A recent addition is an Alesis Q2 dual-channel, octal processing effects unit. It is used mainly for tone shaping and adding echoes to the mix and used for studio work or live performances.
There are several patches available on the web for use on this processor. Also the EFTP (echoes from the past) of Charlie Hall fame, uses the Q2 or Q20 as a basis. I have not seen details of any of this work at this time, but have come up with a set of patches of my own. These patches serves the purpose of tone shaping and adding echo to the mix, much like a three-head tape unit and equaliser would do.
Notice the Q2 does not have an extremely-high input impedance, typically around 450K (ideally one would like something around one M-Ohm or better). This loading effect is noticeable on guitars with passive pickups and 500K volume pots such as Strats, Teles, and SGs. Quite noticeable when one back the volume control off a bit and hear the loss of treble. This interaction will affect how effective the tone-shaping patch will suit your purpose.
For purpose of this discussion, a "tape head" is emulated by a Q2 mono-delay element. All delays operate in parallel with staggered delay times, much like a three-head tape machine would stagger delays. Each delay takes its input from the common equaliser's output, and each delay feeds its output into the mix independently from any other delay. The output levels of the delays are then adjusted to suit a particular application. Usually, either a single delay unit dominates, sometimes two delay units operate together.
Also keep in mind that the effectiveness of the effect is somewhat dependent on the input level applied to the Q2. The manufacturer recommends a level where the clipping LED does not activate. I use a nominal level where at least the green LED (-32dB) lights up.
The input signal from the guitar is applied to the R-input (mono) and fed into a three-band equaliser that is common to all delay units. The equaliser is
set up as follows:
Lowpass cutoff = 140 Hz, -9.0 dB. (increase if too mellow)
Middle bandpass = 800 Hz, -6.1dB, 1.0 width.
Highpass cutoff = 1870 Hz, +13dB.
Currently, the delays associated with the three delays are:
Delay 1 --- 172.6ms (231.7 bpm) 1/4T
Delay 2 --- 280.3ms (142.7 bpm) 1/4T
Delay 3 --- 344.8ms (174.0 bpm) 1/4
1. Each delay's feedback is set in different patches.
2. Each delay unit receives input only from EQ unit.
3. Each delay unit output only to L/R output.
The following echo patches are fairly usable. Most have been verified against a Zoom 508. The patch number shown follows Zoom 508 nomenclature:
00- A1 --- 1(65%, fb=25) + 2(65%, fb=40) + 3(65%, fb=40)
01- A2 --- 1( 0%, fb=25) + 2(15%, fb=25) + 3(70%, fb=60)
02- A3 --- 1(60%, fb=35) + 2(60%, fb=35) + 3(60%, fb=35)
03- A4 --- 1( 0%, fb=25) + 2(15%, fb=25) + 3(63%, fb=25)
04- B1 --- 1(80%, fb=50) + 2(70%, fb=50) + 3( 0%, fb=50)
05- B2 --- 1(60%, fb=25) + 2(15%, fb=25) + 3( 0%, fb=25)
06- B3 --- 1(85%, fb=30) + 2(85%, fb=30) + 3(85%, fb=30)
07- B4 --- 1(50%, fb=45) + 2(50%, fb=40) + 3(75%, fb=50)
08- C1 --- 1(10%, fb=10) + 2(35%, fb=20) + 3(60%, fb=20)
09- C2 --- 1( 0%, fb=40) + 2(55%, fb=40) + 3(66%, fb=25)
10- C3 --- 1(85%, fb=40) + 2(85%, fb=40) + 3(85%, fb=40)
11- C4 --- 1(75%, fb=45) + 2(75%, fb=45) + 3(75%, fb=45)
12- D1 --- not done yet
13- D2 --- not done yet
14- D3 --- not done yet
15- D4 --- 1( 0%, fb=25) + 2(15%, fb=25) + 3(70%, fb=40)
16- E1 --- 1( 0%, fb=40) + 2(60%, fb=31) + 3(20%, fb=25)
17- E2 --- not done yet
18- E3 --- not done yet
19- E4 --- not done yet
20- F1 --- not done yet
21- F2 --- not done yet
22- F3 --- not done yet
23- F4 --- not done yet
Feel free to modify and use these patches for your own purpose (use at your own risk!).
Keep on jamming!