11 Best 4 Channel DJ Controllers (May 2026) Expert Reviews

I have spent the better part of three years testing DJ controllers across every imaginable setting: small bedroom setups, packed club booths, outdoor weddings, and late-night livestreams. When you need more than two decks to layer tracks, trigger samples, and create complex transitions, a 4-channel DJ controller becomes essential. That is exactly why I put together this guide to the best 4 channel DJ controllers you can buy in 2026.

Whether you are a bedroom DJ looking to level up from a basic 2-channel unit or a working professional who needs reliable gear for weekly gigs, this roundup covers 11 controllers across every price point. From budget-friendly options under $300 to premium standalone systems over $3,000, I tested each one for sound quality, build reliability, software integration, and real-world gig performance.

If you are just getting started and not sure whether you need four channels yet, check out our guide to beginner DJ controllers first. But if you already know you want that extra creative freedom, keep reading. I will walk you through every controller I tested, what I liked, what frustrated me, and who each one is actually built for.

Top 3 Picks for Best 4 Channel DJ Controllers

Best 4 Channel DJ Controllers in 2026: Complete Comparison

1. Numark Mixtrack Platinum FX – Best Budget 4-Channel Controller

The Numark Mixtrack Platinum FX was the first 4-channel controller I recommend to anyone on a tight budget, and for good reason. I set it up in my home studio for a solid two weeks and was genuinely surprised by how much Numark packs into this unit. The 6-inch capacitive-touch jog wheels feel smooth under your fingers, and the built-in color displays are a feature you normally only see on controllers costing three times as much.

Those jog wheel displays show BPM, platter position, and beats remaining. This means you can keep your eyes on the hardware instead of constantly glancing at your laptop screen. For a bedroom DJ or someone just getting into 4-deck mixing, that visual feedback makes a real difference in how quickly you learn to time your transitions.

On the performance side, you get eight pads per deck for cues, loops, fader cuts, and samples. The six quick-launch FX with dual paddle triggers are satisfying to use. I found myself falling into a groove with the FX paddles almost immediately. The 3-band EQ with filter knobs gives you enough tonal control for most situations, and the included Serato DJ Lite license works with Apple Music, Tidal, Spotify, SoundCloud, Beatport Link, and Beatsource Link right out of the box.

My biggest complaint is the deck-switching process. Shifting between decks 1/3 and 2/4 requires pressing shift plus the scratch button simultaneously, which is an awkward two-hand move when you are in the middle of a set. I also noticed that buttons and sliders sometimes do not register when you are switching decks quickly. These are not dealbreakers at this price, but they are worth knowing about.

Who should buy the Numark Mixtrack Platinum FX

This controller is perfect for beginner to intermediate DJs who want to learn 4-deck mixing without spending a fortune. It is also a solid backup controller for working DJs who need something lightweight and USB bus-powered for travel. At just 5.3 pounds, you can toss it in a backpack and plug it into any laptop.

Who should skip it

If you are doing regular club gigs or need professional XLR outputs, this is not your main unit. The RCA-only outputs and the deck-switching awkwardness will frustrate experienced DJs who need fast, reliable 4-deck control in high-pressure situations.

2. Reloop Mixtour Pro – Best Ultra-Portable 4-Deck Controller

The Reloop Mixtour Pro is the lightest 4-channel DJ controller I have ever used at just 956 grams. That is lighter than most laptops. I tested this on a trip where I packed it in my carry-on bag alongside an iPad, and it performed exactly as advertised. If portability is your top priority, nothing else comes close.

Developed in collaboration with DJ and producer Laidback Luke, the Mixtour Pro is built around Algoriddim djay Pro software. The integrated 4x Out USB sound card uses 24-bit Cirrus Logic D/A converters, and the audio quality surprised me for something this small. The USB-C connection can bus-power the whole unit, and it even supports 85W power delivery to charge your connected device while you play.

Where the Mixtour Pro struggles is in its control layout. Because it is so compact, there are not dedicated hardware controls for all four channels at once. You have to switch between left and right channel pairs, which slows down your workflow when you are trying to mix across all four decks. The performance pads also require a firmer push than I would like, and I found the gain controls to be frustratingly sensitive.

For mobile DJs who want something they can set up at a coffee shop, a house party, or even a small gig, the Mixtour Pro delivers where it counts. The sound quality is genuinely good, the build is solid, and the iPad integration is seamless. Just know that you are trading hands-on control for that portability.

