Which is precisely why "perception" is an unreliable metric to use in evaluating audio equipment. Its like using a rubber band to measure length. The "science" for amplifier output impedance is straightforward, but "perception" is pointless.
Nice post
Jerrod,
That was a very nice post, but leaves me wanting more information about your 2.1 system. What kind of ATM gets down to 500Hz ?
Please, that, and any more info you may provide. Details, man !
Thanks kindly !
Jerrod,
That was a very nice post, but leaves me wanting more information about your 2.1 system. What kind of ATM gets down to 500Hz ?
Please, that, and any more info you may provide. Details, man !
Thanks kindly !
It's a simple matter to add 1 to 1.5 ohms to the source impedance when modeling and measuring speaker systems intended for use with zero-feedback vacuum-tube amps. I did this for the Ariels 22 years ago, and it wasn't a new idea then. I knew people doing this back in the Seventies.
But it is certainly true that complex high-order crossover networks with tightly tuned notch filters are not a good match for these kinds of amplifiers. In addition to unexpected and unwanted frequency-response variations, non-feedback amps don't always like reactive loads. (Elliptical load-lines usually cause increases in harmonic and IM distortion well beyond the usual resistive-load measurements.)
There are also solid-state amps that get a little unstable when presented with highly reactive loads ... not all amp designers takes this into consideration when looking at Nyquist stability criteria. They should, but they don't. Stability is still a problem in some commercial amplifiers, unfortunately, and it's not a spec that appears on spec sheets.
On a more subtle level, reactive loads can also degrade Class A/B crossover transitions, depending on the feedback architecture, type of output topology, and value of emitter-resistor degeneration. Going further, unregulated power supplies can interact with the LF reactance peak(s) of woofers in closed and vented-box loudspeakers.
Speaker designers need to be explicit about what kinds of amplifiers are optimum for their designs, rather giving vague power recommendations. Since 99.99% of amplifiers sold are Class AB bipolar transistor amplifiers with high feedback ratios, the assumed type of amplifier is usually implicit.
But there is a small specialty market for weirdos who enjoy vacuum-tube amplifiers, just like the folks who like LP records, and there is a niche-market of speakers that complement these amplifiers.
But it is certainly true that complex high-order crossover networks with tightly tuned notch filters are not a good match for these kinds of amplifiers. In addition to unexpected and unwanted frequency-response variations, non-feedback amps don't always like reactive loads. (Elliptical load-lines usually cause increases in harmonic and IM distortion well beyond the usual resistive-load measurements.)
There are also solid-state amps that get a little unstable when presented with highly reactive loads ... not all amp designers takes this into consideration when looking at Nyquist stability criteria. They should, but they don't. Stability is still a problem in some commercial amplifiers, unfortunately, and it's not a spec that appears on spec sheets.
On a more subtle level, reactive loads can also degrade Class A/B crossover transitions, depending on the feedback architecture, type of output topology, and value of emitter-resistor degeneration. Going further, unregulated power supplies can interact with the LF reactance peak(s) of woofers in closed and vented-box loudspeakers.
Speaker designers need to be explicit about what kinds of amplifiers are optimum for their designs, rather giving vague power recommendations. Since 99.99% of amplifiers sold are Class AB bipolar transistor amplifiers with high feedback ratios, the assumed type of amplifier is usually implicit.
But there is a small specialty market for weirdos who enjoy vacuum-tube amplifiers, just like the folks who like LP records, and there is a niche-market of speakers that complement these amplifiers.
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Scientifically this is absolutely correct.
However I use my stereo setup in order to enjoy listening to music (mainly classical music).
What I'm looking for is the highest possible degree of sense of realism in music reproduction (while complete realism is unattainable, at any cost).
It's my experience that, generally speaking, measurements (those published by equipment manufacturers) have very little to do with my subjective impression of the degree of realism of music reproduction.
It's also my experience that the sense of degree of realism varies a lot between different individuals. I call it 'personal taste'.
Thus, I found that my own listening is the only way to ensure the degree of satisfaction I'll derive from any piece of audio gear. Published measurements results alone absolutely fail to ensure it. Some say that that my subjective listening impressions are unreliable due to phenomena like the placebo effect. I know from experience that this isn't so in my case. Even if it were so, the same phenomena influence my enjoyment while listening to music, so it doesn't matter, since this enjoyment is my only goal. I couldn't care less if this enjoyment is 'real' or 'imagined'.
Second best for me is the impressions of some other people with similar 'taste' to mine in music reproduction. This is why I'm so interested in what Linn Olson is doing.
To be honest, a little time ago, I built electronics only for technical reasons. When I try my first OTL (12B4 style of Futtermann, in 2006) at the suggestion of a friend who trusted his perception to guide the projects (and I almost refused his suggestion, because of my "sober knowledge in audio"), I was shocked ... it was a crash of concepts, and it was not only joy at that time; I was a BIG frustrated to know that my "traditional" concepts no longer applied to my perception, at least in a first superficial analysis.
I would really like to know all the answers that lead to certain perceptions ...
Hi,
Thanks for sharing.
Many would like to know it.
It seems to me that some elements are answered by those who are both well versed in electronics engineering and 'trust their ears', however, AFAIK, there aren't answers for everything.
I hold a firm inner conviction that there are solid scientific and engineering explanations to account for everything that impacts subjective listening experiences, however science and engineering are yet to find out many such explanations.
