Sunday, June 6, 2010

Shinybox Ribbon Mic Mod

If you happened to have a pair of Shinybox 23 ribbon microphones set up in front of you, like so:

...would you be able to tell which one had more clarity, a more open tone?

What if the mics were lit from the back, like this:

It seems pretty obvious that the mic on the left, which allows more LIGHT through, would certainly allow more SOUND through. This is accomplished by doing a few simple modifications, which I have photographed, and am putting up here.

First, a few notes about ribbon microphones: they are some of the most delicate and sensitive mics - a cough or a fast breath can rip the 2-micron-thick aluminum ribbon, which ruins the mic. Never blow into a ribbon mic ("Is this thing on? Fff! Fff!"), and always handle with extreme care. Keep them right-side-up or upside-down, NOT horizontal/sideways, as this will cause the ribbon to sag, and not work properly.

These large Shinybox 23 mics are generally the same mics as the Nady RSM-2, the Apex 210, the t.bone RB-500, and the Cascade Vin-Jet, with only very minor differences. The multilayered mesh headbasket can resonate or ring, adding an undesirable metallic haziness to some sources. There are several layers of nylon mesh which are added to avoid wind/breath damage, but they also attenuate the high frequencies, and add phase shift to the low frequencies. And at the front and back of the "motor" (ribbon-and-magnet assembly, the heart of the microphone) are metal "waffle" plates (high frequency resonators), added to provide an acoustical boost in the high end (presumably replacing what the nylon mesh lost), but these parallel plates also create some high frequency comb filtering.

If we promise to be careful with our microphones, we should be able to remove these multiple layers of problematic "help" without any adverse effects.

Here's what we'll need:

That's it? No special tools? No solder? That's right. Piece'o'cake.

Here's a shot of the 1/2" thick foam pieces with a tape measure, for their general size and shape.


What I'm shooting for here, is a full set of step-by-step idiot-proof instructions. Please realize that even though all of my pictures show only ONE hand holding the mic or hand tool, it is because my OTHER hand had to hold a CAMERA. USE BOTH HANDS WHEN DOING THIS MOD. There. Now we're idiot-proof. Not that you're an idiot, but if you were only JUST slightly BARELY considering RIPPING OPEN your ONLY super-delicate ribbon mic, a set of instructions like this might let you go ahead and do it.

SO DO IT.

First, unscrew both knurled round nuts by hand. Remove the 2 small washers. Gently spread open the yoke (the big "Y"-shaped piece), and remove it from the mic.


After moving those parts out of the workspace, use the pliers to loosen the double hex bolts on both sides. I'm calling them "double hex bolts" because they are 2 opposing bolts joined in the middle with a hexagonal head.


Finish removing both double hex bolts by hand, along with the 2 washers.


Move those parts out of your way, then use the screwdriver to loosen the 3 small screws at the base of the headbasket (wire mesh).


Then remove the 3 screws completely.


Move the screws out of the way, then gently lift the headbasket.


Lift it completely off, leaving the microphone assembly sitting inside of the base.


The inside basket is sort of rectangular, covered with fine white nylon mesh. It should simply pull out by hand - wiggle it a bit, watch out for sharp edges.




Discard the rectangular basket and nylon mesh. Then gently lift the motor up out of the base, with the circuit board FACING you. This is the side to work on FIRST.


Use the pliers to loosen the tiny nuts. These have been painted over at the factory to keep them from coming loose, so use the pliers to completely remove them. This is where you have to begin being very careful not to drop any tiny parts! Also, remember to handle the ribbon motor gingerly.


Also remove the tiny little washers...use your fingernail to lift them off the posts. Don't drop them, if you can help it! Generally, if you drop a part, it ends up being trapped in the base (cup), but it could fall through to the ribbon and ruin the mic - CAREFUL!


Move the loose washers and nuts out of the work area. Now ease the motor out of the frame. Gently push the top and bottom bolts out of the black rubber grommets at the top and bottom of the frame. It is a snug fit, just don't force anything or be in a hurry.




Once the assembly is free of the frame, use the pliers to loosen the long cylindrical nuts on both bolts.


Then carefully finish unscrewing them by hand. Also remove the tiny washers.


Now VERY CAREFULLY remove the waffle plate. The layer of nylon should come along with it. Once this is done, the delicate ribbon element will be exposed. No sneezing or coughing or open windows allowed.


The ribbon element:


Now carefully replace the tiny washers and cylindrical nuts. Tighten them to "very snug" (that's tight enough to stay in place well, but not so tight as to strip out the threads) with the pliers. Don't drop anything on the ribbon. Don't slip with the pliers.


Push the bolts back through the rubber grommets in the frame.


Get the 2 tiny washers and hex nuts, and replace them on the bolts, washers go on first. You might need the pliers once you start them by hand, because the leftover paint makes these a snug fit. Tighten to "very snug".


