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Design a sealed or ported enclosure for one to four subwoofers. Explore 3D views and panel cuts.
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BASSHEAD NEMO · BOX BUILDER FOR WINDOWS
We Like
Changing Things Up.
Different subs. Different amps. Different setups. That's part of what makes car audio fun.
We shouldn't have to pay someone else every time we want to try something new. BHN Box Builder gives enthusiasts more freedom to experiment and design their own builds.
BUILD YOUR KNOWLEDGE
Good tools. Zero cost.
Plan your enclosure, work out your wiring, and learn at your own pace.
Wiring Guide
Choose your voice coils and final load, then follow the connections.
Explore Wiring →Encyclopedia
Car audio explained, one term at a time. Pick a letter from A to Z.
Browse A–Z →Ready for the workshop?
Explore tools, job guides, and starter kits.
NEMO’S PERSONAL DEMO VAN · BUILD IN PROGRESS
Loud. Clear. Musical.
A system built around headroom, efficient output, and room to grow. Here’s the thinking behind my personal build.
Power in reserve.
Two JP93 bass amplifiers provide headroom to accommodate impedance rise without relying on extremely low wiring loads. The aim is the output I want without pushing the demo system to its limit.
Two sides. Their own supply.
Dual high-output alternators support separate voltage systems: higher voltage for the bass amplifiers and lower voltage for the midrange and highs.
Doors that keep it musical.
Each door is planned around six PRV 6½-inch midranges and two 8-inch midbass speakers. The goal is loud, clear, full sound with efficient use of amplifier power—and more power available when needed.
Low-end with purpose.
The fourth-order enclosure targets about 36 Hz in its ported chamber. Musical low-end is the priority. Its sealed chamber contributes to cone control alongside appropriate filtering and power management.
Built to grow.
Power-cable runs already extend to the rear, with provision to add more runs as the system grows. The wiring layout is designed to be expandable rather than locking the build into its first configuration.
From layout to installation.
Personal build progress, from the workbench to the van.
Have a build in mind?
Explore standard sealed, ported, and basic wall design services. Advanced bandpass designs are not offered through checkout.
THE CAR AUDIO ENCYCLOPEDIA
Find it. Understand it.
Pick a letter. Tap a term for a clear explanation.
A
Electrical fundamentalsVoltage
Electrical potential difference that drives current through a circuit. An amplifier's available output can change with its supply voltage.
Link to this termElectrical fundamentalsCurrent
Flow of electrical charge, measured in amperes. Powerful amplifiers can demand substantial current from the charging system.
Link to this termElectrical fundamentalsResistance
Opposition to current flow. Resistance at a loose connection can cause voltage loss and concentrated heat.
Link to this termElectrical fundamentalsPower
Rate of energy transfer, measured in watts. For DC input, power equals voltage multiplied by current.
In practice
Link to this termAt 14 volts and 100 amps, DC input is 1,400 watts. Speaker output is lower because the amplifier is not 100% efficient.
Electrical fundamentalsEnergy
Total work available over time. Battery energy is commonly expressed in watt-hours.
Link to this termElectrical fundamentalsOhm's law
The relationship V = I × R. Greater current through the same wiring resistance causes greater voltage drop.
In practice
Link to this termA 0.01-ohm connection carrying 100 amps loses 1 volt: 100 × 0.01 = 1.
Electrical fundamentalsJoule heating
Heat produced by current flowing through resistance. Heating follows I²R: doubling current creates four times the heat at the same resistance.
Link to this termElectrical fundamentalsDirect current — DC
Current flowing in one direction. The battery supplies DC power to the amplifier.
Link to this termElectrical fundamentalsAlternating current — AC
Current reversing direction. An amplifier's speaker signal moves the cone back and forth.
Link to this termElectrical fundamentalsConductivity
How readily a material carries current. Copper and aluminum require different conductor areas for comparable resistance.
Link to this termElectrical fundamentalsSeries circuit
Components connected along one current path. Series-connected speaker impedances add together.
In practice
Link to this termTwo nominal 4-ohm coils in series produce a nominal 8-ohm load.
Electrical fundamentalsParallel circuit
Multiple current paths across the same terminals. Parallel-connected speakers reduce the combined impedance.
In practice
Link to this termTwo nominal 4-ohm coils in parallel produce a nominal 2-ohm load.
Electrical behaviorVoltage drop
Voltage lost across wiring or connections while current flows. Test under load to locate restrictive power or ground paths.
In practice
Link to this termIf the battery measures 14.2 V while the amplifier terminals measure 13.2 V at the same moment under load, the supply and return paths together are losing about 1.0 V.
Electrical behaviorCurrent draw
Current consumed at a particular moment. Music, volume, load impedance, and amplifier efficiency influence it.
Link to this termElectrical behaviorElectrical load
Equipment consuming power. Audio shares the charging system with lights, fans, computers, and other vehicle equipment.
Link to this termElectrical behaviorContinuity
An electrical path between two points. A continuity beep alone does not prove a connection can carry high current properly.
Link to this termElectrical behaviorShort circuit
An unintended low-resistance connection. A positive cable touching grounded metal can cause extremely high current.
Link to this termElectrical behaviorOpen circuit
A broken electrical path. A disconnected remote wire can prevent an amplifier from turning on.
Link to this termElectrical behaviorContact resistance
Resistance where conductive surfaces meet. Corrosion, poor crimps, and loose hardware can increase it.
