Crossover questions

Well, the fact is that I am in the unlikely situation of my girlfriend WANTING a second system in my house. When we remodel the family room, she wants an A/V setup in there. That includes buying a nice(Lovan, VantagePoint, etc.) rack, and filling it with things like a tv, vcr, dvd player, amplifier, etc. She has been really into looking at racks and speakers lately. So, I told her that I can build a better pair of speakers than would ever be in the budget. I used to play around in this hobby a fair amount, but those days are a few years in the past. Now, I am faced with designing/building a pair probably in the next six months. My tastes, opinions, and views about audio have changed a lot since my speaker hobby days. Mostly in the realization that less is more, and that tubes appeal to me. That is why I am approaching all the great members of this site with my questions. I will build a pair of speakers that are definitely tube friendly. Maybe even take that to the next level. Very easy to drive. I think I will probably go with two midranges, because I am thinking about wiring them in series. The reason being the impedence would be doubled. Has anyone ever designed such an arrangement? I will run them flat out, with no capacitors, inductors, or resistors in the circuit. Moreover, I am considering wiring the entire crossover in series. Does anyone have experience in this area? I recognize that this was the way things used to be done a long time ago, and there aren't many of the proponents of the design around these days(other than Bud Fried). But everything old is new again. I do see renewed interest in series crossovers, so want to at least consider it. Bud is local to me, so I am thinking about contacting him. However, his designs were anything but easy to drive. I am also pondering whether or not I should use additional woofers on the low end. If I do that, I will equip them for biwiring, and may have to use a beefier amp on the bottom end. My most profound thank yous to all in advance for any opinions offered, Joe.
Check out the article by Harvey "Gizmo" Rosenberg in the August Listener about electronic crossovers and hooking speakers directly to your amps. Not exactly what you are talking about but an interesting approach that I intend to try. He also has a web site This guy is a little, well maybe way off the wall, but he always has interesting ideas.

If you aren't going to use any capacitors, inductors, or resistors in the circuit, how do you intend to construct your in-series crossover?

I agree that less is more. I recently upgraded to a high end turntable with the money I got from my monster tube amps and 3 way megabuck speakers, and switched to SET amps and efficient 2 way speakers. This is definitely the most musical system I have yet assembled. Good luck with your project.
Joe, how do you feel about horns ? They meet all of your criteria and then some. Highly efficient, easy to drive AND very dynamic. This would work with either a tube audio set-up or a "punchy" HT set-up. You can easily get away with a single mid and tweet and use double woofers for "HT impact" and to keep the sensitivity relatively even across the band. Something along the lines of a Klipsch Heresy with a built in sub or double woofers might work very nicely for your project. I was thinking about doing something along those lines myself sometime in the future. As to the specifics in crossovers and doing the "series thing", you might try contacting Clayton over at the Asylum. I know that he has played with Series crossovers and is normally more than willing to share his knowledge and experience. Hope this helps. Sean
My budget for building speakers is always based on the quality of the listening room first.
If there is another person involved, such as your girlfriend, her expectations need to be well understood.

You wrote about building a "pair of speakers" but an A/V system requires five speakers and one subwoofer. If possible, the five speakers should be identical. At the least, all three front speakers should be identical and oriented the same way (no hoizontal center speakers and vertical left and right speakers) for optimum fidelity.
The typical woofer-tweeter-woofer center speaker
sitting on top of a TV set in a horizontal orientation is a compromised (for better appearance) design placed in a less than optimum position. (The center speaker provides up to 2/3 of the sound energy in a typical film mix (excluding the subwoofer), so its design should not be compromised to make it 'look better' on top of the TV set).

Magnetic shielding will be a concern too.

To ensure your project is a success, I suggest thinking about three important subjects first:
(1) Room size and dimensions:
(For example, why waste your energy building five high quality speakers for a "low quality" small near-square room -- this type of room would also have a strong negative effect on subwoofer bass frequencies)

(2) Room acoustics:
Will you be able to treat the room so you get the less reverberant/dryer acoustics needed for A/V?
(Two channel stereo works best in a more reverberant than average room -- A/V does not).
Directional speakers (controlled dispersion) are also a plus for A/V, while wide dispersion speakers are best for two-channel stereo.

(3) What does the girlfriend REALLY want?
Women often are not as direct as men in their
For example, is she thinking of five very small speakers and a small subwoofer hidden in a corner
or behind the couch?
- Is the appearance of the speakers more important than the sound quality?
- How flexible is the "budget"?

