I want to add some important information to this posting. The "new" reproducer design that I talked about here was originally designed by Tom Kimble who is another phonograph and record collector. He has considerable design experience as he was a mechanical engineer at Baldwin Piano and Organ Company, and he holds a number of patents in piano mechanism design. He designed and made one of these reproducers eight or ten years ago. I saw this design and wanted to play around with it, so Tom gave me his original drawings. I have now received his approval to credit him with the original design. I haven't said much about it otherwise because I don't really have a product design that I feel is ready to market. I only mentioned it here originally to indicate that it is, indeed, possible to design an acoustic reproducer that outperforms all known early designs, including the Victor orthophonic. I have started with Tom's original design and made several changes to it, but I still don't have a product that I'm fully satisfied with. So this is not a product that I'm trying to hawk or to market. I just want to set the record straight that the design originated with Tom Kimble. Greg Bogantz ----- Original Message ----- From: "Greg Bogantz" <gbogantz1 at charter.net> To: "Antique Phonograph List" <phono-l at oldcrank.org> Sent: Friday, February 08, 2008 11:10 PM Subject: Re: [Phono-L] Victor versus Columbia big guns > Hi Robert, > > To answer your general curiosity, yes, I > have tried many of the things you suggest. I have designed and made a > complete "New Orthophonic" (with apologies to RCA who couldn't care less > at this point since they're owned by the Chinese) reproducer to fit Victor > ortho tonearms out of lathe-turned aluminum - none of the parts are > recycled > from old designs. The aluminum model weighs about half of the potmetal > design. I don't want to divulge too much more of the design in case I > eventually want to make and market it. But it really isn't ready for that > yet. Even so, I don't know how much market there would be for a toy like > this. Most phono collectors don't obsess about the audio performance of > their acoustic machines like you and I do. Their attitude is that > anything > that isn't an original 100 year old design constitutes a "frankenphone" > and > they don't want anything to do with it. So I'm not encouraged that there > are more than a dozen of us with this interest. > > As an adjunct to this design, I also have been making for some time now > my own tungsten needles. This started out because I needed durable > needles > to use in my oldest record changers that are designed for steel needles. > Steel needles are no good for these changers because they wear out > completely after two record sides are played. So, what's the point of > having a record changer if you have to change the needle every two record > sides? Victor recommended their Tungstones for this purpose, and indeed, > they were the best choice for this application at the time. But I didn't > want to use up expensive, original, antique Tungstones so I designed my > own. > What I found out was that the original tungsten wire used by Victor is > .007 > inch (7 mils) in diameter. This is really too big for the typical groove > which is around 5 to 5.5 mils in width. But they used it because anything > smaller is too delicate and bends too easily. Also, the heavy tracking > force of the early reproducers, both the acoustic and the early horseshoe > magnet electric types was sufficient to mash the fat wire into the record > groove and keep it working even though it was wearing "shoulders" on the > sides of the too-big wire. So when I tried to use these 7 mil tungstens > in > my new reproducer which tracked at half the force of the Victor (about 80 > grams versus 135 grams), the wire didn't wear down properly on the > shoulders > and stay in contact with the groove walls. This caused audible > mistracking. > I have since gone to 6 mil wire which works pretty well. I would rather > use > 5 mil wire, but I've tried it and it's just too fragile and bends too > easily. So this is yet another problem that requires some compromise. > > To address your suggestions about using large diaphragms: you are > faced > with a tradeoff between diaphragm compliance, resonance, and application > requirements. If you want to try a "Lumiere" type of very large > diaphragm, > or direct radiator cone really, then you can't effectively horn load it, > and > you probably don't want to anyway. You can simply let such a large > vibrating surface radiate directly into the surrounding acoustic space as > is > done with the Lumiere and Pathe Actuelle designs. Such a design can sound > pretty good in the midrange of audio, but it is inherently limited in how > much bass it can reproduce - there just isn't efficient coupling with the > air mass at very long wavelengths of audio (bass frequencies) to get good > bass response. To load a large diaphragm into a horn would require a > large > horn throat to accommodate it. Which would require a VERY large horn to > work into to keep the compression horn acoustic principle working > properly. > Improper mismatches in sizes here result in vastly reduced efficiency. > > Long story short(er), the approximate sizes of the diaphragm, > reproducer > throat, and horn length and flare are just about optimum as realized in > the > Victor designs for the application of playing 78rpm records with 5 mil > wide > grooves. Bigger systems would require bigger records and bigger grooves > to > keep the mechanical couplings and impedance transformations working > correctly. Loading a typical 