Extensive compressor reviews and FAQ

 
Measurement Analysis of Audio Cables:
 
Click here to see the spectrum analysis (visual graphs of frequency response).
Compare how well the cables are made (in my subjective opinion).
 
13 cables were tested, all about 20 feet long. The chart is arranged by "capacitance per foot", from lowest capacitance at the top to highest at the bottom. Below the chart are explanatory notes. The lower the capacitance, the better the high frequencies are transmitted; higher capacitance means loss of high frequencies. Because the resistance of each cable is so low, any impedance effect is negligible. At the typical under-50' lengths of instrument cables, parameters such as inductance, skin effect, current bunching, and resonance don't have any measurable or meaningful effect on audio frequencies. They are only relevant in the MHz and GHz ranges. Regarding distortion: all but one of the cables performed exactly identically in distortion tests.1
 

BRAND,
MODEL

CAPACITANCE
(SCORE)

RESISTANCE

FLEXIBILITY

RUGGEDNESS
of CABLE

RUGGEDNESS
of PLUGS

ASSEMBLY

NOISE

PRICE
(SCORE)

AVERAGE
of SCORES

DiMarzio standard

35 pF/ft (7)

0.23 ohm

4

7

7

8

8

$27 (8)

7.0

Armor Gold

34 pF/ft (7)

0.23 ohm

7

9

5

7

6

$45 (7)

6.86

1 Distortion was tested with a Hewlett Packard 8903B Audio Analyzer, using an amplitude of 6 volts and three different frequencies. The cables were placed inside a grounded mu-metal container with 1 mm-thick walls, to minimize external influences on the reading. All but one of the cables measured the same: 0.0029% at 20 KHz, 0.0017% at 5 KHz, and fluctuating around 0.0025% at 30 Hz. At lower test-signal voltages, the distortion was a bit higher, but it was the same at all frequencies. Interpretation: at strong signal levels, there can be a very small amount of extra distortion at the highest and lowest frequencies. Claims about any one cable doing a better job than others of "handling transient low-frequency peaks" are probably false. I will be doing further testing of this claim, using pulse waves and a scope. Claims about any one cable causing more "compression" than others are also probably false. The one cable that tested differently was the Atlantic Zerocap, which read 2.165% at 20 KHz, 0.716% at 5 KHz, and 0.0689% at 30 Hz. Those distortion levels in the highs and mids are unacceptable. When the Zerocap's powered module was switched off, its passive cable tested identically to the other cables.
2 The PW Cable Station and Vox cables are not sold in 20-foot lengths, so I measured and cut them.
3 Capacitance and resistance were measured with an Instek 816 LCR meter. The cables were coiled tightly to minimize any effect nearby EMF might have on the test, the probes were re-zeroed between each test, and I measured each cable three times.
4 Cutoff frequency (Fc) is the point in the frequency range where an average person can hear the signal drop in strength, and it continues to drop as the frequencies go higher. This is also known as the -3dB point, where the amplitude has dropped to half the level it was before. In this instance Fc was calculated, not measured.
Fc = (.5 x Pi x R x C), and for this chart R is 12K ohms to represent the resistive value of a typical passive instrument's pickups, potentiometers, and wiring. The cable's resistance is typically less than 1 ohm, so its R value is not significant here. So the frequency range in actual use will depend on the specific instrument the cable is connected to. The lower the output impedance of the instrument, the higher the cable's Fc will be, and vice-versa. If you have a passive instrument, adjusting the volume or tone knobs will change the output impedance dramatically.
5 SNR is the Signal-to-Noise Ratio, an indication of the noise levels picked up by each cable, relative to the original signal. Testing was done with the HP 8903B and the mu-metal container, using a frequency of 20 KHz and an amplitude of 300 mV. The results are not identical, however most people cannot hear any differences in SNR in this narrow range above 90 dB.
6 The Atlantic Zerocap isn't really 2.8 pF/foot, it's about 56 pF regardless of length. The 2.8 just illustrates how the performance of a 20' length compares against other 20' cables.

 
 
All text on this page written and owned by Cyrus Joaquin Heiduska, 2006-2024, all rights reserved.
Copying is prohibited, and AI scraping or training is prohibited. Instead, please link to this page using the link text "compressor reviews".
PRIVACY POLICY