[richidoo]

I'm thinking same as you, want it all in an OB design. These look interesting:
http://www.6moons.com/industryfeatures/feastrex/feastrex.html
Some reviews out on google = "feastrex". Not cheap!

Rich

[JoshK]

I have a pair of Fertin 20EX on the JELabs OB, and they definitely will not 'rock out' with you and your entire neighborhood. I would think biamping, with a 200hz PLLXO for the amp driving the Fertins + a supertweeter (I use a Fostex FT96H) and a big SS amp driving a bunch of 15"s would be awfully nice.

If you search for Fertin in this forum, the fullrange forum over at diyAudio, and High-Eff at AudioAsylum you'll find many comments on the Fertins by myself and others (nl - Nate Lewis at AA has been doing a bit as of late as far as highpassing his Fertins).

If you are set on coaxs, I would recommend the Radian 15" + a bunch of Hawthorne 15" Augies for bass support.

Regards,
John

Nate's are the ones I heard.  He invited me and some other guys over to his place last weekend.  Very nice guy.

[nullspace]

Hi Josh --

I'm sure that must have been a good time. Nate posted an invite over on AA, but Phila. -> CT is too long of a drive for me when I have too much work around the house to get done. As much as anything else, I would've loved to hear his amplifier setup.

Regards,
John

[Scott F.]

While I haven't heard the Fostex 200a's, I have listened to a number of the other drivers mentioned.

Of those, the Supravox field coils are extremely nice but they do have a minor drawback. Thet start to roll off at about 8k or so. The ones I heard were in back loaded horns. They packed quite a punch in the bass region. I have no idea how they sound in an OB arrangement.

I currently run Lowther PM2A's from 150hz and up. They are clean, extended to about 14k and do the best job I have personally heard in an open baffle. The PM6A runs a really close second. One of these days I hope to play with the Festrex.

Bass in an OB is best left to big drivers. Like any speaaker design, don't try to force a driver to do something it can't (or shouldn't). An OB arrangement 150hz and up wth a sealed/ported bass driver gives you the best of both worlds, especially if you use an active crossover.

..just my $.02

[jimluu]

My four subs are here

Thinking about these radians:

http://www.usspeaker.com/radian%205312-1.htm

[D OB G]

Hi jimluu,

Maybe the various options you have could be collated, and forum members could elaborate their experiences in each category.

You have four subs, your options appear to be:

1. Full-range augmentation

e.g Fostex F200A (well regarded in Japan)
     Visaton B 200
     Supravox
     Fertin
     e.t.c
     others might like to add to the list, and give their pros and cons, especially if they can give their  experiences of  comparisons of drivers they have heard and know.


2. Wide-range + tweeter

    e.g any of the full rangers plus tweeter.

    Tweeters including:
    cone
    dome
    ribbon
    horns (compression drivers)

3. Dedicated midrange plus tweeter

Pros and cons:

1. point source, continuous transition across the frequency bandwidth, especially if not twincone        (contentious), and if with phase plug.  Please add other pros.

   beaming, peaky upper range (may need compensating circuits), intermodulation distortion, difficulty handling complex signals e.g. orchestral music.  May have limited dynamic range (except for things like appropriately loaded Lowthers, which may or may not include open-baffle loading).

2. What tweeter?
   
    Very few dedicated cone tweeters these days.

    Domes

    Not especialy like on this forum it seems, but have dispersion advantages.
    Rise times can be very good.  If crossed over at 2-2.5 kHz, can take advantage of avoiding commencement of   reducing off axis response of full-ranger to dovetail nicely with continuing flat off-axis response, which might only fall off at 8 or 10 k Hz or so. i.e. good dispersion, which is rated more highly by some than others.  Acts as a piston to a higher frequency than full-rangers i.e. flatter frequency response.
     
     Not open baffle, although some have sophisiticated rear chamber loading.
     Some consider there to be a tone difference when crossing over, minimised with 6 dB per octave slope.

    Ribbons.
   
    Very good rise time. Detailed.

    Fragile (relatively).  Off axis response generally not too good.

