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.

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.

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.

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

Thanks Stan,

The -20 db switch when set to on reduces the meter reading by 20 db which is what I would expect.

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.

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?

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

Mine is working fine... I have had mine since they came out...

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?

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.

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.

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.

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).

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.

Alistair, IMO it's apparent you're not getting a loud enough signal into the D50 to get above its residual noise.

If you really want to get clean nature sounds on the D50 from where you locate, I'd put a JuicedLink C231 mixer in front of the D50. I've just got one and it's very quiet, and I'm pretty sure I can boost the signal into the D50 above its noise, I'm checking it out.

But for nature recordings, what I used to do was plant a Sony HI-MD Minidisc as close as I could get to the area where the sounds would originate.

This was many years ago when the HI-MDs first came out and I used the Audio Technica AT822 mic. After some experience, I could set the correct level which was well above the equipments noise level and I got a good clean 90 minutes continuous. HI-MDs now are very cheap on Ebay.

Cheers.

Thanks Jeff for contacting me privately. I will check your references ASAP.

It is a pity your post was not accepted. Several times I have prepared a post only to have it disappear when I press the “submit” button. I understand your frustration. I find that the longer I take to prepare the post the more likely it is to disappear. My workaround is to prepare my post in Word and then copy and paste to DVInfonet, sometimes I have to do this more than once before it is accepted.

At a gain setting of 6 on mine the ambient sounds are "drowned out"

I am pleased to report a sudden and inexplicable improvement in the recordings produced by my PCM-D50. Without knowingly changing anything I can now record at gain settings above 4 without introducing undue noise.

In a quiet enough environment I can use the full gain setting of 10 using either the inbuilt mics or a Senheiser K6/ME66. My only guess as to the reason behind this improvement is that there may have been a dirty contact somewhere that has cleaned itself with use.

I would like to thank everyone for their comments and suggestions.

Thanks to all
Alastair Traill

Alistair

Are you sure it is not the -20dB switch?

[Recording the sound of a palm slapping forehead]

Andrzej and Tsu,

I am quite sure it is not the -20dB switch. I know this switch works but as yet I have had no occasion to use it, my problem has always been to get enough signal. I only hope that this improvement whatever its cause is long-lasting.

Andrzej, do your PCM-D50 problems persist?

pcm d50 noise problem
 

Dear Alastair,
I very happy finding your post on this forum, after some hours of search.

3 weeks ago I bought a sony pcm d50 and I have exactly the same problem.
A noise appears around 4/5 gain level, that is very very uncomfortable and, i think, this is not normal. My pcm d50 is useless if I use a gain above 5.


One question : did you tried to connect the sennheiser k6/me66 on the "line in" connection ? Or did you only connected it on the mic connection ? In the case this noise come from the preamp, the line in connection would ignore the pcm d50's preamp, and logically ignore the noise...


Any suggestions or help to fix this problem would be very appreciated.


(sorry for my bad english ! and best wishes from france)


clément

Dear Clement,

Sorry to hear that you are having the same problem as Andrzej and myself. It spoils what is otherwise a great little recorder. I would be interested to hear what sort of response you get from Sony. Neither Andrzej or myself were impressed with the responses we got.

In answer to your question I only connected the external mic to the mic input.
In a day or two I intend to post further details of the improvement I reported on the 24th of July.
Andrzej sent me a sound spectrograph of the sound from his PCM-D50. I am hoping he will post it soon.

I do not own a PCM-D50, but on other systems, I have encountered noise coming from the "plug-in power" on the 3.5mm mic input, when using self-powered mics. ie: battery. On these systems, usually a capacitor needs to be soldered into the mic connector to shunt the plug-in power to ground.

On Zoom H series recorders, plug-in power can be switched on/off via the software menu. (one thing Zoom did right) On many other portable recorders and many body-pack transmitters I've encountered, it cannot. I am not privy to the D50's internal workings', so this is just a consideration. Cheers, Rick

(do not confuse "plug-in power" (bias power) with "Phantom power")

Dear Alastair and Rick,
Thank you for your responses

The sennheiser k6/me66 has is own preamp, after reading some articles on it, I really think it must be plugged into the "line in" connection. (Not the mic connection)
I would like to know if it will be a solution for me to use an external microphone with external preamp/phantom power (like the sennheiser k6/me66) to bypass my "useless" intenal pcm d50 preamp.

I have made a small record for you to get an idea of my problem. The link is : http://dl.free.fr/fdJ5iWTVm

(you have to follow the link and click on "telecharger ce fichier" to download the file. MP3 320 kbps/16 bits/44100 mgz format)

This is a record made with my pcm d50 with internal microphones, in a total silence room. The rec level gain is "6,5". As you will hear there is many noise, even in a silence room...

