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5

I use Cold Gold, a few other hand-made ones, and the rubber contact-mic adapter for the Aquarian Audio H2a hydrophone. The C-Ducers sound pretty compelling - high noise floors are common with cheap piezos - but the H2a is a stellar contact mic...provided you can attach its heavy bulk to something effectively. Tim Prebble and others also like the Barcus Berry ...


4

Ruben, You mention that you don't wan't to incorporate phase at all—I'm guessing that you mean you don't want to design a kind of phase shift based on delay? Keep in mind that, unless your two mics are placed in the exact same point in space, there will be some difference in time arrival (aka, a phase difference) between the two signals. This is a very good ...


4

The simple answer is no - there are some misunderstandings that I need to clear up for you: The audio and video frequencies you have coupled in an old fashioned TV signal are so far apart that there is no overlap. (Audio 20Hz to 20kHz, and video is up around 4MHz) When the signal goes to the TV, the audio frequencies are decoupled, then the horizontal and ...


4

Consider using an anechoic chamber from others. Every microphone and speaker manufacturer will have one, most Universities have huge EMI measurement chambers (working perfectly). They might let you use it for an hour at a time, or you can rent it for a day for some more money. If you need to build one by your self, start with a noise floor measurement box. ...


3

contact mics are pretty cheap. I own some cold gold ones as well, but I never use them anymore. Now I roll with my Jez Riley French C series ones. here's some classic laser stuff I did with them: [soundcloud]rcoronado/guy-wire-contact-mics-huge[/soundcloud] I run them through (inexpensive) hosa MIT-129 impedance transformers to get them matched up ...


3

I think it depends on what mics you plan on using. Schoeps MK and Neumann KK pairs will work. A Sennheiser MKH40/30 rig won't fit in a mono Rycote all that well. While it is not ideal, it is possible to fit an MS pair inside a mono Rycote. Especially if you can find the older, non-lyre based blimps. You just need smaller bands. I have a rig very similar to ...


3

Here is a nifty preamp circuit that provides a FET buffer and balances the signal, which deals with all the issues you are discussing. The circuit is based on the work of Alex Rice.) You attach the piezo to the circuit with a length of shielded mic cable, then run a mic cable from the circuit to a male XLR. This plugs into your recorder which supplies ...


3

Quite an interesting project indeed. The paper towel roll and cups are are working as an acoustic megaphone, also called (in ancient times) speaking trumpet. Directional focus of the radiating sound waves is part of the way the megaphone works, but that's not all, as, as you have noticed, there is also amplification in other directions, not just the front ...


3

There are a number of factors involved here but mainly frequency response, transient response, signal to noise ratio (S/N) and total harmonic distortion (THD). Frequency response is largely dependent on the size, shape and mass of a speaker cone and there is no such thing as a speaker with perfect frequency response. But most significantly, the size of a ...


2

Control over high mids and high frequencies is easy but it will be the lows that will do your head in, and I do believe that's where the commercial solutions start to make a difference. get your foam pre-cut and pre-painted to spare yourself time and trouble, but also it won't look messy. If you plan to do any "professional" work for clients coming to ...


2

If possible, build it on the ground floor with as a direct coupling to solid earth. Pretty much all man made structures will have resonance in the floors. Concrete structural buildings carries transients surprisingly well (in a bad way). It stuff like this that you won't really think about until you start recording low level sounds like foley. A decent pit ...


2

The key to good foley pits is isolation and quality of sound. Good foley pits are expensive to make but the investment is worth it. The kind of wood you use to box the pit is crucial to the acoustics of the pit as well as durability. Hardwood like oak, teak, seringa are good. Your comment about using rubber insulation is spot on. But you can use the rubber ...


2

They can definitely be tricky to get usable material out of but with some experimentation can yield some amazing source. I have a bunch of various contact mics from these guys: Cold Gold http://contactmicrophones.com/ They make an interesting and affordable selection of various transducers. They also sell some of the bare parts for making your own ...