One question whose answer would clarify your post:
(a)When you wrote "two midranges", did you actually mean two "midrange-woofers" as in an Woofer-Tweeter-Woofer two-way design? That's what I assumed.

One comment on running woofers "flat out" (no crossover):
This is the most common arrangement in loudspeakers today (crossover = one capacitor and maybe one resistor) but almost all are cheap
speakers and don't sound very good.
-- There are a few exceptions:
I really enjoy my own EPOS ES-11 satellite speakers with no crossover at all on the small woofer. I recently enjoyed an audition of the $500/pair Triangle Titus speakers with a similar no-crossover woofer. The woofers in these speakers were especially designed to be used without crossovers. Without crossovers, MOST woofers available to DIY speaker builders would provide too much mid-range SPL relative to bass frequencies (no baffle-step compensation) and a rough frequency response at the high end of the woofer's frequency range.

I'm also not in favor of wiring woofers in series
because back-EMF from one driver will modulate the voice coil of the other driver. I don't know if this is audible -- maybe it's just an old wife's tale -- let others comment on whether this makes an audible difference.
Thanks for all the responses. Sean, I think I will contact Clayton for his expertise and opinions on series crossovers. I will probably also get in touch with Bud Fried. Herman, I will check out Gizmo's ideas. I have considered horns, but have never really fell in love with them. I do have a pair of horn speakers in my living room that my father built in the mid 1960's. They are exactly as you suggested. The sound of them is pretty good. Perhaps, I will give higher quality horns more consideration.

I am not at all interested in a 5 channel HT setup, and expressed these feelings explicitly to my girlfriend. She has no problem with this, and basically just wants to have a nice looking setup in the family room. One where we can watch tv and she can sing karaoke. Whether my woodworking skills are up to the challenge(to make something "attractive") is the question. Her reasons for wanting a good amplifier/speaker arrangement are completely to appease her boyfriend, who happens to be waaaayyy too serious about audio.

As far as the excellent speaker questions that were raised, here are my rapid fire answers(sorry for my lack of clarity in the initial statements)... I was stating that the midranges(or mid/woofers) be run flat out(no caps, coils, or resistors), and wired in series in an overall parallel crossover network. Wiring the entire loudspeaker in series would preclude me from keeping components out of the path of the midrange drivers. Rgreene2, Triangle(glad you mentioned them) is one of the speakers(along with Eggleston and personal experience) which have proven to me the benefits of running the midrange or midwoofer with no crossover components in the circuit. In my parallel crossover approach, the tweeter would have a film and foil capacitor wired on its positive leg, and a resistor(if needed). As far as woofers(in the strict sense of the word) go, I am still undecided. They suck a good deal of current. I may just build these speakers with nothing larger than 6.5" drivers. If I later decided that I really needed to have that last octave, I could go with a pair of subwoofers.
Still have a lot of thinking to do... Things like do I use a REALLY dead cabinet, or more loosely damped(that everything old is new again thing)? I'll decide that after I figure out the crossover, but have always felt a dead cabinet was the way to go. Double thick walls(featuring MDF and plywood), with a layer of something between them(Swedak, viscoelastic, or other polymer), corner braced internally, and BlackHole 5 on the inside walls.
Joe, apply your "deader than a door nail" speaker cabinet theory to the horns / horn bodies on your dad's speakers. Keep in mind that some horns have some type of screen / mesh "diffusor" in the throat near the driver. If that is the case with those specific speakers, remove them. Most of the glare / ringing that you hear from horns can be directly attributed to the resonance of the two culprits i just mentioned.

As to using "Black Hole" (which is quite expensive in large quantities) for damping / deadening / mass loading, try using "damping sheets" from Parts Express. MUCH, MUCH cheaper and it will do at least 80% of what you're looking for. I'll snag a part number later should you or anyone else need it. Sean
Thank you Sean! I will think about horns in a more thorough light. The cabinets of my father's speakers(horns with cone woofer), while excellent for their day, can be improved in several ways. Also, the quality of the passive parts(coils, caps, resistors, and wire) have improved quantum levels since those speakers were built. I will also take your advice about the "diffusors" to heart.

