SOUND AND VIBRATION

by Chuck Bailey

To rattle or not to rattle? That is the question. Well, OK, that may not be THE question, but it is a good one for an angler to investigate. Unfortunately the answers provided by crankbait “experts” are far from being in agreement, and until more scientific research is done, anglers will have to make their own conclusions concerning this controversial issue.

Fact is, crankbait manufacturers are producing crankbaits with and without rattles. Some professional fisherman (who work for their sponsors) swear by rattling crankbaits, others do not. Angling consumers often wonder if the marketing is to sell lures, or catch fish. Obviously the fishing success of some lures containing rattles (like the Rat-L-Trap) cannot be denied, but the question to ask is: Do rattling baits catch fish because of rattles or despite them? And are there times when rattles reduce a lure’s effectiveness?

Before we look at the experience, testimonies, and theories of anglers on both side of the issue, let’s take a look at what we know about fish and their response to sound and vibration…

WHAT FISH HEAR AND FEEL

Do fish have ears? Yes. Do they hear like we do? Almost. The average range of a young healthy human’s hearing is typically from 20 to 18,000 Hz. The upper range of fish is much lower, and it is doubtful if the majority of gamefish American anglers pursue can hear above 1000 Hz. Research suggests that the most efficient hearing of fish, in terms of frequencies, is from about 100 to 300 Hz. (A black bass is basically deaf after 600 Hz.)

Now, this is very important: the inner ears of fish are designed to pick up the upper ranges (higher frequency waves), and the lateral line along the sides of the fish pick up the lower ranges, (lower frequency waves). Do the lateral lines hear sound? No. The lateral lines feel low frequency vibrations. Sound is merely the waves sensed by the inner ears in the upper frequency ranges.

In other words, sound and vibration are both waves that travel through air or water. Sound occurs when high frequency waves in the upper ranges are picked up by the components of the inner ear. Some waves in the lower frequencies cannot be heard, only felt. Hence the lateral line in a fish; a series of cells designed to feel low frequency waves created primarily by movement in the water.

Some say that the lower the frequency of vibration, the farther away it can be sensed. The typical low frequency of rattlebaits can be sensed 60 to 80 feet away. If that’s the case, a fish may “feel” a rattling crankbait a long distance away, but not “hear” it until it comes closer. There is, however, a certain amount of overlap between sound and vibration, where middle frequency waves are both heard and felt.

Take note; sensing vibrations through the lateral line or hearing is not the same as distinguishing what the source is.

It’s important to remember that fish like bass, walleye, pike, etc., are primarily visual feeders. However, the addition of inner ears and lateral lines enhances a predator’s ability to sense the presence of potential prey even before they see it.

Some researchers believe that fish cannot accurately judge direction and distance (like humans can) because their ears are too close together and there are no separate ear drums. Humans, however, have ears farther apart. This allows our brain to compare the time it takes sound to arrive at one ear and then the other, and therefore judge both direction and distance to the source of the sound waves. With sound traveling 5 times faster under water, many researchers believe the waves arrive at both ears of fish simultaneously.

If these researchers are correct, then the most that sound can accomplish in a fish’s world is to alert it to the fact that something is about to enter its environment, perhaps causing enough curiosity to search visually for a potential meal. In clear water where visibility is at its best, the data obtained by the lateral line takes a backseat to the fish’s preferred sense; sight.

In stained or muddy water, however, visibility is limited, and sound and vibration play a stronger role. This is also true when cover is thick, reducing the crankbait’s visibility. In these cases, the approaching crankbait is often heard and felt first. The lateral line refines the targeting process, (sensing the low frequency waves created by water displacement), and further determines which side of the body it is approaching from.

Sound and vibration, (ears and lateral line), help the predator to hone in on the potential prey. But some researchers doubt that most game fish, (especially those that can be taken on crankbaits), can be stimulated to strike with ONLY sound or vibration. Crankbait fish will still depend primarily on sight to help them make the final decision to strike or not. When fish like bass or walleye do strike, they do so with extreme accuracy.

On the other side of the fence are those scientists, like Dr. Richard Fay, who claim some species can indeed determine the direction and distance of potential prey by comparing the differences in the way sound waves vibrate their ear stones. If fish are able to localize the source of sound, both horizontally and vertically in the water column, that means hearing is more important to fish than fishermen realize. If fish can tell the general direction that sounds come from, then logic suggests that the right sounds, (maybe even more sounds), can greatly stimulate a fish to strike a crankbait enhanced with sound and vibration producing rattles.

