Full Range Driver and Single Driver Speakers

[Ducatista47]

I thought discussions of other speakers were off topic to the forum and not associated equipment, but since a Super Moderator suggested this thread be created here it is. Thank you, Widget! Because this topic is more general than any specific speaker or brand, I have placed it in General Audio Discussion.

I am talking about Hammer Dynamics Super 12 speakers in particular here, but by way of comparison this could be all over the map. This realm is called Full Range Drivers and is almost identical and coincident with Single Driver speakers. Open Baffle is an installation subset of this field. Let me speak generally about Full Range and with the background in place the Super 12’s might make some sense.

One of the problems with multi way speaker systems, that would be two way, three way, four way, etc, is the crossover point(s) always dividing the really important frequencies where the fundamental tones of musical instruments and voice reside. Not the deep bass or the highs, but where the heart and soul of the music lives. Thus the famous phrase, “We live in the midrange.” As will be noted by the development of bypassed and charge coupled crossovers, dividing frequencies with networks (crossovers) gives rise to certain problems that affect music reproduction. We are always trying to minimize these side effects, but when great sources, great amplifiers and decent listening rooms and hearing are brought together, we can hear these effects and given a comparison to listening experiences where this is not the case they sound bad. They get between us and our music, and after all this pursuit of ours is all about the music.

What are these better listening experiences where this is not the case? Live music and full range driver reproduction where any crossover points fall outside the range of frequencies where our sensibilities are offended if the reproduction is compromised in some jarring way. The reason for multi way speakers is to use a mix of transducers that by their specialized nature allow better reproduction of each selected frequency band. Good idea, but not quite so good if we make two or more frequency bands out of the range where our music appreciation “lives”. This problem manifests itself not only with crossover distortions but also with different individual transducers, often even different types of transducers, non identical at least, producing adjoining frequencies. In reality, they are not only adjoining but also overlapping – even with very steep crossover slopes. When you have a bigger cone and a smaller cone, a cone and a compression driver, a conventional driver and a helium tweeter, whatever, these different versions of the same frequencies and of adjoining frequencies create problems. All this should sound inaccurate and strange, and it does. Yet another set of differences between live music and our reproduction of it.

So why are stores not full of Single Driver systems? Well, they once were. Then music reproduction went from 60-9000 hz to 20-20000 hz to 16-45000 hz. Designing a full range driver with good sound for 60-9000 was hard enough. Any more range and the compromises ruin the sound. Now there are still attempts at Single Driver systems, but Full Range plus some help on the low or high end are what is happening more and more.

Widget mentioned the Lowther and Fostex based systems. These cone speakers are still being installed in an endless parade of enclosures designed to overcome their sonic problems. Especially in the case of Lowther, a very old design that is very expensive to produce properly, the bass response of these small, stiff cones falls off the table as high as 300hz. Rather than dropping like a stone, it was noticed that the response falls in a curve. Steep, but a curve that does go below 80hz. What is required here is a very complex horn that has a rising rate bass response exactly opposite the falling response of the driver. If you think designing enclosures for multi way systems is challenging, try this hair pulling exercise. They are still trying to get it perfect, but of course nothing is. People familiar with great sound but not with these systems often hear another issue immediately. The direct sound from the cone sounds different from the horn output in many respects. Essentially two different sounding transducers; a single driver two way system.


So what are we to do? Give up? No, there are other workable solutions. Design a driver full range from 100hz on up and use a sub. Omega makes a range of small speakers like this, and home built Fostex and Lowther systems go this way sometimes. JBL used to make a speaker that was superb at this, but it is I understand long gone. The library has specs for the LE8T. http://www.lansingheritage.org/html/jbl/specs/home-comp/le8t.htm


Another solution is to make a larger driver and use a super tweeter instead of a sub. There is one example I am personally aware of, and this brings us to the Hammer Dynamics Super 12.

[Ducatista47]

A Full Range driver that is good at reproducing sounds up to 13k or 18K hz is going to be small. And they are. Lowther, Fostex and the others are usually six or eight inch speakers, even with whizzer cones to help out with the highest frequencies. Some are four inch, to eliminate the need and attendant problems of whizzer cones.

These small cones have a big problem. Dynamics are quite limited. Full time listeners of Single Driver speakers tend to do the audiophile thing, listen at lower SPL’s and live with the small dynamic range. For folks like us here, including myself, this is not acceptable. Live music has balls and so should recorded music.

