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Recording the Guitar Direct - Part 4

Recording the Guitar Direct - Part 4 Brought to you by: guitar.com

Just Press Play Logo Gif 20683Be sure to read the previous article - Part 3 - before continuing onto this next segment.

OK, we now add in the guitar amp into the equation, meaning we will record both the direct signal and the amp signal. So why do this? Why not! OK, that was a silly statement but always remember that experimenting is important to find different sounds.

The typical reason for recording the miked amp and direct signal in this era is to get a nice big clean sound for solos and melody lines.

OK, consider this: You may want a distortion sound (from the guitar amp) and a clean sound from the direct box (to get some clear note definition). The direct sound would typically be placed back in the mix of the two sounds and would most likely be compressed huge to sound aggressive.

Maybe you want to have the direct clean sound incorporate a flanger while the amp sound is non-effected. So many possibilities!

We are recording the direct box signal and the guitar amp mic. Let's keep things simple regarding the guitar amp using one mic on the guitar amp. If you want to use more mics on the guitar amp, refer to Parts 14 through 22 of this series. It's best to record to two tracks since the odds are good there will be a comb filtering problem.

It's important to review the articles regarding recording one mic for set up details, etc. Also you should review article #24 through #26 for pertinent direct box details.

As mentioned in a previous article, the typical direct box have a 1/4-inch female input jack and typically two outputs. One output would be the low impedance output using an XLR connector to route to the mixer input. The other output would be a mult of the input jack using a 1/4-inch female jack to be used for plugging into a guitar amp. Yes, in this case, we will be plugging into the guitar amp BUT DO NOT DO SO YET!

As mentioned in a previous article, a ground switch may also be included on the box. The reason for the ground switch is to eliminate ground hum. When using the direct box, if you have a ground switch, always flip the switch to see which position has less hum. In this case, the ground switch is very important for another reason since no matter what, the direct box will be connected to the mixer as well as the guitar amp.

IF THE MIXER AND GUITAR AMP ARE NOT USING A 3-PRONG WALL CURRENT PLUG, OR IF THE GROUND IS LIFTED ON EITHER USING A TWO PRONG PLUG ADAPTER, YOU MAY GET SHOCKED WHEN TOUCHING THE GUITAR STRINGS OR METAL PARTS ON THE GUITAR AT THE SAME TIME AS TOUCHING THE MIXER METAL OR DIRECT BOX METAL! THE SAME GOES FOR TOUCHING THE AMP AND DIRECT BOX METAL AT THE SAME TIME!

The direct box ground switch may actually not fix the problem depending upon design variables. It's a long story but this has to do with wall current polarity.

Never forget the following!!! When plugging the guitar into an amp with any wall current electronic devices in the chain, especially if the routing is going to the console, NEVER DO THIS WHILE TOUCHING THE GUITAR STRINGS OR METAL PARTS ON THE GUITAR WHILE ALSO TOUCHING THE METAL PARTS ON THE MIXER, AMP, OR EFFECT! If the ground polarity wall current is reversed without proper grounding, you may get shocked! Yes, I said it again but stating it twice was a reminder to me as well!!!

Hey, if you are a guitarist, when playing live, if you're singing into a mic plugged into the PA system, you may have gotten shocked if the wall current polarity was reversed between the guitar amp and PA. If so, you know what a major shock feels like!

Keep this in mind! Avoid using a 3 prong to 2 prong wall connector ground lift. This is dangerous for just the guitar amp alone in possible shock land. Yes, everyone uses the ground lift when they have amp hum (any gear hum for that matter) that can't be eliminated using the amp ground switch. (Note that if your guitar amp is an old design, you can get your amp modified to have a 3-wire AC plug).

If the direct box requires wall current:

1. Do not touch the guitar. Place it on a guitar stand, chair, etc.
2. Plug the direct box and amp into the wall to get power. If the direct box has a power switch, turn it on.
3. Plug the guitar cable into the direct box input.
4. Using another guitar cable, plug into the direct box 1/4 inch output used to plug into the guitar amp.
5. Plug the other end of the cable into the guitar amp input.
6. Now turn on the guitar amp and set to a medium volume.
7. Without touching the guitar, strum all of the open strings with a pick. If you are hearing the guitar through the amp, all is well with the patch so far.
8. Now let the notes die away. Do you hear any hum? If so and your guitar amp has a ground switch, switch it to get the least hum. (The ground switch may have two or three positions). If the direct box has a ground switch (very likely), also experiment with that switch to get the least hum. Go back and forth with both the amp ground switch and the direct box ground switch.
9. Turn down the volume on the guitar amp for now.
10. Now plug the cable to be used to route to the mixer module input into the direct box XLR low impedance output.
11. Plug the direct box XLR output cable (just patched above) into mixer module #9 mic input. (If the direct box is line-level output, and if you have a separate input for line-level on the mixer input, use it.)
12. On module #9, to start, set the mic pre-amp trim to 20 dB. (If you have only one input gain trim pot, that is used for either a line-input level or mic input level. (If the signal from the direct box is line-level, and if you have only one input gain trim pot, set it to zero dB). If you're using a computer hard disk recorder with outboard analog to digital inputs, use the same setting on the input level control to start.
13. Assign mixer module #9 to bus #7 (bus #7 routes to the recorder track we are using for the guitar). Make sure that module #9 is not sent through the monitor chain and is only routed to record track #7.
14. Set recorder track #7 into input mode so we can monitor through the recorder. (In digital land, you may want to monitor the mic-input signal on module #9 BUT only do so if you notice a delay monitoring through the digital mixer and or recorder path. I will get into this subject in future articles).
15. Bring up module #7 (recorder track return) about half way up on the fader throw.
16. Bring up the studio control room monitor level up to a normal listening level.

