Beyond the Ariel

Lynn,
Not to start an argument but what you have just posted seems to be the major reason that besides a few diehard audiophiles the vacuum tube industry is basically dead. It isn't even that it uses vacuum tubes but the very basic limitation of non feedback topology. We all know that even high efficiency speakers are a rare breed today, size matters to the masses and larger high efficiency speakers just don't fit the bill anymore. So you are in very rarefied company today. Even here in the diy side of things you are a very small minority. Personally i have no interest in class-A operation, it just has to limited a use outside of very few speakers today. Yes I could use something like that with the Altec speakers I have sitting in a large room but even those are so rare today that most people don't even realize that they are speakers.

I commend you on keeping up the good fight, I just think you have little company to keep in this endeavor. I've heard some of the expensive SE amplifiers with 7 watts output and perhaps a bit more and wouldn't give a plugged nickel for that kind of power. There is no way that is going to drive even my high efficiency speakers to any kind of real dynamic level without falling on its face. I've used them to make the audiophiles happy at the old Stereophile shows but strictly to power the high end with compression drivers where that low power was more than enough. I can't imagine using them for anything beyond this. It seems even 50 years ago that is why feedback tube amplifiers were developed, there just isn't a market for anything less. You are part of a very dying breed, I can only imagine what your amplifier would cost on the open market? One of the reasons that the high end audio industry is disappearing today, it is almost a non entity.

Since I have to market into this newer world of consumers I can't even think about a vacuum tube, it is not possible. I have to work with SS and digital make it as good as it can be. anything less than that is just commercial suicide.
 
Last notice: Gary Dahl will have his whole system at the Sound DIY Meet on Mercer Island this next Saturday! I'm mistaken, actually his TT and Phono amp won't be there, however the rest of his system will be. If you live anywhere near Seattle you may want to show up. BTW: Free Attendance and Parking !!

See the Puget Sound DIY Meet posting for more details and directions.

Best Regards,
Terry
 
Well summarized Kindhornman. Still, it's nice to follow those who are willing to go the extra mile(s) to satisfy their own tastes, even though few of us have that level of commitment in time or expense. I learn as an observer.

One other common and irreversible trend, is that music now is supplied digitally - unless one is willing to live with a much smaller choice. In fact essentially all music is now recorded and especially processed in the digital domain. That being the case, there is no quality loss in a quality approach to using digital tools in the playback domain. I've chosen that route because I don't have the patience to learn everything that's required to implement a complete analog crossover system. With a DEQX (not DEQ), I can measure and let the system correct amplitude and phase errors, and level match the drivers across the system's full range. Even here the learning curve is fairly steep. But once mastered, one can make rapid changes and make specific profiles for specific amp/driver combinations that account for amp and speaker impedance. But the learning curve and the added complexity for each added amp, and the added clutter of wiring, makes this approach still a decidedly minority one.

Sheldon
 
And therein lies the question. What type of directivity or dispersion a person prefers. Some want extremely narrow dispersion and the head in a vice sweet spot, some want a wider window,

I think it's a mistake to think that directivity is just personal taste. The more constant directivity, the more preferred the sound.
 
kindhornman said:
but the very basic limitation of non feedback topology
Has been shown to be a non-issue. Have you not even bothered to read the measured (not designed) performance of Lynn's amplifiers?

I guess Nelson Pass is wrong too.

...That being the case, there is no quality loss in a quality approach to using digital tools in the playback domain.

Even if I concurred, I can barely afford two channels of decent DAC and now you'd like me to purchase six or eight?

And then one gets to sort the wheat from the chaff in the digital domain (given that we're still suffering it's-digital-therefore-it-is-perfect fan-boy-ism in the press) when designing the cross overs.

For me the whole point of building the Ariel was to avoid designing the crossover - I knew enough about speaker design to know what I had neither the time nor the experience to do well.
 
