elduderino

(I don't know if this helps anybody, but I've seen a lot of terms slung around, and I wanted to try to define some of them. Best of luck out there.)

"Engine noise" is really alternator noise. The alternator in your vehicle cranks out AC electricity, and the rectifier on it changes the AC to DC electricity that can be stored by the battery. Unfortunately, no rectifier is 100% effective, and the rectifiers in alternators are nowhere near 100% effective. What that means is that your DC electrical system has faint amounts of AC "floating" around it.

This usually doesn't hurt anything, unless the rectifier fails completely, but then it's a pretty tremendous catastrophe. But unfortunately, since Edison abandoned the completely mechanical gramophone that worked with a toothpick and a horn, audio systems have used low-level AC to "mimic" the air pressure changes that we hear as sound.

The low-level AC signal goes into an amplifier and gets made into a high-level AC signal strong enough to push a speaker in and out (using the speaker's magnet as a fulcrum - but I digress). But before it gets there, in certain conditions, the AC floating around your car's electrical system can get added to the AC signal heading for your amp. This is why, when you place a greater load on your alternator by turning on your lights, cig lighter, or rear-window defogger, your noise gets louder.

And that's "engine noise". (And you now know more than everyone at Circuit City, but regardless...: )

There are really three kinds of engine noise:

1) The kind that is created inside the component due to poor power input filtering. The AC coming in the unit's power wires somehow ends up on the audio output. This is usually bad design. This is rare, and don't assume bad design, cause it's usually bad installation. This can usually be addressed by filters on the power wire. This is only the case nowadays with crappy gear. BTW - if the head unit diodn't have noise before, and it has noise after you add an amp, you can pretty much tell that this isn't the problem. If you have a signal processor (Xover, EQ, etc.) sometimes they need more filtering.

2) The kind that is picked up by your RCA or signal cables between two components. This is called inducted noise. (Technically, you an get inducted noise on your speakers too, if you place one of your speaker crossovers next to a power wire and the coil of wire in the crossover is next to the wire and acts like a super-long antenna, but that's pretty rare.) This is fairly common in Honda-based vehicles, and all the kinds of "shielded" RCA's never helped one car I ever saw. However, twisted-pair signal cable works great! I can't tell you how many cars had their noise eliminated with this simple addition. It's all I use now - even the entry-level twisted is better for car use than the most expensive straight-conductor RCA's.

3) Ground loops. I will not even try hard to explain ground loops (they basically mean that there is a difference in how easy it is for electrons to loop back to the battery - for one of your components, fewer electrons can make the trip. The electrons look for a way to get home - back to the battery, that is - and they end up making the trip on some audio signal cables somewhere. There, that's all you get - if it didn't make sense, too bad : ) Here is how you go about getting rid of them:

Ground all components to the same point, with no paint under the connection, and under a bolt rather than a screw if possible. Bad grounds are the single biggest cause of engine noise.

Make sure your battery is in good shape. Weak and low batteries fail to do their job of filtering AC like they should.

Try RCA's that are only grounded at one end. (Hey, it might work...) Also, if you have a signal processor, try lifting the ground for it and see if it makes a difference.

Try a ground-loop isolator. Most of these make your system sound worse, especially in bass response. They often get the noise out though. I usually use them for troubleshooting more than for installations (the one in my tool box has been there for years).

If you are using a factory head unit, whether it's low-level pre-amp or high-level speaker-level output, you are more likely to have noise. Here it gets somewhat mystical. Good high-level Line-Output Converters are usually a great way to get good results on high-level installations. I really like the AudioLink brand (AAMP sells it with their label on it). I used one of these in a Scion demo car for CES and had no noise, for instance. I have seen others on this thread say you "have" to use LOC's even on low-level output decks. I don't think this is a "have-to", but I think the reason this might work sometimes is that the LOC acts as a Ground-Loop Isolator (GLI). Since GLI's come with RCA's on both ends, it's hard to insert them into a factory-to-RCA installation. Again, often LOC's degrade sound quality (even slightly), so I wouldn't insert them if I didn't absolutely have to.

e_lectro

Not a bad write up, but I have some comments and several things to expand upon.

Grounds:
When grounding everything together, do not ground the headunit with them... it's just to long of a run to be helpful. Instead find a better ground up front, and ground the chasis of the radio to a part of the frame. Do not count on the ground conductor in the wiring harnes to be a good ground.

Also, keep your grounds short. If they need to be longer, step up to a larger cable size to make up for the increase in resistance from the cable length.

