Car audio crossover settings are the first line of defense for your speakers. Set the high-pass too low on a tweeter and you'll burn it out within an album. Set the low-pass too high on a subwoofer and the bass localizes into the trunk. This guide gives you the specific frequency, slope, and filter direction we set on every customer system, organized by driver size from 1-inch tweeters up to 15-inch subwoofers.
Key Takeaways
- High-pass filters protect drivers from excursion damage; low-pass filters keep them out of frequency ranges they cannot reproduce cleanly.
- Our recommended starting point for a 1-inch dome tweeter is HP 3,500 Hz at LR4 (24 dB/oct).
- Default slope for active car audio crossovers is Linkwitz-Riley 24 dB/oct (LR4). Use LR2 or steeper Butterworth only with a specific reason.
- Match the high-pass on the upper driver to the low-pass on the lower driver at the same frequency and slope for clean acoustic summation (BestCarAudio.com).
- Low-pass too high on the subwoofer is the most common car audio crossover mistake. Above roughly 80 Hz, the ear localizes the bass.
What Are Car Audio Crossover Settings, and Why Do They Matter?
A crossover is a filter that blocks part of the audio signal from reaching a speaker. Car audio crossover settings have three parameters per driver: the high-pass frequency, the low-pass frequency, and the slope of each filter. High-pass means everything below the set frequency is attenuated. Low-pass means everything above is attenuated. A bandpass driver (like the midrange in a 3-way active front) uses both.
Why does it matter? Two reasons. The first is driver protection. A 1-inch dome tweeter playing 200 Hz at any meaningful volume forces the voice coil past its mechanical limits, heat builds inside the gap, and the coil delaminates from the former inside a song or two. The high-pass filter blocks those frequencies before they reach the tweeter (JL Audio).
The second reason is frequency-overlap cancellation. If two drivers play the same band at the same time but their cones sit at different distances from your ears, the two signals arrive with a small time offset and partially cancel. The result is a dip in the response curve at the overlap frequency. A clean crossover handoff makes one driver dominant per band and prevents the cancellation.
A properly tuned car audio crossover is the difference between a system that images sharply and one that smears. It is also the difference between drivers that last 10 years and drivers that last 10 weeks. We set crossovers on every customer system before time alignment, level matching, or EQ. Skip this step and the later steps cannot compensate for what the speakers physically cannot do.
Recommended Car Audio Crossover Settings by Speaker Size
These are the specific starting frequencies we set on every customer system, organized by driver size. Each row is a starting point. Adjust based on your driver's published F3, the in-cabin response, and your listening preference, but start here. All slopes are Linkwitz-Riley 24 dB/oct (LR4) unless noted (BestCarAudio.com).
| Driver | High-pass | Low-pass | Slope | Reason |
|---|---|---|---|---|
| 1" dome tweeter | 3,500 Hz | none (run wide open) | LR4 | Protects the dome from Xmax-induced rocking below resonance |
| 1" compression tweeter (horn-loaded) | 2,000 Hz | none | LR4 | Compression drivers handle low-end excursion better than dome tweeters |
| 3" midrange | 250 Hz | 5,000 Hz | LR4 | Mates with most 1" tweeters and most 6.5" mid-bass drivers cleanly |
| 4" midrange | 200 Hz | 4,000 Hz | LR4 | Slightly wider band than the 3" because the larger cone handles lower frequencies |
| 6.5" mid-bass | 80 Hz | 3,500 Hz | LR4 | Door install; HP at 80 Hz protects from cabin pressure and door panel resonance |
| 8" door woofer | 60 Hz | 800 Hz | LR4 | Bandpass between sub and mid; LP at 800 Hz keeps midrange clarity |
| 10" subwoofer (sealed) | none | 80 Hz | LR4 | Above 80 Hz you start hearing the trunk instead of the front stage |
| 12" subwoofer (sealed) | none | 70 Hz | LR4 | Larger cone needs a slightly lower LP for the same coherence |
| 12" subwoofer (ported) | box tuning + 5 Hz | 80 Hz | LR4 | HP protects from below-tuning unloading damage |
| 15" subwoofer | none (sealed) or tuning + 5 Hz (ported) | 60-70 Hz | LR4 | Large cone gets localized faster; keep LP tight |
Two notes on this table. The high-pass on tweeters is non-negotiable. Running a dome tweeter below 3,000 Hz with anything above whisper level is how you kill tweeters. The low-pass on subs is the second-biggest call you'll make: 80 Hz is the threshold of localization for most listeners and most cabins, so any LP above that lets you hear where the sub is.
How Do You Pick the Right Crossover Slope?
For active car audio crossovers the default is Linkwitz-Riley 24 dB/oct (LR4). When you set the high-pass on the upper driver and the low-pass on the lower driver to the same frequency and slope, LR4 sums to flat response at the crossover point. Most DSPs default to LR4 for this reason (Crutchfield).