You are quite correct about the cost of BlackHole 5. I once made a few "sound boxes" at my previous company. We manufactured EL(electroluminescent lamps), for use in cell phones, pagers, night lights, etc. The whole technology is simply a capacitor that lights up when supplied with AC voltage. There was a lot of noise generated via the AC voltage(coming from the inverter)/lamp. My job was to get rid of it. I looked into anything I could. The sound boxes were just basically speaker cabinets we built(minus the speakers, but with a window to view an inserted SPL meter), which insulated the lamp/meter from the ambient noise of the plant. Got lots of wonderful experience with sound insulation materials. Things like acoustic foil, SoundCoat, foams of every sort, viscoelastics, rubbers, silicones, polymer formulations I developed(applied via screen or pad printing). In the end, the best solution was to simply screen print a third electrode(using my carbon resistor paste) which served as a "shield".

The experience of building those boxes and insulating them(with foams, SoundCoat, foils, BlackHole Pad, BlackHole 5, Swedak, etc.) was invaluable in teaching me about quieting down a box. Materials were free(either sample or out of the company's money), and I was being paid. BlackHole 5 proved to be an excellent product(I like the viscoelastic/multiple foams combination), and we did end up buying a bunch.

To be honest, I can(and probably should) build that BlackHole 5(or better) using viscoelastic sound panels(probably the same as the sheets you are getting from PartsExpress), and two kinds of foam(from Foamex or whoever) for a fraction of what Orca's retailers charge for it. Even incorporate some acoustical foil(very effective stuff) in the my homebrewed insulation.

Now I get to use all of that information! Speakerbuilding is an immense subject, and no one has all the angles covered, but it sure is fun to play this game. If you are going to be undertaking a similar project in the future, it would be great to bounce a lot of ideas off each other. Again, thanks for your help.
Sean by the way, I just came across a thread on Tweaker's Asylum from 'Clayton Oxendine' regarding a series crossover question(via web search on "series crossover"). So, I now have found at least one person in the world who has knowledge of this mostly forgotten technology. Again, thanks for your help in steering me toward this person!
Trelja, e-mail me and we can discuss speaker design sometime, if you like.

My opinion is that series crossovers aren't a "forgotten technology", it's just that they are difficult to design, and are very unpredictable (very difficult to model with computer programs). I believe Joseph Audio's legendary x-overs are series, and his are supposed to be the steepest in the industry. The Stereophile review measurements confirm it, too. You can bet he hasn't "forgotten the technology".

I have two suggestions for you to check out:

First, if you like connecting speakers directly with no crossover, consider building a system with Fostex full-range drivers from Madisound (similar to Lowther, but much cheaper). At least visit their site and take a look at the drivers, and their flat frequency response. I've never heard them myself, but I bet they're worth the money, wheras the Lowthers are insanely expensive!!

Or second: Consider the speaker kit. They connect a bunch of aluminum coned midwoofers in series-parallel, use a high sensitivity tweeter (looks like a Focal clone), and the sensitivity is around 95 dB. It's an easy load to drive.

If I didn't already have several speaker projects going, I'd have bought the Bottlehead one immediately. I'm actually trying a project of parallel midwoofers. it will be a more difficult load to drive, but with these particular ones, it might work. I hope to use two tweeters in parallel per channel, and the sensitivity should be around 96 1w/1m. The catch is that the cabinet will be quasi-dipolar, and I'll augment with whatever powered subwoofers I have on hand...currently the Sunfire.

I just bought some Infinity Emit ribbon tweeters from for only 40 bucks a piece, and they're simply incredible! I bet they're 99% of the performance of the Raven R-1's, at least until you get closer to their thermal limit.
Noquarter, thanks for your input. Last night I visited a great website(sorry that I don't remember it now) that dealt with series crossovers in a very strong manner. Featured prominently were John Risch, Clayton Oxendine, Bud Fried, and others. Lots of good information. Including things like zeta(the important thing in series crossovers) calculators, and some real world projects. I am sure that some of the information I will relay here will be incorrect; it was a tremendous amount of stuff to drink in in a very short time.

Zeta is one of the determinants in how quickly the crossover rolls off the driver(???, I kind of forget now). It seems that a zeta should range between 0.7 and 1.2+. At 1.0, it is more analogous to a parallel network. A zeta of 0.7 is said to make the speaker much more upfront in sound(a good rocker's speaker), while 1.2 is more laid back(more like an audiophile speaker - "Boston Bland?").

