Noisy pre-amps, or something else?

Craig Irving · January 7th, 2008, 10:36 AM

http://www.badongo.com/file/7205625

Thanks for your interest everyone.
Here's a wav that shows what I'm getting.

Dan Keaton · January 7th, 2008, 10:48 AM

Craig,

I tried listening to your clip.

I do not have all of my tools available here at my office. Also, my office has normal "Office Noise" making it less than perfect.

However, I could not hear any significant noise.

Could you check your file by downloading it yourself. Then please let me know if you hear the noise.

Steve Oakley · January 7th, 2008, 11:44 AM

I Dl'd your clip but it was silent....

sounds line a power supply problem in the camera. its not physically generated noise... unless the mic pre amp board is literally microphonic from the vibration of the motors running, but that would really be a long shot, although possible with a defective component. sounds far more like the camera's power supply is borderline and when the motors kick in for the tape transport, they start making dirty power because they are on the edge. its also possible that the motors themselves are putting noise into the camera's power, but very very unlikely. sounds like its time to send it in for service.

Daniel Epstein · January 7th, 2008, 02:37 PM

Haven't listened to the clip but your description sounds like the tape transport is creating some electrical noise which is getting into the audio circuitry before it goes to record. I would bring this up with your dealer and the manufacturer directly as it might just be your unit but it also could be a problem with the whole series of cameras.
Also you should record it to tape with out the Harddrive unit connected to make sure it is just coming from the Tape drive

Jeffery Magat · January 7th, 2008, 03:41 PM

There is nothing on that WAV file you uploaded. Not even a single waveform.

We'll need something where you're actually recording audio to see what kind of noise you're getting. Perhaps a snippet of that recording you made on your last shoot?

Jimmy Tuffrey · January 7th, 2008, 04:25 PM

I came across this same problem back in June. That was what brought me to this forum. The noise is there when you record. Also it has a very noisy cheap sounding headphone out. The gain knobs are best left at their centre dent 5 setting too if you want to avoid noise, bit pointless having them.

My final verdict was that the sound of this model camera is poor to worse.

Would be interested in what conclusions you come to. Particularly turning off the lcd.

Why Sony can't sort the audio out on their cameras I don't know. Just used the new DSR 450 and the headphone out has noise and latency. One of three units sounded considerably less bad as well. The phono/line outs are said to be good though as is the recording apparently. Just a crap headphone amp circuit.

Keep us posted on your test results. I was not the pwner and only had limited time to test the model I was using. Recorded double system audio in the end.

Glenn Davidson · January 7th, 2008, 04:39 PM

The clip does have a good sample of the noise, it is just very low level. I imported it into ProTools and raised the gain. Sounds like internally generated camera noise. It consists of a low frequency rhythmic motor boating and a high frequency whine. Can't you get decent Signal/Noise ratio by feeding a good audio signal?

Craig Irving · January 7th, 2008, 05:16 PM

Hey guys.

I re-downloaded that clip from the link I sent I sent you and I'm kinda surprised only a couple of you heard it. You actually shouldn't really need to touch the gain, I was playing back the clip in VLC Player and just boosted the headphone volume and heard it right away, it's constant. Also using the speakers of my laptop (though they're poor quality) it was obvious to me.

It's not really that low-level to me, it's actually quite loud I feel w/ the interview subjects talking.

I opened it in Sound Forge myself to look at it, and immediately I didn't see waveforms either, then I zoomed in quite a bit and did notice a pattern of dots (I really don't know much about spectrum/frequency analysis though)

Here's a picture I posted of how it looks to me in Sound Forge 9.

Glenn Davidson · January 7th, 2008, 05:29 PM

it is -58 db referenced to digital 0. That's pretty low.

Craig Irving · January 7th, 2008, 05:36 PM

http://i75.photobucket.com/albums/i3...seAnalysis.jpg

Craig Irving · January 7th, 2008, 06:03 PM

Hmmm. Alright so I guess my inexperience with audio is starting to show. It seems the consensus is that -58db is a very low level signal, and though I'm hearing a noise in my headphones it sounds like it's to be expected. Although it's confusing that it doesn't sound that low to me in my headphones. I guess I just expected absolute silence, since I can record a clip directly to HDD that doesn't have this silence (though I haven't yet examined it in Sound Forge, I'm still curious to know if it's -58 or something different).