For a Full Range driver with a sub, the sub may have good dynamics but the rest of the system does not. This is where Super 12’s come in. A violin player by the name of John Wyckoff was looking for really great sound reproduction, I think for personal listening. He noticed that very small triode amps gave startlingly real rendition. Argue if you wish, but I personally have found this to be the case as well at this point. At least the one I have does. Mr. Wyckoff also discovered that there were no affordable speaker systems designed for these under six watt – often 0.9 watt – amps. Frankly, my friends who get to attend the shows where very expensive speakers are shown tell me the high dollar offerings stink at this anyway.

John saw a different approach. Full range problems could be overcome. Making a larger cone was the breakthrough. That would bring back the dynamics and improve the quality of the added transducer. Why not use a fast super tweeter instead of a slow subwoofer?

One reason a large Full Range driver had not been tried (coax drivers are not Full Range drivers but two very different drivers on axis) was the difficulty of getting a larger whizzer cone to go high enough. Use a super tweeter from 9700hz or so up and a larger primary cone to eliminate the need for a subwoofer, and there go the two big problems.

This did leave some other problems. At the upper frequency limits of a cone, breakup occurs. A cone with a whizzer to extend the range has breakup too, but John figured out a design where the breakup modes were coincident. The big cone broke up at its upper range and the whizzer broke up at its lower range, where the frequency range was the same band. He would deal with them both together. How did he do this? He used a crossover to divide the system at 9700hz and built a parallel notch filter in the LF section to deal with the breakup modes. There is also a muscular Zobel across the big speaker terminals to further tune the system.

The other big idea he came up with was to balance the system almost perfectly by tuning the simple box to deal with what problems remained with the frequency response. What he came up with is a very specific solution that is a one off. It will only work with the transducer he designed and one would have to both start from scratch and come up with different solutions to do this with a different Full Range driver. It is not scalable. The ported enclosure is a pipe 13 x13 x 46.5 inches tuned to 500hz. It uses extensive, mutiple material damping to deal with the backwave and tune the frequency response selectively.

John was operating from a small cabin in the mountains of New Mexico and had to keep things simple for himself and affordable for his clients. He used an Eminence frame & motor and designed his own cone. I assume Eminence manufactures the drivers complete. The motor is modified to John’s specs. The original speaker, quite a different animal, is available for a very few dollars at Parts Express. I think it is the Beta 12LTA, a Full Range PA speaker. The other cost saving measure was to provide the speaker as a transducer/crossover kit with the enclosures to be customer built. A construction book completes the package.

John spent five years on this design before releasing it for sale. You may have noticed me mixing my tenses. John past tense, speakers present tense. That is because John Wyckoff sadly passed away about 2001, still a young man. His widow is a very nice lady who carries on the operation from the cabin. The kit is $650 shipped when I last checked. It is here: http://www.hammerdynamics.com/ John was known for his great support, and while Colleen is not capable of his expertise she is very friendly and helpful. Support is hugely available at http://fullrangedriver.com/ The Forum is excellent. The site is run by a wonderful man named James Melhuish.

How did I find out about the Super 12? Ian has a pair. Thank you again, Ian. I'll post later about my experience listening to this system if anyone is interested.

Clark

[Robh3606]

So why are stores not full of Single Driver systems? Well, they once were.


Hello Clark

Not to rain on the parade but they still are. I believe more than many think. The most successful "full range" design I know of are the infamous Bose Cube systems. They are low end augmented full rangers. Many would call that blasphemy but it's true. You have Gallo and a few others in there going for a good sounding small package that can live in most wives living rooms.

I had heard a couple of them one was an 8" full range field coil driver. It was simply outstanding. One of the nicest sounding midranges I have ever heard. I don't like the Lowthers or the Fostex's I have heard.

Rob:)

[Ducatista47]

Rob, you are not raining on my parade by providing good information. I was going to leave this for others to post about as soon as I completed my second, which you beat me to!

I was waxing nostalgic about previous eras, not today's world. When I was a lad my father had a basement full of many sizes of mono speakers so he could walk around and hear his music. A few were coax but most were Single Driver. The stuff was to be had everywhere, cheap to audiophile. When you went somewhere to buy equipment, be it a store or a catalog, Full Range was one of the primary choices, not a sideline. I am talking about the 1950's here.

