Oh great, more speakers

[Charivari]

As long as the drivers are physically or electrically aligned so they behave as a single driver through the crossover region and the woofer cone is shaped so as not to cause cavity resonances, then yes, the coax driver is a good compromise, which is why I mentioned the KEF Uni-Q. Coax mounting seems such a good idea that I wonder why there aren't more of them. As it is, they seem to serve as exceptions that prove the rule.

Hijack mode: On

It would appear that the Tannoy DC design has managed to avoid these issues as you can see in this pic.

The tweeter horn through the pole piece is 1/2 wavelength long, iirc, at the crossover frequency (compression driver connected out of phase) so the tweeter and woofer cone are in phase. The cone acts as a continuation of the horn flare for the tweeter. There's a schematic for a time delay circuit floating around the net to make these drivers both phase and time aligned that I'm very tempted to incorporate into my Tannoys.

Anytime you complicate things you increase the chance that something will futz up, of course. Theoretically, a proper coax driver should vastly simplify xover design. Real world, the designer would still have to deal with the nonideal characteristics that accompany any passive crossover. Now-- to get hold of a good electronic xover with built-in variable delay... that might drop a train on a few problems..

Oh, I've very much been wanting to try this. Very much. Only problem is, as always, cost. Anyone out there with one of these crossovers they'd possibly be interested in trading for some speakers?

As you can see, this would be difficult, since the voice coil of the EMIT/M is mounted far forward of the voice coil for the woofer. But since there are separate drivers, I'd question the need for strict alignment anyway.

The Quantum 2s only use EMITs, but the dome mids and cone based midbass and woofers are supposedly physically in line, hence the addition of a phase ring for the woofer mount, to allow for proper phasing. The crossover is supposed to time align the drivers. All I know is that there's something in the sound that makes these seem to be more accurate than other, non-aligned speakers.

I get the idea behind time aligned but will this not only work if you are exactly the right distance from the speaker to make it all happen? :scratch2:

That's why you need to buy my future audiophile product, a special air spray that improves sound propagation in your listening room at only $572 per 12 oz can. The idea of phase aligning speakers is to make all the drivers launch the sound wave in the same phase and time aligning to make all the drivers launch the sound wave at the same time. This effect is there no matter how far the listener sits as it better reproduces how the sound leaves the instrument in the first place. It is a noticeable difference, but not too many vintage speakers had it in the first place. I'm uncertain about this, but I do believe Magnepans are phase aligned, but not time aligned. Am I right, Wualta?

- JP

 

[wualta]

Falling asleep now.. I'm (yawn) with kfa on this. A passive crossover with enough delay in it (uniform wrt frequency?) to compensate for two inches? Sounds downright dangerous. KEF at least got the tweeter small enough to tuck inside the woofer voice coil and poke its diaphragm out forward enough for mechanical alignment. Remember, it's not just phase. You could have a tweeter in Antarctica that's in phase with your woofer, but it certainly wouldn't be synchronized. If they ain't in sync, it's almost the same as separating them physically.

But the technical details aren't really the whole picture. If you like 'em, you like 'em, and ignore their faults because their virtues are glorious to a greater or lesser extent. What kfa has discovered is that there is a cardinal virtue in the simplicity of a single driver: clarity. And it's worth giving up a few things to gain that, just as we've been giving up clarity for frequency response extension and power handling. I think the current Ohm Walshes come closest to giving you the best of both worlds, but I'm willing to listen to reason.

 

[Charivari]

And so we return full circle back to time alignment; that is what you mean by "sync.". I've heard it does fantastic things with these older Tannoys and I hope someday to try it with mine, preferably after I get the cabinet resonances under control (shabby wood construction, they were a driver company, not a furniture maker). The AlNiCo slug shared by both the woofer VC and the tweeter VC, unlike other concentric designs that used completely separate units, such as the Altec 604s (model # correct?) is 4" long.

'Course, Tannoys are most certainly not the ultimate speaker, hence my desire to tweak them and why I am continuously swapping speakers to suit the music and my mood. I can say that the point source design has done a lot to improve my musical enjoyment in my moderately small room where I can't get far enough away from non-PS speakers to allow for decent driver integration.

I'm a lousy speaker fan, I'm infidel to brands and find faults in speaks others consider lifers.

