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In Reply to: RE: In the same issue, at under half the price . . . posted by Brian H P on February 08, 2023 at 13:34:48
Or, Gib mir ein brechen.
Or, give me a break.
Wireless?
Yeah, sure.
And what is the diameter of the KEF's DSP bottleneck? And what is the jitter number?
Oy.
If somebody has spent $10,000 and up for a DAC, why does she want a digital bottleneck inside the loudspeaker?
KEF uses its corporate piggy bank to make sound that is... OK; but almost always: cost-compromised.
I have not heard the Alta Adam. But that tweeter is, unless I am mistaken, a Fountek NeoCD2.0, a driver I am familiar with. In the US, it costs about $160 each.
Fountek's NeoCD3.0 is found, with a waveguide by Falcon Acoustics, in Falcon's $27,000 "statement" loudspeaker.
So, two NeoCD2.0s cost the loudspeaker builder $320 plus shipping, and you multiply that by 500% to cost out the product at retail, and the tweeter part of the retail load is at least $1600.
The KEF stuff that Amazon ships out by the container-load is great bang for the buck, but... the people who spend the money for much better tweeters are not fooling themselves.
It's the people who believe that sound doesn't get any better than what KEF sells for $1600 who are fooling themselves.
Now, not having heard the speaker itself, I can't speak for the implementation, but the raw materials are unquestionably there.
OF COURSE, speaking only for myself.
ciao,
john
Follow Ups:
Great drivers are important but given the choice between great drivers and a good crossover versus good drivers and a great crossover I'd choose the latter.
The linked-to 5" SB Acoustics Satori TeXtreme woofer-mid ($273.10/each), in its write-up, states:
"This unit features smooth frequency response and low inductance allowing for minimal effort in network design."
I was chatting with a loudspeaker-industry guy whose company OEMs the drivers for a nine-channel autosound system in a car costing more than $3 million, and he said one reason his coaxial tweeter-mid driver was chosen as the workhorse for that system was that the total crossover-parts count for tweeter and mid together was three parts; two capacitors and one coil.
BTW, as an old disciple of Bud Fried, I am not sticking up for an undamped transmission line; but I am saying that Alta Audio chose a very fine tweeter.
john
I basically agree but assuming but I'd still prefer a good driver and superior crossover. But it has to be a good, less expensive driver. A great crossover can't make up for even so so drivers and indeed given the cost of good crossovers would be a waste of money.
. . . need not always correspond with more expensive. Back in the day, before Tymphany took over (and IMO ruined) Danish Sound Technologies, Vifa and Peerless offered a number of reasonably priced, excellent sounding poly-cone drivers with those characteristics. Their inductive impedance rise could be easily flattened with a Zobel, making first or second order lowpass filtration a breeze. Same story, at a step up in price, with many of the then-available drivers from Audax, Focal, Morel, and SEAS.
Conversely, some very expensive hard cone drivers (like the currently available SEAS magnesium and aluminum cones) ring like a fire alarm a little over an octave into their optimal stop band, making lowpass filtration a total bitch. You can use an ultra-steep elliptical filter like Joseph Audio, or aggressive notch filtration, to suppress the breakup peak(s), either way at the cost of considerably greater crossover complexity.
That Satori unit you linked to does look like a lovely driver, and should be way easy to work with. The Fountek ribbon should be a great match. Its on-axis response (see Vance Dickason's linked measurements) is a bit uneven, and in fact looks very much like JA's measurement of the Alta speaker's treble. The response blump between approx. 1 and 2kHz is an artifact of the shallow horn loading and can be suppressed in the crossover (probably around 4th order electrical, just to be safe), while higher up the response flattens out nicely at 30 degrees off axis. I'd be eager to read about your finished project using those drivers.
Supposedly, the NeoCD3.0 is an "homage" to the old Decca ribbons.
The above is the graph from the factory data sheet. (Full .pdf at link)
It's a very nice smooth driver.
