Since the Pioneer SX-434 is working so well, thanks in part to advice I recieved here, I'm going to hang the speakers in the shop and use it. One speaker will be about two feet from the SX-434 while the other will be 30 feet away. Will it make that big of a difference if the speaker wires are of such different lengths? I have enough speaker wire laying around that I could make them both the same length. I could just coil up the wire to near speaker. Thanks, Eric
If the wires are heavy-gauge, it shouldn't make any difference. If they're thin, yes, you might hear a difference in bass output (maybe). I would make them the same length.
How many uh inductor is your speaker wire coil going to be? ;-)
On a note I found interesting; The local marine tech was here at the marina to do a welding repair on a boat. For some reason he could not get the welder to work properly. The problem turned out to be the excess cable was wound up and piled on his trailer, making an inductor. The inductor was enough to limit the High frequency current. He straightened out the cable and all worked well. Another thing I found odd, the High frequency was generated using a spark gap. Seems so old tech, but I guess it is still common in welders. Mikek
If it is just background music, then you can use almost anything on hand. If you are going for music quality with some volume, then minimum
18 gauge.
Louder? 16 gauge.
Stadium? 00 gauge. (right...)
John :-#)#
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What you saw most likely was the arc starter at the tip, which means it must of been a tig welder of sorts. The arc is generated at the tip down on to the work piece where it can create the plasma needed to create a conductive path to the work piece for the main current, which in most cases is high frequency from an inverter.
It's more likely there will be a difference noted due to the distance involved in the physical separation. IF any difference is noted at all. I believe the human ear is more sensitive to time differences than intensity differences.
The ear/brain system can be sensitive to inter-aural timing differences down to a few microseconds... it shifts the left/right positioning of the apparent sound source. For timing shifts of this magnitude to actually be audible, the rest of the timing needs to be stable and fixed - e.g. you need to be listening to the two signals via headphones. I used this trick to do a simple "one-channel sampled sound, to two-channel pseudo-3D-sound" DSP system for a videogame system design back in the 1990s.
30' of wire would work out to under 50 nanoseconds of added delay... this is well below any timing shift that I was ever able to show resulted in an audible shift of apparent position.
In addition, if you're listening over loudspeakers, even a tiny change in the location of your ears (with respect to the speakers) will introduce more more timing shift than this. The speed of sound in air is roughly a million times slower than the speed of electricity in a wire.
One effect of a "too long, too thin" speaker wire that I don't think has been mentioned in this thread is that of a shift in the speaker's effective frequency response. Speaker systems almost always do not have anything approaching a constant impedance... it's quite high (tens of ohms) at the resonance frequencies of the drivers, and low (roughly the "nominal" impedance) at intermediate frequencies.
Throw an ohm or two of speaker-wire resistance into the mix, and the speaker's output may be attenuated significantly (a dB or so?) at some frequencies where the speaker's impedance is at a minimum, and attenuated very little at the driver resonance frequencies where the impedance is high. This might, possibly, make a perceptible change in the speaker's tonal balance.
For most speaker systems with wire runs of reasonable length, using any halfway-decent (i.e. inexpensive) 12- or 14-gauge stranded speaker cable should be all you need. Any tonal shifts or other effects due to its resistance should be well below audibility, and a lot less than (e.g.) changes in the driver stiffness due to humidity changes, or changes in your own hearing due to exposure to noise during the day, caffeine intake, etc.
What is your evidence for this? Above about 1kHz, the brain doesn't recognize phase or timing differences. Audible differences are likely in the range of tens to hundreds of microseconds.
As for the question of the speakers being at different distances... If you're trying to get a stereo image with one speaker ten yards farther away than the other... who cares what kind of wire you're using!
"Ten or less" is the figure I see published in a number of sources. That's the range I was thinking of when I said "a few". I didn't mean to imply "single digits". This was the sort of number I found in the references I first looked up when I worked on the "pseudo 3D sound" idea back about 20 years ago, and my experiments at that time seemed to agree.
In the case of frequencies below 1 kHz or so, this timing difference has the effect of shifting the phases of the signals arriving at the two ears. The ear/brain system is definitely capable of detecting small phase differences in frequencies in this range... phase shifts corresponding to 10-15 microseconds are quite audible. The brain is capable of detecting such phase differences in medium-frequency sounds, even when a sine wave having this time as its frequency would be too shrill to be audible at all. There's apparently a "delay line and coincidence detection" architecture in the nucleus laminaris that makes this possible. (Wikipedia article on "sound localization" has some details and references to this).