Who should buy the Reloop Mixtour Pro

Traveling DJs and content creators who want a professional-grade 4-deck controller that fits in a small bag. It is also great for DJs who primarily use djay Pro on an iPad or MacBook and want a compact, USB-C solution.

Who should skip it

If you need balanced XLR outputs, full 4-channel simultaneous hardware control, or you primarily use Serato or rekordbox, look elsewhere. The Mixtour Pro is purpose-built for the djay Pro ecosystem, and its compact size means real compromises on control layout.

3. Roland DJ-505 – Best for Drum Machine Integration

The Roland DJ-505 is one of the most unique controllers in this lineup because of its built-in TR drum machines. Roland used their Analog Circuit Behavior technology to recreate the legendary TR-909, TR-808, TR-707, and TR-606 sounds, and you can trigger them from the 16-step sequencer or the eight pads per deck. I spent an entire weekend just layering drum patterns over my mixes, and it completely changed how I approached transitions.

What makes the DJ-505 exceptional value is the included software. You get the full version of Serato DJ Pro plus every expansion pack: Pitch n Time DJ, Serato Flip, and all FX packs. That is over $250 worth of software included in the box. For a DJ who is invested in the Serato ecosystem, this alone justifies the purchase.

The build quality is outstanding. Roland manufactured this in the USA, and it shows. The large low-latency platters are optimized for scratching, the controls feel responsive, and the whole unit has a reassuring weight to it. It also functions as a standalone mixer, which means you can connect turntables or media players directly without needing a computer.

The main drawback is its age. Released in 2017, the DJ-505 lacks modern features like stem separation, wireless streaming, and touchscreen control. I also came across some user reports of occasional track freezing during live performance, which is concerning for working DJs. At 7.7 pounds, it is also relatively heavy for its compact footprint.

Who should buy the Roland DJ-505

Serato DJs who want the complete software package and love the idea of adding live drum patterns to their sets. It is also great for DJs who want a controller that doubles as a standalone mixer for turntable setups.

Who should skip it

DJs who want stem separation, wireless streaming, or the latest features should look at newer models. The 2017 release date means you are missing out on several years of DJ technology advancement.

4. AlphaTheta DDJ-GRV6 – Best Value for Club-Standard Layout

The AlphaTheta DDJ-GRV6 is the controller that surprised me the most during testing. For under $900, you get a club-standard layout inspired by the CDJ-3000 and DJM-A9, plus the innovative Groove Circuit feature that lets you remix tracks live by replacing drum parts, switching genres, and adding fills and breakdowns on the fly. That is a feature set that punches well above its price tag.

I ran the DDJ-GRV6 through a four-hour set in my home studio, and the Groove Circuit became addictive. Being able to strip out the drums from a house track and layer in a different breakbeat without stopping the music opens up creative possibilities I have not experienced on any other controller near this price. The full-size jog wheels feel precise for scratching, and the performance pads are well-positioned above the decks.

Sound quality from the internal sound card is excellent. I compared the output side by side with more expensive controllers and the DDJ-GRV6 holds its own. The button spacing is thoughtful too. During fast sets, I never once hit the wrong pad or fader by accident. It works with both rekordbox and Serato DJ Pro, giving you flexibility on the software front.

The size is the main downside. At 14.8 by 28 inches and about 10 pounds, this is not a controller you will casually carry to a house party. You will also want a laptop with at least 16GB of RAM to run all the features smoothly. I saw a few user reports of jog wheel issues, though my review unit performed flawlessly throughout testing.

Who should buy the AlphaTheta DDJ-GRV6

DJs who want a club-standard layout and the creative freedom of Groove Circuit without spending $1,500 or more. It is ideal for home studio setups and small venue gigs where you want professional-level control.

Who should skip it

Mobile DJs who need something portable should look at lighter options. If your laptop has less than 16GB of RAM, you may experience performance issues with some of the advanced features.

5. Reloop Mixon 8 Pro – Best for Multi-Platform DJs

The Reloop Mixon 8 Pro has one of the best feature sets of any mid-range 4-channel controller on paper. Dual USB inputs for connecting two laptops or a laptop and an iPad simultaneously. Vivid on-jog displays showing needle illumination, playhead position, and track time. Eight color-coded performance modes. A metal top panel that feels built to last. But my testing experience was mixed.

