# series or parrallel?



## fishin' musician (Jun 19, 2008)

I am in the process of building a new speaker cabinet with a pair of 10" alnico speakers. The amp I will be using with this cabinet has a multi-tap output transformer and will accept loads of 4, 8 or 16 ohms. Since the speakers are 8 ohm I can wire the cabinet in parrallel for a 4 ohm load or in series for a 16 ohm load. My question is this, is there any advantage (either sonic or otherwise) for wiring the cabinet one way or the other?


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## greco (Jul 15, 2007)

Interesting question. 

I'm going to put my money (all $0.19 of it) on the fact that there will be no difference.

Cheers

Dave


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## nonreverb (Sep 19, 2006)

fishin' musician said:


> I am in the process of building a new speaker cabinet with a pair of 10" alnico speakers. The amp I will be using with this cabinet has a multi-tap output transformer and will accept loads of 4, 8 or 16 ohms. Since the speakers are 8 ohm I can wire the cabinet in parrallel for a 4 ohm load or in series for a 16 ohm load. My question is this, is there any advantage (either sonic or otherwise) for wiring the cabinet one way or the other?


The advantage to 16 ohm is if you have a loooong speaker wire the power loss is lessened due to the higher impedance. ie. if you have a 2ohm impedance on a 4ohm system, that's 50% more impedance and therefore a significant loss of power. However, a 2ohm increase in impedance on a 16 ohm impedance is only 12.5 % so the effective loss is much smaller. Apart from that, the differences are nil as you're matching the output impedance of the transformer
to the speaker and therefore power transfer is the same.


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## Adicted to Tubes (Mar 5, 2006)

You need to try and see.Paralleled speakers dampen out transients and often do sound better.There is a difference.


www.claramps.com


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## Wild Bill (May 3, 2006)

Adicted to Tubes said:


> You need to try and see.Paralleled speakers dampen out transients and often do sound better.There is a difference.


I've heard this before but never seen any explanation for it. How would it dampen transients? Electrically, the power is split the same way. Acoustically, if the speakers are always in phase wouldn't that be the cause of any cancellation, regardless of how the speakers are wired?

I hope I'm not too old to learn something new!:smile:

:food-smiley-004:


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## mhammer (Nov 30, 2007)

There is the electronic side, and there is the electro-mechanical side to this. As an electric "motor" that is moving a physical load of fixed mass (the speaker cone), speakers do not respond in a linear manner to the current passed through the coil. At low output current, the motor struggles with the physical load, but at higher output current ("cruising speed"), the "bodies in motion..." principle starts to help out. It makes sense to me that splitting up the current between multiple drivers could result in each driver adopting the oh-geez-do-I-*have*-to-get-up-off-the-chair? response to transients.

At the same time, though, I would expect it to be a function of how much power one is pumping into the speakers. In other words, assuming there IS some transient damping, it may simply be a function of moving the point where normal transient damping stops happening to a higher output level. I.E., if transient damping normally happens with a series load when output is lower than 1.8W, transient damping will occur with a parallel load up to the point where output is 2.9W (I'm pulling those numbers out of my, um, "storage facility").

That is NOT an authoritative opinion by any means. It is mere speculation. I offer it up simply as a way of trying to reconcile what some folks believe they have observed, and what other folks don't think they have ever observed. They might both be right, and phenomenon in question will occur in some contexts but not in others.


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## mhammer (Nov 30, 2007)

nonreverb said:


> The advantage to 16 ohm is if you have a loooong speaker wire as the power loss is lessened due to the higher impedance. ie. if you have a 2ohm impedance on a 4ohm system, that's 50% more impedance and therefore a significant loss of power. However, a 2ohm increase in impedance on a 16 ohm impedance is only 12.5 % so the effective loss is much smaller. Apart from that, the differences are nil as you're matching the output impedance of the transformer to the speaker and therefore power transfer is the same.