All condensor mics, such as the ME66/K6, have their own built-in preamp but those are NOT preamps that raise the signal to line level. The mic output is still mic level - the ME66 is a fairly hot mic, true, but it doesn't even come close to sending a line level output signal from its preamp stage. If you want to use a prosumer or professional mic in order to bypass the mic input preamps on the D50, you'll also need to get an actual preamp such as found in a mixer that takes the mic up to true line levels, nominally -10dBv on consumer gear. But a note of caution ... it might not actually be possible to bypass the preamps even by using the line-input. I can't locate a schematic so there's no way to know for sure about the D50, but to save money some consumer gear designers will simply pad down the line input to mic level and send it on through the mic preamps, same as signals from the mic level input.

Is the noise you're referring to in your recording the continuous sort of crackley hiss that runs through it? I also hear some traffic noises (?) and other faint distant rumblings coming in sort of low and faint and what might be some breath sounds and motion in the room.

Recently I could compare recordings of "silence" made by Alastair and me.
The recordings were made in a quiet room, gain was set at 10.
My impression is that there is no significant difference between
the two recorders (at least when gain is set at 10).
SonyInGain10.jpg = spectrum of my Sony.

I've tried something else.
I connected 2 K3 Sennheiser mics through the external mic input.
Gain at 10, highpass filter was on, 24 bits, 44.1 kHz. And the "silence" was recorded.

Senn 10 On.jpg = the spectrum when the Sennheisers were on.
So it's the noise of the amps + mics + silence.

Senn 10 Off.jpg = the mics were still connected but off (no signal from the mics).
It's the noise of amps only.
The spikes at 50Hz, 150Hz and 250Hz are strange since the recorder is powered with batteries.

As you can see the amps seem to be OK, noise less than -105dB.

So, what does it mean?
The silence was not that silent (I doubt it) or
the mics, both Sennheiser and Sony, are too noisy (that's what I think) or ...

I'm afraid we are at the beginning.

Re: Excessive PCM-D50 noise level?
 

Sorry to revive this old thread but I'm having exactly the same issue described above. I'm a photographer doing a little bit of video. I thought I would learn the basics of sound recording and I happened to have a Sony PCM-D50 purchased for a project a few years ago. But when I use the built-in mics I hear rather pronounced noise. I don't recall this being the case when I initially purchased the unit.

I'm getting basically the same result as the OP--noise starts around a gain of 4, at 6 I'm at -40db. Sounds like rain, as he described. I've checked the attenuator, checked all the settings. Everything seems as it should be.

Two notes/possible clues:

1) When I first tried the unit yesterday the noise was far worse than I described above. It was crazy. While wearing headphones I was playing with the angle of the microphones, clicking them back and forth and the noise suddenly lessened to the numbers described above.

2) For reasons that are unclear my db scale is different than that of the OP's. My scale run -50 -40 -24 -12 (highlighted) -6 0

3) I tried plugging in a cord to the line-in port and changed the mic/line-in setting to line, as described earlier in this thread. Just a cord, no mic. I then wheeled through the gain, hearing only the faintest bit of noise through the higher end of the range, finally near 10 hearing a faint but noticeable level of noise. If this is really the pre-amp noise and how it is supposed to be then I am very impressed.

So, is my unit working correctly or is the built-in mic noise (at the "improved" level) abnormal? I'm a novice at this and have little to compare it to.

A second question, if the contacts or wiring of the mics is an issue has anyone disassembled their unit? Something doable? There are two screws which appear to be holding the mics in place. They are tempting me despite my lack of knowledge of electronics!

All advice welcome,

--Darin

Re: Excessive PCM-D50 noise level?
 

Testing with an unterminated line input is not an accurate test, as is the internal mics with ambient noise present (despite the ambient noise which you may hear as silent.. is not) The only accurate mic test would to dissemble, remove the mics and terminate the input to the proper resistance and reference test parameters (whatever they are).

Re: Excessive PCM-D50 noise level?
 

The 'noise' discussed in this thread is often described as being variable. An early post also mentions recording on a 'foggy' night. I wonder if any of these problems are moisture related?

The paper from Sennheiser here: http://en-de.sennheiser.com/download...tePaper_en.pdf explains the rationale behind their RF condenser mics. The paragraph at the top of page 3 about humidity is quite interesting.
Certainly, I have encountered problems in the past - on occasion - with variable noise from electret capsules, where those capsules have been subject to outdoor weather conditions.

Not, I have to say, with the recorder specifically mentioned in this thread, but it may be a similar cause?

