A Guide to Re-Amping Techniques

Re-amping is a technique that gained a lot of popularity in the last 15 years. The technique’s obvious advantages are numerous:

  • Direct recording is an ideal way to reserve tonal flexibility for mixing (especially useful in the DIY world);
  • Instrument amplifiers and stomp boxes offer virtually limitless opportunities to create the right sound with a not-so-virtual interface;
  • It’s fun, which is still allowed.

Sometimes the re-amping goal is simple. An electric guitar can be recorded direct while monitoring a software amp simulator. During mixing the direct guitar track (sans faux amp) will be re-recorded through an actual amp.

Re-Amp Signal Flow

Other popular uses include adding some grit to a direct bass track, rescuing underwhelming keyboard sounds, or using your favorite stomp boxes as outboard processing. In any case, if the goal of the process is amp-related, you can be sure it is also more or less distortion-related.

Sompbox Outboard Workflowa

Here are some ideas about how to get the most out of the re-amping process.

Gain Staging

As pictured above, the re-amp process requires us to adapt the balanced, relatively low impedance output from our DAW to the unbalanced, high impedance input of the amp or pedal(s) in question. The biggest factor in managing the gain staging of your re-amping signal chain is your choice of adapter.

The two choices are:

  1. A purpose built adapter, like the ones made by the company called Reamp, or Radial Engineering; or
  2. A passive direct box (so say some).

The purpose-built re-amping devices (most of which are derivative of John Cuniberti’s early 1990’s design) have the distinct advantage of being designed to operate in the amplitude and impedance ranges typically found in +4dBu pro audio and the instrument amplifier world. The same cannot be said of a typical passive direct box. These are important characteristics of inductive systems.

That’s not to say you can’t get the signal flow happening with a passive DI and an adequate amount of attenuation. However, the passive DI fails to simply supply a properly adapted signal. If you’re goal is to use the amps and pedals as signal processors, the adapter ought to facilitate that work, not pile on it’s own distortion.

Relative Phase

In applications where the originally recorded signal and the re-amped signal will be used in the mix together, their relative phase is an important tone-shaping factor.

There are two great options for addressing the relative phase of these two signals (options that put a polarity switch to shame):

  1. Speaker to mic distance. For many signals, moving the microphone back and forth along the pick-up axis will reveal a dramatic range of tonal difference. This can be particularly apparent with signals that have complex midrange harmonic content.
  2. Phase ‘alignment’ tools, like the IBP from Little Labs. Used as the re-amping adapter or after the mic pre-amplified return, these devices provide sweepable electronic control over relative phase. This allows the mic to stay in the spot you liked the most.

Regardless of your choice of tool, remember that relative phase is a subjective tone control in this setting. Don’t think about what’s right or wrong.

Either or Both?

Sometimes it can be difficult to decide whether the original signal should be used in combination with the re-amped signal. In these cases there’s usually something unique about each signal, but they may not be working together well.

This conflict can often be resolved by creating more contrast between the original and re-amped signals. On keyboard tracks, for example, I will frequently make significant, crossover-style EQ choices that allow me to more subtly combine the unique elements of each signal type.

Another technique that can be used with remarkable ease is one I dubiously call “Sum and Amp-ness”. I think it kills for gritty bass, particularly with tight, close drums.

  1. Use a DI bass right up the middle of your mix. Get it sounding great, and setup a re-amp path;
  2. Setup a nicely overdriven bass tone on an amp. Somewhere in signal flow, HPF this path in the 300 – 500Hz neighborhood. I like to do it before the amp;
  3. Use the return from the amp just as you would use the ‘side’ component of a mid-side mic array. For maximum sum and difference affect, mic the amp off-axis.

This set-up leaves you with strong, centered low frequency focus, but adds an interesting distorted ‘width’ component. Try it out in mono-tending drum and bass situations.

Finally, don’t be afraid to let the re-amp path hang out in input monitoring while you mix. There’s no real reason to record it until you’re getting close to printing mixes. It’s incredibly easy to make changes as long as it’s all still live.

Rob Schlette

Rob Schlette

Rob Schlette is chief mastering engineer and owner of Anthem Mastering, in St. Louis, MO. Anthem Mastering provides trusted specialized mastering services to music clients all over the world.
  • Frank Nitsch

    Hi Rob,

    “reamping”, one of my favorite topics in the recording business. Thanx for this article about it. I would like to add a few comments about my experience with reamping.