I'm going to be taking all your tips. I have been keeping my gain at around 6-7 (no higher usually). I'll try reducing it even more if I can.

Thanks again everyone for your help, I appreciate you taking the time to download the clip and help me out on this. I really didn't want it to come across as "this is a serious problem" but more along the lines of "this is what I am hearing and should I worry about it" kind of thing.

So I'm glad to hear it's normal.

Dan Keaton · January 12th, 2008, 08:00 AM

Dear Craig,

How did your shoot go?

Dan Brockett · January 12th, 2008, 11:20 AM

Quote:

Originally Posted by Craig Irving

Hmmm. Alright so I guess my inexperience with audio is starting to show. It seems the consensus is that -58db is a very low level signal, and though I'm hearing a noise in my headphones it sounds like it's to be expected. Although it's confusing that it doesn't sound that low to me in my headphones. I guess I just expected absolute silence, since I can record a clip directly to HDD that doesn't have this silence (though I haven't yet examined it in Sound Forge, I'm still curious to know if it's -58 or something different).

I'm going to be taking all your tips. I have been keeping my gain at around 6-7 (no higher usually). I'll try reducing it even more if I can.

Thanks again everyone for your help, I appreciate you taking the time to download the clip and help me out on this. I really didn't want it to come across as "this is a serious problem" but more along the lines of "this is what I am hearing and should I worry about it" kind of thing.

So I'm glad to hear it's normal.

Hi Craig:

Just to let you know, Sony Corporation has a proud and cherished lineage of selling consumer and prosumer camcorders with amazingly bad sound quality. I owned a TRV-900 for about 10 years and it was sent to Sony Service for new microphones, new audio pre-amps and new circuitry and it still sounded terrible, Sony would just mark on the service papers, "acceptable sound quality for consumer camera", which didn't help.

The PD-150/VX2000 and PD-170/VX2100 were widely acknowledged as the worse sounding prosumer camcorders that had ever been sold. Hiss, noise, low dynamic range, they had it all. It's interesting, since Sony went to HDV, I have not heard many complaints about the sound quality until your post. I shot with a Z1 for the past few years before I bought an HVX and the Z1 had okay, if not great sound quality.

This doesn't help you solve your issue and you should realize, based upon past history, there may be no way to solve this issue. Sony acknowledged that the PD-150, which was a very popular camera in it's day, had really poor sound quality and recalled them under a warranty fix but I tested and measured several "fixed" cameras and they still sounded horrible. That was the first and last time I have heard of Sony owning up to manufacturing a camera with really lousy sound.

All I can tell you is that I would complain to Sony really loudly and perhaps they will do something for you. The only reason they did with the PD-150 was because of grass roots mass complaining from thousands of PD-150 that all of the cameras had sound so bad that the cameras were basically only usable as a film camera, meaning you had to use double system sound.

This is all ancient history now as people have forgotten mostly about the whole Sony making lousy sounding prosumer cameras debacle but I do recall because I was involved in the whole thing. For some reason, Sony, who used to be the premier electronics company, in about the year 1998, forgot how to engineer audio circuits. It is strange that the VX-1000, the first Sony MiniDV camcorder that many of us owned and used alongside our $70,000.00 Betacams, had excellent sound quality and only used 32kHz sample rate even. But after the VX-1000, the preceding models all had terrible sound quality. This is one of the main factors I switched to Panasonic camcorders when the DVX-100 came out. Not so much for the 24P, more so for the high quality sound circuitry. All of this poor sound quality debacle is outlined in this article I wrote back in 2002. http://www.kenstone.net/fcp_homepage...ion_sound.html
Page down about 2/3 of the way through the article and you can see my comments on how I hoped that the soon to be introduced VX-100 would have good sound quality and you can see my report card grades for all of the previous Sony models.

I hope that you can get this resolved. Do you have access to another of the same model (have a friend/client with the same one?) that you could compare yours to? I wonder if this issue is endemic to the model or if you just ended up with a bad copy?