RCA Cables:
I won't start the whole twisted vs. shielded, its still a source of huge debate in the forums at caraudio.com. I have seen tests show both are best at rejecting induced noice. I say buy what you want, and if you're not happy, try the other.

OEM Deck quality:
From David Navone
LOCS:
They are not designed for or useful on low level signals, they will just further reduce the output. Those who have said to use them here when removing the amplifier or on low level signals are misinformed or confused. If you are taking the signal after the factory amp, you need a LOC. If you are taking the signal before the facory amp, all you need is a cut up set of RCA cables.

But I do agree with you on the GLI's. Some people always try and use them as a qick fix. They would rather go out and buy one of those than spend the time actually fixing the problem (bad ground, cable route, etc). They should be a last resort.

-e_lectro

elduderino

Good point on the ground - what I SHOULD have said is "always run a ground wire from the head unit to the amp, along with your RCA's and PTO lead. Then, if you need it, it's there, but if you don't, no harm done." Often they've helped, occasionally not, but most of the time it's a null.

On the twisted pair, certainly don't want to get into theoretical debates about that topic. Between 1986 and 1996, I gave up telling people to buy "shielded" RCA's. I'm sure that many installers remember how often a $1.99 cheap black RCA got rid of noise that a $29 set of "high-end" RCA's seemed to introduce. Then I tried twisted pair. The results were so impressive in Hondas (I manages a shop for a while where the installers, on my first day, got mad because I scheduled an appointment for a Civic Si with engine noise. "It's a Honda - they have noise- nothing you can do!" they said. Twisted pair got rid of it. I'd rather use a pair of Radio Shack RCA ends on twisted pairs of doorbell wire than I would an expensive Monster, Phoenix, or Lightning, or Esoteric set of straight wire cables (if they make such a thing anymore).

I certainly wouldn't engage in any sound quality debates (because I think that sound quality in a car is not affected by cable 999 times out of a 1000). As far as my theoretical understanding goes, if you have a straight wire, it can act as an antenna. You can shield that antenna all you want, but it fundamentally still has those antenna characteristics - it WANTS to pick up certain EM frequencies out of the air. If you twist the wire, you are actually changing its shape into one that lacks those antenna characteristics (at least at the freqs we care about) and so the shielding can be much more effective, because the wire's "sensitivity" is that much lower. That theory could be wrong, but my empirical results are what I base my recommendation on - when it comes to cable, theory to me is only good for explaining empirically-observed results - otherwise, it's wanking. (Or maybe I'm just bitter at all that expensive cable I sold customers that turned out not to help - then I felt like an ass for believing the factory rep, AND I had to get rid of their noise myself!)

biker

Nice write up but who's got engine noise problems?

elduderino

Thanks.

I assume you mean besides

http://acura-tsx.com/forums/showthread.php?t=9278

http://acura-tsx.com/forums/showthread.php?t=9239

And the many discussion of noise in iPod and AUX-in applications... : )

biker

I meant anyone that hasn't modified their audio system. Anytime you mess with something that works fine there's possibility of screwing it up.

e_lectro

And you think he was directing this to someone with a stock audio system?