Link to this termElectrical behaviorInternal resistance
Resistance inside a component or battery. Higher battery resistance generally increases voltage sag under load.
Link to this termElectrical behaviorCapacitance
Ability to store electrical charge. A capacitor supports brief demands but does not replace adequate continuous charging capacity.
Link to this termElectrical behaviorInductance
An electrical property associated with magnetic fields that opposes changes in current. Voice-coil inductance affects speaker behavior.
Link to this termElectrical behaviorReactance
Frequency-dependent opposition caused by capacitance or inductance. Speakers therefore do not behave like simple resistors.
Link to this termElectrical behaviorImpedance
Total opposition to AC, including resistance and reactance. A nominal 2-ohm speaker is not exactly 2 ohms at every frequency.
Link to this termAlternators and chargingAlternator
Engine-driven equipment supplying electrical power and charging the battery while the engine runs.
Link to this termAlternators and chargingAlternator amperage rating
Output capability under stated conditions. That current may not be available at every engine speed.
Link to this termAlternators and chargingIdle output
Current available at idle under specified conditions. Important when playing a system while parked.
Link to this termAlternators and chargingHigh-output alternator
An alternator designed for increased electrical output. Idle performance, heat, and vehicle compatibility still matter.
Link to this termAlternators and chargingVoltage regulator
A control adjusting alternator operation to maintain the intended charging voltage.
Link to this termAlternators and chargingExternal regulator
A separate control used with compatible alternators. Its settings must suit the batteries and vehicle electronics.
Link to this termAlternators and chargingSmart charging
Vehicle-controlled charging that varies with operating conditions. Changing voltage is not automatically a charging fault.
Link to this termAlternators and chargingAlternator pulley ratio
Relationship between engine and alternator pulley sizes, determining alternator speed relative to engine speed.
Link to this termAlternators and chargingBelt slip
Loss of grip between belt and pulley. It can reduce charging output and produce noise or heat.
Link to this termAlternators and chargingCharging setpoint
Target charging voltage. Appropriate settings depend on battery chemistry, temperature, and equipment requirements.
Link to this termAlternators and chargingAlternator ripple
AC variation remaining on the DC supply. Excessive ripple can indicate charging-system problems.
Link to this termAlternators and chargingDual-alternator system
Two alternators in one installation. Mounting, regulation, wiring, and belt loading need coordinated design.
Link to this termBattery fundamentalsStarting battery
A battery designed mainly for short, high-current bursts used to start an engine.
Link to this termBattery fundamentalsDeep-cycle battery
A battery designed for repeated discharge and recharge. Required discharge current still determines suitability.
Link to this termBattery fundamentalsReserve capacity
A standardized measure of time supplying a specified current before reaching a defined cutoff voltage.
Link to this termBattery fundamentalsAmp-hour capacity — Ah
Charge capacity under stated conditions. A 100 Ah rating does not establish unlimited high-current capability.
Link to this termBattery fundamentalsWatt-hour capacity — Wh
Stored energy expressed using voltage and amp-hours. Useful when comparing different-voltage battery banks.
Link to this termBattery fundamentalsCold cranking amps — CCA
A standardized cold-weather starting rating. It does not directly measure sustained support for an audio system.
Link to this termBattery fundamentalsState of charge — SOC
How full a battery is relative to its available capacity.
Link to this termBattery fundamentalsState of health — SOH
Battery condition compared with original performance, including capacity loss and resistance changes.
Link to this termBattery fundamentalsDepth of discharge — DOD
Percentage of capacity removed. Using 30% of a full battery's capacity is approximately 30% DOD.
Link to this termBattery fundamentalsCycle life
Discharge-and-charge cycles endured under specified conditions before a defined degradation threshold.
Link to this termBattery fundamentalsBattery internal resistance
Internal opposition that contributes to heating and voltage loss under heavy demand.
Link to this termBattery fundamentalsBattery voltage sag
Drop in terminal voltage under load. Charge level, condition, temperature, and demand influence it.
Link to this termBattery chemistry and lithiumFlooded lead-acid
Battery construction using liquid electrolyte. Maintenance, ventilation, and mounting requirements matter.
Link to this termBattery chemistry and lithiumAGM
Absorbent glass mat lead-acid construction holding electrolyte in glass mats. Follow the specific battery's charging requirements.
Link to this termBattery chemistry and lithiumGel battery
A lead-acid battery with gelled electrolyte. Charging requirements differ from some other lead-acid designs.
Link to this termBattery chemistry and lithiumLiFePO₄
Lithium iron phosphate chemistry. Charging voltage and temperature limits must match the particular battery system.
Link to this termBattery chemistry and lithiumLTO
Lithium titanate battery technology, often used for high-current applications. Cell voltage differs from other lithium technologies.
Link to this termBattery chemistry and lithiumNMC lithium
Lithium chemistry using nickel, manganese, and cobalt in the cathode. Voltage and protection requirements differ from LTO and LiFePO₄.
Link to this termBattery chemistry and lithiumBattery management system — BMS
Electronics monitoring and protecting a battery within specified capabilities, potentially including voltage, temperature, and current limits.
Link to this termBattery chemistry and lithiumCell balancing
Bringing cell charge levels closer together so one cell is less likely to reach a limit before others.
Link to this termBattery chemistry and lithiumCell configuration
Arrangement of series and parallel cells. Series increases voltage; parallel increases capacity and potential current capability.
Link to this termBattery chemistry and lithiumC-rate
Current expressed relative to capacity. For a 100 Ah battery, 1C equals 100 amps.
