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Bedrock SMxx operating manual 

      

 

     © Bedrock Audio BV,  2019 

 

 

 

    

7. Level and spectrum

7.1 SPL meter

The Bedrock SMxx, as a Sound Pressure Level meter (also known as SPL meter or SLM) 
complies either with IEC 61672 Class 2 and ANSI S1.4 Type 2 (SM30 and SM50) or IEC 
61672 Class 2 and ANSI S1.4 Type 1 (SM90). It is classified as a group X instrument.

The SPL meter modules features three screens: SPL measurements, settings and browse 
measurements.

SPL measurements screen, during measurement (left) and with settings keyboard showing 

(right)

The following sound pressure level measurement settings are supported:

• 

Time weighting: Fast (F) and Slow (S)

• 

Frequency weighting: Z (linear, unweighted), A-weighted, C-weighted

• 

Max hold (holds and displays the maximum level during the measurement 
interval; used with either Fast or Slow time weighting)

• 

Equivalent continuous (EQ): computes the time-integrated level over the 
measurement interval; the level shown corresponds to the level of a contin-
uous signal containing the same amount of energy as the measured signal.

• 

Peak values (PK): the highest instantaneous value within an interval

Note that MAX and PK are not the same; MAX represents the highest measurement over 
a short time averaging period (either FAST or SLOW), and PK represents the highest 
instantaneous  value in the signal (even if this is a peak of very short duration). The SMxx 
allows PK measurements in combination with any frequency weighting, but only LCPK 
is commonly used.

Summary of Contents for SM30

Page 1: ...Bedrock SM30 SM50 SM90 Operating manual 2019 Bedrock Audio BV Document version 2 4 0 IEC 60268 16 rev 4 rev 5 IEC 61672 Class 2 ANSI S1 4 Type 2 IEC 61260 Class 0 ISO 3382 2 ANSI S12 2 ISO 1996 ...

Page 2: ...2 Bedrock SMxx operating manual ...

Page 3: ...iffer ent device model or a different firmware version the screenshots may not fully correspond to what is being displayed on your device s screen Where this manual refers generically to the Bedrock SMxx the corresponding text ap plies to all device models starting with the letters SM i e SM30 SM50 and SM90 All functions and features of the SM30 are identical to the SM50 with the exception of the ...

Page 4: ...ility measurements 16 6 1 Quick STIPA not featured on the Bedrock SM30 16 6 2 STIPA pro not featured on the Bedrock SM30 20 6 3 Full STI not featured on the Bedrock SM30 24 6 4 Speech Level Meter not featured on the Bedrock SM30 27 7 Level and spectrum 28 7 1 SPL meter 28 7 2 LAEQ logging 31 7 3 Real Time Analyzer RTA 35 7 4 Fast Fourier Transform analyzer 37 7 5 Statistical acoustics percentiles ...

Page 5: ...tructions 70 13 2 Power saving recommendations 71 13 3 Use of power banks and external battery packs 71 14 Cleaning maintenance and calibration 72 Battery disposal 72 15 Product warranty 73 16 Firmware updates 75 17 Buttons icons and symbols 76 18 Technical specifications 80 Linear range 31 Hz 4k 8k 12 5kHz 81 19 Troubleshooting 82 LED states 83 Firmware update error codes 83 EC declaration of con...

Page 6: ...these instruments are listed in section 2 of this manual Using the SMxx is quite easy thanks to its touch screen operation and intuitive menu structure Most users will get the hang of doing measurements with the SMxx without spending too much time with this manual Nonetheless we strongly recommend that you do read chapters 1 5 of this manual before using your SMxx for the first time in order to ge...

Page 7: ...672 ANSI S1 4 class 2 class 2 class 1 LAEQ logging long term monitoring RTA Realtime Analyzer 1 1 1 3 1 6 and 1 12 oct RTA logging long term monitoring of RTA spectra FFT Fast Fourier Transform spectral analyzer L statistical acoustics percentile levels such as L10 and L90 Room Acoustics RT60 Reverberation Time measurements ISO 3382 2 IR based and interrupted noise Noise curves NR NC etc ISO 1996 ...

Page 8: ...port from your Bedrock audio vendor please consult the Troubleshooting section chapter 19 Consult the section on Firmware updates chapter 16 before trying to in stall new firmware on your device Failure to follow firmware update in structions precisely may render your device permanently inoperable and voids your warranty Towards the end of this manual you will find detailed information in tables a...

Page 9: ...onal adapter suitable for your region Make sure that the device is switched off before transportation and storage During transportation and storage keep the device in a suitable casing or container preferably its original case The device needs to be protected from shocks and vibration due to transportation or falling excessive tem peratures liquids and moisture and any other external conditions th...

