Audio from the PDX10 at DVinfo.net

Amir Shehata · January 1st, 2004, 12:56 AM

Hi,

Happy new year to all...

I have been filming with the PDX10 and I'm satisfied with it thus far, but the audio has proven way harder to control than the picture.

I found that everything I record has a constant hissing noise. I guess that's the best way to discribe it. It's not from the environment where I am recording, but it seems to be some sort of feed back. I hope I'm explaining myself clearly. It doesn't interfere with the mic picking up sounds, but when I capture onto my computer the sounds are not crisp. They are always accompanied with that hiss, and in total silence, the hiss is there. Constant and never ending.

Is there a way to get rid of it while recording? or in post?

thanks in advance.

Frank Granovski · January 1st, 2004, 03:28 AM

There shouldn't be hissing with the PDX10. Perhaps play around with the settings a bit. If that doesn't prove useful, send it in for warranty work.

Boyd Ostroff · January 1st, 2004, 09:04 AM

Yeah, sorry but no idea on this unless there's actually a problem with your camera. Is the XLR hotshoe connector firmly seated? Try some tests; do you get the hiss if you record from a line level input? Can you try a different mike? Unplug the mike and see how much hiss you get with no input at all. How about if you remove the XLR box completely and use the internal mikes? Do you get the hiss on both manual and auto settings? How high are you turning the gain? If you crank it up full I'm sure there will be hiss (like any amplifier), but under normal circumstances you shouldn't notice it. When you are recording, what sort of levels show (when you push the audio level button)?

My experience with the PDX-10 is that the audio is extremely clean and there is no hiss at all. If you decide to send the camera in for warranty service then it will be helpful to try these various things and note the results so that you can document the problem.

Amir Shehata · January 1st, 2004, 02:14 PM

I tried both the internal mic and the XLR input, both exhibit the same behavior.

Like I said that hiss doesn't interfere with the recording, and it doesn't register on the sound meter.

I tried a different test. I completely unplug the mic from the XLR adaptor, and the hiss is still there. I hear it by connecting a headphone to the camera, or when I connect the camera to my computer via firewire.

The hiss is reduced when I reduce the CH1 and CH2 gain.

The question is, is this a defect?

I remember before buying my camera, I went to a local shop and tried out their PDX10. I recorded some footage from their camera, and I can still hear that hiss.

Note: This hiss is not static. It's constant feed, that doesn't vary.

thanks

Boyd Ostroff · January 1st, 2004, 04:48 PM

I just plugged my Sony MDR-V600 headphones into my PDX-10 and tried a few things with mic level on "auto". I'm using the builtin mikes and put the camera about 18" away from my computer, pointed towards it. The ambient fan noise and room tone registers at around -28dB. As I type this the clickity clack of the computer keys registers as high as -10 dB.

Now using the + and - buttons under the screen I set the monitor volume to about the middle of its range. Through the headphones the computer fan and hard drives sound like a factory roar and my keystrokes sound like tap dancing ;-) But any "hiss" is way, way below this level and can't be heard at all. If I turn the monitor volume up any higher it becomes unpleasant, then painfully loud.

Now I put the XLR block on the camera and unplug the mic so there is no input. I leave the monitor volume at its 50% setting. I really don't hear any perceptible hiss. Now if I press the headphones really tight to my head I hear a very quiet sort of humming or rumbling noise actually.

With no input connected I raise the headphone montor level to the max, now I hear some hiss, and a periodic sort of strange rumble. But remember, this monitor level was actually painful when the meters read -10dB, so this noise is way, way below the recorded signal.

And I also wonder how much of this is coming from the headphone pre-amp on the camera? Somewhere I read a sony tech note (although maybe intended for the PD-150?) stating not to use the headphone jack for critical audio judgement.

Tell us how you're listening to the audio. Are you plugging headphones into the jack on your camera in all these cases? Where is the monitor volume level set? What sort of headphones? Depending on impedance you might have to turn the volume up higher than mine. Try plugging in the AV cable into the yellow miniplug, then plug the L and R audio into an amplifier that you know is good. Do you hear the hiss there? Have you tried capturing to your computer, then sending through firewire to a different device (like another camcorder, DV deck, DVD recorder) and listening?

