not the primary concern.

That said, open inputs is not the best way to test the self-noise of a device with balanced connectors; these will often be noisier with nothing connected than when connected to properly balanced equipment. To properly test self-noise, you need to put some kind of load (typically 150 ohms) across the signal pins (typically 2 and 3) of the input.
 
ullanta said:
No camera audio will be as clean as even a fairly cheap dedicated audio device. I've compared even such things as a MicroTrack with various camcorders with "good audio", and the MT blows 'em away. A camera is an electronically noisy environment in which audio is not the primary concern.
[/quote

Thanks for the input!

I plan on getting a Zoom H4n and recording the interview audio on that and just sync it up in post. I was hoping that I could do everything with the camera.

ullanta said:
That said, open inputs is not the best way to test the self-noise of a device with balanced connectors; these will often be noisier with nothing connected than when connected to properly balanced equipment. To properly test self-noise, you need to put some kind of load (typically 150 ohms) across the signal pins (typically 2 and 3) of the input.
Click to expand...

I thought the same thing and thought that maybe since I turned down the inputs all the way on the camera that it would give me a good idea on how much audio noise the camera generates all its own.

I plan on doing some more testing today and will be picking up a Sony Tape Based HDV camera (not sure of the model since I don't have it right now) and do some comparison.
Click to expand...
 
ullanta said:
There have been answers! To summarize my earlier posts:

1) Noise on the HMC150 is significantly louder than on the HVX200 or DVX100. Hard to tell, when cranking sound up in post, how much of the problem is the HMCs compression and how much is just analog noise. But they both contribute.

2) The HMC has a pretty low INPUT clipping threshold. This is clipping that occurs before the preamp, and before the limiter. This is what explains the clipping sounds that occur when the meters indicate no clipping. The HMC needs pads for inputs that the HVX/DVX handles without a problem. Somewhere, I posted the actual input level that makes the HMC clip regardless of gain settings... but I'm in too much of a hurry now to hunt it down. IIRC, keeping the gain dial at 1 dot below 12 o'clock is the safe position... that is, wit that or a higher gain setting, a line-level input will clip at the OUTPUT (and on the meters, etc) before it clips at the input. Any lower level and you're in danger of the input clipping without any indication. So: the HMC needs to be fed lower input levels than you may be used to, and you need to think of input clipping as well as output clipping.

I don't generally use the HMC for any critical audio; I make sure to use the HVX for almost any situation where the camera will be the only audio recording device (and in general, I record double system).
Click to expand...


I've tried many things and still get the "clipping", at loud events at most any level almost down to nothing!

I think we kicked this around last year at this time. It seems to me that SPL's (sound pressure levels)are the problem. The inputs, or pre's just can't take the pressure of the signal before, or during attenuation. Whether it's circuitry, bad pre's or software? Who knows? Not enough complaints for Panny to care! And rightly so, I guess. How many of us are recording loud bands?

The best luck I've had was with two shure 57's. It seems the dynamic mics buffer, or pad the inputs. BUT...they sound like poop! Very flat and uncolored. Which might be good in some ways, but outboards are unwieldly and clumsy.

So, I use a 4 track Zoom H4 for the room with 4 highend condensers, and a Roland multi-track digital at the mixer. I turn down the cameras audio to a whisper.

I've had it with experimenting. I can't rely on the HMC's sound at my loud events, and just deal with it accordingly.

I'm sorry, but Panny missed on the audio on this series of cameras as far as I'm concerned. Whether you do loud stuff or not...you still want to know your box can handle anything thrown your way!:kali:
 
Ive never had any issues with the audio as far as clicking and popping etc. Ive recorded everything from musicians to dialog. My main go to mic is the AKG CK93. So far so good.
 
Just got done doing some testing. I borrowed a friends Sony HVR-V1U. With the same mic and cable plugged in, the Sony HVR-V1U was about -10 db difference. It was showing up as -70db where the HMC150 was about -60db. Not a huge difference but I could tell the difference while listening.

