Rew V5 + Umik-1
- PC or MAC computer with Room Equalizer Wizard V5.0 + the DSP A8 software installed WaveFlex
- 1 stereo RCA to 3.5 mm jack adapter cable
- 1 DSP A8
- 1 Microphone UMIK-1 with calibration file
- SPL calibration
- Hardware configuration:
- Software configuration
- DSP A8 configuration
- For DSP A8 owners with MCR Remote, turn down the volume before starting your first measurements.
- For DSP A8 owners without MCR Remote, simply attenuate the analog inputs level.
- REW configuration
- Soundcard tab
- Mic/Meter tab
- Level Calibration:
- REW software configuration
- House curve tab
- Analysis tab
- Equaliser tab
- Measurements of your speakers
To obtain a representative measurement of your sound levels, you need to calibrate the sound level first. We will use our calibrated microphone and the corresponding calibration file in REW to calibrate the entire measurement chain.
Connect the USB mic to the computer and the RCA-jack adapter to the headphones output of your computer and to the inputs RCA of the DSP A8.
In the volume control of your computer and/or in your sound card, deactivate the entire virtual sound ambiance or other sound enhancements processing. In window sound level main tab, set Wave Volume and Main Volume to maximum.
Open the DSP A8 software and configure the routing table as shown (Only input 1 is used and routed to all the outputs).
Configure all the 8 outputs channels without any X-over/EQ/Delay/gain filter. Mute all speakers but the 2 door’s speakers (channels 5 & 6 in the example hereunder) and Connect & Synchronise to DSP A8.
The main level needs to be attenuated during the measurement process.
Be careful: without attenuation the sound level might damage your installation
At REW start up, a pop-up window will indicate the detection of a USB mic and ask you to confirm it:
The next window allows you to load the .txt calibration file of your microphone.
Open now the Preferences menu and configure the different tabs:
Check that Umik-1 mic is selected as Input Device.
Select headphone output as Output Device (see green box).
Set the parameters as shown in the blue box
Check that the right calibration file of your mic is used and that Z-weighted are selected.
Open Generator and SPL Meter Windows and configure it as shown hereunder.
SPL meter window: select SPL mode, fast analysis and micro Z-weighted.
Generator window: Use PINK NOISE from 500 to 2 KHz at -3db.
Start the generator and the SPL meter (play and record button) and increase slowly the volume of the MCR Remote (or the analog input level) to obtain a SPL value of 75db.
Once the volume set to 75dB, you can stop the signal generator and the SPL meter. Do not touch the volume control anymore. The set volume will be used for all your measurements.
The REW software is now almost configured do not modify the Sound card tab parameters.
I recommend you to save the actual DSP A8 configuration file with the calibrated input level and all the outputs set to flat, for instance as: a8presetmesure.xml
Now let’s look at the others tabs of the Preferences menu.
This tab allows you to import a target curve which will show in the EQ menu. This curve is used for the X-over and equalisation simulation process. We will see later how to use that tool and the target curve generation process.
The interior car acoustical environment is totally different to that of a living-room. The parameters hereunder are the default parameters you have to set.
This tab lists all the DSP units compatible with the REW software. Select DSP A8
In Target Defaults (yellow box) you can configure the overall target curve for the entire system but also for specific type of speaker (full-range or sub for example).
So you say, what’s the difference between this menu and the House curve menu?
The 2 target curves are used for different purposes:
In the House curve they are used for the set-up of a single speaker
In the Equalizing menu they are used for the overall setup of the entire system
You will find a lot of useful information on the internet, what the shape of a target (frequency) response curve should look like. The set-up of your car is a matter of personal taste though; play around with the curve to your personal liking.
The parameters shown hereunder are purely indicative and remotely inspired from the ISO 2969 norm.
The REW software and the DSP A8 with the presetmesure setup are now configured; we can start measuring our speakers. Again, do NOT alter the volume settings, both on input attenuator (software) and MCR remote from now on. If you find the actual volume to high during your measurements, turn the volume down and start all measurement again with that lower volume.
Click on the Measure button and set the signal parameters.
For the woofers, the mids and subs use a signal from 20 Hz – 20 KHz.
To protect your tweeters we suggest using a signal from 500 Hz – 20 KHz only.
In the DSP A8 software select the speaker you want to measure by muting all the other speakers.
You can now click on the Start measuring button.
The sweep signal will now be generated through your system and recorded by the microphone.
You obtain your first frequency response curve.
Repeat this procedure for each and every speaker using the signal parameters as indicated before.