How to Match a Cab to Your Head

From basic safety protocols and amplifier efficiency to pairing up the right speakers and cabinet configurations in order to find your perfect tone, matching a guitar cabinet to your amplifier head can seem like a daunting task. Luckily, we’re about to break down everything you need to know in layman’s terms so that you can get up and running without burning down anything while you’re at it. But there are certainly some specifics to bear in mind when dealing with powerful electrical routing onstage and in the studio. Depending on your current setup and tonal preferences, some of these rules of thumb can fluctuate, so we’ll explore some rules that apply to a variety of guitarists. We’ll also toss in some killer heads, cabs, and even some discounted bundles that are sure to turn heads!

So, whether you’re working on your next build, upgrading (or condensing) your current setup, or simply looking for a bit more clarification on the matter, strap in as we dive into everything for you to consider when matching a guitar cabinet to your amplifier head.

Consider ImpedanceTube vs. Solid-state ExpectationsConsider Power Handling (Wattage)In Terms of Tone & PresenceSpeaker Magnet TypesSpeaker ConfigurationOpen-back vs. Closed-back CabinetsBrand Matching (Sound & Aesthetic)

Consider Impedance

Okay — we’ll start off with the elephant in the room! Impedance awareness is one of the main factors in putting together a safe half or full stack in your practice, studio, or performance space. But what exactly is impedance?

Impedance, measured in ohms, refers to the total combined load that your speaker cabinet is going to place on your chosen amplifier head. On the back of each amplifier head, you’ll find a minimum impedance load displayed next to the amp’s output socket(s). This minimum rating means that the ohmage of your cabinet (or the combined ohmage of multiple cabinets you’re using) cannot fall below that minimum number. Generally, you won’t see amplifiers with minimum ratings of more than 8 ohms, and in a lot of cases, you’ll even have multiple impedance outputs to choose from.

Impedance loads displayed next to each speaker connection on a Marshall ST20H Studio JTM 20-/5-watt tube amplifier head.

Guitar Speakers: Resistance vs. Impedance – What’s the Difference?

How To Choose a Guitar Speaker Cabinet – Part 4

So, how does one calculate the resistance of cabinets?

If you’re using a single cabinet, then it’s fairly simple. The resistive load (in ohms) is displayed on the back of the speaker cabinet next to the input jack(s). For example, a single 16-ohm cabinet is safe to connect to your amplifier’s displayed 8- or 16-ohm output.

However, if you’re using two cabinets (but only two), then the impedance is calculated as one-half of each cabinet in use. So, connecting two 16-ohm cabinets will create a total impedance of 8 ohms. This is due to the fact that the input jacks on most speaker cabinets are wired in parallel. Because of this, it is incredibly important to always keep in mind the minimum impedance load of the amplifier head you’re using. If that total impedance falls below the amp’s minimum load, then it will cause the amp to overheat and damage your gear.

It’s worth mentioning that if you’re planning to use multiple cabinets or to daisy-chain them, then it is always best to use cabinets with matching impedances. When cabinets of different impedances are linked, calculating the total impedance is far more complex, which can make it difficult to ensure your setup will operate safely. You should also make sure that your cables are certified speaker cables and never standard guitar/instrument cables because instrument cables are not designed to accommodate amplifier-level signals.    

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Tube vs. Solid-state Expectations

It’s important to note that these guidelines can vary depending on whether you’re using a tube-powered or a solid-state amplifier. In the case of a tube amplifier, you’ll need to be sure that the impedance of the cabinet matches exactly to the minimum impedance load displayed on the output of your amp head. Sometimes, there will be a selector switch that enables convenient impedance switching to accommodate cabinets with different loads.

Conversely, a solid-state amplifier can be used in conjunction with a cabinet that has a higher impedance than its minimum impedance load without causing harm — though exact impedance matching is always recommended. If a higher-impedance cabinet is used, then the stack will still operate safely. But so long as you are aware of the impedance values that amp and cabinet builders provide on the back panel of the units, you’ll be able to make a safe and efficient game plan.