78rpm groove with a correctly-designed large > diaphragm compression horn system would simply cause too much mechanical > loading on the needle. This would result in very low compliance at the > needle tip which would result in severe mistracking. Furthermore, the > extreme mass of the entire system would be difficult to track with a > pivoted > tonearm under groove power, as you suggest. But lateral-cut records do > not > lend themselves to feedscrew-type tonearm assist systems because most > records are not cut at a constant groove pitch which cylinders are. Then > there's the problem of record eccentricity that must also be accommodated. > You could address these issues with a sophisticated servo-controlled > tracking system. But it all adds up to swatting a fly with a sledge > hammer. > So it turns out that the approximate sizing of the playback elements as > seen > in the Victor (and others) designs is probably about optimal for real > world > use. But that doesn't mean that you can't put a considerably larger horn > on > a Victor-sized system. To do so would extend the bass reproduction > frequencies down lower. Victor themselves did that in their theater-sized > horn designs. But the efficiency tends to degrade with increasing horn > size, so even the biggest theatrical Victors used electrical horn drivers > and electronic amplifiers. > > You mention the excesses of the Archeophone design: True, this is > pretty much overkill, too. But there really aren't any modern cylinder > player designs that offer highly accurate record speed and vanishingly low > flutter, so these are two design criteria that are purposefully addressed > in > the Archeophone. However, the basic business of turning a disc record and > holding a reproducing means in the groove have been developed for years > past > the acoustic technology as embodied in all modern disc record players. > All > that really needs to be done if you want to extract the most from a disc > record is to use a modern hifi pickup equipped with the proper size and > shape stylus. Done deal. It doesn't need re-inventing. > > But I DO understand that you are trying to "squeeze the turnip" and see > how much blood can be extracted from pure acoustic playback technology. > But > I CAN tell you that it is NOT possible to make the "perfect" acoustic > reproducer - you can't get fully wideband frequency response AND > low tracking force AND good efficiency (loudness) from an acoustic design. > It's just not in the physics. Unlike the situation with modern hifi > pickups, the physical requirements of an acoustic reproducer are vastly > different. The modern record player does not require anything more of the > record than to merely "instruct" the player on how to direct its > electrical > energy to the loudspeaker. This requires an infinitesimal amount of power > from the groove. By contrast, an acoustic player extracts ALL its sound > power from the record groove (assuming you aren't using a mechanical > amplifier such as the Higham friction amplifier or compressed air schemes > such as on the Auxetophone). This makes all the difference in the world. > Acoustic playback requires that all the audio power must be extracted by > making the record groove do the actual work. The more work the groove > must > do, the more wear is likely to be exhibited as the needle scrubs along the > groove walls. You quickly get to the point where you can't get any more > blood out of it. The Victor design is close to the optimum, in my > estimation. I've been able to improve upon it, but I don't expect that > too > much more can be had from what I'm getting now. But I'd love to be proved > wrong, if someone wants to have a go at it. > > Greg Bogantz > > > > ----- Original Message ----- > From: "Robert Wright" <esroberto at hotmail.com> > To: "Antique Phonograph List" <phono-l at oldcrank.org> > Sent: Tuesday, February 05, 2008 10:16 PM > Subject: Re: [Phono-L] Victor versus Columbia big guns > > >> Wow, thanks for all the great information, Greg, and thanks for taking >> the time to type/copy&paste it all! I'm wondering additionally about >> using space-age materials and creating something using a Victor horn >> that's beyond comparison with any antique products of any kind. I'd like >> to see, for starters, what a larger diaphragm suspended by a rubber >> surround in a milled aluminum soundbox with a titanium stylus bar and >> razor blade pivot point would do mounted to a Credenza tonearm. With a >> larger diaphragm and soundbox, some counterbalancing (a la Ultona) might >> be necessary, but with aluminum instead of brass, maybe not. >> >> That's just for starters. I'd also be interested in creating an even >> larger soundbox, say 10" or so, with similar materials (think modern HMV >> Lumiere), mounted rigidly (laterally speaking) to a large, non-folded >> exponential horn (a la Nimbus Records'), with a modern direct drive >> turntable mounted to a feedscrew stand so that the disc moves laterally >> under the stylus (think Wizard or other moving-mandrel cylinder phonos). >> Maybe a titanium diaphragm to keep moving mass to a minimum... Granted, >> this would be truckloads of cash to build, but I figure if they can build >> the Archeophone... >> >> continuing to dream, >> Robert >> >> >> >> ----- Original Message ----- >> From: "Greg Bogantz" <gbogantz1 at charter.net> >> To: "Antique Phonograph List" <phono-l at oldcrank.org> >> Sent: Tuesday, February 05, 2008 8:34 PM >> Subject: Re: [Phono-L] Victor versus Columbia big guns >> >> >>> Well, Robert, I think I agree with you that the Credenza is the >>> standard of excellence in American acoustic