What is Accordo?
Accordo is a proprietary algorithm developed by Audison R&D to tune a car-audio system. Its goals are to reach the target frequency response, with excellent phase alignment.
To achieve this, first the system is measured. Accordo can use a USB measurement microphone, or it can use the bit Tune measurement system. In either case, a spectral weighting analysis is applied to the measurement which delivers almost identical performance as spatial averaging (but in a much shorter period of time). Accordo performs very brief measurement sessions.
Accordo then uses both delay and an innovative approach to DSP filter design to reach the objectives (target frequency response and phase alignment). Accordo repurposes a number of DSP “biquads” for use in creating IIR filters which address both magnitude and phase of the signal. (Accordo always reserves several biquads for use in further equalizing each output channel, if desired).
How good are the results Accordo delivers?
The results are very good! In repeated testing, Accordo delivers a tuned system with bass up front, a centered stereo image, and great sound! Of course, Accordo delivers the best results with the highest-performance ,fully-active systems.
What do I need to use Accordo?
You need a measurement microphone. This could be a USB microphone, an XLR microphone with a USB audio interface, or a bit Tune measurement system.
You will want a microphone stand for best results. Select a stand which does not damage automobile upholstery. The stand allows vertical microphone positioning, which often delivers the best results with Accordo.
You may use USB active extension cables to make sure the PC can be connected to both the microphone and the PC at the same time.
You may connect a clean source of 12V DC to the battery to maintain it during the Accordo process and the following audition period.
No test tones are needed for Accordo - it generates its own test tones.
What must I do to prepare the system for tuning with Accordo?
The most common issues when using Accordo come from installation error:
Incorrect input channel assignment.
Improper OEM input correction.
Output connection errors in polarity or driver assignment.
Therefore the most important preparation for using Accordo is proper QC testing of the installation.
With OEM integration projects, ensure a flat frequency response with time and phase alignment before performing the Accordo process. This is not needed with aftermarket sources.
If your measurement microphone has a calibration file available from the manufacturer, download it beforehand so it is available to use.
What do I do if there is a loud sound during the Accordo measurement process?
While this is very unlikely due to the short duration of the Accordo measurement process, it can happen - especially in a production environment. Click “Back” and repeat the measurement ss over.
How can I use Accordo in a commercial installation shop to deliver great sound to my clients?
Depending on the situation, there are basically three paths that you can follow. Which path you choose is generally a function of the performance the client is expecting, and the time available in the project.
First, perform proper QC as mentioned above. Then perform the Accordo process. Afterwards, follow one of the three paths below.
Accordo Level One - listen to the system, make any Final Tuning EQ adjustments by ear, verify rear levels, and finalize the file to the device.
Accordo Level Two - measure the overall system response using the bit Drive’s acoustic RTA and mono pink noise. Make any Final Tuning EQ adjustments based on this measurement. Then listen and make any additional adjustments to the Final Tuning EQ and rear levels. Finalize the file to the device.
Accordo Level Three - measure the left front, right front, and sub responses individually using the Acoustic RTA and mono pink noise. Use the Channel Tuning EQ adjustments to make sure that left front and right front match - if there is a deviation on one side, better imaging can be achieved by adding the same deviation to the other side. After left and right fronts match the target response, listen to the system and make any tonality adjustments using the Final Tuning EQ. Confirm rear levels.
Why doesn’t Accordo EQ the subwoofer?
Because the wavelengths involved are very long (making the measurement problematic) and the sonic improvement from EQing the subwoofer is very small. Many manual-tuning approaches also leave the subwoofer unequalized.. As with all the other output channels, the subwoofer channel output EQs can be used for fine-tuning the sound if desired.
Why do none of these paths involve changing delay settings?
Frankly, because in listening test after listening test, delay adjustments were not needed.
NOTE: Sometimes the subwoofer is the farthest speaker from the listener, but Accordo has assigned delay to the subwoofer and not to a cabin speaker. While the sub is usually in phase and the bass is “up front”, if you prefer the subwoofer to have a more traditional delay value, invert the polarity to the subwoofer and run Accordo again.
Why are Accordo’s delay settings so different from what I expected?
