Mic-ing stereo cab

[hydro]

Hi,

I got bi-amping working with my Mesa 4x12 cab and now have one head running through the left half, one through the right. Love the sound, but I am wondering how to best record it using a single dynamic mic (sm57 for example), or also for live situations where the guitar gets only one mic. Can you position it back a little and in between the left and right speakers?

 

[beaubrummels]

Re: Mic-ing stereo cab

I would pick the better sounding speaker as heard through the 57, find the sweet spot on that one cone, and go with that. Anything trying to get two speakers with one mic is going to sound dark and dull, unless it’s a really high-end studio recording mic.

 

[Empty Pockets]

Re: Mic-ing stereo cab

There's no point in running a stereo rig into one mic.

 

[ehdwuld]

Re: Mic-ing stereo cab

There's no point in running a stereo rig into one mic.

I was trying to find a nice way to say this as well

 

[CapoFirstFret]

Re: Mic-ing stereo cab

Several things to unpack here. I'm not an expert, but I've been doing this a while but feel free to take what I say with a grain of salt.

Bi-amping is not stereo. Also dual mono isn't stereo.

Bi-amping is a process of separating your signal by frequency and sending separate sets of frequencies to different amps and is very popular with bassists. Say, sending everything below 800Hz to one amp and everything above that to another to separate the highs and lows or mids and highs or whatever you want to do. In this scenario, you could theoretically do it with one mic and be fine if you can find the right mic that can get the sound of both and balance them - although two microphones would be preferable.

Dual mono is a process in which you send the same signal to two separate amplifiers. There's a lot of great reasons to do this especially if you just want a bit of a bigger sound or want to blend two different amp sounds. In this setup, assuming the amps don't sound incredibly different, you would be fine just micking one of them since they essentially get the same sound.

Stereo means that the different signals are getting different information. In order to be truly stereo you need some way and reason to separate the signal into true stereo. Usually a delay, reverb, or modulation. In this scenario either side doesn't get the same signal and is often done to increase the effect of modulation or wideness of the sound. In this scenario, because the different sides get different signals, you absolutely have to use two different microphones and when you put them through the PA they need to be panned left and right in order to maintain your true stereo effect through the PA.

I really hope this helps and clarifies a few things.

 

[beaubrummels]

Re: Mic-ing stereo cab

Yeah but electric guitar only has a range from what, ~500hz-4khz, so I’m not sure how much benefit there is to splitting that and recombining it into one mic. You’re losing frequencies on the crossover and introducing phase issues from two speakers on top of that, combing out more frequencies, into the one mic.

 

[NegativeEase]

Re: Mic-ing stereo cab

OP, this is not stereo mic'ing, this is finding the best placement to blend the 2 sound fields -super common -not magic. I do this all the time in the studio when the artists doesn't prefer post mixing of the sound but rather capturing what they hear when standing in their favorite proximity -or when there is a shortage of channels -like a live recording. Ignore the previous comments, they must be thinking of some other scenario.

The SM57 is a Cardioid pattern dynamic mic, and you have to use this to move the mic between the two speakers and listen -unfortunately because it's cardioid, you have some side rejection properties to contend with meaning that you can't obviously close mike off-axis just off from the cone -like most would suggest if you used 1 mic for 1 speaker -especially when using any dynamic mics where high SPL is not a concern. Instead you have to back off the cab a foot of so in order to start to get a blend of the 2 speakers -this will start to bring in some of the sound of the lower end of the cabinet sometimes, and certainly start to bring in reflections in the room when you have stops or spaces between notes -so you have to contend with more variables.

With effort, there is no reason you can't capture the blend you want from one mic -I can name 100 classic albums that did this exact technique -especially when track count was a concern in the tape days -especially changing the axis of the mic to bring in more or less rejection from one of the speakers without pulling more distance form the cab.

 

[CapoFirstFret]

Re: Mic-ing stereo cab

Yeah but electric guitar only has a range from what, ~500hz-4khz, so I’m not sure how much benefit there is to splitting that and recombining it into one mic. You’re losing frequencies on the crossover and introducing phase issues from two speakers on top of that, combing out more frequencies, into the one mic.

If you split it correctly you shouldn't use any frequencies in the crossover, especially if you choose the right point. Bassist particularly like it because it allows them to mix their high end and their low end more precisely. I used a bi-amp rig for a while. It was just too much trouble after a bit though. I can't think of a guitarist that does it at all. I only mentioned it because the OP used the term "bi-amp" when I'm fairly sure they meant stereo.

 

[hydro]

Re: Mic-ing stereo cab

Yes, I probably should have clarified: the *cab* is stereo, as in it has two 4 ohm inputs which can operate each side of the cab independently and can be used for stereo applications like ping-pong delay, etc. But I'm not trying to get a stereo result at all - I get that I can't do stereo with a single mic. I am using it to blend two amp sounds, bi-amping, with a Radial Big Shot aby. I'm hoping to get the best blend of the two heads in the single SM57 dynamic mic I am using. One head is a silver jubilee set to have a little more high end and gain, the other is a custom amp that has a lot more headroom and low end. I'm not splitting frequencies but blending the sonic characteristics of the two amps into a single cab, which happens to split left/right vertically. This is really just for scratch recordings but might have applications if I use this same rig live as well, regarding mic placement by the sound man, who is likely to only give me one mic.

