The Marzemino

[cjd]

The name: It's an Italian grape variety, known for it's long growing season and late ripening. It is susceptible to fungal diseases... So, in that light, appropriate for this project. That is to say, this is likely to take a rather long time to ripen, and may find itself dead and useless somewhere along the way.

Also, there is a music reference: In Mozart's opera Don Giovanni, the titular character Don Giovanni calls out for a glass of Marzemino just before his deliverance into hell. Which is perhaps where I will be sent if I finish this...

It will be (almost) full range dipole (lower end being where it is unlikely to remain dipole). The goal is minimal driver count, minimal crossover, and ~90dB sensitivity.

It will start with some fiddling and experimentation. On my doorstep tomorrow should be some Neo8 and Neo3 planars to start the fun. I will be playing with some waveguide-ish setups here to see what can be done to improve power handling and low end response.

That's all for now. But once I found the right grape, I had to start the thread.

:Z

[JonMarsh]

The name: It's an Italian grape variety, known for it's long growing season and late ripening. It is susceptible to fungal diseases... So, in that light, appropriate for this project. That is to say, this is likely to take a rather long time to ripen, and may find itself dead and useless somewhere along the way.

Also, there is a music reference: In Mozart's opera Don Giovanni, the titular character Don Giovanni calls out for a glass of Marzemino just before his deliverance into hell. Which is perhaps where I will be sent if I finish this...

It will be (almost) full range dipole (lower end being where it is unlikely to remain dipole). The goal is minimal driver count, minimal crossover, and ~90dB sensitivity.

It will start with some fiddling and experimentation. On my doorstep tomorrow should be some Neo8 and Neo3 planars to start the fun. I will be playing with some waveguide-ish setups here to see what can be done to improve power handling and low end response.

That's all for now. But once I found the right grape, I had to start the thread.

:Z

Sounds like good clean fun! Can't wait to see how this develops, even if I haven't been playing with dipoles for a while- doesn't mean I might not come back there! Let's see what you think of the Neo's....

[---k---]

Man, you're going to be one busy boy. How many projects are you going to have under way here shortly? 3-4? Sounds like a good reason to get that laptop measurement system up and running.

Looking forward to hearing these.

[dlneubec]

Let me guess, some kind of vertically oriented waveguide using tubes or partial tubes to form the "waveguide", kind of like RAAL is doing with his omni tweeter, only front and back for a dipole waveguide?

Since I first did a conventional design with the Neo3pdr, I've wanted to play with a waveguide solution for that driver, but haven't got to it yet. Whatever it is, it sounds like fun. I heard an design with those two drivers by Scott Sehlin at the Iowa DIY this year and they had a really nice sounding midrange, very clean and open sounding. It was all monopole, I believe and no waveguides. He had them in a narrow tower with two RS125's or RS150's for he bass. The bass was the weakest point in that system, at least in that large Iowa hall. I bet they sound great in a room with a some walls nearby.

That's the cool thing about speaker design, that is, if you have an open mind. There are so many avenues to explore that can give you great sound, that it's not hard to find a fresh new challenge.

[cjd]

No tubes, exactly. No. Though in other ways, that could be the general idea as well... suppose it depends how you look at it, and maybe you'd say yes, that's what I have in mind.

If I mention that right now I have my eyes on crossing the Neo8 to a 15" driver would that perhaps give you some ideas? Of course, I do not yet know if that's going to be possible, so first things first. Could easily cross to an 8" as well but that would end up a 5-way (or 6-way, if I count the fact that if I get the ultimate room for these there'll be an external sub, hopefully IB... unless I can get 16Hz dipole adequately...)

First though I want to focus on WG shape and see if I can discover any tricks - I'm sure that I will be wandering along paths others have walked, and I don't care. I learn best that way, but more important, I have a ton of fun. I do, however, have some things I want to try that I have not seen done. Maybe I'll discover why. . .

And given how projects go around here (not to mention my housing space, room in which to put finished speakers) these could be years in the making, if they get done. Which is why I suggested the grape varietal was perhaps all too appropriate in its traits.

I should have the remaining stuff to get the laptop doing measurements showing up in the same box as the Neo's.

If I don't have at least 15 or 20 projects going at once, something is wrong with me. You should worry if I FINISH a project of my own. . .