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Consider Power Handling (Wattage)

While impedance is a huge factor in choosing a cabinet to match your amplifier head of choice, it is by no means the only one. Another key point to consider is power handling. Power handling is measured in watts and is the power that a speaker cabinet must be able to handle. This concept is easier to visualize, but it’s equally as important!

First and foremost, a speaker cabinet’s power handling must match or exceed the maximum output power of the amp head. So, if an amplifier head outputs 300 watts of power, then the cabinet should be able to accommodate 300 watts at a minimum. If the power handling of the speaker is too low, then you may damage your cabinet, amplifier, or both. Not advisable!

When you look at connecting a cab to your amp head, the wattage ratings of the head and the cab do not have to be identical. In fact, smaller heads can be paired with cabinets of all sizes — as long as the cabinet’s power rating is more than the head’s output power. You’ll often see guitarists playing compact heads through large cabinets, even onstage. You can connect smaller combo amps to large cabinets if the setup you’re working with requires it.

If you are running a stereo rig, then all the same caveats apply. The stereo power amp (left and right channel outputs) will be connected to cabinets (left and right) that follow all the guidelines mentioned above.

In Terms of Tone & Presence

Now that the scary stuff’s out of the way, we can move onto the more exciting side of matching a cab to your head: the SONIC effects! There are plenty of factors that play a part in terms of how your stack is going to actually sound — some less obvious than others. We’re going to take a look at four categories: speaker magnet types, speaker configuration, open-back and closed-back designs, and brand matching. Each of these categories impacts either tone, presence, style, or all of the above! Let’s get started.

Speaker Magnet Types

Your cabinet is a defining feature of your sound, and the determining component is the speakers. Whether you’re choosing a modest single-speaker solution or springing for a quad-speaker armament, it’s important to know the differences between the three main speaker magnet types. These components will have the largest tonal impact on your sound and will help you choose the cabinet that’s the right match for both your guitar and amp head.

Alnico magnets have the longest history in guitar amplification, offering an alloy blend of aluminum, nickel, and copper. There is a natural warmth, detail, and sensitivity to these speakers that all provide a truly timeless tonality. As a result, alnico-equipped cabinets are superb choices for studio setups or low-volume situations where maximum tonal vividity is paramount. Celestion offers some of the best-sounding, most gorgeous-looking alnico speakers on the market today — they can be found within many famed combos and cabinets retaining that stunning bygone sound, including the 30-watt, 2×12-inch Vox AC30C2X and 45-watt, 4×10-inch Fender ’65 Super Reverb combos.  

During the 1960s, as guitars and their accompanying amplifiers skyrocketed in popularity, the development of the ceramic magnet saw a more cost-efficient means for speaker engineering. But affordability isn’t the only benefit to this diverging design! Ceramic magnet speakers are widely considered jacks-of-all-trades, offering players an enormous tonal spectrum in addition to better handling of high-volume situations, like stage performances. Jensen produces quite a few fine examples of the ceramic magnet speaker, coming available in sizes to fit any configuration you require. Many cabinets by Marshall feature ceramic magnets as well, including the 140-watt, 2×12-watt Marshall SV212 Studio Vintage vertical extension cabinet.

The third type of speaker magnet to consider is neodymium. This more recent magnet type presents a lightweight alternative to both alnico and ceramic options and essentially provides the best of both worlds in terms of tone and response. You’ll get similarly detailed tonality and sensitivity to that of alnico magnets, with the balance and performance-grade operation promoted by ceramic magnets. These speakers have been increasing in popularity for some time, and Celestion has a great grasp of the neodymium game. One exceptional example of these speakers in action is the Celestion G12 Neo Creambacks in the 120-watt, 2×12-inch Orange PPC212 V cabinet.

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Does Your Guitar Speaker Matter?

Speaker Configuration

The configuration of the speakers within your cabinet is arguably just as important as the speaker type, if not more! And the sonic equation is pretty darn simple, too: more speakers equals more power! Not only in terms of volume but power handling for your amplifier, too (which, if you recall from earlier, is pretty important!). The great news is that because cabinets come in all shapes and sizes, there’s a configuration out there that’s going to be absolutely perfect for your exact applications. But what exactly are the options?