Bass Mechanic

great write up however i see a couple small items that are incorrect.
actually there is no AC in the system at all. yes the alternator makes AC but the full wave bridge rectifier in the alternator turns the negitive AC cycle upside down and what you end up with is nothing more or less than a pulsating DC wave just like the sine you started with except that there is no more negitive cycle in the sine wave. (it's now positive) the alternator whine you refer to is in fact because there is a static battery voltage of 12.8 volts and the alternator's RMS output voltage is = to 14.1v-14.2v usually depending on the alternator. what you have is an electrical system that is running at 12.8 but has positive bumps in it that peak at 14.2 volts. in other words it fluctuates between 12.8 and 14.2 volts
actually it has little to do with the filtering of the power input side of the amplifier this is easily prooved in any amp by simply unplugging the RCA cables from the amp. 99.999% of the time there is no engine noise to speak of when doing this.
as soon as you plug in the RCA cables you will get noise. the reason is because not every manufacturer designes their input stage of the amp to compliment the output of another component. some amps have a floating ground while others have a common or chassis ground. this is where the term called "ground loop" came from it has nothing to do with anything "looping" its simply the fact that you have in input ground at reference voltage say 5 volts and another at voltage 0. connecting an RCA cable between these 2 components together forces the ground of the floating ground or the 5 volt device to be forced to reference ground 0 or chassis ground. in the old days re grounding or moving to a better ground might or might not solve this problem. forcing the component with a higher than 0 floating ground will cause a DC current to flow down the RCA cable.
it makes noise because since the DC voltage of the electrical system is fluctuating between 12.8 and 14.2 volts. so is the reference 0 of the input side or (rca) of the amp. since the signal is changing so will the output of the amp. it's simply amplifing the signal it was given in the first place. usually in this case the only way to resolve the problem is with a GLI because it will allow each component to have separate reference 0 voltages because by using a transformer they are electrically not connected to each other any more. in fact the only thing that can be transmitted between the 2 devices is an AC signal because they are transformer coupled.
well back in the day i would have agreed with this statement. while twisted pair is better for noise rejection it also introduces capacatance to the RCA cable. adding a capacitor to a preamp signal like this will effectivly filter out anything below a certain frequency. depending on how twisted the cable is the more capacatance you will have. if you want the best of bothj worlds try using some CAT-5 cable used for networking. it's not twisted, but rather braided it will still have capactance but not as easily as twisted pair cable will.
as many installs as you have done that twisted pair took out noise i could name 100 more i have done while running the RCA cable in fact wire tied to the power cable and had 0 noise. it has more to do with using quality components than it does with running the RCA's near power wires. you need to worry about staying away from factory wires in the car and engine computers as well as high current type wires such as a fuel pump more than you need worry about running along other wires. also always try to cross another OEM power wire at a 90 degree angle rather than paralleling it.
i already touched on this earlier. a GLI is actually a very effective solution to eliminating alternator whine. if you cant eliminate it by reconfiguring your install then usually this is a last resort. i wouldnt say that it will loose any part of the frequency responce low or high. if its a quality one than i say use it. however as you mentioned it will pick up noise easily if its not located someplace void of any electrical interference because ANY power wire for any component will pick up the inducted noise through the transformer windings of a GLI.
probly the number 1 reason people have engine noise is because they dont know how to set their gains on their amps. you cant take a 2 volt output signal from a HU and crank the input gain of the amp to .5 volts sensivity. people think they are volume controls on the amp and they arent. also with the newer amps and HU's comming to the market many are sporting a 4-6 sometimes 8 volt preout. this isnt necessarly cleaner output or more dynamic as some might argue, having more output signal allows you to run your amps with a much lower input gain setting. therefore any background noise is noticed less or not at all with reference to the signal being amplified.

also in any install i do i NEVER ground the amp in install to the chassis. many times an amp will have metal tabs on it that when you screw it to the car you have made an additional ground point. i prefer to mount the amp to a peice of carpeted wood (to make it look nice) most good amps arent electrically connected to the case but its always a good idea anyway. it usually takes me less than 5 minets to make with a table saw and the sprayglue and carpet sitting nearby.

slo007

I think you are wrong here -- as it's definitely not the case in my car. There are huge amounts of engine noise in the audio w/o the LOC (OEM amp bypassed). The LOC in my setup increases the voltage of the signal, thereby reducing noise (up to 99% in my setup).

Without an LOC, or similar device, I could not hear music.

Bass Mechanic

most LOC's are nothing more than a few resistors to simulate a load to the output of the amp. then the signal goes through a transformer that steps down the voltage of the signal to be used for a preamp or RCA signal.
i suppose if you used one backwards it may boost the signal a little but i think you would be better off with a GLI because it is pretty much the same thing except it is a 1:1 transformer.

e_lectro

In this case you must be using the LOC in the place of a GLI and Line Driver. This is not what it is ment to be used for, and your results would be better with the other products.

elduderino

Thanks for the comments. Here are my responses.

actually there is no AC in the system at all.

Technically your statement above is true (just like it's true that electrons travel from the (-) terminal to the (+) terminal, even though "current" is almost universally taught as "flowing" the other way.

In order to truly be "alternating" current, you have to go from (-) voltage to (+) voltage, crossing the 0 volt line on an oscilloscope. The noise "riding" on the signal doesn't cross the "0 volts absolute" threshold - it is only alternating relative to the signal it is riding on. Therefore it should be technically referred to as "clamped DC with high-frequency ripple". I think my explanation was more accessible but I did use a term in too loosely a fashion.

As far as the comment about the variations in voltage creating the noise, if you think about it a bit, the frequency of any noise associated with varying voltage would be far lower in frequency than "engine noise" is... engine noise is associated with alternator RPM, not with changes in alternator RPM. So with the change in my explanation on AC versus clamped DC ripple, I stand by my explanation.


