Here are the photos of two older Cascade LDC microphones. I can’t find any information on them but will update this post as I acquire information.
I’ve had this Electro-Voice mike in my collection for a number of years, but never bothered to test it since it had an Amphenol MC-3 connector on it and I didn’t have the proper cable. But, I acquired a box of Amphenol connectors recently, so I thought it was time to check out this classic mike.
This is a large microphone, comparable in size to my Shure 556 “fat-boy, Elvis” microphone. It weighs in at about 2 ½ pounds. The best I can tell, it first appeared on the market in the late 1940s.
According to the EV spec sheet:
The CARDYNE microphones are cardioid unidirectional dynamic types operating on the E-V Mechanophase principle. They utilize dual phase shifting diaphragms to produce a high degree of uni-directivity at all frequencies.
The CARDYNE models are designed for extremely accurate reproduction of music and speech. The directivity gives it unusual versatility in increasing the working distance from the user by reducing reverberation and acoustic feedback. High output provides an excellent signal-to-noise ratio for broadcasting studio pick-up.
My unit is in excellent physical condition externally, but I decided to open up the mike to make sure the insides were OK before wiring up the new cable. Two screws on the back loosened the rear of the case and two screws under that loosened the front cover.
The insides were clean and not corroded, but all of the rubber shock-mount material had hardened and some of it turned to powder. Since the cartridge assembly just flopping around inside the case, I needed to replace all of the shock-mount material.
This microphone achieves its cardioid directionality by means of a resonance chamber that is part of the dynamic cartridge assembly. This assembly rests against a block of sponge rubber that is about ½ in. thick, 1 inch high, and two inches long. I was easily able to cut a replacement piece from a piece of ½ rubber that I had and glued it into place. There were a couple of bumpers on the front of the cartridge assembly that rested against the front of the case. These I replaced with pieces of self-adhesive rubber that I cut from a sheet that I bought from a craft store.
The shock mounts that held the back of the resonator to the mike frame were not as simple. What I needed were eight ½ inch diameter rubber washers, ¼ inch thick, with a ¼ inch hole in the center. I used a hole punch to punch the ½ circles out of a sheet of rubber, and then punched a ¼ inch hole in each one of those. These were close enough in size that I was able to re-assemble the shock mounts with the new rubber pieces, tighten the screws, and verify that is worked properly.
I double-checked the wiring inside of the mike to make sure that I hadn’t broken any wires, and then put the mike back together. I didn’t have any silk or thin foam to replace the windscreen inside the shell, but it was in fairly good shape, so I’ll save that for a later date. I then used my Dremel tool with a brass brush to remove oxidation from the exterior of the mike, and it cleaned up nicely.
I wired up a new cable for the mike to go from the Amphenol connector on the mike to a standard male XLR connector. I set the impedance switch on the back of the mike to “Low” and plugged the mike in. It worked.
Then, into the studio for some comparative recordings between this E-V mike and the Shure 556. The E-V is brighter and has a higher output than the Shure. Both mikes seem to have a significant amount of distortion. I am guessing that the capsules in both mikes are showing their age and may have some damage. Replacement capsules of the same type are not available. I could upgrade to a newer capsule, but then they would no longer be vintage mikes.
So, I’ll just be on the lookout for NOS capsules on eBay. There was a NOS capsule for a Shure 55S on eBay this week, but the mounting is entirely different that the 556, so I passed on it even though it is probably the same capsule. These mikes will be mostly for decoration, except for that occasional funky recording project that pops up now and then.
What is interesting is the amount of mechanical apparatus that was needed back in the 40s to create a directional mike. My new Electro-Voice N/D 468 microphones provide hyper-cardioid directionality and great sound in a package that has probably 1/8 the volume of the old 726. We’ve come a long way in the past 70 years!
Microphone kits are readily available these days, at least for condenser and ribbon microphones, but that certainly wasn’t the case in the early 1960s. I was what today we would call a geek in my younger years, so when I saw the ad for the American Basic Science Club kits in the back of an electronics magazine, I talked my parents into subscribing me to the set of 8 monthly kits for my tenth birthday.