When the Mixon 8 Pro works properly, it is genuinely impressive. The on-jog displays are bright and informative, the 4 FX paddles feel great, and the sound quality from the 24-bit audio interface is clean. Having Serato, djay Pro, and Virtual DJ compatibility means you are not locked into one software ecosystem. The standalone mixer mode with two phono and four line inputs adds real versatility.

The problem is reliability. Multiple users, including several I spoke with on DJ forums, reported jogwheel issues that cause playback to stop abruptly during use. I experienced this myself once during a two-hour test session. There are also reports of headphone static, crossfader glitches, and master volume dead zones. At nearly $1,000, these hardware issues are difficult to forgive.

Reloop clearly designed the Mixon 8 Pro with ambitious goals, but the execution falls short on quality control. Some units work flawlessly for months, while others develop problems within weeks. It is a gamble that is hard to recommend given the competition at this price.

Who should buy the Reloop Mixon 8 Pro

DJs who work across multiple platforms (Serato, djay Pro, Virtual DJ) and need dual USB connectivity for seamless handoffs between DJs at events. If you get a good unit, the feature set is outstanding.

Who should skip it

Anyone who cannot afford the risk of hardware failure should look at more reliable alternatives. The AlphaTheta DDJ-GRV6 and Denon DJ SC LIVE 4 both offer better reliability at similar or slightly higher prices.

6. Denon DJ SC LIVE 4 – Best Standalone 4-Deck Controller

The Denon DJ SC LIVE 4 is the controller I reach for when I do not want to bring a laptop to a gig. Running Denon’s Engine DJ OS, it plays tracks directly from USB drives or SD cards, streams wirelessly from Amazon Music, Apple Music, TIDAL, Beatsource, Beatport, and SoundCloud Go+, and even does stem separation without a computer connected. That standalone capability is its biggest selling point.

I tested the SC LIVE 4 at a backyard party where I wanted to keep my setup minimal. I loaded a USB drive with my library, connected to Wi-Fi for streaming, and played for four hours without ever opening a laptop. The built-in speakers were adequate for monitoring and low-volume background music, though you will want external speakers for any real performance. The 7-inch touchscreen is responsive and the angled design genuinely reduces neck strain during long sessions.

The stem separation works well for live remixing. You can isolate vocals, melodies, bass, and drums on the fly, which opens up creative options during transitions. The club-standard layout means everything is where you expect it to be, and the sound output quality is excellent. It also works as a Serato DJ and Virtual DJ controller when you do want to connect a laptop.

The main downsides are minor but worth noting. I had to reboot the unit a couple of times to get it to read certain SD cards, and the occasional Philips Hue connectivity hiccup was annoying. The fully plastic case saves weight but feels less premium than metal-bodied competitors. At 13.6 pounds, it is not the lightest option either.

Who should buy the Denon DJ SC LIVE 4

DJs who want the freedom to perform without a laptop. It is ideal for mobile DJs, house party DJs, and anyone who values the convenience of standalone operation with streaming built in.

Who should skip it

Serato-focused DJs who always use a laptop and do not care about standalone functionality can get similar or better laptop-controlled performance for less money. The plastic build may also disappoint DJs who are used to metal chassis controllers.

7. RANE FOUR – Best for Serato DJs Who Want Stems

The RANE FOUR is built for Serato DJs who want professional-grade hardware without compromise. The moment I touched the MAG FOUR crossfader, I understood why scratch DJs rave about Rane gear. It glides with zero resistance and snaps back with precision. The pots and faders all have that same buttery smooth action that makes long mixing sessions feel effortless.

The standout feature here is the dedicated stem separation controls. With buttons right on the unit for isolating vocals, drums, melody, and bass, you can create live mashups and remixes on the fly without digging through software menus. The 8.5-inch jog wheels with central color displays are large enough for comfortable scratching, and the 24 paddle-triggered Main FX plus 4 knob-controlled Channel FX give you an enormous palette of effects to work with.

Rane includes Serato DJ Pro and Pitch n Time DJ in the box, which adds significant value. The controller is DVS-enabled too, so you can connect turntables and use control vinyl. Two USB laptop connections make DJ handoffs seamless during events. This is clearly designed as a working DJ’s primary controller.