OK, are you hearing a hum? If not, great! In this case, all should be OK so skip down to Completing The Routing.

Eliminating Shocks

Note: When holding the guitar and touching the amp metal while adjusting controls or powering up/down the amp, remember to not touch the guitar strings and amp at the same time, to play it safe. Yes, at some point you will do so out of habit. Consider the following:

Important: If you want to play it very safe before you pick up the guitar you need a volt meter to check the ground potential. Simply set the volt meter to AC volts using a low-volt scale. Put one probe on a guitar string and the other on a metal part on the guitar amp. If no voltage shows on the volt meter, all is well. If not, its time to call a tech and forget about recording the amp and direct together for now.

(If you are not the guitarist, hip her or him to the previous and the next paragraph and save them unnecessary shocks.)

I do not recommend the following but since many people will not use a volt meter, here is what to do (but do it at your own risk): Lightly touch one guitar string while sitting down and not bent over. Quickly swipe a finger on a metal part on front of the guitar amp. DO THIS AS FAST AS POSSIBLE IN CASE YOU GET SHOCKED. ALWAYS USE A TOP TO BOTTOM MOTION TO HAVE GRAVITY ON YOUR SIDE! Here is another important concept I learned in electric shop in high school: Whenever touching any piece of electronic gear with one hand, it is possible for your hand muscles and possibly your arm muscles to freeze on account of the serious current. Here is a safety tip to keep in mind. You always want to keep a hand free to slam your other hand off the metal that is causing the shock. The idea is to put the free hand in your pocket so you do not touch any other metal. If you're shocked and you cant pull your hand away, use your other hand and as fast as possible, smash away the hand getting shocked. Even better would be to wear rubber gloves that do not conduct electricity to avoid the shock possibility. But then, no one has rubber gloves around when doing such work.

Hide the Hum

Back to work. If you are hearing a hum, its time to go back to the direct box and switch the ground switch once again. That should fix the problem BUT also check the amp to see if any hum was added. If so, one again switch the amp ground switch to eliminate the hum. This is a give and take situation. If you got rid of the hum, all should be OK so skip down to Completing The Routing.

If you still have a ground problem, lets say that you are hearing hum from either the amp or mixer or both. OK, lets run down possibilities.

If you're using 3-prong wall current plugs for both the amp and mixer and direct box, and if you're not in a pro studio that uses home run 3rd prong grounds to a bus that goes to earth ground, (Huh? Dont worry, youre probably not) the odds are good there is an AC ground loop in play. Check your AC POWER BOX to find out the circuit breaker value(s) for the wall plugs in your control room. For example, if your studio has a 20-amp circuit breaker in the control room and all the recording equipment in the control room is safely under that rating, and if the guitar amp and direct box are in the same room, plug ALL EQUIPMENT into a power strip that plugs into one wall current plug. If the amp and direct box is in another room, simply use an extension chord and plug into a power strip that is plugged into the same wall outlet as all the studio recording equipment. This will most likely eliminate the AC ground loop.

If all is ok, skip down to Completing The Routing. If not, here we go with the last resort: It's time to lift the ground using a 2-prong ground lift on at least one of the pieces of gear in the chain. This is possibly dangerous but again, thats what people do! Shut off all of the gear with all of the volume controls off and try lifting the direct box first. Power back up (with all of the volume controls off). If the hum has gone away, great! If not, shut off all of the gear with all of the volume controls off, and lift the guitar amp. You get the drift. Continue the process if needed. If all is OK, skip down to Completing The Routing.