    Horn loaded compression drivers.

    Efficient- may be only match for efficient full-rangers. Can go very high in frequency.

    Horn distortion

3. Midrange

    Multitude available.
    Pros and cons of each cone material. Some have a good enough bandwidth to almost act as wide-    rangers.  Others have terrible out of band characterisitics (e.g magnesium cones e.t.c)



I know this is long winded, but it seems to me that a decision needs to be made between 1, 2, and 3 rather than this driver or that, unless you get a chance to hear all the the contenders for yourself.

I hope though that this will invite contributors (I hope I haven't done an injustice to anyone- please correct me if I have e.g. Lowthers on open-baffles) to impart their experience of the whole 1,2,3 differentiation, but also of individual drivers within each classification, and especially of their experiences of comparisons between drivers they have heard and know.

David



   

[jimluu]

I think that coaxials also deserve their own catagory as well. 

[RAW]

Ribbons.
    
    Very good rise time. Detailed.

    Fragile (relatively).  Off axis response generally not too good.

Care to explain this one for me?

Domes

    Not especialy like on this forum it seems, but have dispersion advantages

What ribbon are you revering to?
People who make a braze comment with no facts to base a comment on should be made to do a little explaining.

That is like saying all domes have the worst dispersion....
Yes some do others do not.So do not make a point fact directed to a single driver witch is not a fact.

Yes if you use a ribbon against a dome the horizontail disperson will go with a ribbon ( less you talk the G1 due to element width)

Vertically this will change from ribbon to ribbon no if ands or buts this applies the same with dome tweeters as well.If you want to compare and say all ribbons have poor dispersion please provide some details of the facts for your statement for ALL ribbons.
Tell you what I have measured all Aurum Cantus ribbons and the LCY and a few others.Over 16 in total different models and have all the off axis response from 0-60 off axis vertically and horizontally

Below is some test done by Mark K not myself showing the Usher 9950 and a G2Si .
This shows the waterfall distortion of the Usher is very high compaired to the G2Si  !
Then add in the off axis response.As you can see the ribbon ( G2Si ) well kind of walks all over the dome on axis, let alone off axis.

Next people make a general statement of ribbons to bright.
Yes and no.
AS the ribbon will not be really bright but the crossover design has the final out put for that ribbon.Anyone can sure make a comment about a dome being bright and ear ringing as well.All in thew crossover not really the dome model

[D OB G]

Hi jimluu,

Yes, I shouldn't have left out coaxials.

Thanks RAW,

As I said, I hope I haven't done an injustice to anyone, so thank you for correcting me.

I was seeking to systematize "the quest" and made generalisations as a framework.

As I invited people to give their pros and cons, and share their experiences of comparisons of drivers they have heard and know, your description of ribbon tweeters certainly expands the contribution.

I did say generally (with vertical dispersion particularly in mind), not ALL, so the graphs you provided have certainly given us some objective data, which obviously shows some good results for the G2Si, provided that the 15 kHz to resonance region doesn't give any troubles, and also possibly explains the detail that is often associated with ribbons.

I believe this is the sort of side by side experience that will help in trying to answer the original question of this thread.

By the way, which ribbon did you settle on, and why that particular model?

Thanks again RAW.

David

[D OB G]

I've just found a very interesting site by John "Zaph" Krutke:

http://www.zaphaudio.com

Two components to his site.

Objective measurements, where he places low distortion as the single most important factor in loudspeaker design (something I believe Linkwitz is concerned about ?).
He addresses a number of tweeters in categories such as:
-Battle of the Non-Domes
-Tweeter Mishmash
-Tweeter Off Axis response (look at that Vifa XT19 3/4" ring radiator!!)

Commentary and "rants", where (relevant for us open-bafflers) he contends that:
-Woofers with lower X-max sound better

Generally a controversial and thought provoking site.

David

[JLM]

Hey Rich,

Isn't this thread entitled, "No expense spared open baffle"?  Yes the Feastrex is an expensive driver, but so are the field coils.  IME if you deny the advantages of going active, you've missed the point of this thread too.  And if you try to do both, the best compromise with cost/space may be the Orions which weigh in at over $6000 (with amps). 