Page 10: ...y not exceed 5 5V As the USB power circuitry is connected to the battery pack excessive voltage applied to the USB port may cause the battery pack to catch fire or explode The XLR connector supplies 48V phantom power to the microphone This phantom voltage can be switched on and off through the hardware settings menu IMPORTANT connecting equipment not designed for 48V phan tom power to the XLR conn...

Page 11: ...on while the device is in operation you will see a dialog window asking confirmation before powering off If the power button is kept pressed for 10 seconds in the power on state the device will be forced into the off condition This can be used to reset the device if it becomes unresponsive keep pressed to 10 seconds to switch off then press again to restart 5 2 The SMxx main menu The Bedrock SMxx ...

Page 12: ...ring of spectra FFT Fast Fourier Transform spectral analyzer L calculate statistical levels such as L10 and L95 percentiles RTA Real time analyzer RT60 Reverberation Time meter Noise curves Measure curve based spectral single number ratings NR NC etc Os cilloscope Inspect audio waveforms in real time Polarity Check loudspeaker polarity AC Volts Measure output levels of audio equipment in dBU dBV a...

Page 13: ...nce of the main menu page after pressing set menu favorites After selecting a position tap choose module in the location you wish to place a module you can browse through the available modules To clear a position where your previously placed a module select the choose module placeholder from the list You can place re move and change modules in this menu screen as often as you like Apart from the m...

Page 14: ...ies in the battery charge indicator showing up either too full or too empty or causing the indicator to make sudden jumps If this should happen the best remedy is always to fully charge the device then fully discharge the device and then fully charge it again Note that the complete charge cycle may take 5 hours or more We recommend that you always leave the device connected to the charger until th...

Page 15: ...e calibrated so that full scale corresponds to 150 dB SPL You can play them back with any audio player although they may have to be amplified to be heard at a satisfactory level Windows is not set up to expect 32 bit audio files Back up your data via USB All of your measurement data and recorded audio can be copied to a PC using the supplied USB cable The SMxx simply presents itself as a mass stor...

Page 16: ...STI measurement you need a source of the STIPA test signal as well as an STI analyzer In your case the analyzer is your Bedrock SMxx You can choose whatever type of STIPA signal source that suits your application best TalkBox media player or otherwise The Embedded Acoustics reference STIPA test signal is included with the SMxx on a USB flash drive and can also be downloaded from the Bedrock websit...

Page 17: ...onsult tutorials and standards to make informed decisions about the STIPA signal playback level measuring positions number of repeated measurements etc The Quick STIPA module also shows some additional measurement information The A weighted sound pressure level The qualification band a letter between A and U that is used in some standards and defined in IEC 60268 16 rev 4 A label bad excellent tha...

Page 18: ...ss bar The save button is only operational when new unsaved measurement data is available from a finished measurement If this is not the case the save icon is colored gray The qualification band a letter between A and U is just a different way to represent the STI number it is fully redundant We currently recommend working only with the STI value itself unless the use of qualification bands is exp...

Page 19: ... Bedrock Audio BV 2019 19 A crossed out STI value means that the measurement is not yet sufficiently reliable ...

Page 20: ... noise spectrum to add to data Browse measurements review saved measurements Measurements are usually started from the STI and spectrum or the measurement de tails screen STI measurements are set up and started in the same way as when using the Quick STIPA module see above However in the STIPA pro module more details about the measurement are shown and the user has more elaborate options to config...

Page 21: ...lso shown mf TI the Transmission Index per octave band for each modulation frequency These measurement details will enable more experienced operators to determine not only the speech intelligibility of the tested channel but also the causes of intelligibility reduction induced by the channel Settings screen The settings screen gives the user three options Choose whether or not to display STI quali...

Page 22: ...d STI If you wish to add noise computationally the screen additive noise should be used to en ter the noise spectrum Note that the noise spectrum that you enter is only used if you also select the corresponding option in the settings menu entering the spectrum is not enough you also need to turn the additive noise feature on via the settings screen Additive noise screen A few remarks about adding ...

Page 23: ...rements saved in Quick STIPA can be browsed in STIPA pro and vice versa The measurement numbering range is shared between these modules This means that you can use STIPA pro to investigate measure ments done with Quick STIPA in more detail using the browsing screen in STIPA pro The settings you choose in STIPA pro additive noise level dependent masking affect the current measurement but also affec...

