Replacing worn factory speakers does not have to become an expensive audio project. A cheap car speaker can restore clarity and add useful volume, but the right choice still depends on size, mounting depth, power handling, and the kind of sound you want.
My first choice is BOSS Audio Systems CH6530 6.5 Inch Car Speakers. Its 4-ohm impedance, 90 dB sensitivity, rubber surround, and 100 Hz to 18 kHz response make it a practical replacement for many factory door locations.
My second choice is PIONEER F-Series TS-F1634R 6.5″ 2-Way Coaxial Car Speakers 200W Max. The 25-watt nominal rating, 4-ohm impedance, 88 dB sensitivity, and standard 6.5-inch size make it a sensible match for many factory stereos.
My third choice is Skar Audio TX4 4″ 120W 2-Way Elite Coaxial Car Speakers. Skar Audio TX4 4 120W 2-Way Elite Coaxial Car Speakers earns my third spot because its compact 4-inch format, fiberglass cone, TPE surround, and copper voice coil suit smaller factory openings. It is especially interesting when a vehicle cannot accept a larger 6.5-inch speaker, although the limited published specifications mean fitment deserves extra attention.
This guide compares all seven options, explains what their specifications mean in everyday driving, and covers sizing, wiring, power, installation, tuning, maintenance, and common mistakes. The goal is to help a first-time buyer choose a practical replacement instead of relying on a large wattage number alone.
7 Cheap Car Speaker Comparison
I selected these products for their relevance to affordable vehicle audio, the amount of useful product information supplied, customer-feedback evidence when available, and practical variety across 4-inch, 5-inch, and 6.5-inch formats. Brand diversity also matters here, so the list includes established names alongside less familiar options that may suit a specific fitment or budget.
| # | Image | Product | Price on Amazon |
|---|---|---|---|
| 1 |  |
BOSS Audio Systems CH6530 6.5 Inch Car Speakers | Price on Amazon |
| 2 |  |
PIONEER F-Series TS-F1634R 6.5″ 2-Way Coaxial Car Speakers 200W Max | Price on Amazon |
| 3 |  |
Skar Audio TX4 4″ 120W 2-Way Elite Coaxial Car Speakers | Price on Amazon |
| 4 |  |
CLES ZYZ 6.5 Inch Coaxial Car Speakers | Price on Amazon |
| 5 |  |
DriSentri 5 Inch Bass Loudspeaker Woofer Speaker | Price on Amazon |
| 6 |  |
DriSentri 6.5 Inch 600W 2-Way Coaxial Car Audio Loudspeaker | Price on Amazon |
| 7 |  |
ePathChina 4 Inch 100W Universal Car Hifi Coaxial Speakers | Price on Amazon |
BOSS Audio Systems CH6530 6.5 Inch Car Speakers
The CH6530 is a strong all-around candidate for replacing factory 6.5-inch speakers. Its three-way layout is intended to separate different parts of the frequency range, while the poly injection cone and rubber surround provide a sensible combination of stiffness and flexibility for ordinary daily use. The stated 100 Hz to 18 kHz response suggests useful vocal and treble coverage, but buyers should not expect deep subwoofer-level bass from a standard door speaker.
With 90 dB sensitivity, this pair should be relatively easy for a factory head unit to drive at normal listening levels. The 4-ohm impedance also fits the common impedance used by many aftermarket and factory car audio systems. Its listed 300-watt figure is a maximum specification, not a guarantee that a factory stereo will deliver that much continuous power.
The physical information is particularly helpful: the pair measures 6.6 by 6.6 by 2.4 inches, with a 2.1-inch mounting depth and a 5.5-inch mounting hole. That makes measuring the existing opening essential, even though 6.5-inch is a common category. The stamped basket keeps the construction practical and lightweight at 1.3 pounds per pair.
Pros
- Three-way design with 90 dB sensitivity.
- Useful mounting depth and hole measurements are provided.
- 4-ohm impedance suits many standard car audio systems.
- Large amount of customer feedback with a 4.3 rating from 17,745 ratings.
Cons
- 100 Hz lower response limit will not replace a dedicated subwoofer.
- Maximum wattage should not be confused with continuous power handling.
- Vehicle-specific brackets or wiring adapters may still be needed.
