The ABC of speakers - the least an audiophile must know. A series of posts to start conversations about the principles of speaker audiophilia.

siddharthdas

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I am newly active here. After doing a brief survey, I thought I might create short series of posts around some issues that are widely discussed but seldom addressed from the pov of the learner. I am what you might call an advanced learner. So bear with me for stating the obvious. I am curious to examine what a very fundamental "shared" understanding of audiophile experiences is about. I am like all engineers, objective. The people who design and build speakers most definitely are, and those that evaluate them such as reviewers seem to have scant regard for most engineering.

A great example of that are cables. The "best" cables are those that do not exist i.e. directly couple components - short cables with low R/C/L values are the best, and yet there's mind-boggling amount of material on cables, including cables that cost thousand of $$$ per meter.

I am an engineer, so I'll focus a creating a platform for the known principles of engineering that goes in a speaker and therefore what makes for a great speaker. The one thing to remember is - tradeoffs. Often achieving one thing means sacrificing another. So great design, is often about the right balance - one set of choices are likely to produce different results than another - and neither subjectively superior to the other. Just meeting a different set of objectives.

Back to our topic though. So I'll write about the following principles in brief - each in a different post, to enable separate conversations on each. Let me state at the outset, that none of this is new or inaccessible elsewhere (for example, linkwitzlab.com, of which I am a big big fan). My effort rather, will be to lay things out in simple terms accessible to all. The topics -

Dispersion.
Dynamic Range.
Distortion.
Drivers.
DSP/Crossover.
Dipoles vs Box Speakers.
and finally I cannot find a word starting with D - Cables!!!
 
A great example of that are cables. The "best" cables are those that do not exist i.e. directly couple components - short cables with low R/C/L values are the best, and yet there's mind-boggling amount of material on cables, including cables that cost thousand of $$$ per meter.
The text highlighted in bold is the truth, but even when somone has done engineering or understands physics, I find many in this forum believe "Music works in mysterious ways". No amount of scientific principle can convince them and they will continue to promote things like esoteric power cables, ethernet cables and believe it or not "break-in" period for cables. The best thing to do is to smile and move on because mostly they are falling prey to psycho-acoustics.

But it is good that you have started this thread. I for one will be a keen follower.
 
Well, the wisdom of the masses. It's interesting - people look for the best doctor they can find to treat their illness, but are okay with a gangster running their state. People see no contradiction in the that. I think we probably fail to understand something foundational about how the human mind works.
 
Hi, respectfully : my two cents :

Have FUN in your thread, post away, but IMHO / IME :

The ABC of speakers , after 78 years of hearing / owning high end speakers ( from birth , first was Dad's field coil ALTEC 604 coaxial 12-1944 ) is to buy ALTEC and pair it with a truly great zero NFB tube amp.

Then you are DONE ...... with both amplifiers - and speakers.

Great tube amp must be configured in two stages, directly coupled . Very EXCITING - to hear this.

Best wishes,

Jeff Medwin
 
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Hi, respectfully : my two cents :

Have FUN in your thread, post away, but IMHO / IME :

The ABC of speakers , after 78 years of hearing / owning high end speakers ( from birth , first was Dad's field coil ALTEC 604 coaxial 12-1944 ) is to buy ALTEC and pair it with a truly great zero NFB tube amp.

Then you are DONE ...... with both amplifiers - and speakers.

Great tube amp must be configured in two stages, directly coupled . Very EXCITING - to hear this.

Best wishes,

Jeff Medwin
How wonderful would it be to get to hear that. Alas, from here in Bangalore, that's a long shot!
 
Alongwith low RCL values, the cable must also be well shielded. If there is no/poor shielding, it will pick up all sorts of stray emi which will ruin the final output.
 
Speaker cable is a transmission line. If you consider R/L/C then consider characteristic impedance too at the termination.
 
How wonderful would it be to get to hear that. Alas, from here in Bangalore, that's a long shot!

First, I am very-very pleasantly surprised at your response to my post. You took me at face value - to be telling the truth, at least - as far as I see it. Your open mind was such a breath of fresh air !! Appreciated ...... !!

I have an important loudspeaker question for any older experienced Indian HFV FM :

Were Altec Lansing VOTTs ( Voice of the Theater ) speakers used in India's movie theaters ??

( Often not seen - several enclosures / speakers positioned right behind the motion picture screen. ) This would have been between about 1947 - to maybe 1990, as was the prevalent practice in the USA ??


