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Old May 29th, 2009, 05:58 AM   #1
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Excessive PCM-D50 noise level?

I would like an opinion as to whether the noise level of my Sony PCM- D50 is excessive. If I am in a very quiet environment I can hear through my headphones a build up of noise level as I increase the gain. The noise I hear is also recorded. It starts when the gain reaches 4 on the control knob. At 5 the noise is quite obvious. At 6 it starts to register on the meter i.e. around minus 46 db (the meter's lowest reading is minus 48 db). At the maximum level of 10 the meter reads minus 26 db.

I have tried the various record modes, the low cut filter, a memory stick as well as the built-in memory and the noise pattern is the same. The noise sounds a bit like rain. I have only used the built-in microphone and there is no handling or wind noise during the tests.
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Old May 29th, 2009, 08:07 AM   #2
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Mine sounds fine. Everything I've read and experienced myself says that the internal preamps are excelent quality so you should be picking up ambient room noise, but nothing that sounds like rain.

Are you sure you don't have the -20dB switch on? At max gain you should be peaking higher than -26dB, even recording ambient noise. If you have the 20dB pad on that might make a difference.
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Old May 29th, 2009, 08:38 AM   #3
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Mine's fine too. I'd say you've got the record gain and headphones turned way too loud.
Try recording and listening real world levels.

Cheers.
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Old May 29th, 2009, 08:42 AM   #4
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Alastair:

While I have not done your test, and the ambient room tone would of course have a major effect on every different test, I have never had any noticeable pre-amp or other noise from my PCM-D50.

The PCM-D50 built in mics are very sensitive to sound and also the slightest air movement. In fact, almost any air movement will make noise.

So to test for inherent noise in your unit, like the preamp, plug in a mini connector to the microphone input with no microphone attached. That will shut off the built-in mics to take actual sound out of the evaluation. I dont have my D50 in hand, but a better way might be to flip the switch from mic to line input, but I cant remember if that changes the level or changes to the input on the side named line-in.

My D50 has been absolutely excellent quality. Test yours some more, if you really have noise, I would send it back/have it repaired
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Old May 29th, 2009, 09:06 AM   #5
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Thanks Stan,

The -20 db switch when set to on reduces the meter reading by 20 db which is what I would expect.
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Old May 29th, 2009, 09:15 AM   #6
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Thanks Allan,

My real world is recording wild life sounds. The calls are relatively weak at least there are by the time they get to me. Even under very calm conditions on a very quiet night I cannot use the gain set higher than 4 without the noise spoiling the recording on this particular device. The problem occurs with all my headphones.
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Old May 29th, 2009, 09:45 AM   #7
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Thanks Jeff,

I am becoming hopeful that the problem is with my recorder only. I am aware of its sensitivity to air currents and there was no air movement for the tests which I did at 3 a.m. on a foggy night. There was no traffic noise, no fridges, no transformers just an occasional distant click or clunk that showed on the meter. I even held my breath.

I have just tried your tests, cutting off the internal microphones with a plug in the external microphone socket reduces the left hand meter reading and eliminates the right hand meter reading. We may be getting somewhere at last!

Switching the microphone/line switch to line eliminates the meter reading even on full gain.

Do I have a suspect microphone amplifier for one channel?
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Old July 20th, 2009, 05:29 PM   #8
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Alastair

I have exact the same problem with my PCM-D50 (1 week old).
Noise starting at 4 (heard through the headphones).
I've tried external mics but the results were the same.

Local Sony support wasn't very helpful, I couldn't get a straight answer.
I wonder how it ended for you. Is it normal and it's us expecting too much?

Cheers
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Old July 20th, 2009, 08:04 PM   #9
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Mine is working fine... I have had mine since they came out...
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Old July 21st, 2009, 07:24 AM   #10
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Andrzej

My problems continue. The recorder has been to Sony in Sydney where it was examined by a Sony engineer. His examination seemed to just involve comparing it with another. When I asked whether he had done the user type test I described I did not receive an answer. He suggested the noise was produced by the environment. If that is true one should be able get an idea of the direction of this "environmental noise" by pointing the microphones in different directions to see whether the noise gets louder or softer. When I try redirecting the microphones it makes no difference to the volume I hear.

My PCM-D50 has been returned with the suggestion that I should try a more sensitive external microphone. I have tried a Senheiser M66E and K6 module which seems to be more sensitive than the built-in microphones. As you have found the same problem is present.