My Opinion
This is the safest general recommendation in the group for a buyer seeking a straightforward 6.5-inch upgrade. I would choose it when the mounting measurements match and the goal is clearer, fuller everyday sound rather than competition-level bass.
PIONEER F-Series TS-F1634R 6.5″ 2-Way Coaxial Car Speakers 200W Max
Pioneer takes a simpler approach with this two-way coaxial pair. A woofer and integrated tweeter share one speaker assembly, which keeps installation and system design uncomplicated. That arrangement is well suited to replacing a basic factory speaker without adding separate tweeters or changing the rest of the audio system.
The important power distinction is the 200-watt maximum figure versus the listed 25-watt nominal handling. For a factory radio, the nominal number is the more useful reference because factory systems generally produce far less power than large aftermarket amplifiers. The 4-ohm impedance and 88 dB sensitivity are also appropriate for many standard installations, although this pair may not play quite as easily as the more sensitive BOSS option.
At 6.5 inches, the F-Series model fits a common vehicle speaker category, but “standard” does not mean universal. Door depth, mounting tabs, grille clearance, and the factory connector can vary by year, trim, and location. Its black finish should blend into most interiors, but the supplied information does not include a mounting-depth measurement, so that detail should be confirmed before ordering.
Pros
- Recognizable Pioneer branding and a simple two-way coaxial layout.
- 25-watt nominal handling is a reasonable match for many factory stereos.
- 4-ohm impedance and standard 6.5-inch diameter support broad usability.
- 4.4 rating from 9,781 customer ratings provides substantial feedback evidence.
Cons
- Mounting depth is not specified in the supplied information.
- 88 dB sensitivity is moderate rather than especially high.
- Vehicle adapters may be required despite the common speaker diameter.
My Opinion
This is a good alternative for buyers who prioritize a familiar brand and uncomplicated coaxial construction. It ranks behind the BOSS pair mainly because the published fitment details are less complete and the sensitivity is slightly lower.
Skar Audio TX4 4″ 120W 2-Way Elite Coaxial Car Speakers
The Skar Audio TX4 is the most appealing option here for a vehicle with small factory speaker openings. Its 4-inch size avoids forcing a larger speaker into a location that was never designed for it, and the two-way coaxial format keeps the tweeter integrated with the main driver. That makes it a logical replacement for compact dash, door, or rear-panel positions when the original opening is genuinely 4 inches.
The pair is listed at 60 watts RMS, while the product name references 120 watts. For buyers, the RMS figure is the more useful way to think about everyday power because it describes the lower, continuous rating supplied in the data. A 1.25-inch copper voice coil can support the driver’s operation, while the TPE surround is intended to allow controlled movement and resist ordinary environmental wear.
The fiberglass cone is another reason this model stands apart from basic paper-cone replacements. It may appeal to listeners who want a compact speaker with a more purposeful build, but the supplied specifications do not state impedance, sensitivity, frequency response, mounting depth, or hole dimensions. Those omissions make this a product to match carefully rather than buy on size alone.
Pros
- Compact 4-inch format for smaller factory locations.
- Two-way coaxial layout keeps installation relatively simple.
- Fiberglass cone, TPE surround, and 1.25-inch copper voice coil.
- 4.5 rating from 562 customer ratings.
Cons
- Published fitment information is limited.
- Impedance, sensitivity, and frequency range are not supplied here.
- Small cone area will not produce the same low-end presence as a 6.5-inch speaker.
My Opinion
The TX4 is a targeted choice, not the universal winner. I would consider it when a vehicle requires a 4-inch replacement and the seller confirms the missing measurements, but I would not choose it for a 6.5-inch opening or for someone seeking strong bass.
CLES ZYZ 6.5 Inch Coaxial Car Speakers
This CLES ZYZ pair focuses on a high stated power capacity and an easy-installation message. The supplied specifications list 250 watts RMS, 1000 watts peak, 4-ohm impedance, and a 62 Hz to 20 kHz frequency response. If those figures match the actual system and amplifier, the pair could suit a buyer looking for a more energetic 6.5-inch replacement, but a factory radio will not usually deliver anything close to the maximum numbers.
A 13 mm Mylar dome tweeter is paired with a glass-fiber woven woofer. In practical terms, that combination is intended to keep vocals and treble clear while giving the lower midrange more authority than a tiny full-range driver. The high-temperature rubber surround may also be useful in vehicles exposed to seasonal heat and cold. These material claims describe intended construction benefits, not a guarantee against every form of damage.
