The Insanity of Marketing Disguised as Science in Loudspeakers

[tonmeister]

A speaker that has an obvious flaw like the tweeter level being set too high is easy to remember so don't discount our auditory memory for obvious sonic signature differences. I can vividly describe how a gourmet steak from my favorite restaurant tastes compared to a Denny's steak and when I taste that gourmet steak again at a later date, my senses aren't shocked or surprised b/c they anticipate the stimuli I remember from past experiences. If the differences between speakers are subtle than I agree that controlled blind tests like the ones Harman does produces more consistent results b/c they help eliminate the bias of perception and in Harman's case, they also remove positional bias.

Long term testing is used to determine how you feel about the speaker after experiencing it over a length of time with your own program material and in your own listening space. I still tend to place more weight on this than short term instantaneous comparison testing. How many of you have test drove a car, loved it at the time you test drove it only to be disappointed a few months later? Perhaps this happened b/c you noticed its a bit bouncier or not as fast at accelerating under certain driving conditions. I've experienced buyers remorse many times when purchasing cars.

Harman probably has the best testing facility in the country to do comparative blind testing. However, by rotating speakers on a platform, an instantaneous switching between speakers isn't possible so auditory memory which helps detect subtle differences will be impaired. The question is what bias is worse - reduced auditory memory or positional bias? I'd be curious to hear Sean's opinion on that.

Personally, I like to be able to engage long term individual testing and instantaneous switch testing of speakers to get a good baseline of performance.

Impedance graphs can certainly reveal design flaws and help explain why a speaker can sound different when being driven by different amplifiers, but they don't directly dictate perceived sound quality.

Gene,
To answer your specific question about auditory memory versus positional effects, and which one has the biggest influence on our perceptions:

1. We've found that loudspeaker positional effects can influence the listeners' loudspeaker preference ratings by 25-30%. IF you don't control these positional effects, the loudspeaker position itself be the determining factor of the test results swamping out any loudspeaker effects. In my view, that is a huge effect that must be controlled if the test results and their interpretation are intended to be accurate and meaningful. We control positional effects via a pneumatic speaker shuffler that puts each speaker in the same position within 3-4 seconds. If you cannot afford a speaker shuffler, another option is you can repeat the test n-number of times swapping the different speakers among the different n-number of positions. If the room and speaker setup are acoustically symmetrical (e.g. rectangular), you might get away with testing each speaker in an inside and outside position, a method we used before we had the speaker shuffler. You can confirm whether the room and setup are acoustically symmetry by acoustically measuring each speaker in each position at the listening position.


2. We don't know too much about auditory memory and its' effects as it relates to judging loudspeakers. That would be an interesting research project. But clearly this becomes more of an issue as the audible differences among stimuli decrease. For high quality amplifiers and audio CODECS the audible differences are an order of magnitude smaller than those found amongst different loudspeakers, and the time gap between comparisons needs to be almost 0. Based on my knowledge and experience, I would gladly trade-off auditory memory effects related to the time gap between loudspeaker positional substitutions (on the order of 2-4 seconds) for control of positional effects since the latter are usually have a more significant impact on the results.

 

[tonmeister]

Now with speakers there are usually large easily identifiable differences between speakers, unlike other parts of the audio chain. So this helps.

However, I think testing speakers with other than highly trained listeners with well developed acoustic memories means nothing at all: - zero.

In my opinion only natural instruments in a known acoustic space can be used for loudspeaker evaluation.

In other words, the panel need to have heard musicians in a space in which they were recorded with the same music in a proximate time period. I firmly believe anything else is useless.

Pop and electronic instruments are hopeless for speaker evaluation.

That is why I use recordings made in a venue I'm familiar with for critical evaluation. If there is a CD available were I have heard a concert I buy it.

When I was at Mahtomedi, MN for the concert celebrating 30 years of Pipe Dream broadcasts I bought a well recorded CD on the Pro Organo label.

The main reason that I made so many recordings over the years, was to evaluate speakers. To go from auditorium to the control room and hear it over my monitor speakers, really developed in me an enormously heightened awareness for the evils of speakers, and a steady improvement in results.

Measurements get you some of the way, but all the good designers I have known voice to a very large extent by ear. The good ones make changes to the design over long intervals after first getting the speaker reasonably balanced.



