Topic: Externalising the internal mics of the PCM-M10

[PeteJE]

Also desiring to extend the M10 mics with something comparable, I recently ordered Primo 172 microphones from frogloggers . . .
http://www.frogloggers.com/FORMgallery4.htm



(Though without microphones at the moment, the solder will be nice and hot within the hour, on another project.)

This is what I was going to suggest - these are the M10 capsules, I believe.  Buy several pairs and experiment.

[NOLAfishwater]

Many experts have chimed in and it is apparent that you only believe tearing your m10 apart is the way to go. So, I say go ahead and ruin your deck and send us all pics

[pool]

...are there mics with the SAME sensitivity (hence no use of additional pre-amp required) and noise as the m10 (call them cheap) ?

[pool]

mshilarious - thank you.  if using the frogglers/EM172 one builds external mics and uses the line or mic in jack would the result be more noise or less sensitive then the current internals of the M10? I dont know if the path of the internals, the mic-in and line-in jacks with the pre are the same.....??!!!!!

[landshark]

I use Chris Church's CAFS omnis with my PCM-M10, direct with no battery box.  I think the PCM-M10 mics are great, but I think the CAFS's are quieter, and sound like they have better dynamic range.  I'm sure part of the sound improvement is that I can better position the mics as compared to the fixed internals.

I would be shocked if cracking open the PCM-M10 and jury-rigging some microphone extension could in any way improve the sound of recordings as compared to the comparably simpler and less expensive alternative of buying some CAFS's (or Countryman B3's) and just plugging them in. 

[sunjan]

I think going mic-in using external mics would be noisier.

I think a dozen of tapers here will be able to prove you wrong.
Properly powered CAFS, Countryman B3, DPAs etc going mic-in would beat the internal mics of the M10, especially if you intend break them out DIY.

Did the OP download samples to compare?
There are a few here:
http://taperssection.com/index.php?topic=139109.0
http://www.archive.org/details/seven2010-07-13.seven2010-07-13.ca14.flac16
http://www.archive.org/details/matisyahu2010-09-20.flac

[illconditioned]

The venues are small ensambles were often one is a meter away from players, in churches and very small halls. If it summer and youre practically wearing nothing (even in a church :-) yes difficult to hide things. As i said ive tries OKM-II for classical and have tried other mics and pres. Plus, i want a low cost solution that is comparable to the internal mics of the M10.

It is understood therefore that the M10 uses 1 pre. If that is so does anyone know what is the noise and output (sensitivity?) of the M10's internal mics so that any external mics (like the AT853/DPA's) i might try are compared with it?  - thanks

I have cracked open the Sony PCM-M10.  It has 10mm omni microphones, two-wire connection, rated self-noise 18dBA.  These are quite good mics, especially for quiet recordings.  They are *excellent* for voice, but find the quality insufficient for (serious) music listening.  Also, they *may* overload a bit at loud levels, though I have not experienced this myself.

I would recommend you use external mics, but no battery box or preamp.  With careful selection, you can get very good performance.

What capsules to use?  If you can tolerate higher self noise (say 24dBA), I would get a pair of Countryman B3 lavalier mics.  Wire these directly to a miniplug and you will be astonished by the clarity and realism of these mics, both for ambient and music recording.  If you're worring about connectors, get a right-angle miniplug and tack it on with some hot melt glue, then cover with gaffers tape.  Start recording, set levels, lock unit, and gaffers tape over the level control and you can tolerate any stealth situation.

If you need lower than 24dBA, then you will *probably* need some more effort.  But to be honest, 24dBA is pretty quiet.  Even if there is a (slight) hiss, it is nothing when played back on a recording with full dynamic range.  You really only need to go lower for either nature recording, or (quiet) spoken voice recording.  Any "performance" venue, theatre or music, will have acoustics and/or sound reinforcement suitable for getting over this pretty low noise floor.

Now, that said, please do not tear the mics out of your M10.  These always serve useful in cases of impromptu or "point and shoot" recording where you don't have time to setup gear.

  Richard

[wmacky1]

Yes, no need to tear up the recorder when you can buy the internal caps (Primo 172's). Plugging them in the mic in, is no different than the internal convention.  That said, why are some here dogging the internal caps? The 172's have self noise comparable to the Rode NT4 used by the nature guys. On other forum they seem to be rated as the best internal mics available in any portable. These are the same caps as the expensive Telingas.

[illconditioned]

Yes, no need to tear up the recorder when you can buy the internal caps (Primo 172's). Plugging them in the mic in, is no different than the internal convention.  That said, why are some here dogging the internal caps? The 172's have self noise comparable to the Rode NT4 used by the nature guys. On other forum they seem to be rated as the best internal mics available in any portable. These are the same caps as the expensive Telingas.