Lots of questions! One thing that could cause this would be recording at too low a level I'd think. Are you set on auto or manual? What do the peaks read at?

When taping our operas I fed one channel from the house sound board at line level, and used the other channel for the camera mounted mike. When the theatre was empty I could hear very noticeable noise coming from the balanced XLR line to the soundboard, but the on camera mike sounded really clean. In other words, the camera itself had a noticeably better signal to noise ratio than the house sound system. But again, all this noise was way below normal audio levels. Both channels as recorded in performance sounded really good, and I like the audio quality much more than my VX-2000.

Amir Shehata · January 2nd, 2004, 12:18 AM

Hi Boyd,

Thanks for taking the time to help in this matter. I really appreciate it.

Here is what I tried:

1. When I'm filming I always use the headphones to monitor the audio. In order for me to be able to do that I turn the gain on both CH1 and CH2 to the max. I also crank the volume to the max. (BTW all my settings are manual). At this setting, I can hear a hiss/humm that's constant. But it doesn't interfere with the audio. I mean I can hear the slightest motion around me, even me breathing.

2. I transfer the scenes I film onto my computer and play them back. I still hear that humm/hiss pretty clearly if I turn the volume up.

3. I connected my camera to my TV via the A/V jack. The problem with that, if I turn the volume on my TV too high, there is a very loud whine. I think that's some sort of feedback.

4. I connect my camera to my Computer and view live what the camera is shooting on my computer. I still can hear the humm/hiss.

Now, inorder to be on the same page, i have uploaded two sample audio clips on my website:
+ silence - a silent clip. (so you can hear the humm/hiss)
+ speech - some chatting.
Both those clips were captured by my PDX10. If you have sometime you can download them and hear them, so that you'd hear what I'm talking about. They are pretty small, so they shouldn't take you too long to download.

The samples can be found at:
http://www.stop-n-read.com/TheJonahRedemption.htm

The problem is that I don't have much equipment to test with. All I have is my PDX10, computer and a TV. So I'm limited with the equipment I can test with.

If it is possible, can you upload a short sample audio file, so that I can hear how your audio sounds.

Thanks very much for you help

Boyd Ostroff · January 2nd, 2004, 10:44 AM

Amir: I listened to the "silence" and "speech" clips. If I turn up the volume on the silence clip I can hear a hiss, but it isn't especially loud IMO. On the speech clip, the hiss seems to be well below the room tone/camera noise, and the voices are way above all that.

So there doesn't really seem that anything is particularly wrong to me, but that is very subjective of course. I uploaded a very short uncompressed 44k audio clip for you. It's a quiet section from the opera "Susannah" that we recently did. Now this is a mix of the camera-mounted mike and house sound board feed, so there is other noise introduced. I picked a quiet section so you could hear any background noise, but since this has been mixed, etc. I don't really know how useful it will be. You will probably need Quicktime to hear this clip if you're on a PC. It can be downloaded at http://www.apple.com/quicktime/products/qt/. The audio clip can be found here:

http://greenmist.com/susannah.mov

When you say "In order for me to be able to do that I turn the gain on both CH1 and CH2 to the max. I also crank the volume to the max", I'm wondering what you mean? Do you mean that you have to turn up the mike levels to the max? And also turn up the monitor volume to the max? Where does it register on your audio meters?

This doesn't sound quite right to me. You should set the mike level so it doesn't overload, then you should be able to monitor with headphones by setting the monitor level around the middle. If it doesn't sound loud enough in your headphones then I suspect you need to get lower impedance phones. Check the specs on your headphones, and read some of the threads on dvinfo.net about headphones. If they aren't matched to your camera's preamp then they won't ever seem loud enough.

Unfortunately this is about as far as I can go with all this since I have a number of other projects to work on... maybe someone else has helpful ideas? If you really feel something is wrong with the camera then send it back while it's still under warranty and ask them to bring the audio up to spec. Good luck!

Amir Shehata · January 2nd, 2004, 12:25 PM

Hi Boyd...

Thanks for your help.