In practice
Link to this termA 50 Ah battery at a 2C discharge rate supplies 100 amps. Whether it can do so depends on its specified limits.
Battery chemistry and lithiumCharge acceptance
Charging current a battery can accept under particular conditions. It varies with chemistry, temperature, and charge level.
Link to this termBattery chemistry and lithiumLow-temperature charging protection
Protection blocking or limiting charging below permitted temperatures. Limits depend on the specific battery.
Link to this termPower wire and cable sizingAmerican Wire Gauge — AWG
A conductor-size system. Smaller gauge numbers generally indicate thicker conductors.
Link to this termPower wire and cable sizingCross-sectional area
Actual conductor area, often measured in square millimeters. Insulation thickness does not establish conductor size.
Link to this termPower wire and cable sizingOFC wire
Oxygen-free copper wire. Actual conductor area and construction still matter when choosing cable.
Link to this termPower wire and cable sizingCCA wire
Copper-clad aluminum wire. It has greater resistance than an equal-area copper conductor.
Link to this termPower wire and cable sizingTinned copper
Copper coated with tin to improve corrosion resistance, commonly used in marine or moisture-exposed installations.
Link to this termPower wire and cable sizingWelding cable
Flexible cable intended for welding service. Check conductor material, insulation, environment rating, and terminal compatibility for automotive use.
Link to this termPower wire and cable sizingAmpacity
Current a conductor can carry under specified conditions without exceeding its permitted temperature.
Link to this termPower wire and cable sizingCable length
Distance covered by a cable. Greater length increases resistance for the same conductor material and area.
Link to this termPower wire and cable sizingInsulation temperature rating
Temperature limit of wire insulation. Routing near hot equipment affects cable selection.
Link to this termPower wire and cable sizingStrand count
Number of strands in a conductor. More strands can improve flexibility without necessarily increasing current capacity.
Link to this termPower wire and cable sizingPositive power cable
Cable supplying battery-positive power. Routing and circuit protection are central to its installation.
Link to this termPower wire and cable sizingNegative return cable
Cable carrying return current. Resistance and current capacity matter just as they do on the positive path.
Link to this termFuses and protectionFuse
A device opening a circuit under excessive current according to its operating characteristics and ratings.
Link to this termFuses and protectionFuse amperage rating
Specified fuse current rating. Coordinate it with conductor protection and equipment requirements.
Link to this termFuses and protectionTime-current curve
How quickly a fuse operates at different current levels. A fuse does not necessarily open instantly at its printed rating.
Link to this termFuses and protectionInterrupt rating
Maximum fault current a protective device can safely interrupt. Especially relevant for powerful battery banks.
Link to this termFuses and protectionANL fuse
A bolt-down fuse format commonly used for high-current circuits. Actual product ratings determine suitability.
Link to this termFuses and protectionMini-ANL / MIDI fuse
Compact bolt-down fuse formats. Match the exact fuse to its compatible holder and application.
Link to this termFuses and protectionMEGA fuse
A bolt-down high-current fuse format. Check voltage, interrupt, and time-current ratings.
Link to this termFuses and protectionBlade fuse
A plug-in automotive fuse format commonly used for lower-current circuits.
Link to this termFuses and protectionCircuit breaker
A device interrupting excessive current that may be reset. Verify suitability for the automotive DC circuit.
Link to this termFuses and protectionMain battery fuse
Protection near a battery-positive source connection for the cable leaving that source.
Link to this termFuses and protectionBranch-circuit fuse
Protection for an individual downstream cable, such as a smaller amplifier feed.
Link to this termFuses and protectionFuse-holder resistance
Resistance at the holder and connections. Poor contact can cause heating despite a correctly selected fuse.
Link to this termGrounds and electrical upgradesChassis ground
A connection using the vehicle's metal structure as part of the return path.
Link to this termGrounds and electrical upgradesEngine ground
A connection bonding the engine to the battery-negative and vehicle return system.
Link to this termGrounds and electrical upgradesBattery negative connection
Return connection at the battery. Loose or corroded hardware can affect multiple vehicle systems.
Link to this termGrounds and electrical upgradesGround bonding
Connecting conductive structures to provide an effective shared return path.
Link to this termGrounds and electrical upgradesGround loop
Multiple ground paths that can allow unwanted currents and introduce signal noise.
Link to this termGrounds and electrical upgradesGround offset
Voltage difference between supposedly equivalent ground points, potentially interfering with signal transfer.
Link to this termGrounds and electrical upgradesGround distribution block
A junction combining ground cables. The upstream path must carry their combined demand.
Link to this termGrounds and electrical upgradesBig Three upgrade
Upgrading alternator-positive, battery-negative-to-chassis, and engine-to-chassis wiring. It reduces wiring restrictions without increasing alternator output.
In practice
Link to this termLarger cables may reduce voltage loss, but an alternator already at its output limit still cannot provide additional continuous current.
Grounds and electrical upgradesBig Four upgrade
An expanded power/ground upgrade. The name is informal; specify which fourth connection is included.
Link to this termGrounds and electrical upgradesFactory ground strap
An original bonding connection. It may serve vehicle functions beyond audio.
Link to this termGrounds and electrical upgradesGround-point preparation
Making a clean, secure conductive connection using suitable hardware and corrosion protection.
Link to this termGrounds and electrical upgradesGround voltage-drop test
Measuring voltage across the return path under load to locate losses that an unloaded check can miss.
