Cavern QuickEQ setup guide
What is QuickEQ?
Cavern QuickEQ is Cavern's advanced and customizable room correction software, bundled with the Cavern Driver. QuickEQ works with various devices, but uses Equalizer APO for calibrating the sound of PCs. This section of the documentation deals with the configuration of QuickEQ and exporting its results. On this page, in the other tabs, you can find each of QuickEQ's configuration panels' description. Export and other guides are available on the sidebar.
QuickEQ can be a one-click experience, but a single thing has to be set up first: the microphone. At least one calibration file has to be loaded on the Microphone tab for the calibration to properly work. The microphone selection is also critical, but 99% of the time, it's the system default and it's automatically used, but double checking is always a good safety measure. After that, you could start the measurement, the default settings are based on what most people like and what works on most systems. If you don't want to tweak the settings, look at one of the export documentations on the sidebar. This page and its tabs deal with everything you can modify about EQ generation. All settings can be changed after measurement, nothing requires measuring again.
Use these buttons to start a measurement, interrupt an ongoing measurement, or exit QuickEQ and return to the Cavern Driver.
Open the microphone's 90° calibration file here. Calibration microphones should be pointed upwards and calibrated to sound coming from around it. If only this calibration is given, it will be used for all speakers, otherwise the curve will be interpolated with the 0° calibration.
Open the microphone's 0° calibration file here. This is the calibration for sounds that directly hit the microphone membrane (from the top center speaker if the microphone is rotated correctly). If only this calibration is given, it will be used for all speakers, otherwise the curve will be interpolated with the 90° calibration.
Select your microphone here. The system should default to occasionally connected measurement microphones, but if you don't know if this is the case, make sure it's the active one by selecting your microphone here.
Settings related to the measaurement and correction target.
The length of the measurement in samples. The longer the measurement, the more precise and less noisy it will be. Recommended sizes are:
- 32768 - The minimal FFT size that supplies acceptable resolution for room correction. High frequencies can stilly be noisy.
- 65536 - For low volume measurements. In low noise environments (basically in most home theaters and even living rooms) higher values won't make a difference.
- 131072 - Compensation for high noise or low volume. If the measurement is still inconsistent, go higher.
Measurement signal volume relative to system output. The reference cinema level is -20 dB, home theater equipments are mostly using -30 dB. When the noise is low enough (two measurements after each other has the same result), this value doesn't matter, and choose the lower, don't damage your hearing.
Apply subsonic filtering
Remove low frequency signals from the speakers they are unable to reproduce efficiently. This can help protect the speaker, but might reduce audio quality. The feature is also useful for most cheap AVRs, which can't properly produce power on all channels simultaneously, as subsonic filtering reduces power draw.
Apply delays in the exported configurations to counteract different speaker distances and correct relative phases.
Choose between DCI (Digital Cinema Initiatives) and Cavern channel gain standards. DCI dictates that all surround channels has to be set to -3 dB relative to the screen speakers, and subwoofers have to be amplified by 10 dB. Cavern mode is mainly used for upconverting movies to Cavern's format, putting an emphasis on surround sound, and gaming, as it doesn't apply -3 dB to the surrounds.
Target curve to equalize the system to:
- Flat - No additional EQ is applied, each frequency response is flattened as much as Target EQ resolution allows.
- Room Curve - Frequently used home theater target curve with amplified lows and suppressed highs. A healthy mix of Depth and X-curve.
- Punch - Adds an emphasis on the chest slam range with noticeable falloff so compatible effects rise to a higher amplitude in the same time span.
- Depth - Adds a ramp to the subwoofer that keeps increasing the gain down to the end of the human hearing range. This can help increase the perceived low extension of the speaker.
- X-curve - The standard cinema curve, nearly all movies were mixed to this target and all cinemas are configured to this curve. Greatly suppresses high frequencies.
- Bandpass - Recommended for stage use, where the subwoofer level is changed all the time. This curve makes the transition to the subwoofers seamless at any volume difference if crossovers are not used.
This curve is only applied to LFE channels.
- Custom curve - Advanced users might load custom curves from TXT, FRD, or TARGETCURVE files. These are formatted the same way as calibration files, each line containing frequencies and their respective gains,
separated by a single space.
The following example somewhat resembles the Depth curve for low extension and has a moderate high frequency rolloff based on X-curve:
The file could be saved as TXT and loaded into Cavern, where the result is:
If the maximum system volume is still not enough after calibration and other volume options, this is the last resort for increasing it. The safeness of preset values show the likeliness of running into the 0 dB limit, thus the system compressor. The Auto option tries to determine the highest positive gain with the resulting EQs which won't hit the system compressor, making this the recommended option.
Target EQ resolution
Determines how strongly the curves are smoothed and how many EQ bands will be used.
- Low - Bands are 1/3 octaves from each other, LFE bands are 1/12 octaves from each other. Curves are smoothed to 1/3 octaves and LFE curves are smoothed to 1/12 octaves.
- Var - Bands are 1/12 octaves from each other, LFE bands are 1/48 octaves from each other. Smoothing starts as the High option and ends as the Low option.
- High - Bands are 1/12 octaves from each other, LFE bands are 1/48 octaves from each other. Curves are smoothed to 1/12 octaves and LFE curves are smoothed to 1/48 octaves.
- Full - The EQ is completely adaptive, bands are inserted wherever they are needed, at each local minimum and maximum. Curves are smoothed to 1/12 octaves and LFE curves are smoothed to 1/48 octaves.
