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Zilch

The Goals for an "Ideal Loudspeaker"

175 posts in this topic

Help me, now, with this hypothetical:

1) Someone paid $230 for a pair of AR2ax 35 years ago,

2) They haven't heard anything they like better in the intervening years,

3) Having minimal interest in doing so, they haven't gone out of their way to ascertain whether or not such even exists,

4) They have zero motivation or inclination to experiment on their own,

5) If someone were to bring an example to their door (or send a limo to take them elsewhere to audition one), they'd listen,

6) But ONLY if it looked vintage, had a wood finish other than ebony, and natural fiber grilles.

In fact, their only interest in modern technology and design, or knowledge of the 40-year-ago equivalent thereof, for that matter, relates specifically to mitigating any concern which might arise as to the likelihood of their status quo being sustainable; their experience affirms the "ideal" loudspeakers are the ones they've have had since 1975.

I envision the archetypal enthusiast for whom there would be no greater pleasure to be found in audio than a brand-new exact replacement AR3a tweeter for $15 or less with a 40-year warranty.

[Edit: OOPS, our friendly forum moderator told us we're not s'posed to talk about each other here; perhaps we should get back on topic.... :) ]

Thank you for spelling it all out. I was wondering if it was just me, but hey this is the Internet!

Gene, this really should move to a cloning thread because this thread was doing very well, and it will be

easier to find as a cloning thread.

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If you know someone near me who has a pair I can listen to, I'm game. But as I keep telling you, I don't build audio gear or "order" things I've just read about, I buy things I like that are all put together after I hear them. For a bunch of people hanging out on an audio forum, some of you don't seem to listen very well. :)

Contact Geddes, he will let you know if he has a customer in your area that is willing to demo

them. I am fairly certain that Geddes sells them assembled. I don't think they exactly fit your

interests since they require subs, but they are certainly worth hearing.

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Thank you for spelling it all out. I was wondering if it was just me, but hey this is the Internet!

Gene, this really should move to a cloning thread because this thread was doing very well, and it will be

easier to find as a cloning thread.

That's ok, if you all don't really want to hear everyone's goals for an "ideal" loudspeaker I'll just leave you all alone and not talk about mine anymore.

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The performance of Geddes's waveguides and the Nathan product have been documented by others, and eWaves A/B's against Geddes products. Earl admits that the Nathan waveguide is too small, and himself suggests that his 12" Abbey is a superior design. He has recently "adjusted" the performance of his entire line.

Is the A/B comparison documented online somewhere?

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That's ok, if you all don't really want to hear everyone's goals for an "ideal" loudspeaker I'll just leave you all alone and not talk about mine anymore.

Do we correctly understand that your goals comprise a replication of classic AR3a performance, without definition of what that is, or at least, something very similar?

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Do we correctly understand that your goals comprise a replication of classic AR3a performance, without definition of what that is, or at least, something very similar?

More specifically, the ability to replicate that performance when desired, yes. I don't mind at all if it can also do something else, so it could certainly include settings to make people who prefer vintage JBLs or new Geddes designs happy as well. Lacking the technical background to be able to say what defines performance, I'm not saying the speaker needs or doesn't need CD, wide dispersion, room interaction or any of the other things people here frequently argue about, and I'm not wedded to a particular technology, so if someone thinks they can get there using ported woofers, line arrays, electrostatic panels or waveguides, go for it. I'm just saying what my "ideal speaker" would need to be able to do for me when it's set up in my living room. In all the discussion of "ideal speaker" design goals am not seeing anybody (except for Pete, who says he can clone the sound of any speaker but doesn't say the "ideal" speaker should be able to do that) talk about how the darn thing might actually sound.

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When Ken suggests "engagement" as opposed to "neutrality," by one view (which may not be what he means), that suggests a level of specialization (or perhaps versatility via modeling) not unlike the present condition of L100 vs. AR3a, as example; neither is neutral, with each being artificial in its own uniquely engaging way.