A two way, 1st order series crossover is very simple to build. In fact, it uses the same values for the cap and coil as the 1st order parallel network. Obviously, how they are connected is different. I do wonder what a series crossover in my speaker buys me. Running the mids flat out would obviously save me the cost of the coils. I am not sure if the sound would be improved over running it with nothing in the circuit. I am also not sure the sound would be detrimentally affected by the wiring of a cap on the positive leg of the tweeter's circuit(ala a parallel topology), as compared to the way driver's are connected in the series crossover configuration.

Wiring in multiple midrange drivers is something that the author has described(in several examples), so he has that question of mine covered. One of their rules is to use drivers that feature a very broad operating range. I did a little thinking of the midrange, and my desire is for one that is very efficient. The Focal Audiom 7K comes to mind. About 97 dB sensitive, with an 8 ohm impedence. I remember it being pretty flat from 100 to 10000 Hz. Drawbacks are the lack of bass response, and extremely high cost of this driver. I believe they also manufacture a driver that gives up 1 dB of sensitivity at about a 40% cost savings. I really like Focal mids and woofers; finding them punchy, dynamic, and clean.

Another critical factor in the series crossover are the coils. It is important to get as low a DCR as you can afford. AlphaCore Goertz were recommended over Solen and North Creek. If I remember correctly, the rate of rolloff is also related to the DCR.

I will look into the Infinity tweeters at the website you listed. My concern with them is their sensitivity. Do you know that offhand? I presume it would be much lower than that of the Raven. Not that I have decided to use the Raven, but it is on my short list.
I doubt it's much lower. To my ears, it's about 93 dB, wheras the R-1 is supposed to be 95. Speakercity also have the Hi-Vi Research RT-2 Ribbons close-out priced for only $31 a piece...I bought a pair of those too. They aren't flat though, and will need a gradual rolloff below 10kHz to bring the top octave up. By contrast, the Infinity Emit seems to have nearly the same dispersion as a one inch dome, and even more surface area. A pair of the Infinitys in parallel might be a better approach than a single R-1, at least where money is concerned (i.e., more surface area and higher efficiency). To my ears, it's as good as the circular ribbon Genesis uses, and that's saying a lot!

If you're wanting several midwoofers in series-parallel, then of course your cost will go WAY up. I still would like to suggest the Bottlehead kit. You could even modify it by using a different tweeter, like a Focal dome (or that pricey new one Kharma uses), a Raven, a Fostex, an Eton, or whatever. As is, though, I bet it would more than suit your needs.

If you have more money than sense, you might want to buy a pair of the new Accuton DIAMOND DOME tweeters, for $2500 a piece!! I bet they are just killer! Supposed to be pistonic to 100 kHz!!

Actually, the 8 AWG North Creek air coils have the absolute lowest DCR of any inductor on Earth, and DCR is always a direct function of the cross sectional area of any conductor. The main advantage that Solo's or Alpha Core's foil-coils have, is in reduced skin effect, since the entire conductor is a ribbon, so it conducts electricity entirely on its "skin". However, their largest ones are only 12 AWG, so their DCR is radically higher than that of North Creek's 10 or 8 AWG air core coils. Solen even makes 10 and 12 AWG heptalizt coils that are supposed to be magnificent.

In one of my projects, I went from a 14 AWG Solo CFAC inductor (identical to, and predating, Alpha Core), to a 10 AWG North Creek, and every aspect of performance improved (that driver is a Dynaudio 15W75-04).
Lots of good dialogue here Noquarter. Thank you. If you are interested in seeing an interesting site on this series crossover "thing", please go to

It may just keep you busy for a while.

You are correct in what you say about the North Creek coils. It is just obvious that their 8 or 10 gauge coils would have a lower DCR than AlphaCore Goertz, whose largest are 12 gauge for copper, 14 gauge for silver. Don't know why I went along with their statement. It should be more than apparent. Perhaps they offered this up before these North Creek coils were introduced. Not sure when that was, but the last time I bought North Creek coils(1996) their largest wire gauge was 12. I am not a fan of the Solen heptalitz coils, I find North Creek much better sounding. And the Goertz would give a sound of another color, whether it is preferred is a matter of personal taste. I will need to check out North Creek to see how expensive these larger gauge coils are. Again, by running the mids flat out, I can save that expense.

I know that I prefer the sound of the mids without a coil in the circuit. Presuming that the driver is of the requisite quality and robustness, it is a no lose proposition. I would like to hear an argument as to what a series network could offer over having nothing in the path of the midrange.

