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Chris A

Toward a Specification for Home Hi-FI Loudspeakers

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It would be very useful to have a comprehensive loudspeaker performance specification.  Like all other important systems or items that are developed by humans, there can never be universal agreement on requirements. What's important is that there is at least one comprehensive performance specification (i.e., a specification that doesn't necessarily rely on specific technologies, but rather on the sound quality emitted into a home-sized listening room). 

 

On another forum, someone posted the following recently, i.e., not me:

 

Quote

Here, then, from the experience of around thirty years and after several long and tedious blind tests, my summary of the situation in 2020, in our modern era...


[Loudspeakers]


...[An acoustic driver] produces frequencies between (x)Hz and (y)Hz at a certain amplitude (decibel) with a certain capacity of acoustical energy [coverage] according to the [on-]axis...Generally speaking the quality of sound for the human ear is obtained by achieving a linear frequency range [i.e., SPL response] which faithfully covers what we hear, 20Hz to 20,000Hz for young ears and a little less for older ones.

 

Nowadays the tools exist (DSP) to correct and achieve precise results and it does not cost very much especially compared to the so-called ''Hi-Fi'' high-end products... The rest is to find recipes for drivers that work well together: very linear frequency range (flat curve) + maximum extensions at the bottom and the top of the spectrum + amplitude capacity (power, decibels) which avoids to fall into their zones of distortions and mechanical limits.  My most recent blind test made a very clear demonstration that a $5 driver can ''beat'' a $2000 driver when EQ-corrected and SPL-adjusted, within the same bandwidth for both...In other words: a DSP can work magic and save you a lot of money.

 

Cables, amplifiers, pre-amplifiers, digital / analog converters, all of this has virtually no impact on sound quality.

Either it works, or it doesn't...or the difference is in the simplest specifications, such as power and level of distortion (amplifiers, etc.).  Everything else is esotericism. Nothing is audible to humans in the esoteric differences. Bottom line: just follow the basic prerequisites for XYZ project in terms of specifications...and common sense, then everything will be OK.

 

So the "new age" of home hi-fi has transformed home hi-fi audio to be something other than it was even 20 years ago.  No longer will the buyers of most of this hardware (and now software) tolerate esoteric capability claims and outrageous prices.  If the audio system costs a lot more than the video (flat screen), the market for hi-fi audio is beginning to disappear with younger buyers.  All the above says to me that the age of being able to (largely) pick at least the electronic components via specification is now much more a reality than it has ever been in the past.  This is in contrast to listening room acoustics, and to some degree, the performance of the loudspeakers within certain room acoustic types, but note that given reasonable room acoustics and dimensions, the ability to specify the factors that determine group preferences on loudspeaker performance (overall winners and losers), the dawn of a new regime in loudspeaker performance and therefore buying is probably occurring now.

 

Some time back, I posted a hierarchy of factors (capabilities) for home hi-fi sound quality, a version of which is posted below:

 

image.png.a34f14929f54ff46f73ec41fc4323ba4.png

 

In particular, the hierarchical capabilities associated just with the loudspeakers could look something like:

 

image.png.3545daada059ef289a58b528d8bf5eca.png

 

So for the notion of a loudspeaker performance specification for home hi-fi use to have value, the specifications need to cover at least the areas that are shown in the above loudspeaker capability hierarchy.  While loudspeakers and room acoustics still are resistant to final selection via specification, the ability to weed out the non-players using those specifications (at least for loudspeakers having more than the lowest level of performance) could now be enhanced via the use of much more comprehensive specifications.

 

Taken from another thread from last year, here is a top-level table comparing two notable Klipsch loudspeaker models in some important performance categories:

 

 

Capability

Khorn

Jubilee

1

Full-range directivity (particularly below 800 Hz)

The first production home hi-fi loudspeaker with full-range directivity, 70+ yrs. of production

Significantly improved bass bin polar directivity at higher frequencies due to reduced splay angle & distance between the two horn mouths);
The K-402 horn/K-691 has much better vertical and horizontal directivity;

crossover (~450-500 Hz) polar coverage angles vertically and horizontally without significant coverage angle mismatch or lobing

2

Modulation Distortion

The Khorn’s horn-loaded bass continues to impress experienced musicians, et al.

