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  1. 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...
  2. 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...
  3. 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...
  4. 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...
  5. 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.
  6. 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.
  7. 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/
  8. 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...
  9. 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...
  10. 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...
  11. 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...
  12. 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...
  13. 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...
  14. DonH56

    multitone spectrum proposal

    A single sine wave of 4.47 Vrms yields 5 W into a 4 ohm load. If you look at the individual amplitudes of 32 tones they are much less, thus the lower number provided for that case, but the RMS value will still be 4.47 Vrms for the product of tones. Setting the display to 0 dB for individual...
  15. DonH56

    multitone spectrum proposal

    Too late. ;) You are comparing a single tone producing 5 W to 32 tones producing the same 5 W average power. Your conclusion is not valid because the math is not linear.
  16. DonH56

    multitone spectrum proposal

    The AP, like most if not all audio analyzers, measures voltage and calculates RMS values accordingly. Conversion to watts comes from knowing the load resistance, then P = V^2 R which provides average (not "RMS") watts. With a purely resistive load it is watts, not VA, since a resistive load has...
  17. DonH56

    Delicate higher harmonic frequencies vs wire Gauge no measurements on this subject...

    Without rapid switching AB(X) testing is of questionable value. Auditory memory is too short, ~6 seconds IIRC. Yes, the cables very likely contribute enough to mess up the levels. For a listening test, levels will need to be matched, which can be a challenge. The problem is that, while we can...
  18. DonH56

    Delicate higher harmonic frequencies vs wire Gauge no measurements on this subject...

    10 feet of 24 AWG is 0.5134 ohms; 18 AWG is 0.1277 ohms (for two wires, plus and minus)*. That is a significant difference, natch, though audibility also depends upon speaker impedance variation. Into 8 ohms, the loss for 18 AWG is about 0.14 dB and about 0.54 dB for 24 AWG, a difference of 0.4...
  19. DonH56

    Delicate higher harmonic frequencies vs wire Gauge no measurements on this subject...

    Smaller wire (higher AWG number) is higher in resistance so is more likely to attenuate the sound. Assuming the effect is real, I suspect what is happening is that the 24 AWG wire is actually attenuating the lower frequencies more since most conventional speakers have impedance dips down low and...
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