Correction frequency range
Limit the generated EQ bands to this range. Contrary to popular beliefs, using limits like this will most likely result in worse sound. This feature should only be used in special cases, following tips about limiting the effect of the calibration is strongly not recommended.
Features in this box are not considered accurate, you should double-check their results. More information about them is visible as tooltips on mouse hover. For example, the Correct polarities option might mess up systems close to 90-degree polarity, so impulses should be manually checked.
Cavern Clear Center
This feature is designed to counter diffraction from centers with two low frequency drivers horizontally and/or poor acoustic treatment by simulating a worse acoustic environment. This should result in more human-like speech, less distortion, and a more uniform soundstage on the front. However, this feature will degrade well treated rooms with high quality equipment.
- PC used for correction
- 48 kHz system sample rate
- checked "Correct delays" option
- an extra WAV file next to the export
Cavern Sealing simulates the sound character of a sealed subwoofer on a ported subwoofer. This does not work the other way around!
The impulse response of a sealed subwoofer decays way slower than a ported one, in an oscillating manner. Cavern Sealing emulates this behavior on any ported subwoofer. Before applying Sealing, check the difference it makes:
- Optimized amplifier use - Since this feature spreads the required impulse power in time, any impulse effect applies way less strain on the amplifier: Light mode cuts the required power in half, while Heavy mode makes a tenfold difference. This reduces port noise a bit, but it can't be eliminated.
- Feeling changes - Only fast ported subs are capable of chest slams, sealed cabinets can only massage. Hard chest slams might fully disappear.
- Resonance prevention - Since the character has an oscillating element, pure sine waves will get amplitude modulated, reducing the hum that is commonly present in ported subs, even when calibrated properly.
- Musical character - A good ported subwoofer can barely be heard, only felt. This makes subwoofers only designed as LFE to have very poor quality when listening to music. Sealed subwoofers have good, warm musical character.
If you set any of the following modes, the feature will be enabled:
- Light - Tries to be a middle ground, by barely changing the sound character. This might get you some of the pros of a sealed subwoofer, like the musical character, but barely.
- Heavy - Aggressive, but not complete character transition, elongates impulses as long as it can without huge delays. Resembles a midrange sealed subwoofer. Simulating high-end sealed subs is possible, but it was not included in Cavern because of the huge delay that simulation requires.
Impulse response filtering. For multi-mic measurements, this feature is not available.
Show impulse responses
Change the displayed graphs from frequency response to impulse response.
Show verbose measurements
Display both the frequency and impulse response for each channel on the same panel with extra informations such as low frequency extension, phase, and RT60.
Left IR window
If you enable this options, you can window out samples to the left of the largest impulse spike. Only noise and harmonic distortion is present in this region unless heavy processing is applied on the system, so you can usually safely cut most of this region.
Right IR window
If you enable this options, you can window out samples to the right of the largest impulse spike. Reflections, low frequency details, and most noise are contained in this region, so expect a more precise but less detailed curve if you cut more samples.
Crossover frequencies for screen and surround channels, sounds below these frequencies will be moved to the subwoofer(s). Try to set them to the lowest frequencies your main channels can drive without any issues, based on the measured curves. Move the sliders all the way to the left to disable crossovers (which is their default state, as most systems already have crossovers).
Adjusts gains for the entire system to make sure the sounds moved to subwoofers can't hit 0 dB FS.
Use Cavern Ultimate Crossover Chain, an experimental bass management system dividing low frequencies across all channels. This feature requires completely disabled crossovers (other than Cavern's own) in the audio chain and high power amplifiers on most channels.
Crossover method. Use Cavern for maximum quality, instant crossover, and linear phase in small rooms, but that requires perfectly set delays. In other cases, Biquad will sound more uniform, but breaks phases. Synthetic biquad is the best of both worlds for large rooms: it's phase-perfect with the same frequency response as Biquad.
This is a debug interface to visualize how crossovers based on biquad filters behave. Their impact on the curve will not be exported as any crossover's spectrum distortion is measured and already corrected.
Use the multi-microphone measurement feature to create a more uniform listening space, which means the experience of multiple seats are closer to each other. To add a position, start a normal measurement, and use one of the Add this result... buttons after:
- Add this result to average - Used for every position except the reference detailed below. These results are only used for increasing the EQ precision.
- Add this result as reference - Used for the reference position, which is the center seat in home theatres, and the center seat 2/3 of the way to the back in the cinema. Delays, gains, and polarities are calculated from the reference position.
Recommended measurement positions up to 5 points
How to measure at over 5 points
Measure at the position of a single mic measurement first. Every other position should be randomly selected around it, with the following considerations:
- further than 50 cm from the nearest wall,
- not at 1/2, 1/3, 1/4... position on any axis,
- in line of sight from each tweeter.
When your system has more than 1 subwoofer, this panel will be active after measurement. Since multi-sub layouts are not available in any operating system, if you set up any output channel as a subwoofer, you need to downmix the system output after measurement. Cavern can do this for you, if you select one of the available downmix patterns. Any unmentioned channel for each option is a valid subwoofer output.
- 6.1 - 7.1 will be downmixed to 6.1.
- Stereo - 7.1 will be downmixed to front left/right.
- Quadraphonic - 7.1 will be downmixed to front and rear left/right. The first 4 channels will be used for this.
- 5.1 side - 7.1 will be downmixed to 5.1 with side surrounds.
- 5.1 rear - 7.1 will be downmixed to 5.1 with rear surrounds.