Link to this termConnections and distributionRing terminal
A cable termination with a closed hole that attaches to a bolt or stud.
Link to this termConnections and distributionFerrule
A sleeve crimped over strands for compatible terminals, containing strands and supporting consistent contact.
Link to this termConnections and distributionButt connector
A connector joining two wire ends. Its conductor range and crimp requirements must match the wires.
Link to this termConnections and distributionCrimp connection
A mechanically compressed electrical joint. Matched tooling and terminals are essential.
Link to this termConnections and distributionSolder joint
A connection made with solder. Mechanical support matters in vibrating or moving installations.
Link to this termConnections and distributionHeat-shrink tubing
Insulating tubing contracting when heated. Adhesive-lined versions can help seal out moisture.
Link to this termConnections and distributionBusbar
A conductive bar distributing power or ground across multiple connections.
Link to this termConnections and distributionDistribution block
A junction splitting a larger feed into branches, sometimes with integrated fuses.
Link to this termConnections and distributionBattery terminal
Connection hardware at a battery post or stud. Contact quality affects the connected circuit.
Link to this termConnections and distributionCable reducer
An adapter connecting large cable to a smaller terminal. It does not remove the smaller terminal's limitations.
Link to this termConnections and distributionTerminal torque
Specified tightening force for hardware. Too little or too much can harm the connection.
Link to this termConnections and distributionStrain relief
Support keeping cable movement from stressing a termination.
Link to this termSwitching and accessoriesRelay
An electrically controlled switch operating one circuit through a separate control circuit.
Link to this termSwitching and accessoriesRelay coil
The electromagnetic part that operates relay contacts when energized.
Link to this termSwitching and accessoriesNormally open contact
A relay contact that stays open while the relay is not energized.
Link to this termSwitching and accessoriesNormally closed contact
A relay contact that stays connected while the relay is not energized.
Link to this termSwitching and accessoriesRemote turn-on wire
A control signal telling equipment to switch on, separate from the main amplifier power feed.
Link to this termSwitching and accessoriesAccessory power
A circuit powered in specified accessory operating modes.
Link to this termSwitching and accessoriesIgnition-switched power
Power available in designated ignition states. Exact behavior depends on the vehicle circuit.
Link to this termSwitching and accessoriesBattery isolator
A device separating battery circuits under particular conditions to manage charging and discharge paths.
Link to this termSwitching and accessoriesAutomatic charging relay
A relay joining or separating battery banks according to its charging-detection logic.
Link to this termSwitching and accessoriesDC-to-DC charger
A regulated charger transferring energy between DC systems with a defined charging profile.
Link to this termSwitching and accessoriesCapacitor
An electrical energy-storage component offering brief support determined by capacitance, voltage, and resistance.
Link to this termSwitching and accessoriesSupercapacitor bank
A group of high-capacitance cells. Cell voltage limits and balancing matter when cells are connected in series.
Link to this termAmplifier fundamentalsMonoblock amplifier
An amplifier with one output channel, commonly used for subwoofers.
Link to this termAmplifier fundamentalsTwo-channel amplifier
An amplifier providing two channels for stereo speakers or supported bridged operation.
Link to this termAmplifier fundamentalsFour-channel amplifier
An amplifier providing four channels, often for front/rear speakers or an active front stage.
Link to this termAmplifier fundamentalsMultichannel amplifier
An amplifier containing multiple channels, potentially combining full-range and subwoofer outputs.
Link to this termAmplifier fundamentalsClass A
An output-stage design whose active devices conduct throughout the signal cycle, usually with relatively low efficiency.
Link to this termAmplifier fundamentalsClass AB
An output-stage design improving efficiency over Class A while addressing crossover distortion.
Link to this termAmplifier fundamentalsClass D
An amplifier using a switching output stage. The amplifier class alone does not determine sound quality.
In practice
Link to this termA well-designed Class D amplifier can deliver clean full-range audio. Switching operation does not mean the music signal is inherently digital.
Amplifier fundamentalsAmplifier efficiency
The share of electrical input delivered as output power. Much of the remainder becomes heat.
Link to this termAmplifier fundamentalsAmplifier power supply
Circuitry converting vehicle power to the internal supply required by the amplifier.
Link to this termAmplifier fundamentalsOutput stage
Circuitry delivering the amplified electrical signal to the speaker.
Link to this termAmplifier fundamentalsMinimum load impedance
Lowest permitted load for a specified configuration. Going below it can exceed amplifier limits.
Link to this termAmplifier fundamentalsProtection mode
Operation limited or stopped because equipment detects a fault, excessive temperature, or unsuitable voltage.
Link to this termAmplifier ratings and operationContinuous output power
Output measured under sustained test conditions. Compare voltage, load, distortion, and channel count along with watts.
Link to this termAmplifier ratings and operationPeak power
A maximum or short-duration claim whose meaning depends on the stated test method.
Link to this termAmplifier ratings and operationRMS voltage
Effective value of an AC waveform. For a resistive load, power is V²/R.
Link to this termAmplifier ratings and operationRated test voltage
Supply voltage used for a published output measurement. Different test voltages affect comparisons.
In practice
Link to this termCompare two power ratings at the same supply voltage and load before concluding which amplifier provides more output.
Amplifier ratings and operationTotal harmonic distortion — THD
Harmonic content introduced relative to the intended signal.
Link to this termAmplifier ratings and operationTHD+N
A measurement combining harmonic distortion and noise.