That is an excellent observation.:bow:


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## Wild Bill (May 3, 2006)

mhammer said:


> There is the electronic side, and there is the electro-mechanical side to this. As an electric "motor" that is moving a physical load of fixed mass (the speaker cone), speakers do not respond in a linear manner to the current passed through the coil. At low output current, the motor struggles with the physical load, but at higher output current ("cruising speed"), the "bodies in motion..." principle starts to help out. It makes sense to me that splitting up the current between multiple drivers could result in each driver adopting the oh-geez-do-I-*have*-to-get-up-off-the-chair? response to transients.
> 
> At the same time, though, I would expect it to be a function of how much power one is pumping into the speakers. In other words, assuming there IS some transient damping, it may simply be a function of moving the point where normal transient damping stops happening to a higher output level. I.E., if transient damping normally happens with a series load when output is lower than 1.8W, transient damping will occur with a parallel load up to the point where output is 2.9W (I'm pulling those numbers out of my, um, "storage facility").


But Mark, in either case the current through each speaker is exactly the same, series or parallel. I would think that with a voice coil's magnetic field current would be more important than overall power. I could be wrong.

However, we still haven't established if there's actually any transient damping anyway, or even any transients, for that matter!

:food-smiley-004:


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## greco (Jul 15, 2007)

Just to relate back to the original poster's question...are we talkin "mice nuts" * (* quote Wild Bill) sonic or otherwise advantage of wiring the speakers in series vs parallel.... ...or "elephant nuts" OR is that yet to be decided ? (meant in jest...not intended to offend anyone)

Very interesting discussion (.....to the extent I can keep up with it !!)

Cheers

Dave


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## mhammer (Nov 30, 2007)

Wild Bill said:


> But Mark, in either case the current through each speaker is exactly the same, series or parallel. I would think that with a voice coil's magnetic field current would be more important than overall power. I could be wrong.
> 
> However, we still haven't established if there's actually any transient damping anyway, or even any transients, for that matter!
> 
> :food-smiley-004:


Two good points. My own bias is that whenever one hears claims of some ephemeral effect that isn't immediately something that everybody says "Oh yeah, *I've* heard that.", it isn't _necessarily_ poppycock. It can often be a real phenomenon observed under conditions that not everyone spontaneously runs into, or pays attention to.

What I'm not sure has been brought up is whether the claim of transient damping is observed when the load is reconfigured *without* a change in output transformer setting, or with a change.


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## Guest (Feb 19, 2009)

Dave: I'm going with "mice nuts" here. All of the claims I've read concerning differences re parallel v. serial have been after someone rewires a cab. That's too uncontrolled a change and a measurement to convince me it's making any noticeable difference to anyone else other than the guy doing the work.

After I tweak something to death my litmus test is my wife. She'll tell me straight out if I just spent 5 hours _convincing_ myself I was making a difference in sound versus 5 hours actually making a difference in the sound of what I'm tweaking.


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## greco (Jul 15, 2007)

iaresee said:


> Dave: I'm going with "mice nuts" here. All of the claims I've read concerning differences re parallel v. serial have been after someone rewires a cab. That's too uncontrolled a change and a measurement to convince me it's making any noticeable difference to anyone else other than the guy doing the work.
> 
> After I tweak something to death my litmus test is my wife. She'll tell me straight out if I just spent 5 hours _convincing_ myself I was making a difference in sound versus 5 hours actually making a difference in the sound of what I'm tweaking.


So...*fishin musician*....in the end, you might just have to ask your wife to decide for you....simple kksjur

Dave


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## fishin' musician (Jun 19, 2008)

greco said:


> So...*fishin musician*....in the end, you might just have to ask your wife to decide for you....simple kksjur
> 
> Dave


Oh no...whenever I play guitar for my wife she keeps asking if I know how to play "that nice James Blunt song"


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## fishin' musician (Jun 19, 2008)

In the end I've decided to wire in parrallel since all of my other cabinets are 4 ohm. That way, if I decide to use an extension cab I can use a series wired y-connector and plug into my 8 ohm output.