Clearly, Sennheiser wouldn't have gone to the trouble of developing RF condenser microphones if there was no need....

.. Just a thought....

Re: Excessive PCM-D50 noise level?
 

Update:

@Rick I tried the unit using a Rode VideoMic. I have an older unit and a newer one. In both cases the background hiss was barely audible, even at higher gains. Unfortunately in both cases the signal was weak as well. Even at the highest gain levels, speaking directly into the mic with my mouth brushing the deadcat the meters didn't go above -24. I'm a novice on this but shouldn't this mic work properly with this unit?--I routinely use this same mic with my camcorder with no issues.

@Roger I *do* live in a foggy area but the unit has never, in my recollection, been wet with dew and has spent most of its life in its box on my office shelf.

I also noticed that the attenuator switch (which isn't as tight as the mic/line switch) works for the built-in mics but doesn't seem to do anything with the external mic. Not sure if this is normal behavior. The manual does not say anything about it.

If no one else has a D50 here I will try to call the Palo Alto Sony store to see if they have a D100 in stock and may drive down and compare the two directly.

Thanks,

--Darin

Re: Excessive PCM-D50 noise level?
 

I have the D50 and did the test with a cord only plugged into the line input. Headphones set at 10, going up on REC Level, 6 shows -50, 7 = -44, 8 = -32. With the 0 - 20 switch set to 20 position, the reading at level 8 changed from -32 to greater than -50 (off scale).

I have used my Zoom H4n and the D50 and I guess I never push them up so far as to get lots of noise. If I did, there's always Audiology for noise removal. I think for what I paid for these recorders, they work pretty good. Sound Devices are expensive for some reason, not just the name.

Mark

Re: Excessive PCM-D50 noise level?
 

Darin - I don't think that noise connected with AF condenser mics (which include electrets of course) and environmental conditions is a black and white 'wet weather yes or no' situation. There are lots of comments online about the potential problems with 'standard' AFcondenser mics and dirt and dust, as well as moisture.
This thread : Humidity's effect on condenser microphone (especially post #9) is typical.

In the case of the D50 noise, it should be simple enough to isolate a mic fault from a preamp one....

Connect an external mic and see if the noise level is noticeably different......

*Edit* - There are some sample noise level samples for the PCM D50 - along with several other units - on this page :
http://www.wingfieldaudio.com/portab...e.html#samples

Should give you an idea of what to expect....

Re: Excessive PCM-D50 noise level?
 

O.K., just swinging back around to follow up and add to the the great internet knowledge base.

Lacking any other real plan I ended up buying a mint condition unit (Sony PCM-D50) off of E-bay. So now I have something to compare mine to.

The units perform essentially identically.

The bottom line is that there is pronounced hiss with the internal mics starting at a gain of 4 and increasing until the mics are largely unusable at 6. Note that at arms length you'll be picking up your breathing at 6 and quiet whispers, barely audible to yourself, are clearly legible at that point. Probably no need to be at 6 in the first place.

However, with an external mic it is fairly quiet all the way up to 10. With a Rode Video Mic (new version) set at +20 it sounded very good and very quiet (although the recorder had to have the gain turned up all the way to 10 to have a voice three feet away reach -12 on the levels).

So for the non-sound guys like me (and many others who use the PCM-D50 or similar) the unit is fine: 1-4 for internal mics, all the way up to 10 with minimal noise with an external mic, depending on the mic, I'm sure (you'll barely hear the self-noise compared to the thunderstorm at 6 with the internal mics).

Now, about that MixPre-D I've been eyeing...

--Darin

Re: Excessive PCM-D50 noise level?
 

I bought a decent condition PCM D50 off of ebay. I had the same issue where there was excessive background noise. An email conversation with Sony support resulted in this remedy:

1. backup to your computer all the audio on the D50.
2. FORMAT all storage media

It seems that if there are a lot of small files on the D50, it can generate noise.

If you look at the D50 manual on page 49: http://www.avisoft.com/PCM-D50.pdf

"Noise is heard"

"Noise may occur if many small-sized files are recorded in the current memory. Save the tracks on the hard disk of your computer (page 36), and then format the memory (page 41)."

Re: Excessive PCM-D50 noise level?
 

Haven't read all the messages here, so sorry if I am repeating something. Try a fresh set of quality batteries.
My Sony works just fine. I also have the Zoom H6 which is also excellent.

Re: Excessive PCM-D50 noise level?
 

Hmmm. Never noticed much noise with mibe - I;ll dig it out after dinner and check. On the other hand I don't have many small files either - mostly long recordings.

Why on earth would a lot of files cause noise - this is more puzzling than the original problem!