Does this imply an inherent mutual exclusivity, or can such disparate performance capabilities be built into a single "ideal" design? Key to accomplishing this is knowing (and understanding) what characteristics distinguish one from another.... :)

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When Ken suggests "engagement" as opposed to "neutrality," by one view (which may not be what he means), that suggests a level of specialization (or perhaps versatility via modeling) not unlike the present condition of L100 vs. AR3a, as example; neither is neutral, with each being artificial in its own uniquely engaging way.

Does this imply an inherent mutual exclusivity, or can such disparate performance capabilities be built into a single "ideal" design? Key to accomplishing this is knowing (and understanding) what characteristics distinguish one from another.... :)

That would depend on what all the experts conclude defines "performance," or maybe "out of box experience" would be a better term. If all it turns out to be is on-axis frequency response, then a printed sheet of curves to enter into my EQ would be enough for me, but since an awful lot of modern gear doesn't come with EPLs and a lot of modern listeners act as if equalizers have a smell, something passive on the speaker itself would probably be better. If it's something else, you'd have to come up with a scheme for varying that parameter. Don't know how to create variable directivity or dispersion; maybe some kind of modular user-swappable driver design?

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More specifically, the ability to replicate that performance when desired, yes. I don't mind at all if it can also do something else, so it could certainly include settings to make people who prefer vintage JBLs or new Geddes designs happy as well. Lacking the technical background to be able to say what defines performance, I'm not saying the speaker needs or doesn't need CD, wide dispersion, room interaction or any of the other things people here frequently argue about, and I'm not wedded to a particular technology, so if someone thinks they can get there using ported woofers, line arrays, electrostatic panels or waveguides, go for it. I'm just saying what my "ideal speaker" would need to be able to do for me when it's set up in my living room. In all the discussion of "ideal speaker" design goals am not seeing anybody (except for Pete, who says he can clone the sound of any speaker but doesn't say the "ideal" speaker should be able to do that) talk about how the darn thing might actually sound.

Don't think I ever said any speaker. I can clone most designs that do not use

unusual drivers. I have done several.

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Don't think I ever said any speaker. I can clone most designs that do not use

unusual drivers. I have done several.

So would AR's old drivers be on your list of unusual and unclone-able drivers...?

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So would AR's old drivers be on your list of unusual and unclone-able drivers...?

You can find my response here, because I don't see this as having anything to do with an "Ideal Loudspeaker":

http://www.classicspeakerpages.net/IP.Boar...?showtopic=5921

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You can find my response here, because I don't see this as having anything to do with an "Ideal Loudspeaker":

http://www.classicspeakerpages.net/IP.Boar...?showtopic=5921

Fair enough, I'll just post there and assume that whatever this "ideal speaker" turns out to be it probably won't appeal to me.

Keep in mind, though, that even here in The Kitchen, discussions need to involve classic speakers to be on topic (check the subtitle on the forum and email Mark if you have any questions on that). If it's not your intent to eventually make some link between that "ideal speaker" and the classics this site is devoted to, you may want to consider finding some other place to have this.

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Keep in mind, though, that even here in The Kitchen, discussions need to involve classic speakers to be on topic (check the subtitle on the forum and email Mark if you have any questions on that). If it's not your intent to eventually make some link between that "ideal speaker" and the classics this site is devoted to, you may want to consider finding some other place to have this.

I have already made the link, in Post #1 of this thread -- constant directivity, a matter of considerable discussion throughout threads here in The Kitchen.

["Job One," in my view.... :) ]

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I have already made the link, in Post #1 of this thread -- constant directivity, a matter of considerable discussion throughout threads here in The Kitchen.

["Job One," in my view.... :) ]

Hmmm... still haven't heard a good argument for constant directivity in spite of asking twice. Now that we have pushed the cloning of vintage hardware off to another thread, maybe we can get back to the topic. Can anyone put down a spec for the ideal speaker, or justify the basic tenants?

"Necessary and sufficient criteria."

David

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Hmmm... still haven't heard a good argument for constant directivity in spite of asking twice. Now that we have pushed the cloning of vintage hardware off to another thread, maybe we can get back to the topic. Can anyone put down a spec for the ideal speaker, or justify the basic tenants?

"Necessary and sufficient criteria."