The 8" field coil sounds very interesting. Did it need a sub to round out the low end? I think a 12" would yield much better dynamics. Living with the Super 12 has me thinking that it might be the perfect Full Range size.

Clark

[Robh3606]

Hello Clark

Many people hear Bose and they cringe! My dad had several of those old full rangers around the house. I think one was a Utah and another an old RCA driver. There were all paper cones, no real bass but they were still enjoyable to listen too. He had the full-rangers in the garage and on the porch hooked up to an old all tube console radio chassis. He had his Altecs as well though in the living-room with his Warfdales.

I ended up with a pair of those as my "first stereo" speakers. I had a portable Sony "Superscope" RTR as my music source. I upgraded from the internal 5X7 internals to those as externals. I would record on my dad's RTR and use the tapes in my room. I have many a fond memory of those old drivers. You are right in the early 60's you could get them everywhere from Radio shack or Lafayette. The catalogs were full of them.

Those 8's were fine bass wise. They beamed a bit but in the sweet spot they really were a pleasant surprise. I have to figure out what they were and post a link.

Rob:)

[Ian Mackenzie]

Rob,

I sincerely doubt if the Bose end of the market would have an inkling of what hi end full range drivers are about. They are not your horrotones and ipod speakers. These are usually low sensitvity drivers not like the Coral Beta 8 and Fostex and others that are in the high 90's and this translates into large enclosures and horn loading.

One of the reasons they are not seen in mass markets is cost and limited production.

One of the few commercially successful full range systems is the Druid but then they use a horn super tweater and build i sub woofers.

[Robh3606]

I sincerely doubt if the Bose end of the market would have an inkling of what hi end full range drivers are about. They are not your horrotones and ipod speakers. These are usually low sensitvity drivers not like the Coral Beta 8 and Fostex and others that are in the high 90's and this translates into large enclosures and horn loading.

Agreed and I would not expect them too. There are exceptional designs in all driver types. You are looking at the cream of the crop in full rangers. Actually the high sensitivity types are at a disadvantage with such limited X-Max. I never got these designs that need augmentation on both sides of the bandwidth.

Rob:)

[Mr. Widget]

Living with the Super 12 has me thinking that it might be the perfect Full Range size.I was away for the weekend and missed this until now... I haven't personally played with full range drivers since my earliest speaker efforts back in high school. Back then I listened to music at insane SPLs and the 8" and 12" drivers distorted far too much... you could hear tons of harmonic and even FM distortion as the low notes broke up the HFs trying to come off those large cones.

At moderate to low SPLs a really good full range can sound very refined. At one point (early '80s?) I played around with Jordan Modules. These were nearly full range drivers that were 2" in diameter and were remarkably linear from ~150Hz up. They were quite good but you needed a line array to get any sort of SPL out of them and then they lost some of the magic.


Widget

[Ducatista47]

I should have added here that in my background discourse I may have misspoken or downright erred on some points. I'm human. And old! Perhaps if I was way off the mark on something Ian, Widget or any of the much more knowledgeable than I who visit here could set things right. I'm not embarrassed by being wrong and love to learn, so please feel free to correct or add to my take on all this.

My bottom line on Full Range is that Hammer Dynamics Super 12's and Omegas don't cost very much and can be extremely rewarding to listen to. With a nice Canton sub an old Omega obtained for peanuts yielded the best imaging and the most in-the-room presentation of sound quality I have ever heard. It is limited in the types of music it can handle. At reasonable SPL's Super 12's seem to handle anything. If really loud is your thing then Full Range is not. I encourage everyone else to give it a try.

If you build a pair of Super 12's you will be in a pretty exclusive club. I know the number of kits sold more or less and you will probably have the only ones in your little part of the World. It is time to stop keeping these a secret. I would recommend building the boxes with joinery like Macaroonie demonstrated (http://audioheritage.org/vbulletin/showthread.php?t=17238) and with a double thick front baffle as per Ian's suggestion, not as per instructions. I can advise on the required port changes and dimensions.

Clark

[Ian Mackenzie]

On the bass limitations many diy and commerical design efforts now use an additional helper woofer (see Hawthorn Audio Silver Iris OB but this is really a dual concentric driver), the (Pass Feastrex whizzer OB with OEM helper woofer) or mutiple drivers in an array (Visaton B200 whizzer ) with a special crossover to control the drivers running from a line source in the bass to a point source at high frequencies.