If the direct box does not require wall current and is powered by the mixer phantom power or a battery, or is a transformer passive electronics unit:

1. Do not touch the guitar. Place it on a guitar stand, chair, etc.
2. Plug the amp into the wall to get power.
3. Plug the guitar cable into the direct box input.
4. Using another guitar cable, plug into the direct box 1/4-inch output used to plug into the guitar amp.
5. Plug the other end of the cable into the guitar amp input.
6. Now plug the cable to be used to route to the mixer module input into the direct box XLR low impedance output.
7. Plug the direct box XLR output cable (just patched above) into mixer module #9 mic input. (Note: If the direct box is line-level output, if a separate input for line-level on the mixer input, use it.)
8. Now turn on the guitar amp and set to a medium volume.
9. Without touching the guitar, strum all of the open strings with a pick. If you are hearing the guitar through the amp, all is well with the patch so far.
10. Now let the notes die away. Do you hear any hum? If so and your guitar amp has a ground switch, switch it to get the least hum. (The ground switch may have two or three positions). If the direct box has a ground switch (very likely), also experiment with that switch to get the least hum. Yes, go back and forth with both the amp ground switch and the direct box ground switch.
11. Turn down the volume on the guitar amp for now.
12. On module #9, to start, set the mic pre-amp trim to 20 dB. (If you have only one input gain trim pot, that is used for either a line-input level or mic input level. (If the signal from the direct box is line-level, and if you have only one input gain trim pot, set it to zero dB). If you're using a computer hard disk recorder with outboard analog to digital inputs, use the same setting on the input level control to start.
13. Assign mixer module #9 to bus #7 (bus #7 routes to the recorder track we are using for the guitar). Make sure that module #9 is not sent through the monitor chain and is only routed to record track #7.
14. Set recorder track #7 into input mode so we can monitor through the recorder. (In digital land, you may want to monitor the mic-input signal on module #9 BUT only do so if you notice a delay monitoring through the digital mixer and or recorder path. I will get into this subject in future articles).
15. Bring up module #7 (recorder track return) about half way up on the fader throw.
16. Bring up the studio control room monitor level up to a normal listening level.

OK, are you hearing a hum? If not, great! In this case, all should be OK.

Completing The Routing

17. Ask the guitarist to play the part for the song. While the guitarist is playing, slowly bring up the fader on module #9 (guitar mic fader source) to zero (unity gain). This level setting is typically around 3/4ths up on the fader throw Look at the etching next to the fader as to find the zero mark.
18. If the direct box has an input level control, now is the time to set it to not distort the input circuitry. With the guitar volume full up, have the guitarist play all the open strings with a hard picking attack. Listen for distortion and if any exists, back off on the direct box input level until the distortion goes away. To play it safe, back off on the level a little more.
19. Above Step #2 further adjustment: If you're using an analog mixer and recorder, adjust the pre-amp trim level (possibly line trim level if the direct box is line-level) on the mixer to average zero dB on the recorder track meter for now.
20. Above Step #2 further adjustment: If you're using a digital recorder format, adjust the pre-amp trim (or line trim level if the direct box level is line-level) to -4 dB on the recorder track meter for now (-4 dB is safe in case the guitarist plays louder when recording and the odds are good that will happen!) Always remember that going into the red (past zero) on a digital format meter will definitely clip the A to D converter (analog to digital converter) which is not advisable!!! Digital distortion sounds terrible!!!
21. Mute mixer module #7 and #9 for now since will now add in the guitar amp mic next.

Now its time to add in the amp miking routing. We want to record to two separate tracks to fix comb filtering later. (I will offer a fix on comb filtering if recording to one track in a future article). Remember that the guitar amp mic will route to mixer module #10 and recorder track #8.

22. Plug the guitar mic cable into mixer module #10 mic input.
23. On module #10, set the mic pre-amp trim to 20 dB. (If you have only one input gain trim pot, that is used for either a line-input gain or mic input. If youre using a computer hard disk recorder with outboard analog to digital inputs, use the same setting on the input level control to start.)
24. Assign mixer module #10 to bus #8 (bus #8 routes to the recorder track we are using for the guitar amp mic). Make sure that module #10 is not sent through the monitor chain and is only routed to record track #8.
25. Set recorder track #8 into input mode so we can monitor through the recorder. (In digital land, you may want to monitor the mic-input signal on module #10 BUT only do so if you notice a delay monitoring through the digital mixer and or recorder path.)
26. Bring module #8 (recorder track return) about half way up on the fader throw.
27. Bring up the studio control room monitor level up to a normal listening level.
28. Ask the guitarist to play the part for the song. While the guitarist is playing, slowly bring up the fader on module #9 (guitar mic fader source) to zero (unity gain).
29. Adjustments to Step 2 for analog/separate mixers: If you're using an analog mixer and recorder adjust the mic pre-amp trim level on the mixer to average zero dB on the recorder track meter for now.
30. Adjustments to Step 2 for digital mixer/recorders: If you're using a digital recorder format, adjust the mic pre-amp trim level to -4 dB on the recorder track meter for now
31. Now unmute modules #7 and #9 to get a basic blend. Yes, much more is needed so stay tuned!

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