[Johnloudb]

Okay, I see the problem I'm having. I get started on a project, hit a bump in the road and start another project. I have like six projects going and go back an forth between them, and invariably start another project along the road.

CJD, Very interesting project! I like the project name, and appropriate like you say. But, at the same time .... DON'T let the grape win!!! Seize the grape! ... Carpe diem the grape!

[dlneubec]

I hear you guys. I'm pretty good at staying focused on completing one project before I start the next, but always have a several concepts bouncing around in my brain, or in the preliminary cad design stage.

The RAAL omni discussion has me thinking about an inexpensize omni design inspired by the RAAL design that might be pretty easy to build. PE happens to have some buyout drivers available right now at under $8 each, which has me thinking even harder about that concept while they are still available. If it can be done with a dome tweeter rather than a ribbon, it could be a really inexpensive speaker, but that is rather hard to predict without mocking something up and measuring it.

[Paul W]

First though I want to focus on WG shape and see if I can discover any tricks - I'm sure that I will be wandering along paths others have walked, and I don't care. I learn best that way, but more important, I have a ton of fun. I do, however, have some things I want to try that I have not seen done. Maybe I'll discover why. . .

Hornresp and AxiDriver are two good packages for evaluating different shapes. Hornresp is limited to "the usual suspects" tractrix, exponential, spherical, OS, etc. AxiDriver lets you "roll your own" flare (forces it actually). HR is fairly intuitive, AD is more difficult (at least for me).

[cjd]

They don't evaluate a great many of the things i want to try, but they should definitely help me arrive at a basic starting shape. I've read some about both.

Would the blue/pink insulating foam have bad side effects being used for shaping raw shapes quickly for test purposes (that anyone knows of, or imagines, or...) ?

[Paul W]

Haven't tried it, but think it would be fine for prototyping. If you open up the pores in the foam, maybe a tiny bit of influence on the top end, but nothing to influence a decision.

[villastrangiato]

No tubes, exactly. No. Though in other ways, that could be the general idea as well... suppose it depends how you look at it, and maybe you'd say yes, that's what I have in mind.

If I mention that right now I have my eyes on crossing the Neo8 to a 15" driver would that perhaps give you some ideas? Of course, I do not yet know if that's going to be possible, so first things first. Could easily cross to an 8" as well but that would end up a 5-way (or 6-way, if I count the fact that if I get the ultimate room for these there'll be an external sub, hopefully IB... unless I can get 16Hz dipole adequately...)

First though I want to focus on WG shape and see if I can discover any tricks - I'm sure that I will be wandering along paths others have walked, and I don't care. I learn best that way, but more important, I have a ton of fun. I do, however, have some things I want to try that I have not seen done. Maybe I'll discover why. . .

I've been modelling a design using the Neo8 for about 16 months now - an unusual line array configuration crossed to a low mass 8 inch woofer TL aligned array. The bulk of the design effort thus far has involved creating the highest performing TL layout for 6 drivers with 90 liters of enclosure displacement each. It's become a real struggle to balance baffle width, weight, and enclosure depth - to produce a result that is "livable" for the average living room.

Getting to your suggestion of crossing the Neo8 to a 15 inch driver - I'd caution against it. With moving mass being so vastly different, you're going to have a hell of a time getting a smooth power response match. Cross too low and the Neo is going to strain noticeably. Cross too high and the woofer's high inductance and mass are going to contrast sharply with the Neo8's ultra clean spectral delay characteristics. If you have your heart set on a big driver cross to the Neo - and I can understand why you'd want to go that route initially (minimum number of crossover points) - there are a couple of reasonably priced aluminum woofers and subs that are remarkably clean in the 500hz region - despite mass ranging from 40 to 280 grams - can you guess which one's I'm thinking of? :B
It's interesting - if you were to build a BG system with an aluminum woofer - you'd essentially have an all "aluminum" system as the Neo's diaphragm is essentially a thin aluminum etching on a virtually massless substrate.

[cjd]

I've been peeking at the AE drivers... As well as B&E and others. The mass difference is understood, though I would not be trying to cross to a woofer (definitely not a subwoofer), but more a large mid with some low end extension, excursion to handle it, and surface area to move air without a ton of excursion. And crossing to a 15 would first depend on managing the strain issues properly, which may or may not work.

