Should you do this mod?

Whether or not you should modify your own ribbon mic depends largely on your answers to 2 questions:

Can you hear a difference in the samples? If not, then you’re unlikely to gain any useful improvement to your recorded sound by modifying your mic.

Are you comfortable with a screwdriver and pliers? You can easily destroy the ribbon. If that prospect upsets you, then it’s probably best to leave your mic alone.

Transformers

As I mentioned in part 1, an upgraded output transformer can also improve the sound of a low-end ribbon mic. The transformers most commonly recommended for this mod (which I’ll demonstrate in a future article) are:

• The Lundahl LL2911, available from Kevin Carter’s K&K Audio
• The Cinemag CM-9888, available directly from Cinemag
• The EDCOR RMX1

Here are some basic instructions for upgrading the transformer (from Jon Ulrigg, who manufactures Shinybox ribbon mics.)

Michael Joly, a regular on the Gearslutz and Homerecording.com forums, also performs mods for most of the cheap Chinese ribbon mics through his OctavaMod Shop. The site also has galleries and samples.

Ribbon mic resources

Finally, here are some helpful resources and ribbon-related DIY projects if you’d like to learn more about ribbon mics:

• Here’s a technical explanation of how ribbon microphones work.
• Instructions on replacing a ribbon, which would also be handy if you fancy building your own mic from scratch.
• Warren Dent’s cheap ribbon mic shootout offers sound clips recorded through several of the most popular low-end ribbon mics.
• The GroupDIY Mic Meta thread links to dozens of microphone related projects, many specific to ribbon mics.

Previously: Ribbon Mic Mod – Part 1, Ribbon Mic Mod – Part 2

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Methodology

I recorded each pair of clips below simultaneously, which makes A/B comparison easy: Line up the beginning of both clips in your DAW, and flip between them while they play. I choose this over a standard “before and after” approach because the performance in each pair of clips is identical, which makes it easier to concentrate on the sonic differences without being distracted by performance nuances.

I should note that this approach makes two assumptions:

• The unchanged stock mic ribbon has the same response as the modded mic ribbon: I’ve used these mics as a stereo pair in the past, so I know they were, for all purposes, identical. (In hindsight, I should have recorded an A/B clip with both mics before modding one, for comparison.)
• Phase anomalies are minimal: It’s impossible to completely eliminate phase effects when dealing with multiple mics. However, I took care to ensure the ribbon of each mic was exactly the same distance from the sound source. You can load the WAV files in a DAW yourself and confirm that the transients strike each mic coincidentally. Further, the characteristics of each mic are consistent across the samples below, even though I recorded different instruments, with different configurations. So it’s reasonable to assume that audible differences are due to the microphones’ properties rather than my recording setup.

Before / After Clips

I tried to represent both musical and percussive sources, as well as fast and slow transients. Note, though, that I haven’t applied any post-processing to the sounds. They’re rough … but accurate.

If you have difficulty hearing differences between each pair of clips, import the WAV files into your DAW, line them up to start together, loop a small section, and listen to each file 3 or 4 times before switching to the other. As your ears adapt to the similarities between each clip, the differences will become more obvious.

Acoustic Guitar – Hard strummed
This sample is both percussive and musical, to highlight differences in the modded mic’s transient response, as well as its broadband frequency response. Listen particularly to the lower frequencies.
  Stock mic – Acoustic guitar strummed [2.6Mb]
  Modded mic – Acoustic guitar strummed [2.6Mb]

Acoustic Guitar – Finger picked
This sample has much slower transients than above. Notice how the modded mic sample sounds less restricted.
  Stock mic – Finger picked guitar [2.4Mb]
  Modded mic – Finger picked guitar [2.4Mb]

Cymbals (crash, then ride)
In this sample, focus on the high frequencies. I find the differences obvious in the cymbal decay, where the stock mic exhibits some high frequency distortion. (Not necessarily a bad thing for a cymbal mic. In fact, I’d probably prefer the stock mic here for close-miking a hi hat.)
  Stock mic – Cymbals [3.8Mb]
  Modded mic – Cymbals [3.8Mb]

Electric Guitar
I played this on a Les Paul through a Peavey Classic 50 almost fully cranked, with just a hint of saturation. Personally, I think this sample illustrates the best use of a cheap ribbon mic: Loud guitar! The differences between each sample, though, are minimal.
  Stock mic – Electric guitar [2.3Mb]
  Modded mic – Electric guitar [2.3Mb]

Full Drum Kit
Finally, here’s a full drum kit sample. Listen for differences in the low bass (especially the kick drum,) and cymbal tails.
  Stock mic – Full kit [3Mb]
  Modded mic – Full kit [3Mb]

Observations

I wouldn’t call the change night and day. This mod certainly won’t turn an Apex or Nady into a Royer. But given the minimal effort required, I’d say there’s no question the mod is worthwhile.