As I see it my and now your PCM-D50 is quite useless at a gain setting above 4 and a bit. In the last few days I have been trying to to record the the calls of the Australian Superb Lyrebird and a gliding arboreal mammal - the Yellow-bellied Glider. Both species have very loud calls and I was able to get reasonably close and I had calm conditions. I say recording conditions are good when I can hear the occasional truck from a distance of 6 km. I used a gain setting of 5, the "noise" was present and starting to mask the calls I was trying to record. At higher gains the masking was more severe so 5 was as high as I was prepared to go. Playback through the headphones was tolerable but when the calls were transferred to my MacBook Pro the levels were very low even at full volume. I need to to be able to use more gain.

The PCM-D50 is advertised as being suitable for recording "nature" which is a very demanding task. The PCM-D50 has a lot of great features but regrettably recording quality is not one of them. Over the years I have had three Sony tape recorders and two Nagras. I expect a bit more internal noise at the highest gain but the noise I am getting from the PCM-D50 is unacceptable at anything over 4 out of the 10.

I would like to know if those who are happy with their PCM-D50's use them at gains higher than 4, and if so, are they happy with the results?
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Old July 21st, 2009, 08:38 AM   #11
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Alastair:

For recording using the built in mics on my PCM-D50 I am generally right at 4 due to the nature of what I am recording and the limitations of the microphones/self noise.

When I use the D50 to capture the signal off my wireless reciever I can run at 5 or 6 with no problem.

If you see no noise with the recorder on mic and a mic plugged in but not turned on, your pre-amps are fine. With the recorder on line in, you bypass the pre amps.

I think you are just seeing the S/N ratio and self noise limitation of the built in microphones. You need a a high end 80+db S/N ratio mic and still be pretty close to the sound. There is another thread related to mics in this use on the forum.

Generally, I think your expectations vs. the technical and physics aspects of audio equipment may not be meshed yet.

It would be great to hear examples of your audio so the expects could provide an opinion.
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Old July 21st, 2009, 10:04 AM   #12
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IMHO, the PCM-D50 preamps are excellent for a portable device and sound great, but they are noisey. My guess is there just isn't enough power coming from the batteries. I never push mine past 6. I record forest ambiance this way often.

I recently tried to record a voice over using a PCM-D50 and a Rode NT2 and in order to get a decent level I had to push the gain past 6. The noise was pretty bad and I had to run everything through noise reduction before it was usable.

All in all though, I doubt a better portable recorder exists near the PCM-D50's price range.
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Old July 22nd, 2009, 08:16 AM   #13
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Quote:
Originally Posted by Jeff Kellam View Post
Alastair:
If you see no noise with the recorder on mic and a mic plugged in but not turned on, your pre-amps are fine. With the recorder on line in, you bypass the pre amps.

Generally, I think your expectations vs. the technical and physics aspects of audio equipment may not be meshed yet.

It would be great to hear examples of your audio so the expects could provide an opinion.
Hi Jeff,

Thanks for the comments. I am not sure that I know how to post a recording but I will try over the the next few days. Yes, I may be expecting too much of this device but if I was marketing a recorder I certainly would not market one where over half the gain range is unuseable. Instead I would omit the 5-10 settings.

I have the recorder set to mic at the moment with a Senheiser K6 module and M66E mic connected via a mono plug. The recorder is turned on and the switch on the K6 module is set to off. If I now increase the gain I see nothing until just pass 6 when the meter shows a reading of -48dB ( the minimum reading it registers). If I continue increasing the gain to 10 the meter reading becomes -30dB. When I play back this "recording" I hear "the noise" in fact I hear it at gain 5 when my headphones setting is 5 and I hear it at gain 4.5 when my headphone setting is on 10. If I repeat the experiment when I am ~ 30 meters from an AC supply I get the same result.

I would appreciate any further comments.
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Old July 22nd, 2009, 09:18 AM   #14
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I made some screenshots of frequency spectrum at different gain settings
but I can't post it (not allowed?).

Take a look at:
Avisoft Bioacoustics - Microphone Input Noise Comparision

I downloaded some of those recordings so I could compare the spectra.
My impression is that compared with them (original not normalized)
Sony has much more noise, especially <1kHz.
My recording was made in a quiet room, at night, "ambient" noise was about 40 dB (measured with dB meter).
So I guess we have to live with it or change the gear.

"The PCM-D50 is advertised as being suitable for recording "nature".
Well, take a closer look at the picture in the Operating Instructions (page10).
I didn't know that in Sony's world even birds have right to be famous for
15 minutes (gain set at 4).

Last edited by Andrzej Duda; July 22nd, 2009 at 05:12 PM.
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Old July 22nd, 2009, 03:22 PM   #15
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Alastair -

What kind of windscreen are you using? For any outdoor recording, you MUST use a windscreen w/ the PCM-D50.

Have you tested it indoors, in a closet where there would be no wind movement?

I use it outdoors w/ a homemade ripstop nylon windscreen, at volume setting 6, and have no problems. Without the windscreen, all I get is wind noise.
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