More/other drivers would be used to fill in below.

But, I'm still open to using a smaller driver in the mix as well. I won't know till I get done fiddling with the Neo's, and that will be after some of the projects I have stacked up for others get done.

I am still not understanding how HornResp works fully, so not even past modeling.

C

[villastrangiato]

If I were shooting for a vented alignment, I'd consider the Usher 8836a for it's truncated frame, low mass, excellent distortion characteristics, and great low end performance. With the truncated frame, you get the added benefit of pushing it closer to a pair of Neo8's in a WMTMW configuration which allows for a higher crossover point. The 7 inch diameter also gives you added flexibility in terms of matching beam width at higher frequencies than the average 8inch. And based on available measurements, the 8836 is no slouch in providing clean lows. With two of these in a decent size enclosure, you might not want or need a separate sub. But with a 300 to 500 watt plate amp and a decent 12 or 15 inch driver - it wouldn't take much to improve the very low end while bumping up the entire system's total SPL capacity. But for most folks, I'm guessing 250 wpc might be enough....you may or may not be like "most folks" :B

[cjd]

Uhh... Did I fail to mention this is dipole?

[villastrangiato]

You said something about "almost" full range dipole......not sure if you were planning on "open baffling" midbass or bass units. I suppose the 8836a could work OB - it's not as wide open as some but it's not an RS180 either. I searched this site for 8836a builds and couldn't find one - which is surprising because the measurements ZAPH has for it place it in the same league as the SS 8531 at less than half the cost.

Whatever you come up with, it's going to have to take into account the planar driver's limited vertical dispersion. So if you are expecting flexibility, it might be desirable for your OB design to accommodate a pivoting monitor layout to adjust between sitting and standing position. If you go with a WMTMW configuration, the separation between the two planar midranges may work in bridging between a 6 foot and 38 inch listening height - polar response should be interesting as I haven't seen any MTM builds on here yet with planar midranges.

[cjd]

Um... full range starts at 16 Hz... I figure 30 is the lower reasonable limit, expecting 40 for dipole.

also greater than 90dB... I.hope. this has been a long time just in conceptual pondering.

[villastrangiato]

The name: It's an Italian grape variety, known for it's long growing season and late ripening. It is susceptible to fungal diseases... So, in that light, appropriate for this project. That is to say, this is likely to take a rather long time to ripen, and may find itself dead and useless somewhere along the way.

Also, there is a music reference: In Mozart's opera Don Giovanni, the titular character Don Giovanni calls out for a glass of Marzemino just before his deliverance into hell. Which is perhaps where I will be sent if I finish this...

It will be (almost) full range dipole (lower end being where it is unlikely to remain dipole). The goal is minimal driver count, minimal crossover, and ~90dB sensitivity.


:Z

K....I wasn't exactly sure what you meant by lower end. Either way, if you can incorporate the 8836a into your design, you'll definitely be a trend setter - although I'm still not sure why - the thing should be a lot more popular than it appears. Regardless, I'm predicting like Javier Fijuerta, you are going to have fun with vertical dispersion issues and planar drivers in a point source design - so you might want to start pondering that minor inconvenience. It may actually trump all the other little annoyances that spring up.....

[cjd]

Ok, so. For those that haven't been around as long:

Music in my collection includes a lot of classical and no small bit of organ, which has a fundamental of 16Hz - 8Hz is a better target but I'll take that as my F3. No way am I going to try for the last octave or three in pure dipole, as much fun as that would be. Full range is to 16Hz for me.

As for the Usher: it fails to meet my requirements for this design in just about every aspect. I'm sure it's a nice enough driver but would take too many to reach the sensitivity target (well, might only need two since I'd need to install it between the Neo8 and a mid-woofer, which would need a woofer after, and then a sub (monopole) ...

If I had some on hand to use, they'd almost surely not go into this design. For the price, there are other options that are more attractive (both visually and sound-wise). It's a fine driver but...

This is not the first foray into dipole I've taken, though it will be the first with anything more than a snapshot or two posted for gits and shiggles.

If I need to step in with a driver to fill through ~1k+ for the Neo8 it will probably (but not guaranteed) be an 8" and that would slightly alter what drivers I consider to fill out the bottom end.

