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signal loss from successive connections
Old 1 week ago
  #31
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JohnRoberts's Avatar
 

Quote:
Originally Posted by Richard Crowley View Post
As we might have expected, Google has made searching, cross-referencing, and viewing patents from the USPTO quite easy at https://patents.google.com
Yes... Back in the early days of computerized patent searches they didn't have data about very old patents, but I just checked and they now have scans going back to 1800s.
Quote:
Even my own patent is in there.
And my nine patents too...

JR

[edit: back in the day we used to pay hundreds of dollars for humans to physically search through the patent shoes (drawers). With no guarantee they didn't miss something (you had to know which shoe to look in). Now they are driving ubers. [/uber]

Last edited by JohnRoberts; 1 week ago at 07:37 PM.. Reason: add
Old 1 week ago
  #32
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The reason that this is such a polarizing question is, for lack of a better way of putting it . . . it's the wrong question.

It's my general opinion that those who are dismissive of the sonic artifacts of cable/interconnection schemes on the basis of measurement . . . either haven't really put in their time making valid measurements, and/or haven't exercised valid epistemology to correlate gathered data to real-world observable phenomena. This is complicated by the fact that the discipline of metrology (on which test and measurement practices are based) requires repeatable and duplicable results . . . and both cables and (especially) connectors have primary failure modes that are, by definition, a deficit of repeatable performance.

Quote:
Originally Posted by kywoman View Post
Signal loss via connectors - have any experiments/measurements been done to quantify the impact of connectors on a signal, as compared to a control of the same cable with no intermediary connectors? I'm wondering about basics like freq response/attenuation, SNR, etc.
I have two AP systems, an analog S1 (SYS-22A) and a dual-domain S2 (SYS-2522A). Using one of a couple fixed passive bandpass filters for the stimulus, and when combined with averaging the distortion residual on a DSO . . . either of these can make very-low-level THD (the averaging differentiates this from THD+N) measurements that easily exceed even a new APx555 . . . albeit tediously and only at 1KHz and 10KHz. With this method, I can indeed confirm that if one is only concerned with repeatable data points, any common analog audio connector of reasonable quality, correctly used in application, in good condition, when properly mated . . . delivers wholly transparent performance.

Quote:
Originally Posted by kywoman View Post
I can't imagine any single person has taken the time and expense to do something like this, but perhaps an institution, company or academy has? Anybody know of anything like this, or in the similar ballpark?
This is precisely why military- and aerospace-grade components are so expensive . . . their certification requires a large sample size of identical pieces put through rigorous stress tests, so that their performance can be analyzed statistically. Put another way . . . the data points that are most relevant in the field are those that are not repeatable . . . precisely those data that are thrown out in metrological common practice. As a result, the testing methodology needs to be adapted to focus on the products' technical limitations that are of greatest likelihood and concern to their field use.

Quote:
Originally Posted by kywoman View Post
Let's say you had 10 pairs of male/female connections on a single cable (or 100!). No confounding variables like dirt/tarnish on connectors, sloppy soldering jobs, etc. Just decent cable with established and published specs with a bunch of Neutrik NC3M(F)XX in-between. How does this measure up against the same cable of similar length but only one pair of connectors, or none at all?
This is precisely the point where we need to consider the logical problem presented with defining the question in this way. If we use the yardstick of established reliability and failure rates . . . then whatever the probability exists that a single series-mated pair of soldered Neutrik NC3FXX/NC3MXX connectors, when used in application over their lifetime, will cause either a measurable or audible artifact . . . putting one hundred of them in series will increase this probability by exactly two orders of magnitude. Period.

I personally measure, with test equipment, interconnection-related artifacts in the distortion residual on a very regular basis. Not just occasionally, or a bit here but there, but all the friggin' time. With experience on the bench, it usually takes mere seconds to identify a dirty connector, loose or poor termination, sensitive grounding hookup, etc. etc. . . . and then one corrects the problem and gets on with it. These are not just when performing extremely low-level measurements . . . we're talking overt, obvious noises and distortion numbers up by orders of magnitude. But they do seem to often occur at a level in that wide gulf that exists between "instantly obvious" and "almost undetectable" for both audibility and measurement -- difficult to quantify without specifically targeting it for observation either by ear or with test gear.

Quote:
Originally Posted by kywoman View Post
Perhaps most importantly, how much more of an impact would these connections have when occurring between a mic and preamp vs. after preamp (or other source amplification)?
From what I've observed, an audio connectors' performance doesn't show differences that correlate with these two general parts of the signal chain . . . perhaps this is why the industry uses the same type of connector in both places. Obviously, a connector that's more prone to physical abuse will tend to have a higher failure rate . . . but the same one in a more oxidizing/corrosive environment might have a lower failure rate if it's plugged/unplugged on a regular basis.

In short, the whole reason for having connectors at all is to facilitate the use of cable systems in a way that makes them useful in their environment and application. Thus, the more narrowly the environment and application can be defined . . . the better the validity of any data or conclusions made about their performance.
Old 1 week ago
  #33
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Paul Gold's Avatar
Bravo. The difference between metrology based measurement and statistical analysis explains why connectors are a mature technology that is understood by all and shouldn’t be questioned and the reality that connector failure is the most common failure in an audio system.
Old 1 week ago
  #34
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gyraf's Avatar
 

Quote:
Originally Posted by kirkus View Post
. . the data points that are most relevant in the field are those that are not repeatable . . .
Thanks. This clicked it into place for me.

Jakob E.
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