The Jubilee bass bin has uniformly lower harmonic distortion (HD) than Khorn. Harmonic distortion is an indicator of amplitude modulation distortion (AMD), which is the most significant form of modulation distortion at low frequencies;
2" throat compression driver on K-402 horn significantly increases the surface area of the diaphragm

3

Compression Distortion

Both the Khorn and Jubilee have inaudible levels of compression distortion at home hi-fi SPL which is much less than direct radiating loudspeakers.

4

Efficiency/Sensitivity

Both the Khorn and Jubilee have very high efficiency/ sensitivity which permit very large dynamic range operation even using very low power output amplifiers.

5

Cumulative spectral decay (especially below 800 Hz)

Both the Khorn and Jubilee have outstanding bass and HF decay characteristics due to their fully horn-loaded drivers.

6

Room dimensions/loudspeaker placement

The Khorn requires a listening room with a relatively wide lateral span of certain minimum dimension to maintain a minimum listening distance from the front face of the loudspeakers of 3-4 metres.

The Jubilee, by virtue of its time aligned drivers, does not require a large listening room or a wide spacing.  Its minimum listening distance is ~1 m

7

Near-field room absorption around loudspeakers

Both the Khorn and Jubilee are corner horns requiring room corner placement and near-field sound absorption or smooth room boundaries with no acoustically reflective furnishings out to ~2 m from each loudspeaker to suppress early midrange reflections.

1

Frequency response flatness (particularly below 200 Hz)

The Khorn’s FR flatness is nominally ±5 dB from 31 Hz—17 kHz

Jubilee frequency response flatness is a function of the dialing-in process, with ±1.5 dB from 30 Hz to 17+ kHz typical values that are easily achievable.

2

Impulse/step response

The Khorn’s IR/step response is ragged

The Jubilee’s impulse response can be made to be near perfect via use of DSP PEQs and low or zero phase shift crossover filters. 

3

Input Electrical Impedance

Khorn impedance is ragged

Jubilee input impedance is a function of the inherent driver/horn impedance for the bass bin and HF channels (bi-amped & direct coupled), and is generally very smooth and controlled

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Continuing with our discussion of requirements categories and hierarchies...

 

There are also implied requirements in non-performance areas, such as reliability, maintainability, safety, environmental, workmanship and construction, hazardous materials, transportability, usability by humans (human factors), EMI/EMC, dimensions, weight, finish/color, and packaging.

 

One of the more interesting comparisons between certain Klipsch loudspeakers from 30+ years ago is reliability.  The only parts requiring periodic maintenance are the crossover capacitors of the oldest Klipsch Heritage models--well over 20 years old, and well beyond the reliability of most brand X woofer surrounds made out of foam and other cabinet hardware and finishes that degrade over time. There apparently have been exceptions to this extraordinary track record for reliability for Klipsch--notably electronics marketed by Klipsch and certain polymer cabinets now showing up from loudspeakers made 20-30 years ago, i.e., manufacturing dates of 1990-2000.

 

Another area for maintainability.  Klipsch loudspeakers have been extremely easy to refresh via capacitor replacement in their oldest passive crossover assemblies, and some phenolic materials used in the oldest tweeters from 40-50+ years ago. Not all loudspeakers allow their subsequent owners the ability to perform periodic maintenance of the crossovers (some manufacturers pot their circuits thereby preventing maintenance except for whole crossover networks as an assembly--something most manufacturers apparently ignore supplying after perhaps 10-20 years from the manufacturing date).

 

Workmanship/construction and finish are usual discussions from these forums--the visual factors only, not the acoustic performance of the loudspeakers.  Klipsch has a solid track record in this area, except perhaps for those models produced with polymer cabinet parts that reach end of life after 20-25 years of product life.  There are Klipsch loudspeakers that are being used with updated drivers and passive crossover networks from 50-75 years ago--their workmanship withstanding the typical ravages of time that other manufacturers of other brands experienced.

