120 Watts with Excellent Specs

Just arrived today from the UK: only $25 for a completely integrated 120 watt amplifier with very good performance characteristics. We had this up and running in short order with as much volume as we dared to push through our test speaker! Perfect for the signal chain feeding the larger speakers in our prototype design.

Synchronous Chorusing of two Peepers

Females have a perceptual bias towards the first call of a sequence. The males have evolved to
make call-timing adjustments to their own free-running call period in response to competitors in their immediate environment. This is a short segment of a recording of the advertisement calls of two males. The frogs were approximately four feet apart; the microphone was held equidistant between the two. In this trace, one frog delays his call until he becomes the leading caller. As this calling bout continued, the other frog subsequently adjusted his timing to become the first caller; this pattern repeates througout the recording. The original audio can be found by clicking on the title of this post. Our next step is a stereo recording with two microphones as the live effect is striking.

More Peeping

iButton Water Temperature Test

The iButton inside the brass chamber was suspended from a tree branch just below the surface of the Peeper swamp for 48 hours starting at 8pm. The following day, it was very warm with the air temperature rising above 90 degrees. Both the night before and night after were much cooler as was the second day. Temperature sample rate was 5 min/sample (horizontal scale is 5 minutes/tick mark). Information about iButtons is available by clicking on the title of this post which links to the Maxim-IC site.

iButton Deep Water Chamber

This is a simple brass chamber containing a temperature recording iButton mounted on a foam-core insert. The orange tape indicates the end most tightly secured; both Teflon tape and heavy rubber gaskets internally are used. Tonight, we suspended it just beneath the water surface in the swampy area behind our house with the device set to take temperature samples every 5 minutes.

Spring Peeper Call

This is a spectral analysis of a recording we made tonight of a spring peeper. The fundamental or dominant frequency is consistently near 3200Hz. The male calls as loudly as possible at this pitch to attract a mate. Distinct harmonics are seen at 2x (6400Hz) and 3x (9600Hz) with overtones spaced evenly between at 1.5, 2.5, etc. Audacity is the audio tool used for presentation and analysis.

Spring Peepers

Spring Romance

Something New/Old

With tourism down, new attractions can often help....

Light Box

A great light box built from a CCFL back light extracted from an old LCD display. Exceptionally uniform light intensity distribution across the entire surface. The colored squares are filters. It runs on +12vdc (2amps) & + 5vdc.

New Speaker Design

Snapshot of work in progress on new speakers. Intended as platform to test speakers, enclosures, ports, cross-over networks, filters, and amplifier designs.