Page 24: ...de a reasonable alternative available The Full STI module now available on the SMxx fully implements every aspect of the Speech Transmission Index model making it the most universally applicable speech intel ligibility metric to date Fully compliant with the Full STI definition according to IEC 60268 16 Computes the complete 14x7 Modulation Transfer Function matrix Uses an efficient algorithm that...

Page 25: ...kbox starting May 2017 Note that the Full STI signal is copyrighted material all audio files of the signal released by Embedded Acoustics are watermarked Use of the signal other than directly with the SMxx requires a license from Embedded Acoustics The measurements themselves are no more difficult or complex to carry out than STIPA measurements The procedure is largely the same only the duration i...

Page 26: ...can be thought of as a compromise in between STIPA and Full STI Please refer to the section on the STIPA pro module 6 3 for a description of the various features and controls of the module additive noise qualifications bands disabling level dependent masking etc ...

Page 27: ...ses the correlation between SNR and subjective speech intelligibility In the 1990s a method was developed within Eu ropean ESPRIT project 2589 SAM to assess speech levels while removing the influence of natural pauses This method is known as Speech Level Meter SLM and is included in IEC 60268 16 as part of a normative annex Annex J This Speech Level Meter module is a direct implementation of this ...

Page 28: ...y weighting Z linear unweighted A weighted C weighted Max hold holds and displays the maximum level during the measurement interval used with either Fast or Slow time weighting Equivalent continuous EQ computes the time integrated level over the measurement interval the level shown corresponds to the level of a contin uous signal containing the same amount of energy as the measured signal Peak val...

Page 29: ... level that the microphone can handle overload Both types of range warnings are shown as a warning label next to the corresponding measurement value Range warnings are shown in both level fields if the signal level is either too low or too high such as in this example The limiting factor for the overall dynamic range of the measuring system is usually the microphone If the standard microphone is r...

Page 30: ...inuously the battery is drained relatively quickly within 3 4 For longer measurements we rec ommend using the charger or an external power bank Internal data storage especially if you are recording all measure ment audio per the option in the Settings module When re cording audio the internal storage fills up in about 5 hours When you press save data from the current measurement is stored Re sults...

Page 31: ...traffic light will be displayed to indicate whether the limit is currently being exceeded The log file is automatically saved and can be used to demonstrate that legal limits were not exceeded The LAEQ logging app measures three different metrics The LAEQ during a short time period between 1 and 60s This is level LAEQ cur rent can be thought of as the current contribution to the overall sound expo...

Page 32: ...veraging time can be adjusted to any period between 1 and 60 minutes The LAEQ15MIN as displayed on the screen is the moving average of a series of LAEQ current measurements The shorter the time period used for LAEQ current the more values are used to compute LAEQ15MIN and the longer your log file will become since a line is written for every LAEQ current period If you choose a short period for LAE...

Page 33: ... how much room there is below the limit In cases where noise events such as train passage are monitored the graph shows a recent history of events Settings screen the right picture shows the keyboad that appears when the change button is pressed to adjust the warning limit As with all modules the LAEQ logging module has a screen which can be used to set all parameters in this case LAEQ averaging t...

Page 34: ... page by page Each line shows the time the current level for the corresponding measurement interval the average LAEQ and an indication whether or not the limit was exceeded Long sessions may be broken into multiple files by pressing stop and immedi ately again start If the device crashes unexpectedly e g in case of power fail ure there is a chance that part of the log file may be lost By breaking ...

Page 35: ...ed in red bars while a second auxil iary spectrum is shown in blue lines The corresponding broadband levels are also shown to the right of the spectrum While the spectrum graph already gives a first impression of the spectral content of the measured signal you may wish to read the exact value in each band This is done by placing the cursor dashed line over the band of interest The cursor can be mo...

Page 36: ...wser are shown with the frequency weightings selected at the time the measurement is recalled even if these are different from the settings that were in effect during the measurement This allows you to inspect the effect of frequency weightings on all measurements saved previously Note that the spectrum and its corresponding broadband level are affected by the same time and frequency weightings In...

Page 37: ...o the full details of every measurement can be retrieved through USB by saving measurements FFT measurement screen The general look and feel of the measurement screen is similar to the RTA module but with a few differences First of all in line with the normal conventions frequency weight ings are not supported by the FFT module Secondly a button at the top right hand side of the graph can be tappe...

Page 38: ...dow blackman hamming rectangular etc is associated with a specific set of advantages and disadvantages relating to the FFT analysis We recommend studying the literature on spectral analysis or one of the many available online resources to choose the window that best suits your application For most non critical applications the settings selected by default hamming window with a window size of 8192 ...