This leads me to believe that the surest way to good sound in the home is to learn to design and build your own speakers. I'm unusual, in that I have never owned a set of commercial speakers. I have always listened to speakers I designed and built. So is there a selection for a particular
sound field? Yes, there must be. Friends and acquaintances have said my speakers have a definite stamp to them, which is usually described as full bodied with a very tight bass. Musicians in particular note the correct space around instruments. I think they mean by that, that the sound does not seem to emanate form the speakers, and the cues from the original acoustic space are preserved. They seem to like them. In Grand Forks we had a listening group and we all had very decent speakers. We would rotate venues, but overtime it seemed to drift more and more often to my place. I think that it all comes down to voicing to the space among other things. I believe speakers like organs have to be voiced to their space.

When I was recording, by monitors had switches on the back to subtley voice them to my most frequent monitoring venues, such as the Green Room at the Chester Fritz auditorium Grand Forks.

The above is yet another inducement to build ones own speakers. The down side is years of progress, but it is a fascinating journey, to Peter Walkers "Closest Approach to the Original Sound." That really has to be the goal of acoustic engineering.

I have to respectfully disagree with two of your assertions made above.

1. The notion that loudspeaker listening tests are only valid using recordings of natural instruments is not necessarily true. How "accurate" and "natural" the instrument sounds depends on the skill of the recording engineer and the accuracy of the monitors/listening room interface through which the recordings were made. This is all part of the circle of confusion that exists within the recording/playback chain, and unless the acoustical performance of the playback chain is well-defined, then all bets are off in regards to how accurate the recording will be. There are currently no standards in the music industry that define the performance of the playback chain, and as a result, the quality of all recordings remains highly variable.

The notion that listeners can't discriminate and formulate reliable, valid opinions of loudspeakers using pop/electronic program (versus natural instruments in an acoustic setting) is contrary to what our research tells us. Whether the instruments are natural or electronic becomes moot when you employ a multiple comparison protocol in the listening tests where multiple speakers are compared. In this case, the colorations in the recording are common to all speakers under test. What remains are audible differences among the loudspeakers that become the focus of the listeners' evaluation. Also, through listener training and experience, the listener becomes familiar with the program material, and to some extent, learns how it should sound. The fact that we are able to predict listening test results (using sthis program material) based on a set of comprehensive anechoic measurements, and listeners prefer the loudspeakers that measure the best, indicates that using such material works.

Secondly, the spectral bandwidth, density and continuity of the program material are properties highly correlated with listeners' ability to discriminate among the different loudspeaker under test. In my experience, pop/electronic music on average meets this criteria better than jazz and classical music. See the graph in this article that shows how well listeners identify simulated spectral distortions with different music programs. After pink noise, the best programs for detecting spectral distortions in loudspeakers tend to be pop music -- not classical. As far as evaluating spatial characteristics of loudspeakers, this has a lot to do with the recording techniques used to make the recording.

2. I wouldn't recommend anyone to try and design their own loudspeakers at home, as a general rule. Believe me, over the years I measured and tested many speakers built by amateurs (including some in the loudspeaker business) and the results are usually disappointing. Besides requiring some mechanical engineering and electroacoustic knowledge and skills, you need comprehensive (high spatial and frequency resolution) anechoic measurement data for each driver in order to optimize the design. Otherwise, you're working in the dark, with one hand tied behind your back.

 

[Bizarro_Stormy]

hmmm...

Otherwise, you're working in the dark, with one hand tied behind your back.

Sean...
You just described my favorite work environment...

 

[GranteedEV]

2. I wouldn't recommend anyone to try and design their own loudspeakers at home, as a general rule. Believe me, over the years I measured and tested many speakers built by amateurs (including some in the loudspeaker business) and the results are usually disappointing.

Sean, I respectfully disagree. Sturgeons revelation applies here too, but not any less so than in the commercial realm.