After listening to the clip you uploaded, I can still hear the hum in the background. Maybe I'm being hypersensitive to the whole thing. Or it could very well be something with my headphones. I will check them.

By turning the gain on the CH1 and CH2 up, I meant basically pressing the "AUDIO LEVEL" button then turning up the CH1 and CH2 levels to the max. Then I press the "VOLUME" button on the side of the camera until the max.

Anyway, I appreciate all your help. By now I don't think there is anything particularly wrong with the Camera.

Oh, and the Operas that you are involved in sound really good, from the small clip I listened to. Are they sold any where? I'd like to listen to a whole one.

thanks

Boyd Ostroff · January 2nd, 2004, 12:44 PM

Like I said before, if you have to turn the audio levels up to the max all the time then something is strange. If you set the levels to "auto" (using the menus) what happens? Does it sound too soft? Are you basing these judgements on the sound from your headphones? Like I said, you should be able to set the volume level of your headphones (using the + and - buttons) such that it sounds loud enough around the middle of the scale. See if you can find the impedance rating of your phones, mine are rated at 45 ohms.

But it seems that maybe you are being a little oversensitive to the hum/hiss thing. Although if you're recording with the gain at the max and monitoring with the volume at the max then that is probably introducing additional noise. See if you can try the same tests on some other brand/model of camcorder as a reference. I'm of the opinion that the PDX-10 audio is quite nice, especially considering the price and inherent limitations of DV.

Unfortunately we don't sell recordings of our shows, and union contracts prohibit distributing anything significant. We do audio broadcasts locally for each opera on WRTI in Philadelphia. Not sure, but these might be available on the internet.

Happy new year, and good luck with your quest for cleaner audio. Unfortunately this isn't really a field where I have much experience, so it's hard for me to give you any definitive answers. Maybe you should ask some more general questions about what to expect from camcorder audio in the Now Hear This forum?

January 1st, 2004, 12:56 AM	#1
Amir Shehata New Boot Join Date: Nov 2003 Location: Canada Posts: 24	Audio from the PDX10 Hi, Happy new year to all... I have been filming with the PDX10 and I'm satisfied with it thus far, but the audio has proven way harder to control than the picture. I found that everything I record has a constant hissing noise. I guess that's the best way to discribe it. It's not from the environment where I am recording, but it seems to be some sort of feed back. I hope I'm explaining myself clearly. It doesn't interfere with the mic picking up sounds, but when I capture onto my computer the sounds are not crisp. They are always accompanied with that hiss, and in total silence, the hiss is there. Constant and never ending. Is there a way to get rid of it while recording? or in post? thanks in advance. __________________ Amir Shehata

January 1st, 2004, 02:14 PM	#4
Amir Shehata New Boot Join Date: Nov 2003 Location: Canada Posts: 24	I tried both the internal mic and the XLR input, both exhibit the same behavior. Like I said that hiss doesn't interfere with the recording, and it doesn't register on the sound meter. I tried a different test. I completely unplug the mic from the XLR adaptor, and the hiss is still there. I hear it by connecting a headphone to the camera, or when I connect the camera to my computer via firewire. The hiss is reduced when I reduce the CH1 and CH2 gain. The question is, is this a defect? I remember before buying my camera, I went to a local shop and tried out their PDX10. I recorded some footage from their camera, and I can still hear that hiss. Note: This hiss is not static. It's constant feed, that doesn't vary. thanks __________________ Amir Shehata