reproduction. I have an >>> early 2-door Credenza as well as a Victor 10-50, 9-40, and 10-35 as well >>> as a Columbia 810 which has the biggest horn that Columbia put in their >>> Viva-Tonals. I don't hear too much difference among the big Victors, >>> but each has subtle differences from one to another. All are GREAT >>> machines, and any owner should be proud and pleased to listen to them. >>> The reason that I put that caveat about American acoustic reproduction >>> is that I haven't had the pleasure of hearing any of the really good >>> English machines such as the biggest re-entrant HMVs or the biggest >>> EMGs. Maybe one of them can claim the prize as best acoustic machine, >>> but I just can't say. I must opine, however, that I can't imagine the >>> EMGs having as good bass as the biggest exponential horn machines simply >>> because EMG didn't use as big a horn! >>> >>> Now, with all due respect to Anthony Sinclair, and I truly do mean >>> that I respect and applaud his efforts to document the performance of >>> orthophonic and other machines in his writings in ITG, I must beg to >>> disagree with some of his opinions. By the way, we've recently had some >>> of these very same discussions on the Old Time Victrola Music Message >>> Board (OTVMMB), but I'll repeat here what I've written there for those >>> of you who aren't also members there. I encourage you folks to go there >>> and see what else has been said recently about this topic. I don't >>> presently have the proper instrumentation to back up my claims, but I've >>> listened extensively to the big horn Victors and compared them to the >>> Columbia. I have made an adapter that allows me to listen to the >>> Columbia #15 Viva-Tonal reproducer played thru the Victors, and also >>> allows me to use the Victor orthophonic reproducer on the Columbia. I >>> was particularly interested in whether the horns or the reproducers were >>> the limiting factor in acoustic reproduction on these machines. >>> >>> In my opinion, the Columbia horn is not as good as the Victor. The >>> Columbia horn is not as accurately tapered because it is constructed in >>> a piecewise-linear-curved sectional fashion rather than having a >>> smoother, more uniform and proper exponentially increasing cross section >>> which is required of the exponential design. There should be NO >>> cross-sections in a proper exponential horn which are linear taper. >>> This, in particular, causes the treble to be noticeably weaker than the >>> Victor. But the bass is also less extended as well. And, overall, the >>> efficiency isn't as good as the Victor (it doesn't play as loudly) - all >>> these attributes are symptomatic of an incorrect horn taper. At first >>> blush, the Columbia strikes the casual listener as having more bass, but >>> this is due to it's having substantially less treble than the Victor. >>> >>> Another finding indicates that the big Victor horns are better than >>> people realize because the Victor reproducer isn't as good as the big >>> horns. More on this later. The Victor ortho reproducer has several >>> compromises included in its design to make it more robust and more >>> user-friendly that, unfortunately, detract from the best acoustical >>> performance that could have been had. The bass could be a little better >>> if the compliance was higher, and the treble could be a little better if >>> the moving mass was lower. That said, the Columbia #15 is no match for >>> the Victor ortho. It has a more massive diaphragm which further >>> degrades the treble, and the compliance is even lower (stiffer) which >>> further degrades the bass, compared with the Victor. The Columbia has >>> the very big advantage that it is all made of brass and is easily >>> rebuilt, but it still can't match the performance of a Victor ortho in >>> good condition. >>> >>> The reason that I know the Victor horn is capable of more than most >>> people realize is that I have designed a better reproducer than the >>> Victor. My design has a MUCH lower moving mass and quite a lot higher >>> compliance than any other reproducer that was sold to the public. >>> Incidentally, I was particularly interested to see if this could have >>> been done "back in the day" by trying to use only materials that would >>> have been readily available in 1927 or so - no modern space-age >>> materials. And I discovered that it could have been done - the >>> materials are aluminum, leather, and paper with a few screws and glue >>> thrown in to hold it together. I guess the reason why a design like >>> this wasn't marketed is related to the delicacy of a proper design. The >>> low moving mass and high compliance both make the reproducer delicate >>> and difficult to perform needle changes. I'm sure my design would never >>> have been suitable for mass consumption, but I like to use it because it >>> makes the Victor horn really shine! Reproduction on this system sounds >>> like that of a large table radio or small radio console - I estimate >>> that it has about an extra octave of useful output, some above and some >>> below the range of the Victor ortho. The bass is not window-rattling, >>> but it's uncommonly good and the sound is well-balanced and wide-range >>> without peakiness, and most listeners can't believe that they're hearing >>> acoustic reproduction. So, yes, the big Victor horns are the best >>> acoustic horns that I know of and are damn fine at that. >>> >>> Greg Bogantz >> >> _______________________________________________ >> Phono-L mailing list >> http://phono-l.oldcrank.org > > _______________________________________________ > Phono-L mailing list > http://phono-l.oldcrank.org