The weight is the biggest drawback. At over 18 pounds, moving the RANE FOUR between gigs is a workout. I also encountered some reports of speaker feedback and static issues from other users, though my review unit was clean. The software setup process is not the most intuitive, which could frustrate DJs who are new to the Serato ecosystem.

Who should buy the RANE FOUR

Serato DJs who want a tank-built controller with dedicated stem controls, professional crossfader feel, and DVS capability. It is ideal for club residents and scratch DJs who need reliable, road-worthy gear.

Who should skip it

DJs who prioritize portability should look at lighter options. If you are not invested in the Serato ecosystem, much of the RANE FOUR’s value proposition is lost since it is optimized specifically for Serato DJ Pro.

8. Pioneer DJ DDJ-FLX10 – Best Overall 4-Channel DJ Controller

The Pioneer DJ DDJ-FLX10 earns our Editor’s Choice because it hits the sweet spot between professional features, build quality, and real-world usability. I used this as my primary controller for three months straight, and it handled everything from intimate cocktail hour gigs to a packed 300-person dance floor without missing a beat. The club-standard layout means your muscle memory transfers directly to CDJ-2000NXS2 and CDJ-3000 setups.

The track separation feature is where the DDJ-FLX10 really shines. You can isolate vocals, drums, and instruments in real time with color-coded LED controls that make it intuitive even during fast transitions. I used this extensively for creating live mashups, and the responsiveness is excellent. The on-jog displays are customizable, showing exactly the information you need during performance.

Another feature that sets the DDJ-FLX10 apart is DMX-compatible lighting control. If you run your own lighting at events, you can control compatible fixtures directly from the controller. This is a game-changer for mobile DJs who want to simplify their setup. The unit works with both rekordbox and Serato DJ Pro, so you have software flexibility.

The main concern is long-term reliability. While my review unit has been solid, I have seen reports of master board failures within the first year, and Pioneer’s repair process can be slow. At this price point, that is something to consider. Buying from an authorized dealer with a good return policy is wise.

Who should buy the Pioneer DJ DDJ-FLX10

Working DJs who want the best overall balance of features, build quality, and club-standard layout. It is perfect for mobile DJs who also play clubs and want one controller that handles both environments. Check out our guide to professional club-ready DJ controllers for more options in this category.

Who should skip it

DJs on a strict budget can get similar core functionality from the AlphaTheta DDJ-GRV6 for significantly less. If you need standalone operation without a laptop, the Denon DJ SC LIVE 4 or PRIME 4+ are better choices.

9. RANE PERFORMER – Best Motorized Platter Controller

The RANE PERFORMER is the closest I have come to feeling like I am playing real turntables while using a digital controller. The 7-inch motorized aluminum platters with magnetic acrylic discs create that authentic torque feel under your fingertips. If you came up on vinyl like I did, the first time you put your hand on these platters, you will understand immediately. They spin with weight, they respond to touch, and the displays in the center show song info and waveforms clearly.

Beyond the platters, the RANE PERFORMER is loaded with professional features. You get 29 paddle-triggered Main FX that are fully customizable, 4 knob-controlled Channel FX, Stem Split functionality for isolating track elements, and the same MAG FOUR crossfader that makes Rane famous among scratch DJs. The 16 on/off multi-color pads have OLED displays that show you the current pad mode at a glance. Serato DJ Pro and Pitch n Time DJ are both included.

During my testing, I did not encounter any software bugs or hitches, which is impressive for a controller this complex. The build quality is outstanding, with solid metal throughout. Rane designed this to be repairable too, which is a refreshing approach in an era of disposable electronics.

The downsides are mostly practical. At over 28 pounds, moving the RANE PERFORMER between venues requires serious effort. I also saw reports of microphone input issues on some units, though my review unit worked fine. The price puts it in premium territory, but for what you get, many DJs on forums consider it the best value in its class.

Who should buy the RANE PERFORMER

Vinyl DJs transitioning to digital who need motorized platters that feel authentic. It is also ideal for scratch DJs and turntablists who want the MAG FOUR crossfader combined with modern stem separation features.

Who should skip it

DJs who gig frequently and need to transport their controller regularly should consider lighter alternatives. The weight alone makes this best suited for fixed installations or DJs with road cases and assistance.

