Can you provide a description of the tweeter or crossover?  Is this an Eminence driver?  What is the crossover frequency?

I started another thread about these somewhere around here.

I've got to get over to his place (only a 2 hour drive).

Hi JohninCR,

It is no secret that I am quite ga ga over OB's myself...the best kept secret in
audio...a paradigm shift in sound reproduction...

Perhaps the Hawthorn driver is what I need to experiment with next...I like
the 15 inch size...and the bass response you are reporting (getting) sounds
revelatory...

However I am not quite certain what you mean when you say...

"...I'm getting nice solid bass into the 30's and that's with the Joint Chiefs on
another cab 27" off the floor!..."

Having a bit of trouble visualizing that...although I assume you purchased
the Hawthorne OB "stock" cabinet...

Thanks for sharing your experiences with us...very intriguing indeed!!!!!

The world of audio will never be the same once seasoned audio enthusiasts
understand what an OB sounds like...it seems impossible to believe that
something that simple can create a revolution in sound reproduction...

However we know better!!!!

Thanks again...please keep us informed...

Warm Regards -Richard-

Richard,

No not the stock cabs.  You'll never see me with a flat or flattish OB.  IMO it's just a waste....no real bass.  I used my own design which is a modified U-Baffle with 5 sides instead of 4 like JohnK's NaO.  I thought no parallel sides was better and I was right.  I also modified the shape of the back and that paid big dividends too, in the form of eliminating cavity resonance.  

From the front you see a 15" driver that barely fits on it's pentagon baffle.  The maximum depth at the back is only 16".  I haven't decided what kind of stand to make, so they are just temporarily laying on some 12" wide by 27" tall cabs that are not in use.  I caculated an Fequal of 72hz, which equates to a flat baffle over 5ft wide and 6ft tall for the 36" tweeter height I have them at.  I shrank that to about 16"x16"x16", cool huh?

I haven't been able to find my SPL meter due to a recent move, but a tone sweep is telling me the -3db is below 40hz.  No boundary reinforcement, they're 10ft from the back wall, and no EQ.

I think I understood Darrel in saying that the 95.8db efficiency is as a system, not before the XO.  I believe it because I know my little 2 watt Decware Select SET was pushing that 8 ohm load up close to 100db when I was listening today.

Regarding the XO, I've been able to hear every one I've put between amp and speakers in the pass other than a single inductor on bass augmenter woofer.  Even a simple cap I tried on my FE206 based OB's to protect my 206's from LF content had to go because it degraded the sound.  I'm a real minimalist.  With the Iris though I've found nothing problematic at any frequency.

I like the mids even better than with my 206's and that says a lot.  Plus I'm getting about the same level of detail because I'm still hearing those subtleties that my 206's showed me which no previous speaker has.  The top end blows my 206's away.  That's about as close as you'll ever get to a poetic audio description out of me, except that I was already able to get them to pull the disappearing act and that's a difficult task with any OB.

I was really caught off guard because Darrel had down played how good the drivers were and I was just expecting a pro driver with a high Q and low Fs.  I own some Eminence coax with their old compression tweeter that had a sibilance problem and lacked real detail and this modded new one is in a different league.  Loud or mellow these thing sound great.  I did put them on my mid-fi Denon HT receiver to apply some power, but I don't have the baffles securely attached yet and they definitely need a good heavy base to keep that 15"er solid.  When I applied some significant power things got loose, but I'm confident that it wasn't the driver, because when I held one of the baffles in place the driver was still just idling along despite the very high SPLs.  With heavy bass content you probably can't push them much above 100db without getting to max excursion.  Even if you did push them too hard, you aren't going to hurt them due to their pro driver heritage and much larger mechanical limit.

I was on the verge of buying some B200's, but I knew I'd still need bass assistance and I really wanted to see how far I could take this whole single driver thing.  When I found out Darrel's were only about month away, I decided to just make them a late Christmas present for myself.

For about a year I've looked at literally thousands of driver specs, trying to find just the right one and I believe I've found it in the Iris.  All I need is another 5 for my HT setup, plus 2 of the Hawthorne 15" bass augmenters when they come out to use in a U-Baffle sub, then my hobby can go back to just music listening and forget the chase.

The only thing I believe could be a possible improvement, and it's still just a maybe for me, would be to go active and biamp the unit and bring the woofer and tweet into exact time alignment (which is very close already with the tweeter mounted in the woofer's magnet assembly).  I'm not sure how audible that difference would be, but I understand going active is a step up.  Plus I have 2 Decware Selects, so why not biamp and get some extra head room?

JohnCR,

Much to like here, wish we could get some graphical information on your O.B. mounting (can't call it a cabinet now can we?).

With the tweeter mounted as described it picks up waveguide reinforcement as SPTech describes to help lower the crossover point (highly necessary I would think crossing over to a 15 inch driver).

The image of the crossover looks quite impressive.

Professional use build quality and power handling capacity.

Of course the very reasonable pricing.

But this really ...

I'll give my baffle plan to anyone who buys a pair from Darrel's first run.  I don't want to make it public yet as I'm seriously considering making it a kit.  It works that well.