 

Klipsch has never used hazardous materials or other materials that affect environmental regulations to my knowledge, except perhaps cadmium plated fasteners in the past, but these are very benign in today's terms.  EMI/EMC has been similar to other open field cone-type drivers used for woofers. With today's flat screen televisions and better isolated stereo electronics, EMI/EMC requirements are largely a concern of the past with center channel loudspeakers under CRT-type televisions.

 

Chris

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You may or may not find this interesting. I think Bryston speakers are fantastic and sonically are more similar than different than some Klipsch speakers I have owned. Of course execution is completely different. I don't want to start a this is better than that discussion. The Bryston white paper I believe discusses some of the points you are trying to make.http://www.audioreference.it/catalogs/bryston_Speaker Whitepaper.pdf

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Perhaps they hear the footsteps behind them, and are looking at a future where amplifiers really don't make much difference, except perhaps with customers trying to "wear the brand", like anything that is bought for status instead of utility.  This will apparently be a factor with a fraction of home hi-fi buyers, but certainly not the majority of younger home hi-fi buyers.  That day/age is apparently passing.

 

As far as differences between Klipsch and anyone's "brand X", I find that the relative importance, or in specification terms, "precedence" of requirements is far different.  When you look at one of the pictures that they show in their paper (whose link you posted, above), you'll see that difference in requirements precedence--in spades:

 

image.png.e9afdfb82a0fbbbf1e4a3f7222c6198b.png

 

This isn't Klipsch, and the reason why it isn't is because the precedence of the requirements for modulation distortion and coverage/directivity are much higher for Klipsch than for brand X--especially safety--which is easily highlighted by the dangerous spikes on the the bottom of the loudspeaker assembly.  They're also using approximations for line arrays which have their tradeoffs in terms of overall capabilities, or their flip side...requirements.

 

While I had planned on discussing "precedence of requirements" in more detail after enumerating the span of higher precedence requirements categories, perhaps this will serve as a place marker for that discussion.  I still have a bit more ground to cover before the full subject is really out on the table for discussion (which I will fill in mostly above in the two succeeding posts that are presently blank.)

 

Chris

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What I would like to see, more than anything, is the whole recording and reproduction industry getting together and agreeing that all recordings will be full-range and not manipulated, and playback devices engineered to protect themselves if need be.  

If it could be agreed on for overall compression, loudness, dynamic range, and frequency response, and then the devices can add whatever emphasis they want, great.  Home A/V receivers with room compensation routines & microphones can get most people close enough.  And then there's "us"...

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7 hours ago, DirtyErnie said:

What I would like to see, more than anything, is the whole recording and reproduction industry getting together and agreeing that all recordings will be full-range and not manipulated, and playback devices engineered to protect themselves if need be.  

If it could be agreed on for overall compression, loudness, dynamic range, and frequency response, and then the devices can add whatever emphasis they want, great.  Home A/V receivers with room compensation routines & microphones can get most people close enough.  And then there's "us"...

Amen...

 

However, I personally see 50-75 years of entrenched RIAA-type company culture (i.e., one size fits all mastering practices) resisting doing that--quite strongly.  In fact in many ways it's going the wrong direction.  MPAA industry (the movie industry) is now being affected by the RIAA Loudness War and "mastering for maximizing revenue" mentalities.  I assume that the earbud ethic of the original MP3 players is the root of the current low fidelity standards, and is currently driving that mentality.

 

When consumers realize that most music is mastered in lowest-common-denominator fashion, and then start buying music that's mastered for hi-fi--instead of ear buds (i.e., the current one-size-fits-all mentality)--perhaps there will be sharply increased sales of albums and individual music tracks that cater to higher fidelity, like you indicate.  All that will necessarily need to come from a consortium of audio hardware manufacturers to create more "value to the customer" and get the record giants to produce more than one released track quality that can easily be bought.  Right now, I see a lot of squeezing of the mastering guys by the record company A&R folks and recording artists that are infected by the A&R culture and subsequently become entrenched in those corporate cultural memeplexes to keep mastering costs minimized to "one size fits all". 

