Topic: Sony PCM M-10 with external mics noise floor question

[pool]

The M10 is incredibly quite when recording with internal mics.
http://www.avisoft.com/recordertests.htm
I had R09 and MT and they had the Niagara wall of hiss in the back when recording quite music. My aim in fact is to have very stealth gear for quite small ensemble music. N.B.1: observations like getting a Sonasax or Neumanns are therefore not fitting :-).
With the M10 using the internal mics hiss is not an issue. I bought it specifically for quite music. Literally, using the internal mics, noise is not an issue with the M10. In addition it picks up quite music (even ambient recordings) very well with mic sens LOW setting at level knob at 4!! So it's sensitive AND quite. N.B 2: observations about stereo separation are not the issue being discussed here, even though I do not find "stereo" separation in field audience recordings always desirable in the first place. For me stereo remains recording separate things left and right not field recordings...
Sample for M10 internal mics recording level 5 (let's say these are the quite passages between music): http://www.megaupload.com/?d=OJPPIW9M

The noise performance drops, when it comes to attaching EXTERNAL mics MIC-IN. I still can't understand how using DSM6/L (admittedly for rock music and which I don't own anymore) or OKM I (which I own and are intended specifically for classical /low volume music: copy/paste...Frequency range 30 Hz to 20 kHz, Noise floor Reference 1 Pa about 58db, Equivalent Noise Ratio
approximately 36 db, Border Sound 95 dB () without A3 104 dB () with A3) going mic-in, increases the hiss considerably as compared to using the M10's internal mics.
Sample for M10 rec level 5 with OKMI mic-in : http://www.megaupload.com/?d=GGLRM5ZK
When adding the AC3 with the OKMI using mic-in the hiss increases slightly further! (something to this effect is mentioned on the OKM site). N.B. 3 Kindly don't ask "how are you measuring the noise?". It's simple -record the same source in the same room with same recording level using the internal then external mics ....and you listen to the quite passage(the M10 internal mics are OKM have similar sensitivity - in fact note that in the audio samples attached, for M10 internal and OKM both pick up the low pigeon noise/cooing one storey up inside a loft on the roof).

Going LINE-IN using the OKM I + AC3 is VERY significantly lower than using internal mics. The AC3 acts a s a small preamp. But, if the music being recorded is quite, the signal could register low using LINE-IN input and normalizing *could* practically equal the same noise that mic-in would have, but I have to test this with both very quite music and normalizing.

(1) Is it the noise of the EXTERNAL mics being used (eg the OKM's) that is  causing the hiss or is it the M-10's internal pre-amp causing this hiss?

(2) If it's the internal pre-amp, shouldn't it also cause hiss when using the M10's internal mics?

(3) Is there so little hiss when using the internal mics because the internal mics are so quite themselves? If so, then I'm ready to have the M10 opened up and have its mics "extended"! If same noise performance with the additional advantage of having them extended to reduce handling noise (I dont find "stereo" separation in audience recordings desirable most of the times) is got, I will have it done!! :-) No need for other preamp or mics. Something similar has been done on the R-09 but these would be "external" :-)

[Ozpeter]

The site you link to provides measurements of the mic inputs, not the performance of internal mics.   As stated in another thread, this shows the M10 mic inputs are very satisfactory.

[MikeMannZ]

The site you link to provides measurements of the mic inputs, not the performance of internal mics.   As stated in another thread, this shows the M10 mic inputs are very satisfactory.

I believe that chart shows levels for the internals of the M10.  If you look further down the chart you'll see other recorders that are noted when a different input is being measured, like the dr-1.  I will admit that's a lot of hiss for recording in quiet situations.

[pool]

The site you link to provides measurements of the mic inputs, not the performance of internal mics.   As stated in another thread, this shows the M10 mic inputs are very satisfactory.

I I will admit that's a lot of hiss for recording in quiet situations.

Are you referring to recording with internals?? Because I can assure you using internals IS quite! Pls see samples I attached. I am not knowledgable if it is the preamp or the mics themselves (hence my post) but I think thats pretty quite. It is very sensitive so you dont actually have to turn up the dial up. As I mentioned, I can catch pigeons on the roof even if all windows are closed!!

[MikeMannZ]

Are you referring to recording with internals?? Because I can assure you using internals IS quite! Pls see samples I attached. I am not knowledgable if it is the preamp or the mics themselves (hence my post) but I think thats pretty quite. It is very sensitive so you dont actually have to turn up the dial up. As I mentioned, I can catch pigeons on the roof even if all windows are closed!!

Sorry I was speaking about your tests with the mic and line ins.

[chrise]

I believe that chart shows levels for the internals of the M10.

The Avisoft Recorder Tests:

http://www.avisoft.com/recordertests.htm

provide measurements of the microphone input noise levels.  That's why the page is entitled "Microphone Input Noise Comparision".

There are recorders listed that don't have internal mics.  The dr-1 has 2 mic inputs (1/4 and 1/8) and they are tested separately.

[MikeMannZ]

There are recorders listed that don't have internal mics.  The dr-1 has 2 mic inputs (1/4 and 1/8) and they are tested separately.

My bad....only one cup of coffee so far...brain still sleeping...