It's safe to say that
1) The designers of the drivers themselves, were professionals.
2) Above the shroeder frequency, quasi-anechoic measurement techniques are adequate for most purposes. Below the shroeder frequency, i'm sure you know how it goes...
3) Crossover design software like Passive Crossover Designer is rather adequate, as is enclosure design software like Martin J King's MathCAD worksheets.
4) "Amateurs" are unrestricted by commercial considerations / pressures, and can be more receptive to the fruits of research "Professionals" stuck in their ways.
5) The DIY community, fueled by the internet, is very capable of doing things the professional community can't be bothered with. For example, check out the fruits of this thread.
6) Amateurs can actually experiment with things that seasoned vets might write off based on ancient internal research. Like a RAAL tweeter found in the "amateur"Philharmonic speakers.
7) Research itself can be flawed or incomplete, even if it seems right. Andrew Jones at TAD has in the past commented that there is in fact a human element to loudspeaker design, something he found lacking during his time at KEF.
8) Amateurs are not restricted to passive crossovers. This means placement specific baffle step compensation, less restrictions on driver matching, and other issues can be avoided. It's more versatile to go active.
9) Amateurs know the final room a speaker will be in and can decide on an exact power response curve that best suits it. Pros are still limited to a "one-size-fits-all" curve, with the occasional complex level controls on ultra-high-end gear.

I'd imagine that in the 70s, 80s, 90s, maybe most of the 00s your assessment would have been a valid one, but i'm willing to wager against it presently. The knowledge, and willingness to apply it, is greater than I imagine you estimate.

 

[Irvrobinson]

Irv, I would love to hear your subjective impressions/audition of a Gedlee Abbey or Summa...

Have you ever heard a Gedlee speaker?

When I was shopping for speakers and considering the Linkwitz Orion, a few people on Audiogon mentioned the Summa. I never found a way to audition them without going to MI, which wasn't happening. I usually don't pay much attention to the testimonials on manufacturer web sites, but a couple of Gedlee's intrigued me. Nonetheless, I wasn't willing to take such a pricey chance. I hadn't read ADTG long enough to catch his form of risk taking. ;-)

 

[AcuDefTechGuy]

This is why the concept of people settling for speakers with less than 90db makes me laugh. When an instrument calls for 105db and your speaker is running into severe power compression delivering it (probably your amp as well), then you'll hear it for sure. The 6db drop whenever distance is doubled is massive.

Who listens to 105dBA?

PENG attends live symphonies. He brought along his SPL meter to measure how loud the concert was. I recall PENG said that the loudest SPL reading was no louder than 90dBA.

 

[AcuDefTechGuy]

I hadn't read ADTG long enough to catch his form of risk taking. ;-)

Doh.

I actually heard the Orion, Salon2, & KEF 201/2 before I bought them.

The only 3 speakers I bought without audition were the NHT SuperZero, P362, & Phil3.

 

[gene]

Gene,
To answer your specific question about auditory memory versus positional effects, and which one has the biggest influence on our perceptions:

1. We've found that loudspeaker positional effects can influence the listeners' loudspeaker preference ratings by 25-30%. IF you don't control these positional effects, the loudspeaker position itself be the determining factor of the test results swamping out any loudspeaker effects. In my view, that is a huge effect that must be controlled if the test results and their interpretation are intended to be accurate and meaningful. We control positional effects via a pneumatic speaker shuffler that puts each speaker in the same position within 3-4 seconds. If you cannot afford a speaker shuffler, another option is you can repeat the test n-number of times swapping the different speakers among the different n-number of positions. If the room and speaker setup are acoustically symmetrical (e.g. rectangular), you might get away with testing each speaker in an inside and outside position, a method we used before we had the speaker shuffler. You can confirm whether the room and setup are acoustically symmetry by acoustically measuring each speaker in each position at the listening position.


2. We don't know too much about auditory memory and its' effects as it relates to judging loudspeakers. That would be an interesting research project. But clearly this becomes more of an issue as the audible differences among stimuli decrease. For high quality amplifiers and audio CODECS the audible differences are an order of magnitude smaller than those found amongst different loudspeakers, and the time gap between comparisons needs to be almost 0. Based on my knowledge and experience, I would gladly trade-off auditory memory effects related to the time gap between loudspeaker positional substitutions (on the order of 2-4 seconds) for control of positional effects since the latter are usually have a more significant impact on the results.

Sean;

Thanks for popping in this thread and participating. I leaned too well of the issue of positional bias when we conducted our 2010 Floorstanding speaker face off.

When we compare speakers, we arrange them as follows:
AB BA
and going forward, we tend to use the 2 sweet spots in our sound room for our panel of listeners which are dead center front and back row.

