Introduction: Ribbon Microphone Tuner (Tensioner)
Here is my 5th in a series of tools to help the DIY'er when it comes to making ribbon microphones. This combines the ribbon alignment jigs I made for my other instructables (for 3 different ribbon microphone trusses) into what I'm calling my version 1 - Ribbon Tuner/Tensioner. I'm intending to automate Version 2, but for now, this version is manual, using a threaded rod instead of a stepper. I needed this to be able to sort out all of the circuitry required to automate it. However, even in its current state, it certainly can help anyone who is trying to mount a ribbon in a truss, and get reliable and consistent tension on it.
Where to get Ribbon Material and corrugator
Just wanted to mention for those who might ask, just where can I get Ribbon microphone ribbon material? Rick at http://www.diyribbonmic.com/parts/ sells nice .8 micron sheets. Lebow also sells sheets from .65 micron to 12.5 micron, although you really don't want to go thicker than 2.5 micron. (Rick's .8 is nicer than Lebow's .8) I wouldn't recommend anything thinner than .8 micron. You can get a basic ribbon corrugator from Amazon https://www.amazon.com/gp/product/B0054G623Y/ref=o... which works really well. In addition, you can check out my other instructables where I took these gears and stuck them in a 3-D printed frame, along with Arduino control (I'm also planning on updating that project with new gears and a change to the frame). I also provide cutting info and lots of guides in my other instructables with respect to working with the ribbon material.
Working with Ribbon material
While I am trying to create a set of tools to make it much easier to Re-ribbon a ribbon microphone, I still want to point out, it ain't exactly easy. You need to wear a surgical mask, close off your room, turn off the fans, and close off your heater/A/C vents. Ribbon material is very delicate, and is generally tough to work with. If you aren't patient, slow and methodical, and willing to go through a couple of ribbons at a time, this probably isn't for you. However, I think between this and my earlier instructables, and the ones still yet to come, I think these offer you all of the tools you need to be extremely successful at building and repairing your own ribbon microphones.
Tuner Circuit Coming
I will follow up with another instructable, where I have an Adruino, an AD9850, and a 2 line LCD display with some other parts, to use a strobe to tune the ribbon. This Adruino /AD9850 combo, will allow you to pick the resonant frequency you want to tune the ribbon to, feed the sign wave into the ribbon, and then using the strobe, you adjust the knob (ribbon tension), until the ribbon freezes, which would be resonance. Once I get this working, I'll move on to a stepper version.
Once you have the ribbon cut for a microphone, the next biggest pain is to lay the ribbon into the truss, to get it centered, and then once you have fixed one end, to properly put tension on the ribbon. Too loose, and it's flopping around, too tight, the corrugations disappear, and in both cases audio quality suffers.
Instead of trying to just lay the Ribbon Truss on your desk, so it can flop around, what can truly help, is a fixture, to place the Ribbon Truss into, to help you lay the ribbon in place. That's what I was trying to accomplish with my ribbon alignment jigs.
But the next big black art trick is to properly tension the ribbon. You have to clamp one end of the ribbon down (while making sure it is centered), and then pull on the other end, and then by use of your magical non-existent 3rd hand, screw the other clamp down. In using this tensioner, you can clamp the one end down, and then once you have the other end of the ribbon centered, you can place a weight on the ribbon, on the moving end of the tensioner.
You can then slowly adjust the tension with the screw, and once you are satisfied, it will stay in place, leaving both hands free to put the other clamp in place and screw it down. (As I mentioned earlier, electronics help is coming to perfect the tuning)
This version 1, has a threaded rod, with a knob on one end, and the other end fits into a moving slider, which has two return springs helping hold it in place.
One Tuner for Many Ribbon Microphones
As you can see, rather than make the thing for one specific ribbon truss (model of microphone), I've made this to use an interchangeable carrier. This way, I can print different carriers for different ribbon trusses, while still using the same main body. I made it big enough to support a wide variety of Ribbon Trusses, and it seems like the Apex Ribbon microphone has the biggest truss that I've seen, so I sized it up to fit that.
As I come across more Ribbon microphone trusses, and create carriers for them, I will update this post. Right now, I have carriers for Rick's (http://www.diyribbonmic.com/) mic truss, the MXL R80 and MXL R144.