Guess I'd better end this hijack before Kelly threatens to put his MTX car subwoofers in my Tannoys. :zoom:
- JP

 

[Mike Stehr]

I picked up a 12" Realistic/Utah "Americana" from a friend, and found another on eBay for cheap.

They are a 12" woofer, with a whizzer cone, and a cone tweeter.
The tweeter was crossed over with a 2 uF cap. The cone tweeters didn't impress me the least, so I unhooked them and use a Selenium ST324 slot tweeter on top capped off at 2 uF.

I have them in 3, 3 and a half foot volume cabinets sealed, with about 2, 3 pounds of polyfil. They roll-off at 40 Hz, but they sound like they dig down lower than that.

With a 2A3 amp, these speakers shine. The bass is quite impressive, and the midrange is really, really impressive. I can play Meat Beat Manifesto through the 2A3 amp and the Americana's just cruise right on down low as a subwoofer. (Or it sure seems that way....)

They can boogie on my JVC AS-5 solid state integrated amp as well.

For a cheap-assed driver, they sure sound good to me.
Sleepers........

 

[wualta]

I get the idea behind time aligned but will this not only work if you are exactly the right distance from the speaker to make it all happen?

Sorry, kfa, I've been neglecting your questions. Let me go back a bit. Yes, you are correct that in 99.8% of the speakers you will randomly encounter in your lifetime, which will have spatially (usually vertically) separated woofers and tweeters, time-alignment will only truly work along a paperthin horizontal arc in front of each speaker. Squat down at exactly the right height and hear, however momentarily, waveform fidelity. Of course, all the unaligned sound from all the rest of the speaker's output is bouncing all over your room, drowning out the miracle.

You guys can fool around with your goofy multi speakers all you want, I'm sticking to the single speaker systems.

Wait, come back! We're on your side! Charivari is talking about the special case of his Tannoys, which try to pretend they're a single driver by making the tweeter live under the woofer's dust cap and share the AlNiCo.

Me, I'm just nattering on generally about the unavoidable evils of crossovers and spatially separated drivers and how you, yes YOU, could be the vanguard of a mainstream revival of single-driver speaker systems and coax drivers like the Utah described by Mike Stehr and the KEF Uni-Q and instructive little micro stereos like the JVC FS-5000 with its dynamically-EQ'd little 3" fullranges.

First it was sand filled baffles...

Cripes, that's old. Doesn't that go back to the '50s with G.A. Briggs and Wharfedale? Where do you kids pick up on this stuff? It's freakin' amazing.

...then Mylar, now single speaker.

Mylar must mean Maggies. They coulda been a fullrange contenda. But it was necessary to get some treble dispersion, so the later models use a vertical line-source ribbonish tweeter. And don't they still have separate woofer and midrange panels?

The speaker with the Best Potential to be a Practical Fullrange XOL Speaker Using Mylar in a Dramatic Series? Acoustat's Spectra models, with their electrically segmented single electrostatic panel, as differentiated from QUAD's ESL-63 with its physically segmented panel(s).

The recommendation to get some Ohm Walshes and a set of electrostatic headphones was aimed generally, but at you in particular.

I'm fickle... or I just like the merits of all these designs.

I think you just like speakers. You know, of course, deep down, that they shouldn't work, they couldn't possibly work, it would be a screaming miracle if they.. but they do. Plausible illusions spill out of them all over your nice clean floor. That's hard not to like.

.

 

[wualta]

That's why you need to buy my future audiophile product, a special air spray that improves sound propagation in your listening room at only $572 per 12 oz can.

This is bloody brilliant! You have separated drivers and a passive crossover but you want waveform fidelity. What to do? Why, change the air! Make it less or more dense as needed around the room to adjust propagation velocities so as to make the wavefronts from all the drivers cohere no matter where you are in 4-pi space! Love it!

I'm uncertain about this, but I do believe Magnepans are phase aligned, but not time aligned. Am I right, Wualta?

You're askin' me? Without actually measuring them, my guess would be that if there are separate conductors on the Mylar and they go to separate legs of the crossover, the W and T panels could be in any phase/time relationship they want to be, and just because they share a single floppy sheet of Mylar [side by side?] doesn't mean they couldn't operate more or less independently. And on the expensive Maggies, the tweeter is an entirely separate unit mounted coplanar with the woof/mid. So the answer is, it very much depends on what the crossover Magnepan uses is saying. The panels will simply speak what the crossover tells them to.