So far, the experts are divided. Much more research is needed. Are there any conclusions that CAN be made from the existing research? …anything that can help anglers determine if rattles are important or not? Let’s check out two viable theories.

THEORY ONE: RATTLES CATCH MORE FISH!

As we have previously stated; what makes a fish strike is a complex issue. But the majority of outdoor writers and professional fisherman subscribe to the popular view that “rattles catch more fish”. Perhaps you have seen anglers in the sports store, shaking the package next to their ear, listening to the sound it makes, and smiling ear to ear when the rattles echo off the ceiling and floor. Quieter cranks are put back. Why? The fishing celebrity on TV used a crankbait with rattles and slayed them! So… to imitate that success, the novice desires rattling crankbaits. Many consumers head to the cash register assuming the rattles will “wake up the fish!” Hope runs high. Are they wrong to throw confidence behind crankbaits with rattles?

Crankbaits with Rattles Catch Fish The truth is, a lot of fish have been caught on rattling baits. The original lipless crankbait, the “Rat-L-Trap”, (and countless copies), have been responsible for some amazing limits of fish. Especially when thrown over and around submerged grass fields in clear water.

This clear water presentation of lipless rattlebaits seems at first to be contrary to the general rule that states: use rattling lures in murky water, non-rattling baits in ultra-clear water, and choose either in intermediate water clarities. This can be explained by the fact that, though the water is clear, the fish are generally buried down in the grasses, so it is the surrounding cover that makes visibility poor.

Also note that in the case of lipless rattlebaits, they are usually burned through the clear water. So while the noisy rattles alert the buried bass to its coming, the rapid retrieve gives the fish very little time to analyze it when it does show up – often eliciting a reaction strike.

Over the past few decades, almost every shape and size of crankbait has a model containing rattles. And there are many that have proven again and again to catch fish. Those who have won tournaments or netted trophy lunkers with rattling crankbaits have proven that these lures catch fish. So what more is there to explore?

THEORY TWO:
CRANKBAITS CATCH FISH DESPITE THE RATTLES!

Anglers in this camp are fewer in number, and tend to buck the accepted norm, but their logic is compelling and worth investigating. They agree that rattles catch the attention of fish, but they question whether the rattles actually stimulate the fish to strike.

For instance, the lipless rattlebaits mentioned previously may put a fish on alert – that something unusual is coming their way. But in the list of factors that trigger a fish to strike, these anglers consider sound and vibration to be last on the stimulus list. It is their belief that a combination of several primary factors (such as the proper depth, speed, size, color or erratic presentation), that stimulate a strike. However sound and vibrations are considered to be such an insignificant factor, they could be almost ignored. In other words, crankbaits catch fish despite the rattles manufacturers put in them.

In fact, “theory two” anglers rarely buy baits with rattles unless that is the only way the model came. Rattles may more loudly alert fish that a crankbait is coming, but that does not mean sound or vibration are solely responsible for stimulating the fish to travel towards it, or eat it.

Bob Underwood once wrote in his book LUNKER (1970’s) that his time spent underwater, observing bass behavior, convinced him that rattles are almost irrelevant. Specific crankbait models, with and without rattles, were scrutinized underwater. He concluded lure speed and body motion drew strikes, not sound. Size, shape, and color were minor influences that also trumped sound. Sound is almost irrelevant.

Here’s what “theory two” proponents believe: rattles do not necessarily hurt fish response. (We’ll discuss the exceptions in a moment) But even if rattles don’t hurt, rattles do not make fish strike. What’s behind this bold statement?

Imagine a three dimensional bubble surrounding the fish. This is called its “strike window” or “strike zone”. You might call it their “eating zone”. This strike window increases or decreases depending on the fish’s activity level. (The list of factors that influence fish “activity” levels is too long to describe in detail here, but includes water temperature, water clarity, weather fronts, etc...)

If the conditions are right, and a fish is active – the bubble expands and any perceived food coming into that larger strike window will be consumed. If external conditions reduce the size of the window, it’s not that the fish won’t swallow a bait that enters such a small zone, it’s just that the crankbait must find its way to penetrate such a tiny target. In extreme cases, the crankbait must almost ricochet off the fish’s head before it will strike at it.

