Why a broken in speaker sounds different, and how to capture that sound with a new speaker

So, you love your buddy’s tone and really dig the speakers he’s been playing for the past six months! You go out and buy the very same speakers, put them in nearly the same rig, but it just doesn’t sound the same. Your dilemma is not uncommon. Many variables could be responsible for such a situation, but most likely it is a result of your friend’s speakers being “broken-in,” while yours are still brand new.

Simply put, all speakers are built to meet certain specifications right out of the box. Most manufacturers work diligently to ensure that happens, and tolerances are usually pretty tight. As soon as the speaker has been put into service, all that changes though, and so does the tone. The sonic results you’ll hear from break-in are: warmer, smoother highs, an increase in overall warmth, and a slightly deeper, fatter low end.

The components making up the speaker’s suspension are primarily responsible for such changes: the spider (the lower suspension) and the cone edge (the upper suspension). As the speaker is used, these components start to lose some of their compliance or stiffness, which results in changes to parameters mentioned above, as well as to tonality. The stiffness of the cone can also be impacted over time by use, but plays a subordinate role in the phenomenon known as “break-in.” The frequency response graph shows how a speaker might change during this process.

A good way to characterize speaker break-in is to consider it as a curve. It begins with the first note you play and progresses fairly rapidly through the first several hours, or days, of playing. Changes in the speaker will continue throughout its usable life cycle, but they slow down dramatically and become unnoticeable to even the most seasoned ears. In other words, the curve is initially pretty steep, but becomes much flatter after several hours of use, and even flatter over an extended period of time. The noticeable amount is where the term “break-in” or “broken-in” is commonly used.

Players often wonder if it’s necessary to put the speaker through some sort of break-in process. Technically speaking, there is no benefit to the life of the speaker or other glaring justification for it—other than to avoid going through a phase where you’ll notice changes. Often, it’s even fun and enlightening to experience playing through the break-in period. However, you wanted your tone to be like your buddy’s, so you’d like to get there now, right? If that’s the case, you may want to consider some sort of procedure to get your speaker sounding the way it will be expected to for the majority of its usable life cycle. Let’s talk about how you can do that.

1. Recorded music is one of the most common methods to induce break-in. A good stereo receiver playing music at moderate volume for several hours or even days is a safe and reliable method. Use good judgment, and don’t overpower the speaker or feed it tons of low-frequency material. If it is distorting, you’re probably damaging the speaker. Get as much cone movement as you can, but you will know when you’re going too far.

2. Physical movement certainly works, if you have the time to sit there and work the cone up and down. I don’t recommend it, though. You could damage the speaker—or reinforce your significant other’s view that you’ve taken this guitar thing way too far!

3. Hanging speakers face down is often suggested as an option. In reality, that promotes suspension sag, which can displace the coil in relation to the top plate. This is not breaking the speaker in, but likely changing the intended tonality of the speaker forever. The stiffness of the suspension components hasn’t changed with this method, right?

4. Variacs are variable AC voltage controls with distortion-free output. This source will get the speaker moving, typically at 60Hz. If you can get your hands on one, it is a great way to break a speaker in.

5. Noise signal generators are my personal preference, accompanied by a multimeter to read the output voltage, and a frequency counter to read frequency. I’ll play a 20Hz–30Hz sine wave through the speaker with 15V–20V for four to eight hours. It’s an effective method, but pretty abusive. You have to use very good judgment in setting it up. I’ve been known to burn up a voice coil by mistake. This is likely not a practical solution for most people, because the equipment is not readily available.

6. Just playing it is a safe and reliable method. Play it hard and play it loud to shorten the time required. Don’t damage your hearing by any means! Fifty to a hundred hours should get you to the point that you no longer recognize tonality changes.

Look for more on this topic in future installments. We’ll take it a step further by breaking in speakers of the same model using various methods. We’ll use some loudspeaker measurement systems to track our progress and resultant speaker changes. Maybe we’ll solve all the mysteries!

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How speakers break up, and what you can do to control the noise.

Voice Coil Winding Height

Top Plate Thickness

Voice Coil Overhang
I often hear, “My speaker breaks up too early so I need a higher power speaker,” or, “I want earlier break-up so I need a lower power speaker.” In most cases, both may be true. However, the power rating is not a contributor. I cannot emphasize this enough: the power rating does not contribute to the break-up mode of the speaker. The rate of break-up depends on the cone density and the relationship between the top plate thickness and voice coil winding height. Compare the latter with a parameter called Xmax, which represents the maximum linear excursion.

