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How Do Hi-Fi Speakers Work? Everything You Need To Know

If you’re in the market for hi-fi speakers, you should understand how these speakers work. But when there are so many options available, it can be difficult to find the right one. Knowing the choices that designers make in building their speakers can help you choose the right set.

Hi-Fi speakers work by producing sound via conventional drivers with a cone-shaped diaphragm. The surrounds around the cone damp ringing and distortion, and the voice coils create vibrations on the driver cone’s surface to emit sound. 

This article will teach you how speakers transform electronic signals into music. It describes the various parts of a speaker and reveals some options you have when looking for your ideal speaker. We’ll also offer pointers on how to match your speaker choices to your equipment.

Hi-Fi speakers

Types of Speaker Drivers

Most hi-fi speakers still rely on a design that’s been in use since 1925. Conventional drivers produce sound by using a cone-shaped diaphragm. 

To create this cone, speaker designers rely on various materials:

1

Paper 

Historically, speaker drivers used paper because it’s light and can be made stiff. Designers can change the properties by using different pulp mixes or doping the cone with chemicals.

While many audiophiles prefer more exotic materials, paper remains a popular speaker material.

Wilson Audio, one of the most famous audiophile hi-fi speaker manufacturers, uses doped paper drivers throughout its speaker line. Paper drivers appear in its $15,900 entry-level Sabrina X and its $645,000 WAMM Master Chronosonic.

2

Plastic

Paper cones do poorly in damp environments, so it isn’t surprising that England turned to plastic.

Classic British speakers like the Rogers LS3/5A and the Spendor BC/1 used Bextrene drivers and are still highly sought after today. 

Today, plastic drivers are primarily found in the lo-fi end of the audio market, but other synthetic materials have become popular.

Rockport uses Rohacell cones in its speaker drivers, including its $38,500 Avior II. 

3

Silk

Soft silk tweeters don’t have the precision rigid tweeters can provide. Instead, silk bathes the sound in a flattering glow.

Many speaker designers have moved on to stiff diaphragms, but silk tweeters still have many fans.

DeVore Fidelity uses silk tweeters in its well-reviewed speakers, from the $8,400 Orangutan O/93 to the $85,000 Orangutan Reference. 

4

Titanium

A thin titanium diaphragm can reproduce the signal more faithfully than silk. Some find listening to titanium fatiguing.

A silk dome damps the breakup and distortion, while a badly deployed titanium tweeter foregrounds those faults in painful detail.

Klipsch uses titanium tweeters and midranges for its flagship Heritage line, from the Heresy and Cornwall to the very costly Klipschorn

5

Beryllium

Beryllium is difficult to machine, mainly because its dust is exceptionally toxic. But beryllium has a combination of stiffness and lightness that makes it perfect for tweeters.

As a result, a few very high-end speakers have incorporated beryllium into their speakers. Here’s an example of an expensive tweeter for cars with beryllium.

Canadian speaker manufacturer Paradigm uses beryllium drivers in its Persona series. These speakers range from $7,000 to $35,000 a pair.

6

Ceramic

Ceramic membranes are stiff, light, and resistant to twisting. These qualities result in lower total harmonic distortion (THD) and intermodulation distortion (IMD). Accuton, a German company, is famous for its ceramic drivers. 

Raidho’s Ceramix woofers help create its signature sound. They appear in its $6,400 X1 and its $34,000 X5.

7

Diamond

Stiffness is critical in a driver, and nothing is stiffer than diamonds. A diamond tweeter diaphragm can accurately reproduce sound to above 70kHz.

Since the distortion is driven well above the human limit of 20Hz, diamond tweeters have a very lifelike and detailed presentation

Today, many audiophile speakers use diamond tweeters. Bowers & Wilkins (B&W) pioneered this technology in 2006 with its Signature Diamond. B&W still features diamonds in speakers like its $29,999 800 D3

Surrounds

Designers surround the cone with a ring of material that holds it in place and helps damp ringing and distortion. Many older speakers have pleated cloth or rubber surrounds.

Today, most modern speaker designers use foam surrounds. 

Manufacturers can mass-produce foam surrounds more inexpensively. Foam also has excellent damping properties.

But foam surrounds break down within 12-15 years. Rubber surrounds will last 25-30 years or more, and cloth surrounds will keep indefinitely. 

Are your speakers showing signs of foam rot, such as buzzing and distortion and crumbling and cracked surrounds? Don’t throw them out! Even the most technically challenged can replace their damaged surrounds at home. 

This video from Simply Speakers will teach you the art of speaker refoaming:

Voice Coils

At the driver cone’s apex lies a tight coil of thin wire wrapped around a tube and held in place by a collar with a magnet surrounding the coil.

When electricity passes through this voice coil, a magnetic field develops and interacts with the driver magnet’s field. This interaction produces vibrations on the driver cone’s surface and creates sound.