Link to this termAmplifier ratings and operationSignal-to-noise ratio
Relationship between a specified signal level and background noise under stated conditions.
Link to this termAmplifier ratings and operationDamping factor
Ratio relating load impedance to amplifier output impedance. Wiring and speaker behavior also affect the installed system.
Link to this termAmplifier ratings and operationBridging
Combining compatible channels to drive a load with a greater voltage difference.
Link to this termAmplifier ratings and operationStrapping
Linking specifically compatible amplifiers to drive a load together using the manufacturer's configuration.
Link to this termAmplifier ratings and operationInput sensitivity / gain
Adjustment matching the amplifier to source output level. Correct settings help avoid input or output clipping.
In practice
Link to this termChanging the head unit or line-output converter can require resetting gain because the input signal voltage has changed.
Amplifier ratings and operationChannel separation
How well one channel's signal is isolated from another.
Link to this termSpeakers and componentsSubwoofer
A driver intended for low frequencies. Driver, enclosure, power, and placement determine installed performance.
Link to this termSpeakers and componentsMidbass driver
A speaker covering the region between deep bass and midrange, adding impact and body to instruments.
Link to this termSpeakers and componentsMidrange driver
A speaker covering much of the vocal and instrument range.
Link to this termSpeakers and componentsTweeter
A speaker intended for high frequencies.
Link to this termSpeakers and componentsCoaxial speaker
An arrangement placing multiple frequency-producing elements on a shared axis.
Link to this termSpeakers and componentsComponent speaker system
Separate drivers, typically woofers and tweeters, with a crossover arrangement.
Link to this termSpeakers and componentsCompression driver
A driver coupling diaphragm output through a small exit, generally into a horn or waveguide.
Link to this termSpeakers and componentsHorn
An acoustic structure controlling radiation and improving coupling between a driver and surrounding air.
Link to this termSpeakers and componentsCone
The moving diaphragm radiating sound in a conventional cone speaker.
Link to this termSpeakers and componentsSurround
The flexible connection between the cone's outer edge and the basket.
Link to this termSpeakers and componentsSpider
Inner suspension supporting and centering the moving assembly.
Link to this termSpeakers and componentsVoice coil
Wire winding whose interaction with the magnetic field creates force on the moving assembly.
Link to this termDriver construction and limitsSingle voice coil — SVC
A driver with one coil circuit for connection.
Link to this termDriver construction and limitsDual voice coil — DVC
A driver with two coils permitting multiple wiring configurations.
Link to this termDriver construction and limitsBasket
Structural frame supporting the driver's fixed and moving parts.
Link to this termDriver construction and limitsMagnet assembly
Components creating and directing the magnetic field around the voice coil.
Link to this termDriver construction and limitsPole piece
A magnetic-circuit component helping shape the field inside the motor.
Link to this termDriver construction and limitsTop plate
A magnetic-circuit component forming part of the voice-coil gap.
Link to this termDriver construction and limitsVoice-coil former
Structure supporting the coil winding and connecting it to the moving assembly.
Link to this termDriver construction and limitsBL / force factor
Magnetic flux density multiplied by active conductor length, describing motor force per unit current.
Link to this termDriver construction and limitsThermal power handling
Electrical input a driver tolerates thermally under specified conditions.
Link to this termDriver construction and limitsMechanical power handling
Input limited by travel or mechanical stress. It varies with frequency and enclosure.
Link to this termDriver construction and limitsLinear excursion
Cone travel within a defined range of acceptable suspension and motor behavior.
Link to this termDriver construction and limitsMechanical excursion limit
A manufacturer-defined physical travel or damage limit, different from linear excursion.
Link to this termDriver specificationsFs
Free-air resonant frequency. It is an enclosure-model input, not a universal port-tuning target.
Link to this termDriver specificationsQts
Total driver Q at resonance, combining electrical and mechanical effects.
Link to this termDriver specificationsQes
Electrical Q at resonance, describing the contribution of electrical damping.
Link to this termDriver specificationsQms
Mechanical Q at resonance, describing damping from mechanical losses.
Link to this termDriver specificationsVas
Air volume with the same compliance as the suspension. It is not the recommended enclosure volume.
Link to this termDriver specificationsRe
Voice-coil DC resistance, usually different from nominal speaker impedance.
Link to this termDriver specificationsLe
Voice-coil inductance measured under specified conditions.
Link to this termDriver specificationsSd
Effective radiating area of the diaphragm.
Link to this termDriver specificationsXmax
Rated one-way linear excursion limit. Manufacturers may use different methods to establish it.
Link to this termDriver specificationsVd
Linear displacement volume, commonly calculated as Sd × Xmax using consistent units.
Link to this termDriver specificationsMms
Moving mass in the driver model, including the relevant air-load contribution.
Link to this termDriver specificationsCms
Mechanical suspension compliance. Greater compliance means a more easily displaced suspension.
Link to this termEnclosure designsSealed enclosure
An airtight box whose trapped air adds stiffness to the driver's suspension.
Link to this termEnclosure designsBass-reflex enclosure
A box with a tuned vent contributing output and changing driver behavior around tuning.
Link to this termEnclosure designsFourth-order bandpass
A driver between sealed and ported chambers, with sound radiating through the port.
Link to this termEnclosure designsParallel-tuned sixth-order bandpass
A bandpass enclosure whose two chambers each vent outside.
Link to this termEnclosure designsSeries-tuned sixth-order bandpass
A bandpass enclosure where one chamber vents into the other and the second vents outside.