Accordo does not attempt to measure distance, but to optimize the phase interactions (in conjunction with adjustments made using Accordo’s IIR filters). Accordo does not attempt to approximate distances, but it does find delay settings which help us meet the objectives.
What if I want multiple Accordo tunes to compare various approaches?
This is very straightforward. Before the Accordo process is started, select the Memory Preset you want Accordo to write to. Then copy the results to other Memory Presets, and edit as desired.
How do I use Accordo for passthrough systems, such as a Silverado
with Bose using AP2 Widebands and AP690 woofers?
1. Using the Input EQ, EQ each input channel passband to flat.
2. Leave OEM delay and phase as it is.
3. When performing Accordo, uncheck “Time Alignment”
4. If you want to retain the 2-seat nature of the Bose system, make sure L and R Levels match for each stereo pair afterwards.
Can Accordo tune for multiple seats?
Accordo is currently focused on the main listening position. However, if you would like a 2-seat presentation, you can use Accordo to adjust for only Level and EQ (deselect Time Alignment).
Then raise the near-side levels to match the levels of the far side. This process works well in conjunction with the internal Upmixer (you may also want to adjust the center level for best results).
NOTE: The Listening Position marker in bit Drive is only for your use to differentiate the microphone position used in a given tune. The selected Listening Position does not affect the results Accordo provides. Each Memory Preset has the Listening Position defaulted to the center location in the vehicle.
How do I use Accordo with Upmixers?
- Accordo is not primarily intended for use with Upmixers. However, it can be used
for a basic Upmixer Tune. - Before running Accordo, un-check “Auto Time Alignment”.
- After running Accordo, make all the far-side levels match the near side.
- Optionally, copy all the near-side EQ settings over to the opposite far-side stereo channel (left tweeter over to right tweeter, etc.)
- After running Accordo, adjust the level of the center relative to the sides so that center tones are centered, but left-center or right-center tones are not.
NOTE: The Listening Position marker in bit Drive is only for your use to differentiate the microphone position used in a given tune. The selected Listening Position does not affect the results Accordo provides. Each Memory Preset has the Listening Position defaulted to the center location in the vehicle.
7. Windows Audio tips
Audison’s Bit Drive software runs on Windows PCs, and it can use microphones connected to those Windows PCs. In some cases, the default settings on a given Windows PC must be changed.
Windows Settings and Windows Control Panel
Windows Settings is a simplified version of the Windows Control Panel, but for advanced audio settings, access Control Panel -> Sound and check the Properties for individual Input Devices. (In Settings, type “Control Panel” in the search bar).
Audio Input Devices
A USB microphone has a built-in USB soundcard. XLR microphones require an external USB sound card. Either way, that sound card appears in Windows as an “Input Device” whenever it is connected to a USB port. Another Input Device is Audison Link. This appears in Windows only when bit Drive software is connected to an AF Forza amplifier via USB cable (it is not present when bit Drive software is operated in Offline mode).
Windows can enable and disable individual Input Devices. Make sure that the microphone/sound card you are using is enabled. Also make sure Audison Link is always enabled as an Input Device (disabling Audison Link will disable the Input RTA and also disable the Accordo Wizard).
Levels of Input Devices
If the Input Device level in Windows is set too low, this causes the Acoustic RTA to read low, and Accordo may not be able to detect signal properly. This can prevent the user from getting a green light in the initial calibration step - a red light would be displayed, with a text notification that insufficient signal has been detected. If the Input Device level is too high, Accordo may show a green light at the beginning of the calibration step (while the level control is still set to -24dB), or a red light may be displayed with a text notification that the level is too high. You may need to try a few times to find the right setting for your PC and your microphone.
Note: In the screenshot below, the Microphone level MUST be turned up. Also, the MUTE icons on the right must not show a red slash (indicating that the microphone is muted)
AGC and Enhanced Audio
Finally, Windows sometimes offers “AGC” or “Enhanced Audio Functions” for Input Devices. These can be seen in Control Panel, under Properties, Custom, or Properties, Advanced. Whenever AGC or Enhanced Audio Functions are offered, make sure they are disabled for both the microphone/sound card you are using and for Audison Link.