Notice of malfunction of the percentile sound level measurement function for the LA-7200/LA-7500/LA-7700 sound level meters

Thank you for your continued patronage of our products.
We have discovered a malfunction in the time-weighted noise level measurement function of our sound level meters LA-7200/LA-7500/LA-7700.
We sincerely apologize for any inconvenience caused to our customers.
We would like to inform you of the bug fixes and their implementation details as follows. Please review them carefully.

1. Target Products

2. Details of the problem

When using the LA-7200/LA-7500/LA-7700 sound level meters, errors may occur in the measurement results under the following conditions when repeatedly and continuously measuring the time-weighted noise level.

*Time-weighted noise level refers to the level at which, when the noise level fluctuates within a given measurement time (Meas Time), the time during which it exceeds a certain level accounts for N% of the actual measurement time. This level is represented by the quantity symbol _LN.
The measurement time (Meas Time) is the time taken for each measurement.
The total measurement time includes all measurement times (Meas Time) in repeated, continuous measurements.
Basically, the formula is "measurement time × number of measurements = total measurement time".
Period Time is a function that inserts a pause time between measurements.

[Affected measurement items]

Time-weighted noise level L _N (Lhi, L05, L10, L50, L90, L95, Llo, Lav, any two time-weighted settings)
The displayed values, Auto memory data, and command output data related to the above are included.

[Measurement conditions that lead to inaccurate measurements]

In the case of repeated continuous measurements with the following settings:

• Measurement Time: ON

• Total measurement time: ON

• Period Time (Period Time) :OFF

*This issue will not occur when the period time is enabled (Period Time: ON) during repeated continuous measurements.

[Details of the measurement error]

Correct Normal Operation (Figure 1): The time-weighted noise level is calculated over the set measurement time (Meas Time), and this is repeated over the entire measurement time (Total Time).

Incorrect operation of this malfunction (Figure 2): The time-weighted noise level is calculated from all results from the start to the end of the measurement.

Example: Measuring time 1 minute, Total time 3 minutes (3 repeated measurements)

This malfunction does not occur when the period time is enabled (Period Time is ON) during repeated continuous measurements.
Please note that for other measurement items (Lp, Leq, LE, Lmax, Lmin, Lpeak), the measurement results will be calculated according to the measurement time (Meas Time), regardless of the conditions.

3. Cause

There was a problem with the software processing inside the sound level meter.
The data related to the time-weighted noise level should have been reset at each measurement time (Meas Time), but there was an error in the reset process.

4. Response

We have prepared the corrected firmware (V4.5.0).
We apologize for the inconvenience, but please perform the firmware update.

5. How to update the firmware

5.1 How to obtain the firmware file

You can obtain the firmware file (LA7000Firmware.dat) from our website using the following method.

If this is your first time logging in, please click [New Registration]. If you are already registered, please click [Login] on the special page for users, proceed to the LA-7000 series user page, and download the firmware from there.
Please save the downloaded file to the root directory of your SD card.

5.2 Firmware Update Procedure

For detailed instructions on the firmware update procedure, please refer to the LA-7000 series FAQ, "Firmware Update Procedure."​

• Update instructions for the download page
• Instruction Manual, Basic Operation Section, "Firmware Update"
• "Firmware update procedure" in the installation guide

The same procedure is described there as well.

5.3 How to check after the update

Please check the updated version below.
Please check the "CPU Version" displayed under [Menu] - [General] - [Information/Update]. Confirm that it is version "4.5.0".

5.4 Others

If you request calibration or repair of your sound level meter, we will perform a firmware update during the calibration and repair work with your consent.

For updates, if you require pickup or have any other inquiries, please contact your nearest branch office.

6. Prevention of recurrence

We will enhance the comprehensiveness of our design reviews and development testing to ensure that defects are reliably detected. We will strive to prevent recurrence and improve product quality, and we ask for your continued patronage.

Regarding inquiries

If you have any questions, please contact our customer service department or your nearest sales office.