Today I built a pickup using piezo film. I purchased the film in two lengths from Edmund Scientific. I'm reluctant to recommend them as a source because, even the though their prices were low and the delivery was prompt, their website was not entirely honest about shipping costs or availability of items.
Of the two sizes of film they sent me, I used the larger which is 16mm X 73mm (almost 3 inches long). I thought this would fit nicely behind or in front of a bridge. Also, in his fantastic book on pickups, Getting a Bigger Sound, Bart Hopkin writes that the larger films give a stronger signal and a more representative sample of the sound board's movement. I may use the smaller films for a ukulele pickup.
To build this pickup, I followed the guidance from David Fittell's site. I followed most of his instructions, including using shielded cable and a female phone jack. I did not glue cork to the pickup or put heat shrink on the jack.
Using the new film pickup and later the chip pickup I'd already built, I recorded the theme from The Munsters, played on an Epiphone with very old strings. I recorded directly into my recording interface, a Presonus Firebox. This time I taped the pickups behind the bridge using painters' masking tape. The difference between the new film pickup and the disc pickup is significant. The disc gives a much stronger signal. But, the film pickup seems to have a more realistic frequency response.
You'll hear some hiss in the sample with the film pickup. I'm not sure if it's a hum resulting from not yet effectively contacting the ground of the jack to the foil or if it's because of a gain problem. The signal from the film pickup was so low I had the preamp on the Firebox turned up all the way.
The Munsters' Theme - piezo film pickup
The Munsters' Theme - piezo disc pickup
4 comments:
The film has a MUCH better frequency response, and sounds very good; the chip is too mid-honky for me.
Another excellent test.
-Grahame
Thanks. I prefer the film pickup on this guitar too (even though I've always considered myself to be a mid-honky).
Any theories about the hiss? Do you think it is because I had the preamp cranked all the way up or could it be because of the weird way the balanced cable is wired?
couldn't say about the wiring, but maxing out the preamp is recipe for plenty of hiss - that's where I'd look first.
How about recording a test at a lower level and raising the gain using the software; then see if there is similar hiss present.
If the hiss is pre-preamp it should be there in the boosted recording; if it's the preamp itself adding the hiss the boosted recording should sound cleaner, or at least differently hissed.
- Grahame
Thanks Grahame. I'm going to try that this weekend.
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