Review -12 Gauge Microphones

This Review is aimed to cover aspects of the Red, Green, and Blue Microphones from 12 Gauge Microphones. In this review I am aiming to cover the following topics:

• Build quality, presentation and aesthetics
• Polar pattern accuracy and frequency response, including the differentiation between two microphones of the same model (green and blue)
• Conclusion

Out of the Box

Upon receiving the mics (which was quick considering they were from the US and I am in the UK, took about 9 days, and Brad, the maker, was extremely helpful in getting them to me ASAP) I was pleased them well packaged in a suitable sized box with good protection against transport. On opening I found the microphones contained within a well made solid pine box witch then houses each of the microphones in their own individual screw cap plastic containers with their model and build number clearly displayed (a nice touch). As well as a couple of merchandise stickers, and lets be honest…Stickers are awesome.

Individual Microphone Inspection

Lets start with the Omnidirectional Red:

Now with all of these microphones the build quality is consistent, considering each one is hand made and consists of very few components it gives the microphone quite a rugged build. I am fairly confident that these mics could take quite a few Knocks and still work.

The red is slightly shorter than the other blue and green models, as it has no need for the cancellation slots behind the mic capsule. other then that not much can be said at this stage. Its a spent shotgun cartridge…which is now a mic… and I think that’s cool.

The Green

At the moment I think this is the favorite for me of the three models.

The cuts made into the top of the cartridge have been well executed and nicely finished with a file, how these affect the microphone in regards to making it cardioid will be tested later in this review. It feels solid, and again could take a few Knocks, the grill placed behind the capsule is even pretty tough, these mics are made to last.

The Blue

This mic, slightly shorter than the green has been designed for High Spl situations such as drums, guitar cabs, etc.

With an additional slot cut behind the capsule it makes me think this is intended to have a narrower polar pattern with better rear rejection. Due to this additional slot it may make the brass slightly weaker in places and more susceptible to dents and bending, but time shall tell.

Otherwise the quality of the build is high making for a slightly less sturdy but still drop-able microphone, which for clumsy people like me is always an important thing to take into account.

Now The Nerdy Stuff

The Polar Pattern

For the people that don’t know what I am talking about, a polar pattern is basically the area in which a microphone collects its audio from. The information can be show in a 2D diagram (sometimes 3D) to help engineers decide on microphone placement and type when working with different instruments and situations. For more info please click here 

THESE TESTS WONT BE SUPER DOOPER LABORATORY ACCURATE!

Now, the normal test for finding a polar pattern is to place a microphone at 90 degrees about 30cm from a speaker creating a tone or white noise. You then rotate the microphone making sure to keep the capsule on axis/alternatively you could rotate the speaker  around the microphone(almost like a satellite round earth making sure to keep the speaker always at 90 degrees to the mic)  but this is trickier as speakers are often heavy. In industry this is often done in an anechoic chamber (a completely dead space with no room reverberations) so as to get the most accurate results possible. I don’t have one of those…

Once you are set up, you measure the variations in audio level as you rotate the microphone. (for my example I will be using Pink noise to give an average SPL) so in theory if using a cardioid microphone you should see a significant drop in level as you turn the microphone at 180 degrees from the speaker, as you approach the 360 mark the level should slowly rise. If you are using an omnidirectional microphone the audio level should stay the same throughout the rotation.

Ideally you also require a completely flat frequency response speaker so that you can check the microphone accurately at different frequency sine waves making for a more accurate polar pattern graph so as to show how the microphone reacts at different frequencies. However these speakers are expensive…. I don’t have one of these.

So for that reason I will be simply using pink noise at 60dB, through an average speaker, making note of variations in dB level changes as the microphone capsule is rotated on the spot through 360 degrees; so as to give a fair estimation on the polar pattern. Pleas note, these measurements are not super accurate, they give an idea of what the microphones are like to work with. I used RoomEQWizard to create both the noise, and monitor dB levels as the microphone was rotated.

The Results!