[villastrangiato]

As for the Usher: it fails to meet my requirements for this design in just about every aspect. I'm sure it's a nice enough driver but would take too many to reach the sensitivity target (well, might only need two since I'd need to install it between the Neo8 and a mid-woofer, which would need a woofer after, and then a sub (monopole) ...

If I had some on hand to use, they'd almost surely not go into this design. For the price, there are other options that are more attractive (both visually and sound-wise). It's a fine driver but...

This is not the first foray into dipole I've taken, though it will be the first with anything more than a snapshot or two posted for gits and shiggles.

If I need to step in with a driver to fill through ~1k+ for the Neo8 it will probably (but not guaranteed) be an 8" and that would slightly alter what drivers I consider to fill out the bottom end.

Well, that's an intriguing assessment. If you do have a good low distortion (-60db 3rd harmonic from 80 to 1000hz at -10db reference) with a 30hz fs, low mass (under 30gm) and low inductance (less than .6mh) driver in mind that costs less than $100 and has a nominal 2.83V sensitivity of 90+db - and it's magnetic structure is well suited to OB configuration - let me know.......I'd love to use said driver in my next design. :B

I've been looking for said mystery driver now for the past 5 years. The closest I've seen to something like that is 2 to 3 times the budget level.

[cjd]

Those are not my requirements... If they were, I would probably find the Usher very interesting indeed. A 7" driver with only 5mm xmax and only ~90dB sensitivity might work for me with two of them as a lower midrange driver, though there might be some C2C issues introduced as a result.

The AE TD10M isn't a 7" to be sure, nor is it $100 (though it's not far from the cost of the 2 Ushers I'd need), but it's one of the 10" drivers I'm looking at should I need to bridge the gap and cross to the Neo8 higher.

I never said it was a bad driver or that it did not meet your needs, just that it does not meet my needs. I've looked at it in the past (I gave it a consideration for my HT setup, in fact, and ended up using the RS180-4... a better blend of features and price for my requirements)

C

[villastrangiato]

Those are not my requirements... If they were, I would probably find the Usher very interesting indeed. A 7" driver with only 5mm xmax and only ~90dB sensitivity might work for me with two of them as a lower midrange driver, though there might be some C2C issues introduced as a result.

The AE TD10M isn't a 7" to be sure, nor is it $100 (though it's not far from the cost of the 2 Ushers I'd need), but it's one of the 10" drivers I'm looking at should I need to bridge the gap and cross to the Neo8 higher.

I never said it was a bad driver or that it did not meet your needs, just that it does not meet my needs. I've looked at it in the past (I gave it a consideration for my HT setup, in fact, and ended up using the RS180-4... a better blend of features and price for my requirements)

C

Agreed about the Xmax - the one week spot on the Usher compared to the SS it's supposed to compete with - I think the SS lists 6.5mm but I'm not necessarily glued to those numbers - one manufacturer's idea of "linear" is like another's "let it all hang out" point..... 8O

The Acoustic Elegance stuff does look nice - I was a little disappointed though in the availability of specs/measurements. I'm sure that will be cleared up soon enough. I checked the TD10 out today on the site and the link to the T/S parameters was broken......

The only other driver that comes to mind as a natural for this app would be the 18Sound 6ND430 - very low distortion, and good extended off axis response (despite a fairly high .99mh inductance), very high output capability (130 w) and efficiency (tested @ 91.5db), low mass (9.3 gr). The limited Xmax and response drop off at 100-200hz is not very inspiring but if you're already going to cross to a big beasty sub or AE driver anyway for the bottom end - low end performance doesn't seem necessary. The only other thing I'm not sure of is the openness of the frame. Since this driver automatically means four way - you're almost at the point of - why bother with the planars? - they'd probably become more of a nuisance if the 18Sound can cover their territory with equal finesse. This is why my immediate inclination when crossing a Neo 8 is to go with a stout pair of 7 or 8 inch premium drivers that have enough low end grunt to seamlessly integrate with a decent (possibly monster?) sub. If you're resigned to go with a four way and all it's added crossover adventures, you might as well have a mid bass unit that allows the sub to be a sub.

[cjd]

That's why I'm looking at larger "mids" you see. The 12" and even the 15" M series AE drivers certainly are clean notably high and can then cross to more beastly drivers for bass duty - it all comes down to how low I can use the planars. If they don't pan out I am looking at a 6.5" or 8" midrange (the 18sound is on the list, though they all have magnet size issues, which is why I want to use the planars...)

