Podcasters Secret Weapon

10/20/2021

If you're a podcaster, voice actor, or live streamer, especially On-Air, and you use microphones like the Shure SM7b and others that are known to have extremely low output, the Coda MB-Stealth mic pre-amp promises to deliver +28 dB of clean, high quality gain with very low self noise.

Have you ever wondered how podcasters and professional voice actors get that 'Pro" sound to their voice? They start by using professional quality microphones designed for voice to begin with. One of the world's most popular mic's is the Shure SM7-b dynaminc microphone. This is probably one of the world's most recognizable microphones because of it's distictive shape and style. Unfortunately, it's also one of the lowest output microphones. This means that the actual output in volume is incredibly low and that means you have to turn up the volume on your audio interface or mixer to make up the difference.

In theory this is no problem but, in practice, most gain input stages on mixers and audio interfaces are not designed to be run 'wide open'. By having to turn up the microphone all the way, you start to introduce excessive noise into your audio path. This is where the MB-Stealth comes into play. This Stealth promises to add an extra 28db to the microphones output, allowing you to run your inputs on your audio interface or mixer back down into the range they were designed to be the quietest in.

All this sounds great but, if the 'in-line' pre-amp adds additional noise into the audio path, we are right back to where we started. The Coda MB-Stealth by Coda Music Technologies is am "in-line" Mic Preamp that simply plugs into your exsiting dynamic microphone. This claims to supercharge your vocal mic with substantially more headroom and transform your current podcasting mic into a richer sounding vocal powerhouse. The question is, does it?

First, we setup a test to determine just that.Its important to understand that any test that has changing conditions would be 'subjective'. Meaning, if I just set up our Shure SM7-b and talked into the microphone, and then inserted the MB-Stealth into the signal path and did the same thing, there would be no definitive way to determine rather the MB-Stealth adds noise or not.

The Test:

So, instead, we setup a Yamaha reference monitor and set its controls at what is called 'unity gain'. This means that the incoming signal is not being changed as in comes into the monitor. Nest we setup our Shure SM7-b on a mic stand and pointed it at the Yamaha monitor speaker in our isolation booth here at the studio. This allows us to block out all the outside noise that is likely to skew to the test. Next we ran a 1khz test tone through the monitor and recorded the result into our DAW and measured the result. This was the 'control' for our test as whatever is in this recording will also be in our next test. This will allow us the accurately measure the difference.

Next, we insterted the MB-Stealth into the signal path by plugging it directly into the Shure SM7-b and turned on our audio interface's phantom power. This is how the Stealth gets its power to operate. The interface sends the phantom power up through the mic cable and powers the device. This is also how most all other in-line mic preamps work as well. From here we simply repeated the same test under the same conditions and then measure the result.

The Result:

After several tests with both the Shure SM7-b by itself and several with the MB-Stealth inserted into the signal path ( to reduce variables ) the test were conclusive and consistent. The MB-Stealth consistantly increased the gain of our Shure SM7-b by it's stated 28db of range. In addition, the Stealth did not change the actual frequency of the incomming signal in any way. All of this for less than 1/2 of a db in additional noise. All mic pre-amps of any kind add some measurable noise simply by virture of the electronics used in the device. So, there is no free lunch, ALL things make some noise. But this make very little. In fact, it's one of the quietest in-line pre-amps wev'e tested to date.

Conclusion:

If your looking for a way to make your 'low output' dynamic vocal microphone ( this cannot be used on powered condensers or some types of ribbon mic's ) then this pre-amp should definitely be on your short list! It adds a full 28db of clean, clear gain to microphones that have notoriously low output and can even be used on mic's like a Shure SM78 and SM57 as this really allows these microphones to shine! Check it out here: https://amzn.to/3liKPT0