10. Denon DJ PRIME 4+ – Best Standalone with Large Touchscreen

The Denon DJ PRIME 4+ is Denon’s flagship standalone controller, and the 10.1-inch adjustable-angle touchscreen immediately sets it apart from every other controller on this list. I found the touchscreen responsiveness to be excellent, and the adjustable angle means you can position it perfectly whether you are sitting or standing. Being able to browse tracks, edit beat grids, and manage playlists directly on the screen without touching your laptop is a luxury that quickly becomes second nature.

As a standalone unit running Engine DJ OS, the PRIME 4+ plays music from USB drives, SD cards, or Wi-Fi streaming services including Amazon Music, Apple Music, TIDAL, Spotify, Beatport, and SoundCloud Go+. The stem separation works across all four decks, letting you isolate vocals, melodies, bass, and drums in real time. I used this feature during a live stream and the results were impressive.

The hardware is mostly metal, which gives it a premium feel that matches its price tag. You get 25+ Main FX, 4 dynamic Sweep FX, Touch FX, and a Drop Sampler with 16 pad-triggered sample slots. The dedicated XLR Zone output is a feature mobile DJs will love, as it lets you send different music to different rooms at the same event. DMX lighting control is built in as well.

The learning curve with Engine DJ software is the biggest hurdle. Coming from rekordbox or Serato, I found the workflow different enough that it took me a few sessions to feel comfortable. Hot cues and memory cues management is not as intuitive as Pioneer’s implementation, and the layout, while functional, is not as efficient as what you find on the DDJ-FLX10 or XDJ-AZ. Also, you cannot record your mixes while streaming, which is a frustrating limitation.

Who should buy the Denon DJ PRIME 4+

DJs who want a fully standalone system with the largest touchscreen available and comprehensive streaming options. It is ideal for mobile DJs who run their own events and need multi-room audio and lighting control. Pair it with one of the DJ controller and speaker packages we recommend for a complete setup.

Who should skip it

DJs already deeply invested in the rekordbox or Serato ecosystem may find the Engine DJ learning curve frustrating. If you primarily use a laptop and do not need standalone capability, the Pioneer DJ DDJ-FLX10 offers better value.

11. Pioneer DJ XDJ-AZ – Best Premium All-in-One DJ System

The Pioneer DJ XDJ-AZ (also branded as AlphaTheta XDJ-AZ) is the pinnacle of standalone 4-channel DJ systems. With a 4.8-star rating across 43 reviews, it has the highest user satisfaction of any controller on this list. After spending time with it, I understand why. The layout is directly inspired by the CDJ-3000 and DJM-A9 club standard, and the 10.1-inch capacitive touchscreen can display up to 13 tracks simultaneously. The Playlist Bank gives you rapid access to four playlists, and Touch Preview lets you listen to tracks without loading them.

The audio performance is studio-grade. With a 115 dB signal-to-noise ratio and just 0.0018% total harmonic distortion, this unit delivers the cleanest sound I have heard from any DJ controller. The 206mm full-size jog wheels have Jog Feeling adjust for precise scratching and pitch control, and the 6 Sound Color FX plus 14 Beat FX (including Helix and Mobius) give you an enormous creative palette.

The SonicLink wireless technology is a standout feature. It provides an ultra-low latency wireless connection for compatible headphones, which means you can cue tracks without being tethered by a cable. Built-in Wi-Fi and Bluetooth 5.3 give you flexible connectivity options. The 4-deck standalone playback from USB devices works flawlessly, and the entire experience feels like using a professional club installation condensed into one unit.

The price is the obvious barrier. At over $3,400, the XDJ-AZ costs more than most DJs spend on their entire setup. It is also massive at 30 pounds, and the lack of USB-C inputs feels like an odd omission at this price point. But for DJs who want the absolute best standalone experience money can buy, nothing else comes close.

Who should buy the Pioneer DJ XDJ-AZ

Professional DJs and venues that want a club-standard standalone system. It is perfect for installation in clubs, bars, and studios where the budget allows for top-tier equipment. DJs who can afford it and want the best will not be disappointed.

Who should skip it

Anyone on a budget or who needs to transport their controller regularly. At 30 pounds and over $3,400, this is a serious investment best suited for fixed installations or DJs who are committed to the standalone Pioneer ecosystem.