As I've said, this has been a long time in the "choice pondering" stages, and I've finally gotten to the point where some ideas I want to try out may (or may not) get the Neo8 usable over the range I want, and I have decided it's time to start with that. Even if that fails I may still have some tricks worth sharing out of the trials.

I could just build an Isis or something were I so inclined...

[satie]

I am running a triamped Tympani IV with a 6 X Neo8 midrange array. Recently, I moved to running the midrange without crossover, essentially letting run to the array's natural acoustic rolloffs. The range is from 150 hz to 11 khz, where I add in the Bass panels and 6 ft Maggie tweeter to fill out.

Prior to this, I was running the Neo8 midrange array at LR4 on a Marchand 44 crossed at 300 and 5k hz.

I have not heard anything more beautiful than what I get from this setup, whether running it with my modded Dynaco III in triode, or my modded Nuforce 8.5 (for larger scale music) . Losing the Marchand on the midrange is a phenomenal improvement. Not “veils lifted”, not “clearer”, not “jaw dropping”, but a totally different animal with rich tonal textures and hall reverberation, endless detail.

I am still wary of running the Neo8's with low frequency input, and was wondering if It would be better if I rewired them into all parallel (0.62 ohms) rather than 3 X parallel pairs (5.1 ohms) to lower the current going through each driver so as to avoid thermal issues - the 20 W RMS power limit - vs. 150 W peak. But I don't think it is a problem since the Dynacos come close to providing enough power, compressing only in the loudest of musical passages with 30 W/ch. They do well on peaks but not on sustained loud passages. So I am thinking that with the Nuforce amps I am using no more than 20 W RMS and 40-50 w "music power" and 200 W peak. I know that I use that much power and to show it I have a driver with the coating blown off from playing with them one per channel during my initial evaluation.

Perhaps Chasw98 will help us by running a dynamic FR sweep on his Neo8 PDR array to see how the array's FR behaves at higher output SPL - to 100 and 110 db SPL at 2 or 3 meters. I was wondering where they bottom out as power is increased.
Anyway, my experience running the Neo8 without a crossover brings me to suggest you figure out whether you can do it too in your project.

[cjd]

Uh oh. Still breathing. Just gave a pretty big kick.

I just might hit dipole to 16hz with a probable 98dB max at 3m each... so that might be enough. Or partial dipole to 24-30hz and monopole to 10hz... depends on max spl I care about. Decisions decisions.

I've switched to the Neo10 from the Neo8. One or two, not sure yet. Need a 15in to cover 70hz-300 or so? So still so many choices.

[gbegland]

Uh oh. Still breathing. Just gave a pretty big kick.

I just might hit dipole to 16hz with a probable 98dB max at 3m each... so that might be enough. Or partial dipole to 24-30hz and monopole to 10hz... depends on max spl I care about. Decisions decisions.

I've switched to the Neo10 from the Neo8. One or two, not sure yet. Need a 15in to cover 70hz-300 or so? So still so many choices.

Hmmmm, one or two neo10 and a 15" up to 300hz. Sounds familiar....

:T

Greg

[cjd]

Hmmmm, one or two neo10 and a 15" up to 300hz. Sounds familiar....

:T

Greg

Yup. Still playing with waveguides on the neos. If that works it'll probably just need one but may still get two. If I give up on that two it is.

I have always done this where I know the obvious direct easy answer that works perfectly but I have to get there the long way. I learn more and definitely have more fun.

[cjd]

Bwaaaaahahahaaooooof! Heavy. One of four of the bottom end now in hand, with the other three being picked up next week. Fun times.

[cjd]

Filled in the ~60Hz-300Hz range I think! Now to see if I can get the Neo10 happy that low at a reasonable level without resorting to using a pair. Having some luck on that end perhaps, looking to put together a more solid prototype soon - these prototypes are light enough I can work on them - the Nebbiolo is off limits due to the back, and the OTHER two projects I now have all the parts for (no name yet) will sit in the "still tinkering with the probable enclosure design" for a while.

I really want to get that pair of dual Maelstrom 18 dipole subwoofers built though... :B No clue where I'll put them... I believe they'll be good up to ~110dB at 16Hz dipole...