Thanks for sharing.
Many would like to know it.
It seems to me that some elements are answered by those who are both well versed in electronics engineering and 'trust their ears', however, AFAIK, there aren't answers for everything.
I hold a firm inner conviction that there are solid scientific and engineering explanations to account for everything that impacts subjective listening experiences, however science and engineering are yet to find out many such explanations.
There are most certainly solid explanations, and the vast majority are fairly straightforward. The worst offender is simply lack of attention to detail - the ignoring or only dealing in a perfunctory way with certain engineering aspects; my experience in tweaking relatively unambitious systems in straightforward ways, where I identify weaknesses in the totality of the system, and resolve them, has demonstrated this over and over again.
A "faulty" car and good mechanic is an apt analogy. The car may be a pig to drive, due to a simple, almost trivial fault somewhere - that mechanic finds the problem, fixes it in 10 minutes, and the car reverts to being highly pleasurable to be in, once again. The 'magic' was, that the mechanic knew where to look ...
.
A "faulty" car and good mechanic is an apt analogy. The car may be a pig to drive, due to a simple, almost trivial fault somewhere - that mechanic finds the problem, fixes it in 10 minutes, and the car reverts to being highly pleasurable to be in, once again. The 'magic' was, that the mechanic knew where to look ...
A decent analogy as long as you keep in mind that no mechanic can make a Ferrari out of a Ford (without basically starting over!) The basic design capabilities are imperative to maximum expected performance.
Just caught up with this thread again after 12k posts!
Have we a speaker design yet?
I still have the P13WH pair waiting!
Gary Dahl has a working pair of the new speakers; search this thread for all the build details. Look also at the "Island Speaker" thread next door; our friend "Vgeorge" has a version with the Inlow 135 Hz straight bass horn combined with the AH425 and Altect/GPA 288. Vgeorge has also kindly supplied a schematic for a passive crossover.
Martin Seddon of Azurahorn (Perth, Australia) has built a pair using 15" woofers combined with the AH425; contact him for more details. In a second system, Martin combined the AH425 with an Azura bass horn.
It was a couple of years ago, but Bjorn Kolbrek (the designer of the AH425) was using the AH425 with a folded bass horn of his own design. Gary Dahl is also in correspondence with a builder in Canada who has a version similar (but not identical) to his.
I'm still listening to my 22-year-old Ariels, but the Vifa midbass drivers are out of production, and I don't plan on re-designing them for contemporary drivers. My own version of the new speaker will most likely use a pair of GPA 416's per side, or if that falls through, a pair of TAD 1601's or AE TD15M's. The sheer performance of the Inlow 135 Hz straight bass horn is very attractive, but I don't think I have room for a pair of them.
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Why different interconnect cables, RCA plugs and sockets, XLR plugs and sockets, power cables, power plugs and sockets impacts sound.
There was a midbass version and a midrange-only version (short excursion); there may have been others for all I know. I selected the midbass version because of exceptional midrange performance, most notably, a freedom from HF resonance and peaking, so notch filters would not be required.
The 15" drivers mentioned in the previous post ... The Altec/GPA 416, TAD 1601, and AE TD15M all have well-behaved midrange regions as well, and are free of the usual HF crud in large-format drivers. That said, I wouldn't take them above 800 Hz, because they're not really full-range drivers.
Can you explain why running the GPA 416-8Bs up to 1kHz would not be wise? May plan was to build Gary Dahl’s 3 cu. ft sealed boxes for the 416s, which cut off their low end below 70Hz. My subs would take over below that. Then I’d bi-amp the 416’s with 2nd order Linkwitz filters at 1kHz with a pair of ESLs which go down to 950Hz. Would there still be serious midrange problems? If so, please elaborate before I throw any money in the wrong direction. Thanks.
There is no proof that they do. One cannot use science to explain differences that do not exist. One must always prove that differences actually exist before they can ever hope to find explanations for these differences.
As for 15" drivers with well-behaved midrange, I have not seen any better than this:
(Fostex W400A-HR: http://www.fostex.jp/wp/wp-content/uploads/2014/08/w400ahr.pdf)
A tad expensive, yes, but it seems to be pretty much state-of-the-art in terms of design, doesn't it?
Marco
P.S. I have made a follow-up post in the "Island speakers" thread to illustrate my point about the super-tweeter crossover options - just in case you'd missed it...
oltos,
The main problem with using the 416 or other 15" driver near 1000hz is "beaming". The wavelength of 950hz is 14.21" wide. This is also the frequency where the ear is most sensitive. The change at that crossover point between the electrostat and a sealed 15' driver box will be a large compromise IMHO. You would need to have your electrostatic speaker go down to around 500hz or so to get a better sounding midrange. If your electrostatic speaker can't make it that low then I would use a pro 10" ( or pair) like Beyma, B&C, or other similar type to cover the critical midrange.
The main problem with using the 416 or other 15" driver near 1000hz is "beaming". The wavelength of 950hz is 14.21" wide. This is also the frequency where the ear is most sensitive. The change at that crossover point between the electrostat and a sealed 15' driver box will be a large compromise IMHO. You would need to have your electrostatic speaker go down to around 500hz or so to get a better sounding midrange. If your electrostatic speaker can't make it that low then I would use a pro 10" ( or pair) like Beyma, B&C, or other similar type to cover the critical midrange.