The idea of using a full range driver in an OB is an interesting spin on the design. As you can imagine it does not sound like a box/ bass reflex system. But you need a suitable room.

Anyone who thought full range driver system are not serious hi end loudspeaker needs to think again.

There are very expensive commerical system like the Druid that use 4 large powered woofers on the rear of the box and operates from 20 hertz . Its a case of retuning the box of the full range driver to control the Xmax and find a suitable helper woofer(2) and fire up your crossover software.

Not a particularly difficult project.

There are also some really expensive full range dual concentric drivers around now that start where the Tannoy and Altec left off

[Ducatista47]

Here is what I am talking about. A quote from a recent post on this very forum.


PS : I have to confess that full range drivers are not my cup of tea ! I listen a lot of jazz, not mandolin (with my apologize for full range lovers)The Super 12's are markedly different from this commonly heard perception. I listen almost exclusively to Jazz. Mostly very heavy Jazz, the kind that drives most listeners out of the room right now. The smaller coned Full Range drivers - that is, everything else - do lack the dynamics to play anything but acoustic combo or solo music and voice properly. Remember, the magic of Full Range drivers comes from a single, crossover-less transducer covering the critical range from say 45-9500hz. Adding helpers above or below does not change that. But the small cones usually used to render the critical range lack the necessary dynamics to portray other musical styles at what I consider satisfying levels with believable dynamics.

There is a reason why they are called Hammer Dynamics Super 12's. I read with amusement a post by a long time Lowther/Fostex listener complaining that his friend's Super 12's had way too much bass. There is simply no comparison.

What I listen to is very demanding of speaker and amplifier performance. The amp has to be very accurate, lively and natural. The speaker must have believable dynamics and very high efficiency. (I have never been even close to satisfied by the sound of any low efficiency speaker design or the amps needed to power them.) When I want Cecil Taylor, Ornette Coleman, Sun Ra, Jimmy Lyons or later (more violent) John Coltrane, Michael Brecker or Bill Evans in the room, the Super 12's deliver better than my 4345's. The 4345's whomp nearly any home made multi way design in dynamics and clarity. The Super 12's deliver enough of that and some of the best imaging available anywhere, a very satisfying - and very full-bodied - experience. It seems to be in an entirely different class from other Full Range and Single Driver systems and should not be confused with them.

Anyone can build a louder system, but it would be very, very difficult and expensive to equal what I am hearing from the standpoint of quality. In my 24 by 15 by 8 foot room, it is plenty loud enough, and that is with a three or four watt amp at nine o'clock. I listen to music. I'm not trying to impress a drunken frat party with an SPL contest. I turn it up until I think it sounds best, and that is louder than my family and many visitors are comfortable with.

Clark

[speakerdave]

This is where I came in, actually, tracking down information about full range drivers, and looking for some details about the LE8T brought up the Lansing heritage website. I read about this speaker then; it looks interesting, and it wouldn't cost huge sums to check it out. I'm glad Mrs. Wykoff is still in business. I think there is a place for this kind of speaker.

But I gotta say, when you say that it will reproduce a large jazz ensemble better than a 4345, I think we must be talking about different things. Basically, I think we're talking, on the one hand, about what can be done with a small tube amp, and on the other what can be done with music reproduction on another scale entirely.

I've got some Cecil Taylor, John Coltrane, JCOA, Ornette Coleman, Marion Brown, Charles Mingus. I can hear differences between the 4333 and the 4345, a 15 and an 18, an 18 and a pair of very excellent 14's per side, an absolutely stunning SOTA two way and the 4345, and I have to tell you, I think your focus shifts here and there. That's OK, but let's be clear about it. There are different styles of reproduction with different goals. There are days when I sit down and listen to some choral music with a tube preamp and amp and a pair of 10" coaxials, and I like it because I'm never distracted by the negative effects of four separate drivers. But at the same time, it does not take long to miss the body of the sound that is present when heard over the larger speakers, even of that kind of music. And when you add in a grand piano, a bass, and a drum kit, it's not even a discussion, really. And best of all, is that in the middle of that big speaker is that great 10" midbass giving you plenty of detail.

I too have an appreciation for an 8 x 10 print made from an exquisite Leica black and white negative, but I'll never (except just this once) speak if it and a wall-sized mural, that's all about engulfing presence, printed from an 8 x 10 negative in the same sentence; they are two entirely separate species of endeavor. I just don't see the point.

