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SoundFirst SF101a Precision Microphone



SoundFirst SF101a case

The SoundFirst SF101a is a high stability precision omnidirectional phantom powered measurement or instrument microphone made in Colorado USA. Unlike most microphones in its price range it uses a real precision measurement microphone capsule by ACO with a titanium diaphragm.

While primarily designed for precision measurement work, the SF101a also makes a fabulous recording microphone with flat response, low noise, and a high maximum SPL. Use it anywhere you would use a top quality omni mic. Matched pairs or larger sets are available by special order.

Most microphones sold for measurement use in the under $1500 price range have plastic diaphragms. The combination of the diaphragm materials and the construction techniques used result in sensitivity to temperature extremes. Worse, a single exposure to high temperatures such as found in a car in summer, can result in significant permanent changes in response. Some manufacturers attempt to minimise these effects by "pre-aging" the microphone capsules before final assembly and calibration, but this does not remove the inherant instability of these capsules.

The SF101a instead takes the approach used in all the best and most expensive measurement microphones in the world, and uses a real precision measurement microphone capsule which was designed from the ground up for extreme stability under environmental extremes. These same capsules have been exposed to the weather on a mountain top for years and still meet their new specifications. Their sensitivity changes only 0.01 dB per degree C over the entire temperature range from -10 to +50 degrees C (14 to 122 degrees F). Exposure to 55 degrees C (131 degrees F) and 95% humidity (non condensing) changes the sensitivity less than 0.1 dB. Long term stability at 20 degrees C (68 degrees F) is greater than 250 years for a 1 dB change. SF101a typical noise is 13 dB SPL A-wtd, sensitivity is -36 dBV per Pascal, and maximum SPL is 138 dB for a 125 dB dynamic range.

The SF101a has a capsule diameter of 13.2 mm (0.520") so it fits IEC Standard calibrators for nominal 1/2" microphones. Few measurement microphones sold in its price range are the standard diameter making it difficult to calibrate them.

To protect your investment in this precision instrument, it comes packed in a waterproof case designed by Otter Box. This rugged case is filled with foam to securely hold your microphone and protect it from most normal conditions. This is a far more rugged and expensive case than other measurement microphones are supplied with, but I felt it was worth it to protect this high class microphone.

Of course the SF101a is supplied with an Individual Frequency Response Curve (IFRC) on the complete microphone, calibration data, and the original ACO factory response curve on the capsule. Each SF101a microphone comes with a stand adapter, IFRC, and a waterproof case designed by Otter Box.

Matched sets of SF101a are available by special order for those who need multiple microphones for use with Systune, Smaart, SIM or other multi-channel measurement systems.

The SF111a is a special order version of this mic with a Type 1 capsule. The sensitivity is about 4 dB higher and the noise floor is about 3 dB lower. The SF111a is supplied with an Individual Frequency Response Curve (IFRC) on the complete microphone, calibration data, and the original factory response curve on the capsule. Each SF111a microphone comes with a stand adapter, IFRC, and a waterproof case designed by Otter Box.

I am now stocking the ACO MATT-20 attenuators that fit between the capsule and the preamp body and reduce the sensitivity by 20 dB. They will work with any industry standard 1/2" mic capsule, and allow measurements to be made of high SPLs. Other attenuations are available on special order. The MATT-20 cost $195.00 plus $10.00 shipping.

The SF101a with stand adapter, IFRC, and a waterproof case designed by Otter Box is $890.00 plus shipping. The SF111a with stand adapter, IFRC, and a waterproof case designed by Otter Box is $1415.00 plus shipping. Ground shipping in the 48 states is $20.00 for one mic or $30.00 for two.

Purchase SF101a measurement microphone using PayPal. (PayPal Confirmed shipping address in 48 continental USA states only.)

Purchase SF111a measurement microphone using PayPal. (PayPal Confirmed shipping address in 48 continental USA states only.)

Purchase ACO MATT-20 attenuator using PayPal. (PayPal Confirmed shipping address in 48 continental USA states only.)


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Last Edited 5/5/2017

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