Page 39: ... C Z FAST SLOW The operation and specifications of sound level meters are very specifically and precisely determined by IEC 61672 1 2013 However there is current ly no international standard that governs how the additional parameters that come into play with percentile levels should be chosen Implementa tions by various manufacturers while these appear to be consistent on the surface may differ Th...

Page 40: ...n the topic of time averaging we recommend choosing FAST The time averaging window is then set to 125 ms and opt for a measurement duration of 60 seconds or longer The percentile levels are computed according to the following procedure A level measurement takes place across audio frames of 512 samples at a sampling rate of 48 kHz A computation takes place after the acquisition of every new audio f...

Page 41: ... the spectral axis bandwidth between 1 12 and 1 1 octave the vertical axis is the time axis The latest spectrum is added consecutively to the bottom of the screen The measured level is indicated by means of color according to the legend displayed on the left side of the screen The RTA logging module does not feature a save button Measurement data is automati cally logged to an output file after ev...

Page 42: ...e impulse response of the room is obtained From this impulse response the RT60 is calculated Starting with firmware version 2 4 0 the impulse response method which previously not supported has also been implemented on the SMxx The test signal to be used is a loud short impulsive sound such as the sound from a starter gun Do not use sweeps or chirps as your test stimulus If you are using impulsive ...

Page 43: ...ect the correct method in the settings screen of the module IN for interrupted noise IR for impulse response based measurements e g with a starter gun The description of the module in this section of the manual will be based on the interrupted noise method We will indicate the differences for the IR method at the end of the section RT60 measurement screen armed for measurement but before a measure...

Page 44: ...d once the measurement is completed interrupted noise method Inspect the decay curves to visually verify that the measurement is correct An incorrect measurement which should be rejected may become apparent in any of the following ways The plotted data points do not reflect the expected linear decay of energy the level does not decrease linearly over time If this happens the triggering process may...

Page 45: ...red over 10 20 and 30 dB of decay the values of EDT T20 and T30 are always extrapolated to 60 dB of decay hence the name T60 the time it takes for the energy to decay to a level 60 dB below the starting level Cycle through EDT T20 and T30 using the button on the right Note that each of these three metrics is always calculated and saved for each measurement even if only one metric at a time is disp...

Page 46: ...o arrive at valid end results Note that averaging takes place on the level of the individualy measured data points along the decay curve so not just across individually measured reverberation times In the table on the measurement details screen a column is shown that indicates the status reliability of the current average measurement for the corresponding frequency A green checkmark indicates a he...

Page 47: ... is the preferred source of measurement noise If you are using a single non spherical loudspeaker avoid placement of the microphone on the loudspeaker axis Even though the microphone is om nidirectional avoid pointing the microphone straight at the loudspeaker When using the impulse response method use a starter gun or clapper that is capable of producing high level impulsive sounds Eliminate sour...

Page 48: ...ow warning s start time before knee point of the decay curve warning c correlation of the decay curve fit is low warning or acceptable depending on value Multiple letter codes may be stored with a single measurement value The description in this section was based on the interrupted noise method The procedure is similar for the IR based method after pressing arm generate the impulsive sound fire a ...

Page 49: ...sed originally by Beranek et al 1973 to yield a better correspondence with per ceived annoyance by putting more emphasis on the lowest frequency bands and highest frequency bands Balanced Noise Criterion NCB Standardized through ANSI S12 2 1995 similar in pur pose and application to NC apparently intended upon its introduction to replace NC Room Criteria RC This method is primarily used to quantif...

Page 50: ...rt the measurement Noise curves In this example the curves and rating for NC are displayed During a measurement the reference noise curves are shown as red lines The actual meas ured spectrum is shown as a blue line The cursor can be moved around to read the SPL at any of the frequencies The rating is shown as well as the LAeq level Only one Noise Curves metric can be displayed at a time but all m...

Page 51: ...019 51 The second screen of the module is used to set the duration of the measument Selecting curves and the associated rating method is done in the third screen of the module Choose from the available noise curve metrics ...

Page 52: ... the measuring time the choice whether or not to apply linear interpola tion on the data enabling or disabling frame averaging and a choice between acoustic and electric measurements If you are measuring sounds with the microphone mounted choose acoustic The amplitude scale will be expressed in the unit Pascal Pa If you are measuring without microphone but directly into the XLR input select electr...

Page 53: ...ies 48V phantom power to the microphone This phantom voltage can be switched on and off through the hardware settings menu IMPORTANT connecting equipment not designed for 48V phan tom power to the XLR connector with phantom power switched on may permanently damage the connected device and or the SMxx Disable phan tom power before connecting to external equipment The AC Volt meter function of the d...