We obviously can't go through all the speaker positional and seated trials you suggest b/c it would just take insanely long, especially when dealing with 4 pairs of speakers at a time and more than 2 listeners.

As for rotating the speakers, I love the idea, but I do have some concerns with doing that.

I honestly don't think positional bias could ever be fully eliminated. Why? because how the speaker "plays" into the room (and ultimately sounds) is an inescapable result of placement in the room. Not even a rotating platform which exactly positions speaker A in the same place as speaker B removes bias. Why? Because Speaker A may sound "better" with that particular placement in the room than speaker B. Change the position of the speaker, or the listening position, and in may be a different story. You can even have both speakers positioned similarly, but one sounds better toed in and the other sound better with no toe in.

I've spoken to many well respected loudspeaker engineers over the years and they all seem to indicate when finishing up a speaker design, they find it can take a fair amount of listening (and measuring) in different environments, or with the speakers in different positions, to verify why a speaker sounds the way it does, and what they like or feel could be improved with the speaker design. It can be a long process. On the other hand, earlier on in the design process, it can take just a few seconds of listening to verify what one does or doesn't like about the sound of a speaker. It is a very subjective process either way not matter how objective one attempts to make it.

Again, this is why I am such a stickler on extended listening sessions with each speaker over a range of a few days/weeks. The same with cars. A car may drive great out of a showroom, but it usually takes weeks of driving down familiar roads to determine if you really like how the car handles and rides.

As for audio memory, yes I totally degree, its a function of how substantial the difference in sound there is between two stimuli. When comparing DAC's I have to do instantaneous switching but with speakers, there is definitely more of a grace period.

 

[gene]

2. I wouldn't recommend anyone to try and design their own loudspeakers at home, as a general rule. Believe me, over the years I measured and tested many speakers built by amateurs (including some in the loudspeaker business) and the results are usually disappointing. Besides requiring some mechanical engineering and electroacoustic knowledge and skills, you need comprehensive (high spatial and frequency resolution) anechoic measurement data for each driver in order to optimize the design. Otherwise, you're working in the dark, with one hand tied behind your back.

I agree about the designer needing skills (both electrical, mechanical and common sense), but I don't agree that anechoic chambers are a necessity. This is especially true with subwoofer design. Ground Plane is a superior method of measuring low frequencies to anechoic and much more practical than 4pi (subwoofer on a 90ft pole).

Measuring fullrange speakers is certainly easier to do anechoic, but a good designer knows how to eliminate the room from the measurement and like Philip said, you can't accurately measure below 100Hz in most anechoic chambers, thus you can't properly compensate for baffle step. Of course you can implement a correction curve in an anechoic chamber to get around this, but it involves making measurements outdoors again.

 

[GranteedEV]

Have you ever heard a Gedlee speaker?

Nope. I don't expect a SEOS DIY build will be too far in concept, though. The SEOS is basically a super-elliptical design strongly inspired by Geddes' conical designs... throat entry angle matching intended driver exit angle, oblate spheroid geometry, extremely low diffraction, 90 degree pattern control from ~900hz up to ~16khz. Trying to figure out how to shape and attach the correct reticulated foam to the waveguide though, because that's the last key design feature of Geddes' speakers. The super-ellipse is complex but the advantages are better driver spacing and it also eliminates the on-axis diffraction nulls caused by an axi-symmetric waveguide (not that you should listen to these on-axis... the goal is to crossfire them)

 

[tonmeister]

Sean, I respectfully disagree. Sturgeons revelation applies here too, but not any less so than in the commercial realm.

It's safe to say that
1) The designers of the drivers themselves, were professionals.
2) Above the shroeder frequency, quasi-anechoic measurement techniques are adequate for most purposes. Below the shroeder frequency, i'm sure you know how it goes...
3) Crossover design software like Passive Crossover Designer is rather adequate, as is enclosure design software like Martin J King's MathCAD worksheets.
4) "Amateurs" are unrestricted by commercial considerations / pressures, and can be more receptive to the fruits of research "Professionals" stuck in their ways.
5) The DIY community, fueled by the internet, is very capable of doing things the professional community can't be bothered with. For example, check out the fruits of this thread.
6) Amateurs can actually experiment with things that seasoned vets might write off based on ancient internal research. Like a RAAL tweeter found in the "amateur"Philharmonic speakers.
7) Research itself can be flawed or incomplete, even if it seems right. Andrew Jones at TAD has in the past commented that there is in fact a human element to loudspeaker design, something he found lacking during his time at KEF.
8) Amateurs are not restricted to passive crossovers. This means placement specific baffle step compensation, less restrictions on driver matching, and other issues can be avoided. It's more versatile to go active.
9) Amateurs know the final room a speaker will be in and can decide on an exact power response curve that best suits it. Pros are still limited to a "one-size-fits-all" curve, with the occasional complex level controls on ultra-high-end gear.