 

It doesn't have to be that way, but there it is presently.

 

Chris

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3 hours ago, Chris A said:

Perhaps they hear the footsteps behind them, and are looking at a future where amplifiers really don't make much difference, except perhaps with customers trying to "wear the brand", like anything that is bought for status instead of utility.  This will apparently be a factor with a fraction of home hi-fi buyers, but certainly not the majority of younger home hi-fi buyers.  That day/age is apparently passing.

 

As far as differences between Klipsch and anyone's "brand X", I find that the relative importance, or in specification terms, "precedence" of requirements is far different.  When you look at one of the pictures that they show in their paper (whose link you posted, above), you'll see that difference in requirements precedence--in spades:

 

image.png.e9afdfb82a0fbbbf1e4a3f7222c6198b.png

 

This isn't Klipsch, and the reason why it isn't is because the precedence of the requirements for modulation distortion and coverage/directivity are much higher for Klipsch than for brand X--especially safety--which is easily highlighted by the dangerous spikes on the the bottom of the loudspeaker assembly.  They're also using approximations for line arrays which have their tradeoffs in terms of overall capabilities, or their flip side...requirements.

 

While I had planned on discussing "precedence of requirements" in more detail after enumerating the span of higher precedence requirements categories, perhaps this will serve as a place marker for that discussion.  I still have a bit more ground to cover before the full subject is really out on the table for discussion (which I will fill in mostly above in the two succeeding posts that are presently blank.)

 

Chris

You miss my point. The paper states their goals and parameters in designing their speakers. I'm not referring to their speakers per se, but to the methodology used in their design and to achieve their goal. Is a standard in consistency of the type of measurements used to measure speaker performance what you are after? 

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That fact that some company uses measurements and methodology is not new--each company essentially has its own (like Toole reported for Harman/JBL in his book).  The problem is that even though each company/site apparently has some sort of design and test/verification methodology and related processes, they're not designing to the same precedence of requirements and design thresholds such as Klipsch and Danley Sound Labs use, and so don't get the same results:

 

1) full-range directivities (i.e., like the Jubilee, Khorn, La Scala, Belle, and the Danley Synergy series),

2) consistency of directivity vs. frequency through the crossover regions and below 1 kHz down to home hi-fi Schroeder frequencies (<200 Hz) and

3) low modulation distortion (AMD, FMD)

 

Chris

 

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On 5/1/2020 at 4:03 PM, Chris A said:

1) full-range directivities (i.e., like the Jubilee, Khorn, La Scala, Belle, and the Danley Synergy series),

2) consistency of directivity vs. frequency through the crossover regions and below 1 kHz down to home hi-fi Schroeder frequencies (<200 Hz) and

3) low modulation distortion (AMD, FMD)

 

Chris

 

Those should go up on a tablet somewhere as the trinity of most important requirements for home loudspeaker design. 

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Another cost discussion?

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I can appreciate the discussion on quality and qualifiers/specifications but the industry has walked off the cliff already.

 

How many people will pay for the research compared to the consumer market of the masses.  The old '70's specifications and today's measurement instruments/capability can get you to quality but the real change needs to be with the culture so we can get the quality back down to people with affordability.  This culture believe's everything can be DSP'd in and don't mess with my ear-buds.  Quality / affordability equation does mean lower margins from the astronomical amount against some product.

 

Give them something they can touch and see as quality / jewelry, now that will be another thing.  

 

As the market narrows, the price goes up.  Piling more standardization and metrics on top of it is going to continue to push cost up and reduce lying though sketchy specs, which the consumer massed depend on to some degree.

 

I agree that it would be nice to get to some higher AGREED TO standard though I think that train has left the station for most part.  If you can't touch it and see it as in a video screen resolution, it matters much less.  

 

Sorry for my issues, carry on with the great discussion. 😢

 

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6 hours ago, Schu said:

Another cost discussion?