2

The key to a good contact mic lies more in the preamp than in the transducer itself. Contact mics will inherently pick up sound from a very unique perspective, but you need preamp circuitry that will not only keep noise low but will also provide the necessary impedance to match the high load of the mic itself. Because impedance is a frequency-dependent ...


2

There are pre-existing facilities that regularly measure the frequency response of microphones. you should call one of them (try pcb) and talk to them about your project... A chamber might not be the best way to measure this. But if you do want to build a chamber, a lot depends on what the lowest frequency you want to measure. If you have a quiet space, ...


2

In response to Colin, I too am curious about the stereo Trance Audio rig, so I wrote them. They responded with the following specs: The stereo Inducer is a custom-built specially designed low-noise high-definition stereo system that's aimed towards sound designers. The Inducer runs 2 Acoustic Lens transducers, the heart of the system. The Lenses, which ...


2

Though I don't own any, Barcus Berry contact mics sound awesome. I use the Aquarian Audio H2a contact mic adapter. I also bought a contact mic a couple of years back from these guys. Don't think they sell their mics anymore, but there is a useful guide on how to build your own. I'm also looking forward to hearing more about the new Trance Audio stereo set ...


2

It's actually a complicated thing, how much space to put behind a driver. The air mass behind the driver actually affects how the driver moves. If you put the right volume of air behind the driver, you can even out the low end. If you put the right volume of air and the right size port, you can change the frequency response of the system (with a few ...


2

Traditionally, it was called "grille-cloth" and it was made from a coarse-weave of rather thick plastic filaments. It is still available in many places, particularly those vendors who supply people restoring vintage equipment. Modern speakers tend to use more conventional material similar to (or identical as) common, inexpensive polyester double-knit. It ...


2

Schizomorph makes a solid answer for all the technical details, but I'm going to break it down more basically. Sound consists of pressure changes. A speaker makes sound by moving a diaphragm that pushes air to make pressure changes. The volume of a sound is determined by how much air moves and how fast it moves. Small speakers can only move so much air....


1

Unfortunately "small" and "anechoic" are mutually exclusive, at least at low frequencies. The length of the wedge absorbers needs to be at least a quarter of a wave length plus some extra space for the field dissipate. If you need to do less-echoic measurements, your best shot may be to find a large open space, get as far away from reflecting surfaces as ...


1

I'm afraid for that budget you're not going to get it any better than a single stationary mic. Both flute and violin are rather easier to mic and bring out in a PA mix than acoustic guitars, mandolins etc., so if that's the context, you have no drums, electric guitars etc., I'd stay with a single mic. Of course, you need to set it up right! First, you ...


1

Cellotape - I think it would sound very christmas-like if you layer some bell jingling with cellotape being stretched out for gift wrapping :) For the gift shaking I would use a shoe box and fill it with various types of objects for example:- plastic toys, DVD cases, coins etc. Then shake the box with various degrees of excitement! In terms of tree ...


1

I am curious what specific wire did the metalwork artist recommend to you? To join bronze rods to stainless steel I would try one of two different ways: silver soldering via torch or bronze brazing via TIG. I've used regular Silicon Bronze extensively to braze weld steel using TIG, but have read that you need a flux to braze/braze weld to stainless due to ...


1

Well, with the material prices you are quoting + plus the research/development that must have gone into the originals, the cost of a Waterphone is entirely reasonable I'd say. I do lust for one myself (just listen to the Tom Waits song "Shoreleave" to understand why). I guess getting all the individual elements of the instrument together in just one package ...


1

Found this http://blog.makezine.com/2011/12/20/collins-lab-diy-contact-mic/


1

I've succesfully build some mics using electret caps. I began with the panasonic wm61a soldered on a rugular 3,5mm plug cable running on pip. It was ok. I attempted the Alice build, but got stuck as the my circuit wasn't working. I've set it aside a haven't picked it up since. My most recent build is a dummy head for binaural recoding using the Primo em-...


1

I have. I never bothered building any advanced housings. I focused on placement and also tried various stereo mounting techniques all wit pretty good results. It may not stand up to the very best mics, but mine are far from bad. Make sure for fx recording to get good sensitivity and low noise. What's great is that the capsules are inexpensive enough that ...


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