In thinking about this
actually it has little to do with the filtering of the power input side of the amplifier

I didn't say "amplifier", I said "component". It's true that in most amps today the power input filtering is sufficient. Those of us from back to the day know that this was not always the case with amps. It is definitely possible for poor power input filtering to intrduce noise with cheap-and-sleazy line drivers, or processors, or even head units (although not a topic on these threads... I bet an iPod could get noise through a cig adapter with crappy filtering!) Anything with a power wire can have this issue.


<Your discussion of ground loops> I don't have any diagreement with your statements about ground loops, except that it sounds as if you are trying to say that ground loops should replace one of my categories, and I would have to politely disagree.


well back in the day i would have agreed with this statement. while twisted pair is better for noise rejection it also introduces capacatance to the RCA cable.

As you well know, all cables have capacitance. Someone could get the idea from your statement that non-twisted cables lack any capacitance, but I'm sure you didn't mean to give that impression. If I listen to the system and it sounds great I'm not worried about the capacitance - we are not trying to drive reactive loads like tube amps here : ) The maker's choice of dielectric (insulation) is more impactful on capacitance than twisting is.

+as many installs as you have done that twisted pair took out noise i could name 100 more i have done while running the RCA cable in fact wire tied to the power cable and had 0 noise. it has more to do with using quality components than it does with running the RCA's near power wires.

I don't mean to offend, but we used to have a term for installers that ran their RCA's and power together... and it wasn't "hard-working and industrious". Once noise is inducted onto your RCA's, it doesn't matter what quality-level of gear you have - you will hear noise. Once it's on the damn wire, it's on the damn wire. Your statement about how you can name 100's of installs to my one is A) sort of juvenile "whose-is-bigger" sounding, and B) indicative that you did a LOT of what I would consider (in my shops) poor-quality installations, and C) Probably not true. But it had a nice ring to it : ) I back you 100% on running wires at right angles rather than parallel.

i already touched on this earlier. a GLI is actually a very effective solution to eliminating alternator whine.

Yes, they are definitely effective. They are also effective at reducing sound quality and bass response a lot of the time.


also in any install i do i NEVER ground the amp in install to the chassis.

Not sure I understand what you mean, as I am sure you always ground the amp to the chassis of the car. Maybe you meant that you never grounded the chassis of the AMP to the chassis of the car. Some amps did seem touchy about this, but fewer than advertised IME. Yeah, it doesn't take long to slap chia-fur on chipboard.

Peace, out, BM.

Go Pistons.

slo007

I tried a number of GLIs before getting an LOC. The result was awful! Lots of high-pitched noise.

I plan on getting a line driver as soon as I get a job. (just finished grad school) Meanwhile, the cheap PIE LOC works ok. I just get some random hic-ups every hour or so from the tweeters.

elduderino

Actually, after speaking to an EE who designs 12V AV gear, I'm told that my use of the term AC was fine, and that my explanations are all fundamentally sound. So, neener-neener.

Bass Mechanic

neener, neener? was this a contest?

and as for the comment of the AC comment being fundamentally sound, unless you can show on an O-Scope any waveform that has a duty cycle of a positve and negitive output that alternates at any frequency in a DC circuit your friend gets a gold star.

you cant even say that there is an AC waveform riding on a DC in this case because there is nothing of the sort present in this application.

what you can say is that an automotive electrical system has a constant DC output whos charging system has a pulsed DC charge cycle.
nothing more and nothing less.

to have alternating current you must have voltage that changes polarity in equal and opposite directions with respect to reference ground 0. this could certainly be an AC wave form riding on a DC wave but it cannot be considered AC unless it is equal and opposite in phase.
in an automotive environment you have a constant 12.8 volts with a rise to 14.2 in the last 1.4 volt rise of a sine wave. you would only see the 1.4 volt difference and for the very top of the sine wave. you would never see 1.4 volt difference going negitive from reference of 12.8 volts or reference of 0 with respect to the sine. (since there is no AC)

tell your friend he needs to re-read his study book from EE class, this is basic electronics.
and for the record with your understanding of electronics this far i was under the impression you actually had some kind of formal EE traning. but not since you had to consult with a friend for info to try to prove your point.

my guess from the sounds of it either he didnt understand the question or has no idea what he is talking about.

from your post i can see im talking to somone with limited education on the subject, my 16 years of installation experience and my education in EET tells me your the sort who just likes to be right. i didnt know we were in some sort of contest to see who knows more than the other.
i was about to commend you on your knowledge on the subject in this thread and give props to someone who can speak about a subject matter that is above most i have met in the 12 volt industry.
now i take it all back.
sorry

elduderino

Go breathe into a paper bag, pal. If you couldn't see "neener neener" as humor and nothing else, you need a beer.