I'd imagine that in the 70s, 80s, 90s, maybe most of the 00s your assessment would have been a valid one, but i'm willing to wager against it presently. The knowledge, and willingness to apply it, is greater than I imagine you estimate.

1) There are many examples of poor OEM drivers that appear not to have been competently designed. You can't assume they are all good unless you actually measure them and confirm yourself. When you put them into a box you need to measure them again to include diffraction and acoustical interaction effects.

2) Quasi anechoic gated measurements are fine as long as you have a long time measurement window. Otherwise, you have insufficient frequency resolution, which means you cannot accurately measure and discriminate between medium- high Q resonances. This matters because the perception of a resonance is dependent on its Q-factor. We use 48--points per octave log-spaced from 10 Hz to 48k to start with. I'll let you calculate how long a time window you would need to generate that much frequency resolution using time gated measurements.

So, in non-anechoic spaces you can resort to near-field measurements of the woofers and ports, try to combine and splice them with the far-field measurements (much like Stereophile does) but this is a tricky process at best. When I see these type measurements done with speakers we've tested anechoically, they often don't look the same below 150 Hz.

Also, if you want to measure low level amounts of distortion and conduct repeatable measurements you need a very quiet, controlled room.

3) Yes, there are affordable software tools available for network design but the simulation/model is only as good as the measurement data you put into them (see points 1 and 2).

4) This statement seems silly and more of an opinion than fact. But calling "professionals" stuck in their ways suggests you have a personal bias against professional loudspeaker designers.
6) Another personal opinion
7) I'm not sure what your point here is. Without research, there wouldn't be much new knowledge or progress in audio. I agree we don't know everything there is to know about loudspeakers, room acoustics and perception, which means there are more scientific research opportunities. I'm grateful for this since I will continue to have a job until we know everything.
8) Neither are professionals restricted to passive crossovers. Multimedia speakers are nearly all active as are most professional speakers. Whether a crossover is active or passive you still need accurate comprehensive measurement data.
9) How do you decide what the correct sound power measurement is for a particular room? What are the salient acoustical features of the room and the loudspeaker (e.g. directivity) that dictate what the ideal sound power response should be? And once you decide what that is how to you confirm that you've achieved it? Again, you can't circumvent the fact that you need to be able to make comprehensive anechoic acoustical measurements of the loudspeaker.

I am absolutely sure that a competent amateur?DIY can build a well-designed loudspeaker, particularly if they have the right tools and measurements. My original comment was aimed at those who don't.

 

[Irvrobinson]

An excellent paper about what GranteedEV is discussing:

http://www.pispeakers.com/Pi_Speakers_Info.pdf

And a very interesting web site.

I never would have guessed you were a horn guy...

 

[TLS Guy]

Great idea, but it must be hard to do and I would consider myself lucky if I can own even just a couple of such CD. It would be a little easier for people who frequent concerts.

Actually I have quite a few.

I have the Vanska Beethoven series on SACD from BIS recorded in Orchestra Hall, where I attend concerts regularly. I have just bought the Sibelius No 2 same forces, same venue. I have heard the same ensemble and same conductor perform that twice at Orchestra Hall in the recent past.

I picked up a CD at Mahtomedi when I attended a concert there two weeks ago.

That instrument is powerful with prodigious bass, and well voiced to the Church. I have played that CD on my speakers in Eagan, but not at concert spl, because we have shared walls and I'm only running 90 watts to each speaker. The sound was pretty accurate, but the En Chamarde trumpets lacked a little sizzle.

I played it on B & W 800D with 400 watt per channel Macs. I could may be just about get to the spl I heard in the Church. The perspective was moderately well preserved. The midrange driver was starting to sound stressed, and the En Chamarde trumpets had a little too much reed over the bell of the pipe.