The product emphasizes solder-free terminals, polarity markings, and a possible 15-minute installation. Actual time depends on the vehicle, access to the speaker, and whether adapter brackets or harnesses are necessary. Fitment still needs to be checked for factory size and mounting depth. There is also an identification detail worth noticing: the packaging may retain a ZYZCLES logo, while the supplied data identifies the product brand as CLES ZYZ rather than the original ZYZCLE.
Pros
- 6.5-inch coaxial format with stated 250-watt RMS handling.
- 4-ohm impedance and broad 62 Hz to 20 kHz frequency range.
- Mylar tweeter, glass-fiber woofer, and rubber surround.
- Polarity markings and solder-free terminals may simplify wiring.
Cons
- Large peak wattage can be misleading without a suitable amplifier.
- Vehicle fitment and mounting depth still require verification.
- Packaging branding may differ from the CLES ZYZ name.
- Only 138 customer ratings are supplied, so the feedback pool is smaller.
My Opinion
This pair is worth considering when its measurements match and an owner wants substantial stated power handling. I would treat the installation and wattage claims conservatively, verify every fitment detail, and avoid paying for amplifier-oriented capacity if the factory radio is staying in place.
DriSentri 5 Inch Bass Loudspeaker Woofer Speaker
The DriSentri 5-inch unit is different from most of the other choices because it is presented primarily as a bass loudspeaker or woofer rather than a conventional full-range door replacement. That makes it potentially useful for a custom car-audio project, a compact enclosure, or a mixed car and home-theater setup. It is not automatically the right substitute for a factory coaxial speaker because the supplied data does not identify a built-in tweeter.
Its wave-shaped butyl synthetic rubber surround is intended to provide flexible movement and support bass response. The metal frame is described as high-strength and electroplated, while the streamlined spider is meant to control cone movement and withstand repeated operation. Those construction details may appeal to someone building around low-frequency performance, but they do not tell a buyer how the driver will behave in a particular vehicle door.
Important electrical information is missing from the supplied data. There is no stated impedance, RMS power rating, sensitivity, frequency range, or mounting depth. The pure copper tinned terminals should help with conductivity and corrosion resistance, yet the terminals alone cannot solve a mismatch between the speaker and an amplifier. Before buying, confirm the enclosure requirements and crossover plan, especially if this woofer will share a system with separate tweeters.
Pros
- 5-inch woofer format for compact custom audio projects.
- Butyl rubber surround and controlled spider design support bass-focused use.
- Metal frame and tinned copper terminals are practical construction choices.
- Can be considered for car audio or home-theater applications.
Cons
- Key electrical and fitment specifications are not supplied.
- It may not provide full-range sound without a separate high-frequency driver.
- Less suitable as a simple plug-in replacement for a factory coaxial speaker.
- Customer feedback is limited to a 3.8 rating from 104 ratings.
My Opinion
This is the most specialized product in the lineup. It makes sense for a buyer who understands custom speaker matching and wants a compact bass driver, but it is a risky choice for a first-time replacement without confirmed electrical and physical specifications.
DriSentri 6.5 Inch 600W 2-Way Coaxial Car Audio Loudspeaker
DriSentri’s 6.5-inch coaxial speaker aims at buyers who want a broad full-range replacement with a high stated output figure. The listed 60 Hz to 20 kHz range covers more of the audible spectrum than the BOSS pair’s published lower limit, while the integrated two-way arrangement keeps the tweeter and woofer in one assembly. That should make it more suitable for ordinary door replacement than the separate DriSentri woofer.
The supplied data lists 4-ohm impedance, 93 dB audio sensitivity, and 12-volt operation. High sensitivity can be useful with a factory stereo because the speaker may reach a given listening level with less electrical power than a less-sensitive design. The 600-watt output figure needs more caution: the data does not identify whether it is peak or continuous, so it should not be used alone to size an amplifier.
A metal and magnet construction is described as rust-resistant, sturdy, and durable, with heat dissipation and stable performance also claimed. Those are useful intentions for a vehicle environment, but the actual fit still depends on the door opening, depth, grille, and factory connector. The product is described as easy to install and broadly compatible with car sound systems, yet “universal” should never replace a physical measurement before purchase.