January 2nd, 2004, 12:18 AM	#6
Amir Shehata New Boot Join Date: Nov 2003 Location: Canada Posts: 24	Hi Boyd, Thanks for taking the time to help in this matter. I really appreciate it. Here is what I tried: 1. When I'm filming I always use the headphones to monitor the audio. In order for me to be able to do that I turn the gain on both CH1 and CH2 to the max. I also crank the volume to the max. (BTW all my settings are manual). At this setting, I can hear a hiss/humm that's constant. But it doesn't interfere with the audio. I mean I can hear the slightest motion around me, even me breathing. 2. I transfer the scenes I film onto my computer and play them back. I still hear that humm/hiss pretty clearly if I turn the volume up. 3. I connected my camera to my TV via the A/V jack. The problem with that, if I turn the volume on my TV too high, there is a very loud whine. I think that's some sort of feedback. 4. I connect my camera to my Computer and view live what the camera is shooting on my computer. I still can hear the humm/hiss. Now, inorder to be on the same page, i have uploaded two sample audio clips on my website: + silence - a silent clip. (so you can hear the humm/hiss) + speech - some chatting. Both those clips were captured by my PDX10. If you have sometime you can download them and hear them, so that you'd hear what I'm talking about. They are pretty small, so they shouldn't take you too long to download. The samples can be found at: http://www.stop-n-read.com/TheJonahRedemption.htm The problem is that I don't have much equipment to test with. All I have is my PDX10, computer and a TV. So I'm limited with the equipment I can test with. If it is possible, can you upload a short sample audio file, so that I can hear how your audio sounds. Thanks very much for you help __________________ Amir Shehata

January 2nd, 2004, 12:25 PM	#8
Amir Shehata New Boot Join Date: Nov 2003 Location: Canada Posts: 24	Hi Boyd... Thanks for your help. After listening to the clip you uploaded, I can still hear the hum in the background. Maybe I'm being hypersensitive to the whole thing. Or it could very well be something with my headphones. I will check them. By turning the gain on the CH1 and CH2 up, I meant basically pressing the "AUDIO LEVEL" button then turning up the CH1 and CH2 levels to the max. Then I press the "VOLUME" button on the side of the camera until the max. Anyway, I appreciate all your help. By now I don't think there is anything particularly wrong with the Camera. Oh, and the Operas that you are involved in sound really good, from the small clip I listened to. Are they sold any where? I'd like to listen to a whole one. thanks __________________ Amir Shehata

January 1st, 2004, 03:28 AM	#2
Frank Granovski Outer Circle Join Date: May 2002 Location: Hope, BC Posts: 7,524	There shouldn't be hissing with the PDX10. Perhaps play around with the settings a bit. If that doesn't prove useful, send it in for warranty work.

January 1st, 2004, 09:04 AM	#3
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,787	Yeah, sorry but no idea on this unless there's actually a problem with your camera. Is the XLR hotshoe connector firmly seated? Try some tests; do you get the hiss if you record from a line level input? Can you try a different mike? Unplug the mike and see how much hiss you get with no input at all. How about if you remove the XLR box completely and use the internal mikes? Do you get the hiss on both manual and auto settings? How high are you turning the gain? If you crank it up full I'm sure there will be hiss (like any amplifier), but under normal circumstances you shouldn't notice it. When you are recording, what sort of levels show (when you push the audio level button)? My experience with the PDX-10 is that the audio is extremely clean and there is no hiss at all. If you decide to send the camera in for warranty service then it will be helpful to try these various things and note the results so that you can document the problem.

January 1st, 2004, 04:48 PM	#5
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,787	I just plugged my Sony MDR-V600 headphones into my PDX-10 and tried a few things with mic level on "auto". I'm using the builtin mikes and put the camera about 18" away from my computer, pointed towards it. The ambient fan noise and room tone registers at around -28dB. As I type this the clickity clack of the computer keys registers as high as -10 dB. Now using the + and - buttons under the screen I set the monitor volume to about the middle of its range. Through the headphones the computer fan and hard drives sound like a factory roar and my keystrokes sound like tap dancing ;-) But any "hiss" is way, way below this level and can't be heard at all. If I turn the monitor volume up any higher it becomes unpleasant, then painfully loud. Now I put the XLR block on the camera and unplug the mic so there is no input. I leave the monitor volume at its 50% setting. I really don't hear any perceptible hiss. Now if I press the headphones really tight to my head I hear a very quiet sort of humming or rumbling noise actually. With no input connected I raise the headphone montor level to the max, now I hear some hiss, and a periodic sort of strange rumble. But remember, this monitor level was actually painful when the meters read -10dB, so this noise is way, way below the recorded signal. And I also wonder how much of this is coming from the headphone pre-amp on the camera? Somewhere I read a sony tech note (although maybe intended for the PD-150?) stating not to use the headphone jack for critical audio judgement. Tell us how you're listening to the audio. Are you plugging headphones into the jack on your camera in all these cases? Where is the monitor volume level set? What sort of headphones? Depending on impedance you might have to turn the volume up higher than mine. Try plugging in the AV cable into the yellow miniplug, then plug the L and R audio into an amplifier that you know is good. Do you hear the hiss there? Have you tried capturing to your computer, then sending through firewire to a different device (like another camcorder, DV deck, DVD recorder) and listening? Lots of questions! One thing that could cause this would be recording at too low a level I'd think. Are you set on auto or manual? What do the peaks read at? When taping our operas I fed one channel from the house sound board at line level, and used the other channel for the camera mounted mike. When the theatre was empty I could hear very noticeable noise coming from the balanced XLR line to the soundboard, but the on camera mike sounded really clean. In other words, the camera itself had a noticeably better signal to noise ratio than the house sound system. But again, all this noise was way below normal audio levels. Both channels as recorded in performance sounded really good, and I like the audio quality much more than my VX-2000.