When to step down to LR2 (12 dB/oct)
Use 12 dB/oct when the driver is well-behaved past the crossover and you want a gentler transition. Some 4-inch midranges and most subwoofers tolerate LR2 just fine. A gentler slope sounds more natural in midrange handoffs but offers less driver protection on either side of the crossover point.
When to go steeper (Butterworth 36 or 48 dB/oct)
Use 36 or 48 dB/oct when the driver has a sharp resonance or breakup just outside the crossover. A 1-inch dome tweeter with a 1.2 kHz resonance might need a 48 dB/oct high-pass at 2,500 Hz to keep that resonance from being excited at moderate volume. Steep slopes also help on subwoofers where you want a tight LP against the midrange roll-in.
Why slopes should match across the crossover
Mismatched slopes on either side of the crossover create a phase rotation that varies with frequency, which the brain hears as a smeared transition. If your tweeter high-pass is LR4 at 3,500 Hz, your midrange low-pass should also be LR4 at 3,500 Hz. This is called slope-mirroring and is the cleanest way to set up an active crossover.
How Should You Match Crossover Points Between Adjacent Drivers?
Matching crossovers between two adjacent drivers is the part most DIY tunes get wrong. The rule: the high-pass on the upper driver and the low-pass on the lower driver should use the same frequency, slope, and filter type (BestCarAudio.com).
Tweeter-to-midrange handoff
For a 2-way active front with a 1-inch dome tweeter and a 6.5-inch mid-bass, mate them at 3,500 Hz LR4 on both sides. The tweeter HP is 3,500 Hz LR4; the mid-bass LP is also 3,500 Hz LR4. At the crossover point each driver runs at -6 dB and they sum to 0 dB, which is flat acoustic response.
Mid-to-midbass handoff in a 3-way active front
For a 3-way with a 3-inch midrange, mate the midrange LP to the mid-bass HP at the same frequency. Typical values: midrange LP 250 Hz LR4, mid-bass HP 250 Hz LR4. Change one side, change the other to match. The midrange in a 3-way active front is a bandpass driver, meaning it has both HP and LP filters working at the same time.
Midbass-to-subwoofer handoff
Mate the mid-bass HP to the subwoofer LP at 80 Hz LR4 in most cases. Some installers prefer a small overlap, where the mid-bass HP is at 70 Hz and the sub LP is at 80 Hz, to fill a thin spot caused by a cabin null. The overlap introduces a small risk of phase smearing. We use slope-mirroring with no overlap as the default and add overlap only when measurement shows we need it.
Common Car Audio Crossover Setting Mistakes
High-pass set too low on tweeters
The fastest way to kill a tweeter. A 1-inch dome tweeter playing 800 Hz at any meaningful volume forces the voice coil past the spider's mechanical limit, heat builds, and the coil delaminates from the former. Set HP at 3,000 Hz minimum on most dome tweeters. Tweeters survive years at 3,500 Hz; the same tweeters die in weeks at 1,500 Hz.
Low-pass set too high on the subwoofer
Above roughly 80 Hz the human ear can localize sound. If your subwoofer LP is at 100 Hz or 120 Hz, the bass appears to come from the trunk instead of from the front stage. Drop the LP to 80 Hz and the bass moves forward immediately (Car Audio Help).
Slope mismatch between adjacent drivers
Setting the tweeter HP to LR4 (24 dB/oct) and the mid-bass LP to LR2 (12 dB/oct) creates a phase rotation that varies with frequency. The summation at the crossover is no longer flat, and the transition between bands smears. Match slopes on both sides of every crossover.
Setting only the low-pass on the subwoofer
Most DSPs let you set both HP and LP on every channel. On a ported subwoofer you need a high-pass at the box tuning frequency plus 5 Hz to prevent below-tuning unloading damage. Sealed subs can run without a high-pass; ported and bandpass enclosures cannot.
Running the front stage full-range with a sub
Some installers leave the front stage without a high-pass when they add a subwoofer. The mid-bass then plays 30 Hz at high SPL, hits Xmax, distorts, and can damage the coil. A front-stage HP at 60 to 80 Hz keeps the mid-bass alive and lets the sub do the heavy lifting below that point.
Where Crossover Settings Fit in a Full DSP Tune
Crossover settings come early in the tuning process. The order we use on every customer system:
- Polarity check on every channel.
- Crossover frequencies and slopes set per the table above.
- Time alignment.
- Gain structure across the signal chain.
- Level matching channel by channel.
- Parametric EQ.
- Listening passes on reference tracks.
Skip a step and the later ones fight you. We covered the full flow, including SPL targets and EQ strategy, in our complete car audio DSP tuning guide. Once your crossovers are set, the next step is gain structure: matching input and output levels across your head unit, DSP, and amplifiers so you keep headroom without floor noise. Our car audio gain structure guide walks through the procedure. If you're chasing distortion before you tune, how to measure THD in a car audio system is the right starting point.
Watch: Crossover Tuning in Practice
The video below covers the specific frequency and slope choices most car audio installs get wrong, with real DSP examples. Watch it once, then run the table above against your own driver sizes and verify each crossover point against the recommended start frequency.
