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Gear / Technical Help => Microphones & Setup => Topic started by: sasa999 on September 03, 2011, 04:44:19 PM
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I am looking for good internal mics for my Tascam recorder. Have read lot about EM172 mics. Low noise is OK, but how about sound quality for EM172 mics? I read specs - there is only 100 - 10 000 Hz at +4 -6 dB ??? What is over 10 000? Have you make any tests for music recording. Acoustic instruments - classical guitar, cello, violin...
There are some questions:
1. How they sound compared to Zoom H4n, Olympus LS-11 and Sony PCM-M10 recorder mics?
2. Are they better than Tascam DR-07 mics?
3. Can I find somwere any test recordings of EM172?
4. Is EM172 will work normaly with 2.5V power from Tascam DR-07 input?
5. Will be sound better if they connected as external mics with 9V battery?
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We had some storms pass through tonight (mostly wind) and I took some time to make a few recordings.
**WARNING** THESE ARE NOT PERFECT COMPARISONS - These recordings were done during differing weather conditions and at slightly different positions on my back porch. I have not done a great job level matching all the files, etc, etc...
These recordings were intended to be played back over headphones. The EM172 mics were gaff tapped below the sides of a baseball cap with the capsules facing forward, and located at about my temples. The Busman mics were positioned two different ways: HRTF and Spaced ~5ft. I had some descent sized wind screens on them so the spacing was wider than, and the position front to back on my head may have been quite a bit different than, the EM172s.
This is the R09HR's Internal mics with not much but wind and some distant traffic going on: http://www.adrive.com/public/05020888121fd798783b1b595ff43659b6fe26e0d3c7a519faf9753332024d81.html (http://www.adrive.com/public/05020888121fd798783b1b595ff43659b6fe26e0d3c7a519faf9753332024d81.html)
This is a pair of Primo EM172 mics plugged into the R09HR's PIP input (+3VDC through 2.3k Ohms) - some small distant thunder: http://www.adrive.com/public/88bab94eb85a1385a15ff4b9fef9159eef314da78c69a6ac781dc3d191ea1c8e.html (http://www.adrive.com/public/88bab94eb85a1385a15ff4b9fef9159eef314da78c69a6ac781dc3d191ea1c8e.html)
This is the same pair of Primo EM172 mics biased with +9VDC through 9k Ohms > low noise mic pre > R09HR's Line Input - my squeaky porch door and thunder:http://www.adrive.com/public/57861cbe23b7adf25b1f84d0e55a7628e2a13c6df94bc4cdce80b90cd65afb69.html (http://www.adrive.com/public/57861cbe23b7adf25b1f84d0e55a7628e2a13c6df94bc4cdce80b90cd65afb69.html)
This is the Busman BSC1K2 Omni mics HRTF'ish > low noise mic pre > R09HR's Line Input - wind and chimes: http://www.adrive.com/public/9b83a1c65eb29a745de342a1e16de12767902443a09a2968fb7237fc32036846.html (http://www.adrive.com/public/9b83a1c65eb29a745de342a1e16de12767902443a09a2968fb7237fc32036846.html)
This is the Busman BSC1K2 Omni mics spaced ~5ft > low noise mic pre > R09HR's Line Input - wind and rain:http://www.adrive.com/public/b9c5aab6c687847a5ae75cfac008012ba1f926e218ce6cf09dacdadb66266164.html (http://www.adrive.com/public/b9c5aab6c687847a5ae75cfac008012ba1f926e218ce6cf09dacdadb66266164.html)
The R09HR was set to 88kHz 24bit. All the fades and magnitude changes were done in Goldwave then I saved to FLAC 44k 16bit. No EQ was applied.
I'm interested to hear what people think of the differences.
-MIQ
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4. Is EM172 will work normaly with 2.5V power from Tascam DR-07 input?
5. Will be sound better if they connected as external mics with 9V battery?
Taken from http://www.frogloggers.com/BT%20EM172.htm
Operating Voltage 5 VDC (3 to 10V)
CAUTION:
The EM172 ECM must be operated at or near its nominal operating voltage. Operation at too low a
voltage will produce excessive self-noise.
Low voltage shortcomings might not be evident when you record ambient stuff like above, but is probably noticeable in a high SPL situation.
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Thanks for taking a listen sunjan!
The Primo datasheet does call out the voltage range sunjan posted (see attached). Operating at lower voltages reduces the sensitivity and can increase the self noise of the capsule. As sunjan also pointed out, the distortion the capsule produces when subjected to high SPL will rise as you lower the supply voltage and the wind/ambient stuff I recorded is not going to show that. However the original post mentions interest in recording acoustic instruments like acoustic gtr and cello. I doubt you would have any issues recording those instruments with this capsule powered by as low as 2VDC thru 2k Ohm. It won't handle its rated max SPL (122dBSPL ~ 3% THD) but I bet you could get descent performance up to 118dBSPL. The lower sensitivity will cause you to need more gain and the capsule will have considerably worse signal to noise though. Do we know what the load resistor is in the Tascam?
I'm surprised at the quality of the sound using 9VDC and 9k Ohm. The sample I posted sounds detailed and natural to me but I did use my head as the baffle :laugh:
-MIQ
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Did some tests Primo EM172 vs Panasonic WM61a vs Tascam DR-07 (mk1) internal mics http://taperssection.com/index.php?topic=149215.0 (http://taperssection.com/index.php?topic=149215.0)
My conclusion - EM172 is bad choice for recording music and acuostic instruments They are quiet, and sensitive but lack high frequencies.
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EM172 is bad choice
Sorry, I beg my pardon. EM172 is not as bad as it looks. I did some tests with sample resonators and got very usable frequency response.
There is comparision with WM61a before and after. Recorded on Tascam DR-07, line input.