January 2nd, 2004, 10:44 AM	#7
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,787	Amir: I listened to the "silence" and "speech" clips. If I turn up the volume on the silence clip I can hear a hiss, but it isn't especially loud IMO. On the speech clip, the hiss seems to be well below the room tone/camera noise, and the voices are way above all that. So there doesn't really seem that anything is particularly wrong to me, but that is very subjective of course. I uploaded a very short uncompressed 44k audio clip for you. It's a quiet section from the opera "Susannah" that we recently did. Now this is a mix of the camera-mounted mike and house sound board feed, so there is other noise introduced. I picked a quiet section so you could hear any background noise, but since this has been mixed, etc. I don't really know how useful it will be. You will probably need Quicktime to hear this clip if you're on a PC. It can be downloaded at http://www.apple.com/quicktime/products/qt/. The audio clip can be found here: http://greenmist.com/susannah.mov When you say "In order for me to be able to do that I turn the gain on both CH1 and CH2 to the max. I also crank the volume to the max", I'm wondering what you mean? Do you mean that you have to turn up the mike levels to the max? And also turn up the monitor volume to the max? Where does it register on your audio meters? This doesn't sound quite right to me. You should set the mike level so it doesn't overload, then you should be able to monitor with headphones by setting the monitor level around the middle. If it doesn't sound loud enough in your headphones then I suspect you need to get lower impedance phones. Check the specs on your headphones, and read some of the threads on dvinfo.net about headphones. If they aren't matched to your camera's preamp then they won't ever seem loud enough. Unfortunately this is about as far as I can go with all this since I have a number of other projects to work on... maybe someone else has helpful ideas? If you really feel something is wrong with the camera then send it back while it's still under warranty and ask them to bring the audio up to spec. Good luck!

January 2nd, 2004, 12:44 PM	#9
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,787	Like I said before, if you have to turn the audio levels up to the max all the time then something is strange. If you set the levels to "auto" (using the menus) what happens? Does it sound too soft? Are you basing these judgements on the sound from your headphones? Like I said, you should be able to set the volume level of your headphones (using the + and - buttons) such that it sounds loud enough around the middle of the scale. See if you can find the impedance rating of your phones, mine are rated at 45 ohms. But it seems that maybe you are being a little oversensitive to the hum/hiss thing. Although if you're recording with the gain at the max and monitoring with the volume at the max then that is probably introducing additional noise. See if you can try the same tests on some other brand/model of camcorder as a reference. I'm of the opinion that the PDX-10 audio is quite nice, especially considering the price and inherent limitations of DV. Unfortunately we don't sell recordings of our shows, and union contracts prohibit distributing anything significant. We do audio broadcasts locally for each opera on WRTI in Philadelphia. Not sure, but these might be available on the internet. Happy new year, and good luck with your quest for cleaner audio. Unfortunately this isn't really a field where I have much experience, so it's hard for me to give you any definitive answers. Maybe you should ask some more general questions about what to expect from camcorder audio in the Now Hear This forum?