If so, Indian HFV FMs over 60 in age may have grown up, listening to one half of the answer I proposed, an Altec Lansing VOTT A7-8 at the movies !!

For myself, as a kid, going to the movies was always a treat - since it always sounded wonderful, mid-row seating on back. Diction was so clear.

Realize this, it HAD to sound great, because people were spending their money, to BOTH see and hear a movie. They will not return to that specific movie theater venue, and spend more money, unless they had an outstanding sensory experience, which was well-worth what they had spent.

The other half of the equation, ( use of a truly-great-sounding tube amp ), is a whole other topic, unto itself.

Only a handful of people I know of are thought-process-qualified, to develop same. It takes ( IME ) much-much more than having any technical degree, such as being a very respectable mathematician, E.E. or a PhD !!

I have been working on tube amplifiers for four decades, since 1982, with my first all triode zero NFB P-P-P 6B4G amp build. One can view a 1982 first " all-out " attempt, ( photo of one channel below ) . B+ in 1982 was double actively regulated. In 2022 we do it SE , DC, but often-times today, the tube amp's B+ is passively quadruple filtered. Schematic, ......... search term on HFV ........." Triple 6005 ".

SNIP TMA 3 chassis.JPG

Nice to meet you. Have fun with your first thread. Many FMs will likely really enjoy it !!!

Jeff Medwin
 
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Alongwith low RCL values, the cable must also be well shielded. If there is no/poor shielding, it will pick up all sorts of stray emi which will ruin the final output.
Well absolutely!!!

Speaker cable is a transmission line. If you consider R/L/C then consider characteristic impedance too at the termination.
That's true too!
 
You @siddharthdas can make much more sense of this article than me. This article by Ben Duncan was first published in 1995 and explains that cables, crossovers and speakers are all energy storing devices (by virtue of capacitance and inductance). So let's say when we are feeding a signal of 1 Khz for example and when the signal is suddenly stopped, the voltage cannot become zero. However solidstate devices by virtue of using negative feedback, this shouldn't be a problem.
Over the past decade, ideas have changed regarding how loudspeaker cables should be best designed in order to accurately transfer audio signals. In a 1991 AES paper on cable (footnote 4), down-to-earth US audio consultant Fred Davis attacked cable makers' hypotheses that factors of undeniable importance at radio frequencies (notably, the characteristic impedance) were of relevance at audio frequencies given the length of any practical speaker cable runs.
-- Fred E. Davis, "Effects of Cable, Loudspeaker and Amplifier Interactions," Journal of the Audio Engineering Society, Vol.39 No.6, June 1991.

Caveats
Even without advertising hype and misinformation, determining the "best" speaker cable for a given real-world situation is a complex issue. If your power amplifier turns into an RF oscillator because it can't handle high or even modest capacitance (and some otherwise reputable designs can easily fail under these conditions), you'd likely find the sonics better with a lesser (but less-capacitative) cable. If no one bothers to check for RF, using suitable equipment (at least a 35MHz 'scope), entirely wrong sonic decisions can be made. If RF occurs, then to use the low-inductance cable that speakers need, you should consider a) having the amplifier retired or sold; b) having the amplifier re-engineered for proper stability, using parts costing as little as $20; or c), less drastic than the first two options, moving the amplifier(s) next to (or much nearer to) the loudspeakers, so the cable capacitance (always a product of length) is slashed.

Another pitfall is with tube amplifiers, and transistor amplifiers with zero or low overall negative feedback. Their damping can be so poor (far worse than the situation seen in figs.12–19) that the cable's damping differences documented here may be swamped, again leading to a different optimum.
 
"Speaker cable is a transmission line. If you consider R/L/C then consider characteristic impedance too at the termination."
"That's true too!"

Respectfully I disagree.

A Hi Fi Speaker Cable does not behave as a transmission line.

It also does not have a Characteristic impedance.

Transmission lines are often not well understood.

Unfortunately we would be digressing too much from the topic of this thread, to address it here..... Maybe another time, another place.....:)
 
"Speaker cable is a transmission line. If you consider R/L/C then consider characteristic impedance too at the termination."
"That's true too!"

Respectfully I disagree.

A Hi Fi Speaker Cable does not behave as a transmission line.

It also does not have a Characteristic impedance.

Transmission lines are often not well understood.