How about goals that aren't necessarily sonic, like being movable by one person without the use of a lift truck, impedance that is compatible with a wider range of electronics, etc.?

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Can anyone put down a spec for the ideal speaker, or justify the basic tenants?

"Necessary and sufficient" criteria.

Conceptually, in keeping with Ken's original framing of the topic, I'm trying to formulate and posit goals as separate from how they might be accomplished.

Thus far, I have suggested two goals:

1) Room independent - adaptable to a variety of typical listening spaces.

2) Musical genre independent - competently renders any and all of them.

How about goals that aren't necessarily sonic, like being movable by one person without the use of a lift truck, impedance that is compatible with a wider range of electronics, etc.?

I believe equipment independence should be added to the list of goals, yes.

Do others agree?

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The hard part of defining the ideal speaker is seperating the features that seem like a good idea from those that are requirements. Here is my list.

An Ideal speaker has:

Very flat on-axis response

Very smooth on axis response

Very flat and smooth response through any likely listening window

Smooth and resonance free power response, but of no particular curve

Holes in the power response are acceptable but peaks are not

Generally rising directivity (non flat d.i.)

Generally wide dispersion

Wide bandwidth with a -10dB cutoff below 35 Hz

Interfaces well with the room, gives a smooth in-room curve below 200Hz

Adequately low distortion. Low AM distortion with high woofer excursion

“Ideals” that haven’t been proven to be beneficial:

Flat phase response

Response extended beyond the audible range

Extremely low distortion

Low order or particularly high order crossovers

Any particular in-room curve, above 200 Hz

Any particular spectral response of reflections

High tech. materials

Exotic transducer types

Exotic cabinet types

Overly high or overly low directivty

Things that have been proven to be detrimental:

Flat power response

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How wide would "generally wide" be as dispersion goes, and how would that compare with some things we're familiar with (for example, the speaker we're not talking about cloning, the speakers you used to produce at Snell and Zilch's favorite waveguide)?

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How wide would "generally wide" be as dispersion goes, and how would that compare with some things we're familiar with (for example, the speaker we're not talking about cloning, the speakers you used to produce at Snell and Zilch's favorite waveguide)?

The highest ranked systems in Toole's studies average a directivity index of about 6dB from 500 to 7,000 Hz. The typical CD waveguide is probably a d.i. of 9 or 10dB (say a 100 by 100 degree horn). Snell systems were totally conventional in directivity except the XA series that used symetrical arrays (di'Appolito) with about 3dB higher directivity than the usual driver on a flat baffle. (Adding some midrange vertical directivity is a good thing regarding floor bounce effects.)

I would aim for a 120 to 150 degree wide dispersion lateral and 60 to 90 vertical. (These are the -6 falloff points) Aim for response perfection in a +-30 degree window. You should hear the same direct response "anywhere on the couch".

Constant directivity waveguides have a benefit in that they may have very even response in the listening window, although the Geddes model seems to have some problems on axis. For home use I would make them wider dispersing than they typically are. A flat baffle with well radiused corners may be the best type of CD waveguide!

David

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This was a typical Snell product. The array was used for theater products and home products (XA90 and XA75). the tweeter has a waveguide 150 degrees wide (if I recall correctly).

post-102584-1273145637.jpg

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Constant directivity waveguides have a benefit in that they may have very even response in the listening window ...

Yah, we've kinda got a 60° x 30° listening window covered:

http://www.jblpro.com/catalog/support/getf...3&docid=665

And can approach your 120° and DI = 6 spec, as well:

http://www.jblpro.com/catalog/support/getf...&docid=1079

Though I'd argue against that.

...although the Geddes model seems to have some problems on axis.

Geddes maintains it's indicative of perfection. A perfect axisymmetric waveguide of necessity has interference on-axis.

His answer? Don't listen to Geddes speakers on axis, rather, use extreme toe-in, 45°, and listen at 22.5°.

We have suggested to him that asymmetric may be provide a better solution, although his early elliptical exhibited the same issue. He gives everybody a protracted "Why mess with perfection" argument, but says he'll try that.

[Problem is, he can't make the mold himself in his garage.... :) ]

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