Pros
- 6.5-inch two-way coaxial design for common door locations.
- 93 dB sensitivity and 4-ohm impedance are useful for factory systems.
- Listed 60 Hz to 20 kHz frequency range.
- Metal construction and a 4.0 rating from 82 customer ratings.
Cons
- The 600-watt figure is not clearly identified as RMS or peak.
- Mounting depth and cutout dimensions are not supplied.
- Some vehicles may need brackets, harnesses, or grille changes.
My Opinion
This is a reasonable value-oriented option when sensitivity and a wide stated range matter more than brand familiarity. Its unclear power terminology and incomplete physical measurements keep it below the better-documented 6.5-inch choices.
ePathChina 4 Inch 100W Universal Car Hifi Coaxial Speakers
The ePathChina pair is built for the smaller end of the car-speaker market. Its 4-inch two-way coaxial format combines a main driver and integrated tweeter, giving a compact factory location access to separate low- and high-frequency elements without a complicated system upgrade. It is a practical candidate for small doors, dashboards, or rear panels, provided the original cutout and depth match.
The power figures are more clearly separated than on several products here: 100 watts maximum and 50 watts RMS. The RMS number is the more useful reference for normal system planning. With 4-ohm impedance and 87 dB sensitivity, the speaker should work with many 12-volt vehicle systems, although a factory radio may not make it as lively as a higher-sensitivity alternative at the same volume setting.
A 47 mm mounting depth is supplied, which is valuable because shallow locations can reject otherwise suitable speakers. The metal frame, high-performance magnet, rubber surround, copper wire terminals, and symmetrical connectors support a straightforward installation. Still, “universal” only means broadly intended for many vehicles; it does not confirm the hole pattern, grille clearance, or connector for a particular car.
Pros
- Compact 4-inch two-way coaxial design.
- 50-watt RMS and 100-watt maximum ratings are clearly stated.
- 47 mm mounting depth helps with shallow-location planning.
- 4.2 rating from 52 customer ratings.
Cons
- 87 dB sensitivity is modest.
- Small 4-inch drivers will have limited deep-bass output.
- Vehicle cutout and connector compatibility still need checking.
My Opinion
This is a sensible compact replacement when the 47 mm depth and 4-inch opening are confirmed. I would select it for clean, balanced improvement in a small location, not as a solution for someone hoping to create powerful low bass.
How I Selected These Budget Car Audio Options
For this cheap car speaker comparison, I weighed each product’s fitment information, speaker layout, power terminology, sensitivity, frequency details, construction, and likely use case. I also considered customer-feedback volume and rating where supplied, while recognizing that online ratings cannot replace vehicle-specific measurements or hands-on installation. The final order favors broadly useful, better-documented choices first, then moves toward compact, specialized, or less fully specified products.
The most important selection lesson: a high maximum-wattage number does not automatically mean louder or better sound in a factory vehicle. Sensitivity, impedance, physical fit, and the stereo’s actual power are often more important.
Why the list includes different sizes
Most shoppers begin with 6.5-inch options because that size is common in vehicle doors, which is why the BOSS, Pioneer, CLES ZYZ, and DriSentri coaxial models receive significant attention. The Skar Audio and ePathChina products remain useful because many vehicles use smaller openings. The DriSentri woofer is included for custom bass-focused projects, but its different role is clearly identified rather than treated as a universal factory replacement.
How customer feedback was used
Customer-feedback volume adds context, especially for the BOSS and Pioneer models, which have thousands of supplied ratings. Smaller feedback pools can still identify an interesting product, but they provide less evidence about long-term consistency across different vehicles. Ratings were therefore treated as one selection signal rather than proof that a speaker will fit every car or sound identical in every installation.
Before ordering, use the ranking as a starting point, then confirm the original speaker’s diameter, mounting depth, hole pattern, connector, and grille clearance. A well-fitting modest speaker is usually a better purchase than a more powerful model that needs improvisation.
How to Choose Budget Car Speakers
Choosing a cheap car speaker is mainly an exercise in matching the speaker to the vehicle and the existing audio system. Start with the physical opening, then compare RMS power, impedance, sensitivity, frequency role, and installation needs. The best value is the model that works comfortably with the equipment already in the car.
- Match the diameter, mounting depth, hole pattern, and grille clearance.
- Use RMS power rather than maximum or peak power for system planning.