Don't think I represented myself as a 12V EE design engineer. I see no shame or fault in my asking for advice from someone else.

As far as qualifications go: Qualifications don't replace results. The biggest fool in the world can say the sun is shining, and that doesn't make it dark outside.

If you want to compare qualifications, sure, fine, but I don't think that that has anything to do with helping people get rid of engine noise. Telling them to run their power and RCA's together is just irresponsible.

I'm just trying to pass along useful information - not to you, but to people without your experience. If you have nothing useful to add, scoot.

Bass Mechanic

how is that irresponcible, i didnt suggest it to anyone, i just said i have personally done it in the past many times with noise free results. sure its not reccommended but if i got results that produced no engine noise who cares? call it lazy, call it cheap, call it what you want. most of the installs i do i run them on opposite sides of the car if its convienient, but many times 1 side of the car will be factory wire free for the most part and usually its the passenger side. so why not? if i get engine noise try another route, no big deal, my point was simple that the leading cause of alternator whine is not 100% caused because you ran power and preamp too close to each other.

i realise your trying to help but agruing with me and trying to prove me wrong when clearly you dont have the qualifications to back up your theroy i think is less than helpfull. if you want to help how about we keep this on a friendly note and stick to facts that we can prove or have the background to back up. 90% of the people reading this thread stopped reading it about 6 posts back.

your neener neener post certainly contributed nothing usefull and although i think your intent was to be funny was pointless.

ill im trying to do is make some corrections on some missinformation you communicated. most of which i think you agreed with, so why all this back and forth bickering? it accomplishes nothing, proves nothing, and other than ego's that got hurt i see no point to the defensive words.
if you want to help either offer advice you can prove with facts rather than trying to make it sound to the uninformed like you know more than you do.
ive been in caraudio for 16 years and i know for a fact for every good installer that actually knows electronics theroy and can back it up with a degree, there are at least 1000 more installers out there that would like the laws of physics to change to make them right without the education to prove it otherwise.

so i ask which are you? if your not the first type than how about we stick to subject matter that is a little more basic and less likely to get someone with more experience to challenge you on it, shall we?

P.S. im through with this thread, so get your last words in if you must, im moving on, i made my point. if you have the nerve to reply with another snide remark it only makes you look worse. i dont need to proove anything to anyone here. im already reguarded as someone that many people have already asked for my advise and assistance because they know i know what im talking about. with 20 some odd posts count here you havnt earned your wings yet.

meteorman

elduderino

God, I love the Internet.

Anyway, anybody wanna talk about their engine noise problems?

elduderino

Oh, btw, now that it's NOT a point of contention:

Started in the 12V business in 1986. Sales, installation, management, have owned my own store. Served as head of technical support at large 12V equipment manufacturer for many years. Lucky enough to have been awarded a U.S. patent for innovations in security system design. Served as head of a car audio division, and as such managed the development of two speaker lines and one amplifier line. Managed the development (at another firm) of the first interface between the OBD-II onboard data bus and an in-car PC USB bus, and the development of a number of in-car computing software applications. Also managed the development of a wireless e-mail device that allowed the AutoPC to receive and send emails (boy, that AutoPC was a big seller - that product was never launched). Served on the Certification and Education committees of the CEA, and helped write the Installer Certification handbook and the Master's level Certification exam (The section on digital to analog conversion is mine). Served as the Chair of the Education committee. Wrote several product reviews for Car Audio and Electronics over the years, and several technical articles for Installation News/Mobile Electronics Retailer. Designed and installed the systems in about half a dozen CES demo cars (dating back to the Yamaha YDSP-1 surround processor, the first digital signal processor for the car.) I now own my own consulting firm and have been helping 12V companies with their product development since 2000. I am currently helping test the first rear-seat video entertainment system with a built-in video game system.

And none of that means anything - I could still have my head up my ass. Y'all will have to decide for yourselves. Sorry this thread went sideways.

jiggaman

i have very slight engine noise. i didn't install it though so it's anybody's guess where the problem lies i can only hear the engine noise when the volume is at like 5 or less and it's hardly noticeable. next time i bring my car back to get the rear door speakers replaced i'm gonna have them try to check it out though. it's not bothersome enough to bring it back to the installers.

e_lectro

Welcome to acura-tsx folks, where else can you get 3 electrical-engineering/audio-installing/carbuffs making noise over noise?