Link to this termEnclosure designsTransmission line
An acoustic passage behind the driver whose dimensions and damping shape its response.
Link to this termEnclosure designsTapered transmission line
A transmission line with changing cross-sectional area along its length.
Link to this termEnclosure designsFolded horn
A horn with a bent passage to fit a longer acoustic path into a smaller package.
Link to this termEnclosure designsTapped horn
A horn coupling a driver to its passage at two locations whose outputs combine.
Link to this termEnclosure designsPassive-radiator enclosure
A box using an unpowered diaphragm for resonant behavior similar to a port.
Link to this termEnclosure designsInfinite baffle
An arrangement separating front and rear sound while providing sufficiently large rear air volume.
Link to this termEnclosure designsAperiodic enclosure
A design using a resistive acoustic vent to change damping and enclosure behavior.
Link to this termBox volume and behaviorGross internal volume
Interior volume before subtracting components and structural displacement.
Link to this termBox volume and behaviorNet internal volume
Usable chamber airspace after subtracting relevant driver, port, brace, and other displacement.
In practice
Link to this termA 4.0 ft³ gross interior minus 0.3 ft³ of drivers, 0.5 ft³ of port, and 0.2 ft³ of bracing leaves 3.0 ft³ net.
Box volume and behaviorDriver displacement
Interior volume physically occupied by the driver.
Link to this termBox volume and behaviorPort displacement
Space excluded from the main chamber by the port passage and its construction.
Link to this termBox volume and behaviorBrace displacement
Volume occupied by internal bracing, which must be included in net-volume calculations.
Link to this termBox volume and behaviorTuning frequency — Fb
Resonant frequency of a bass-reflex enclosure's chamber-and-vent system.
Link to this termBox volume and behaviorSealed-system resonance — Fc
Resonance of a driver installed in a sealed enclosure.
Link to this termBox volume and behaviorSealed-system Q — Qtc
Total Q of the driver and sealed enclosure, influencing response shape and damping.
Link to this termBox volume and behaviorEnclosure leakage
Unintended airflow through joints or gaps that can change enclosure behavior.
Link to this termBox volume and behaviorStanding wave
A stationary interference pattern formed by sound reflections between boundaries.
Link to this termBox volume and behaviorInternal damping
Materials or construction absorbing acoustic energy to control internal resonances.
Link to this termBox volume and behaviorAcoustic compliance
Spring-like behavior of air. Larger enclosed volumes generally add less air stiffness.
Link to this termPorts and tuningSlot port
A rectangular vent often built partly from enclosure walls.
Link to this termPorts and tuningRound port
A circular vent whose area and effective length contribute to tuning.
Link to this termPorts and tuningFlared port
A vent with shaped ends intended to reduce flow separation and turbulence.
Link to this termPorts and tuningKerf-bent port
A curved wooden port made with closely spaced cuts allowing a panel to bend.
Link to this termPorts and tuningPort area
Cross-sectional airflow opening. It affects velocity and the length required for a given tuning.
In practice
Link to this termAn 18-inch-high slot with a 4-inch clear width has 72 square inches of cross-sectional area.
Ports and tuningPhysical port length
Constructed passage length measured along its path, including bends.
Link to this termPorts and tuningEffective port length
Acoustically relevant length, including effects beyond physical port ends.
Link to this termPorts and tuningEnd correction
An adjustment accounting for air movement outside the port openings.
Link to this termPorts and tuningPort air velocity
Air speed through a vent. High velocity can increase noise and losses.
Link to this termPorts and tuningPort compression
Reduced output growth as increasing airflow creates greater losses.
Link to this termPorts and tuningPort chuffing
Audible turbulence noise from the vent, often noticeable during sustained bass.
Link to this termPorts and tuningPort clearance
Space around an opening. Nearby obstacles can restrict airflow and change acoustic behavior.
Link to this termConstruction and materialsMDF
A dense engineered wood product used for enclosures. Moisture exposure and dust control matter.
Link to this termConstruction and materialsBaltic birch plywood
Multi-ply wood valued for structural properties and exposed-edge appearance. Quality and thickness vary by product.
Link to this termConstruction and materialsMaterial thickness
Panel thickness used in structural design and internal-volume calculations.
Link to this termConstruction and materialsBaffle
The panel supporting the mounted speaker.
Link to this termConstruction and materialsDouble baffle
Two layers forming a thicker, stiffer mounting panel and supporting deeper recesses.
Link to this termConstruction and materialsWindow brace
A brace with openings supporting panels while allowing airflow through the box.
Link to this termConstruction and materialsDado joint
A joint fitting a panel edge into a groove in another panel.
Link to this termConstruction and materialsRabbet joint
A joint using an edge recess to locate and support another panel.
Link to this termConstruction and materialsButt joint
A joint where one panel edge meets another panel's face.
Link to this termConstruction and materialsWood adhesive
Glue selected for the materials and conditions. Joint fit and clamping support strength.
Link to this termConstruction and materialsPilot hole
A smaller hole drilled before a screw to guide it and reduce splitting.
Link to this termConstruction and materialsCountersink
A tapered recess allowing a suitable screw head to sit flush or below the surface.
Link to this termCustom fabricationFiberglass enclosure
A composite enclosure that can follow irregular vehicle contours.
Link to this termCustom fabricationResin
The binding material used with reinforcement in composite construction. Handling requirements depend on the resin system.
Link to this termCustom fabricationMold release
A material preventing a composite part from bonding to its mold.