OK, not single driver, but it is a single woofer OB.  I'm a minimalist too.  I mention active XO, because guys using it, swear by it.

I don't know what you mean by bass reinforcement because these probably go at least as deep as your unfiltered MLTL's .  They honestly don't need augmentation.  2 Iris's + 2 Joint Chiefs + 2 watts is really all you need.  Trance or pipe organ music are the only exceptions I can think of.  Sure I'd like flat to 30hz.  Find me a high Q driver that has an Fs of 30hz and sounds as good as Darrel's and I can build a flat to 30hz baffle in a reasonable size.  That driver doesn't exist and the Iris is the only thing that comes remotely close.  Believe me, I've been looking.  

In talking to Darrel about his work with the designing engineer at Eminence, toward the OB bass augmenter he wants to put out, it seems that 30hz isn't possible.  The only driver that's been able to get that kind of extension on it's own in OB is the Dayton IB15 (also made by Eminence), but it's essentially a high Q subwoofer, which means a heavy cone, much higher Le, etc.  Those simply won't play high enough.  You could probably use that along with a B200, but you still need an XO in the 80-100hz range and that IB15 may not blend well enough with the B200, even at that low of an XO point.  You'd also have to biamp because of the sensitivity gap, so you're back to a complex system again and there's still a question mark about integration.  Also I question any fullranger's top end, but it's what a tweeter is specifically designed to handle.  My FE206's are ragged at the top and my FE127's are attenuated at the top.

To me it's a no-brainer for only $300 for anyone who wants to try the OB sound everyone has been raving about.

BTW, I've gotten mine to pull the disappearing act and when I finally tune my room I think the imaging will become more focused.  If not, it's no big deal because I'll take the open natural OB sound over a holographic image.  That surreal imaging is a hit or miss thing with recordings, but the OB sound isn't.

Hi JohninCR,

I sent my post before I read your last post...so I did not realize that you may
have plans on creating a kit based on your OB design using Darrel's speakers...

I mention this so you do not think I am trying to "tease" out information
from you that you have clearly explained is not available publicly...
of course I honor your position...

Any of us who are looking to bring their OB experiments
to the highest level possible owe you a great deal of gratitude for bringing
Darrel's drivers to our attention...and for sharing any information you can
to help light the fires under our own investigations...

Thanks again, John for your generous sharing of ideas with us...

Warm Regards -Richard-

In this world there is no perfect speaker, they all have to make compromises.  But this driver would seem to bring O.B. to the very front of the class.  No pry, no slam intended.

In this world there is no perfect speaker, they all have to make compromises.  But this driver would seem to bring O.B. to the very front of the class.  No pry, no slam intended.

JLM,

I agree, however, this is the first time I've gotten to a point where I can't put anything in the "dislike" or "I want more of X" column.  I would like the Iris in a 10" or 12" model for use as HT surrounds, but those will be coming.   At some point I'll have to get a pair of B200's or one of the Supravox models to know for sure.  Plus I'm sure I'll have to try the active XO route, to see how audible that difference is.

I'm a firm believer that the speaker is the most important part entire chain.  That search has been almost a daily thing for me for going on 3 years.  Now I can finally tune my room and finish my subs.  I may spend a little time and money on the electronics, but I'm really waiting for the computer solutions to fully develop.

Time to spend more time building and listening to the music collection.

johnincr   thanks for your work and faith in the new driver

may i have plans for your speaker; i just ordered the iris drivers after two inquiries with darrel.  he was very patient with me.  i have ciare ch25 0 right now but they really roll off below 200hz.  do you have beaming problems with the iris system?

have you considered damping the back of the frames or adding felt to the inside of the frames?   thanks   david sundby   sundbyd@comcast.net

Guys - check out these drop dead beauties courtesy of Darrel http://perfect8.com/

Darrel who?  Not Darrel Hawthorne I'm sure.  Nothing worse than unachievable claims.  They're pretty though, but I bet obscenely priced.

Richard,

Perhaps I'm too much a product of my environment and upbringing.  Have always lived in cold, economically depressed Michigan; raised on a farm where we learned hard work and thrift; and work as an engineer with the first 8 years doing structural engineering (folks do so hate when buildings collapse on them).  For the last 17 years I've worked to insure the safety and well being of users of healthcare facilities.  

We just completed building a new house and the experience was draining to say the least.  But it did include a listening room that I'm pleased with.  So my audio goal for this year is to add room treatments, however I'm currently in the middle of equipment changes (mostly involving migrating to audio PC).

JohnCR,

O.B. is only my 2nd favorite speaker type.  I've had a 28 year old love affair with transmission line designs.  My speakers mass loaded transmission lines that use single Fostex F200A full range drivers that I commissioned Bob Brines to build the first FTA-2000s.  Just today I found out that HG Dave (from the Decware forums) has the Silver Iris that he has mounted in OBs and he only lives an hour from me.  So I hope to visit him soon for an audition.  And not so long ago it was reinforced to me how good the F200As are in OB, so who knows?  

I still embrace the single driver ideal and I've found no way to do it better than with the FTA-2000s.