James S. Kerr created the American Basic Science Club in 1957 and operated the company into the early 1980s. The kits were elegantly designed so that you could reuse many of the items for different experiments and it certainly was a wonderful introduction to science and technology with a lot of emphasis on learning the basic principles of electronics, optics, and many other areas. The ad below shows all of the different experiments that one could do and the kits evolved and expanded over their lifetime with the addition of an analog computer later on.
These kits contained a lot of electronics projects with vacuum tube circuitry. Mine used three octal tubes, but later kits used miniature tubes. The company never made the transition to solid state circuitry.
One of the projects was an AM radio transmitter, and that project required a microphone, so included in the kit were parts to build a carbon microphone from scratch. I built it, it worked, and so began my saga with microphones and audio. I don’t have any of the pieces of the original kits except maybe for the tuning capacitor.
A few years ago, the nostalgia bug bit and I started buying some of the American Basic Science Club kits on eBay as they showed up for sale, fortunately before the prices shot up. I managed to acquire most of the whole set at that time. I keep some of the pieces on display, but most of the kits are still in their original boxes.
I thought it might be fun to construct that microphone again, so I started rummaging through the boxes and managed to find all the pieces to assemble the same mike that I had built 55 years earlier. The instructions were very basic, and it was certainly a little bit of a challenge. I wondered how I was able to accomplish it when I was only ten years old, but I probably had a bit of help from my dad who could build just about anything.
A carbon microphone works as a variable resistor. Carbon grains are loosely held in a small chamber between two metal contacts. One of the contacts is attached to the diaphragm of the microphone, and the vibrations of the diaphragm from sound move the carbon granules and vary the resistance at the vibrational rate. A small DC bias current is passed through the microphone, and thus a varying voltage is generated. If you hook a carbon microphone, a headphone and a battery in series, you’ve built a simple telephone.
The body of this microphone was stamped out of masonite. The hole in the handle was the chamber that held the carbon particles. A tinfoil layer covered the bottom of the hole and contacted the carbon granules. A screw head attached to the diaphragm made contact with the other end of the granules.
There were few instructions, and I needed to rely on the drawing for most of the assembly. The screw head from the diaphragm passed through a little square of plastic bag that was glued across the top of that cavity to keep the carbon granules from leaking out. The type of glue wasn’t specified, and I kept choosing the wrong kind and softening the piece of plastic bag and having the carbon grains leak out. I finally used a piece of double-stick tape to attach the plastic bag, and ended up with a non-leaking microphone.
I applied a 9V bias to the microphone through a resistor and coupled the signal from the microphone to the line input of an amplifier through a capacitor.
And just like the first one, I had a working microphone. Not exactly hi-fi, not even telephone quality, but able to reproduce understandable speech. I still find it amazing that you can build a working microphone with the simplest of parts and basic hand tools.
I was aware of the possibility that I would occasionally have a problem with recording due to external noise that was beyond my control. It could be a lawnmower, chainsaw or any of a variety of outdoor tools and appliances, and it could happen at any time. I hadn’t had an opportunity to gauge the amount of threat that existed. Until last week.
There were several large maples and a pear tree that were shading my garden so much that I soon wouldn’t have enough sunlight to grow vegetables, so I contracted to have the trees removed. The crew worked quickly and efficiently and once enough of the trees were down, it was time to grind up the branches.
They parked the large chipper in my driveway, which put it 15-20 feet from my basement control room. If you have never been near an operating wood chipper, they are one of the loudest mechanical devices you will ever encounter. This machine would be the ultimate test of sound isolation for my new studio.
Once the engine was going and they were grinding branches and limbs on a continuous basis, I headed for the basement. I sat in the control room with the chipper less than 20 feet away, and although audible, it would not have been disruptive to a recording or mixing session.