Dwayne


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## Guest (Feb 19, 2009)

greco said:


> So...*fishin musician*....in the end, you might just have to ask your wife to decide for you....simple kksjur


Don't all us married guys just do that by default? For everything? :smile:


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## gtrguy (Jul 6, 2006)

I'd say that you should go parallel. That way should one speaker blow and go open the other will still present a load to the amp... better than having them in series and presenting no load to the amp...

gtrguy


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## Guest (Feb 19, 2009)

gtrguy said:


> I'd say that you should go parallel. That way should one speaker blow and go open the other will still present a load to the amp... better than having them in series and presenting no load to the amp...


Hmm...is that how it works? My intuition says a speaker, melting down, starts to look like an infinitely large impedance to the amp, not a wire. It's a guess though. I'm not sure what an inductor decays into as it melts. Although, if your speaker is melting you've got bigger problems than the load seen by your amp.

If you're just talking about a speaker cone ripping, I don't think that'll change the impedance much, if at all, seen by the amp.


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## greco (Jul 15, 2007)

This whole thread has become so much more complicated than I originally expected it to be. Just an observation...

Cheers

Dave


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## hollowbody (Jan 15, 2008)

iaresee said:


> Don't all us married guys just do that by default? For everything? :smile:


Haha, maybe. But my partner plays guitar, bass and mandolin and has no qualms about voicing her opinion on how my tone sounds (it's usually crap in her opinion). But then again, I always want to tinker with her Strat when she's not looking because I think I can "improve" the way it sounds and plays


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## Guest (Feb 19, 2009)

hollowbody said:


> But then again, I always want to tinker with her Strat when she's not looking


Hehe. I love tinkering with their gear when they're not expecting it.


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## Wild Bill (May 3, 2006)

iaresee said:


> Dave: I'm going with "mice nuts" here. All of the claims I've read concerning differences re parallel v. serial have been after someone rewires a cab. That's too uncontrolled a change and a measurement to convince me it's making any noticeable difference to anyone else other than the guy doing the work.
> 
> After I tweak something to death my litmus test is my wife. She'll tell me straight out if I just spent 5 hours _convincing_ myself I was making a difference in sound versus 5 hours actually making a difference in the sound of what I'm tweaking.


Exactly! There's too much psychology in many of these observations.

Me, if it's not a blindfold test I just take it as unproven. In fact, since I've had a couple of people lie and claim they underwent a blindfold test when in fact they didn't I'm now at the point where I want to do the test myself, or at least know the tester personally!

It has nothing to do with honesty. A person can be truly sincere and still be dead wrong.

:food-smiley-004:


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## Ripper (Jul 1, 2006)

Wild Bill said:


> Exactly! There's too much psychology in many of these observations.
> 
> Me, if it's not a blindfold test I just take it as unproven. In fact, since I've had a couple of people lie and claim they underwent a blindfold test when in fact they didn't I'm now at the point where I want to do the test myself, or at least know the tester personally!
> 
> ...


I did this test a couple of years ago with three fellow musicians as guinea pigs. I had a 4x12, wire it up parallel, played through it for them, then wired it series, played through it for them. they couldn't tell the difference. One of the guys has an okay ear but the other two have really good ears and they couldn't tell the difference. I vote "mice nuts" on this one.


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## nonreverb (Sep 19, 2006)

Wild Bill said:


> Exactly! There's too much psychology in many of these observations.
> 
> Me, if it's not a blindfold test I just take it as unproven. In fact, since I've had a couple of people lie and claim they underwent a blindfold test when in fact they didn't I'm now at the point where I want to do the test myself, or at least know the tester personally!
> 
> ...


I feel I must agree Bill...no offence to those who believe differently. Who knows, maybe in the audiophile world there may be some validity to the idea but in the rock 'n roll guitar amp world I don't think so.:smile:


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## nonreverb (Sep 19, 2006)

gtrguy said:


> I'd say that you should go parallel. That way should one speaker blow and go open the other will still present a load to the amp... better than having them in series and presenting no load to the amp...
> 
> gtrguy