Link to this termCustom fabricationRouter template
A guide controlling repeatable cuts such as speaker openings and windows.
Link to this termCustom fabricationFlush-trim bit
A router bit using a bearing or guide to match an edge to a reference surface.
Link to this termCustom fabricationSpeaker mounting recess
A stepped opening allowing the mounting flange to sit lower in the baffle.
Link to this termCustom fabricationThreaded insert
A fitting providing reusable internal threads in wood or another material.
Link to this termCustom fabricationAcrylic window
A transparent display panel. Thickness, span, mounting, and sealing determine suitability.
Link to this termCustom fabricationPolycarbonate window
A transparent material with different impact resistance, stiffness, and scratch behavior from acrylic.
Link to this termCustom fabricationWindow gasket
A seal between a transparent panel and its mounting surface.
Link to this termCustom fabricationBeauty panel
A finishing panel concealing hardware, structural surfaces, or gaps.
Link to this termCustom fabricationSpeaker grille
A protective cover shielding the driver while allowing sound transmission.
Link to this termSources and signal connectionsHead unit
The audio source and control device supplying signals to the system.
Link to this termSources and signal connectionsRCA preout
A line-level analog output connecting a source to an amplifier or processor.
Link to this termSources and signal connectionsSpeaker-level signal
An amplified speaker signal, sometimes accepted by compatible amplifier or processor inputs.
Link to this termSources and signal connectionsLine-output converter — LOC
A device converting speaker-level signals for use with line-level inputs.
Link to this termSources and signal connectionsBalanced connection
A signal arrangement designed to reject interference common to both signal conductors when properly implemented.
Link to this termSources and signal connectionsDifferential input
An input responding to the voltage difference between conductors, potentially rejecting shared interference.
Link to this termSources and signal connectionsBluetooth audio
Wireless audio whose behavior depends on devices, codec, and implementation.
Link to this termSources and signal connectionsUSB audio
Digital audio transferred using supported USB device protocols.
Link to this termSources and signal connectionsDigital-to-analog converter — DAC
A device converting digital audio data into an analog electrical signal.
Link to this termSources and signal connectionsOptical audio
Digital audio carried by light through fiber, providing electrical isolation between connected devices.
Link to this termSources and signal connectionsSource clipping
Distortion created when the source exceeds its signal range, before the amplifier receives the signal.
Link to this termSources and signal connectionsRemote bass controller
An external level or bass control. Its actual function depends on the amplifier or processor design.
In practice
Link to this termA remote level knob may only reduce output from the gain setting, while a boost knob may increase a particular frequency region. Check its documented function.
Factory-system integrationFactory amplifier
The original vehicle amplifier, potentially including processing, filtering, diagnostics, and multiple outputs.
Link to this termFactory-system integrationFactory equalization
Frequency shaping built into the original system for its speakers and installation.
Link to this termFactory-system integrationFactory crossover
Filtering assigning different frequency ranges to original speakers.
Link to this termFactory-system integrationAll-pass filter
A filter changing phase while ideally preserving magnitude response.
Link to this termFactory-system integrationSignal summing
Combining signals, potentially reconstructing broader frequency coverage from separate factory channels.
Link to this termFactory-system integrationBass roll-off
Reduction of low-frequency output, sometimes increasing with volume in factory systems.
Link to this termFactory-system integrationLoad detection
Monitoring an output's electrical load, potentially changing operation when a speaker is disconnected.
Link to this termFactory-system integrationLoad resistor
A resistor presenting a defined load. Resistance and heat dissipation must match the application.
Link to this termFactory-system integrationData-bus interface
An adapter communicating with vehicle networks to retain or provide supported functions.
Link to this termFactory-system integrationActive noise cancellation — ANC
A vehicle system generating sound to reduce cabin noise. Audio changes can affect its operation.
Link to this termFactory-system integrationFactory chime retention
Preserving alerts and notification sounds when modifying original audio equipment.
Link to this termFactory-system integrationIntegration DSP
A processor accepting, correcting, combining, and routing existing-system signals.
Link to this termDSP and tuningDigital signal processor — DSP
Digital audio processing equipment offering functions such as filters, EQ, delay, and routing.
Link to this termDSP and tuningHigh-pass filter
A filter reducing frequencies below its transition region.
Link to this termDSP and tuningLow-pass filter
A filter reducing frequencies above its transition region.
Link to this termDSP and tuningBand-pass filter
A filter passing a selected frequency range while reducing output above and below it.
Link to this termDSP and tuningInfrasonic filter
A high-pass filter reducing very low frequencies, often used to limit excessive subwoofer excursion.
Link to this termDSP and tuningCrossover slope
Attenuation rate beyond a filter's transition region, commonly expressed in decibels per octave.
Link to this termDSP and tuningButterworth filter
A filter alignment designed for a maximally flat passband magnitude response.
Link to this termDSP and tuningLinkwitz–Riley filter
A crossover alignment designed for a particular summed response when complementary branches are correctly combined.
Link to this termDSP and tuningParametric equalizer
EQ with adjustable frequency, gain, and bandwidth or Q.
Link to this termDSP and tuningGraphic equalizer
EQ using fixed frequency bands with adjustable levels.
Link to this termDSP and tuningTime alignment
Delay applied to selected channels to adjust arrival timing at a listening position.
Link to this termDSP and tuningLimiter
Processing restricting signal level according to configured limits and timing behavior.
Link to this termAcoustics and sound qualityFrequency
Cycles per second, measured in hertz. A 40 Hz tone completes 40 cycles every second.
