When mixing DI with mic'ed amp... Your approach?

[Schaaner]

After seeing some bass recording tutorials, I'm curious about your point-of-views on the following scenario and slightly complicated question.

Often, bass is recorded with a DI box on one channel and with a mic'ed up bass amp on the second one. Produce Like A Pro does that with a Sontronics MD-1B mic for example. In mixing, the DI gives the low-end (low-pass) and the mic'ed amp delivers the higher frequencies (high-pass).

I'm curious, because I often read opinions that some mic's are not suitable because of their lack of low-end, but then during mixing, the low-end of the mic signal is cut/reduced by some engineers. In the above-mentioned method: why would I not use something with more detail and less bottom-end (e906, SM57, etc.)? With the DI taking care of low-end, those mics would sound almost perfect right out of the box, no? What am I missing?

Thanks!

 

[seamonkey]

Bass is traditionally recorded DI - what a "producer" mic added that does nothing really.

Speed of sound in the air causes phasing problems when mixing mics and DI.
It has always been that way. Old recordings often used just one or the other. Usually just DI.

There are many VST plugins that will adjust for phase issues, or you can nudge the tracks yourself. But, turning a mic just a little bit new phase issues speak out. DI has the least chance of causing phase issues.

But EQ can and does also cause phase issues. Especially all the "analog plugins" as they are actual circuit emulations of the old gear. Part of that old sound is phase. Think wha-wha pedal that shows off phase while it sweeps the mids.

Take a single track and send it to two tracks one with heavy "analog" vst and the other with a linear phase VST, then compare them. Linear phase EQ can only exist in digital usually gives people what they really want in an EQ. Try DI with the right vst EQ.

 

[pfschim]

When I'm doing my own thing, I generally track with just a DI (lately a Noble for more colored, or Countryman 85 for clean/flat). But I have done quite a few tracks over the years with a DI and a Mic (usually just an SM57, set at an angle right at the edge of the speaker cone). This works fine too, at least IME.

When I am working for someone else, I bring my tools and make sure the engineer knows what I have available, but then I always just do my parts with the signal path they prefer.

Lots of ways to get a good track these days. Play around a bit and see how you like the various options. Also consider how the bass track will fit the overall production.

 

[silky smoove]

If someone comes to my studio to track bass I’ll usually plug them into my Heritage Audio TT-73 and then use its thru output to feed back to an amp that I’ll mic with a D87 or an SM7B. I’ll review the two signals and decide which I like more and go with that 99% of the time. The other 1% is a combination of not liking the DI or the amp and using the DI signal to reamp with a different amp/cab/mic arrangement, or in some very rare cases I’ll use both. If I use both I never do the one “DI for lows, amp for everything above the LPF” thing. Instead I’ll get the two signals as close to in phase as possible through a combination of good mic technique and Sound Radix Auto Align, find a balance that I like between the two and then get on with the rest of the mix.

 

[Joey lewis]

My diy version of this is to just di out my clean signal at the front of my board and take the di out from my amp at the end of my dirty chain, and blend them together in logic. Haven’t noticed any phase issues and it gets me a decent amp tone without shaking my house awake. I’m not in a doom band, don’t need a huge cranked room sound

 

[Ken Morgan]

Depends on what I’m after…for a modern-ish sound, I’ll DI with a Jensen equipped Radial, a Mesa Subway+ pre, or similar. For more traditional sounds, I’ll mic up with a pretty good LDC.

note: the other day I secured a VG+ all original 1964 Ampeg B15. Test tracked something, and am now going back redoing ALL bass parts on a private release CD.

it makes a difference

 

[Ender_rpm]

As you noted, the crossover point really is the key, as is the character of the two signals. If all you're doing is clean bass, there's not much difference in SI or mic other than ID is easier. IMO its when you're blending clean and dirty signals, or wet/dry, that the magic happens. In my own work, I usually run a clean DI and mic my slightly wound up tube amp, so I get clean low end with a grindy middle. If I'm using a cab with restrained low end, like a 210AV or other AMpeg-like 10" system, the additional lows from the DI is almost always helpful. But I also get really nice, if not as deep, sounds when I put a mic in front of my 15" loaded cabs (Peaveys) for rounder clean sounds. But thats really a pretty specifically "vintage" type sound Im going for there. Its all experimental, have fun with it.

But to the point- The 57 starts rolling off in the 100Hz region, as I recall, and a lot of mud builds up in the 250K region. So if you use the DI up to the roll off, and cut a lot of the lower mids off the mic, you're "scooping" the mid range but by omission, rather than trying to EQ it out. Another path to the same idea.

 

[Wasnex]

I generally prefer a clean, clear, and tightly focused sound, which comes from a DI and decent studio gear. A mic would be better if you use OD or if you are trying to capture a certain mojo from the amp.

An SM57 should work fine, and response will extend lower than the datasheet suggests if you place the mic close to the drivers. I am by no means saying this is the best possible mic, but if it's what you have...

The SM57 datasheet does not show the mic's proximity effect.

From SM57 User Guide (shure.com)
Proximity Effect

Unidirectional (cardioid) microphones progressively boost bass frequencies by 6 to 10 dB below 100 Hz when the microphone is at a distance of about 6 mm (1/4 in.) from the sound source.​

I doubt you will place the mic within 1/4 inch of the speaker, but probably close enough to fill in the low end a bit.

An SM57 would be good mic to blend with a clean DI signal. Use the SM57 for gnarly distortion and color, and the DI for low end extension and focus.

If I were mixing, I would consider frequency slotting, HPF/LPF, and time alignment.