All my best,

Dan

Craig Irving · January 14th, 2008, 11:33 AM

I just got back last night, so I haven't had a chance to review much of the footage yet.

I don't have another V1U, but I'm going do some testing w/ an FX7.

I'm not ready to put-down the V1U though. I've had some fantastic performance with it so far. I've had it for a year and this is the first I've noticed anything unusual. Though I am confident that if there is an issue with my camcorder that Sony would take care of it under warranty. I'm aware of previous concerns people had with the PD-150, and such, but so far I've been quite pleased with the audio quality on the V1U. This was just a peculiar experience that I thought I'd run by you guys before I had the opportunity to do more testing. Again, since audio experts here (who know way more than I do) don't consider that noise to be an issue nor have they reported anything similar, then we shouldn't get carried away with any assumptions. Especially considering my inexperience with analyzing audio.

All I know is that everything sounded crystal clear and free of noise when I was setting up interviews using an ME66 and an ECM77B when the camera was in in STBY mode, and then it only began when I switched into REC mode. It's possible the noise was exaggerated in my 7506s, so I'll have to try them on my monitors at home tonight.

January 7th, 2008, 10:48 AM	#17
Dan Keaton Inner Circle Join Date: Dec 2002 Location: Augusta Georgia Posts: 5,421	Craig, I tried listening to your clip. I do not have all of my tools available here at my office. Also, my office has normal "Office Noise" making it less than perfect. However, I could not hear any significant noise. Could you check your file by downloading it yourself. Then please let me know if you hear the noise. __________________ Dan Keaton Augusta Georgia

January 7th, 2008, 04:39 PM	#22
Glenn Davidson Major Player Join Date: Dec 2005 Location: Nevada City, California Posts: 499	The clip does have a good sample of the noise, it is just very low level. I imported it into ProTools and raised the gain. Sounds like internally generated camera noise. It consists of a low frequency rhythmic motor boating and a high frequency whine. Can't you get decent Signal/Noise ratio by feeding a good audio signal? Last edited by Glenn Davidson; January 7th, 2008 at 05:38 PM.

January 12th, 2008, 08:00 AM	#27
Dan Keaton Inner Circle Join Date: Dec 2002 Location: Augusta Georgia Posts: 5,421	Dear Craig, How did your shoot go? __________________ Dan Keaton Augusta Georgia

January 7th, 2008, 10:36 AM	#16
Craig Irving Major Player Join Date: Jun 2006 Location: Toronto Posts: 539	http://www.badongo.com/file/7205625 Thanks for your interest everyone. Here's a wav that shows what I'm getting.

January 7th, 2008, 11:44 AM	#18
Steve Oakley Trustee Join Date: Apr 2006 Location: United States Posts: 1,158	I Dl'd your clip but it was silent.... sounds line a power supply problem in the camera. its not physically generated noise... unless the mic pre amp board is literally microphonic from the vibration of the motors running, but that would really be a long shot, although possible with a defective component. sounds far more like the camera's power supply is borderline and when the motors kick in for the tape transport, they start making dirty power because they are on the edge. its also possible that the motors themselves are putting noise into the camera's power, but very very unlikely. sounds like its time to send it in for service.

January 7th, 2008, 02:37 PM	#19
Daniel Epstein Trustee Join Date: Jan 2006 Location: New York, NY Posts: 1,267	Haven't listened to the clip but your description sounds like the tape transport is creating some electrical noise which is getting into the audio circuitry before it goes to record. I would bring this up with your dealer and the manufacturer directly as it might just be your unit but it also could be a problem with the whole series of cameras. Also you should record it to tape with out the Harddrive unit connected to make sure it is just coming from the Tape drive

January 7th, 2008, 03:41 PM	#20
Jeffery Magat Regular Crew Join Date: Feb 2007 Location: Toronto, ON Posts: 186	There is nothing on that WAV file you uploaded. Not even a single waveform. We'll need something where you're actually recording audio to see what kind of noise you're getting. Perhaps a snippet of that recording you made on your last shoot?

