hydrophones and contact microphones - hand made in yorkshire by JrF

frequently asked questions

Q: how long will it take for my order to be dispatched ?

A: I try to dispatch orders as soon as possible and try to keep standard length cabled units made up and ready to send. However, at times of high demand or when ordering custom length cabled units, or indeed when i'm mid-way through making a fresh batch of units, do please allow some time between ordering and dispatch. I'm an artist, lecturer, workshop leader and indeed a father ! so there are time when i'm away or creating work. Please read the 'important' section on the main page for updates on dispatch schedules.

Q: is there another way to pay other than paypal ?

A: yes, you can send a cheque if you are in the UK - made payable to Mr. J. French. Bank transfer is also possible but remember that payment must be in UK sterling and any transfer and currency conversion fees must be factored in.

Q: do you use your microphones yourself ?

A: yes. I’ve been involved in the creative exploration of sound for over 30 years and I use contact microphones and hydrophones extensively in my work. When I began making these units I supplied them only to fellow artists / recordists, however a few years ago I started a blog on various aspects of field recording and tested lots of other contact

microphones and hydrophones. I was surprised at the often poor quality of lower priced units and at how much better the ones I made were, and indeed how well they compared to the more expensive models. As more and more people became interested in field recording I heard lots of stories of people not bothering with contact microphones and hydrophones after having trouble with other models on the market. So, I decided to begin selling mine to the public. They are now used by artists, field recordists, musicians, aquariums, universities, schools, wetland trusts, film and tv crews, swimming pool

technicians all over the world.

Q: whats the difference between the ‘standard’ and the ‘c-series’ contact microphones ?

A: the main differences are:

. the hand produced element on the c-series is larger, giving a wider frequency response and better definition to the middle and bottom end sounds captured.

. the cable on the c-series is higher spec, with lower handling noise and a more efficient signal transfer to the jack.

. in addition, the c-series are constructed to offer increased durability and sturdiness.

. extra coatings of the unique ‘acoustic transfer’ coating have been applied, which further improve the performance of the microphone.

(extra cable is available on request at a charge of £2 per metre for c-series units and £1.50 for standard units)

Q: whats the difference between the ‘standard‘ and the ‘d-series‘ hydrophones ?

A: the main differences are:

. the hand produced element on the d-series is different and has been specially designed to give a wider frequency response and better definition to the middle and bottom end of sounds captured.

. the cable on the d-series is pro-quality, with lower handling noise and a more efficient signal transfer to the jack.

. the injection-moulded capsule design has been chosen to provide an additional character to the audible range and to assist in the weighting of the unit, which has been designed to suspend itself below the surface in reasonable currents (additional weight can be added by attaching fishing line weights to the cable for example)

. extra coatings of the unique ‘acoustic transfer’ coating have been applied, increasing the performance of the microphone.

(extra cable is available on request at a charge of £2 per metre for c & d-series units and £1.50 for standard units)

Q: what is the foam / soft circular dot for on the c-series contact microphones ?

A: this is simply to provide some additional protection to the element when pressing the microphone onto the surface to be recorded. Don't remove it !

NB: the main surface of the contact mic element is on the other side to the dot - it's the 'non-dot' side that should be on the surface to be recorded.

Q: what’s the best way to attach the contact microphones ?

A: I myself use electrical tape. Blu-tak applied directly to the microphone is not ideal as it will leave a residue on the outer coating of the microphone. If you do intend to use it (or other similar putty-style products) wrap some electrical tape around the microphone first.

Q: my recorder has XLR inputs. Why don’t you supply your products with XLR jacks ?

A: as someone who has used and developed this technology over many years I have tried all possible methods to mount this technology directly to XLR jacks without compromising the sound quality or signal stability. In designing reasonably priced units that offer very high quality results the technology used in the elements cannot be mounted to XLR without one of the pins on the jack being hot-wired for example and to do this often leads to background noise and signal instability. It is also important to match the impedance with the recorder. Therefore, the best results are to use standard 3.5mm or 1/4 inch jacks + an impedance matching adaptor if going to XLR inputs. I myself use a Sound Devices recorder with XLR inputs and use an adaptor to convert the 1/4inch jack units to XLR. The difference in sound quality by using this method is that the mid & low range frequency response has a bit more warmth and definition. I now stock a range of pro-built impedance transforming adaptors and other adaptor cables. Click on the accessories tab on the home page for more info.

Q: are you products compatible with the recorder I use ? and will I need a separate pre-amp ?

A: I've yet to find a recorder they aren't compatible with and for example lots of folks use my products with recorders such as:

Sound Devices 702, 722, 744, 788, 442, 633, 644 etc

Olympus LS100, LS10, LS11, LS12 etc

Fostex FR2le

Zoom H2, H4, H4D, H2N, H4N, H5N, H6N

Tascam DR100, DR40, DR680, DR40-wl, 22wl, 44wl, DR60mkII, DR70mkII

Sony PCM-D50

Marantz PMD661

Edirol R-44

Korg MR2

Nagra recorders

and lots more inc. minidisc recorders

You don't need an additional pre-amp in order to get good results and in fact all of the samples on the soundcloud player at the top of this page were recorded directly into the recorders used without any additional mixers, pre-amps or post production.

Q: what sounds will I hear with a coil pick up ?

A: with these simply devices it’s possible to hear the internal electronic signals of all kinds of everyday items such as radios, tv’s, light switches, computers, mobile phones etc.

Q: it says that you have adapted the coil pick ups - what does this mean ?

A: basically, this technology has limiters applied in order to prevent them being used for certain surveillance practices. I buy them from the factory and remove the limiters that inhibit certain signals. This means that they are able to capture a wider and more fascinating range of signals.

Q: what is the special ‘acoustic transfer coating’ that you use ?

A: this unique coating basically helps spread any sound captured across the entire surface of the unit, therefore enhancing the performance of the microphones. It's basically a coating similar to one used in sonar technology to assist in the spread of sound impulses. In addition to the other methods I use, this is one of the reasons my microphones offer such amazing results.

Q: why are your contact microphones and hydrophones cheaper than others on the market ?

A: my microphones can compete, in terms of results, with units costing £100’s of pounds but are priced reasonably because, as a passionate listener and field recordist, I believe people should have access to reasonably priced equipment which will also give them results that encourage them to explore further. 

Q: are the elements you use made specially ?

A: yes, they are made to certain specifications that offer better results than ‘off the shelf’ elements.

Q: if there’s a problem with any unit I buy from you what can I do ?

A: I always do my best to sort out any issue, no matter how long you’ve owned the item. If the problem is down to damage to the unit I will do my best to repair it for you at cost. If its because of a fault then it will be repaired or replaced free of charge of course.

Q: what about ethical sourcing of parts ?
A: I spend quite a bit of time researching where the various components I use come from and its fair to say that this is often difficult. I use hand built elements not produced in China and all elements of them are sourced from Europe from manufacturers with high reputations for their standards of production and work conditions etc.  The cable I use is produced to a specific design in Europe by a cable manufacturer that usually only supplies audio cable to the installation industry. In short, when buying JrF mics you can be sure that the parts have been sourced in Europe and are not the same as cheaper low quality products.

copyright of all material on this website and in the design aspects of JrF products is in place, as is design registration. Any infringement will be acted up and is simply not cricket !