Recent content by tucura

It was impossible for me to get a copy of the Extigy original CD. I managed to measure with sufficient accuracy (not much needed) the input impedance of the crossover using the mono input of a USB audio card, a power amplifier and a 100 ohm resistor. Also REW in the SPL measurement mode...

Good point! I will try to look into your suggestion. I will try with Windows 98 running inside a VirtualBox.

thank you Steve!

Surprisingly (for me!) the Macbook Air doesn't seem to have an external microphone input. Using a simple USB headphone/mic interface and a 100ohm resistor driving the LC parallel tank I managed to verify resonance using the SPL mode on REW. Resonant frequency shows now located at ~900Hz as...

I am amazed of how clean the curves are: I have never, under any circumstance, managed to get such a clean plot. Before I attributed my noisy plots to measure the speakers in a noisy room, now I understand there are other source of problems.

The Mac doesn't have stereo inputs. At this point I am not interested in measuring impedance with any precision, only care about frequency dependent issues. And a 6x error in the evaluation of the resonant frequency of a simple LC tank make this task impossible. My next step is to evaluate the...

Thank your NBPK402!

Thank you Todd!

No, I don't sell any products. I designed a cabinet using some old (but good) Seas P14RCY speakers I have, and I am also working on the design of a power amplifier (currently waiting for parts). In the past I designed a 250W/Channel amplifier...

The Midi Setup shows sampling rate for Extigy card as 48kHz, both line input and output, same as used on REW. I changed to 96kHz on some of the tests to see if it had any impact on noise, but most tests were done on 48kHz.

Additional test using 10ohm only and 10ohm//25uF with Extigy card only and 48kHz sampling rate. No filtering. Test with resistor only shows low noise. Test with resistor//capacitor very noisy. Test repeated several times with same result.

Please find attached the calibration run using Extigy card only: Rsense = 60 ohm, Rtest = 10 ohm, Fsamp=48kHz

I will test again and attach the mdat file later today.

The sampling rate can be set only on REW. I repeated all measurements after setting the sampling rate to 44.1, 48 and 96kHz. Results look all about the same. It was my fault not to include the calibration files in a previous message. This plot here corresponds to 48kHz sampling rate, 60ohms...

I managed to use the Creative Extigy card only, plus a power amplifier driving the impedance measurement jig. The results are the same. I have further made some additional tests using a 10ohms resistor in parallel with 25uF capacitor. The attached results using 1/6 smoothing suggest some...