The first side is done. Now turn it over/around to work on the opposite side. Be sure to CUP your hand - don't let the assembly lay flat in your hand, as you need to protect the ribbon from any contact or air movement.


Use the pliers to remove the 2 hex nuts and lift off the 2 tiny washers, the same as the first side.


Carefully lift off the waffle plate and nylon mesh.


Replace the washers on the bolts, and then the hex nuts. Use the pliers to tighten them down "very snug".


The completely unobstructed ribbon motor:



Next, sqoosh some foam into the gaps between the motor and the frame at the top and bottom. This should help reduce some mechanical resonances, as the motor virtually pivots on the bolts without this additional support.






Now lift up the mic assembly away from the base, and push in the slotted piece of foam, placing the heavy cable in the slot in the foam.


Carefully replace the assembly into the base, taking care not to detach any wires along the way.


Push/pull with the needle-nose pliers if needed, to help everything sit together nicely. The foam filling the base should reduce or eliminate the resonant frequencies that can build up there. Go ahead and speak with an empty coffee cup next to your mouth to get an idea of the types of "telephone" sounds that can be produced in the base...


Replace the outer mesh headbasket and install the first double hex bolt loosely. There are 1/2" squarish inside plates on either side which should have stayed attached to the frame (that the double hex bolt screws into) - IF you had one fall out during the disassembly, THAT side is the side you should start with: a little tricky, but do-able.


Repeat for the opposite side:


Then tighten both double hex bolts to "very snug" with the pliers.


Then replace the three small screws - just get them started by hand...


Then gently tighten with the screwdriver.


Then replace the yoke on top of the bolts.


Finally add the washers and the round knurled nuts, and tighten to finger tight.


Remember that now you almost ALWAYS have to use a pop filter to protect the ribbon element!


And you must promise to COVER the microphone before moving it to a new spot (yes, evidently even moving the microphone from HERE to THERE creates enough air movement to damage the ribbon)!


Remember that we agreed to be MORE CAREFUL with the microphones after they were modified...

Now go and ENJOY your more open-sounding, slightly brighter, less resonant ribbon microphones...go find a brass band, and record them like crazy!

7 comments:

Anonymous said...

Wow, I just came across this page and I must say THANKS! as I plan on eventually purchasing a lower priced ribbon. (Actually I currently use a TLM103 but want to get my feet wet with ribbons since I'm a trumpet player and record a lot of home projects.)

I've heard about ribbon mods before, but seeing them like this, the way you've illustrated what to do, really helps! Thank you!

David Miller

ilamfan said...

Glad to be of some help, David! Pick yourself up a ribbon mic soon, if you can - prices are GREAT in this poor economic climate, and if you're recording trumpet, you NEED the nice mellower/smoother classic character of a ribbon...plus, since the trumpet is such a loud instrument, you can get away without having a pricey mic preamp (which costs more than a cheap ribbon mic does!)...and the preamp is generally a necessity if using the ribbon for vocals or other quiet sources.

THANKS for the comment!

Matt said...

Any reason why you didn't replace the transformer in the ribbon mic for a better quality one?

ilamfan said...

Only because I'm rather hamfisted with a soldering iron, and another $75 per transformer times two mics would be $150. And I'd rather put that $150 toward a new mic, than get a little bit more out of these ribbons. For those who would like to try it, there is a really nice tutorial here:

http://recordinghacks.com/2009/12/31/diy-ribbon-transformer-upgrade/

More signal at the source (via a better transformer) would be best, but I've been more than happy with these mics run through my Rane VP-12's. They give me up to 60dB of very clean gain each, and I never have to push them all the way up, even on the quietest sources.

If someone didn't already have a quality mic pre, however, the transformer replacement would be the way to go.

Anonymous said...

I really don't recommend taking out the perf'd plates on the front and the back of the ribbon.

Just askin to be blown up.

The basket with nylon over it can go tho =)

Robert said...

Thanks for the directions! Very easy to follow. I just modded my Apex 210 and it really does sound way better. I was surprised that this mod also improves the lower frequencies.

Anonymous said...

Hi there,

I did this modification years ago when i first got my pair of t-bone RB500's.

Whilst there is a slight improvement in lows and mids, there is also a drastic drop in high frequency content due to removing the resonant plates. These plates are based on an old ribbon design i think and are essential for a balanced sound. They certainly maintain highs more so than those lost from using the internal pop filter. Without it you have to pile on 8-12 khz eq on high frequency sources and that is not good practice as it introduces more noise ( analogue ) or harshness ( digital ). This is particularly a problem when recording high frequency material like cymbals but obviously less of a problem if source needs some attenuation of the highs ( even beneficial ).

The lack of any internal pop protection from the mod makes the mic's far too easy to damage in normal use - you can never fully prevent accidental knocks to mic's.

In my experience, because of the marked drop in highs and the impractical lack of protection from damage i would personally advise against anyone doing this modification.

All the best anyway as i can see you are trying to be really helpful with this and to each his own anyway.

Cheers