- Confirm impedance before connecting a replacement to the factory radio.
- Prefer higher sensitivity when using a low-powered factory head unit.
- Decide whether you need full-range sound, a coaxial replacement, or a bass-only driver.
Match the speaker size and depth
A 6.5-inch label describes the general driver diameter, not every external measurement. Two speakers in the same category can have different mounting tabs, basket shapes, hole patterns, and depths. Measure the existing speaker or consult a vehicle-specific fitment guide, then compare those measurements with the product information. Pay special attention to window glass and door mechanisms behind the mounting surface.
Understand RMS, maximum, and peak ratings
RMS is generally the most useful figure for estimating how much continuous power a speaker can handle. Maximum or peak numbers describe short-duration capacity and can look much larger than the practical rating. The Pioneer pair, for example, lists 200 watts maximum but 25 watts nominal, while the CLES ZYZ pair lists 250 watts RMS and 1000 watts peak. Those numbers should not be compared as if they describe the same measurement.
Use sensitivity and impedance together
Sensitivity indicates how efficiently a speaker turns available electrical power into sound, while impedance describes the electrical load presented to the amplifier or radio. A higher-sensitivity speaker can be a useful match for a factory head unit with limited output. Impedance must still match what the system supports. Do not assume that connecting a lower-impedance speaker will create a free volume increase; it may overwork equipment that was not built for that load.
Choose coaxial, component, or woofer duty
A coaxial speaker places the tweeter and main driver together, making it convenient for a direct replacement. A component system separates drivers and can offer more placement flexibility, but it usually requires more planning. A woofer, such as the 5-inch DriSentri option, focuses on lower frequencies and may need a separate tweeter, crossover, or enclosure. Identify the role of the original speaker before choosing based only on size.
Check Vehicle Compatibility Before Ordering
Vehicle fitment varies by year, make, model, trim, and speaker location. Even two cars from the same manufacturer may use different front-door, rear-door, dash, or rear-deck dimensions. Confirm the exact location being replaced rather than assuming every speaker in the car uses the same size.
Measure the opening
Remove the grille or factory speaker if access is safe and practical. Record the cutout diameter, screw spacing, overall basket width, and depth behind the mounting surface. Check whether the replacement’s tweeter or grille rises higher than the factory unit. A mounting adapter can solve some hole-pattern issues, but it cannot always solve interference with glass or internal bracing.
Check connectors and polarity
Factory plugs may not connect directly to an aftermarket speaker. A vehicle-specific harness adapter can avoid cutting the original wiring and makes future replacement easier. If wires must be connected manually, identify positive and negative terminals carefully. Reversed polarity on one speaker can weaken bass and make the stereo image feel spread out or hollow.
Installation Basics for First-Time Buyers
Disconnect the vehicle battery before working around speaker wiring, especially if the speaker is near an airbag module or other sensitive equipment. Keep screws, clips, and weather seals organized because door panels often use several different fastener types. Read the speaker instructions before removing anything.
Make a clean mechanical connection
The speaker should sit firmly against its adapter or mounting surface without rocking. A loose basket can create buzzing that sounds like a defective driver. Use the correct screws and avoid overtightening, which can warp a frame or strip plastic mounting points. If the vehicle location is exposed to moisture, preserve the factory moisture barrier and do not block drain paths.
Test before reinstalling the panel
Reconnect the speaker temporarily and play a familiar track at low volume. Check for sound, distortion, rattling, and correct left-right balance before replacing the door panel. Test the window and door handle afterward if the speaker was installed in a door. This simple check can prevent removing the panel a second time.
Improve Sound From a Factory Stereo
A replacement speaker cannot overcome every weakness in the factory head unit. Begin with a flat or moderate equalizer setting, then raise volume gradually. Excessive bass boost can force a small speaker to move beyond its comfortable range, causing distortion even when the speaker’s published power rating looks large.
Keep the balance and fader centered while checking the system, then adjust them for the driver’s seat if preferred. If the front speakers sound thin after installation, verify polarity before increasing bass. When adding an amplifier, set its gain to match the radio’s signal rather than treating the gain control as a second volume knob.
Maintenance and Ownership Tips
Car speakers usually need little routine care, but the environment inside a door can be harsh. Avoid spraying cleaner directly through a grille or onto the cone. Use a soft, dry brush or lightly damp cloth on the visible grille, and keep liquids away from terminals and wiring.