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thoglette,
I have nothing against Lynn's amplifier, it is a purpose built design for his application. As he just stated it has limited power, that is a problem for many. If it fill your need and you think you can reproduce it go ahead. I personally would never build the design as stated, it just isn't something that I want. I can build a dynamic driver and compression driver system, I have done it many times. I just have different desires and different opinions about how I would do that. If I wanted to build an all horn loaded system I could do that also. I am traveling a different road these days. And no I would not build a non-feedback amplifier, 1ever. That doesn't mean others can't do that, it is a very specific type of design for a specific use.

ps. Don't forget that Lynn is using a digital front end.
 
Kindhornman, as much as I respect your knowledge and contribution, I think commercial perspective is clouding your view on the hobby. AFAIK Lynn is doing it just for himself, because he thinks it's the right way to audio bliss and he is sharing his experience to help others (and to brag a little bit ;) )
I enjoy reading his posts and I'm sure it's not just me.
 
It seems even 50 years ago that is why feedback tube amplifiers were developed, there just isn't a market for anything less. You are part of a very dying breed, I can only imagine what your amplifier would cost on the open market? One of the reasons that the high end audio industry is disappearing today, it is almost a nonentity.

Since I have to market into this newer world of consumers I can't even think about a vacuum tube, it is not possible. I have to work with SS and digital make it as good as it can be. anything less than that is just commercial suicide.

You might be surprised to learn that Audio Note has sold more than 100 Ongaku amplifiers at the modest price of $87,000 each. The Ongaku is not the most expensive Audio Note product; I think they top out around $150,000, and yes, people buy them. I know a guy who makes tonearms and sells them for $23,000 apiece. Not the turntable, not the cartridge, but just a tonearm. He has a waiting list of customers. I am not making this up; it's real.

Lesson learned? The world capitalist system creates people with an unimaginable amount of wealth, and there are more of them around than you might think. Heck, for that matter, Apple iPhones have a production cost around $180, and they sell the same phones for $700 each, a nice fat profit of $500 per phone. Multiply by tens of millions and you get a company with a market capitalization approaching a trillion dollars. Samsung is basically doing the same thing with their premium smartphone.

The right people have lots of money, and are quite happy paying serious cash for what they want. As long as we have a capitalist system, this will continue to be true. Did expensive things get made in Roman times? Yes. Did the landed aristocracy buy expensive things in the Middle Ages? Yes. Did English industrialists buy expensive toys in the Victorian era? Yes. Are we in a Gilded Age right now? Yes.

I disagree that I am "part of a very dying breed". Chinese (and Asian) high-end audio are nuts about tube amps, and they make a ****load of DHT vacuum tubes, with new types coming out each year. Did you know that LP pressing plants worldwide are operating at full capacity and LP sales are growing each year, while CD sales decline?

People who are financially stretched are stealing music off the Internet and playing it on no-name Chinese electronics, while the wealthy and near-wealthy indulge their taste in non-mass-produced artisan products (vacuum-tube amps, LPs, handmade this and that). The world market is stretching in both directions, at the top and the bottom.

It's the middle that's getting hollowed out. Going further, I'm not sure there is any solid market for "value" high-end audio. The vast majority of people are happy listening to music on their phones and laptops, and think of a battery-powered Bluetooth loudspeaker as a high-end purchase. A $5,000 music system is inconceivable ... that's ten times the price of a B*** radio, and why would anyone spend more than what a B*** costs?
 
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I think it's a mistake to think that directivity is just personal taste. The more constant directivity, the more preferred the sound.

Tell that to those who want an omnidirectional speaker. It is definitely a personal preference.

err, omnidirectional speakers are constant directivity. :rolleyes:

And no, it's not a personal preference. When reflections have a different tonal balance to the direct sound, it is less preferred. Hardly surprising!
 
You really need to sum together all the losses. I have only simplistically stated the physical phenomena going on. It is not contrary to the physics. If you have data, demonstrate that on an equal playing field that a CD is better at low level detail than a comparable dome tweeter, from what is available.

You cannot really argue away the problem of potentially greater low level information multiple losses from a CD unless you engineer to more than compensate for the losses. You can start to compensate by using huge magnets on the CD and many other things. In many applications it does not matter.

My belief is the best dome available will exceed any CD available on published impulse testing results. And any overshoot and ringing is a loss, ie distortion. Put a good Be dome 1" tweeter up against any CD. If you can find an available 1" CD that matches the current SEAS and Scanspeak domes then I would be interested.