Simply stated, the Xmax is the height of the voice coil overhang above and below the top plate and magnetic gap. As the speaker is pushed to a point where less wire is in the magnetic gap, distortion and non-linearities should begin to occur. At an extreme, a mechanical failure would result from playing the voice coil out of the magnetic gap. This extreme would exceed the Xmax and is hopefully beyond the power rating of the speaker.

More Xmax should result in less break-up because more travel is required to push the voice coil wire out of the magnetic gap. However, considering the Xmax figure tends to be relatively low on guitar speakers, this doesn’t lend a lot of insight. You’re essentially comparing speakers that all have lower Xmax. In reality, the real mojo with break-up comes from the cone. For instance, if a guitar speaker with the highest Xmax has a lightweight, thin cone, it’s going to break-up early. So you ask, “How do I know if the cone is lightweight and thin?” Honestly, I’ve never seen raw cone specifications published. Ultimately, we must rely on the speaker manufacturers’ suggestions and expressions regarding break-up modes.
It’s important to consider the rate of speaker breakup. You can look at it as another variable in getting your tone. If your overdriven sounds are a little ratty or harsh, you should try a cleaner speaker. The cleaner speaker will hold together better and should produce a more articulate sound, and you will be relying more on your amp to get your overdrive.

On the other hand, maybe you’re not getting enough dirt at low volumes. A speaker that breaks up earlier may solve the problem. You may even find that you desire a certain speaker’s break-up characteristics. Some of them can be really sweet. I’ve noticed that really good players learn where their speakers break-up and use it to their advantage. They never have to adjust their amp. They use the volume knob on their guitar and vary their pick attack to get exactly the tone they want, when they want it.

Hopefully, this gives you new ideas to improve specific areas of your tone. I encourage you to listen more critically, to find exactly what needs improving and to define your ideal tone

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How speaker characteristics affect mids and highs

We pick up where we left off last month with more tips on the specifications and characteristics you should consider when choosing appropriate speaker upgrades. Last month I discussed typical comments I hear from players related to low-end. We discussed speaker characteristics that affect low-end and how to improve it. This month we’ll do the same for mids and highs. Next month, we’ll look at speaker break-up modes. As I stated last month, I challenge you to listen to your current speaker(s) more crucially, and determine specifically what you want to change about your tone.

Guitar Speaker Tone Center Guitar Speaker Tone Center
Figure 1
Figure 2

The way a speaker delivers the mids is an important key in achieving good tone. I receive too many different comments about mids to list, but I can give you some ideas on what to look for and compare. Guitar speakers generally have similar frequency responses (figure 1). They rise steadily until about 1kHz. They have a suck-out around 1.5kHz. They peak at 2kHz and extend out to 4kHz-5kHz. Granted, the response is a measurement of the fundamental and doesn’t account for harmonic content, which creates interest, detail, complexity and fullness. However, the response curve is a good starting point and can give us some clues before hearing the speaker. If you’re looking for a scooped (or lack of mids) sound, find a smiley face-type response between 300Hz and 1kHz (figure 2). If your mids sound too forward and aggressive, you will need less of a peak around 1kHz and a wider, deeper suck-out between 1kHz - 2kHz (figure 3, blue curve). To improve the definition of your mids look for more energy around 1kHz (figure 3, red curve). Our ears interpret wider, flatter areas as warmer and smoother, while peaks and dips sound more forward and aggressive (figure 4). This could be good or bad, depending on what you want.

Guitar Speaker Tone Center Guitar Speaker Tone Center
Figure 3
Figure 4

A frequent concern I hear about highs is, “My highs are too ice-picky or harsh and thin.” As discussed last month for improving lows, consider a larger voice coil, which will also eliminate unwanted highs. The low-end increases while top-end extension decreases.

Guitar Speaker Tone Center
Figure 5

The dust cap is a key contributor to the top-end response. A small dust cap, assuming it is also lighter, will produce higher sensitivity and more extension. To subdue that effect, look for a speaker with a larger dust cap. More mass will have an inverse effect. Also, take notice of the material. A cloth, screen-type cap is commonly used on guitar speakers and sounds relatively transparent. Hard paper caps sound brighter. Felt caps add warmth and smoothness to the highs. The frequency response graph is also a useful tool for the highs. Notice peaks and dips around 2kHz-5kHz and compare the levels (figure 5). A speaker that exhibits a variance of peaks and dips will typically sound brighter than a speaker that is flatter, smoother or less extended in this region. An ideal way to tame a bright amp is with a hemp cone speaker. Hemp is a denser, stiffer material than traditional paper pulps, and it really colors the tone. Hemp speakers are much warmer and smoother with subdued highs. They also tend to break-up later, but we’ll pick up with break up next month.