The Feastrex/Augie would stay south of $2k plus amps.  The F200A less than half that.

Note that these 3 options have been built, used, or reviewed.  Tomek (an occasional member here) has used the F200A in O.B.

[el`Ol]

I remember a guy who bought an F200A and an AER MD2B, of course an unfair comparison keeping the price difference in mind, but after the comparison he considered to let the Fostex do the bass job for the AER instead of selling it off. The strength of the F200A is probably rather in single-driver solutions, not as a mid-high driver.
An other thing: Why do you never hear about the Supravox 165-2000? It would fill the gap between the 215 sig bic. and the 215 EXC.
http://www.supravox.fr/haut_parleurs/165_2000.htm

[nullspace]

An other thing: Why do you never hear about the Supravox 165-2000? It would fill the gap between the 215 sig bic. and the 215 EXC.
http://www.supravox.fr/haut_parleurs/165_2000.htm

Because the Supravox dealer here in the US doesn't care for them. A couple of years ago I spoke with one of the two guys running the show, I think it was David, and he recommended either settling for the 215 Sig Bic or saving up for the 215 EXC. Myself, I'd really like to hear the 215 EXC at some point, just to see how it compares to the Fertins.

Regards,
John

[jimluu]

Who makes supravox?  I've listed to fostex, and temped to get a pair of audio nirvana, hemp acoustics full ranges for comparison.  Supravox is way too expensive for that sort of experiment, but I am interested in how they sound.  I'll have to look for some at the RMAF.

[el`Ol]

Also french, and a bit cheaper:
http://cgi.ebay.de/Cabasse-Breitbaender-open-baffle-Schallwand-300B-2A3_W0QQitemZ120150516414QQihZ002QQcategoryZ22062QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[lankester]

Hi,

Just our web site up and running:                http://hstrial-alankester.homestead.com/index.html

Supravox drivers are expensive but very sweet sounding.  We love the 215 field coils.  If you are talking about no expense spared that is.

We are still prototyping the Capilano drivers. 

[raov1]

  I've hear the Supravox FCs and presently own a pair of the Fertin 20EX. I've set it up in the Fertin baffle ... which is excellent. I also heard the AlNiCo PHYs (which would make a good competitor).
There are a few differences in the Supravoxes and Fertins as I rememeber. The Supravoxes need a super tweeter while the Fertins easlily reach 20K Hz. Lower end has the same problem as most single drivers, however good enough. There is a North American representative in Canada for the Fertins, while there is a US distributer for the Supravoxes.
  As previously mentioned ..... vocals and small music is absolutely phenomenal on the Fertins.
  If you want to go all out  ..... consider a pair of custom order Feastrex feild coils which are well over 20 grand for the drivers alone !!!!  aa
 (does not necessarily mean better)
  Apparently Fertin is in the process of patenting an expensive "radical new driver".
  If not field coils, consider AlNiCo drivers ...

  I don't know much about this, however it has been used as ob
  http://www.fullrange-speakers.com/eng/tech/mdxtech-e.htm

[Rudolf]

I don't know much about this, however it has been used as ob
  http://www.fullrange-speakers.com/eng/tech/mdxtech-e.htm

Those are the fake-AER drivers a former employee of AER is building. If you want ther real ones:http://www.aer-loudspeaker.com/

[aerius]

Well, whenever Lynn Olson & company get around to finishing it, I suspect the successor to the Ariel will likely be very close to the state of the art in terms of open baffle speaker design.

[Rudolf]

Well, whenever Lynn Olson & company get around to finishing it, I suspect the successor to the Ariel will likely be very close to the state of the art in terms of open baffle speaker design.

When looking at this forum, I don´t see any common denominator what the SOTA of OB should be. 
Looks like OB builders are more into art statements than state of the art. 

Regarding Lynn Olson: His present design considerations are seriously stressing dipole behaviour IMHO. While OBs don´t necessarily need to be dipoles, I wonder where he is heading to.

Rudolf