Watch for changes such as buzzing, intermittent sound, crackling, or a sudden loss of bass. These symptoms may come from a loose screw, damaged wiring, a failing connector, water exposure, or an amplifier being driven too hard. Addressing the cause early can prevent damage to a replacement speaker.
Protect the surrounding installation
Keep door-panel clips secure and replace missing fasteners instead of allowing the panel to vibrate. Make sure wires cannot touch the cone or window mechanism. If cargo is carried near rear speakers, use the factory grille or another suitable guard to reduce the chance of puncturing the cone or surround.
Troubleshooting New Speaker Problems
If the new speaker produces no sound, first check the connector, polarity, fuse, balance, and fader settings. A loose adapter harness is a common cause of silence after an otherwise successful installation. Test one channel at a time with the volume low so a wiring error does not damage the system.
When there is distortion
Distortion at modest volume can indicate a loose mounting surface, damaged wiring, an incorrect connection, or a source problem rather than a failed speaker. Distortion only at high volume may mean the factory radio or amplifier is clipping, or the equalizer is demanding more bass than the driver can produce. Reduce boost and check the installation before replacing the speaker.
When bass disappears
Weak bass after replacing one speaker often points to reversed polarity or an air leak around the mounting surface. Compare the new speaker with the untouched side at low volume. If one side moves opposite to the other, correct the wiring. A door speaker also depends on the door cavity and moisture barrier, so missing seals can reduce low-frequency output.
Common Mistakes to Avoid
Most disappointing upgrades result from an avoidable mismatch rather than an inherently poor speaker. Slow down before ordering and avoid treating marketing language as a substitute for measurements.
- Do not buy by diameter alone without checking depth and mounting holes.
- Do not compare maximum wattage from one product with RMS wattage from another.
- Do not assume a “universal” speaker includes the correct vehicle harness.
- Do not remove or puncture a door’s moisture barrier during installation.
- Do not raise bass boost to compensate for a speaker that is too small for the desired output.
- Do not connect a speaker with an unsupported impedance to a factory amplifier.
Important caution: never force a speaker into place or allow its basket, magnet, or wiring to contact a moving window mechanism. Confirm clearance before tightening every screw.
FAQS About Cheap Car Speaker
Is a 6.5-inch speaker better than a 4-inch car speaker?
Not automatically. A 6.5-inch driver generally has more cone area and may offer stronger midbass, but a 4-inch speaker is the better choice when the vehicle has a small opening. Installing the correct size is more important than choosing the larger category.
Can factory car stereos power these speakers?
Many of these coaxial models use 4-ohm impedance and can be considered for factory systems, but the radio’s actual output is usually much lower than the maximum wattage printed on the speaker. Higher sensitivity can help a speaker sound louder from limited power. Check the vehicle system before connecting anything with an unusual impedance.
What does RMS mean on a car speaker?
RMS is the useful continuous power-handling reference supplied for normal system planning. Maximum or peak power is a higher short-duration figure and should not be treated as the amount of power a factory radio will deliver continuously.
Do replacement car speakers need an amplifier?
No. A compatible replacement can work from the factory radio, particularly when its impedance and sensitivity suit that system. An amplifier may be useful for higher output, but it also requires correct gain adjustment, wiring, and power planning.
How do I know whether a speaker will fit my vehicle?
Confirm the original speaker’s diameter, mounting depth, screw or tab pattern, connector, and grille clearance. Check the exact vehicle year, make, model, trim, and speaker location. A 6.5-inch or 4-inch label alone does not guarantee direct installation.
Can a woofer replace a factory coaxial speaker?
Usually not as a complete one-for-one replacement. A woofer may focus on bass and lack an integrated tweeter, so it can require separate high-frequency drivers, a crossover, or a suitable enclosure. Confirm the woofer’s electrical and physical specifications before using it in a factory location.
Final Thoughts
For most buyers, the BOSS Audio Systems CH6530 is the strongest overall starting point because its 6.5-inch format and published fitment details are useful. The Pioneer F-Series TS-F1634R is a dependable second choice for a simple branded coaxial upgrade, while the Skar Audio TX4 is the better targeted option for a confirmed 4-inch opening. Choose the cheap car speaker that matches the vehicle and stereo, not merely the one with the largest wattage number.