You'll notice, that I left the area directly under the ribbon element itself open, both on the carriers, and main body. While this might let the ribbon sag into the gap when you are initially placing the ribbon, I did so, so when I get around to doing actual electrical resonance tuning on the ribbon to set the tension, the ribbon has free air space beneath it to move.
Both the fixed and moving end carriers are held in place with 4 pins. In my case, I used M3x6mm grub screws, partially screwed in.
The moving end uses 4 linear bearings riding on 8mm rods. There is about 30mm of travel on the moving end.
The threaded rod is from home depot, and is just a standard 1/4" threaded rod with matching nuts, and I made a knob for it.
Well, here goes...
Step 1: Parts List
- 3D Printer files
- I use Simplify3D, and add all supports 2mm 30 degrees, albeit it overkill, and then manually remove some of the supports as described.
- Main Body - bottom down with supports
- Clear out support from all holes where the screws go through
- Moving End Body - print bottom down
- Moving End - Print Upsidedown
- Knob - Print with the hole for the nut facing up
- Rick's www.diyribbonmic.com fixed truss end
- Ribbon moving end fixture.
- Note, I made 2 versions of this, one which lets the aluminum bar stock slide a bit side to side (to potentially realign the ribbon, when you drop it on), and one with no play at all. I'm still sorting out which I like better.
- MXL R80 carrier
- MXL R144 carrier
I printed them with 30% infill, 4 shells, 4 top and bottom layers (cause that's just the way I do things). Again, I know it's way overkill. You can probably do 2 top and bottom with 2 shells and 15% infill, I just wanted it to be sturdier.
- 4 - LM8UU Linear Bearings - To insert into the moving end - I used these - https://www.amazon.com/gp/product/B00OZJMX1Q/ref=o...
- 2 - 8MM rods trimmed to 105mm long - This is what the moving end slides on
- I used these from Amazon - https://www.amazon.com/gp/product/B017SH7WCG/ref=o...
- I used this chop saw from Harbor Freight - http://www.harborfreight.com/6-in-55-amp-cut-off-s...
- These are simply used as pins to hold the carrier in place on the main bodies.
- You will need an addition 4 screws for each carrier you make
- 4 to hold the moving body rods in place
- 4 to hold the linear bearing in place on the moving body
- 5 to hold the 2 main bodies together.
- I just ordered the following from McMaster, to see if they work better than the 3/8' rod stock as the 3/8" seems too easy to fall over. 12mm Hex Stock - 8252T61, and 1/2" Rectangular bar 9008K81
Step 2: Putting It Together
I'm going to keep this pretty brief, as I think in looking at the pictures, this is pretty straightforward.
- You will see that all of these parts are printed in White, however, I suggest that if you intend to use the strobe tuning, which will be described in my next Instructable, that you at least print the Ribbon Carriers in Black.
- Print all of the parts. Do the normal clean up, removing support and make sure all of the screws work freely through the holes, and the nuts fit well in their captive slots. Make sure that the holes for the carrier pins in the main body and the moving body are big enough for the grub screws to easily slide in and out. However, on the carriers themselves, you want the grub screws to fit snugly in the carriers. The carriers should have the grub screws permanently mounted in them. Before you install the linear bearings, make sure you remove the support all the way through for the rod. Once you press in the linear bearings, there's no need to remove them. For all intents and purpose, they really don't need the locking screws, but I use the front 2 screws to hold on to the one end of the return spring.
- Install the linear bearing in the moving body. Install the 4 captive nuts. Use the short grub screws or just regular short screws on the back side of the body to hold the linear bearing in place.
- Install the longer 15mm screws in the front portion of the moving body. These not only hold the linear bearings in place, but also hold one end of the return springs.
- Install the M4 x 20mm screws in the main body as shown. You want the long portion of the screw inside the main body to hold the other end of the return springs. I used washers on both sides, to give them a little extra support, so the plastic doesn't crack.
- Note: In the pictures, you will see where I had to shorten up the length of the springs. I modified the print files to move the screws back, so you should be able to just loop the sping on correctly.
- Connect the main body to the other portion that holds the moving body, using the 3 M3 x 10mmscrews and the 2 M3 x 16mm screws. Don't over tighten.
- Install the captive nuts that are used to hold the 8mm rods in place.
- Holding the moving body in place, install the 8mm x XX rods through the end holes, through the moving body and then into the main body holes. Then using the M3 x 16mm grub screws (or regular screws) to hold the rods in place.