Page 54: ...e can be set to display all levels in dBU dBV or dBuV corresponding to reference levels of respectively 0 7746 V 1 0000 V and 1 000 10 6 V Note that saved results are stored in separate folders named eRTA and eFFT separately from results for acoustic measurement data The SMxx is calibrated for electric inputs to the XLR completely separately from its acoustic calibrations The electric calibration ...

Page 55: ...s a configuration aid only it does not have options to save data as most measurement modules do The module is operated as follows play the test signal continuously over the sound system under test start the measurement on the SMxx bring the measuring microphone up close to the loudspeaker typically 0 5 to 1m de pending on the acoustics of the room and the configuration of the loudspeaker A little ...

Page 56: ... a fixed accurately know signal level usually 94 0 dB This makes calibration relatively easy insert the microphone tip into the port of the calibrator using an adapter with suitable dimensions for the microphone tip The device should now measure the nominal signal level produced by the calibrator For the SM30 SM50 Class 2 Type 2 calibrators are recommended such as the Cirrus CR 514 for the SM90 we...

Page 57: ...ion module has two editable fields acoustic calibration factor and electric calibration factor The acoustic calibration factor is the same param eter that is normally measured with a calibrator The second screen lets you enter calibration factors manually The electric calibration factor cannot be determined automatically with a calibrator it can only be changed by hand This parameter modifies the ...

Page 58: ...s up down Note that your changes are not applied until you press set clock Date and time in the settings module The Bedrock SMxx has an internal real time clock that keeps running even when the de vice is powered off The clock needs to be adjusted if the battery has been depleted com pletely for instance when the device has not been used for a very long time The system date and time are used for t...

Page 59: ... power on off selecting the preamp gain measuring range selecting the microphone type and selecting free field or diffuse field measurements The internal microphone amplifier of the SMxx features an adjustable gain setting Adjust ment of the pre amp gain is rarely needed since the system has a wide linear dynamic range However if you wish to connect an external signal source which operates at much...

Page 60: ... source into the XLR connector This option sets the overload underrange settings to the limits of the internal preamp electronics and sets all free field diffuse field corrections to zero If you plan to use a third party microphone with your SMxx you will need to obtain a so called mic ini file for that particular microphone Please contact support if you need access to third pary microphone data i...

Page 61: ...0 the brightness of the backlight can be adjusted This gives you the option to save power when using the device in conditions with low ambient light levels indoors Audio recording and text annotations The fourth screen of the settings module misc settings contains two settings audio recording and text annotations With audio recording set to ON the audio of each and every measurement is recorded on...

Page 62: ...or technical support you will be asked to provide some of the information displayed here such as the firmware version and hardware revision The current capacity of the battery pack is also shown here as well as the number of charge cycles to date he remaining data storage capacity and several other statistics related to the battery pack The status module is not used to make changes to the system b...

Page 63: ... link active will indicate that data is being transferred This will happen once an application initiates streaming audio from the Bedrock SMxx The audio signal is scaled so that full scale corresponds to 150 dB e g a signal with a level of 94 dB will correspond to a level of 56dB relative to full scale Windows drivers and ap plications may digitally adjust the level by applying software based volu...

Page 64: ...e the device However keep in mind that some of the internal software of the SMxx is run directly from the files displayed here If you remove or change any of these files your device will not work properly anymore Changes to files in the hidden system folder may render the device inac cessible through USB making it impossible to repair or update the system firmware through the normal procedure The ...

Page 65: ... the files to another extension than csv e g txt 11 5 Downloading recorded audio If the record audio option is turned on in the system settings then all audio recordings are saved in the same folders as the csv files with measurement data The following applies to stored audio recordings Audio is stored in wav format single channel 48 kHz floating point PCM which is easily read by many applications...

Page 66: ...our Bedrock SMxx is running on If the firmware version differs RemoteDisplay will prompt you to find the correct EAP firmware package on your local computer or automatically download it from the internet The remote display application does precisely what the name says you will get the exact same controls that you have on the Bedrock SMxx device itself but the entire display is simply moved to a wi...

Page 67: ... de pends on your version of Windows and your device settings The EAP package for the firmware on the connected device the same file used to update the firmware on the SMxx must be in the application data folder or the application will not run Note that RemoteDisplay will prompt you if it does not have the correct firmware available and offers you the option to download it from the internet direct...

Page 68: ... code and documentation please contact support bedrock audio com Through serial commands you can control virtually every function and control that the user also has control over via the display You can launch and terminate modules set pa rameters and start and stop measurements at will Measurement results can be read by a host application or results can be saved on the SMxx and then retrieved by a...

