Microphones vs Piezo Sensors
With the exception of the Tone Hound Acoustic Sensor, all piezo pickup systems have a distinct disadvantage over other transducers including microphones. Their low end frequency response is weak, while their midrange is excessive. These systems have become outdated because they still have not been able to overcome the usual problematic roll off response of lower frequencies, below 1k Hz, that occurs with piezo-electric sensors. Although EQ systems are adequate for enhancing tonal coloring, they cannot substitute for the loss of natural frequency response that is missing, by adding what is not normally there.Microphones
So… if you mic your acoustic guitar, it will sound more natural, right?
Not exactly! Assuming the microphone you are attempting to use is extremely high quality, you must now find the correct position to get the best recording or sound reproduction possible. Since the microphone is attempting to pickup the summation of all the acoustic signals directed at it, its position is crucial. Where is that position? Should it be 3 ft. away from a guitar? Should be right next to the strings? Should it be right next to the soundhole or the bridge? Each one of these positions will produce different results, which will not necessarily be a correct reproduction of the instruments sound. Additionally, there is a sound signal emanating directly from the top of the soundboard, and a sound signal emanating from the soundhole. Both of these signals are a summation of all the reflected and refracted signals from within the guitar. These signals will vibrate with varying degrees of interactive phase interference. Additional transducers only magnify the problem of reconciling the phase interference. The sound can be also be changed by the size and environment of the room in which you are recording. Even if you find the most desirable microphone location, it will vary from instrument to instrument.Sound Sample - Dynamic microphone 6" from soundhole.aiff (312K file) Other Considerations
At this point, we must consider that an instrument’s sound quality is influenced by many other additional factors to numerous to be discussed here. One must ask themselves, is using a microphone really the most accurate way to record an acoustic instrument? Is there a better way to record the summation or overall tone of an acoustic instrument? Ask any sound engineer and he will tell you that direct input to a mixing board is going to produce a cleaner sound that has no extraneous noise added to the signal. They will also admit that a direct input signal can sound very sterile and unnatural. The use of additional microphones or transducer systems would require you to successfully mix a myriad of additional signals and would require the sound engineer to reconcile the additional phase shift interference that would be produced. Once again the sound would be very unnatural. "Once a tone color has been altered beyond it inception, it can never return to it's original tonal color", therefore equalization is an inadequate methodology for natural sound reproduction. In other words, you can't get there from here!
To solve this problem the transducer must be a single, direct signal input, that correctly reproduces the acoustic instruments tonal quality, while differentiating the subtleties of the instruments responsiveness to the players touch. Does it exist? This author thinks we've gotten pretty close. Read further and see which you think!Phase Variations
Most piezoelectric sensor pickups, just like microphones, have a hard time reconciling the phase variations between the bridge and the top of the instrument. These vibrational variations have a tendency to cancel or weaken the lower frequencies. When additional transducers (pickups) are added to the instrument, additional phase variations between each of the transducers becomes apparent and extremely difficult to blend. Even if each transducer is recorded separately and adjusted for its phase variation the end result is a contrived or artificial sound. Additionally, if the pickup cannot reconcile the phase variations within the acoustic instrument, you will loose most of the natural frequency response!New Technology
The Tone Hound Acoustic Sensor alleviates this problem by utilizing its outer coating of Acoustic Transference Material. This material allows the sensor to react to the vibrations of both the top and the bridge saddle of the instrument without experiencing the phase variance between the two surfaces. The Acoustic Transference Material reconciles the phase variances and then transduces a summation of all signals with the least amount of phase cancellation throughout the piezo sensor, thereby balancing the piezo's harmonic displacement. This resultant effect created is: their are no alterations to the fundamental frequency response the instrument will naturally produce or it's respective harmonics. This means whatever frequencies you put into the pickup, is what gets amplified.Old Technology
In most other piezo systems the preamp seems to be just an afterthought. It is only used to properly step up the signal enough to drive a guitar amp or mixing board. This usually causes a severe roll off or lack of sensitivity to the transduction of lower frequencies from about 1k hertz, while becoming most severe below 300 Hertz. For this reason the current pickup systems on the market sound very unnatural, have overwhelming midrange frequency, and require additional equalization, which still does not rectify the problem.Sound Sample - Standard Piezo saddle pickup.aiff (312k file)
The Tone Hound Piezo Solution
The Tone Hound Acoustic Sensor does not require any additional equalization to reproduce the natural sound of the instrument, because it is the only piezo pickup, known to this author, that has a correctly designed preamp. It’s preamp has been scientifically designed to perfectly match the piezoelectric material’s electrical characteristics. It uses the highest quality instrumentation preamplifier, precisely tuned, to achieve this level of performance.
For this reason, Tone Hound Acoustic Sensors are capable of providing a flat linear response from 2 Hz to 50K Hz., measured at 0db down, and do not undergo the usual problematic roll off of frequency, below 1k Hz. These sensors have been designed to pickup an instruments full range of frequencies without any hint of a need for equalization. This gives control to the player, so they do not have to settle for a tonal reproduction that sounded good to the ear of the preamp designer. With the Tone Hound Acoustic Sensor, what you hear acoustically is what you get from the sensor. Tone Hound Acoustic Sensor Systems simply reproduce the true sound of the instrument without any loss of it's natural tonal response.More Information.The following mp3 file is an excerpt from the song Shadow of Your Smile.It was recorded on a Korg D8 using a inexpensive Classical guitar ($400-$500) with a Tone Hound Acoustic Sensor installed.
Tone Hound Acoustic Sensor Sample.aiff (4.4 meg file)
Shadow of your smile (classical guitar)