- Now grab 2 springs from the Harbor Freight spring kit, and run through the holes, capture one end of each on the moving body, and the other end on the M4 screw heads inside the main body.
- Take the 1/4" nut, and stick it in the captive nut spot for it in the main body. You really don't need to glue it, but you can. Just don't get any glue on the threads.
- Take a 1/4" nut and glue it into the knob, and screw the threaded rod into this nut. I let some glue get on the threads to help hold the knob onto the rod.
- Screw the threaded rod into the main body, and keep going until it firmly sits in the hole for it on the moving body.
Whee.. you're done with the main build
- For the carriers, make sure that the holes in the main body and moving body are opened up enough for the grub screw to easily slide in and out.
- Then screw the 4 grub screws into each carrier.
- Then nicely trim some Teflon tape to the section where the slot is for the ribbon. This helps the ribbon stick to the metal moving pin, and not to the plastic carrier.
Now for the last part. Some aluminum.
- Cut 2 pieces of 3/8" diameter aluminum rod 20mm in length. You would use these to help align the ribbon and get basic tension on it, before you clamp things down. Smooth the ends.
- As I mentioned I order 1/2" square and 12mm hex from McMaster to see if it works better.
- Cut the 1/8" x 3/4" bar stock into 20mm sections. Smooth off the cut ends, as one side will be up against the ribbon material.Smooth off the cut ends, as one side will be up against the ribbon material. Drill a hole at the other end and attach a thin gauge red wire. This will be your electrical contact for tuning the ribbon in my next Instructable. This piece of metal fits into the slot on the moving body carrier to lock the ribbon in place, while you adjust the tension.
Step 3: OK, Now How Do I Use This Thing?
- First grab the carrier for the ribbon motor you want to re-ribbon and install it in the main body. In this example, I am using Rick's ribbon motor from http://www.diyribbonmic.com/parts/
- In this case, I have soldered a wire to the negative side of the ribbon motor body, so I can electrically tune it.
- Following my other instructables, cut a piece of ribbon foil the proper width for the motor, and then corrugate it (again, you can refer to my other instructable)
- In this example, I am just using some household kitchen foil, to make it easier for me to take pictures and not worry about tearing the ribbon.
- Lay the ribbon into the motor, being careful not to allow the ribbon to fall through the body.
- In this case, I use the aluminum rod sections to help get the ribbon generally aligned.
- Once you are happy with getting the end of the ribbon centered on the main body, go ahead and screw the clip in place to fix that end of the ribbon.
- Now with the one end fixed and set, just get the ribbon centered and just only very light tension on it. You just want enough to see that if you started to apply more tension, it would stay centered.
- Now place the aluminum bar stock into the slot on the moving body. While you are putting the holder in place, make sure the ribbon stays centered. This should lock the ribbon in place, so you can put tension on it.
- Now you can start adjusting the knob to slowly put tension on the ribbon.
- For now, you will need to eyeball the tension. Practice with some thicker ribbon material (like 2.5 micron) so you can see the difference between too loose, and too tight.
- A number of you out there already know how to electrically tune either with resonance voltage checking or a strobe. So you should be good to go.
- For the rest of you, if you want to tune your ribbons, so for example, you can more closely match 2 ribbons in a pair, you will need to wait for my next instructable with that circuitry.
Step 4: What's Next
In my next instructable, as I explained earlier, I will have the Arduino driving an AD9850 signal generator. This will have an encoder to set the resonant frequency you want to set in 1Hz increments. The output will have a sine wave signal to feed the ribbon, and a signal to feed the LED strobe. Feedback I'm getting is telling me that the strobe should be about 3Hz out of sync with the audio signal, so you can actually see some ribbon motion. But I'll sort that once I get in earnest with that project. But I also intend to include a gain control for the signal level going to the ribbon. A 2 line LCD display will display the set frequency and the voltage of the signal.
I'm interested to see how easy it is to do things manually. However, virtually all of the components and much of the code can be reused to drive a stepper, using another voltage reading for the resonance, rather than a strobe. But we'll see.
Have fun, and I look forward to your feedback.
Even without the electrical or strobe tuning, this manual tuning body should be extremely helpful as it is, and should help you get decent tension on your ribbons. I'm looking to add more carriers for additional ribbon mics as I can get them.
Stay tuned for more. (Stay tuned, get it, oh my gosh, I'm so funny)
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