All products are affected by cost.  The difference between good products and poorer ones (like the commodity products of home hi-f loudspeakers) is the balance of design requirements and how well their designs are executed within those sets of requirements. 

 

This is a actually a discussion that I really haven't seen elsewhere on this topic (audio components, and loudspeakers in particular).

 

Chris

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One of the reasons why I started this thread is because now I can perhaps get out on the table the things that need to be said without a lot of sniping.  Posts to the forum on loudspeaker design are probably down now in number, or at least not so focused on performance topics as they were even 2 months ago.  To me, that's a golden opportunity to discuss a topic that I've waited to broach for perhaps 10-12 years, due to the typical diffusion of discussions into lower value pursuits that typically occur.  I encourage those that don't see that value presently to perhaps hold comment until the topic opens up a little in coming days.  This topic is not a typical discussion.

 

I have a feeling that this type of discussion will ultimately benefit KPI itself (assuming anyone that is currently working for them in engineering and perhaps marketing is reading it).  But it will take some effort on my part as well as my time to get the discussion down to a level that others may recognize the value for them personally and for the manufacturer.

 

Chris

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I got this from William Cowan's Site from 10 years ago.

10 Steps To Excellent Sound

I've spent over 20 years passionately involved in audio both professionally and as a keen DIYer / hobbyist. I've learnt much about the art of audio during this time and I think my personal system can attest to that. Here I've presented my list of the ten most important things needed to achieve a truly transparent audio system. HiFi or High Fidelity has become a much used but rarely achieved goal in audio. To me, High Fidelity means true to the original, in every sense. This sounds easy in practice, but in reality, everything must be done right and this is actually very rare. Have a read of my 10 Steps below and have a think about the ramifications of these statements. I believe my current system is pretty much there, except for #1 and #5. I miss my target at the very lowest frequencies, despite having 1600W RMS powering eight high excursion 12" drivers.
 

  • 1 THD and IMD< 1% at all normal levels and frequencies
    This should keep distortion down to inaudible levels. I've seen 3% as the level where THD starts to become audible, but this does change significantly with the order of the distortion, higher orders being audible before the lower orders. This spec most likely refers to the latter.
     
  • 2 Thermal compression less than 1dB at all normal levels
    Lots of voice coil area and well designed voice coil cooling is required here at low frequencies. Higher up high efficiency can be a great benefit. When attempting to reach high output levels, a little dome tweeter or small voicecoil on a 10" woofer is just not going to be able to provide low enough thermal compression to be inaudible. Thermal compression will rob the system of macro dynamics.
     
  • 3 SNR greater than 90dB
    This specification appears easy to achieve, but in practice is quite a challenge. Attention must be paid to the gain structure in the audio chain to ensure the SNR available from the electronics is achieved in practice. All stages in the signal path should approach clipping at about the same time. Any deviation from this ideal is simply robbing the system of precious dB's of SNR. A 90dB SNR gives a noise floor of 20dB SPL in a system that is capable of 110dB output. This should be at or below the ambient noise level in most domestic environments. As the output capability of a sound system increases, high SNR becomes even more important.
     
  • 4 Response flatness +/-2dB from target above 300Hz, +/-5dB below 300Hz at all listening positions
    Pretty self explanatory, correctly designed equalisation is your friend. Correctly executed eq also has the advantage of undoing any phase errors within a drivers passband. A large well designed room and controlled directivity can also help.
     
  • 5 Output above 110dB at listening position
    This should assure sufficient output for movies or dynamic music. Remember that a 4 meter listening distance will reduce the output from most speakers by up to 12dB compared to the 1 meter output. This requires more than 122dB output at 1 meter which is a tough challenge for most speaker systems. A true line source will only reduce in output by 3dB for each doubling of distance, making this spec easier to achieve in large rooms. Very few loudspeaker systems can claim true line source behaviour at all frequencies, they are simply too short.
     
  • 6 Controlled Directivity and/or a very well treated room
    It's important to keep reflections in front of the listening position to a minimum. If reflection points exist, they can be removed with intelligently placed absorbent panels.
     