Several things to unpack here. I'm not an expert, but I've been doing this a while but feel free to take what I say with a grain of salt.

Bi-amping is not stereo. Also dual mono isn't stereo.

Bi-amping is a process of separating your signal by frequency and sending separate sets of frequencies to different amps and is very popular with bassists. Say, sending everything below 800Hz to one amp and everything above that to another to separate the highs and lows or mids and highs or whatever you want to do. In this scenario, you could theoretically do it with one mic and be fine if you can find the right mic that can get the sound of both and balance them - although two microphones would be preferable.

Dual mono is a process in which you send the same signal to two separate amplifiers. There's a lot of great reasons to do this especially if you just want a bit of a bigger sound or want to blend two different amp sounds. In this setup, assuming the amps don't sound incredibly different, you would be fine just micking one of them since they essentially get the same sound.

Stereo means that the different signals are getting different information. In order to be truly stereo you need some way and reason to separate the signal into true stereo. Usually a delay, reverb, or modulation. In this scenario either side doesn't get the same signal and is often done to increase the effect of modulation or wideness of the sound. In this scenario, because the different sides get different signals, you absolutely have to use two different microphones and when you put them through the PA they need to be panned left and right in order to maintain your true stereo effect through the PA.

I really hope this helps and clarifies a few things.

 

[hydro]

Re: Mic-ing stereo cab

No, I did mean bi-amp. Using two different heads, same signal, different tones/settings on the two amps. I think for example, Matt Pike does stuff like this where he runs a low end amp fairly clean and a higher gain amp with more dirt. I'm just doing it in one cab instead of two, since my cab has the option of dual inputs which basically split it into two 2x12 vertical cabs. It actually sounds REALLY good, which is why I'm hoping to figure out how to best catch the sound with a single mic.

If you split it correctly you shouldn't use any frequencies in the crossover, especially if you choose the right point. Bassist particularly like it because it allows them to mix their high end and their low end more precisely. I used a bi-amp rig for a while. It was just too much trouble after a bit though. I can't think of a guitarist that does it at all. I only mentioned it because the OP used the term "bi-amp" when I'm fairly sure they meant stereo.

 

[hydro]

Re: Mic-ing stereo cab

Thank you sir, this is just what I was looking for. I think my post confused because I mentioned a "stereo" cab. The cab back panel says "Split for stereo or bi-amp" so I probably should have been more clear. I'll give your technique a try!

OP, this is not stereo mic'ing, this is finding the best placement to blend the 2 sound fields -super common -not magic. I do this all the time in the studio when the artists doesn't prefer post mixing of the sound but rather capturing what they hear when standing in their favorite proximity -or when there is a shortage of channels -like a live recording. Ignore the previous comments, they must be thinking of some other scenario.

The SM57 is a Cardioid pattern dynamic mic, and you have to use this to move the mic between the two speakers and listen -unfortunately because it's cardioid, you have some side rejection properties to contend with meaning that you can't obviously close mike off-axis just off from the cone -like most would suggest if you used 1 mic for 1 speaker -especially when using any dynamic mics where high SPL is not a concern. Instead you have to back off the cab a foot of so in order to start to get a blend of the 2 speakers -this will start to bring in some of the sound of the lower end of the cabinet sometimes, and certainly start to bring in reflections in the room when you have stops or spaces between notes -so you have to contend with more variables.

With effort, there is no reason you can't capture the blend you want from one mic -I can name 100 classic albums that did this exact technique -especially when track count was a concern in the tape days -especially changing the axis of the mic to bring in more or less rejection from one of the speakers without pulling more distance form the cab.

 

[Demanic]

Re: Mic-ing stereo cab

Maybe you should try a condenser mic about 6' away from the cabinet.

Sent from my Alcatel_5044C using Tapatalk

 

[LLL]

Re: Mic-ing stereo cab

Yeah but electric guitar only has a range from what, ~500hz-4khz

If the guitar's low end started at 500Hz, there would be no low end; it would be all mids and highs.

Typical guitar speaker (final EQ filter for a rig) is more like ~75 Hz - 6 KHz. Some go to ~55 Hz.

Standard/concert-pitch (A=440Hz) tuned guitar, E is at about 83 Hz.

 

[beaubrummels]

Re: Mic-ing stereo cab

...but the usable response of an SM57 starts around 100hz. It drops off below that. So your not getting much guitar low end goodness with a 57 in the first place. But the point is, splitting the signal, pushing through two different speakers, and recombining into one mic is losing more frequencies. A nice studio-grade condenser would at least capture the room sound similar to what your ear might hear, but that’s the best you can do.

 

[El Dunco]

Re: Mic-ing stereo cab

I don't think there's a good way to do it with one. You're really better off with two phase coherent mics.