Who was it that said this was a geeks car? lol

slo007

You are all wrong! The Industrial Engineer is always right.

I can't wait to get rid of the noise in my audio system. I'll probably have to re-do the whole car as the audio store goofed everything.

davestar

sigh... as an EE, i can assure you that my coworkers and i would refer to a rectified AC signal + DC offset as containing an AC signal. yeah, it's not technically correct, but for the sake of brevity - IT'S AC!!! semantics arguments are always fun though... right?

anyway, it's good to see some posts that aren't strictly about iPods and NAV systems!

elduderino

(Electrical geek warning! If you don't care about theoretical wanking, do not waste your time reading this drivel)

After drawing it out (I drew it and made a PDF but figuring out how to post it here is kicking my ass) I think he was trying to say that with one alternator revolution, the alternator output is a full sine wave at a peak of 14.4V. One peak is positive and one is negative. (Ignore the periods.)

....... *..............14.4V +
......* *
.....*....*.....*...0 V
.............*..*
...............*.....14.4 V-

After you full-wave rectify it you have two peaks that are positive.


........*........*.......14.4 V
......* *....*...*
....*.......*........*...0 V

The background voltage (due to the battery) is 13.8 (that's what lead-acid "12V" batteries want to rest at). So for each alternator revolution, you have two 0.6V ripples above the 13.8V battery voltage, and I think he is saying that that is where the noise comes from, from these 0.6V (+) ripples in the 13.8 battery voltage.


..........*.........*..........14.4+
.*****..*****..***** 13.8+


And I think he's correct, partially, if this is what he meant (I'm not sure but I think this is what he was driving at). A couple of observations, though:

1) This assumes that full-wave rectification is happening. I am told by some experienced folks that not all car alternators use full-wave rectification, some use half-wave rectification (cheaper to make - only one big honkin' diode), and they just don't use the lower half of the waveform. This means they are less efficient, but it also means they are noiser. Why? Because the battery takes some time to dissipate, or lose, its charge from 13.8V up to 14.4V. Let me explain - when you have full-wave rectification, you have two bumps in the voltage for every alternator revolution. With full-wave rectification, the battery actually smooths out the voltage between the peaks (which is part of why toasted batteries allow more noise) - it does this because it takes a few fractions of a second to "lose" that 14.4 V charge. With half-wave rectification, you only get 1 bump for each alternator revolution, and that's half the frequency, with twice as long between peaks, and the battery dissipates farther back towards 13.8V during that time, and the noise peaks are therefor higher in amplitude against the background DC voltage from the battery.

Of course, we have totally ignored the AC emitted by the alternator winding onto the wires in the engine compartment, like the battery cables.

See, I told you it was theoretical wanking.

davestar

from what i read, the typical car alternator is a 3-phase AC source. when full-wave rectified, there is very little voltage ripple on the output. couldn't tell you if that ripple is enough to induce significant noise in an audio system though...

e_lectro

ahem, http://www.carsound.com/UBB/ultimate...c;f=1;t=022690

elduderino

Sigh... Clark and Navone are right a lot of the time (just ask them, they'll tell you : ).

When my experience contradicts someone else's theoretical statement, I can either decide that my observations are wrong (or incomplete/invalid) or that my observations are correct and valid and the theory is possibly not all-encompassing.

I have experiences moving RCA cables and power wires and eliminating noise. Is it theoretically possible that the noise in question wasn't being radiated by the power wire itself, but by something else? On a case-by-case basis, yes. In the aggregate, I really don't think so.

The theoretical explanation is a model for how reality works. The map is not the territory. There is often something left out of the theoretical model. If I had personal experiences with sea-dragons, then I'd stick up for them, but I don't have any...

One of the things I have to do in my line of work is go back-and-forth with electrical engineers who think their model is complete and accurate when it may not be an accurate representation of reality (or it may leave out significant factors). Here's how an engineer finally decides they made a mistake and left something out of their calculations:

"No, you're wrong.

No, you're wrong.

No, you're wrong.

... Oh, well, that makes sense, because <blah blah blah>" (As if THEY thought of it.)

davestar

zing! now you're going after us EEs!!!?!?

;-)

slo007

Where's the pop corn anim gif?