January 7th, 2008, 04:25 PM	#21
Jimmy Tuffrey Major Player Join Date: Jul 2007 Location: Bristol U.K. Posts: 244	I came across this same problem back in June. That was what brought me to this forum. The noise is there when you record. Also it has a very noisy cheap sounding headphone out. The gain knobs are best left at their centre dent 5 setting too if you want to avoid noise, bit pointless having them. My final verdict was that the sound of this model camera is poor to worse. Would be interested in what conclusions you come to. Particularly turning off the lcd. Why Sony can't sort the audio out on their cameras I don't know. Just used the new DSR 450 and the headphone out has noise and latency. One of three units sounded considerably less bad as well. The phono/line outs are said to be good though as is the recording apparently. Just a crap headphone amp circuit. Keep us posted on your test results. I was not the pwner and only had limited time to test the model I was using. Recorded double system audio in the end.

January 7th, 2008, 05:16 PM	#23
Craig Irving Major Player Join Date: Jun 2006 Location: Toronto Posts: 539	Hey guys. I re-downloaded that clip from the link I sent I sent you and I'm kinda surprised only a couple of you heard it. You actually shouldn't really need to touch the gain, I was playing back the clip in VLC Player and just boosted the headphone volume and heard it right away, it's constant. Also using the speakers of my laptop (though they're poor quality) it was obvious to me. It's not really that low-level to me, it's actually quite loud I feel w/ the interview subjects talking. I opened it in Sound Forge myself to look at it, and immediately I didn't see waveforms either, then I zoomed in quite a bit and did notice a pattern of dots (I really don't know much about spectrum/frequency analysis though) Here's a picture I posted of how it looks to me in Sound Forge 9.

January 7th, 2008, 05:29 PM	#24
Glenn Davidson Major Player Join Date: Dec 2005 Location: Nevada City, California Posts: 499	it is -58 db referenced to digital 0. That's pretty low.

January 7th, 2008, 05:36 PM	#25
Craig Irving Major Player Join Date: Jun 2006 Location: Toronto Posts: 539	http://i75.photobucket.com/albums/i3...seAnalysis.jpg

January 7th, 2008, 06:03 PM	#26
Craig Irving Major Player Join Date: Jun 2006 Location: Toronto Posts: 539	Hmmm. Alright so I guess my inexperience with audio is starting to show. It seems the consensus is that -58db is a very low level signal, and though I'm hearing a noise in my headphones it sounds like it's to be expected. Although it's confusing that it doesn't sound that low to me in my headphones. I guess I just expected absolute silence, since I can record a clip directly to HDD that doesn't have this silence (though I haven't yet examined it in Sound Forge, I'm still curious to know if it's -58 or something different). I'm going to be taking all your tips. I have been keeping my gain at around 6-7 (no higher usually). I'll try reducing it even more if I can. Thanks again everyone for your help, I appreciate you taking the time to download the clip and help me out on this. I really didn't want it to come across as "this is a serious problem" but more along the lines of "this is what I am hearing and should I worry about it" kind of thing. So I'm glad to hear it's normal.

January 14th, 2008, 11:33 AM	#29
Craig Irving Major Player Join Date: Jun 2006 Location: Toronto Posts: 539	I just got back last night, so I haven't had a chance to review much of the footage yet. I don't have another V1U, but I'm going do some testing w/ an FX7. I'm not ready to put-down the V1U though. I've had some fantastic performance with it so far. I've had it for a year and this is the first I've noticed anything unusual. Though I am confident that if there is an issue with my camcorder that Sony would take care of it under warranty. I'm aware of previous concerns people had with the PD-150, and such, but so far I've been quite pleased with the audio quality on the V1U. This was just a peculiar experience that I thought I'd run by you guys before I had the opportunity to do more testing. Again, since audio experts here (who know way more than I do) don't consider that noise to be an issue nor have they reported anything similar, then we shouldn't get carried away with any assumptions. Especially considering my inexperience with analyzing audio. All I know is that everything sounded crystal clear and free of noise when I was setting up interviews using an ME66 and an ECM77B when the camera was in in STBY mode, and then it only began when I switched into REC mode. It's possible the noise was exaggerated in my 7506s, so I'll have to try them on my monitors at home tonight.