Processors & frequency crossovers

Processors & Crossovers at LTT: Your Overview for Professional Sound: Processors and crossovers are the control centre of every serious PA rig — they split, shape and protect your audio signal so each driver plays exactly the frequencies it was built for. At LTT you find active and passive crossovers, digital signal processors (DSP), graphic equalizers and signal splitters for stage, club, theatre and touring use. Whether you run a compact DJ system or a multi-way line array, the right processor turns...

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Processors & Crossovers at LTT: Your Overview for Professional Sound

Processors and crossovers are the control centre of every serious PA rig — they split, shape and protect your audio signal so each driver plays exactly the frequencies it was built for. At LTT you find active and passive crossovers, digital signal processors (DSP), graphic equalizers and signal splitters for stage, club, theatre and touring use. Whether you run a compact DJ system or a multi-way line array, the right processor turns good speakers into a clean, powerful and reliable sound system. As your specialist for event technology, LTT combines hand-picked pro gear with technical know-how so you achieve impressive results at every gig.

What Is a Crossover and How Does It Work? Fundamentals

A crossover (also called a frequency divider) splits a full-range audio signal into separate frequency bands and routes each band to the loudspeaker best suited to reproduce it. The human hearing range spans roughly 20 Hz to 20 kHz — far too wide for a single driver to reproduce cleanly. A crossover therefore feeds low frequencies to the woofer, high frequencies to the tweeter and, in three-way systems, the mid range to a dedicated mid driver.

High-pass, low-pass and band-pass filters

A crossover is essentially a combination of three filter types:

Low-pass filter: lets low frequencies through and blocks the highs. It is realised with coils (inductors), which build up resistance against high frequencies. The low-pass feeds the woofer.
High-pass filter: lets high frequencies through and blocks the lows. It uses capacitors, which resist low frequencies. The high-pass feeds the tweeter.
Band-pass filter: combines a high-pass and a low-pass to pass only a middle range — it feeds the midrange driver.

Resistors are often added for damping and to level-match the drivers to one another. This is why a crossover is more than a splitter: it linearises the frequency response and protects sensitive drivers from energy they cannot handle.

Unlike a simple signal splitter, a crossover makes a frequency-dependent decision. Understanding this distinction is the first step in choosing the right device for your PA system.

Passive vs. Active Crossovers and Digital DSPs: The Comparison

The core difference between crossover technologies lies in where the signal is split and whether the device needs power.

Passive crossovers

A passive crossover uses only capacitors, coils and resistors and needs no external power supply. It sits after the amplifier, directly in front of the drivers — most often built into the loudspeaker cabinet. A single power amp drives the whole speaker, which keeps the setup simple. The trade-off: less flexibility, power lost as heat and no fine-tuning beyond the fixed crossover point.

Active crossovers

An active crossover uses operational amplifiers or transistors and requires power. It splits the signal before amplification, so each band gets its own amplifier channel (bi-amping or tri-amping). This gives you more precision, individual level control per band and easier driver protection.

Digital signal processors (DSP)

A DSP takes active crossovers a step further. Devices such as the dbx DriveRack combine crossover, parametric EQ, time alignment (delay), limiter and room correction in one rack unit. For live sound this means you can align a subwoofer to your tops, protect drivers with precise limiters and store setups as presets. For touring, club and theatre work, DSP-based loudspeaker management is often the optimal solution because it turns a stack of separate boxes into one manageable system.

Criterion	Passive crossover	Active crossover	Digital DSP
Power needed	No	Yes	Yes
Signal split	After amp	Before amp	Before amp
Amps required	One per speaker	One per band	One per band
Flexibility	Fixed	Adjustable levels	Full EQ, delay, limiter
Typical use	Cabinet-internal, DIY	PA, bi-amping	Touring, club, line arrays
Price range	Low	Mid	Mid to high

Types and Variants: Filter Slopes, Crossover Orders and 2-Way vs. 3-Way Systems

Crossovers differ not only in technology but in how sharply they separate frequency bands and how many ways they split.

Filter slopes and orders

The filter slope describes how steeply the level drops beyond the crossover frequency, measured in decibels per octave (dB/oct). Common orders and slopes are:

1st order — 6 dB/oct (gentle, minimal phase shift)
2nd order — 12 dB/oct
3rd order — 18 dB/oct
4th order — 24 dB/oct (steep, best tweeter protection)

Steeper filters keep low-frequency energy away from delicate tweeters more effectively. Two well-known filter alignments are the Butterworth (flat amplitude response) and the Linkwitz-Riley (excellent phase behaviour at the crossover point), the latter often chosen for professional 24 dB/oct designs.

2-way vs. 3-way systems

A 2-way system splits into lows and highs — one crossover frequency. A 3-way system adds a mid band and needs two crossover frequencies, for example around 700 Hz and 4500 Hz. In active operation a stereo 3-way system requires six separate outputs on the processor to drive each driver individually. For subwoofer/satellite operation, a mono subwoofer output sums the lows into a single bass channel — a common and efficient setup for DJs and mobile PA.