I played it at Benedict and could achieve performance spl with easy, especially in the bass and the En Chamarde trumpets blazed just like they did in the auditorium. Nothing sounded stressed. It was effortless like the instrument, with the perspective well preserved.

I have discs from Downside Abbey were I went to school. I have BDs from Covent Garden that I know well.

I almost certainly have quite a few more I can't think of now.

 

[GranteedEV]

1) There are many examples of poor OEM drivers that appear not to have been competently designed. You can't assume they are all good unless you actually measure them and confirm yourself. When you put them into a box you need to measure them again to include diffraction and acoustical interaction effects.

Absolutely no doubt about it. But this is where a cooperative community is a significant factor unlike competitive professional environment.

2) Quasi anechoic gated measurements are fine as long as you have a long time measurement window. Otherwise, you have insufficient frequency resolution, which means you cannot accurately measure and discriminate between medium- high Q resonances. This matters because the perception of a resonance is dependent on its Q-factor. We use 48--points per octave log-spaced from 10 Hz to 48k to start with. I'll let you calculate how long a time window you would need to generate that much frequency resolution using time gated measurements.

I understand the upper limit, but I don't quite follow the 10hz lower limit. I'm sure you can elaborate. As far as I can tell, drivers themselves don't normally have significant resonances this low, and box/room resonances/standing waves can be simulated, and that the the room will dominate much of the response anyways. It's my understanding that a klippel test shows most of what I need to know at these frequencies, and again the "community" aspect shouldnt be under-estimated.

So, in non-anechoic spaces you can resort to near-field measurements of the woofers and ports, try to combine and splice them with the far-field measurements (much like Stereophile does) but this is a tricky process at best. When I see these type measurements done with speakers we've tested anechoically, they often don't look the same below 150 Hz.

For sure. But again, to what extent does it matter in-room at these frequencies?

Also, if you want to measure low level amounts of distortion and conduct repeatable measurements you need a very quiet, controlled room.

Very true. Assuming of course, -70db levels of distortion are a design priority. If the distortion in a room is below the noise floor of the room it's intended to play in, I guess I jist don't follow.

3) Yes, there are affordable software tools available for network design but the simulation/model is only as good as the measurement data you put into them (see points 1 and 2).

100% agreement. But again, if the crossovers are at, say, 400hz, why did my time gate need to extend to 10hz?

4) This statement seems silly and more of an opinion than fact. But calling "professionals" stuck in their ways suggests you have a personal bias against professional loudspeaker designers.

Absolutely not. My only point is that, professional or amateur, there is still an individual aspect. So when B&W puts out another speaker with a 6.5" driver operating through its kevlar breakup crossed at 4khz to a flushmount 1" tweeter, or a DIYer does the same, I'll call them out.

As far as opinions, yes they are, but your blanket statement earlier regarding "amateurs" vs "those with tools and professional training", I too consider an opinion.

7) I'm not sure what your point here is. Without research, there wouldn't be much new knowledge or progress in audio. I agree we don't know everything there is to know about loudspeakers, room acoustics and perception, which means there are more scientific research opportunities. I'm grateful for this since I will continue to have a job until we know everything.

My only point, is strict adherance to the measurements or DBT alone can be a problem approach. You yourself have in the past have pointed out how certain design concepts have measured / performed in the past. I've seen you downplay things like ancient Tannoy Coaxials and some Martin Logan Electrostats, and in ways implied that the results are all-encompassing even though, for example a modern KEF Coaxial or BG Radia planar may not measure anything like those. And that is the point... that an adherance to past research can actually stifle progress or innovation. All research has a budget, and that itself is a problem. I don't think I need to explain that to you of all people.

I also find it hard to believe that this speaker for example,

wouldn't be improved by a cheap LCR filter on the 8" aluminum cone. But if that's what that company's testing shows.. maybe some "human" decision making isn't a bad idea. Is the extra cost really that harmful? Maybe you agree with the KEF side of things with your experiences, or maybe you don't based onyour knowledge... all I know is that a (maybe naive) human being's reaction to that graph will differ from an accountant-with-research.