David

[Ducatista47]

That is a great comparison. When I did a lot of shooting my favorite work was contact printing my 8 x 10 negatives with a vacuum frame and developing the print with a Dektol/ Selectol Soft two tray system to render the tones better. Then selenium toning. I also used my Hasselblad a lot with PlusX to produce 8 x 8 prints, but I preferred the contact prints. That's where I'm coming from. Music is an intimate activity for me and I like its impact close up and personal.

I had no interest in large prints from the 8 x 10 negs. This was for my own amusement, not for billboards, so I could have the best of both worlds. Like with the stereo rig I use now.

I didn't say the Super 12's had as much dynamics as the 4345's, I said they had enough by plenty. And certainly way more than Lowther type designs, which was my point but I do tend to wander about when posting...;)

Clark

[speakerdave]

Yeah, there are days when I recognize that one really does not NEED a pair of 4345's in the living room. And I try not to forget that.

David

[Ducatista47]

You've got me there. I don't think either of us will ever be sorry to have the 4345 alternative ready at hand. Boy, are we happily spoiled.

Still, I was struck by Ian's recent posting about how twelve inch drivers are plenty for our listening rooms and cost less in money and real estate. In today's six inch woofer world that is such a revelation. I know I had seriously lost my perspective in the other direction.

Clark

[Ian Mackenzie]

Clark,

I am not sure in what context i said that

One think is for sure the smaller FRD's are best suited for particular genre's.

But dont expect any FRD to be a robust as a JBL driver

[Ducatista47]

I have stirred debate here, unintentional for sure, by drifting and rambling through topics that seem to give lie to one of the first things I said in this thread, and that was short sighted of me. Like sound levels, listening preferences and experiences are relative to one another.

When I said Full Range drivers, meaning used as the heart of a system or standing alone, were of no use for listeners who like it pretty darn loud, that was hard and fast. But what about those relative issues? Maybe I can clear the waters I have muddied myself.

Ian correctly states that a Full Range driver will never be as robust as a JBL. In the realm of taking a licking and keeping on ticking (an old Timex watch ad, for those too young or located elsewhere), that is true for sure. When listening at the levels I do, either will last a long, long time – probably longer than us. Has anyone out there fried a voice coil with less than loud, given clean power and no extra toys like DC or dead shorts?

I could break down listening levels into four or five categories for the sake of illustration. There is background music, never meant to be at the forefront of the sound present, at least not in the mind of the listener. I could say the non-listener, but that would be elitist. Then there are listeners enjoying music in their homes, with or without a party. Then there is playback monitoring for recording and mastering. At the loud end would be sound reinforcement, almost always in areas larger than rooms commonly found in private homes. That could go from lecture rooms to theaters and discos to outdoor venues. All these situations need speakers, but how different the demands placed on them are!

It is in the second category, home listening with the music as the main focus of the activity, that we usually find a niche for Full Range drivers. The question is do we want concert level or not and if so the level of what kind of concert? Some possible answers to these questions will put us into the sound reinforcement field of equipment and eliminate Full Range from the possibilities. For instance, if the goal is to have concert level SPL’s listening to AC/DC Super 12’s would not be the tool for the job. Then again, my hearing is pretty sensitive, not from the hearing 19,000hz perspective but from the apparent loudness I hear, and I prefer to wear earplugs at concerts like that. (I sure wish I’d had them when I was stuck with three Pez Band sets in a small club.) The levels I remember hearing through the plugs seem within the Super 12’s grasp. I admit I am just not a 125dB man.

But give me a live gig with a band that does not have everyone who was there and sober saying the next day that they were too loud, and I can do that. That would be amplified rock to a six piece Jazz combo going full tilt to of course recorder music. I have not tried them on Romantic era large orchestra recordings because I don’t enjoy large orchestras playing that stuff, so I can’t answer that one. They do sound very convincing playing a 66 piece, very noisy Jazz orchestra. I'm not saying the sound levels are the same as at my seat at the concert, but they are as loud as I am comfortable with at home. Any louder and I want to turn it down, and that seems reasonable.

One thing they would not do well with is the frat party I mentioned. Dance music tends to be played much more loudly than music where we sit down and listen to it. It works on the body in general and the feet in particular, almost like the ears are just a means to the end of moving the body instead of the spirit. It is really not about listening. Again, I personally have no interest in this.

