Dynamic Loudness Control (DLC)
The Dynamic Loudness Control can counteract the dynamic loudness of an OEM radio or create one itself.
Many OEM radios automatically increase the bass and treble levels at low levels and automatically lower them again at higher levels.
Lowering the bass level at high volumes often protects the original woofer from being overloaded, while increasing the bass and treble levels at lower volumes is often requested by customers.
With the help of Dynamic Loudness Control, you can now decide for yourself whether and when something should be dynamically adjusted!
1. Opening the DLC
The DLC can be accessed via the IO menu item by selecting the Input EQ sub-item.
Click on the DLC icon to open the configuration menu.
2. Operation of the DLC
You can choose whether you want to use DLC only on the standard analog inputs or also on the analog inputs of any BRAX / HELIX / MATCH Extension Card.
In our case, we only use the analog inputs of the device, i.e. we select "Enabled on Analog Inputs".
You can also deactivate the function in the same way by simply selecting "Disabled".
We recommend recording a correlated pink noise for adjustment!
As soon as the signal is recorded, the volume level in -dB is displayed at the bottom of the window.
The lower the value, the quieter the input signal; the more the value moves towards 0 dB, the louder the input signal becomes.
Parallel to setting the DLC, it is advantageous to measure the input signal.
Please refer to our description of the Advanced Input Signal Analyzer (AISA) or the Input Signal Analyzer (ISA) to find out how to carry out this measurement with AISA or ISA.
Of course, the setting can also be made by simply listening to music at different volumes, but this requires a certain amount of experience.
We use the Advanced Input Signal Analyzer in parallel to set the DLC.
In our example, we first play the test signal quietly (-50.7 dB) and the incoming frequency response is measured in parallel with AISA.
The AISA window can be easily moved to view the complete measurement.
For example, the window was simply pushed down.
The measured frequency response can now be saved to Memory 1 (M1) by clicking the right mouse button.
We now repeat the same process at medium and full level, whereby the measurement curves can always be dragged to the same level using the left-hand slider and saved using the memory buttons (M1, M2, ...). This allows the curves to be compared directly with each other.
In this case, after three measurements, we can see that the stored measurement curves M1 (quiet), M2 (medium volume) and M3 (loud) hardly differ (apart from a slight ripple at extremely low levels in the blue curve).
This means that the radio does not have dynamic loudness.
If we now want to create a dynamic loudness, we can do this with the help of the DLC as follows:
The "Low Frequency Config" page refers to the bass range and the "High Frequency Config" page to the treble range.
The threshold values and the frequency of the shelf filter can be freely selected.
In our case, we want the bass frequencies for quiet music (-50 dB) to be boosted by 12 dB at 100 Hz using a low shelf filter. However, when the volume is increased to almost maximum volume (-5 dB), this increase in the bass level should fall back to 0 dB. In the range between the specified limit values, the bass range is now slowly adjusted dynamically.
We also want to reduce the level of the tweeter by 2 dB from high volume (-10 dB) to maximum level (0 dB) using a high shelf filter at 5000 Hz.
The dashed white line shows what the DLC is currently doing at the set volume.
Since we are now entering the input with a level of -31.1 dB, the low shelf filter has already been corrected to the middle range.
No change can yet be seen in the treble, as this would only be shifted from -10 dB to 0 dB at the input.
The following image shows the AISA measurements using exactly these DLC settings.
The red line (M1) shows a clear increase in bass, as this is measured at an input volume of -40 dB.
The blue line (M2) shows that the bass boost has already been partially reduced, but there is still no change in the treble, as this was done at an input volume of -20 dB.
The yellow line (M3) shows that the bass range has returned to the initial situation and the treble range has been reduced slightly, as this curve was measured with an input level of 0 dB.
This allows you to perfectly adjust your desired dynamic behavior by combining an AISA or ISA measurement with the settings in the DLC!