I would not install more than two midranges in each speaker. As you pointed out, the cost of going crazy in this area adds up fast. I am leaning towards the two midranges, despite my liking the time alignment(one midrange) my Coincident speakers feature. Their sound has more than sold me on the arrangement.

Accuton drivers are not new. I first came across them in the early 1990's. While I didn't spend a lot of time with them, I can describe the sound as very smooth and natural. While pricey, they are not as expensive as Raven. I would not use Accuton drivers in this project because they are lower in sensitivity(usually 88 - 90 dB/2.83 V), and are not physically robust. I used to work with alumina(electronic substrates, paste, and I also used to tape cast it), and while very hard, it is very brittle. I have seen these drivers shatter rather easily in a speaker that was involved in a move.

In researching the EMIT-B ribbons you recommended from, I found the sensitivity was too low for this project @ 90 dB/2.83 V. Price is good at $40. What do you think of the sound? I have not been around an EMIT driver since 1988.

The Ravens are available in sensitivities of 96 and 98 dB/2.83 V. Very high, but they are very expensive. Not sure if I want to put this kind of money in a speaker when I will be doing the cabinet work myself. While I have no problem with the construction of the box, I have never done any finishing. If I am going to build an expensive speaker, I kind of think it deserves the "living room" look.

I will also look into Cabasse drivers. I once helped a friend in a D'Appolito project using these drivers. They feature some highly sensitive drivers in their line. Sound is fast, and clear. Maybe not as laid back as I might want. We'll see. Following along Sean's recommendation, they offer some horns, which I should investigate. 108 - 110 dB/2.83 V sensitivity. Interesting.

Needless to say, the diamond domes are out of the question. Maybe Liz Taylor would be interested...

I will check out today. Thanks for steering me to their site.

My only listening of Fostex drivers were in a speaker that had no grunt to me. Kind of shallow. Lively and able to play loud, just that I prefer a little more "blood and guts" to the sound. Maybe I am selling them short. Have you heard them in a better light?

I am on record at Audiogon of not being the biggest fan of Focal tweeters. They can play loud and clean, just hard on my ears. But, I have really been impressed by the sound of Osborn speakers, which use all Focal drivers. When driven by more sedate electronics, such as Electrocompaniet, I have to admit the sound is first rate. Their mids and woofers are right up my alley, however. Available in high sensitivity or high impedence versions. So, that is why I will probably go with them or Cabasse.

Again, this is a wonderful dialogue. Something about the speakerbuilding hobby that I can never get tired of. Thank you!
Well, good luck in your project. I'll check out that iprimus site.

I never said Accuton was new; I said the Diamond dome was new. It will be interesting to see which manufacturer uses it first.

The sensitivity for the Emit-B seems higher than 90dB to me. The sound is fantastic imo; far more detailed and dynamic than I was expecting. It's a modern unit, with Neodymium magnets, so it's bound to ouperform those Infinity units you heard in the 80's.

Also, the published sensitvity for the new Raven R-1 is only 95 dB, the higher sensitivity is for the previous models (now discontinued). I think a pair of the Emit-B's in parallel would equal or exceed that sensitivity. Keep in mind that neither of these small tweeters will work below 3kHz.

As I've said before, if you absolutely want to run a midrange driver "flat out" you should consider a fullrange speaker like a Lowther or a Fostex. I've not heard the Fostex drivers, but their specs look more than adequate for their price, even a match for the Lowthers. The 8 inch model has nearly 100 dB sensitivity!! A series crossover isn't quite the same thing as running a fullrange driver with no crossover at all, imo.

Have you looked at Madisound's site, under Fostex drivers? Also, their ribbon tweeter looks about as good as the Raven R-1, and the Fostex one is only around $100...half the price.

I had thought that your goal was to throw something together for your secondary system, and to experiment; I didn't realize you wanted it to be a "statement" project. Those can be difficult and time-consuming...and let's face it, neither of us is a world class designer.

I, too, am no fan of Focal tweeters. Problem is, if you want to use only one tweeter, and decide you'd rather have a dome than a ribbon, the Focals are the only ones with high sensitivity, without horn loading.

The problem with using compression drivers and horns, is that you wind up padding them way down to match the lesser sensitivity of the midwoofers, so a lot of power gets wasted in the crossover, and I'm not sure it's even possible/ideal to use series crossovers in such an application.