  • 7 Smooth power response or anechoic room
    The off axis response must be very close to being the same as the on axis response, or any reflections off the walls making their way back to the listening position will have a different spectral balance and will ruin the sound. Very absorbent side walls can reduce the effects of a loudspeaker with poor off axis response. The ceiling and floor reflection points must also be dealt with. It can be helpful to use a mirror to help determine exactly where the reflections are occurring.
     
  • 8 No reflections closer than 10mS from direct signal
    The ear has trouble differentiating reflections that are very close in time to the direct signal. 10mS to the first reflection will ensure these reflections don't adversely impact the sound. As the time to the first reflection becomes longer the brain
     
  • Change in frequency response of less than 1dB with change in output level
    This is closely tied to the thermal compression issue. It's a sad fact of life that many systems change their response significantly with changes in output level. It's always very telling to do a response measurement at 110dB(1M) and compare it to the response plot at 90dB. Differences of 5dB or more are common. As voice coils heat up, their DC resistance can almost double. This change in Re causes a huge shift in driver parameters and de-tunes your carefully aligned boxes. The higher order boxes (Bass Reflex, Band Pass etc) suffer more than the low order alignments such as the sealed box.
     
  • 9 Bandwidth from 20Hz to 15KHz
    This should cover all audible input signal for most of us.

    10 Now the controversial part.

    Having a look at this list you might notice that most of the problems highlighted are room and loudspeaker related. It's a sad fact of life that this is where most of the non linearities in a system exist. Apart from SNR there is really nothing that's electronics related, and even that has more to do with the application of the electronics than it's actual design. Even the cheapest CD/DVD source will be "blameless" in even a high end sound system. VERY FEW components can't achieve 20Hz-20KHz, 0.1% distortion and 100dB SNR. If they can't, they don't have a place in ANY high end sound system - PERIOD. If any component will colour the sound AT ALL it is not worthy for use in a high end sound system.
    Some of you might think "where do all the fancy electronics, valves and high end cables fit in?" Well, IMHO, the fancy electronics and cables are there to make you feel good about your system, and they do. You are simply kidding yourself if you think a $500 cable pair will sound different to an interconnect using Neutrik connectors and good quality Belden microphone cable, or similar. As long as the connectors are clean and sound, the cable capacitance is low enough not to impact the top end and the shielding is sufficient not to impact the SNR, there is no benefit spending more money on the interconnects. This money will have a far greater effect if spent where it counts, on the speakers and room. I maintain that most of the budget should be spent on the speakers and the room they are in. The end result will always be better than dumping a pile of money on the electronics and signal path. Valves are another can of worms. Sure they can give you a "warm glow" but to base a high fidelity system around a valve amp is a real challenge. I have not yet heard a valve based system that was not coloured. Lacking in dynamics usually describes them too.

    My Perspective on audio is from a purely engineering based perspective, however I can see where tweaky stuff has it's place. It helps the local audio shops that we buy CD players and electronics from keep their doors open. There is not a lot of profit in main stream electronics these days and the retailers need their little golden egg.

    The funny thing is it's actually pretty easy these days putting together a reference class audio system for not too much money. To tick all the boxes in my 10 steps (above) all you would need to do is stick a pair of, say, Danley SH50's in the corner of your room, power them with a simple 100W RMS per channel amp, team the lot with a sub that can match the output of the SH50's (Horn, IB, multiple sealed or vented boxes) and you're done. The Danley boxes come to mind because they are one of the few well engineered full range loudspeakers on the market that can meet my output, distortion and directivity specifications laid out above. Another loudspeaker that would provide what I am after is the Gedlee Summa. If the amplification and crossover are from one of the many pro sound manufacturers (many honest well priced products), the entire system could be put together for probably $10K and rival the monitors in most recording studios. The biggest hurdle would be to make it all look pretty in a domestic environment, but as I've proved with my Unity build in, even that's possible. Please note that I have no affiliation with Thomas Danley or Earl Geddes, I do however have great respect for their electro acoustic engineering ability.