[MikeMannZ]

The site you link to provides measurements of the mic inputs, not the performance of internal mics.   As stated in another thread, this shows the M10 mic inputs are very satisfactory.

I think measured results are only that.  What one interprets to be acceptable or not is really the deciding factor before a purchase.  I personally think the level of noise I hear in pools samples may be a bit too much for recording lower level classical and jazz situations. 

[chrise]

I wonder if Pool had some other problem.

Perhaps his mic(s) are not as suitable for quiet stuff as he hoped ?  Perhaps his mic is faulty ? Perhaps his M10 is  faulty ?

Or some other problem.

[ghellquist]

My guess is that the culprit is the OKM mics. Small mic membranes typically has a higher hiss (noise) level than larger ones. And a manufacturer that does not publish noise floor level in the same way as other manufacturers probably is not very proud of that specific part of the product.
 
You can most definitely better that by going with mics like the DPA4060 (which is a few dB better than the 4061 often seen around here). If you want to go even better you are up att mics like the Sennheiser MKH8020.

// Gunnar

[pool]

My guess is that the culprit is the OKM mics. Small mic membranes typically has a higher hiss (noise) level than larger ones. And a manufacturer that does not publish noise floor level in the same way as other manufacturers probably is not very proud of that specific part of the product.

// Gunnar

ghellquist
They do publish them. I didn't copy all the data, now corrected:

Frequency range 30 Hz to 20 kHz, Noise floor Reference 1 Pa about 58db, Equivalent Noise Ratio
approximately 36 db, Border Sound 95 dB () without A3 104 dB () with A3

[MikeMannZ]

My guess is that the culprit is the OKM mics. Small mic membranes typically has a higher hiss (noise) level than larger ones. And a manufacturer that does not publish noise floor level in the same way as other manufacturers probably is not very proud of that specific part of the product.
 
You can most definitely better that by going with mics like the DPA4060 (which is a few dB better than the 4061 often seen around here). If you want to go even better you are up att mics like the Sennheiser MKH8020.

// Gunnar

wow!  If I have to plug a 500 to 1000 dollar mic into my M10 so that I don't get any hiss then I guess I'm staying with the on board mics.  I bought this thing to record rehearsals and maybe the occasional show, but if it requires 3 grand worth of gear I'd rather spend that on my drums or on mics for my studio.

[Ozpeter]

I've done some simple noise comparison recordings using a inexpensive Naiant omni mic, M10 mic input vs R-44 mic input vs M10 internals, and as soon as I have a moment I'll post the samples.  The Naiant has the advantage for such a test of being able to run on phantom (R-44) or plugin power (M10).  I know from other tests that the R-44 mic inputs are fine with expensive Sennheiser low noise mics, so it will be interesting to see whether there's a significant difference with the M10 inputs.  Watch this space...

[Ozpeter]

Here's a link to my sample -

http://www.fileden.com/files/2007/9/22/1451533/M10%20noise.wav


It's 44.1/16 mono, about 14MB

It's a clock tick test, whereby the mics are placed very close to a small electric alarm clock, which helps to get the relative levels aligned without masking noise.  Levels have been raised by over 20dB in order to help in hearing the noise.  The ticking of the clock would normally be almost inaudible unless you put your ear very close to it.

The recording was made in a suburban house at night in a bedroom with the door closed.  To get a perspective on the noise vs the actual sounds you hear, at about 2'08" you can hear a rat scamper across the ceiling, and from about 2'19" you hear my tummy rumbling several times, about three feet from the mics...

First you hear the Naiant mics into the Edirol R-44.

Then at about 1'03" you hear the same mics (not moved) into the M10.

Then at 1'54" you hear the M10's internal mics, placed the same distance from the clock as the Naiants had been.

I tried to get the levels ballpark the same during the recording but some adjustments were necessary afterwards.  What I tried to do was to ensure the level of the clock tick was subjectively the same through the three recordings.

To me, the Naiant > M10 recording is slightly lower noise than the  Naiant > M10  recording.  I don't find that surprising.  However, for all I know the Naiant mics' self noise may reduce when on phantom power (R-44) vs Plugin Power (M10).  But I think it's safe to say the M10 mic input is no more noisy than you'd expect at its price point.

The M10 internal mics sound noticeably quieter.  However, by ear and (looking at analysis displays in Adobe Audition) the M10 recording has less HF content and more LF content, and this would tend to reduce the perception of noise in the recording.  Subjectively the Naiant mics produce a recording more like my experience in the room at the time.  You don't hear that rumble naturally - the nearest major road is at least five minutes' walk away.   

I'd say that if I were recording classical music with the M10's internals or the Naiant mics into the M10 mic socket, noise from the audience and so forth would be more significant than noise from recording process, when replayed at natural levels.  And noise from the room you were replaying the recording in would also be more of a problem. 

When replaying nature recordings, if you wanted to reproduce the natural sound at a natural level then again, there would be no problem in my view.  If you wanted to reproduce faint sounds at a much higher level than in real life, well, you'd hear some system noise, but to avoid that problem you'd be paying big money for both mics and recorder.

[xpander]

To me, the Naiant > M10 recording is slightly lower noise than the  Naiant > M10  recording.  I don't find that surprising. 

I do, for me they're just about the same. I wonder about the Edirol though, have to check the sample. 

Anyway, nice test, thanks!