iDSP INSTALL GUIDE
Auto Room Correction With iWoofer Pro (Paid App)
The premium version of the app (iWoofer Pro, $5) is only available on iOS.
NOTE: If using the free app skip the Auto Room Correction section.
Even with high-class speakers and subwoofers, the complexity of room acoustics can cause nonlinearities in audio
signals once the sound bounces around your room and eventually reaches your listening position. Room reflections
combined with the direct sound from a speaker will usually create a misrepresentation of your audio signal, meaning what
you hear is not the same as what the recording /mastering engineer heard in their studio. Phasing issues are especially
true with the very long wavelengths of bass frequencies, as they wrap around the whole room and then eventually
find their way to your listening position. Room reflections are the main reason that recording engineers go through the
extraordinary effort with room treatment, speaker placement, and sometimes precise EQ to make their studios and
speakers have a flat response as possible. Flat response means the audio signal is represented accurately (it will look like
a straight, horizontal line when taking frequency response measurements).
Room correction is powerful because it can take a measurement of your listening position, and apply precise FIR filters to
automatically ‘flatten’ the response and minimize any adverse effects of room acoustics. The Automatic Room Correction
algorithm works by taking a measurement right next to your subwoofer (a near field measurement) and then takes more
measurements in your listening position to determine what DSP parameters need adjusting for optimum room correction.
If you look closely, you will see that your near field response will look more like a flat line while your listening position
measurement will likely look more ragged as represented by dips and peaks throughout. Depending on which type of
correction you choose, the app will apply equalization to make your listening position more faithfully represent the original
audio signal.
Before You Begin
- For optimal results, take off any case you might have on your iOS device. Because the microphone on your iOS
device was calibrated for the iWoofer app without a case on, your case can cause inaccuracies in measurements due to
diffraction.
- Make sure to follow the “AVR and Subwoofer Amplifier Settings” section earlier in the manual before proceeding with
room correction.
- In the X-Over menu of the iWoofer app, set your desired high pass (subsonic filter) and low pass filters for your
subwoofer. These settings are used by the room correction function to determine how high and low to correct the
frequency response. If you decide to change these crossover points after doing room correction, you will need to rerun
the room correction function for optimal results.
- Remove all EQ settings you might have made in the X-Over menu.
- If a sweep is not audible while running the AutoEQ, make sure your sub is powered on, and the audio connections are
correct. If the sweep is not audible once confirming the subwoofer is connected correctly, try restarting the app and
or removing and then reconnecting power to the iDSP hardware unit. The iDSP unit has a standby function and will
temporarily shut off if it does not receive input for a period of time, but you can quickly kick it out of standby with a
power cycle.
- Turn off any input signal going into your iDSP, so it does not interfere with your measurements.
iDSP manual rev1 simon.indd 8
12/7/20 8:28 AM