I went out to the studio and listened. If I listened really hard, it was just barely audible. I can’t think of any close-miking situation where the sound would have gotten into the recording. That was excellent news! I was convinced that no matter what is going on outside, recording or mixing wouldn’t be disturbed. After this, if any outdoor sounds disrupt a recording session, I know that I probably have a lot bigger problems than an interrupted session.
It’s time to finish up a few leftover tasks in the room and upgrade the equipment and software to the latest.
The computer we were running for audio was an old Windows XP machine, and I was running ProTools 7.5. I wanted to upgrade to Windows 10, and the ProTools 11. This old machine just wouldn’t cut it anymore, so I built a new machine that was almost identical to my video editing machine. It has an Intel i7 Haswell 6-core processor, 16 Gigabytes of RAM and an SSD drive for the C drive. The computer is built into an NZXT cabinet, which is acoustically insulated and about as quiet as possible. I installed four, 4-Terabyte hard drives for storage and backup.
I installed Windows 8, and then 10 when it became available shortly after that, and subscribed to ProTools so that we always have the latest version. The upgrade went smoothly, ProTools integrated easily with the Digi 003 and rarely crashes anymore.
I spend a lot of time listening to different material, both my own recordings and commercial recordings that have a reputation for being well-recorded. The JBL speakers have adjustments for the midrange speaker and the tweeter, over the past few weeks I have adjusted those for the most balanced sound. I was still noticing an occasional brittleness in some of the sound and wound up replacing the tweeter in one of the speakers. I had replaced the one in the other speaker a few years back. I think I am now satisfied that the speakers and everything in the sound chain are working correctly. We’ll discuss this listening process in detail in a future post.
I built a set of shelves under the diffuser at the back of the room to hold microphones and other odds and ends. Our old microphone collection is displayed on the top of it.
There was a final bit of decorating to do; I added the Norwest sign to the back diffuser, added some dark red accent strips to all of the diffusers, matching the color of the ATS panels. I also built a cable cover that covered the wires coming to the rack between the two ATS absorption panels. I added a couple of VU meters, mostly for looks, to the panel to the left of the Digi 003 and build an oak frame to hold the Mackie BigKnob. There was probably a bunch of other trim items and painting done at this point.
Finally, without a window, the front wall looked a bit empty, so I designed a Norwest Studios sign for the front wall and had it printed by Office Max and then glued to foam core. I was worried that it might affect the sound, but it didn’t since the foam core is quite dead and absorptive.
I am extremely pleased with the sound of the room. The stereo imaging and sound are good no matter where you sit. This room is considerably better that the control room at my old studio. It’s also a lot more comfortable.
A home studio is probably not a good fit if you are working with whoever comes in off the street. But, if you are doing your own recordings, or working with a select list of clients that you have known for a while, this is a very comfortable situation both for you and the people you are recording. Also, a relaxed, comfortable environment encourages a good performance and creativity and produces a better end product.
It’s been a long road, and the project took longer than I had planned, but it has certainly been worth the effort. I am ecstatic with the results that we achieved and don’t miss my old space in the least bit.
Before and After Pictures
Back Wall and Closet
The first and possibly the most difficult task was to empty out the storage room that had been accumulating junk for over 35 years. A good portion went into the trash, I donated some items, and the items that I decided to keep went into the garage or other parts of the basement. Finding a permanent place for things such as the Christmas Tree and decorations was going to be a real challenge. Then we disassembled the shelves and saved some of the wood for use in reconstruction.
My son Jeff had already run CAT5E cables for network and phone that connected to a new switch at the other end of the basement. I had new high-speed Internet service installed earlier, and the network was up and running, and the new phone service was working. That cable installation was actually the first step of this project.
After about a week of hard work, the room was finally cleared out. After a good cleaning, the first task was to repair some cracks and apply waterproof paint to the walls. This room sometimes gets a bit of seepage during unusually heavy rainstorms, so I wanted to take care of that before anything else. I chiseled out the cracks and re-mortared them and then applied to coats of waterproofing paint to the walls.