I think you'll find, that unless your living room exceeds perhaps 7000 cubic feet, you won't need a speaker higher than 100 dB sensitivity (even with only a 3 watt amp)...and in any case, without the proper room treatment and placement, you'll hear more of the room's echo than you realize, imo.
Thank you Noquarter. You have graciously provided more information than I could ever expected. I am endebted to you. If you don't mind, I will get into contact with you at some point outside of this thread to further discuss some things.

You are absolutely correct in raising the issue of this being a secondary speaker project or a "statement". To be honest, I easily fall into this trap. I go way overboard. A very negative byproduct of my love of the speakerbuilding hobby. It is by far my favorite facet of audio. In fact, spurred on by my thinking of the past few days and your assertion, I discussed this with my girlfriend last night. This was supposed to be a secondary speaker. I really should just buy something along the lines of 4 Vifa 6.5" midranges and 2 Vifa D26 tweeters. Run the mids with nothing in the circuit, and connect a not overly extravagant film and foil cap on the tweeter leg. Throw them in a reasonably well constructed box, wire them up and call it a day. Perhaps, I should revisit that for this project.

But, I have still haven't ruled out doing something where I can build my speakerbuilding skills/experience further...

One of the higher sensitivity Ravens I was referring to was the Raven R-2(there is another). If I do decide to use one, hopefully they have not been discontinued. I did hear the Raven tweeter in a few newer designs from Acarian systems, and my initial impressions are quite favorable. If this tweeter really can offer me this detailed, yet smooth sound, coupled with this level of output, it is definitely something that would be on my short list.

Good points on the horns. That is actually what I originally envisioned. Aim for a sensitivity from 92 to 95 dB/2.83V.

As far as the Fostex drivers are concerned, I did visit the Madisound site. While they look good on paper, as I previously stated, my real world experience with them was in no way favorable. Yes, their sensitivity is high, and their operating range more than extremely broad. Just that if I am going to build or buy a loudspeaker, it better not sound like that. Able to play lively and loud, yes. But to my ears, along the lines of the way a clock or table radio sounds. No sock or punch. AT ALL. My hope was that you would have also had heard Fostex. To tell me whether what I heard was just a poor execution of the driver, or an affirmation of this being what it sounds like.

The fact that we view Focal tweeters in the same light shows me that we do think in parallel ways, at least in this area. And, also in our belief that a driver with no crossover should be better than one in a series network.

So far, the only speakers I have heard with the series crossover fresh in my memory is Roman Audio. Very, very impressive. Yes, this hyped up, patented DiAural crossover is actually just a series network! Just that it contains no capacitors. SonusFaber has supposedly used in the past with a tweeter, so how enforceable is the patent?

I also heard Fried a lot in the past, but would need to hear them with my current ears/mind, and with the type of gear I use.

Again, thank you.
You are quite welcome. I've always felt that the problem with "highend audio", is that there aren't more folks like us. I have to laugh, when I think of all those consumers that take loudspeakers and room acoustics for granted, and instead pay more attention to "tweaks", like gold-plated titanium rollerballs, etc.

I look forward to hearing from you in the future.

Did you happen to hear that Alon Statement speaker? it's the only one I'm aware of that uses the Ravens, they're the smaller R-1, and it uses 6 per channel I believe.

The speaker I'd like to hear, is that Impact "Airfoil" bending wave model...supposed to be a new take on bending wave drivers, uses them in a line array, fullrange down to about 100 Hz.

Does the Coincident speaker model you have not use the Seas Excel magnesium coned midwofers? I thought they all used those magnesium cones...the thing with them, is that you can never get rid of that ringing, even with an infinite slope crossover. It's just that it's essentially inconsequencial in the final speaker, since the ringing still is mostly focused on-axis.

Metal cones do have an efforteless controlled snap to the sound, I have to admit. I own an aluminum-coned Seas, for yet another project. The corresponding magnesium model rings somehwat louder than the aluminum, though...but that solid copper phase plug in the Excel versions sure looks awesome.

In my opinion, the 8 AWG North Creek coils get very close to the performance of not having a coil at all. However, they aren't exactly the same, obviously.

No, I've not heard any of the Fostex line. I'm curious if the driver you heard was mounted on a baffle in a finished design, and if so, which model was it? Was it any of the current ones in production, as listed on the Madisound website? Did it use a rear-loaded horn, a front-loaded horn, or both?