Field Coils 

Field coils produce their magnetic field by running direct current (DC) through a coil of wire. In the early days of audio, powerful magnets were heavy and expensive, so field coils were widely used.

With the advent of AlNiCo and ferrite magnets, field coils became obsolete.

Today, field coil speakers are enjoying a resurgence. While field coils are bulky and require an outboard power supply, they can produce a more robust and more consistent field than conventional magnets.

German speaker company Voxativ makes a well-reviewed field coil.

Alternative Drivers

While the majority of speakers today use conventional drivers, many audiophiles swear by alternative technologies. 

Electrostatic Panels

Electrostatic drivers use an electrical field to move a thin statically charged membrane. These panels reproduce the music with more speed and accuracy than any conventional driver can achieve.

Some audiophiles swear that conventional speakers sound like music coming out of boxes once you have heard electrostatics.

One of the first legendary hi-fi speakers, the Quad ESL 57, used electrostatic technology. They require a step-up transformer to provide the necessary charge, are notoriously fragile, and don’t play very loudly.

But these and succeeding Quad models remain popular among audiophiles who find their virtues worth overlooking their shortcomings. 

Electrostatic speakers have difficulties reproducing music’s bottom octaves. American speaker designer Martin Logan combines an electrostatic panel with a conventional woofer that handles the bass and lower midrange. Check it out here!

Ribbons

Ribbons use thin metal film with conductors attached or etched into the diaphragm. This film hangs between two magnets. When current passes through the film, the magnetic field makes the film vibrate. 

Ribbons are less fragile than electrostatic speakers: audiophiles find electrostatics have faster transients while ribbons have superior dynamics. (Though be advised, neither ribbons nor electrostatics will play as loudly as conventional drivers). 

Magnepan is the most prominent speaker designer using ribbon technology. Reviewers praise Magnepan speakers for their accuracy and their airy sound. Magnepan panels are generally thin but tall and wide.

If you don’t have room for a $29,995 pair of MG 30.7s, their $1,490 Mini Maggies may be the world’s best desktop system.

Quite a few modern tweeters use ribbon technology. Ribbons are lighter than dynamic diaphragms but more prone to damage from an overly loud signal. RAAL and Heil AMT are the leading producers of ribbon tweeters for professional speaker designers and DIYers.

Crossovers

Some audiophiles say the sound of single-driver speakers like Lowthers is more coherent and immediate than multi-driver speakers. Multiple drivers sometimes blend poorly.

Crossovers can distort at the frequencies where drivers hand off the signal. Getting all your sound from one driver avoids all these issues.

Despite this, most speaker designers use two or more differently-sized drivers in their speakers. Large drivers have difficulties producing the highest frequencies. Smaller drivers will struggle when fed a powerful low note. 

Those who love single-driver designs tolerate those issues. They will live with subdued lows or rolled-off highs for the uncompromised midrange of an excellent single driver.

Most listeners want to hear as much of the audio spectrum as possible. And so, most modern speakers feature multiple drivers connected by a crossover.

A crossover sorts out the signal and sends it to the proper driver. Woofers handle organ pedal notes and bass guitar solos. Higher frequencies go to a smaller midrange driver, with a tweeter reproducing the highest notes and harmonics. (Two-way designs skip the midrange and go straight to the tweeter.) 

A passive crossover provides Low Pass filtering to ensure that only low frequencies go to the woofer and High Pass filtering to make sure only high frequencies go to the tweeter.

The midrange uses Band Pass filtering, which sends only frequencies within a specific range. 

Crossovers attenuate the volume of out-of-band signals for a gradual transition. First Order crossovers cut 6 decibels per octave. Some speaker companies, notably Vandersteen, use First Order crossovers.

But any driver using a First Order crossover must be able to handle frequencies two octaves or more beyond the cutoff point. 

Second, Third, or Fourth Order crossovers attenuate signals at -12, -18, or -24dB per octave beyond their crossover point. These crossovers require more parts and engineering skills, but they also help ensure drivers aren’t forced to reproduce frequencies beyond their comfort zone.

Today, most speaker designers use higher-order crossovers.

There are two ways of ensuring a speaker driver gets the proper signal:

Passive Crossovers

Passive crossovers use resistors, inductors, and capacitors to shunt frequencies to their intended driver. The amplifier pushes a modulated current into the crossover.

As the current passes through, the crossover network feeds the appropriate range of signals to each driver. 

Active Crossovers

An active crossover takes the signal from your preamplifier, transforms it into a digital signal, then converts that signal back into one or more analog currents and passes it along to an amplifier.

A three-way speaker with an active crossover requires three channels of amplification per speaker.

You could achieve this with one six-channel or three two-channel amplifiers.

Active crossovers offer more flexibility than passive crossovers. Audiophiles can use room correction software to compensate for an overly bright or bass-heavy listening space.

They can use a powerful solid-state amplifier for the low end and melodious tube amps for the midrange and tweeter. 

But that flexibility comes at a price. More amplifiers mean more equipment to purchase and squeeze into your audio rack, and you must always check to make sure each driver is getting the proper signal.