Those Primo mics are great.  I've tried EM171 (10mm cardioid) and EM173 (10mm omni).  I've also tried EM158 (6mm omni).  Very low noise, but the sound itself is not perfect.

But , if I had a choice between Sennheiser KE4 (5mm, omni, 27dBA self noise) and Primo EM17x, I would choose the Sennheiser.  There is something ("warmth", "detail", "definition") that the Senns have that Primo is missing.  The only thing I can imagine is the diaphragm thickness/tension/material.  The Senns use a gold vaporized diaphragm, while Primo uses Ni/Cr plating (I believe).  It may also be the thickness.  The absolute best sounding mics are Geffel, DPA, etc "measurerment mics", that use 1 micron solid metal diaphragm (Nickel or Stainless steel).  By the way, Countryman B3 are stainless diaphragm.  One of the few lavalier mics that are.  Most others (eg., Sennheiser, Audio Technica, etc, are gold vaporized).

  Richard

[Ozpeter]

That said, why are some here dogging the internal caps?

I guess I'm the chief critic of the M10 internals here, but that's purely on the grounds of the poor stereo image.

What would be interesting would be if someone was brave or daft enough to attempt to replace them with the equivalent cardioid capsules, albeit into a case not designed for cardioids.  I'm not planning to...

[illconditioned]

I would guess it's the hole pattern in the case, those apertures cause the bumpy stuff in the Primo's HF response (as shown in their specs).  This is why I've shied away from the Primos; I don't want to be troubled with modding the cases to fix that.  Also, the primos spec as -10dB at 20kHz, whereas WM61As will be up at 20kHz . . . which is easy to correct with EQ; the Primo's peaks and nulls would require a lot of narrow bands to correct.

Obviously I have my biases . . .

I'm not sure it is the holes that cause the 'bumps'.  The holes are over an area of something like 1/4" diameter or less.  Many mics have an opening larger than that, even small capsules.  My *guess* is the holes are there to allow a fairly large opening that is both mechanically strong and inexpensive to produce, and the same could be accomplished by bigger hole with a mesh.  Also, many people will tell you that many mic response curves are smoothed, so there might be bumps in other mics as well.  I think the main limitation of these (and other similar capsules) is the diaphragm, and not the opening on them.

...but I'm open to correction.  Does anyone out there understand the physics of this stuff???

  Richard

[Church-Audio]

I would guess it's the hole pattern in the case, those apertures cause the bumpy stuff in the Primo's HF response (as shown in their specs).  This is why I've shied away from the Primos; I don't want to be troubled with modding the cases to fix that.  Also, the primos spec as -10dB at 20kHz, whereas WM61As will be up at 20kHz . . . which is easy to correct with EQ; the Primo's peaks and nulls would require a lot of narrow bands to correct.

Obviously I have my biases . . .

I'm not sure it is the holes that cause the 'bumps'.  The holes are over an area of something like 1/4" diameter or less.  Many mics have an opening larger than that, even small capsules.  My *guess* is the holes are there to allow a fairly large opening that is both mechanically strong and inexpensive to produce, and the same could be accomplished by bigger hole with a mesh.  Also, many people will tell you that many mic response curves are smoothed, so there might be bumps in other mics as well.  I think the main limitation of these (and other similar capsules) is the diaphragm, and not the opening on them.

...but I'm open to correction.  Does anyone out there understand the physics of this stuff???

  Richard

Diaphragm tension and thickness and closeness to the backplate among about 10 more parameters determine max frequency response. But lately a few companies have been using a technique of phase plug to "correct" frequency response. Most of the small holes in front of the capsule are as you say cheaper to make then using a mesh screen. But in some cases these small holes are an attempt to fix frequency response issues. The other thing that small series of holes vs a bigger hole give you is better shielding in front of the capsule for reduced induced noise.

[illconditioned]

I would guess it's the hole pattern in the case, those apertures cause the bumpy stuff in the Primo's HF response (as shown in their specs).  This is why I've shied away from the Primos; I don't want to be troubled with modding the cases to fix that.  Also, the primos spec as -10dB at 20kHz, whereas WM61As will be up at 20kHz . . . which is easy to correct with EQ; the Primo's peaks and nulls would require a lot of narrow bands to correct.

Obviously I have my biases . . .

I'm not sure it is the holes that cause the 'bumps'.  The holes are over an area of something like 1/4" diameter or less.  Many mics have an opening larger than that, even small capsules.  My *guess* is the holes are there to allow a fairly large opening that is both mechanically strong and inexpensive to produce, and the same could be accomplished by bigger hole with a mesh.  Also, many people will tell you that many mic response curves are smoothed, so there might be bumps in other mics as well.  I think the main limitation of these (and other similar capsules) is the diaphragm, and not the opening on them.