As I noted, the changes to the mic’s response are most obvious at the ends of the frequency spectrum. The moded mic has a beefier bottom end, and a softer top end. Through the modified mic, acoustic guitar has clearer low-mids, kick drum has much more punch, and cymbal tails are a little less brash. High frequencies through the stock mic almost sound distorted in comparison.

Overall, the modded mic yields a slightly richer, less “pinched” sound.

Next, my Closing thoughts which you might find helpful if you’d like to try modding your own ribbon mic (even if it’s not an Apex 205)

Previously: Ribbon Mic Mod – Part 1

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• Remove unnecessary screening from the mic
• Replace the transformer

I recently performed the first modification on one of my mics, and left the other mic alone with the intent of doing a real A/B comparison. That is, with both mics on the same sound source, at the same time. Here, I’ll walk you through the mod, before discussing the changes I found in the mic’s response. (Note: I plan on performing the second modification, for further comparison, in the future.)

Background

The ribbon in a ribbon mic damages easily. One errant wind blast is enough to stretch or tear the ribbon. So the manufacturers of these cheaper mics include extra wind screening to guard the ribbon, knowing that many buyers are first-time owners likely oblivious to the care a ribbon requires. However, if you understand the mic’s delicate requirements, you don’t really need all the extra screens, and their effect on the mic’s response.

Modding your mic

Removing the screening is straightforward. (And it’s the easier of the two mods mentioned above, as it requires no soldering.) You’ll need:

• A Philips head screwdriver
• A pair of pliers
• Possibly a pair of metal snips or wire cutters
• Optionally, some foam
• A clear work area

Step 1: Access the ribbon assembly

The Apex 205 has a 2-part casing: A mesh basket (the top) which houses the ribbon and ribbon motor, and a blue canister (the bottom) which houses the transformer and electronics.

To disassemble the mic, first remove the 3 screws holding the mesh basket to the base – one under the engraved figure 8 and two on the back (marked “a” in the picture below. Click the image for a closer view.)

The ribbon housing is attached to the inside of the mesh basket by the remaining screw and the top of the mic stand mount. Unscrew both of these (marked “b”,) and you can remove the ribbon assembly from the case.

Step 2: Remove the wind shields

The ribbon assembly consists of 3 main parts: The saddle (my name for it) which is the metal frame to which the transformer is also attached; The wind shields, which you’ll be removing; and the ribbon motor.

There’s no trick to removing the shields. They’re attached to the ribbon assembly with a few small nuts which loosen easily (though may require gentle coaxing with needle nosed pliers to get them started.)

Working slowly so as not to agitate the ribbon, first remove the nuts that hold the ribbon motor to the saddle.

Then, remove the nuts that hold the screens in place, and slip the screens off the ribbon assembly.

You may need the pliers again to loosen the barrel nuts holding the top screen in place.

With the screens removed, you can reattach the ribbon motor to the saddle. (You don’t need to replace all the nuts that held the screens in place, though you can if you want.)

Step 3: Remove mesh screening

This step is a little trickier, and messier. Truthfully, I’m not convinced it’s necessary. I can’t tell the difference in sound between a 205 with and without the inner basket mesh. (Though this is not true for the wind screens, above. Those metal screens definitely affect the sound.) So if the sight of wire cutters in the picture below makes you anxious, you can skip this step.

To remove the mesh, press gently on the outside of the basket just enough that the mesh comes away from the rim on the inside. Slip a screwdriver under the inner mesh and pry it away.

Depending on your mic, there may be two layers of mesh. You can remove one or both of these. (Again, in my experience, the choice makes minimal, if any, difference to the final sound of the mic.)

The mesh is affixed to the outer basket with epoxy, though how firmly differs from mic to mic. Sometimes both inner mesh screens peel off easily, sometimes you need some clipping to help them along.

Step 4 (optional): Pad with foam
This step is optional, though in my opinion worthwhile. Using a loose foam, like the kind used to pack electronic devices, fill the spaces between the ribbon assembly and saddle, and the space around the transformer in the base canister. This should dampen the effect of mechanical vibrations, such as footfalls near the mic stand, and help reduce resonance in the canister.