Anthony “Big Tony” Lucas
is a guitarist and Senior Lab Technician at Eminence Speaker LLC, where he specializes in guitar-speaker design and customer support. Big Tony has been with Eminence for over 10 years and is responsible for many well-known guitar speaker designs.

I’m often asked, “What is the best speaker for this amp, playing style or artist’s tone?” “Best” is very subjective! My token answer is always, “What characteristics are important to

I’m often asked, “What is the best speaker for this amp, playing style or artist’s tone?” “Best” is very subjective! My token answer is always, “What characteristics are important to you to improve your tone?” If you need help choosing the right speaker then seeking advice from your favorite tone guru may be the way to go. This might be someone who has heard a lot of speaker and amp combinations and can suggest the most appropriate speaker based on your style and desires. However, I challenge you to listen to your current speaker(s) more critically. Determine specifically what you want to change about your tone. Then decide what speaker(s) might be most appropriate.

Guitar Speaker Tone Center
Figure 1
There is a lot of misunderstanding about what specifications and characteristics to compare. This month and next, I will offer you some tips on how to choose appropriate speaker upgrades for specific areas of your tone. We will start with the low end.

One of the most common things I hear is, “My low end is flabby/muddy so I need to get a speaker with less low end.” Actually, you need a speaker with more low end. Your bass sounds poor because the speaker is not responding well to the rest of your tone chain. If you use a speaker with more low end definition it will sound cleaner and more controlled. There are several specifications worth considering for a speaker with better low end. However, making a comparison may be impossible if information on your current speaker is not readily available.

Consider using a speaker with a larger voice coil diameter. You can measure this if you don’t already know what you have. Voice coil diameters on guitar speakers are typically 1”, 1.25”, 1.5”, 1.75” or 2”. In order to find the diameter of the voice coil, measure at the cone’s apex (see figure 1). Take a string and wrap it tightly around the apex just above the spider to find the circumference. Then divide by 3.14 to calculate the diameter. The cone and spider neck were also a part of your measurement and must be taken in account. You will need to round down to the closest voice coil size mentioned above.

The larger a voice coil diameter, the larger the mass of the piston. This basically shifts or narrows the frequency response. The result is more low end and less top end extension, while power handling also increases. Some players are skeptical of using higher powered speakers with smaller powered amps. Remember, you should consider the SPL rating. This represents the output measured at 1 watt, 1 meter from a microphone. It gives you an indication of how loud the speaker will be. Guitar speakers are typically abundant in SPL and don’t require much power to push them effectively or to make them loud.

Some players opposed to larger voice coil guitar speakers, specifically 2” voice coil speakers and above, feel they sound sterile. That’s simply a preference — some will like it, some won’t.

Others worry that their bass will be too emphasized. I often hear, “I don’t want a ‘boomy’ or ‘woofy’ bass.” That’s a legitimate concern, but you should have multiple choices within a certain voice coil range. All your choices with a larger voice diameter should produce more bass than what you currently use, but they won’t all have the same amount. One with a wider frequency range will sound less defined on the low end. More aggressive highs and mids will tame the amount of low end you hear because your ear will interpret more of a full spectrum sound. Use the voice coil size as a starting point. Then compare further specifications and characteristics that appeal to you.

Another way to judge the low end response is to compare magnet size and the Qts parameter. A smaller magnet increases the Qts. A higher Qts theoretically should lend more bass. The key to make this comparison relative is to ensure other details are similar. You can’t simply choose the speaker with the highest Qts and assume it produces the most bass. Make sure to compare speakers with the same voice coil diameter, similar response curves and maintain other specifications are fairly similar. Then it’s safe to assume that a smaller magnet and higher Qts will produce more bass.

I hope this gives you some ideas on how to achieve cleaner, more articulate bass. Next month we will talk about the mids, highs and break-up characteristics.

Anthony “Big Tony” Lucas
is a guitarist and Senior Lab Technician at Eminence Speaker LLC, where he specializes in guitar-speaker design and customer support. Big Tony has been with Eminence for over 10 years and is responsible for many well-known guitar speaker designs.