Have you ever tracked a bass DI and a bass amp only to find that when you try to combine them the results are less than stellar?
The combined sound is unnaturally scooped-out, so you flip the phase of one channel, but that seems to make the combo tinny. This happens all the time and not just with bass.
The solution is the IBP Junior (In Between Phase) Tool, which ingeniously allows the user to dial in continuously variable phase from 0 to 180 degrees. The IBP allows you to easily bring focus to otherwise difficult signal combinations. And it won't break the bank, either.
The IBP Junior is the new, economical, basic version of the Little Labs IBP Analog Phase Alignment Tool.
Little Labs IBP Junior Features :
- Real time all analog phase sweep between zero and one hundred and eighty degrees... and everything in-between.
- Allows mics to be placed where they sound best individually, compromising mic placement due to phase problems is not necessary when using the ibp.
- +4dB XLR balanced input and outputs.
- Rack mountable 4 IBPs fit in a 1U 19" standard rack space.
- Extremely high quality construction. Made in the U.S.A.
The Little Labs family of IBPs (In-between Phase) easily eliminate the undesirable hollow sound when combining out-of-phase and partially out-of-phase audio signals. Designed as a phase problem solving device, the IBP Analog Phase Alignment Tool has quickly become popular among audio engineers as not only a "fix it" tool but as a controlling audio phase creative, tonal color tool. Whether combining direct and miked signals, acoustic guitar and vocal mics, drum kit tom-tom mics, or multiple split-guitar amps, audio signals phase can be quickly and easily controlled with the Little Labs IBP Junior Analog Phase Alignment Tool.
Little Labs IBP Junior functional Description - From left to right :
Phase adjust bypass does just that, bypassing all phase adjust circuitry.
Phase invert is a simple polarity reversal as you would find on a mixing console out is 0 degrees, in is 180 degrees.
Phase adjust 90 degrees /180 degrees selects between two stages (button out) or one stage of phase adjust. This allows a more extreme phase adjustment with a full swing of as much as 180 degrees or a less extreme 90 degrees of phase adjustment.
Phase center lo/hi selects between a higher bandwidth phase adjust (button out) and a primarily lower frequency phase adjust (button in). This and the phase adjust button create the phase curve. It is important to note phase is frequency dependent and is different than time. For example depending on the two sources you are combining, and whether one source is direct and one is miked- between room reflections distance from the cabinet etc. determines what the curve would need to be. (e.g. you need to get the G note in phase as well the A note).
Phase adjust knob determines the degree of phase adjust.
The xlr balanced input is designed for balanced line level sources, the xlr output is impedance balanced and should feed line level pin 2 hot balanced or single ended line level inputs with pin 1 earth and pin 2 hot.
How does the Little Labs IBP Junior work ????
The IBP phase shift circuitry works by running through two passive symmetrical all pass filters. It works entirely in the analog domain. All pass filters are like high pass or lo pass filters as in your EQ or speaker crossover network, but only the phase is affected not amplitude. The IBP has relatively flat amplitude response well past 96kHz.
In most but not all cases at least two all pass filters are needed to recreate what is necessary to correct a phase problem or emulate phase shift in nature. One filter is used for the bottom of the frequency spectrum. The other is used in series for the top, creating a somewhat linear phase vs. frequency response. This is because you need to create a phase curve that is approximately twice the phase shift when you double the frequency.
So for 45 degrees of phase shift at 40 Hz you need approximately 90 degrees of Phase shift at 80 Hz for it to sound natural. "Approximately" ; because every situation is different with sound bouncing around, EQ added (with corresponding phase shift), phase response of speakers, microphones etc. Phase curves in nature have many variables that determine the amount of phase shift vs. frequency. The switch Phase adjust 90 degrees /180 degrees selects between one or two series all pass filters in circuit. Phase center lo hi selects between a higher bandwidth phase adjust utilizing one all pass filter for lo and the second for hi frequencies or a lower bandwidth phase adjust which uses both all pass filters for the lo frequencies.
The IBPs electronics are for buffering and gain make up only. The IBP is entirely balanced and symmetrical from input to output. The output transformer in the ibp allows you to plug freely into balanced or unbalanced circuitry without any interface problems and also allows you to lift the ground.