If you send a loud low-frequency woofer signal to your tweeter, it may not just distort but disintegrate. 

Important Speaker Specifications

If you’re in the market for speakers, here are some statistics and factors you should check:

Ohms

An ohm is a unit of electrical resistance. Most speakers have either a specified 4-ohm or 8-ohm rating, which is an average. An 8-ohm speaker may dip to 4 ohms or lower at a given frequency. Whenever possible, find out the speaker’s lowest and highest impedance ratings.

This dip often comes at high frequencies outside the normal musical range. The highest note on a piano or piccolo is 4,186Hz, but that tone will include harmonics at 8,000 to 16,000 Hz.

Those tones require relatively little power, and your amplifier should be able to address those current demands without too much trouble. 

More troubling are dips which occur on the low end.

Moving a large driver requires more power than moving a small one. Many “8-ohm” speakers will drop to 4 ohms or lower in the bottom octaves.

This dip provides more current to power-hungry woofers. But if you regularly play hip-hop or EDM at high volume, you may damage your amplifier. 

You may also cause problems with your amplifier by wiring two or more pairs of speakers together. Wiring your speakers in parallel — connecting the red or positive terminal of the first speaker set with the positive terminal of the second — places more strain on your amplifier. 

Ohm rating of speakers in series = product of the speaker’s ohms/sum of speaker’s ohms.

  • 8 ohm to 8 ohm = 8 x 8/8 + 8 = 64/16 = 4 ohm
  • 8 ohm to 4 ohm = 8 x 4/8 + 4 = 32/12 = 2.67 ohm

Hooking your main speaker to a small bookshelf speaker may not seem like a problem. But if that bookshelf speaker is 4-ohm rated (and many small speakers are), you’re presenting a punishing 2.67-ohm load to your amp.

If you’re hooking up two 4-ohm speakers, you’re dropping to a 2-ohm load, which only the beefiest power amps will handle without overheating.

If you must string multiple speakers together, it’s best to wire them in parallel. Attach the negative terminal on speaker A to the positive terminal of speaker B. Then, attach the negative terminal of speaker B to your amplifier. 

Parallel wiring makes the resistance cumulative. An 8-ohm speaker in parallel with a 4-ohm speaker presents a 12-ohm load to your amplifier.

Amplifiers have no problem with higher ohm loads: lower ohm loads can create issues ranging from distortion to fire hazards.

Related article: Do Hi-Fi Speakers Actually Need Running-In?

Efficiency

Hoffman’s Iron Law of Speaker Design states: 

  • You can have a small speaker
  • A speaker with good bass
  • An efficient speaker, which doesn’t require much power
  • Pick any two 

Not all of us have space in our listening room for a pair of refrigerator-sized speakers. Small hi-fi speakers like the Kef LS50 Meta can provide an excellent listening experience and, with output to 47Hz, should meet your bass needs. (If not, you can supplement with this Klipsch Powered Subwoofer.) 

The LS50 Meta has 85dB efficiency and is rated for 8 ohms with a 3.5-ohm minimum. These specs show the LS50 isn’t a taxing load.

One watt of power into 8-ohms (2.83 volts) will produce 85 dB one meter away from the speaker. This volume is about the same decibel level as a lawnmower or diesel truck, so that might be plenty for your listening needs. 

But if you’re listening to your LS50s from a sofa that is 3 meters (10 feet) away, the sound you hear will be at 78.3 dB. Every 3 decibels of extra volume requires twice the amplifier power.

If you want peaks of 95dB, you’ll need at least 50 watts of power. You’ll also be getting perilously close to the LS50’s rated maximum dB rating of 106dB at 1 meter. 

Klipsch Heresy IVs are also 8-ohm compatible, but their efficiency comes in at 99dB/1w. One watt into Heresies gives you 92.3 decibels from the couch. Getting up to 97dB will only require 3 watts. The Heresies will damage your eardrums long before your amplifier breaks a sweat. 

If you have a small room or generally listen to music at modest volumes, the LS50 Metas would be an excellent hi-fi speaker choice.

You could also move a bit closer to the speakers. Moving 4 feet closer to the LS50s and putting your speakers within 2-4 feet of a wall for room reinforcement will give you 86dB at one watt. 

For larger rooms, or for people who like their music at window-rattling levels, the LS50s might not be the best fit. A high-efficiency hi-fi speaker like the Heresy will give you more volume than you will ever need. 

Choosing the proper speaker is not a one size fits all choice. Both are excellent speakers. Your needs and your environment would make the difference as to which is most excellent for you. 

Conclusion

Don’t be seduced by pretty cabinets, and don’t be tricked into thinking the most expensive hi-fi speaker must always be the best one.

Do your research before shopping. There’s a great deal of information on the internet regarding new and vintage hi-fi speakers. 

Read the specifications, but don’t use them as a substitute for listening. Only your ears can tell you which speaker works for you!