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[Peter Kowalczyk]

Hi folks,

I recently got a great deal on an Earthworks "Smaart S30" mic through the lab marketplace

Searching for info on the S30, however, I don't see it anywhere on Earthworks' site; it appears its only sold through Rational Acoustics.  R.A.'s website claims the mic's response extends to 23kHz, and it measures 165mm in length, which makes me think it may simply be a re-badged Earthworks M23.  However, the frequency response chart included with the mic shows response to 30kHz.

Does anyone know where the S30 fits into Earthworks line of measurement mics, or where I can find some more info? 

Thanks!

[Arthur Skudra]

Hi folks,

I recently got a great deal on an Earthworks "Smaart S30" mic through the lab marketplace

Searching for info on the S30, however, I don't see it anywhere on Earthworks' site; it appears its only sold through Rational Acoustics.  R.A.'s website claims the mic's response extends to 23kHz, and it measures 165mm in length, which makes me think it may simply be a re-badged Earthworks M23.  However, the frequency response chart included with the mic shows response to 30kHz.

Does anyone know where the S30 fits into Earthworks line of measurement mics, or where I can find some more info? 

Thanks!

It is the equivalent of an Earthworks M23.

[Peter Kowalczyk]

It is the equivalent of an Earthworks M23.

Okay, thanks for confirming!

Peter

[Peter Kowalczyk]

To follow up, I had my new measurement rig (S30 -> USBpre2 -> Smaart7 DI) in monitor world last weekend, where it was excellent to be able to precisely EQ out some variance between wedges, and to pinpoint problem frequencies. 

It became obvious during showtime that the sensitivity of the S30 is VERY HIGH.  Even with the -15dB pad engaged on the preamp, I was still occasionally clipping the ADC, and it wasn't an especially loud show.  Spec sheet says the S30 generates 30 mv/Pa nominal, while my particular unit's calibration sheet claims 33mV/Pa.
This started me wondering, so I pulled the sensitivity specs of a few other common measurement mics:

Brand              Model      Sens (mV/Pa)     difference
Earthworks       S30         30
DPA                4007        2.5                   (-21.6 dB)
Josephson        C550H      10                    (-9.5 dB)
Audix              TM-1        6                      (-14 dB)
Rational           RTA-420   7                      (-12.6 dB)

... The Earthworks leads the pack by a big margin.  The other M-series mics are also spec'd at 30mV/Pa per the Earthworks' website. 

So why such a high sensitivity?  Is there a benefit that I'm not seeing - perhaps lower (equivalent) self-noise since less preamp gain is required?

I would, perhaps, just stick a passive attenuator in-line, but I'm concerned that it would change the frequency response... (guess I can measure it to be sure)  How would you get some more 'headroom' out of this measurement setup for loud shows?

[Hayden J. Nebus]

To follow up, I had my new measurement rig (S30 -> USBpre2 -> Smaart7 DI) in monitor world last weekend, where it was excellent to be able to precisely EQ out some variance between wedges, and to pinpoint problem frequencies. 

It became obvious during showtime that the sensitivity of the S30 is VERY HIGH.  Even with the -15dB pad engaged on the preamp, I was still occasionally clipping the ADC, and it wasn't an especially loud show.  Spec sheet says the S30 generates 30 mv/Pa nominal, while my particular unit's calibration sheet claims 33mV/Pa.
This started me wondering, so I pulled the sensitivity specs of a few other common measurement mics:

Brand              Model      Sens (mV/Pa)     difference
Earthworks       S30         30
DPA                4007        2.5                   (-21.6 dB)
Josephson        C550H      10                    (-9.5 dB)
Audix              TM-1        6                      (-14 dB)
Rational           RTA-420   7                      (-12.6 dB)

... The Earthworks leads the pack by a big margin.  The other M-series mics are also spec'd at 30mV/Pa per the Earthworks' website. 

So why such a high sensitivity?  Is there a benefit that I'm not seeing - perhaps lower (equivalent) self-noise since less preamp gain is required?

I would, perhaps, just stick a passive attenuator in-line, but I'm concerned that it would change the frequency response... (guess I can measure it to be sure)  How would you get some more 'headroom' out of this measurement setup for loud shows?

Your interface spec for mic input clipping is +4dBu with pad engaged, or about 1.23VRMS. Per the mic spec of 0.03V/Pa, this setup should run out of headroom at around 40Pa, or 126dB, per:

20log(1.23/0.03)  [which gives you the difference in dB between the preamp input clip and the mic sensitivity spec]
+
94dB  [ 1Pa, or the SPL level at which sensitivity is spec'd]
=126dB and some change.

If you want the mic and input to clip at the same time (142dB SPL) you need an additional 15dB pad, however you'll have fairly low measurement levels at moderate (not painful)  SPL.  A purely resistive pad should be linear. You could also employ an external phantom supply and use the line input on the interface (+28dBu @ clip), which would put mic clipping at -10dB from ADC clip, but would have similar drawbacks at reasonable SPL.

 

 

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