And what, exactly, occurs in an actual Magneplanar, I don't know. Try sending a 1KHz square wave through one at a low level and set up a mic and a 'scope. Over the years, someone must have done this test. Very, very few speakers can pass it and output a recognizable square wave. Here's a good discussion of a difficult subject over at AA (Audio Asylum, not the other AA. That comes later.).

Even if we nail down this phase/time alignment concept or even the wave/particle nature of cats, I don't mean to imply that the wonderful measurable wavefront coherence produced by a single well-behaved diaphragm driven full range is the only explanation for what we hear. We hear, or believe we hear, something more closely approaching real life. Coherence is just one stab at an explanation for something that is ultimately noumenal and interpretive rather than phenomenal and objective. There may be many other things contributing to the illusion that we are hearing something closer to "live" sound than the something our conventional speakers deliver, and that's definitely outside the scope of this paper. However, if we put our money on the simpler XOL design, whatever form it takes, I don't think we'll be said to be deceiving ourselves.

 

[kfa888]

Great discussion guys, and interesting stuff. Well worth the $12.99 investment to spur this kind of discussion. It strikes me that really time aligned is not really possible. I would think to truly do that you would need a flat cone (FR sony APM :>) and nothing for the signal to bounce off of from the second it leaves that cone until it hits your ears. No possible. I assume they are just attempting better alignment with this approach. With a cone speaker the signal paths cross each other, filtering and cancellation happen and it shoots out at all directions.

As for the "sand" statement, Yes I meant Wharefdale which I have a soft spot for and currently own a nice set of W90's that I love and 2 sets of W60's which I also like a lot.

Mylar was in fact in reference to my Maggies which are the top of the heap at my house sonically even tho they are finicky, hard to drive and placement is problematic. Oh, and yes, Maggies should be considered two ways, different tension on the Mylar, different gauge wire, and XO's but all on one panel of Mylar on my MGIIA's

And yes, I love speakers. There, I said it.

JP and I seem to share a lot of things in that he has Maggies, Tannoys and Design Acoustics which are all extremely different speakers.

To come full circle back to the single driver thing, after a long day of semi critical listening and then setting the Wharfedale W90's back up where the maggies were and earlier the FR Utah's the W90's still impress big time BUT do not have that something the FR Utah's do. Something to take from every design and that is the fun part.

 

[Charivari]

This is bloody brilliant! You have separated drivers and a passive crossover but you want waveform fidelity. What to do? Why, change the air! Make it less or more dense as needed around the room to adjust propagation velocities so as to make the wavefronts from all the drivers cohere no matter where you are in 4-pi space! Love it!

Hey, if people actually buy C37 lacquer, then they’ll buy anything. So, why not take advantage of these placebo effects and use it to pay for system upgrades?

Quote:
Originally Posted by charivari
I'm uncertain about this, but I do believe Magnepans are phase aligned, but not time aligned. Am I right, Wualta?

You're askin' me? Without actually measuring them, my guess would be that if there are separate conductors on the Mylar and they go to separate legs of the crossover, the W and T panels could be in any phase/time relationship they want to be, and just because they share a single floppy sheet of Mylar [side by side?] doesn't mean they couldn't operate more or less independently. And on the expensive Maggies, the tweeter is an entirely separate unit mounted coplanar with the woof/mid. So the answer is, it very much depends on what the crossover Magnepan uses is saying. The panels will simply speak what the crossover tells them to.

Well … yeah. You obviously know about this stuff and I’m just plodding through, so I deferred to the expert. I thought one of the selling points of planar speakers was phase coherence, but I was uncertain. The newer, more expensive Maggies actually use two, sometimes three separate panels with a ribbon tweeter on the side, so it’s definitely up in the air.

And what, exactly, occurs in an actual Magneplanar, I don't know. Try sending a 1KHz square wave through one at a low level and set up a mic and a 'scope. Over the years, someone must have done this test. Very, very few speakers can pass it and output a recognizable square wave. Here's a good discussion of a difficult subject over at AA (Audio Asylum, not the other AA. That comes later.).