BTW, Rockport is supposedly making their own TPCD (Thin Ply Carbon Diaphragm) complete drivers, but I don't know if they are getting the cones from the audio division of Oxeon. The SB Satori is for the rest of us... and I do believe they get their cones from Sweden.
I must say that between the Satori TeXtreme woofers and Purifi's "Hair-Scrunchi" woofers, it's an exciting time to be messing around with loudspeaker design!
john
Just from the graph, it looks like a 4th order electrical filter down -6dB at 2.5 to 3kHz would get you a nice 3rd order acoustical rolloff.
True ribbons are fragile, and generally need steep filters to avoid damaging overexcursions at the bottom of their passband. Years ago, a NY importer called Zalytron carried some Raven brand true ribbons from France, and recommended 6th order (or steeper!) highpass filters.
For the latest go-round, I took the woofer off the crossover and connected it directly to the amplifier. Before that, I had the tweeter level up +2dB because of the wide trough in the FR.
So now the woofer is running flat, but I think that +1dB would be better. Please keep in mind that when JA measured Harbeth's P3ESR, it was +1 in the treble.
One thing I like about the idea of letting the woofer run wild is that one can re-dedicate that money to nicer capacitors on the tweeter.
BTW, Fountek ribbons are "reinforced," which I believe is some kind of film lamination process. So, their ribbons are not only more affordable, they are more robust.
Thanks for your interest,
john
Edits: 02/17/23
I'd analyze distortion on that for sure. Ribbons tend to have high distortion at lower frequencies -- highly audible distortion. Not controlling the top end of the woofer can result in something nasty if it's just left to fend for itself.
Not saying that would happen -- but it certainly could.
Doug
SoundStage!
The fellows at ASR might even approve!
The baffle step compensation looks well dialed in, and the slight irregularities above crossover should level out at 15 to 30 degrees off axis. The lift above 8kHz should contribute some sparkle and shimmer high up, without excessive brightness.
I've never worked with true ribbon drivers (fragile! expensive! scary!), but have done a couple of builds with the Bohlender Graebner NEO 3 PDR magnetic planar tweets, which actually have a very similar response curve to your Fountek ribbons. Their superiority to a good dome lies mostly in their "open and airy" character in the top octave.
Wish it were so. I've rarely seen drivers without ringing that roll off where you want them. It's mainly the amount of ringing and how high ib frequency they ring. I will admit the Dynaco A25 driver seemed to be one good example as does the Madisound A26 woofer. And I recall listening to a Melos prototype speaker decades ago with a paper 8" Dynaudio driver where accidentally the crossover wasn't hooked up and it just sounded like a slightly dark speaker. But if you can find honest curves from good manufacturers I'd be surprised if you found anywhere even close to 1 in 20 non-ringing drivers.
And I recall falling in love with the SEAS 4.5" Nextel driver that had a beautiful curve. There's a later version with better magnet structure and edge coating to dampen cone resonances that Troels Graveson, A prolific and talented kit designer for those of you who don't know, prefers to the earlier version and it seems to be more resonant than the earlier version. Who knows?
Indeed, ribbons can make nice high-frequency drivers, but they can make really poor upper-midrange drivers. It's all about the range it's used in.
We measure distortion and, over the years, I'd noticed that most ribbons distortion badly under 3kHz. Makes the sound hard and edgy. Some people confuse the sound with the speaker being more revealing, but it's not at all -- it's distortion.
In a three-way someone SHOULD be able to cross over high end. But it's an issue if not.
Doug
When I went from one prototype cabinet size and woofer to the next iteration, I actually bumped the crossover point of the Fountek NeoCD3.0 ribbon (the shorter, 3-inch sibling of the larger one Alta uses) from 2,500Hz to 3,000Hz, because I loved the upper reaches of the wonderful Eton Kevlar trilaminate woofer.
I then took the woofer off the crossover and ran it "wild," directly connected to the amp.
For whatever you can glean from an iPhone video posted to YouTube, that is what the link is to.
And in any event you can be entranced by Kate St. John's sultry voice, declaiming verses by Tennyson, believe it or not!
john
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