In the system I put together, a single sampled-sound recording was being fetched and played back by two independent data-grabbers (pulling samples out of a circular memory buffer at different rates and offsets). It used a simple linear-interpolation system to synthesize sample values between the ones in the buffer... so, in effect, it was able to resample the input data on the fly and introduce variable amounts of phase shifts between the two playback channels. Interaural delay, and Doppler shifting could be simulated. (Yeah, linear interpolation isn't a hi-fi way of doing this, but it was cheap to implement in a little flea-bite DSP that we could tuck into the corner of the ASIC).
If I recall properly, the variable-rate sampler was able to sub-sample down to 1/16 steps between the original samples. We normally used CD-quality samples (44 ksamples/second). The time offset between original samples was thus around 22 microseconds, and we could fine-tune the offset between the two playback channels (ears) to within 2 microseconds.
A full one-sample offset between the ears was quite audible over headphones on a lot of program material. A single 1/16 sub-sample offset (under 2 microseconds) was not. The point at which you'd begin to detect a shift in the sound's apparent left/right position, as the offset was increased, depended a lot on the program material. It's been a long time since I ran the experiments, but I believe I remember that the threshold was usually somewhere in the 5-8 microsecond material (for my ears, on my test setup, with test audio I was very familar with).
The fact that we were subsampling allowed us to "move" a sound from left to right smoothly (or Doppler-shift it, or both), without causing audible ticking and popping as the result of sudden full-sample jumps in timing offset.
Blauert's classic text "Spatial Hearing" is a good reference for this sort of thing. You can find a bunch of others cited in U.S. Patent
5,337,363 which is the one which came out the project I worked on.
I said "phase or timing differences", when I should have said "phase". Above about 1kHz, phase differences are not used for directionality. This is fact (read any book on acoustics). I confirmed it 44 years ago when I used an oscillator with fixed and variable-phase output feeding stereo headphones.
"Since the Pioneer SX-434 is working so well, thanks in part to advice I recieved here, I'm going to hang the speakers in the shop and use it. One speaker will be about two feet from the SX-434 while the ..."
To discussions of wave propogation, which is better left to the Russians actually, and totally ignor ethe fact that even if you could hear the difference, there are a hell of alot of people who just don't care...
But you see, just how close this is to quantum mechanics ? I mean, this whole thread is only a few days old, or new, depending on your particular conception of time, in most countries.
Next, people are going to wonder where those extra electrons went out of their speaker wires, which were insulated and everything.
They escaped to the Hendershot of course and are providing air conditioning fork someone in Cape Forward, Chile.
** But time of arrival for any transient is CRUCIAL !!
** Phase differences are not heard on headphones at all - with *SINE* waves.
But with speech, music and other real sounds, reverse phase is VERY obvious.
It is less obvious with speakers, one must be near the centre of a stereo pair and in a room that is not too reverberant or it can be hard to tell between "in" and "out " of phase. But the we are dealing with VIRTUAL images of real sound.
With REAL sounds, in the three dimensional world - recognition of sound direction is normally instant and accurate.
Agreed on the time vs amplitude but the time differences in speaker cable l engths are in the 10s to maybe 100s of nanoseconds. I ASSURE you you will n ever hear fractional microsecond differences.
When I got my first CD player (CDP-101) it had a single D-A converter so th ere was a 45 degree phase shift at 10 KHz. Keep in mind it's not a 'phase s hift as much as a time offset (45uS). Translating that to path length in ai r it works out to 0.15 inches so the question was, if I turn my head to 'ma tch' the path lengths, can I hear the difference? The answer is no and I se riously doubt anybody can.
When I got my first CD player (CDP-101) it had a single D-A converter so there was a 45 degree phase shift at 10 KHz. Keep in mind it's not a 'phase shift as much as a time offset (45uS). Translating that to path length in air it works out to 0.15 inches so the question was, if I turn my head to 'match' the path lengths, can I hear the difference? The answer is no and I seriously doubt anybody can.
** Have you still got your CDP101 ??
I ordered one soon as they became available in Sydney - the dealer said I was the first to pick one up in May 1982, IIRC.
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