I suppose I could do that, as I dragged home a spare o-scope this past weekend from storage. Figured it was time I had one on hand, but I was just a child the last time I used one, so it’ll take me a while to relearn it. In time, I should be able to measure the square wave output as best I can in my room and with my equipment. Yet, I must ask, what’s the point? I don’t listen to square waves, cannot for that matter, and I doubt my hearing is sufficiently super-human to detect a minute difference in rise time. Come to think of it, a true square wave is impossible to reproduce, no matter the mass of the diaphragm, so this would only be extrapolation.

Now, Kelly, since you seem to be fond of the Magnepan sound and of single drivers, have you looked into the newer model MMG-Ws? They’re a single driver Maggie, designed to be wall-mounted, so they don’t have much down low. However, they do have no crossover or the like. Putting a pair of those atop a pair of dipole subwoofers could very well give you the best of both worlds.

- JP

 

[wualta]

I suppose I could do that, as I dragged home a spare o-scope this past weekend...

That's why we picked you for this specially dangerous mission, boy.

Yet, I must ask, what’s the point? I don’t listen to square waves, cannot for that matter, and I doubt my hearing is sufficiently super-human to detect a minute difference in rise time. Come to think of it, a true square wave is impossible to reproduce, no matter the mass of the diaphragm, so this would only be extrapolation.

Oh, now, don't turn all square-wavophobic on us at the crucial juncture. Of course you can hear a square wave. It may not be allowed on some religious fora, but you have our permission to do it here. And of course you can reproduce one. It's not easy, but some speakers have been known to do it, and I'll bet a Stax electrostatic wouldn't mess one up too bad. I'd expect to see ringing and a tilt and a ragged, rounded leading edge, but it would be recognizably squaroid.

All we're after is a quick and dirty method to see if the lows and highs of a Maggie are more or less lined up and speaking together. If they are, fantastic, and if they're not, it might still sound fantastic, but we'll know that the usual delays and phase shifts are happening and no big deal, it's speaker business as usual, no need to boo hoo or pooh pooh.

Square waves just happen to be a handy tool for showing this "alignment", if it's there. Remember, a square wave is made up of nothing but a specific series of sine waves summed together, and you do listen to sine waves summed together all the time, don't you? Remember Fourier and say yes. Can you directly correlate sound quality with the results of a 1KHz squarewave test? It would be risky at best. Could you see things like stored energy and phase inversion and delay and overshoot happening? Sure.

 

[Charivari]

Nope, I can't hear a square wave, but I can hear the result of one being mushed a bit by the electronics and speakers. A true square wave should have infinite slope, ie zero rise time. It's a theoretical thing that cannot be reproduced. However, something that looks kind of like a square wave on an o-scope with a minute rise time, perhaps imperceptibly so, can be done, but on the scales were talking about, nope. A true square wave would require something funky in the quantum realm. To that end, I know my ears are biomechanical and have a very sluggish response to transients, so they smear a squarish wave anyways. Besides, I won't only be measuring what the Maggies can reproduce, but what the microphone is able to translate from mechanical to electrical -- never could afford a good ribbon element.

At any rate, I'll have to throw together a couple of adapters, no biggie, to do it, but first I need to find a software audio sig gen that can produce a pseudo-square wave signal for testing as my trusty old HP 200CD can only do sine waves.

- JP

 

[Charivari]

Back on the subject of single driver, crossoverless speakers, how about this new Jordan JXR6? Full-range 2" driver, should be able to approximate a good point-source speaker without issues found with other full-range cone drivers (limited frequency range, beaming, all the detractions of whizzers, etc).

- JP

 

[packrat]

......
The speaker with the best potential to be a practical fullrange XOL speaker using Mylar in a dramatic series? Acoustat's Spectra models, with its electrically segmented single electrostatic panel, as differentiated from QUAD's ESL-63 with its physically segmented panel(s).
........

Just came across all this discussion....

The 57 had a central tweeter and a pair of bass panels, so the off axis horizontal response might have phase problems.
The 63 has one large diaphragm with an electrical delay line in the stators (which I do not really understand) to make the signal appear as if it originates from a point behind the speaker (according to Quad literature from the time). The phase response is very flat, making it a time aligned single driver speaker. Of course it has a low impedance and low sensitivity and is therefore not easy to drive.

My vote goes for Tannoy as the best compromise for wide range, good phase response, nice impedance, decent sensitivity, and simplicity (2-way). Not the best of one thing, but very good all around. The modern designs place the woofer and tweeter voice coils even closer so they achieve a nearly flat phase response.