Page 69: ... Bedrock Audio BV 2019 69 This page is intentionally left blank ...

Page 70: ...he device for a prolonged period you can safely keep it connected to a charger A few charging tips A LED next to the USB shows the charge status While blinking alter nating between green and orange the battery is still charging The LED burns constant green as soon as the battery is full If you find over time that the battery capacity is reduced significantly com pared to its original capacity we r...

Page 71: ...of use Power conservation settings can be controlled from the device s hardware settings menu With its default settings approximately 350 STIPA measurements can be carried out over the course of an 8 hour day without recharging Some ways to extend the battery life Switch off the device when you do not plan to use it for a while Choose conservative power settings in the hardware menu The LCD back l...

Page 72: ... the touch screen provided that the following precautions are taken Do not spray cleaner directly onto the display Only use cleaning liquids specifically intended for LCD screens Battery disposal The device contains a 4 8v rechargeable NiMH battery pack At the end of the life cycle of this product care should be taken to dispose of this battery pack responsibly in compliance with rules and regulat...

Page 73: ...vers all defects except for those resulting from acci dents misuse including improper electrical connections and improper maintenance The following is explicitly excluded from product warranty Any damage resulting from dropping falling or excess vibration Any damage done by liquids including damage resulting from excessive use of screen cleaning liquids Any damage resulting from incorrect electric...

Page 74: ...x yourself as there are no user serviceable parts inside If you do see a legitimate need to open the device yourself please contact war ranty bedrock audio first so we can discuss preserving your warranty rights Please be aware that the product is protected by tamper proof seals A worldwide pick up return service is included in the warranty This means that we will have the defective unit picked up...

Page 75: ...he SMxx s internal file system can now be accessed from your computer in the same way as any mass storage device Copy the firmware updated package to the folder named updates Now restart the device using its power button The firmware update procedure will automatically start You will be able to see the progress of the update procedure on the LCD display The update may take up to 45 minutes de pend...

Page 76: ... if phantom power is enabled in settings Turns from grey to black is phantom power is active Audio recording indicator Showing if audio recording is enabled NB tap save to store Remaining battery charge Battery charging Operating on external power 0001 Measurement number Serial number of current measurement Instrument busy Occurs when switching modules Menu navigation Tap arrows to flip through me...

Page 77: ...itive noise according to the noise spectrum entered in the additve noise menu Adjust graph scale up down SPL meter module Overload indicator Underrange indicator Set time and frequency weightings Settings keyboard appears upon tapping this button RTA meter module Move cursor through frequency bands Tap left to move to lower frequencies right to move to higher frequencies FFT module Zoom controls w...

Page 78: ...ciently linear The result will be indicative of the true reverberation time but the measurement accuracy is not guaranteed On theoretical grounds or based on the measurement data the reverberation time measured in this frequency band is considered unreliable LAEQ logging module The A weighted equivalent continuous sound level LAEQ is below the preset limit This is true when considering the current...

Page 79: ...ly connected A data connection with Windows audio drivers may or may not have been established The USB data link is inactive No audio is streaming The USB data link is active and audio is being streamed digi tally to your computer An error occurred while setting up the data link ...

Page 80: ...ctive noise floor 25 dB A for class I devices SM90 or 30 dB A for class II devices SM30 SM50 Upper limit peak range 124 dB highest range 20 Hz 20 kHz Linear range See separate table below Maximum permissible sound pressure level is 155 dB Maximum electric input signal is 30 Vpp Microphone specs SM30 SM50 Microphone type BAMT2 48V phantom powered 1 4 omnidirectional free field microphone Conforms w...

Page 81: ...1 2006 EN 61326 1 2006 FCC part 15 compliant class A device Mechanical specs Size approx 210 x 85 x 55 mm excl microphone Weight 530 g including microphone Rear mounted tripod adapter Hook for carrying cord Bundled items Carrying case measuring instrument microphone USB charger int charger adapters US EU UK AU USB charging data ca ble manual carrying cord USB flash drive with test signals and soft...

Page 82: ...e after pro longed shelving Completely drain the battery and then fully recharge Repeat if necessary Device warms up during use Lack of ventilation Warming up of the device to temperatures of approx 35C 95F is normal If the de vice runs considerably hotter than that check ventilation and contact support if the problem persists Device not recognized by PC when connected through USB Driver problem D...

Page 83: ...ck on properties Click change settings Go to the policies tab Select Better performance instead of Quick re moval Error 18 File transfer failure The transfer of one of the packed files failed This may have various causes but most likely it is a possibly temporary issue with the internal file sys tem If you keep getting this error please contact support Error 19 Update package does not match device...