I'm the last person you'll find on these boards to ever reject research, but i'm willing to criticize it where it's dated or not useful on a grand scale. I see a lot more innovation coming out of the DIY community than out of the professional community and that isn't a knock on any professional designers. They have their constraints. I would not criticize KEF for cheaping out on a notch filter, but I also feel that that's a place where an amateur, moot or not, will have their bases covered because what's $$ for 1000 units is ¢ for 2, maybe 3.

I think when you're dealing with "thresholds of audibility" the research often seems inconclusive, but generally sufficient to cut costs.

8) Neither are professionals restricted to passive crossovers. Multimedia speakers are nearly all active as are most professional speakers.

You yourself said it "Multimedia and professional speakers"... which leaves out a significant market.... the one most of us here are normally interested in. You expect me to buy that the Salon2s, for example, wouldn't likely have used three 4-ohm versions of the same 8" drivers, if the design criteria allowed for a built in amp in line each driver? I'm not making any implications here but I find it hard to believe there wouldn't have been some benefits from holistic performance perspective.

9) How do you decide what the correct sound power measurement is for a particular room?

Always start with similar sound power curves to what professionals seem to favor (increasing DI as frequency rises, don't worry about crossover nulls). That's the speaker. Once it's in the room and intended listening point, measure it. Start by dealing with boundary effects, and then focus on the ;;;;;shallow;;; frequency response rolloff or shelf above ~2.5khz subjectively. It really shouldn't take much more than a 2db/decade rolloff of axial HF response to make a pretty notable change in the sound power response.

And once you decide what that is how to you confirm that you've achieved it?

That's a good question. How do the professionals know they've acheived a fits-all power response curve that works perfectly in ;;;;;my;;; room? The answer to both is a negative as far as I can tell. DBT, SBT, SIGHTED,..... none will answer that question nor will anything else. This is the end of the line, where preference necessarily but unreliably comes in, but only to the extent where wholistic measured performance is not compromised. Even if 70% of people did prefer a bit more HF energy, does that make it more correct to the person whose home the speaker will be in? Does one rebuild the living room from scratch by the books (whatever that is) for perfect neutrality? Or is just that little bit of voicing by ear over long amounts of time actually acceptable after all for the speakers we ourselves will be listening to???

In general, "voicing" should never allow a break from design goals (iE maybe +/- 2db anechoic listening window response). ...If a well measuring speaker needs anything more than 0.5db - 1.5db axial (and thus power) response fudging, then the DIYer like the professional should reexamines the design and its shortcomings. Nothing foolproof in this world. Including a lot of speakers designed by companies WITH anechoic chambers and DBT.

Again, you can't circumvent the fact that you need to be able to make comprehensive anechoic acoustical measurements of the loudspeaker.

...yes, But you still don't need an anechoic chamber to do it. It just makes things easier.

I am absolutely sure that a competent amateur?DIY can build a well-designed loudspeaker, particularly if they have the right tools and measurements. My original comment was aimed at those who don't.

Alright, fair enough

 

[krabapple]

Thanks and quite frankly I've bottled up my opinions from editorials for so long, I felt like I finally wanted to vent my thoughts (correct or not) in an editorial piece and I was expecting a wide reaction like I've seen on this forum.

I try not to stroke my ego by touting my credentials too much. I am always humbled by folks like Dr. Sean Olive & Floyd Toole that dwarf my knowledge and experience in these areas. I enjoy learning from them but I also don't blindly accept published results, even from them, without questions raised in my mind.

I'm aware of only a few manufacturers who publish papers with DBT results -- Harman is one, Pioneer's Japanese research arm another that come to mind off the top of my head. So, will you tell us just who you are referring to when you claim, for example, that manufacturers' published DBTs suffer from 'familiarity bias' and that the researchers have not considered this? Can we lay that claim to rest about Harman at least? If you've actually read Toole's and Olive's papers you know they have brought in outside listeners for their DBTs, as well as used Harman employees. (And much of the early Toole paper work was done for the Canadian NRC, not a manufacturer)

 

[GranteedEV]

An excellent paper about what GranteedEV is discussing:

http://www.pispeakers.com/Pi_Speakers_Info.pdf

And a very interesting web site.

I never would have guessed you were a horn guy...

Don't forget, ;;your;; Salon2s use an elliptical waveguide on the tweeter as well, which makes you a "horn guy". It matches the directivity index of the 1" tweeter to the 4" midrange. That it boosts forward radiated sound at the bottom of the passband (and thus max SPL) is a bonus but not the primary design criteria AFAICT.

