INTRODUCTION
“The iAmp offers a lot of tone-shaping flexibility: Four bands of parametric EQ plus four well-voiced presets provide almost unlimited tone-tweaking potential.” This quote from Bass Player Magazine might say it all. Bass players new to EA are not used to the range and flexibility built into the EA Tone Shaping Section. We offer this primer to help get a good working knowledge of the iAmp Tone Shaping Section with advice from the Tone Shaping Section’s designer and bassist, David Inamine. Although many are used to calling this the EQ section we use the more accurate term Tone Shaping. The following quote is from the iAmp manual:

The name says it all. We chose to call this the TONE SHAPING SECTION because that is exactly what it does. It allows you to custom contour your sound. Many manufacturers incorrectly apply the term “Equalizer” to this section of a preamplifier. In truth, an equalizer is used to boost or cut specific frequencies inherent in the listening environment itself, to equalize the room. Instead, the iAMP®800 provides you with extremely pliant tone controls for creating a wide variety of tones from any instrument you play through it. That being said, it is important to remember most listening environments (clubs, auditoriums, rehearsal halls, etc.) actually enhance the frequencies below 50Hz of a bass rig, adding “room resonance” to the sound emanating from the woofer. Conversely, people in the room will absorb the higher frequencies created by the midrange and tweeters. Depending upon the timbre desired, you may wish to keep that in mind, as the sound you are hearing directly in front of your rig is not the same as the sound perceived in the listening environment. When in doubt, back off the bass a little and boost the treble a bit. That way you will be felt as well as heard.

OVERVIEW
The iAMP’s tone shaping section is divided into 2 sections that can be used independently or together. The iAmp has Presets that allow the player to quickly dial in a great sound. There is also a section that allows more detailed tone shaping options.

There are 4 presets, Deep, Contour I, Contour II and Bright. Each Presets has it’s own on/off switch. The following description of the presets is from the iAmp manual:

DEEP: +6dB@50Hz, 1/2 octave bandwidth. Use this control to fill out the bottom end that is easily lost at lower volume settings. The frequency range that this preset affects is the area perceived as the “solidity of an instrument,” or how much strength your sound has. Caution: when engaged at loud volume settings, this preset could cause permanent loudspeaker and hearing damage.

CONTOUR I: -6dB@500Hz, 1/2 octave bandwidth. This preset was conceived to optimize fingerstyle playing. This EQ is based upon players’ request for a “sculpted,” pleasing tone – specially tailored toward an ultimate finger picking sound. It will also take the “honk” out of almost any speaker system. As its name implies, CONTOUR I will eliminate a portion of the lower midrange frequencies, providing wide, deep shaping. At low volume levels, you can use this preset similarly to a loudness control (which typically boost the extreme low and high frequencies).

CONTOUR II: -8dB@750Hz, _ octave bandwidth. This preset was designed to give a great slap/pop sound. This wide filter removes the upper midrange frequencies thereby eliminating the harshness that is often present when slapping the bass. COUNTOUR II makes this playing popular style of more sonically pleasing (without taking away that “oomph” like a compressor sometimes can).

BRIGHT: +8dB@7.5kHz, 1/2 octave bandwidth. This preset emulates the high-end response of a vintage Fender ® Jazz Bass pickup. It gives you a top end “snap” that dull-sounding pickup systems cannot. The tremendous amount of boost also compensates for speaker systems that do not deliver a good upper end response. It can also add sparkle to a lackluster or old set of strings.

Please note that the Tone/Flat switch has no effect on the presets.

For more detailed Tone Shaping options the player can boost or cut the frequencies as desired. The unique design of the iAmp Tone Shaping section presents a visual representation of the effect on your sound. There are four controls:

LO CONTROL: +/-18dB gain control, cut or boost, 40-180 Hz LO-MID CONTROL: +/-8dB gain control, 180-1kHz; switched bandwidth preset, 1 or 1/2 OCTAVE WIDTH PAD HI-MID CONTROL: +/-18dB gain control, 800-8kHz; switched bandwidth preset, 1 or 1/2 OCTAVE WIDTH PAD HI CONTROL: +/-18dB shelving gain control, cut or boost, 1-8kHz

Each control has a diagonal slider that centers the frequency to be adjusted and a rotary boost/cut control knob. Additionally, the Lo-Mid and Hi-Mid have a switch to set the bandwidth or “Q” to either ½ or 1 octave.

USING THE iAmp TONE SHAPING SECTION
Designer, David Inamine designed the Tone Shaping section so that either Tone Shaping option can be used individually or together. He strongly suggests that if both are to be used in conjunction that first you should dial in your desired tone with the sliders and THEN enhance the sound by kicking on the presets. Each slider, from left to right, affects a higher frequency rang; stepping up like a ladder. Here is a step-by-step introduction to the infinite possibilities presented by the iAmp Tone Shaping Section.

1. First engage each preset button, one at a time to see if you get the tone you are looking for. If you still want something different DISENGAGE all Presets. 2. Find the frequency you want to enhance (or diminish). To do this, estimate the frequency range that you want to adjust (Lo, Lo-Mid, Hi-Mid or Hi). Boost the Rotary control for that slider by 5-10dB. Play a note and slowly move the slider until the desired characteristic “blooms”. 3. Now that you have isolated the frequency you can use the rotary control to enhance or diminish it. 4. You might want to add some bottom to fill out the sound on a low volume gig. Adding midrange will help you cut through the mix. You might also want to remove some fret noise or string squeak. 5. Now that you’ve added or removed certain specific frequency ranges, you can engage different presets to affect the overall sound. Be cautious as each of these are additive. If you’ve boosted the bass by 15dB and then turn on the Deep button, you have boosted the bass by 21dB. This can cause serious damage to many speaker systems as well as your hearing!

For a long time it has been mistaken that a solid state amp could not have that big, warm tube sound. The flexibility of the iAmp design allows that and many other sounds. Designer and Bassist, David Inamine suggested the following settings to get that fat tube amp sound.

Control Frequency Rotary Setting “Q”
LO 180 +12 N/A
LO-MID 640 +5 ½ octave
HI-MID N/A 0 N/A
HI 4k -12 N/A
DEEP PRESET ENGAGED

Here is another example for all those “Jacophiles” out there. This setting gives you that great mid-range growl and beautiful ringing harmonics.

Control Frequency Rotary Setting “Q”
LO N/A 0 N/A
LO-MID 640 +10 ½ octave
HI-MID 2k +7 1 octave
HI 4k +2 N/A
ALL PRESETS OFF

A few notes on the above settings. If the Rotary knob is set to “0” then no effect is made to the slider, therefore it is noted as “N/A”. Secondly, these are just estimates, each bass and each person will sound differently. Use this as just a guide.

Finally, one more quote from Bass Player Magazine: “The deep button's moderate bass boost, combined with contour 2's upper midrange dip, produced a full and clear sound that worked especially well with 4-string basses. These two presets are so well voiced I never needed to use the iAMP's powerful parametric EQ during my gig tests. To enhance the EQ section's intuitive feel, EA angles the frequency-selecting sliders to give a better graphic representation of their function. It's easy to find EQ sweet spots by slowly adjusting the sliders.”

CONCLUSION
The EA Tone Shaping Section is extremely powerful and versatile. Use the Tone Shaping section judiciously. Add a little bit at a time.