    First of all I started after reading about the fundamentals of reamping. Since I didn’t have a reamping box in the beginning, I thought my passive DI box would do the job. I have read a lot of forum entries and seen a lot of youtube videos, in which people mentioned and presented that a passive DI box works fine for them. However I had no luck with it. I received a massive amount of noise while trying to reamp into a guitar amp in distortion mode. Also the signal wasn’t as strong compared to the guitar plugged into the amp directly. Maybe ballanced outputs on an audio interface or just higher output than my interface could catch up with this issue. For me it didn’t work. Therefore I bought the Daccapo reamping box from Palmer, which in my opinion is great value for the money. It features some option switches I didn’t find on the other reamping boxes around. Using it solved the level problem partially. The level was stronger than before, but still not 100%. I discovered that I had to make sure that all level controls in the playback path of the DI track need to be at full scale. First I missed the panning law, which reduced the level, of the signal, which was hard panned left. It was set to -3 dB for left and right panning. Either setting back panning to 0 dB or switching the pan law to “do nothing” for this track gave me the maximum level, which I adjusted on later to match the guitar’s direct signal.

    Another challenge is editing. Joe Guilder recently wrote a refresher on the basic recording and mixing steps. No magic, but very reasonable reminders to take into account. He makes the point that you should finish editing track before you move to the mixing step. And here is the problem: you recorded one DI track of a guitar and the amp signal, which you may want to use for mixing, either in addition to the reamped signal, without reamping at all, or not at all. Let’s assume you need to do some edits on the guitar track. Maybe there is some unwanted noise you want to get rid of. Maybe some fades and volume adjustments. Normally you would use your DAW’s functionality for cutting, trimming, etc. But keep in mind: if you reamp the signal – maybe even multiple times -, you have to apply the same edits on these takes, too! How to achieve that? I found out that the best thing to do would be to use level automation for it. If you just wanted to cut certain sections of a take you could also use an automation curve controlling the “mute” button.

    The advantage of this approach (at least in Reaper) is that you can copy automation curves/envelopes and paste them to any other track. I usually create a mute envelope on the amped track and copy it to the DI track. The reamped track usually will be ultra-clean. ;-) You can also copy the envelope to the reamped track, if that sounds better at the end. The advantage of using the mute function instead of the level for automation is that you could still use level automation to adjust the signal strength for certain parts of a song. Changing the level of the DI track has the same effect as turning the volume poti on the guitar. It gives you the chance to play with this variable after recording the guitar and the resulting sound from the amp can have quite some nice options in store for you.

    How do you tackle these challenges in the reamping scenario?

    Take care

    Frank

    • http://www.anthemmastering.com Rob Schlette

      In cases where you want to add the re-amp path (and continue to use the source track within a mix) I would recommend using a pre-fader aux send from the source track to feed the re-amp setup. Any DAW (including Reaper) will give you this facility. Then you you won’t have to jump through any of those gain staging hoops.

      Your two biggest noise issues will be unbalanced cable length and proper grounding. I’d suggest keeping you cable run from the re-amp adapter to the amp as short as possible (certainly less than 5′). As a default, the audio ground from DAW output to amp input should not pass (it should be lifted). If those two items don’t get things nice and quiet, the source track is likely the problem.

    • Frank Nitsch

      Hi Rob,

      well, the cable from the reamping box to the amp is about 1′ anf ground is lifted. Still there is some noise floor when reamping into a high gain distortion preamp. I’m not using really high gain distortion as this is most times counterproductive for recording an mixing, but there is more noise than coming from the guitar directly. Using a slight noise killer like ReaFIR in Reaper let’s me get rid of this before sending the signal to the reamping box. I made a test and recorded the shorted input, then fed that to the reamping box. The noise must be the quantization noise, which has a really low level recorded at 24 bit, but the distortion preamp amplifies it to some noticeable level. Have you tried something like that and didn’t you experience some noticeable noise? I’m talking about distorted guitar sounds for Metal style music.

      I know of the pre-fader option for sending the reamping signal out to the hardware, but still I prefer the post-fader way. Why? I want to provide exactly the same signal level the guitar produces to the amp. I cannot adjust the small pot on the reamping box fine enough to match that level, so I did that in the DAW while having the reamping box pot set to max. This way I have a fix level adjustment for my DI tracks, which is preserved in a track template. Recording to this track and playing it back guarantees that the level is just as it should be.
      Furthermore: when sending the DI signal out pre-fader, how would you apply a level envelope or mute envelope for automating the edits as described in my earlier comment? It would mean to apply them to the re-recorded signal track, which of course would also work fine.

      Thanx & regards

      Frank

    • http://www.anthemmastering.com Rob Schlette

      You can rest assured that it isn’t quantization noise. By definition, it would be impossible to amplify quantization noise (from 24-bit audio) to an audible level because it is so many orders of magnitude less than the white noise floor of your system and would always remain so (at any absolute level).

      Your re-amp setup shouldn’t have any more inherent noise than a guitar/amp tracking setup with the same guitar and amp. If that’s what you have, you’re rockin.

    • Frank Nitsch

      Well, that sounds as if I should do some more tests with variations of my input, output and cabling options. Either I can follow up on this conversation with some new details (which I pretty sure had already but didn’t write down), or I find a way to get rid of the low level noise in my setup without DAW plugins. Be sure to hear back from me later.

      Thanx so far for your valuable input. :-)

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