Both CD and direct drivers have their place and both can be used on wave guides and horns. Each wins in its own arena, which may be live music repro, PA reinforcement and home hifi, and it can be neck and neck i.e no outright winner across all applications. Dome drivers withoutthe phase plug are far easier to design and to maximise their SQ performance.

I still like both options and will carry on reviewing the CD possibilities as the new wave of drivers especially with new diaphragm/dome materials roll out

I'd say a 1,5-2" exit comp driver with fully aluminum construction & phase coherent aluminum phase plug (do not accept plastic radiator, phase plugs or construction) loaded with a 4" beryllium dome, is one of the most uncolored and best sounding mid and tweeter I have listened to. The SQ stays virtually the same no matter how loud you play and clarity with very complex and crowded signals like metal music is quite wonderful.
 
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Sorry about the long rant on the previous page, but I think it's a mistake to let the market tell us what we should and shouldn't do. Markets are capricious, despite the claims of the Chicago School of economists, and not as rational as theory says they are. The madness in the 2000~2008 period should draw a line under the "rational" market theory.

Another way of saying this is that products are "worth" what a market says they are ... and markets can be irrational for long periods of time. Not talking about inconsequential things like high-end audio, but decisions made in the board-rooms of the largest corporations in the world.

If the best-informed economists in the world got it so spectacularly wrong for more than a decade, why blame the innocent consumer shopping at Costco ... or the potential buyer at the Rocky Mountain Audio Festival, lusting for the $20,000 amplifier? People buy what they want, when they want, for reasons that are not well understood.
 
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err, omnidirectional speakers are constant directivity. :rolleyes:

And no, it's not a personal preference. When reflections have a different tonal balance to the direct sound, it is less preferred. Hardly surprising!

Yes, constant directivity is preferred as long as no compromise or trade off is taken when enforcing the constant directivity.

When there is a trade off, it is then a preference to decide which one and by how much to trade.

For small room and hence nearfield listening, I cannot make a tweeter WG that sound more preferred than normal tweeter [so smoother directivity is not my preference]. Haven't heard a CD or horn that satisfy me in term of sound purity. Haven't heard tube amp that I want to own either... That's preference, right?
 
Hey Jay, what one person likes or doesn't like in casual uncontrolled listening tests is swamped in 'post-sonic bias' and is of no interest (has no application) to anyone except themselves, and so has no place in a public conversation other than to waste space or constitute an impromptu poll.

And, there is no way that I am going to twist a point about constant directivity into a 'cone vs horn' dichotomy.
 
Hey Jay, what one person likes or doesn't like in casual uncontrolled listening tests is swamped in 'post-sonic bias' and is of no interest (has no application) to anyone except themselves, and so has no place in a public conversation other than to waste space or constitute an impromptu poll.

And, there is no way that I am going to twist a point about constant directivity into a 'cone vs horn' dichotomy.

My point was that the "preference" Kindhornman was talking about could be related with the trade off taken to ensure the constant directivity.

So, I agree with him that it is a preference, and I also agree with you that it is not a preference. It is always related to people ability to see the big picture.
 
A reasonably well designed speaker is going to handle all kinds of music equally well. What I was testing small speakers, effort was made to cut off low frequency which drive the drivers into nonlinear range resulting in horrible distortion. 40hz steep cutoff seemed to work optimally such that distortion becomes not so annoying. Also specifically tested some tracks from a bassist which had very high levels between 40Hz-60Hz, this seemed to work quite well.
 
As I said above, it doesn’t make sense to talk about turbulence micro or otherwise in conjunction with an oscillating motion. As Dr. Geddes correctly pointed out, vortices need time to develop. We’re not dealing with a linear flow at some velocity such as for example water in a pipe, where an obstruction in the stream can set up vortices. This is the propagation of oscillating motion in air molecules and ‘disturbances’ here are called diffraction waves. Micro-turbulence? That’s called Brownian motion of the air particles and if it would ever be a problem with CD’s it would certainly be so with dome tweeters in equal measure - just as is the case with diffraction.