“Theory two” proponents, knowing that the size of the strike window is controlled by the fish’s activity level, believe a fish will not move beyond the radius of its strike window to strike the lure, rattle or no rattle. If the fish’s bubble has a 3 feet radius, any bait passing 6 feet away may be seen, but will not be eaten. The sound of a rattling crankbait may have been picked up 50 feet away, but until it enters the strike window, it is just something noisily passing by. The bait has to penetrate its strike zone – and that window or bubble is the primary stimulus for an attack. As one proponent wrote “Failure to contact the fish’s strike window results in no bite. A rattle won’t solve this problem.”

The underwater world is filled with sound and vibrations, and most fish are well aware of everything going on around them, though their prey is trying to slip by as silently as possible. Remember, natural prey doesn’t rattle; silent movement is their preferred mode of operandi. And even though crawfish produce a subtle “click” while walking across rocks, they’d wear slippers if it could keep them from being detected by the predators that consider them a delicacy. Although a silent existence is beneficial for prey, predators are well equipped to hear and feel their subtle but tell-tale movements in their watery world.

That’s why, when a non-rattling crankbait enters this environment, (unless it is sitting absolutely still), its movements can’t help but relay its presence to the inhabitants through sound and vibration. Even the crankbaits treble hooks create some noise as they bang against the crankbait’s body. Non-rattling baits are not silent. Fish know they are there!

Obviously, rattling crankbaits catch fish. But in each case, the fish didn’t leave its strike window to get that lure, even though it was heard coming a block away. The key to getting fish to strike is to move that crankbait into its strike window. To simplify this theory: crankbaits catch fish despite the rattles manufacturers put in them.

CONCLUSIONS?

Now some may hear both sides of the sound and vibration controversy and ask, “Well, if rattles don’t help, it also appears they don’t hurt, so why not use them all the time?” Because there ARE times when excessive noise can negatively affect fish; actually spooking them. This is especially true in the early spring when fish move up from the depths to check things out in the clear shallow water. They are extremely spooky and flee at the shadow of a bird flying overhead. At times like this, loud crankbaits are intimidating. This is also true in heavily pressured waters, where fish see artificial baits every day. A subtle presentation is far more effective. Sometimes less is more.

Many anglers have experienced times when their partner throws a similar crankbait and out fishes them 10 to 1. The necessary adjustments should begin with duplicating your partner’s depth, retrieve speed and motion first. Don’t forget to check out your partner’s line thickness, and the length of their cast, (line diameter and casting distance can affect running depth).

If you have carefully imitated those primary factors, then try a secondary adjustment like switching colors. But finally, remember that some crankbait sounds and vibrations are received positively by fish, (like your partner’s), while other sounds spook them, (perhaps yours). Time for a “switch up”; changing sizes or reaching for another model to present an alternative sound and/or vibration.

Be aware; a fish’s preference for certain sounds or vibrations may change from day to day. Fine tuning, (by utilizing a crankbait similar in style, running depth, and presentation), may allow an angler to offer the slight variation in frequency, (sound and vibration), that makes all the difference.

Don’t forget, if you are fishing crankbaits, not all the sounds and vibrations they produce are received positively by fish. Why? …Because no two crankbaits sound alike, (rattling or non-rattling). Variations abound.

Every body shape and lip design affects the movement which creates vibration. Wood baits sound different than plastic, and no two plastics sound alike. The cross-sectional thickness of the plastic shell impacts the sound that inserted rattles make. Some crankbait bodies have large rattles, and some small. Several models have two chambers with both large and small rattles to create low and high frequencies.

And even the materials the rattles are made of can create different sounds and vibrations. Just an increase or decrease in retrieval speed can change the frequencies produced. Two different brands of similarly looking lipless-rattlebaits can produce very different sounds underwater. Some even say that older, well-worn crankbaits sound different from new ones.

Knowing that every crankbait has a unique sound and vibration, the only intelligent conclusion is to experiment out on the water. Start with the conventional wisdom: If the water temperature is warm, the water clarity is stained or muddy, or cover is thick, or the fish are active - start with rattling crankbaits. If the water is cool, super clear, and fish are relatively inactive – crankbaits without rattles may be more effective. But don’t get locked in. There are always exceptions to every rule.

It’s not rocket science, just remember: If crankbaits containing rattles don’t work, try the same model without rattles, and visa versa. Both types have a place in the tackle box. Maybe rattles help and maybe they don’t, but if you’ve tried everything else, make a switch and let the fish tell you when you’re sounding good.

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