Well, the size of a guitar cabinet is based on the diameter of the speaker(s) within it. However, most guitar cabinets feature speakers with 8-, 10-, or 12-inch diameters, with the occasional outliers designed to accommodate miniature amps and boutique builds. Depending on the cabinet model, single-speaker designs can provide power handling anywhere from below 50 watts to more than 250 watts. With so many to choose from, you’re bound to find an option with the right presence and bulk to meet your needs. For these single-speaker designs, we’d recommend sticking to home spaces and studio work. And most of the time, that’s all the power you’re going to need.

How about if you’re planning to gig? Or simply want the extra-beefy signal breakup? Well, you’ll need more power, of course! Luckily, many guitar cabinets are available in both 2- and 4-speaker configurations as well, giving you plenty of volume to power through any show. From stylish and rocksteady 2×10-inch cabs to monstrous 4×12-inch Marshall stacks and the like, there’s a cabinet configuration to satisfy every gigging guitarist.

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Open-back vs. Closed-back Cabinets

The third musical factor in matching a cab to your head is whether or not the cabinet is of an open-back or a closed-back design. Both of these designs can leave particular sonic footprints depending on the space, so it’s good to have an idea of which resonates most with your musical direction.

An open-back cabinet will offer both forward and rearward projection, causing a bit of low-end and focus loss when heard head-on. The benefit, however, is a more dimensional sound that can prove vital for characterful studio recordings, more easily heard rehearsals, and more intimate performance spaces. Because the rear openings vary in size from cabinet to cabinet, you’ll experience greater focus with smaller openings than you will with larger ones, so be thinking about how much focus you’re willing to sacrifice once you land on a good candidate.

On the other hand, a closed-back cabinet is incredibly attack- and forward-projection-friendly! You’ll also notice a tighter responsiveness, especially in terms of those lower frequencies. With these factors in mind, closed-back cabs are quite useful in the recording studio if you’re trying to capture an amp tone in its purest form. However, for hard-hitting output, particularly on medium-size and larger stages, you’re going to need all of the presence you can get, regardless of whether you’re miking or flat-out projecting. In such cases, a closed-back cabinet is going to be your best friend.

Brand Matching (Sound & Aesthetic)

This last category is brief and not quite as technical, but it’s no doubt one of the biggest factors for a lot of us gearheads. Brand matching between amplifier heads and cabinets goes beyond manufacturer loyalty; there’s often a huge draw to keeping things in the family! Amp builders will design cabinets with specific components in mind that will bring out the very best of what their amplifier heads have to offer. For example, reissued amplifiers that tribute seriously historic designs are likely best suited to alnico magnet speakers. So, you’re best bet is to find a cabinet in your manufacturer’s lineup that can accommodate.

The other truth to brand matching is pretty obvious — it looks really good! Stack your 100-watt Marshall DSL100HR tube head atop its trademark angled cab companion or your 30-watt Vox AC30CH tube head atop a diamond-grille-matching 2×12-inch cab, and there’s just no denying the aesthetic captivation. Amp building — and gear in general — is a culture, with tons of pieces to the puzzle that produce the glorious final product. But it isn’t a one-size-fits-all matter. So, experiment a little! Find the look and dimensions that fit your space or performance needs, and give your gear the same treatment that you’d give your music. Not only will things sound great, but you’re bound to turn a few heads along the way, too.

Sweetwater did a seriously deep dive into auditioning guitar cabinets — 25 cabs were assembled and then listened to side by side. Check out the article below!

Guitar Cabinet Shootout – with Sound Samples

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Shop Amps & Cabs at Sweetwater Today!

Still with us? That’s a lot to consider! And with all of these factors in mind, it can still feel a little intimidating for first-timers and curious connoisseurs alike. If you have questions, then we’re here to help. For all the best amps, cabs, speakers, and accessories available, and to find your perfect cabinet, give one of our outstanding Sweetwater Sales Engineers a call at (800) 222-4700. We want to make sure that the demands of your existing setup and musical space are met with unanimous approval.
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