Step 5: Reassemble
In case you’ve lost your orientation, the picture below shows the front face of each component. The saddle mounts, figure 8, and Apex logo should all line up.

Re-affix the basket to the saddle (the green “b” screws in the first image above,) then attached the basket to the base (the red “a” screws above.) And that’s it. Your mic is now ready!

Your newly modded microphone

The mic is good to go at this point. However, because you removed most of its built-in wind protection, you’ll need to take some new precautions:

• Avoid windy locations: You’ve had the mic apart, and seen how delicate the ribbon is. Image what a stiff gust of wind, or blast from a strong fan, would do to that now-unprotected ribbon.

• Use a pop screen as much as possible: Obviously, you’ll need a pop screen when recording vocals. But other instruments can generate blasts of air strong enough to damage the ribbon. In particular, the speaker motion from a loud guitar amp, especially on hard, sharp sound, moves enough air to tear the ribbon.
• Don’t move the mic too quickly: When transporting the mic, or moving it about your studio, don’t make abrupt movements. Better yet, keep the mic in its protective bag unless you’re recording.

And finally, the obligatory disclaimer: This will void your warranty, and you can destroy your microphone if you’re not careful, both while performing the modification and in regular use thereafter. I won’t be held responsible if you attempt this procedure on your microphone, and damage it. I’m happy to offer suggestions or assistance if you run into difficulties (leave a comment, or email me: des @ hometracked . com.) But what you do to your microphone is all on you.

Next: Audio samples comparing the modded and unmodded mics

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Spring and plate reverbs are the easiest designs to implement. Though depending on your skill with a soldering iron, you can also build an electronic reverb. And capturing the natural ambiance of a space, with a speaker and mic, offers almost unlimited possibilities.

Here’s a collection of links to the Web’s best plans for these homemade reverbs:

Spring Reverbs:

• The most comprehensive design I’ve seen: The Slinky Spring Reverb.
• Some variations on the Slinky design, including a stereo spring reverb.
• A cabinet-style spring reverb for guitar.
• The $2 spring reverb, built from a toy echo mic.
• And finally, a no-frills dirt cheap design.

Plate Reverbs:

• The definitive plate reverb design comes from TapeOp magazine.
• A no nonsense approach, from a poster on the electro music forums (copied here because the site is frequently unavailable.):

I got a sheet of steel, about the size of a very large refrigerator, this was about 1 X 2 meters more or less. I built a wooden frame of 2X4s. Two holes were drilled near the top of the plate and it was suspended to hang on two wooden dowels through rubber grommets.

I took an old 12″ speaker and cut the metal cage off of it and trimmed the speaker cone so as to only have about 1″ from the driver. Then I built a wooden cross member across the plate but not touching it to hold this speaker and glued the shortened cone to the plate. I attached a contact microphone to the plate. I drove the plate through a 50 watt amplifier connected to the speaker (glued to the plate) and took the signal from the contact mic. The placement of the mic is determined by experimentation. I built a simple wet/dry mixer. In those days people built their own circuits. Today I’d buy the mixer.

This entire apparatus was in the basement below my studio.

Electronic Reverbs:

• A collection of schematics for various reverbs.
• Many effects pedal schematics, including a few reverbs.

Natural reverbs:

• Electronic Musician’s Keeping It Real article describes some great approaches to capturing natural reverberance (including a washer or dryer, and an old Gibson guitar.)
• Upload an audio file to Silophone, and hear how it sounds played through speakers in a grain silo.

Homemade noize, a growing collection of DIY projects and software plugins, mostly aimed at amateur recording enthusiasts.

And Spinmeister’s Extreme Mixer (eMXR) site, which focuses on online collaboration and remixing. From the site:

Long held business models for recorded music are crumbling not only because of file sharing, but also because of the increasing supply of free or inexpensive music of excellent quality created in homes rather than recording studios. Long held country specific IP (intellectual property) and licensing models are made obsolete by the global reach of the Internet for music makers and consumers alike.

On that topic, here’s a chilling little anecdote from Seth Godin’s blog about
choosing music in a world with limitless supply

It’s almost impossible to buy music with no frame of reference. There were no hits, no recommendations, no “if you like x, you’ll like y”. I realized that the time it would take to decide if I liked an album was probably worth more than the $3 it would cost to buy one–in other words, not even worth it for ‘free.’

The Time Correction Wiki: Described as a website “dedicated to the study and practice of time correction techniques in audio engineering and music production.” I didn’t realize the field warranted such in depth examination, but then I also wasn’t aware of the distinction between perfect and irrational looping.