Unfortunately we would be digressing too much from the topic of this thread, to address it here..... Maybe another time, another place.....:)
Why do you think CI won't apply to a speaker cable.? Curious to know. We always talk about damping factor as it's easy to phantom. If a cable has a L & C then it will definitely have a CI which is a sqrt(L/C). How much they IMPACT SQ and sound staging is a completely different topic for discussion.
 
You @siddharthdas can make much more sense of this article than me. This article by Ben Duncan was first published in 1995 and explains that cables, crossovers and speakers are all energy storing devices (by virtue of capacitance and inductance). So let's say when we are feeding a signal of 1 Khz for example and when the signal is suddenly stopped, the voltage cannot become zero. However solidstate devices by virtue of using negative feedback, this shouldn't be a problem.



oh @mbhangui you can make sense of it too - says nothing more than the fact that "cables with notable L/C/R characteristics have artifacts"...duh.. we knew that already...I run away from audio magazine reviews of any kind - biases, I know, but mostly saves me tons of time :)
 
Cables are one "Component" which cannot ever be discussed reasonably in any forum.

Perhaps
-If you want a least lossy and nearest to true transmission of signals , then there is not doubt that one needs a well engineered cable with the least impedance and which has insignificant impedance across the audible range. Canare/Belden/Mogami to name a few for signal
- but if you do choose it as tone control assuming the system can differentiate, then its the masala you add..with no expectations of being "Neutral"..whatever that means to the at individuals ears. there are scores across the price range if you want to try that.

Of course not even talking of Power cables 😇
 
Cables are one "Component" which cannot ever be discussed reasonably in any forum.

Perhaps
-If you want a least lossy and nearest to true transmission of signals , then there is not doubt that one needs a well engineered cable with the least impedance and which has insignificant impedance across the audible range. Canare/Belden/Mogami to name a few for signal
- but if you do choose it as tone control assuming the system can differentiate, then its the masala you add..with no expectations of being "Neutral"..whatever that means to the at individuals ears. there are scores across the price range if you want to try that.

Of course not even talking of Power cables 😇
I use cables like tone control and make them as neutral as possible.
 
I use cables like tone control and make them as neutral as possible.
I guess the question is is one making the cable neutral or the sound from the system neutral using cables .

The Former is all engineering design
The Latter is an art since everything from the source material to the room and ones own ear is coloured. Of course you can still choose to keep the cables neutral and use the components/acoustics/EQ to make the sound how you want it ..and it so subjective
 
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I guess the question is is one making the cable neutral or the sound from the system neutral using cables .

The Former is all engineering design
The Latter is an art since everything from the source material to the room and ones own ear is coloured. Of course you can still choose to keep the cables neutral and use the components/acoustics/EQ to make the sound how you want it ..and it so subjective
I have a dbx 31+ 31 active analogue equalizer. Whenever I adjust with EQ they measure mind blowing, with perfect flat Frequency Response, perfect minimum phase, perfect impulse and step response - BUT - All fun and magic is sacrificed. I don't like to listen an electronically equalized setup ( analogue or digital - I don't care what others think here). From today, I may experiment if I am able to achieve balance acoustically. As I am using OB loading, it could be possible to equalize by proper speaker placement, some acoustic filtering and some modification to the baffle. If a simple wire is an degrade in audio - imagine how much degrade would happen using an electronic EQ.
 
For me there still remains a lot of confusion and little understanding of how the flat Frequency Response of a loudspeakers and equal loudness contour ( Fletcher- Munson curve) behave. If you look atvthe F-M curve the ears are very sensitive between 2khz to 5khz. When the recording engineer does his mixing he must be listening to his flat monitor speakers and adjust the Frequency Response as per his own ears F- M curves. I call this "Emphasis".

When you playback this recording at your home and assuming your speakers are flat - you are again playing the same emphasis as recorded. What I require is an " De-emphasis". The De-emphasis curve need to be inverse to the " Emphasis" curve by 6dB. I think only then the music will sound flat and your ear Transfer Function will consider that as flat with the correct equal loudness contour. I am only theorizing the above - because each time I adjust my speaker crossover or Equalize for a flat measured Response- I don't enjoy my music much though they measure perfect. If i leave the speakers connected directly to my amplifier with nothing between them and speakers- they measure similar to an inverse F-M curve ( horrible by objective standards) but they are very pleasing to listen, very nice and fatigue free. The transfer functions between mixing, playback and your ears is not clearly understood - well atleast by me.
 
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A beautiful, well-constructed speaker with class-leading soundstage, imaging and bass that is fast, deep, and precise.
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