Recent content by DonH56

  1. DonH56

    Slew Rate

    The first post of this thread notes the simple slew rate equation is for a single-frequency sine wave. That is the maximum slew rate which occurs around the center (zero-crossing) of the signal, and slew rate decreases as you move away from that point. There is a chart in the first post from...
  2. DonH56

    What is the impact on amplifier power / SPL from filtering out low frequencies - crossover, subwoofer, LPF

    Typo; looking at the original, should be 100 W at 50 Hz, if I read it rightly. Not at my computer right now but the rule for power is a 10 dB increase requires 10x the power, 20 dB 100x, 30 dB 1000x (goes as 10^(power in dB/10) ).
  3. DonH56

    Shielded speakers cables

    Unless you have severe RF interference, shielded speaker cables are unlikely to do anything sonically, and increase the risk of accidental shorts. As for the connections, much depends upon the amplifier topology. Some amplifiers cannot handle a grounded output terminal (either terminal, plus or...
  4. DonH56

    What wire to build my own RCA interconnects?

    What you and @SIY said and I want to third the statement in bold. It is not something worth considering for audio frequencies. RF Impedance is irrelevant at audio frequencies. The only thing that matters is resistance, inductance, and capacitance (RLC) and for interconnects among local...
  5. DonH56

    What wire to build my own RCA interconnects?

    25 ohms!?!?!?! Have not heard that, but since there are so many different "flavors" of RCAs, who knows? The ones I have measured have been around 75 ohms but it was originally designed as an audio, not RF, connector and so RF impedance was never part of the original spec AFAIK. Not until they...
  6. DonH56

    What wire to build my own RCA interconnects?

    RG58 is very similar to RG6 (or RG59) and is essentially equivalent for audio cables. RG6 is very commonly used for video cables, has slightly less loss at RF frequencies (decades above the audio band), and handles more current, mainly a consideration for satellite dishes that send DC along the...
  7. DonH56

    Big test of 13 op-amps in inverting configuration with gain = -1 and non-inverting configuration with gain = +1

    Yeah, and even worse because the 1 kHz difference tones (at 18 and 21 kHz) are related to the third-order harmonic term so 60 kHz is also important. But it very much depends upon the circuit to determine the amplitude of the terms.
  8. DonH56

    Soaring

    One thing I am curious about is how hard it is to see other aircraft since I assume you are under VFR? How crowded is the airspace? I'd be really nervous about missing a nearby aircraft.
  9. DonH56

    Big test of 13 op-amps in inverting configuration with gain = -1 and non-inverting configuration with gain = +1

    IMD directly correlates to THD so no real need for a separate test. Explaining how and why IMD matters is a worthy subject; here is a start: https://www.audiosciencereview.com/forum/index.php?threads/harmonic-and-intermodulation-distortion.25436/
  10. DonH56

    Big test of 13 op-amps in inverting configuration with gain = -1 and non-inverting configuration with gain = +1

    Nice work! Is 1 k-ohm a reasonable load for all of these op-amps? I do not know, curious, knowing 10 k-ohm is a typical lower value for most audio inputs (sans the unbuffered class D amp modules). I calculate 1.9 Vrms is about 2.7 Vpk so only about 2.7 mA (not accounting for any capacitance and...
  11. DonH56

    Some elementary Matlab programs to test your system.

    I think this thread targets folk who have moved a bit beyond "Hello World" in Matlab...
  12. DonH56

    Phase alignment

    Yah, done that, usually poorly. Much easier and better results using the proper tools. Now that means a $100 UMIK-1 and free REW software; back when I started, it was about $10k worth of equipment and professional analysis software. My usual simple technique was to play a tone at the crossover...
  13. DonH56

    Phase alignment

    AVRs, at least the dozen or two I have owned, include a delay adjustment for time alignment. Phase alignment usually happens via the processor (room correction) program. There are many proponents of aligning the subs so the AVR/AVP treats them as a group. Strong opinions on both sides, group...
  14. DonH56

    Phase alignment

    The RN1000A has only a single subwoofer output. Using a splitter to add a second sub means you will have to manually adjust the new subwoofer to align it with the other sub and the rest of the system. It will treat the two as a single subwoofer, which will not in general give optimal results...
  15. DonH56

    Buckeye Amps: New US based Hypex multichannel amplifier builder, line-up announcement!

    Tariffs are protectionist, favoring local manufacturing, but of necessity inflationary when so much is imported. We pay large tariffs to other countries, probably far more than most folk realize. For decades companies for whom I've worked have been dealing with tariffs from the other side (as...
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