I just wish they would make the modern 10 incher with a paper cone and a lower fs. If it had t/s parameters close to that of the old Advent 10" woofer, it would be my (maybe not your) nearly ideal speaker.

 

[wualta]

The ESL 63's diaphragm is special. Its segments are intentionally delayed so that the speaker creates a segmented but approximately spherical wavefront, shaped something like a lighthouse's Fresnel lens. So technically it's not time-aligned, because it's intentionally, well, re-aligned. But in this case, this is not a bad thing. Unless you believe that a point source shouldn't be the ideal for this type of speaker.

Come to think of it, this is rather important, and seldom considered. What sort of ideal speaker is a given designer/company aiming toward? Bose, for example, considered the ideal speaker to be the massless pulsating sphere, which goes a long way toward explaining the early 2201 and the later simplified 901. But if you don't like or agree with the designer's ideal, you probably won't like his speakers.

Chari: the Jordan efforts over the years show a brave concentrated effort to produce a do-it-all driver, which I applaud. The problem, as always, is cost. I've been trying to get people to find, buy and carefully listen to JVC's line of single-driver "executive" or "micro" stereos as an affordable way to learn the virtues of XOL. Obviously JVC was inspired by Jordan.

 

[Johncan]

I just got back from the Goodwill... I was dropping off clothes. They have a pair of large Utah speakers in cabinets that look very similar to the ones kfa888's just purchased. They are $32 for the pair. The cabinets are a little rough. The model number started with either CS or SC (I don't remember which).

John

 

[kfa888]

Update...

Well I was setting up my home office a little more today and thought I would set the single driver Utahs up in there and try them with my newly acquired SX-707 20 watter. All of a sudden they have a bunch of bass. WTF? maybe it was just amp matching, maybe it is that the room is much smaller, maybe it is because they are near the back wall, maybe the placement made that much difference? Not sure but now i have a totally different opinion of these speakers. i really like them. I do need to EQ the HF to the plus side to make them sparkle a little.

Good stuff. :thmbsp:

 

[macaltec]

Update...

Well I was setting up my home office a little more today and thought I would set the single driver Utahs up in there and try them with my newly acquired SX-707 20 watter. All of a sudden they have a bunch of bass. WTF? maybe it was just amp matching, maybe it is that the room is much smaller, maybe it is because they are near the back wall, maybe the placement made that much difference? Not sure but now i have a totally different opinion of these speakers. i really like them. I do need to EQ the HF to the plus side to make them sparkle a little.

Good stuff. :thmbsp:

You and JP with your oddball speakers sicken me uke2: I want some :tears:. These conventional speakers are all starting to sound the same to me (except the Infinities).

mac

 

[kfa888]

I have been listening to these for about an hour or so now and am amazed by the sound, so clear and detailed. I'm very surprised. Vocals and smooth guitar work sounds great and seems to have more something to it. Really hard to describe. Very surprising from a single cone / no XO, no trickery needed. Like i said I needed to jack the HF a little but after doing that it is as full range as a lot of 3 ways I have heard and more cohesive than most. Fascinating. I have to get a tube amp. Eric Johnson and Dire Straights are sounding real good. Bela Fleck was also sounding great earlier.

 

[macaltec]

I have been listening to these for about an hour or so now and am amazed by the sound, so clear and detailed. I'm very surprised. Vocals and smooth guitar work sounds great and seems to have more something to it. Really hard to describe. Very surprising from a single cone / no XO, no trickery needed. Like i said I needed to jack the HF a little but after doing that it is a full range as a lot of 3 ways I have heard and more cohesive than most. Fascinating. I have to get a tube amp. Eric Johnson and Dire Straights are sounding real good. Bela Fleck was also sounding great earlier.

Keep rubbing it in. Bet it would sound better with an M&K subwoofer :yes: .

mac

 

[Charivari]

You and JP with your oddball speakers sicken me uke2: I want some :tears:. These conventional speakers are all starting to sound the same to me (except the Infinities).

mac

I think we have a convert. :thmbsp: Welcome to the dark side of vintage speaker loving, those Infinities were just the beginning. :yes:

- JP

 

[wualta]

Yeah. Remember, conventional speakers just sound like.... ...speakers.