I agree....to a point. Here's a little scenario for you: Suppose you have a 2 speaker cab with two 30 watt speakers in it. You are driving it with a 40 watt RMS amp dialed way up. For some inexplicable reason..."pop" one speaker goes open.
In series the cab stops working. The player immediately stops and knows something is drastically wrong. In parallel the cab keeps chuggin' along on one speaker.....BOOM... now you have two blown speakers. Even though the impedance will change the output wattage somwhat, the fact that the only remaining speaker is 30 watts means that there's a good chance it will blow if the full output current is applied to it. Remember failures like this almost always happen when the amp is full tilt. Of course with the typical Marshall cab which is series/parallel the problem isn't as critical. However, there is a definite advantage to series wiring in certain circumstances. I should know...I smoked two Jensen P12N's that way back in my crazy days.


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## Adicted to Tubes (Mar 5, 2006)

I have wired a pair of 10" Eminence Ramrods in parallel and series in an 18 watt combo.I did hear a difference in the sound.But.....I attribute the difference to the different winding being used on the output transformer rather than the speaker wiring method.
The biggest difference in sounds I have heard is when the speakers are firing forward or backwards. i.e. celestions vs Jensens or american speakers.
When you wire a celestion into a cab with a Jensen,they need to be wired in series or the sound is awful!We proved this with a Victoria double Deluxe just last week.
The Victoria was water damaged unit from Long & Mcquade in Calgary.One Jensen was ruined so the owner replaced it with a Celestion.They are normally wired in parallel so he wired the Celestion in parallel.The amp sounded absolutely crappy,so he thought it was something with the tubes.After replacing tubes till he was blue in the face,we checked the speakers with a 9v battery to see which way they fired.The celestion fired oposite to the Jensen,so we wired them in series and the amp sounds perfect now.The DC resistance measured 4 ohms with the two mis-matched 8 ohm speakers wired in series.
Now I know this phenomena does not apply to same-make speakers,but what was happening here?


www.claramps.com


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## Guest (Feb 21, 2009)

Adicted to Tubes said:


> I have wired a pair of 10" Eminence Ramrods in parallel and series in an 18 watt combo.I did hear a difference in the sound.But.....I attribute the difference to the different winding being used on the output transformer rather than the speaker wiring method.


Speaks volumes to my "lots of things changing" comment.



> The biggest difference in sounds I have heard is when the speakers are firing forward or backwards. i.e. celestions vs Jensens or american speakers.
> When you wire a celestion into a cab with a Jensen,they need to be wired in series or the sound is awful!We proved this with a Victoria double Deluxe just last week.
> The Victoria was water damaged unit from Long & Mcquade in Calgary.One Jensen was ruined so the owner replaced it with a Celestion.They are normally wired in parallel so he wired the Celestion in parallel.The amp sounded absolutely crappy,so he thought it was something with the tubes.After replacing tubes till he was blue in the face,we checked the speakers with a 9v battery to see which way they fired.The celestion fired oposite to the Jensen,so we wired them in series and the amp sounds perfect now.The DC resistance measured 4 ohms with the two mis-matched 8 ohm speakers wired in series.
> Now I know this phenomena does not apply to same-make speakers,but what was happening here?


Sounds like plain old phase cancellation happening. The only reason you're not experiencing it when you use two speakers from the same manufacturer is because they label they + and - terminals on the speaker coil the same way. The Jensen likely called + opposite what the Celestion called + so they were out of phase.


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## Wild Bill (May 3, 2006)

iaresee said:


> Sounds like plain old phase cancellation happening. The only reason you're not experiencing it when you use two speakers from the same manufacturer is because they label they + and - terminals on the speaker coil the same way. The Jensen likely called + opposite what the Celestion called + so they were out of phase.


Yep! Diddleysquat to do with series or parallel! Phasing so that the cones move in unison is a completely different issue.

In fact, you had a 50/50 chance of ending up out of phase and having crappy sound in your SERIES wiring! It just depended on which two terminals on one of the speakers got flipped.

:food-smiley-004:


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## fishin' musician (Jun 19, 2008)

To see the end result of the amp that sparked the original series/parrallel question check out the Laney LC15R rebuilt post in the Amp Tech Section.