The Red:

Polar pattern represented by Red line

Not bad for an omnidirectional, I was expecting more rear rejection, so was pleasantly surprised that there was no more than 3dB loss

The Greens:

Polar Pattern represented by green line

 The Greens both showing a good cardioid pattern; one of them seems to have more rear rejection than the other by about 3dB, when compared to the red however it is made very clear that there is a good amount of side and rear rejection from both, which is what should be expected. I’d like to conduct a test of Polar pattern using sine waves to see precisely which frequencies are rejected the most and at what angle.

 The Blues:

Polar Pattern

Both the Blues showing pretty similar results here, I expect it is due to the slightly higher level of quality on the rejection slits behind the capsules. I was finding that in comparison to the greens these mics have something like a -15dB pad build in so as to handle the higher SPL’s. A handy feature for guitar cabs and especially snare drums!

Frequency Response

Frequency response give engineers a means to see what a microphone may “sound like” enabling them to decide what the microphone may be well suited to recording, before they have even heard it. Often when a microphone is purchased a document will come with the microphone giving a frequency response diagram that is unique to that individual microphone (it can often vary quite a lot). This document will often also show the polar pattern. An example of this is shown below with the Sure SM58 which is designed for vocals in a live environment:

As you can see there is a 5dB boost which gently boosts the Highs with a slight cut at around 7.5KHz, this is to help sweeten the vocals as well as avoiding nasty feedback frequencies.

For this part of the review I must say that the following measurements will not be a true representation. In industry these measurements are taken within anechoic chambers using speakers with perfect flat frequency responses. Meaning that there are no room reflections, standing waves, early reflections, hums, buzzes, tweeting birds, noisy traffic, barking dogs, crying children… you know, those sort of things.

I have an alright speaker and an Omnidirectional measurement microphone, meaning that it is “designed” to have a very flat frequency response. I have no fancy room. The Control measurement will be taken using this microphone so as to give the reader a representation of the speaker that I am using. They can then take this into account when looking at the response of each of the 12 gauge microphones. the control will however be a representation of both the speaker AND the microphone used in the control. A frequency response of the soundcard used, has also be taken so as to calibrate the system.  I will be using RoomEQWizard to take these measurements.

The control measurement:

This shows the speaker and measurement microphones response placed at 30cm. as you can see there are various peaks and troughs to the speaker. with a variance of +-5dB.

The Red:

The relation between the Control and the Red. showing that the red has got a nice rise around the high mids, this is a characteristic you would often see with vocal microphones, but to be honest, I would try this mic on anything, because experimentation is always the key with new mics!

The Greens:

The relation between the control and the two Greens, and how their responses differ. which in this case is quite a lot in the high end. I’d imagine these be well suited to drum overheads, acoustic instruments, and generally a good all purpose microphone. But I’m going to try it on everything!

The Blues:

The relation between the control and the two Blues, and how their responses differ. These are very similar to the greens in response, the difference being the dB cut built into these mics.

All:

This graph shows all of the microphones together and how they relate to one another. The blues have been boosted so that they sit at the same level as the rest.

And this final graph shows the different results spaced apart for better viewing.

conclusion

These mics are pretty good! I think the quality and uniformity is fairly consistent considering they are hand made and only slightly machined. They perform exactly as you’d expect they have slight inconsistencies in the microphone characteristics; especially between my pair of greens, slightly concerning, but I would be interested to compare a few more with each so as to get a better comparison that being said, my solution, now that I know what each of the mics “sounds” like, I might use one of the greens for one thing but as they don’t sound the same I may not use the other. It makes for an interesting decision for stereo mic situations, however any issues between the two mics could be fixed with EQ.
At the end of the day there is no right or wrong about it, for me its just about what works. You could spend the same amount of money on 2 pencil mics and probably have something of a similar sounding quality or you could buy 5, 12 gauge mics giving you more flexibility and a better collection of mics in the cupboard. So far I am yet to be disappointed and if at any point I am, I’ll let you know. The review is ongoing. But so far no complaints.

Thanks for reading. Please get in contact if you felt this review was missing something that you wanted to know, and I will add it on.
Cheers