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EM172 is bad choice
Sorry, I beg my pardon. EM172 is not as bad as it looks. I did some tests with sample resonators and got very usable frequency response.
There is comparision with WM61a before and after. Recorded on Tascam DR-07, line input.
What resonator did you use? Also, what testing method did you use?
Thanks,
Richard
PS: mic diameter should not matter that much, at least for direct sound sources.
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@sasa999: In your original post you noted that the specs allow -6dB @ 10kHz. I have looked at measurements of 100 of these capsules and seen only two that were -5dB @ 10kHz. The other 98 samples were between 0 and -4dB @ 10kHz with most between 0 and -2dB @ 10kHz. See the attached responses with the limit lines drawn on. Obviously there are some measurement anomalies above 12kHz and at very low freqs, but the trends are clear.
Where did you get these capsules? Do you have any others to test? I'd imagine that you could find other EM172 capsules that would measure quite a bit better, since these appear to be at the bottom of the spec. The sample recordings I posted (links are dead now :( ) were done with a pair that had responses that were matched but down about -2dB @ 10kHz. I wouldn't say they sounded dull.
@mshilarious: Jon, aren't you using something like this in your 10mm U-O mic? If yes, I imagine you've measured a fair number of capsules like these. Have you seen a HF roll off as bad as what sasa999 measured in any/many of your measurements? ??? The response curve you've posted at Naiant for the U-O shows a typical droop of about -2dB @ 10kHz right? That's about what I would expect for these capsules, especially if one has selected them somewhat carefully.
-MIQ
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@sasa999: In your original post you noted that the specs allow -6dB @ 10kHz. I have looked at measurements of 100 of these capsules and seen only two that were -5dB @ 10kHz. The other 98 samples were between 0 and -4dB @ 10kHz with most between 0 and -2dB @ 10kHz. See the attached responses with the limit lines drawn on. Obviously there are some measurement anomalies above 12kHz and at very low freqs, but the trends are clear.
Where did you get these capsules? Do you have any others to test? I'd imagine that you could find other EM172 capsules that would measure quite a bit better, since these appear to be at the bottom of the spec. The sample recordings I posted (links are dead now :( ) were done with a pair that had responses that were matched but down about -2dB @ 10kHz. I wouldn't say they sounded dull.
@mshilarious: Jon, aren't you using something like this in your 10mm U-O mic? If yes, I imagine you've measured a fair number of capsules like these. Have you seen a HF roll off as bad as what sasa999 measured in any/many of your measurements? ??? The response curve you've posted at Naiant for the U-O shows a typical droop of about -2dB @ 10kHz right? That's about what I would expect for these capsules, especially if one has selected them somewhat carefully.
-MIQ
Wow. Some serious measurements there!
The mics look really variable above 10k too. Are others, like Panasonic WM60/61 like this too? Or, are the small holes in the front of the Primo mics causing the variation?
Richard
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Hi Richard,
I believe the crazy variability above 10kHz is an artifact due to the test set up. When I've conducted simpler response measurements of these mics I haven't see any of the giant swings above 10kHz shown in my last post. Simple substitution comparisons between the EM172 and an Earthworks M30, for example, don't reveal any issues like that. I can see the HF drooping but not the wild swings above 10kHz. ???
-MIQ
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If you need lower noise with 61A, try mounting on a surface or putting a small sphere or plate around it. Then you will probably need some HF rolloff to compensate. You end up with a lower noise recording but the same excellent transient response you enjoy with the 6mm capsule, and also a bit of directionality as a bonus. That's my favorite approach.
I also like using variations on this.
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If you need lower noise with 61A, try ...... putting a small sphere or plate around it.
How do you mean it? Can you give some link for pictures or more explanation?
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What resonator did you use?
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What resonator did you use?
Remember though actuators need to be calibrated to the microphone your using. Simply changing adapters will not correct the frequency response. And when you are doing actuator measurements for a cardioid mic they will turn out vastly different in from the free field measurements. And you would also need actuator correction curves to get an accurate reading otherwise its not accurate. And comparing a card to an omni in an actuator does not tell you much.
Chris
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There are some tests
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If you need lower noise with 61A, try ...... putting a small sphere or plate around it.
How do you mean it? Can you give some link for pictures or more explanation?
DPA info on their small sphere mount attachments for omnis- http://www.dpamicrophones.com/en/Mic-University/Technology-Guide/Acoustic-Modification-Accessories.aspx (http://www.dpamicrophones.com/en/Mic-University/Technology-Guide/Acoustic-Modification-Accessories.aspx)
My DIY versions for mini omnis-
(http://taperssection.com/index.php?action=dlattach;topic=96009.0;attach=77797;image) (http://taperssection.com/index.php?action=dlattach;topic=96009.0;attach=88607;image)
Photos above are from this thread- http://taperssection.com/index.php?topic=96009.0 (http://taperssection.com/index.php?topic=96009.0)
..also details on what & why burried in there.
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Regarding the plotted mic tests.. I am curious what your repeatability is.
Specifically, how two back to back test compares. But also, how two tests compare where you remove the capsule from whatever mounting setup you are using, and then re-mount it.
Have you looked at that?
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Taken from http://www.frogloggers.com/BT%20EM172.htm
Operating Voltage 5 VDC (3 to 10V)
CAUTION:
The EM172 ECM must be operated at or near its nominal operating voltage. Operation at too low a
voltage will produce excessive self-noise.
Low voltage shortcomings might not be evident when you record ambient stuff like above, but is probably noticeable in a high SPL situation.
I am trying to order some of the 172s but can't find a seller online. ??? The frogloggers.com site seems to be take over by a virus.
Will anyone please suggest an online dealer in the USA for these and other Primo mics? I'd like to buy two or three of each of their omnis.
Thanks. :)