-Dwayne


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## User_X (Feb 1, 2008)

Keep in mind that speakers are complex, reactive, loads and such things as the inductive component appearing in series vs parallel may affect the overall impedance picture presented to the amp i.e. impedance is frequency dependent as are inductors, so the load curve may change.

I can't provide the electrical theory, in total, but am willing to accept that there _may_ be hearable differences series vs parallel.


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## Wild Bill (May 3, 2006)

User_X said:


> Keep in mind that speakers are complex, reactive, loads and such things as the inductive component appearing in series vs parallel may affect the overall impedance picture presented to the amp i.e. impedance is frequency dependent as are inductors, so the load curve may change.
> 
> I can't provide the electrical theory, in total, but am willing to accept that there _may_ be hearable differences series vs parallel.


I too would be willing to accept the idea! However, I DO know a lot of electronics theory and before I can accept the idea I would need a damn good technical explanation OR a consistent blindfold test that proves it!

The inductance will change, giving a different reactance value. Reactance is like 'AC resistance' and indeed is frequency dependent. DC resistance plus AC reactance is what we call impedance.

However, the impedance of a voice coil winding is "mice nuts" at audio frequencies! What's more, even if you had a NASA lab full of equipment you might be able to measure it but that doesn't mean such a tiny value makes an audible difference to the human ear.

Claims about inductance with parts such as speakers and resistors are really misunderstandings of this simple truth about reactance values vs. frequency. Sells a lot of carbon composition resistors to audiophiles, though!

When you don't know about something then anything seems equally possible. Actually, the less you know the easier it can be to make something seem logical! You end up dealing only in those facts that support your argument and you are unaware of any that attack it.

My advice to those who wish answers to such questions is always the same. You can either run a proper experiment to test your premise or, you can read some books!

There really aren't any other ways.

:food-smiley-004:


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## Rugburn (Jan 14, 2009)

Wild Bill, I have an excerpt from a book called " Using The Carbon Comp Resistor For Magic Mojo" by R.G. Keen. "Carbon comps have excess noise, high drift, high pulse power and high variability. They also have a high voltage coefficient of resistance. That means the resistance actually varies with the voltage across the resistor....We have resistor distortion....That's what carbon comp resistor mojo really is-- the resistors are distorting, but in a way our ears like". Do you think this is valid in some of the older/vintage circuits? Or do you feel it's best to use metal film resistors for the most accurate performance? Just wondering as I haven't had the benefit of having installed and listened to the difference in high voltage amps new and old, as I know you have. 

Thanks Shawn :wave:


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## Wild Bill (May 3, 2006)

Rugburn said:


> Wild Bill, I have an excerpt from a book called " Using The Carbon Comp Resistor For Magic Mojo" by R.G. Keen. "Carbon comps have excess noise, high drift, high pulse power and high variability. They also have a high voltage coefficient of resistance. That means the resistance actually varies with the voltage across the resistor....We have resistor distortion....That's what carbon comp resistor mojo really is-- the resistors are distorting, but in a way our ears like". Do you think this is valid in some of the older/vintage circuits? Or do you feel it's best to use metal film resistors for the most accurate performance? Just wondering as I haven't had the benefit of having installed and listened to the difference in high voltage amps new and old, as I know you have.
> 
> Thanks Shawn :wave:


Ah Shawn, read the WHOLE thing! Mr. Keen is amazing and a true genius. He has written about carbon comps at other times as well. If you go to his site at http://www.geofex.com and poke around you'll read more about carbon comps.

This slight change in resistance with voltage is the ONLY thing he could find about the old resistors that might affect the sound! What's more, in a typical guitar amp there are very few places where that can happen. All the preamp tubes are run in class A. There is NO change in the plate voltage! You have to have some real current flow happening to cause a noticeable voltage drop or change and the only area where there is even 'mice nuts' worth of that happening is with the plate resistors of the phase inverter, or PI, driver to the output tubes. Keen has said that he's not sure that while the effect at that point might be happening he's also not sure if anybody has ears good enough to hear it! Certainly, you'd also have to be talking a LOUD setting on the amp!