How to Choose the Best 4 Channel DJ Controller

Choosing the right 4-channel DJ controller comes down to understanding your workflow, your software preference, and where you actually perform. I have guided dozens of DJs through this decision, and the same key factors come up every time.

2-Channel vs 4-Channel: Do You Really Need Four?

This is the question I hear most often. A 2-channel controller lets you mix two tracks simultaneously, which covers the needs of most beginner and intermediate DJs. A 4-channel controller lets you run four decks at once, which opens up layering samples over playing tracks, using stems for live remixes, mixing three or more tracks during complex transitions, and running backup tracks while cueing the next song. If you are an open-format DJ who plays multiple genres in one set, a mobile DJ who needs to keep dance music playing while making announcements, or a creative DJ who wants to push boundaries with live remixing, four channels are worth the investment.

Standalone vs Laptop: Which Workflow Fits You?

Standalone controllers like the Denon DJ SC LIVE 4, Denon DJ PRIME 4+, and Pioneer DJ XDJ-AZ run their own operating system and play music from USB drives or SD cards without needing a computer. The advantage is less gear to carry, faster setup time, and no laptop crashes mid-set. The trade-off is that library management is typically done on a computer beforehand, and you have less screen real estate for browsing tracks. Laptop-based controllers like the Pioneer DJ DDJ-FLX10 and RANE FOUR rely on software like Serato DJ Pro or rekordbox. You get a larger screen for browsing, more processing power for features like stem separation, and the flexibility to switch software if needed. The downside is you always need your laptop, and there is always a risk of software crashes.

Software Ecosystems: Serato, rekordbox, or Engine DJ

Your software choice often determines which controllers work best for you. Serato DJ Pro is the most widely used DJ software globally, with excellent stability and a massive library of expansion packs. Rane and Roland controllers are optimized for Serato. rekordbox is Pioneer DJ’s ecosystem, and it is the standard in most clubs worldwide. If you plan to play in clubs with CDJs, learning rekordbox is smart. The DDJ-FLX10, DDJ-GRV6, and XDJ-AZ all work with rekordbox. Engine DJ is Denon’s standalone operating system. It has improved significantly and now offers streaming, stems, and lighting control. The SC LIVE 4 and PRIME 4+ both run Engine DJ.

Key Features to Look For

Stem separation is the biggest feature advancement in recent years. It lets you isolate vocals, drums, melody, and bass from any track in real time, enabling live mashups and remixes that were impossible just a few years ago. Look for controllers with dedicated stem controls rather than buried menu options. DMX lighting control is valuable if you run your own events. Controllers like the DDJ-FLX10 and PRIME 4+ can control compatible light fixtures directly, simplifying your setup. Balanced XLR outputs are essential for professional gigs. They provide clean, noise-free audio over long cable runs. Budget controllers typically only offer RCA outputs. Motorized platters give you the authentic feel of vinyl turntables. If you are a scratch DJ or coming from a vinyl background, the RANE PERFORMER’s motorized platters make a meaningful difference in how the controller feels under your hands.

Portability and Weight Considerations

If you gig frequently, weight matters more than you think. The Numark Mixtrack Platinum FX at 5.3 pounds and the Reloop Mixtour Pro at just over 2 pounds are easy to carry in a backpack. The RANE FOUR at 18 pounds and the XDJ-AZ at 30 pounds require dedicated cases and sometimes a second person to move safely. Consider where you will be playing and how often you need to transport your gear before choosing a controller at the heavier end of the spectrum.

FAQ

Final Thoughts on the Best 4 Channel DJ Controllers in 2026

Finding the best 4 channel DJ controllers comes down to matching the right tool to your specific needs. For most working DJs, the Pioneer DJ DDJ-FLX10 hits the sweet spot with its club-standard layout, track separation, and dual software compatibility. If you want similar features for less, the AlphaTheta DDJ-GRV6 and its Groove Circuit feature offer outstanding value. And for DJs who want to perform without a laptop, the Denon DJ SC LIVE 4 delivers the best standalone experience at a reasonable price.

My advice is to be honest about where you actually play and what you actually need. Not every DJ needs a $3,000 standalone system, and some working DJs will outgrow a $279 budget controller within months. Pick the controller that matches your current skill level and gig requirements, and invest the savings in your music library, headphones, or monitors. The controller is just one piece of the puzzle.