Technical Buying Criteria and Features: What the Numbers Mean

When choosing a processor or crossover for professional use, focus on concrete specifications rather than marketing claims.

Output channels: a stereo 3-way active system needs six outputs; count your ways before you buy.
Filter slope: 24 dB/oct (Linkwitz-Riley) is the workhorse standard in PA for reliable tweeter protection.
Crossover frequency range: look for variable frequencies so you can match any driver combination.
Sample rate and bit depth (DSP): high-end digital crossovers offer 48 kHz sampling and up to 64-bit internal processing for clean, low-noise results.
Limiter and delay: essential DSP functions for driver protection and time alignment.
Parametric EQ per channel: several EQ bands on inputs and outputs allow surgical room correction.
Signal-to-noise ratio and gain: a low noise floor matters — a poor processor can become the bottleneck of an otherwise high-quality signal chain.

A quality graphic equalizer, for example, offers 15 or 31 frequency bands per channel (2/3 or 1/3 octave spacing) with switchable gain ranges such as ±6 or ±12 dB. Matching these values to your PA system ensures beautifully controlled results at every event.

Buying Guide: Choosing the Right Processor for PA, Club and Stage

The best processor depends on your application and experience level. Because much online advice targets HiFi or car audio, here is guidance tailored to the live-sound world of DJs, bands, theatres and clubs.

Entry level

For small mobile setups, a passive crossover or a simple analog active crossover with a switchable stereo 2-way / mono 3-way mode is often enough. These are affordable, robust and get you playing quickly.

Mid range

DJs and gigging bands benefit from a compact digital crossover with parametric EQ, delay and limiter — typically in the €200 to €500 range. Software or front-panel control lets you save presets per venue and align your subwoofer to your tops for a tight low end.

Professional

For touring, larger clubs and theatres, a full loudspeaker management processor such as a dbx DriveRack PA2 delivers redundant reliability, precise limiters and the control to manage complex multi-way or line-array systems down to the finest detail.

A quick decision path

Count your ways (2-way, 3-way) and required outputs.
Decide passive, active or DSP based on flexibility needs.
Prioritise limiter functions if driver protection matters — and in live sound it always does.
Match connectors and channel count to your amps and cabling.

Investing in the right processor is one of the most effective ways to make an existing PA sound noticeably better.

Connections, Impedance and System Integration

A processor is only as good as its integration into the wider signal chain. Balanced XLR connectors are the standard in professional use because they reject interference over long cable runs on stage. RCA/Cinch connections are common in HiFi and car audio but rarely used in serious PA work.

When matching amplifiers and speakers, pay attention to impedance: most professional systems run at 4 to 8 Ohm, and your amps must be rated for the load. Make sure your processor provides sufficient output channels for your goal — an active 3-way stereo system requires six outputs so every driver is fed independently.

Integrating into a full PA and effects setup

Because LTT supplies complete event-tech systems, your crossover or DSP rarely works in isolation. It sits between your mixer and your amplifiers, feeding the tops, mids and subwoofers, and it connects through balanced XLR cabling to keep the signal clean. From there the same rig can drive your lighting cues and effect gear on the same stage. Thinking about the whole chain — mixer, processor, amps, speakers and cabling — is how you achieve a reliable, professional result.

Recommended Brands and Manufacturers

LTT stocks high-quality branded products for every budget and application. In the processors and crossovers range you will find these established manufacturers among others:

dbx — the dbx 286S mic preamp/channel strip and the dbx DriveRack PA2 loudspeaker management system are benchmarks for live sound; the dbx 223XS and 234S active crossovers cover 2-way to 4-way operation.
OMNITRONIC — the XO-300 active 3-way crossover with variable 24 dB/oct Linkwitz-Riley filters and the GEQ series graphic equalizers offer excellent value for mobile PA.
IMG Stageline — the MCX-200 electronic crossover for subwoofer/satellite operation and the MEQ-115 graphic equalizer are popular reliable workhorses.
DAP-Audio — digital crossovers such as the DCP-24/DCP-26 combine 48 kHz sampling, parametric EQ, limiter and delay in one unit.
Behringer — devices like the FX2000 Virtualizer round out the signal-processing range.

Each of these brands has earned its place through dependable performance in demanding environments. As your specialist, LTT helps you match the right model to your PA system.

Accessories and Related Categories for Your Signal Chain

A processor or crossover works best when the rest of your signal chain is up to the same standard.

Accessories worth adding

Balanced XLR cabling — the backbone of clean, interference-free connections on stage.
Signal splitters and matrix distributors — such as multi-channel XLR splitter/mixers for feeding several zones or amps from one source.
Rack cases — 19-inch racks keep your processors, EQs and amps protected and transport-ready.
Feedback controllers and line transformer boxes — useful add-ons that solve common problems in fixed installs and mobile rigs.

Related categories

Round out your rig with matching equipment: power amplifiers to drive your speakers, PA loudspeakers and subwoofers to reproduce the split signal, and mixing consoles at the front of the chain. Browse the full LTT sound-technology range to build a coherent, professional system where every component works together for beautifully controlled results.