I'm trying to decide which 4 inch midwoofers to get, for the tiny "monitor" project with the Emit tweeters I bought. There is an older Vifa 4 inch polypropylene cone that has an EXTREMELY smooth rolloff, and might work with no crossover: the P11WG-00-08.

I may try using this one myself, but according to the Solen catalog, it will only yield an F3 of 60Hz, and I was hoping for a tad lower.

If I can't find a treated paper 4 inch cone with a low enough Fs, I may try and use that poly-coned model I mention above. It's just that I'm getting tired of the sound of poly cones. They have the advantage one you go bigger than 6 inches diameter, but not for 4 inches diameter, imo.

All would be fine, if Audax's new "polymer chassis" line, didn't feature back plates WITHOUT vent holes for the pole piece. Why anyone would ever buy midwoofers without vented pole pieces is beyond me. And they even charge as much for this new polymer line, as they did for the premium zinc-chassied line. That just seems outrageous to me.

I own 6 of those too (they're spectacular imo), it's the treated paper version of those found in the Pipedreams. They're discontinued now, so they only sell the carbon fiber model, again as found in the Pipedreams.
Hey Trelja, i know a guy with four mid woofers from a set of Coincident Eclipse's. I think that they are relatively efficient according to Coincident's ratings ( appr. 92 or so...), easy to drive, no fancy crossovers or notch filters required, etc... They might work great for your project. I bet that he'd get rid of them pretty cheaply compared to what they cost brand new. If you think that they might work for you, drop that guy an email... : ) Sean
Hey guys, maybe we should start a club? Yes, loudspeakers and room acoustics are the first thing to take care of. I love "audio salons" who offer to come over and "evaluate" your room(because I couldn't possibly know how to set up an audio system), when they should have someone come in to evaluate theirs first. But, how about those rollerballs? Do the gold plated ones really sound better than the nickel? Kidding of course.

Sean, I remember us discussing Coincident drivers in the past. Are these the same drivers as those? From what I remember they were a Seas cone, perhaps in the P17 series. There is a chance I would be interested in them, but one of the goals of this project would be to build a loudspeaker that sounds(and is) different than my Coincident.

I am sorry that Israel didn't get back to you in regards to crossover design. From what you indicated, you felt that Coincident might be running those drivers flat out in the Super Eclipse. Any further thoughts on that?

Noquarter, my Coincident speakers are the Digital Master w/Troubass subwoofers. If you go to Coincident's website(, you can find the Digital Master in the "reviews" heading(Audio magazine, Feb 97). They are truncated pyramid(where the time alignment comes in) satellites that use the Troubass subwoofers as stands, ala Wilson WATT/Puppies, Verity designs, etc. Only they were aimed at the tube/SET crowd.

The midrange drivers are from the Seas Excel line, the P21 series(I now forget exactly which model, my apologies). A polypropylene 8" driver, with inverted butyl surround, phase plug, and according to Coincident a 5 1/2 pound magnet. Exactly mirroring your statements, the magnesium cone drivers were not appropriate in this speaker because of the ringing. Magnified in the 8" version, and even more so at this relatively high crossover point(for this size driver) @ 2 KHz. The tweeter is a silk dome. Crossover is a statement in simplicity; first order, a capacitor in series with the tweeter, and a coil in series with the midwoofer. The review's only criticism is the lack of deep bass, which is obviously not a problem in my setup as I use the(perfectly matched to the Digital Master and Troubador) Troubass subwoofers. 10" drivers in large, sturdy rectangular cabinets. The literature states that they produce 22 Hz @ 105 dB, with less than 1% distortion.

The sound is very impressive. Dark, pitch black background. Fast, very alive, yet powerful sound. More authoritative(to me) than more recent Coincident speakers. Not as SET friendly as the newer designs, however. Detail is excellent. Soundstaging is as good as I have ever come across. I have been around a lot of speakers, but these were the only ones I have ever come across that I immediately fell in love with and KNEW I needed to own. I have never again come across that feeling again, and am still completely crazy about them.

There is just something inherently "right" about the sound. Whether it is a result of the time alignment, well constructed dead cabinet, simple first order crossover, etc., or the sum of it all, it is an example to everyone in audio who thinks that the sound of the designer(via complicated designs and even more complex crossovers) can ever be better than the sound of the materials themselves. And while I may have thought I knew something about speakers, I really didn't know anything. Just go with whatever the parts offer you, stay the hell out of their way, and let them speak for themselves. That is as good as they will ever get. Another confirmation to me(it took me long enough) in seeing that simpler is better.