Page 84: ...which this declaration relates is in conformity with European Harmonised Standards as published in Official Journal of the EC Issue N A Issueof publication of the list of harmonised standards The compliance of the product has been based on the following standards EN 61326 2006 EMC Emissions EN 61326 2006 EMC Immunity EUT is suitable to be applied in residential and light industrial environments Ti...

Page 85: ...correction factors are given in this Annex for each type of microphone offered with Bedrock instruments The following microphone data are provided for all microphone types that are available with the Bedrock SMxx Typical free field response Since our microphones are free field microphones the free field response should ideally be zero for all frequencies but in practice small de viations occur par...

Page 86: ... given below Column 1 is the typical free field response of the microphone To en hance the accuracy of free field measurements users may subtract the typi cal free field response values in dB from the measured sound pressure levels per frequency band The typical free field response of column 1 is also used for periodic elec tric testing according to 61672 3 In that case the typical free field resp...

Page 87: ...0 0 0 100 Hz 0 0 0 0 0 0 125 Hz 0 0 0 0 0 0 160 Hz 0 0 0 0 0 0 200 Hz 0 0 0 0 0 0 250 Hz 0 0 0 0 0 0 315 Hz 0 0 0 0 0 0 400 Hz 0 0 0 0 0 0 500 Hz 0 0 0 0 0 0 630 Hz 0 0 0 0 0 0 800 Hz 0 1 0 0 0 1 1 kHz 0 2 0 0 0 2 1 25 kHz 0 2 0 1 0 3 1 6 kHz 0 3 0 1 0 4 2 kHz 0 3 0 2 0 5 2 5 kHz 0 3 0 3 0 6 3 15 kHz 0 3 0 5 0 8 4 kHz 0 3 0 7 1 0 5 kHz 0 4 1 1 1 5 6 3 kHz 0 4 1 8 2 2 8 kHz 0 4 2 9 3 3 10 kHz 0 4 4...

Page 88: ... 1 kHz 0 06 2 kHz 0 1 4 kHz 1 0 8 kHz 2 5 16 kHz 5 0 A1 3 Reflections from the instrument body when using the BAMT1 MP201 If the microphone is fitted directly on top of the SMxx without any length of XLR cable inbetween then reflections from the instrument body will affect measurements The table below gives the effect of those reflections per octave band To avoid these reflections use a cable with...

Page 89: ...creen per octave band is given in the table below Frequency Windscreen effect 31 5 Hz 0 0 40 Hz 0 0 50 Hz 0 0 63 Hz 0 0 80 Hz 0 0 100 Hz 0 0 125 Hz 0 0 160 Hz 0 0 200 Hz 0 0 250 Hz 0 0 315 Hz 0 0 400 Hz 0 0 500 Hz 0 0 630 Hz 0 0 800 Hz 0 1 1 kHz 0 1 1 25 kHz 0 1 1 6 kHz 0 1 2 kHz 0 2 2 5 kHz 0 2 3 15 kHz 0 3 4 kHz 0 5 5 kHz 0 6 6 3 kHz 0 8 8 kHz 0 7 10 kHz 0 3 12 5 kHz 0 2 16 kHz 0 5 20 kHz 0 4 ...

Page 90: ...ation is given below Column 1 is the typical free field response of the microphone To en hance the accuracy of free field measurements users may subtract the typi cal free field response values in dB from the measured sound pressure levels per frequency band The typical free field response of column 1 is also used for periodic elec tric testing according to 61672 3 In that case the typical free fi...

Page 91: ...0 0 0 100 Hz 0 0 0 0 0 0 125 Hz 0 0 0 0 0 0 160 Hz 0 0 0 0 0 0 200 Hz 0 0 0 0 0 0 250 Hz 0 0 0 0 0 0 315 Hz 0 0 0 0 0 0 400 Hz 0 0 0 0 0 0 500 Hz 0 0 0 0 0 0 630 Hz 0 0 0 0 0 0 800 Hz 0 1 0 0 0 1 1 kHz 0 1 0 1 0 2 1 25 kHz 0 2 0 1 0 3 1 6 kHz 0 2 0 2 0 4 2 kHz 0 2 0 3 0 5 2 5 kHz 0 2 0 4 0 6 3 15 kHz 0 2 0 6 0 8 4 kHz 0 1 0 9 1 0 5 kHz 0 1 1 4 1 5 6 3 kHz 0 2 2 0 2 2 8 kHz 0 4 2 9 3 3 10 kHz 0 6 4...