     
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2 minutes ago, ClaudeJ1 said:

Well, IMHO, the fancy electronics and cables are there to make you feel good about your system, and they do. You are simply kidding yourself if you think a $500 cable pair will sound different to an interconnect using Neutrik connectors and good quality Belden microphone cable, or similar. As long as the connectors are clean and sound, the cable capacitance is low enough not to impact the top end and the shielding is sufficient not to impact the SNR, there is no benefit spending more money on the interconnects. This money will have a far greater effect if spent where it counts, on the speakers and room.

I'm just quoting William Cowen here, and I agree. This has been my experience as a Klipsch/Danley fan for over 50 years (I was 14 when I had a paper route 1 block away from a Detroidt Klipsch dealer, long out of business). That is when I first heard Khorns, and it's in the days when PWK used to fly his plane to visit his dealers. Talk about personal service!

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So we're just grazing the surface of the topic on the above two posts by Claude. 

 

Cowan's comments are an example of a set of loudspeaker + audio electronics + room acoustics (i.e., "a home hi-fi audio reproduction system"...lets call it "HFARS" for lack of a better term) that represent a "point design" of requirements that can be designed to.  Several designs can be made from that set of requirements, but many more designs can be made if we alter the requirements thresholds and the collective membership of requirements in our "design-to" set of requirements. 

 

(Several concepts are broached above but I think that most people will have a feel for what is to come.)

 

There are also other collections or sets of requirements, like the set above but the thresholds and the relative importance of each requirement (something that wasn't discussed in the requirements stated above...i.e., how to trade among requirements that conflict with each other and with the target price of the [loudspeaker, audio electronics, room acoustics, or full "HFARS"]). 

 

That is the topic that this thread intends to explore.  It isn't a typical home hi-fi forum topic.  It is, however, something that is applicable to almost any [engineering + marketing + product support] domain that requires more than one simple product in order to do perform its core functions or capabilities, that is...something that behaves more like a system than a simple product having a single function.

 

It's also a subject that I actually know a great deal about and have worked in most of my engineering career (...in excess of 40 years).  So the topic is a bit deep but readily accessible for those inclined to wanting the answers to the questions"why?", and "what if I wanted something a little different that better meets my needs?".

 

Chris

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"....

There are also other collections or sets of requirements, like the set above but the thresholds and the relative importance of each requirement (something that wasn't discussed in the requirements stated above...i.e., how to trade among requirements that conflict with each other and with the target price of the [loudspeaker, audio electronics, room acoustics, or full "HFARS"]). 

..."

 

Chris, I think this will end up being the biggest hurdle: The unwillingness or inability for folks to prioritize. 

For some weird reason, people are far more comfortable when they throw their hands up in the air and declare "everything is important". 

 

Good luck,

-Tom

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Thanks Tom.  Yes....and I probably know this at least as well as you. 

 

What the difference is--is that the tools and processes used to find the agreed-to requirements sets (and their relative priorities or precedence) based on understanding customer needs--in a collective way--do exist, and are quite accessible and effective.

 

This is just like any other system design problem.  I find that most people haven't been exposed to effective design processes (even engineers), but that doesn't mean they don't exist, and that they are not used to develop requirements sets--also called "specifications".

 

Chris

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Perhaps I need to state the following: 

 

There is the commonly held belief that most products that currently exist are optimal in some way, that is, that they can't be improved upon substantially. 

 

I've found that this is generally not true...that most products, and especially systems of products, are not that well designed to customer needs--except perhaps the lowest cost/lowest value products that can be thought of. 

 

That's the motivating factor behind this thread--the knowledge that most systems of products are actually not that well thought out, and that there is significant value (to the customers)  that is still yet to be accessed.  That has been my direct experience over the past 20-25 years. 

 

In the 1980s, there was a time in the auto industry that was challenging for the US consumer and even more of a challenge for US automobile manufacturers.  The problem was that someone else in the world found a way to produce better products at lower cost, much more reliably and with greater customer satisfaction--even though the automobile was considered at that time to be a commodity item that had been optimized in its design, manufacture, and product support. 

 

The same situation exists (presently) in other industries.

 

Chris

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