Your statements about the metal cones were all pointed out to me in conversations with Israel. I pick his brain as to anything he would change with the speaker. I wanted to take them as high as they would go. His belief is that the only change that can be made to improve the speaker is upgrading to the ScanSpeak Revelator tweeter("You'll think you bought a new pair of speakers"). My suggestions were the magnesium coned mid/woofer, upgraded coil, cap, and wiring(silver). He has never been enthused about any of these. I still maintain that a better coil(such as an 8 gauge from North Creek), film and foil cap, and better wiring would HAVE to make things better.

I also once asked what his opinions were about this speaker's use of an 8" midrange as being a detriment. To which he strongly disagreed, saying that the performance and speed of this driver are wonderful. That this is a favorite speaker of his, and that he would put it up against anything produced by anyone. I guess it is a bittersweet thing that his previous(very interesting) designs(cabinets and coincident drivers - where the company's name derived) are no longer produced because of the success of Coincident. Those cabinets just require too much work.

The Acarian speakers I heard the Raven tweeter was the Statement. But, also in a new smaller line(Exotica), which also feature Seas magnesium coned drivers w/copper phase plug. The Exotica was showed to me by Marilyn in a separate room(that wasn't being used) at the NY HiFi Show. I told Carl I liked the sound of the Raven in the Statement, but that $120K(?) was WAAYY over my head. Carl took Marilyn aside and spoke to her, then she told me to follow her. We talked for a while about the Raven and alnico magnets, and she made me promise to give the Exotica a thorough audition at a local dealer(in Philadelphia). At the audition I saw that the Raven held amazing potential. Well, in Carl's hands at least.

Elliot Zalayet carries so many products like this in his Long Island showroom. I used to see them when I went up there. Raven, Cabasse, Accuton, Focal, and Vieta drivers. He is a little offputting for some people, but he is really a super person to have in this hobby, very helpful and knowledgeable. 7 or 8 years ago, I asked him why these drivers weren't being used in high end speakers. His sanitized comments were 1) the companies were not as creative, and that audiophiles are not as knowledgeable(so they don't demand the drivers) as they both tell us and 2) these drivers are more expensive. Since then, basically the only drivers of these "unknown" companies that have surfaced in high end in any great measure were the Focals.

The Fostex drivers I heard were the 8" drivers, complete with "whizzer" cone. In a medium sized, vented cabinet, with no other drivers. Not a dead cabinet, and meant to be that way. A homage to the designs of the past, as these designs basically are. Pre HiFi. I kind of think these drivers may be perfect in that element. But, it isn't my taste. After hearing it, my impressions were that was what these designs basically were. A page from the 40's and 50's, when 35 wpc was astronomical. Loudspeakers needed to be efficient, and not demanding in terms of current. Bass was not in the equation(was there no power for it in those days?). The speakers played loud enough, and were not slow in the least. But, like I said, it had the sound of a table radio to me. Pretty much what people's systems of those days sounded like(such as my grandparent's stuff). Richness, if ever there seemed cloying, and not of the dynamics and punch we have come to expect from the past few decades. So, I wonder if this guy(a friend of my father) who built these speakers for his system did a poor job, or is it the Fostex? My father, who is a TOTAL bass freak(and solid state type), thinks they are the worst speakers he has seen someone put together in a long time("He should have just used 6 X 9 Jensens...").

I can certainly empathize with your search for drivers. I wish you luck in this project with the EMIT tweeters. I am also thinking I should take a flyer on them, great price. Maybe I could put together a monitor like you are also doing, and give them to my brother-in-law who NEEDS speakers in the worst way, but is unlucky in that he is married to my sister(who won't allow him to buy anything). A fun project to get the blood flowing again, nothing as serious as what you are building.

Is it me only, or do you also face these issues often? If only I could get this magnet with that cone, or that cone with that surround, that surround with this basket, or that impedence, the list goes on and on... Jokingly I say that it's just like car companies. When they come out with a new model I have been waiting for, I have to wait another 3 or 4 years before the stuff I want is available in it. Either that, or they redesign the car all over again before they get to what I want, or my tastes have moved on altogether.