The next item on the agenda was the electrical work. There was only one outlet in the room and a single bare bulb, which was hardly adequate. The existing wiring was in conduit as required by code in Cook County, Illinois, so adding circuits and doing modifications is easier than with Romex. I added two more ceiling boxes for additional track lighting along with a dimmer for each box so that I could control the brightness as needed. I added a total of six outlets, with one inside the front wall in case we want to add a video monitor in front of the console at some point in the future. I also added a kill switch that would turn all of the outlets off except the one going to the computer.
The next task was framing the front wall which would hold the JBL speakers. The space behind this wall was to be filled with fiberglass and then covered with burlap to absorb sound and make the front of the room dead. We left the concrete block sidewalls alone and would add the necessary sound treatment later. Then we built frames for the doors in front of the alcove at the back of the room that would be a storage closet.
We found a nice solid door with lots of windows and built a new frame and installed it to replace the original hollow core door. Installation of the door turned out to be a two-day job as the concrete block walls were not plumb and getting the door to fit properly was a problem. But it was worth the effort, as the door adds aesthetically to the look of the space and allows a limited view of the recording area.
The desk and the half wall surrounding it were next. We had removed that wall in sections from the old studio, and the sections were fortunately screwed together instead of nailed. The part of the desk that sits to the engineer’s right was too wide for this room, so we ripped about 8 inches off of it.
We also made the proper modification to the half-wall that surrounds the desk. We then screwed the half-wall together and fixed it to the concrete floor with Tapcon screws. I then installed the two outlets for the equipment in the half-wall.
Since this room had gotten some seepage in the past, I wanted a waterproof floor, so I installed a vinyl simulated oak plank floor in the whole room. The floor isn’t glued down, but the planks lock together, and the floor can expand and contract with the changes in temperature. Since the planks are removable, it will be possible to replace any that get damaged. With this flooring down, the look of the room was transformed, and I began to believe we were creating a unique and comfortable space.
Now that we had installed the flooring, we put the desks back in place and attached them to the half-wall. We replaced the insulation in the back side of the half-wall, and I stapled a new layer of burlap over the studs, leaving the back of the wall acoustically absorbent. Since most of this wall faces the speakers, the fiberglass prevents any bounce-back of the sound into the room.
This completed the structural work on the room. The closet doors still need to be installed and appropriate sound treatment to the walls, but now we can install some equipment and start working on th sound of the room.
Early this year, I decided to close up the recording studio and video production facility that I had been operating for 40 years and downsize to a home studio. The building I had been renting was occasionally up for sale, and even if I could stay, it needed a major facelift.
The recording and video business had changed radically over the years with the availability of high-quality, low-cost equipment and the proliferation of home studios. Anyone with an iPhone thought they were a video producer. I was tired of the rat race and wanted to produce some educational products to share my knowledge of the industry with the multitudes of people now doing their own recording. This blog is the first move in that direction.
My video editing suite and office have been moved into a spare bedroom at home and are operational, so what remains now is the tougher task of building a new audio mixing and mastering room in the basement at home and adapting my rec room to function as a recording space.
The next bunch of blog posts will talk about building a home studio as I go through the process including the thought process, compromises that needed to be made and some details of the construction process. After that, we intend on producing a series of blog articles and videos on choosing and using microphones and recording techniques specifically aimed at home studio and small commercial studio owners.
But right now we are finishing up our last session at the old studio mastering an album for Even the Jackals. This is a great album and I am happy to be part of it. We’ll finish our last session tonight and tomorrow we’ll start removing the equipment and storing it in my garage for a month or two until the new room is done. Sony Sound Forge and CD Architect are installed in my new video editing room, so I can make a few more tweaks to the album if necessary.
Here we are, a few days later and all of the recording equipment has been removed and safely stored in my garage. I haven’t seen the studio empty in 20 years and it is a strange view.
So here’s a quick photo for posterity and then on to designing and building a new mastering and recording space and writing about the process for the next generation of recording engineers and producers.
In the next blog post, we’ll talk about the design of the new spaces and the compromises we had to make.
After that will be a series of articles detailing our construction and outfitting process and an evaluation of the results.