Bottom line, I am a good candidate for the Super 12’s because of how I like to listen as much as what I listen to. Different strokes for different folks for sure. Do not, however equate Full Range with limpid sound levels and recordings. The Super 12’s are dynamic as all get out. They are not capable of insanely loud. While not being able to play nearly as loudly (max SPL - and remember JBL warns those levels are dangerous), they are as efficient as the biamped 4345’s. They will fill a reasonable sized listening room with great sound at volumes too loud for casual listeners. Like I said, I don’t listen in a closet, I turn it up until it sounds too loud if I turn it up any more, and it sounds like John Coltrane and his quartet are spread out right in front of me, playing live up close and personal. This is not for the faint of heart. Less than one watt powers them nicely, very nicely, and it takes in excess of seventy watts to fry them. That makes them, relatively, loud. And clear as a bell. Imaging is better than most people will ever hear.

By the way, if a guest really wants more sub 40hz bass I turn on my sub. I'm no purist, I just like to listen to my music. A subwoofer doesn't muffle the Full Range magic at all.

Clark

[Mr. Widget]

By the way, if a guest really wants more sub 40hz bass I turn on my sub. I'm no purist, I just like to listen to my music. A subwoofer doesn't muffle the Full Range magic at all.Ah the bass... I was listening to a contemporary recording through my system the other night at a very moderate level, probably peaking at 85dB or so. It wasn't connecting for me. I figured I was tired and decided to pack it in. As I turned off the amps, I realized that the subwoofer amp hadn't been turned on. While it is subtle enough when it's on that I didn't notice it was off, especially at this lower volume, having the full spectrum reproduced does matter. After my discovery, I quickly turned everything back on and listened to a song with the full system running and all was right again.


Widget

[Ian Mackenzie]

http://www.soundlabsgroup.com.au/c/Kits-Fullrange/Fullrange.html

This is a link to some properly engineered full range kits.

Cut it and slice it any way you like..there is a market.

If you look at the concept of the helper woofer and understand the engineering considerations of a very low mass cone and a very delicate VC its make a lot of sense.

Seas make a very good driver with a concentrically mounted tweeter in the main pole piece.

If you did your home work and added a sutable woofer with an electronic crossover it might be termed a poor mans Tad R1.

I dont think blowing you head off with alot of power and serious cone area has not got a lot to do with high fidelity sound reproduction. Most of the time they are doing it because they are not getting the detail and resolving power at lower levels so the brain says make it louder so I can hear it.

What they dont know is most of that really important information is contained in the First Watt and people of becoming aware of that with the resurgence if small but very high quality amplifiers

What I am saying is with some nous there are work arounds for the apparent limtiations of these types of drivers. There are some interesting methods like this design that approaches a line array are low frequencies and converges to a point source at high frequencies

http://www.soundlabsgroup.com.au/p/V-5941/Quadro

in tumultuous orchestral bursts the QUADRO was firmly in control. (...) VISATON's QUADRO cuts an impressive figure both acoustically and visually, it loves dynamic input and will forever remind its owner how pleased he can be that he did not buy his speakers from a department store


Here is another interesting approach:

http://www.soundlabsgroup.com.au/p/V-5988/Solitude

This speaker can cope with volume, has good bass response, is an unbelievably homogeneous loudspeaker with powerful all-round capabilities and a musical talent all of its own. The Solitude is technically and from a sound point of view light-years away from the fluffy mush produced by so many boring three-way boxes.

If I could afford it I would buy a pair of Feastrex drivers tomorrow.

http://www.feastrex.com/d9xfamily.html#

They are literally hand made and some of their design and manufacturing techniques rival that of JBL and Tad. At a cool $6000 a pair they are by a long shot the best true single full range driver currently in production. The 9nf weighs 8.5 Kg! The field coil drivers are way more expensive.

JBL no longer made a full range driver like the LE8T so there is probably very limited appeal for those who are in awe of big drivers and big boxes.

We all have a reasons and preferences..there is no best way

Ian

[Mr. Widget]

If I could afford it I would buy a pair of Feastrex drivers tomorrow.

http://www.feastrex.com/d9xfamily.html#"With the field coil drivers, changing the power supply can affect the sound just as much as changing the amplifier. Varying the voltage applied to the field coil can also have a huge effect on the sound by changing the damping of the driver, allowing the user to achieve a wide range of effects with every type of enclosure from horn to open baffle. The user can obtain a huge degree of freedom in creating his own sound."