Which DAW is best for you?: It’s ad-ridden, but this article on Digital Pro Sound highlights the similarities and (rapidly diminishing) differences between 5 of the main DAW software pacakges: Protools, Acid Pro, Audition, Sonar, and Cubase.

Most of the cheaper ribbon mics are manufactured in China. Among the most popular: Apex, Shiny Box, and Nady. I have a pair of Apex 210s that make great drum “underheads” (as recently discussed on the TapeOp messageboard.) The rolled-off high frequencies yield a much more controlled cymbal sound, a plus for anyone recording drums in an untreated basement.

If you’re unfamiliar with ribbon mics, here are two great magazine articles describing how they work, and when you might want to reach for one:

From Electronic Musician, Ribbon Revival:

The benefits of ribbon miking are often characterized as a smooth and natural timbre without sibilant highs, full low-end response at any distance, and high-SPL handling. Low noise and superb transient response are additional benefits, especially when a ribbon is paired with a quality microphone preamp. (See the sidebar “Preamps for Ribbon Mics.”)

From Mix Magazine, Ribbon Renaissance:

The qualities that make them prized are many: “Warm,” “musical” and “syrupy” are words often used to describe a ribbon mic’s trademark sound, which is attributed in part to a gentle proximity effect that becomes pronounced within a few inches of the mic, as well as an inherently flat frequency response with a smoothly attenuated top end. They’re naturally bidirectional, perfect for both mid/side (M/S) and Blumlein stereo recording techniques. In addition, the low mass of a ribbon diaphragm allows for fast transient response. Ribbons also offer a wide dynamic range, useful on everything from capturing low sounds from stringed instruments to handling extreme SPLs at high frequencies, making them an ideal choice for miking brass and percussion.

If you’re handy with a soldering iron, the Chinese mics also lend themselves to some easy modifications that can dramatically improve their sound. The easiest involve removing the internal mesh, and upgrading the microphone’s transformer.

More details here and here

The transformer mod is straightforward. two wires on primary, two wires on secondary. Desolder, mount new transformer, resolder.

On the Cinemag transformer, the primary pair is red/brown wires, the secondary pair is the orange/yellow wires, with the white wire connecting to ground.

So the upgrade is simple as desoldering the existing wires, mounting the new transformer, and connecting the new traffo wires to their appropriate spots.

Typically, the plate is a large sheet of steel suspended in a tubular steel frame. In theory, the plate simulates a large concert hall, or church, with a decay time of approximately five seconds at approximately 500 Hz. A driver attached to the plate excites it, and as the sound waves travel through it, the plate flexes. The plate’s motion is then picked up by one or two contact mics, and added to the dry signal at the mixer.

The project isn’t for the timid. But if you’re handy, and have a large sheet of steel lying around, an authentic plate reverb could add a distinctive touch to your recordings.

Previously: Create your own reverb

… for all its wonders, digital reverb is not indispensable, nor is it always the best way to impart a convincing sense of space to your recordings. Does anyone really think that, for example, Miles Davis’s Kind of Blue would sound better if PCM70s had existed in 1959? Would Led Zeppelin’s “When the Levee Breaks” still hold up today as a zenith of rock drum tones had the kit been close-miked and swathed in digital reverb?

Hot-water heaters, it seems, make great reverb tanks, and a washer or dryer can make a distinctive-sounding reverb chamber.

This isn’t necessarily bad: Some rooms have a great ambience which adds natural depth to a mix. But the room sound in smaller spaces, like most bedroom and basement project studios, usually hurts rather helps a track. Ethan Winer outlines the main issues – comb filtering and room modes – in his article on recording spaces.

For several reasons, small rooms are especially harsh on vocals:

• Vocals tend to need compression, which raises the noise floor of a track and makes the room sound more obvious.
• The best vocal microphones have omni and cardioid polar patterns, so they inherently capture more ambience.
• Many singers like to stand a few feet from the microphone, allowing more of the room sound to leak through.

Enter the DIY portable vocal booth:

Douglas realized that for a microphone to sound good and tight you didn’t need to be inside a sound box – the microphone did. So, he built a simple 16” by 16” four-sided box out of foam core, lined it with acoustic foam (usually sold in 16 x 16 inch tiles), stuck his microphone inside, and recorded with it. Dubbed the VO Box, the results were stellar even in a “bad” room.

While the project as described is easy to build, you could probably simplify it even further by using a plain old cardboard box and rockwool or stiff fiber insulation.