Link to this termAcoustics and sound qualityWavelength
Distance covered by one wave cycle. Lower frequencies have longer wavelengths.
Link to this termAcoustics and sound qualitySound pressure level — SPL
Sound pressure expressed logarithmically in decibels relative to a reference pressure.
Link to this termAcoustics and sound qualityFrequency response
How system output changes across frequency under specified measurement conditions.
Link to this termAcoustics and sound qualityCabin gain
Low-frequency reinforcement associated with the vehicle interior and its acoustic boundaries.
Link to this termAcoustics and sound qualityPhase
Position of a repeating signal within its cycle relative to another signal.
Link to this termAcoustics and sound qualityPolarity
Electrical orientation of a connection or signal. Reversing polarity inverts the waveform.
Link to this termAcoustics and sound qualityAcoustic cancellation
Reduced output when sound contributions combine destructively because of phase and timing relationships.
Link to this termAcoustics and sound qualitySoundstage
Perceived location and spread of performers or instruments.
Link to this termAcoustics and sound qualityImaging
How precisely a system places perceived sound sources within the soundstage.
Link to this termAcoustics and sound qualityConstrained-layer damping
A treatment combining a damping layer and constraining layer to reduce panel vibration.
Link to this termAcoustics and sound qualityMass-loaded vinyl
A heavy flexible barrier used in suitable sound-isolation assemblies. It serves a different function from panel damping.
Link to this termTesting, troubleshooting, and competitionDigital multimeter
A tool measuring voltage, resistance, and other quantities within its specified capabilities.
Link to this termTesting, troubleshooting, and competitionOscilloscope
A tool showing voltage over time, useful for observing waveforms and clipping.
Link to this termTesting, troubleshooting, and competitionClamp meter
A tool measuring conductor current without opening the circuit, within its AC or DC capabilities.
Link to this termTesting, troubleshooting, and competitionMeasurement microphone
A microphone with known measurement characteristics used to assess acoustic output.
Link to this termTesting, troubleshooting, and competitionImpedance sweep
Measurement of impedance across frequency to investigate driver and enclosure behavior.
Link to this termTesting, troubleshooting, and competitionAmplifier clipping
Waveform distortion caused when an amplifier cannot reproduce the requested signal within its available limits.
Link to this termTesting, troubleshooting, and competitionThermal compression
Reduced output as heating changes driver behavior, commonly through increasing voice-coil resistance.
Link to this termTesting, troubleshooting, and competitionPort unloading
Reduced acoustic loading below a vented enclosure's tuning region, allowing greater cone excursion.
In practice
Link to this termPlaying substantial bass below a ported box’s tuning can demand more cone travel even when the amplifier has not reached its maximum output.
Testing, troubleshooting, and competitionAlternator whine
Noise often changing with engine speed. Signal, grounding, wiring, and charging faults can contribute.
Link to this termTesting, troubleshooting, and competitionParasitic draw
Current consumed while a vehicle is in its intended off or sleep state.
In practice
Link to this termAn amplifier that remains on after the vehicle sleeps can contribute to overnight battery discharge.
Testing, troubleshooting, and competitionSPL competition burp
A brief tone played for high measured output. Frequency and duration depend on the event and system.
Link to this termTesting, troubleshooting, and competitionMicrophone placement
Sensor position and orientation. Consistent placement is essential for comparisons and must follow applicable competition rules.
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Panel cut list
How the panels fit
Square butt joints. Double baffle stays inside the selected outside dimensions; internal depth and port length account for both layers. Front/back panels cap the frame; top/bottom span its full width, and sides fit between them. Dimensions exclude saw kerf. Check driver basket clearance, mounting depth, material, and your vehicle before cutting. Slot ports fold once when needed; kerf folds use a curved channel and matching corner filler. No driver-response or port-air-speed simulation is provided.
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Swipe or scroll the diagram to see every sub and terminal.
Disconnect amplifier power before wiring. Check every terminal and the amplifier’s manual before turning it on. Calculated values are nominal AC impedance; a multimeter measures DC resistance, which is normally lower. The terminal blocks are enlarged on each sub for clarity. Physical terminal positions vary by model; identify the actual coil and polarity labels on your subwoofer.
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About
About Basshead Nemo
My interest in car audio started before I was old enough to drive. It was something my family enjoyed—my brothers always had cars, speakers, amplifiers, and old stereo equipment around. I started by experimenting with equipment they were no longer using, and that gradually developed into an interest in electronics and car audio.
By the time I was getting my first car, the stereo system was already part of the plan. I learned installations hands-on, working on older vehicles and helping with other people's systems before wiring guides and plug-and-play solutions were something I knew about.
I also learned through mistakes. I've dealt with inadequate electrical systems, damaged alternators, amplifier failures, clipping, and blown equipment. Those experiences pushed me to understand not just how to install equipment, but why systems work—or fail—the way they do.
Over the years, I continued building systems and expanding my knowledge. I also realized that even with the amount of car-audio information available today, there is still a need for practical information written for the person actually building and using the system.
I began sharing what I had learned through videos. As those videos reached more people, I started receiving questions and requests for help from others building their own systems.
BASSHEAD NEMO LLC grew naturally from that. What started as a family interest became years of hands-on experience, learning, building, and helping others. I'm now turning that experience into a career and building resources designed to make useful car-audio information easier to understand and apply.
And this is only the beginning.
Business inquiries: [email protected]
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