I am guessing that none of these cameras are going to be as good as a standalone recording device. Looks like I will be getting myself a Zoom H4n and just sync up everything later.

I am just surprised that my Canon Consumer HF200 camera has a better signal-to-noise ratio than the HMC150 and it is about the same as the Sony HVR-V1U. Of course it does not have balanced XLR inputs as you are going to have more hassles with long mic runs and other noises that can get introduced.
 
matt s. said:
Ive never had any issues with the audio as far as clicking and popping etc. Ive recorded everything from musicians to dialog. My main go to mic is the AKG CK93. So far so good.
Click to expand...

I'm talking Rock Band's over a 100db. Which is probably asking too much. That's the reason I live w/ it.

Here is a study in the audio adventures of the HMC

http://dvxuser.com/V6/showthread.php?t=165151&highlight=pops

http://dvxuser.com/V6/showthread.php?t=159737&highlight=pops

http://dvxuser.com/V6/showthread.php?t=158131&highlight=pops
 
ronedee said:
I've tried many things and still get the "clipping", at loud events at most any level almost down to nothing!

I think we kicked this around last year at this time. It seems to me that SPL's (sound pressure levels)are the problem. The inputs, or pre's just can't take the pressure of the signal before, or during attenuation....
Click to expand...

That's what I'm saying... you need to attenuate the signal BEFORE it hits the HMC. If you can borrow or buy a couple of in-line pads (A-T makes some 10-20-30dB switchable ones, I think, that are nice), you may (or may not!) find it interesting to test with mics with hotter outputs than the Shures....
 
I don't have the noise problem you describe on my 150. The headphone jack noise is a known issue, but it doesn't translate into noise in the recording. I have also had XLR feeds directly into the 150 from a sound board, with no noise level problems. An example you can listen to is at http://www.youtube.com/watch?v=eWHMfy38XwU. This concert was earsplitting, way too loud, well over 100 decibels, but the feed of the board was fine, as you can hear. I've also just recently shot a live concert off the board and you can see/hear the results at www.centrum.org front page. While I could have mixed it better, there's no noticeable noise I can hear. Other examples of 'wild' sound off live speakers are at 8stringthing on youtube, which includes recordings of bands at Wintergrass without use of the sound board. Given a good solid sound man, you should be able to record wild stuff just fine. The real problem is trying to record ear splitting noise thats marketed as music. But there are ways to get it done, since even jet engines can be recorded. I just use earplugs and miminize my time in these concerts, as you go deaf from the low end stuff and the high end. There's no hiding from the ear damage.

I've recently bought a mixpre and love it. It feeds me a 1 kHz tone so I can properly balance my incoming sound, and have yet to have it clip on me at the camera. It was well worth the money, IMHO. I also have a Zoom and can feed the Zoom with the MixPre while recording onto the 150. And you can put headphones into the Mixpre if you don't like the noise on the 150 jack. This all allows me maximum flexibility in post. But even the Zoom is a 'low end' recording device, and has known problems which you can find by Googling it. You might step up to a higher end field recorder, like from SD, edirol or Sony. And remember to record at 48 kHz!
 
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8string said:
I've recently bought a mixpre and love it. It feeds me a 1 kHz tone so I can properly balance my incoming sound, and have yet to have it clip on me at the camera. It was well worth the money, IMHO.
Click to expand...

I also use a Sound Devices MixPre with my HMC-150, and I agree that it is one of the best audio buys you can add to your production kit. ( and it runs all day on 2 rechargeable AA batteries )

When adding a digital audio recorder, I would recommend the Olympus LS-11 ( $400 ) or the Sony PCM-M10 ( $300 ), both great recorders, will run all day on one set of batteries. The Olympus has better mics, the Sony is a bit quieter. ( 80+ dB dynamic range with the Sony, 70+ dB dynamic range with the Olympus, 60+ dB range with the HMC-150 )
 
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