Furthermore, If turbulence could be set up, it would have to be supported inside the space of the compression chamber and inside the phase plug, whose dimensions are in the range of 1 to 2 mm. The wave length at 5 KHz is 69 mm. What effect would a 1 mm vortex have to a wave length 69 times larger? I’ll let you figure that one out. [hint: a wavelength of 1 mm is 344 KHz]

You mention losses into heat in CD’s. This is at best an unsubstantiated claim. Collisions of air molecules with hard surfaces inside the driver are elastic and there are no lossy/absorptive materials to turn motion into heat. And please don’t come back with claims about skin friction and such, since again this is not linear flow and there aren’t any shear forces involved.

Let’s talk about wasted energy in CD’s. This is truly erroneous! Here, we have a driver type that on average is 30% efficient. IOW It turns 30% of the electrical energy into acoustical energy. The dome tweeter is at best 3% efficient. Do you really want to talk about losses and wasted energy in this regard?! – really?!!! :scratch1:

As for your claim on the voice coil heating losses, here again the thermal capacity of the CD’s coil, is an order of magnitude greater than that of a dome – after all, they’re built to support very high SPL’s and the accompanying heat issues. There was a thread here a few years back started by Dr. Geddes on the perception of dynamics in loudspeakers. There was much discussion on the effects of heat in voice coils and such. I suggest you find it and read it, it’s quite educational.

It seems you like dome tweeters. No one can argue with your perception. Enjoying what you like and thinking that it’s the best for you is one thing. Here however, you’re trying to reconcile your belief in the superiority of the dome with unsubstantiated claims in physics that frankly don’t make much sense. When your postulations are confronted, you claim ‘simplistic denial’. Unfortunately and as was said earlier, the burden of proof lies with the claim and you’ve made quite a few of them. I don’t mean to be confrontational and there’s no offense intended, but you don’t seem to have a good grasp of physics, at least not on this topic. Had you simply stated that domes sound better to you… well, what could I or anyone else say to that? Not much indeed!

Take care and enjoy the music.

Look up Wikipaedia - Compression Driver

You will see the pulsing sound in the phase plug and throat from the CD animation. It shows the diaphragm moving in and out. So with the complex musical signal it will be following that within the air within the small phase plug holes or slots, moving in and out to the diaphragm oscillations. This represents a turbulent flow of air to be repeatedly forced back and forth.

This does not happen with domes which can fairly linearly project straight out to our ears. So there must be prorate less losses. Jay and I as well as the fraternity have heard this perhaps for 40 years or more.

It does incur its own noise due to the motion back and forth with the diaphragm. With a 3" (75m) diaphragm with say 1mm stroke is 4.4mls i.e 4.4 cubic centimetres of air being thrust back and forth in the phase plug.

On high frequencies this will be naturally very fast incurring more frictional loss and sufferering higher degradation in the process. That also gets magnified by the efficiency of a CD. It is the main problem for CD operated at high levels. No free lunch

Ask Earl to explain it to you, and how CD's work. Take the phase plug out and it is a direct driver, and at least this phase plug issue vanish. How much does it matter. It matters to those of us that can hear it.

I hope this helps.
 
I'm not sure there is any solid market for "value" high-end audio.
Your post is really interesting.

Value high end: I'm sure exactly what that means but,
1. there is Say's Law which it seems only a few folk understand and it's that supply precedes demand.
2. the rich (and technical avant garde) are first adopters
3. the price then goes down because of competition
4. it takes a while for a consensus of what value (which is not exactly price) might be
5. competition in any market segment is ultimately on basis of providing best value
6. although the poor are always with us the numbers of rich folk are increasing at an accelerating rate
.................................

If we pretend for a moment that audio business is just starting out from scratch and ask ourselves, who in the business might well understand the 6 points outlined above and has modern scientific and engineering expertise and is providing very good value product?

A person who catches my attention in this regard, because of the comprehensiveness of his efforts, is Bruno Putzkey. Three companies he's involved with are Hypex (ncore amp modules and power supplies, very DIY friendly outfit), Moma Moma (high end amps, pres and DACs) and Grimm Audio (pro monitor speakers). This is the sort of outfit that's offering that value high end and it looks like they're going to be successful.

It's too late. Gotta go.