That sounds like a variable nightmare to me... you may be able to really dial in a system, but since most people can't even set up a graphic equalizer properly, I can imagine some pretty frustrated audiophiles.

I am sure they are well built and they certainly are purdy.

Widget

[Ian Mackenzie]

I would imagine that to be a very useful means of modifying the driver characteristic. The alternative for fixed magnet design is a Current Source type amplifier as done by Nelson Pass.

Obviously some technicial understanding is required but the relevent forums for these types of drivers are better supported than the likes of what we see around here.

Of course if you cannot afford any of this there is no need to get too excited.

ian

[Ducatista47]

Ah the bass... I was listening to a contemporary recording through my system the other night at a very moderate level, probably peaking at 85dB or so. It wasn't connecting for me. I figured I was tired and decided to pack it in. As I turned off the amps, I realized that the subwoofer amp hadn't been turned on. While it is subtle enough when it's on that I didn't notice it was off, especially at this lower volume, having the full spectrum reproduced does matter. After my discovery, I quickly turned everything back on and listened to a song with the full system running and all was right again.
Widget
Widget, I was surprised that your main system would need a subwoofer for music. Am I correct in assuming that the "contemporary recording" contained synthetic bass tones, or perhaps a well recorded stand up bass or grand piano?

I remember some time back you and I being on the same page about large monitors not needing a sub for playing music (as opposed to home theater use). I may be behind the times, but the systems you mess around with are usually more than capable in the bass department. I do find this fascinating, though.

I know what you mean about the very bottom being subtle but important. I do actually tend to leave my little sub auto on - it comes on when my main amp gives it signal and goes to sleep after a while with no activity. Super 12's are strong to 45hz, so the 10" sub takes it from about 42 on down. It is turned down about as far as it can be and still make noise. I can't hear it directly so much as notice a difference. It doesn't hurt the imaging as tones that low tend to lack source direction. The 4345's, on the other hand, are flat to 30hz where I cut them off as JBL suggests. Since I don't feel I'm missing something there without a sub, perhaps it is from 28 or 30hz to wherever a system gets weak that matters.

Maybe it is not only Full Range that needs "helper woofers?" Maybe it takes a 2245H to get a pass?:blink: If bass is king to that extent, I see why JBL has ruled bottom end for so long. Not a bad strategy.

Clark

[Ducatista47]

Ian, those are interesting systems. Having kits available may be an idea who's time has come.

I notice all the drivers are 20 to 22cm, about 8 inch. The Feastrex cones look very much like Lowther cones, probably not a coincidence. One great thing about six and eight inch Full Range drivers is their really superior imaging when not mated to horns, like in the Omega line. They image even more sharply than the (12 inch) Super 12's, which are already great that way. Closer to a point source, I guess. It is true that the stereo effect we rely on is not really the same as the incredibly complex mixing of the sources in a live room impinging on our two ears, but it works for me when the soundstage is this good. Unfortunately, the eight inch drivers need bass help at higher frequencies and that bass may be a bit directional, softening the imaging a bit.

I also notice all the 8 inch drivers have tiny 1 inch voice coils. The Super 12 has a 2 inch. I suppose JBL would use a 3 inch for a light 12 inch cone. The LE8T used a 2 inch and a huge magnet, typical JBL.

Steve Schell has said he doesn't use the field variability as he is employing horn systems, but I bet he knows a fair amount about it or knows someone who does. Perhaps he might be able to chime in here. http://audioheritage.org/vbulletin/showpost.php?p=126115&postcount=13

Great observations and links, Ian!

About Nelson Pass's current source amps, I would love to have the time and money to build a First Watt F2. Maybe someday. It is one solid state amp I am really curious about, being designed (like the F1) specifically for Full Range. I think the F1 would be beyond me, and perhaps too unforgiving of sources and front ends.
http://www.firstwatt.com/products/f2.htm
http://www.firstwatt.com/downloads/f2_om.pdf
http://www.firstwatt.com/downloads/F2-service-manual-sm.pdf

Clark

[Mr. Widget]

Widget, I was surprised that your main system would need a subwoofer for music.My system is sorta kinda like a 4345 except instead of having a 2245 come in at 290Hz I have a Sub1500 come in at ~50Hz... my point was that many full range systems don't really do much below 40 or 50Hz... and you can get used to that. I just find it missing... especially on newer recordings.