Geddes' OS and the SEOS... they're big but they're waveguides at heart - designed for pattern control and minimal "horn sound" more than anything.

Yes they use compression drivers and the de250 has a bit of a mylar diaphram breakup near 16-17khz if you can hear that high.

They prolly make crappy horns as far as maximum SPL is concerned, but a compression driver can play louder than any dome tweeter.

They're pretty constant directivity so they actually have more dispersed high frequency energy at the top than a beaming dome. So the axial response should roll off a bit more than a dome you might leave flat.

At 90deg the pattern control is narrower than your Salon2 which i'm randomly guessing is ~120deg above 2khz.

Pattern control begins around 900hz so most of the upper midrange is "dry" or clinical if toed in. You gotta crossfire to ensure some delayed lateral reflections.

 

[Rickster71]

I have to preface this by saying I'm all for speaker measurements. I'm also for measurements for our audio acuity as well as eyesight.
Then, matching speakers to our ears, just as corrective lenses are matched to our eyes.

I beg to differ.

let's say my hearing is xyz.
let's say I go to abc live concert.
what my brain hears is xyzabc.

No... It would hear a flawed version of concert ABC.
Just as our eyes see flawed blurry letters on a perfectly good eye chart.

let's say i've got a perfect speaker/room/recording (not that it exists)...what my brain still hears is xyzabc.

Nope...it will still hear that perfect scenario in a flawed and imperfect way.

I don't buy that "we all hear differently"....

That's like saying, "I don't buy that we all see differently"
Were gonna have some trouble explaining all those people with prescription glasses and contacts.

 

[Irvrobinson]

Don't forget, ;;your;; Salon2s use an elliptical waveguide on the tweeter as well, which makes you a "horn guy". It matches the directivity index of the 1" tweeter to the 4" midrange. That it boosts forward radiated sound at the bottom of the passband (and thus max SPL) is a bonus but not the primary design criteria AFAICT.

I knew that was a waveguide, but it's so shallow I never thought of it as a variant of a horn. I suppose to a 4KHz sound wave it is deep!

 

[AcuDefTechGuy]

I played it on B & W 800D with 400 watt per channel Macs. I could may be just about get to the spl I heard in the Church. The perspective was moderately well preserved. The midrange driver was starting to sound stressed, and the En Chamarde trumpets had a little too much reed over the bell of the pipe.

And how loud was the sound in the church?

Can people in the church tolerate 95dBA?

 

[GranteedEV]

I have to preface this by saying I'm all for speaker measurements. I'm also for measurements for our audio acuity as well as eyesight.
Then, matching speakers to our ears, just as corrective lenses are matched to our eyes.

Bad analogy. It's more like having a TV, and playing around with the calibration settings for your idea of what's white, what's green, what's red, what's black, even if the rest of your family has to sit through green whites, exaggerated skin tones, and gray blacks. Why not calibrate the TV accurately so the skin tones look on TV how they look in real life? Because your vision sucks??

No... It would hear a flawed version of concert ABC.
Just as our eyes see flawed blurry letters on a perfectly good eye chart.

Speakers are not hearing aids though. Hearing aids are hearing aids. Glasses are glasses and TVs are TVs.

Nope...it will still hear that perfect scenario in a flawed and imperfect way.

If your brain can't differentiate between the live concert and the speaker then there is nothing flawed or imperfect about it.

That's like saying, "I don't buy that we all see differently"
Were gonna have some trouble explaining all those people with prescription glasses and contacts.

We don't "see differently". You don't see a square when I see a triangle. You don't see black when I see white. You might not see as adequately as me, you might not be legally allowed to drive a car without glasses on. That doesn't mean there's a car that slams the brakes for you when you fail to see a pedestrian crossing the street, because it knows you can't see when you don't have glasses on.

I don't mean to sound unsympathetic. If someone wants to manually EQ their speaker so it sounds clearer to their ears then that's a choice they should have, but the rest of their family might be the ones getting screwed over. My maternal grandma, God bless her, is virtually deaf... we have to yell into her hearing aids just to have a conversation. It would be unrealistic to have custom speakers for her hearing curve alone. It's sad but true.