LTT – Your Specialist for Event Technology

As your specialist for event technology, LTT is more than a shop — with over 25 years of experience and a manufacturing base in Germany, LTT understands what a working PA rig really needs. Every processor and crossover in the range is chosen to deliver dependable performance on stage, in the club and in the touring truck.

Order with confidence: you get free shipping from €69, fast dispatch from Bocholt in Germany, express delivery on request and a 3-year LTT warranty on top. As a reliable partner we also support B2B resellers with wholesale conditions and ship worldwide through our international dealer network.

Complete your setup with matching gear from the wider LTT sound range — power amplifiers, PA speakers and mixing consoles all fit seamlessly into the signal chain you build here. If you are unsure which processor suits your system, our team helps you find the optimal solution.

FAQ – Questions & Answers

A crossover, also called a frequency divider, is a device that splits a full-range audio signal into separate frequency bands and routes each band to the loudspeaker best suited to reproduce it. A crossover feeds low frequencies to the woofer, high frequencies to the tweeter and, in three-way systems, the mid range to a dedicated mid driver. It uses low-pass, high-pass and band-pass filters built from coils, capacitors and resistors. Beyond simply splitting the signal, a crossover linearises the frequency response and protects sensitive drivers from energy they cannot safely handle.

A crossover divides the audio signal by frequency so that each loudspeaker driver only reproduces the range it was designed for. The low-pass section sends bass to the woofer, the high-pass section sends treble to the tweeter, and a band-pass section feeds the midrange in three-way systems. This produces a clean, balanced sound and, just as importantly, protects tweeters and other drivers from damaging low-frequency energy. In active and DSP-based versions, a crossover can additionally adjust levels, apply time alignment and add limiters for driver protection.

You need a crossover whenever a loudspeaker system uses more than one driver type — for example separate woofers, midrange drivers and tweeters. Without a crossover every driver would try to reproduce the full frequency range, causing distortion, poor clarity and premature driver wear. In PA and event use you need an active crossover or DSP as soon as you run a bi-amped or tri-amped system, or a subwoofer/satellite setup where the subwoofer and tops require different frequency bands and individual amplifier channels.

The best crossover depends on your application rather than a single model. For fixed cabinet designs a passive crossover is simple and needs no power. For live PA, DJs and bands a digital signal processor such as a dbx DriveRack is often the optimal solution because it combines crossover, EQ, delay and limiter in one unit. Professional touring and club systems benefit from full loudspeaker management with precise limiters and time alignment. The best choice matches your number of ways, required outputs, driver-protection needs and budget.

A passive crossover uses only capacitors, coils and resistors, needs no power and sits after the amplifier, usually inside the speaker cabinet — one amplifier drives the whole speaker. An active crossover uses operational amplifiers or transistors, requires power and splits the signal before amplification, so each frequency band gets its own amplifier channel. The active crossover offers far more flexibility and precision, including individual level control per band and easier driver protection, which is why active and DSP-based crossovers dominate professional PA and touring systems.

A 2-way crossover splits the signal into two bands — lows and highs — using a single crossover frequency, feeding a woofer and a tweeter. A 3-way crossover adds a midrange band and uses two crossover frequencies, for example around 700 Hz and 4500 Hz, feeding a woofer, a mid driver and a tweeter. In active operation a stereo 3-way system needs six separate processor outputs to drive each driver individually, whereas a stereo 2-way system needs four. Three-way systems generally offer cleaner reproduction across the full range.

Prices for processors and crossovers vary widely by technology and features. Simple passive crossovers and basic analog active crossovers start at the lower end and often stay below €150. Versatile digital signal processors with parametric EQ, delay and limiter typically fall between €200 and €500. Professional loudspeaker management systems for touring and larger venues sit at the top of the range. At LTT you find models across all budgets, with free shipping from €69, fast dispatch from Germany and a 3-year warranty on top.

For a DJ or mobile PA setup, a compact digital crossover or loudspeaker management processor is usually the ideal choice. Devices with a switchable stereo 2-way / mono 3-way mode, parametric EQ, delay and a limiter let you align your subwoofer to your tops and protect your drivers on the fly. Models in the €200 to €500 range, such as DAP-Audio digital crossovers or a dbx DriveRack, offer preset storage per venue and enough outputs for typical DJ rigs. LTT helps you match the right processor to your speaker system.

Processors & Crossovers at LTT: Your Overview for Professional Sound

What Is a Crossover and How Does It Work? Fundamentals

High-pass, low-pass and band-pass filters

A crossover is essentially a combination of three filter types:

Low-pass filter: lets low frequencies through and blocks the highs. It is realised with coils (inductors), which build up resistance against high frequencies. The low-pass feeds the woofer.
High-pass filter: lets high frequencies through and blocks the lows. It uses capacitors, which resist low frequencies. The high-pass feeds the tweeter.
Band-pass filter: combines a high-pass and a low-pass to pass only a middle range — it feeds the midrange driver.

Unlike a simple signal splitter, a crossover makes a frequency-dependent decision. Understanding this distinction is the first step in choosing the right device for your PA system.