...but I'm open to correction.  Does anyone out there understand the physics of this stuff???

  Richard

Diaphragm tension and thickness and closeness to the backplate among about 10 more parameters determine max frequency response. But lately a few companies have been using a technique of phase plug to "correct" frequency response. Most of the small holes in front of the capsule are as you say cheaper to make then using a mesh screen. But in some cases these small holes are an attempt to fix frequency response issues. The other thing that small series of holes vs a bigger hole give you is better shielding in front of the capsule for reduced induced noise.

Can you explain what you mean by "phase plug"?
Also, how do small holes change the frequency response (as opposed to a single, larger opening)?
I would be grateful for some references (even just to others who say/use these terms).

I *do* know that adding a tube to increase the cavity size in front of a circular diaphragm increases the HF response.  Countryman B3 and DPA 406x both use this technique with "response grids" (generate peaks around 8kHz).  It is also done by adding little "spouts" on hearing aid type microphones such as the Knowles Acoustics FG series.  The things with these modifications is that they typically introduce a single peak, and not several bumps that Primo reports.

In terms of diaphragms it seems that the thinner the better (while still strong enough to hold the tension, I guess).  You'll often see boasts of "low mass diaphragm" that "accurately captures transients".  This typically refers to a 3 micron or so gold vaporized (or gold plated) diaphragm we expect to see on high end gear.

  Richard

[Church-Audio]

I would guess it's the hole pattern in the case, those apertures cause the bumpy stuff in the Primo's HF response (as shown in their specs).  This is why I've shied away from the Primos; I don't want to be troubled with modding the cases to fix that.  Also, the primos spec as -10dB at 20kHz, whereas WM61As will be up at 20kHz . . . which is easy to correct with EQ; the Primo's peaks and nulls would require a lot of narrow bands to correct.

Obviously I have my biases . . .

I'm not sure it is the holes that cause the 'bumps'.  The holes are over an area of something like 1/4" diameter or less.  Many mics have an opening larger than that, even small capsules.  My *guess* is the holes are there to allow a fairly large opening that is both mechanically strong and inexpensive to produce, and the same could be accomplished by bigger hole with a mesh.  Also, many people will tell you that many mic response curves are smoothed, so there might be bumps in other mics as well.  I think the main limitation of these (and other similar capsules) is the diaphragm, and not the opening on them.

...but I'm open to correction.  Does anyone out there understand the physics of this stuff???

  Richard

Diaphragm tension and thickness and closeness to the backplate among about 10 more parameters determine max frequency response. But lately a few companies have been using a technique of phase plug to "correct" frequency response. Most of the small holes in front of the capsule are as you say cheaper to make then using a mesh screen. But in some cases these small holes are an attempt to fix frequency response issues. The other thing that small series of holes vs a bigger hole give you is better shielding in front of the capsule for reduced induced noise.

Can you explain what you mean by "phase plug"?
Also, how do small holes change the frequency response (as opposed to a single, larger opening)?
I would be grateful for some references (even just to others who say/use these terms).

I *do* know that adding a tube to increase the cavity size in front of a circular diaphragm increases the HF response.  Countryman B3 and DPA 406x both use this technique with "response grids" (generate peaks around 8kHz).  It is also done by adding little "spouts" on hearing aid type microphones such as the Knowles Acoustics FG series.  The things with these modifications is that they typically introduce a single peak, and not several bumps that Primo reports.

In terms of diaphragms it seems that the thinner the better (while still strong enough to hold the tension, I guess).  You'll often see boasts of "low mass diaphragm" that "accurately captures transients".  This typically refers to a 3 micron or so gold vaporized (or gold plated) diaphragm we expect to see on high end gear.

  Richard

I can only find an AES paper on the subject and it relates to proximity effect. But it does also relate to condenser microphones.. The object is to unify the frequency response at a distance. The best example of this is the earthworks M30 measurement microphone. They use a series of grids in front of the capsule to defuse the sound so that it arrives evenly across the diaphragm. They do this by using a series of metal plates with holes in them. This is also one of the principles behind the DPA 4060 the capsule is sideway mounted inside a shell. This orientation gives you a diffused sound over the diaphragm. This helps even out frequency response. Its like a diffuse field microphone. This helps remove the directional aspects of the microphone. They can play with the length of the tube to increase the HFB or High frequency bump in the response as well.


Chris

[pool]

Interesting read but it is too technical now. If using mic jacks is the same path that the internals need, then I need external mics with same noise specs and sensitivty as the intermnal M10's. I am not after the same exact sound of the M10s....but same specs. Other mics with equal specs will be good. As you see im not that hard headed and changed my opinion.