Widget

[Tom Brennan]

A pal of mine plays around quite a bit with single drivers but always augmented with subs. Some sounded pretty good and some wretched, like with any other approach I reckon. He often uses simple cardboard open baffles.

http://i254.photobucket.com/albums/hh92/Irishtom29/FostexonJBLopenbaffle.jpg

http://i254.photobucket.com/albums/hh92/Irishtom29/FostexandVOTs.jpg
The best single drivers I've heard were Fostex FX-200s. But they're no longer made. I've heard some pretty good Lowthers too.

[Mr. Widget]

He often uses simple cardboard open baffles.It's good to see he is using the correct type of cardboard. ;)


Widget

[Ducatista47]

If this thread is of interest, the first six or so pages of this paper may make good reading:http://www.firstwatt.com/downloads/cs-amps-speakers.pdf

A sample: "Most interesting are the full-range high-efficiency drivers that deliver the goods with only a watt or so. It’s a big design challenge to produce a good sounding full-range acoustic
transducer with 100dB/watt efficiency. When it is properly achieved, you get a wealth of
detail, exceptional dynamic range and a sense of musical “liveness” that you don’t often hear
elsewhere."

This one is also good:http://www.firstwatt.com/downloads/cs-xover-networks.pdf

I can't help but think that these current source ideas may have wider application for high efficiency drivers with light cones and voice coils, no matter what they are called. JBL has specialized over the years in powerful motors and precise gaps. Perhaps voltage source amplification is not the best way to drive them.

If these look interesting, here is the source page of these and other articles. Notice Phase Coherent Crossover Networks. :) http://www.firstwatt.com/articles.htm

This entire field has finesse written all over it. I know a lot of us drift towards finesse reproduction as we get older and more experienced.

Clark

[Ducatista47]

In the last post I alluded to JBL's basic motor design being well suited to high efficiency in general and full range in particular. OK, it was between the lines but I was thinking it. The reason why it is senseless to speculate about this is that a new cottage industry would have to form to bring it to fruition. I believe many eight, ten and twelve inch motors would make great full range drivers, but coil/cone assemblies would be required to complete the speakers and they don't exist. This would require an after market entrepreneur, like John Wyckoff was, or someone who could produce cones themselves.

There are numerous reasons why this would be a good idea.

* What happens to nice old JBL drivers when their surrounds rot away, or their cones or voice coils are damaged or old and tired? We all know a recone is a better answer than than a re-surround. We also know that a motor can be reconed with a different cone to make it essentially a different speaker. If the cones were available, these excellent motors could become something else entirely, like for instance a high quality, sensitive full range driver. High quality design and construction, powerful magnetic assemblies and precise gaps are needed for this. If this isn't JBL I don't know what is.

* JBL cores are not expensive because the seller knows how expensive a full recone is. I can buy 2245H cores anytime I look. I paid $90 last time and that was high. Perhaps smaller cores would be even less.

* The older designs that the more senior members here keep reminding us are not as good as the new stuff would be at no disadvantage here. Cooling a watt or two needs no technology, and all the improvements to combat power compression, the danger of demaging Alnico, and the like are not needed. Anything designed this well will be pretty linear at these power levels.

* The cast frames are overkill for a speaker that usually plays at a watt or less, but they are a nice touch and frankly we are the sort of people who appreciate this kind of engineering for its own sake. This attention to detail guarantees the needed precision and the quality of the entire piece.

* With pleated surrounds and a diet of low wattage drive to look forward to, the initial cone jobs will last a lifetime and then some.

* Hemp cones are now available. I keep reading how they are an improvement in almost every way. A new cone design could use hemp.

* Someone out there is already making a product similar to this, so it could be outsourced. (Hasn't JBL outsourced this, like forever now?) Omega probably does not make their own full range hemp cones. Someone does. That means low production numbers are economically feasible.

* It seems the days are numbered for factory JBL cone kits. I can't stand the thought of these ending up as paperweights (well, doorstops and pressing weights for woodworking) or in landfills.

* Our favorite JBL motors could be driven by today's super high fidelity tiny amps, like triode designs or the Nelson Pass First Watt offerings.

Clark