Page 92: ...1 1 kHz 0 06 2 kHz 0 4 kHz 0 5 8 kHz 1 8 16 kHz 4 8 A2 3 Reflections from the instrument body when using the BAMT1 MP309 If the microphone is fitted directly on top of the SMxx without any length of XLR cable inbetween then reflections from the instrument body will affect measurements The table below gives the effect of those reflections per octave band To avoid these reflections use a cable with ...

Page 93: ...creen per octave band is given in the table below Frequency Windscreen effect 31 5 Hz 0 0 40 Hz 0 0 50 Hz 0 0 63 Hz 0 0 80 Hz 0 0 100 Hz 0 0 125 Hz 0 0 160 Hz 0 0 200 Hz 0 0 250 Hz 0 0 315 Hz 0 0 400 Hz 0 0 500 Hz 0 0 630 Hz 0 0 800 Hz 0 1 1 kHz 0 1 1 25 kHz 0 1 1 6 kHz 0 1 2 kHz 0 2 2 5 kHz 0 2 3 15 kHz 0 3 4 kHz 0 5 5 kHz 0 6 6 3 kHz 0 8 8 kHz 0 7 10 kHz 0 3 12 5 kHz 0 2 16 kHz 0 5 20 kHz 0 4 ...

Page 94: ... kHz 6 5 16 kHz 5 5 A3 2 Typical free field response for the BAMT2 The typical free field response of the BAMT2 microphone is specified in this section Note that it is not feasible to perform actuator measurements with the BAMT2 as the micro phone capsule is not detacheable For instructions on how to perform periodic calibrations according to IEC 61672 3 which calls for a modified procedure for no...

Page 95: ...50 Hz 0 4 63 Hz 0 5 80 Hz 0 6 100 Hz 0 65 125 Hz 0 65 160 Hz 0 65 200 Hz 0 65 250 Hz 0 6 315 Hz 0 5 400 Hz 0 4 500 Hz 0 3 630 Hz 0 2 800 Hz 0 15 1 kHz 0 1 25 kHz 0 2 1 6 kHz 0 4 2 kHz 0 6 2 5 kHz 0 65 3 15 kHz 0 6 4 kHz 0 5 5 kHz 0 45 6 3 kHz 0 15 8 kHz 0 05 10 kHz 0 25 12 5 kHz 0 05 16 kHz 0 7 20 kHz 2 15 ...

Page 96: ...screen per octave band is given in the table below Frequency Windscreen effect 31 5 Hz 0 0 40 Hz 0 0 50 Hz 0 0 63 Hz 0 0 80 Hz 0 0 100 Hz 0 0 125 Hz 0 0 160 Hz 0 0 200 Hz 0 0 250 Hz 0 0 315 Hz 0 0 400 Hz 0 0 500 Hz 0 0 630 Hz 0 0 800 Hz 0 0 1 kHz 0 0 1 25 kHz 0 1 1 6 kHz 0 1 2 kHz 0 1 2 5 kHz 0 2 3 15 kHz 0 3 4 kHz 0 5 5 kHz 0 7 6 3 kHz 0 8 8 kHz 0 7 10 kHz 0 4 12 5 kHz 0 3 16 kHz 0 2 20 kHz 0 2 ...

Page 97: ... Bedrock Audio BV 2019 97 ...

Page 98: ...and preamplifier assembly as a whole this assembly is colloquially called the micro phone The BAMT2 is removable from the device allowing insertion of electrical signals into the system via the XLR connector This enables test labs to carry out tests for which insertion of electrical signals is needed in accordance with IEC 61672 3 2014 For electrical insertion of signals into the XLR input a test ...

Page 99: ...display range within the modules themselves does not have an impact on the measurement range just on which range of values are displayed in graphs on the display B 5 Reference range for linearity measurements The linearity of the SMxx is to be evaluated in the range 30 120 dB B 6 Wind spheres The wind spheres are not part of the standard configuration and need not be considered for periodic testin...

Page 100: ... weighted level must remain within 0 5 dB of its nominal value level calibration Generally speaking as long as the SMxx complies with requirements of IEC 61672 there is no concern regarding its compliance with 61628 16 given the fact that the device type and algorithms have previously been shown to comply For additional assurance a short series of tests can be done as part of periodic check ups of...

Page 101: ...move the microphone and pre amplifier and connect the line out of a Bedrock BTB65 Talkbox to XLR input into SMxx through attenuator set at 20 dB The level into the XLR input of the SMxx will be approx 32 dBU Select pink noise on talkbox In RTA mode set blue channel to LZEQ Check bands with cursor All 1 3 octave bands in the range 100 Hz 12 5 kHz must lie within 3 dB of the value at 1000 Hz Lineari...

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