To my mind, we're talking about something that is non-existent to perhaps measurable but unnoticeable. Meanwhile, carbon comps still can make a ton of hiss and spit in your amp!

Doesn't seem like a good trade to me.

:food-smiley-004:


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## User_X (Feb 1, 2008)

Wild Bill said:


> However, the impedance of a voice coil winding is "mice nuts" at audio frequencies! What's more, even if you had a NASA lab full of equipment you might be able to measure it but that doesn't mean such a tiny value makes an audible difference to the human ear.
> 
> :food-smiley-004:


Check out this:
http://en.wikipedia.org/wiki/Electrical_characteristics_of_dynamic_loudspeakers
Note the swings in impedance presented to an amp. (lots of other graphs available)
I can't verify that a series load presents differently to a parallel one, but how could it not? Can we hear it? Beats me, but I think the effect _might_ be rated in peanuts.:smile:


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## Wild Bill (May 3, 2006)

User_X said:


> Check out this:
> http://en.wikipedia.org/wiki/Electrical_characteristics_of_dynamic_loudspeakers
> Note the swings in impedance presented to an amp. (lots of other graphs available)
> I can't verify that a series load presents differently to a parallel one, but how could it not? Can we hear it? Beats me, but I think the effect _might_ be rated in peanuts.


Yes, there are swings in impedance. The important point is that the values involved are trivial. Also, the human ear doesn't hear impedance. It hears waves of moving air.

Any differences in impedance will affect the amplifier circuit. Output devices are constantly seeing changes in loudspeaker impedance as they amplify a signal. The impedance actually changes over a wide range. For practical purposes, the amplifier doesn't notice! Especially if the circuit uses a lot of negative feedback, which almost all such amplifiers do.

The most important thing to understand is not whether or not you can name a factor. You have to define if the AMOUNT is trivial or significant!

This is where so much of the mojo about electronics and sound comes from. People who are not that technical hear about something and think that naming it is enough.

Consider something like stray capacitance. You might notice that a certain shielded cable is advertised as having a lower capacitance than another and you are expected to believe that this makes it better than another cable for your guitar. In theory, this is quite true. There is a capacitance between the inner wire and the overall shield. A capacitor will have a reactance value at a given frequency. So this capacitance along a shielded wire will tend to bypass, or short out, some signal. Since reactance is frequency dependent this capacitive reactance will be lower for a high frequency than a lower one. So you will lose some highs in a cheaper cable.

Now if you're an advertising suit that's enough but if you're a tech it might be BS! First off, how MUCH difference in capacitance is there between the two cables? If one has a figure of 10 picofarads per foot and the other has 11, that 1 pf difference is mice nuts difference at audio frequencies. You'd have to be generating a signal at so high a frequency you could talk to the space station before it would matter!

Also, the length of the cable matters. In a 10 foot cable that 'per foot' number is multiplied 10 times. That's still not a big deal with audio. However, if you ran a cheap cable with a high capacitance per foot value around your studio, where the lengths could add up to 50 or 100 feet then you might lose a noticeable amount of highs.

Of course, if you pushed the treble knob up a notch or two that would probably take care of it!

I blame the media and today's education system for this lower baseline in scientific thinking in society. Since I'm an old fart this is only traditional, of course!:smile: Still, I don't think I'm pulling this out of my butt! One of my daughters had a grade 5 science teacher who told them that it was cold on top of mountains 'cuz there's snow there!:smile:

Like dioxins in Great Lake fish, for another example. Dioxin is a poison and yes, it has been found in such fish. Yet no one really knows how much fish you'd have to eat before it could hurt you. So the government just sets really low limits to be safe. Yet there may be a lot of really old native Canadians who have eaten those fish all their lives and are still going strong.

A teaspoon of salt will kill a baby if it were to swallow it all at once. Is salt a poison and should be totally avoided? If we were dumb enough to do it we'd kill ourselves!

Oh well, I've ranted long enough!:smile: I'm sure you see my point. It's the details that matter the most, especially with technical matters.

As Gilda Radner used to say "It's always something!"

:food-smiley-004:


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