[donw]

Some time ago I built a pair of open baffle speakers based on Hawthorne Audio 15" drivers. Each side had 2 x 15" woofers for the lows, a 15" driver for the mid range, and the short lived Hawthorne Audio AMT 700s for the highs. The baffles measured 5 ft. tall by 24 in. wide and they were extremely stiff. Unfortunately for me, those speakers were destroyed by fire. I'm thinking about how to replace them.

What I absolutely loved about those speakers was how big they sounded, even at very, very low volume. They filled the room such that I felt I was listening "in" the music, as opposed to "at" it. The music was all around me. I was floating on a cloud of music. The baffles themselves were hardly there at all. In their place was a wall of sound reaching out to pull me in. I have always assumed that the large 15 in. drivers were a big part of what made that magic happen.

Lately I've been impressed in by all the very positive feedback that exists around Danny Richie's work. Of course I noticed right away that he uses small diameter drivers exclusively, mounted in thin baffles. I have been able to gather two reasons for this: smaller drivers are faster than larger drivers, and thin baffles are better for imaging because they reflect less. What I wonder is this: do these designs deliver that big sound that I loved so much in my old speakers? Do they fill the room, even at very low volumes?

I would welcome a discussion about the differences, pros and cons, of small vs. large diameter drivers in an open baffle.

Thanks in advance.

[gab]

here is a perspective:

http://www.troelsgravesen.dk/Acapella_WB.htm

"The launch of the Stradivari by Sonus Faber has created quite a debate and what has been argued against wide baffled speakers is some loss of pinpoint imaging. Here are some different views on the subject."

[Tyson]

I think it's not just big drivers but also efficiency.  Highly efficient speakers just project a liveness and engagement that low efficiency speakers don't have.  Or if they do have it, it's usually only at higher volume. 

Now, having said all that, I've had high efficiency speakers with small drivers and with large drivers.  IMO the large drivers sound better.  Especially for lower mids and upper bass. 

The other thing you have to realize is that AMT tweeter used on your old speakers was really special.  It might be the best tweeter in the world at the moment. 

However, the 2nd best tweeter (and best midrange driver) is the Neo3 and Neo10 that Danny uses in the Super 7 kits.  Those things are phenomenal.  And they are also very, very high efficiency - a true 97db. 

[Early B.]

The other thing you have to realize is that AMT tweeter used on your old speakers was really special.  It might be the best tweeter in the world at the moment. 

Yep. My speakers use Hawthorne's AMT 700 tweeters. It's the best tweeter I've heard.

OP -- consider line arrays if you want that "inside the music" sound. 

[Danny Richie]

I have been able to gather two reasons for this: smaller drivers are faster than larger drivers, and thin baffles are better for imaging because they reflect less.

Yes, that is exactly why.

In the end it is all about settling time. How fast a driver can recover and stop is a really big deal.

And when reaching down low the 12" servo subs are pretty much the kings. They are light weight and stop on a dime with that servo system controlling them. And then they play flat to the rock bottom too.

And as for the upper ranges I really do like smaller baffles. I am really into imaging, transparency, and sound stage layering and size. And the small baffle sizes do have advantages in that department.

[Folsom]

I'd love to see Danny design a driver that's 15", something like the JBL 2226H. Match with tweeters, dig to at least 40hz.

Small drivers are great for rock and roll, and jazz. But larger higher sensitivity is really better for classical.

[Wind Chaser]

Small drivers are anything but great for rock and roll. 

All music benefits from high sensitivity.

[Danny Richie]

Very small and lightweight drivers in this one. They have 98db sensitivity and dynamics out the wazoo. 

[Captainhemo]

I'd love to see Danny design a driver that's 15", something like the JBL 2226H. Match with tweeters, dig to at least 40hz.

Small drivers are great for rock and roll, and jazz. But larger higher sensitivity is really better for classical.

I know you've  done some mods to the  amps, but have you  ever heard the  servo  12's  ?     No real need for   15's,  just more mass.

jay

[S Clark]

I can assure all of you that 6 1/2" drivers can play rock and classical realistically and effortlessly. It just takes more than one.

[Captainhemo]

I can assure all of you that 6 1/2" drivers can play rock and classical realistically and effortlessly. It just takes more than one.

And,  they hardly  have to work to reach hgh SPL's.    Very little movement  and no   large moving mass of a large  driver   

jay

[glynnw]

OOOH!  Are those Design Acoustics D12 speakers in the background?

[Wind Chaser]

I can assure all of you that 6 1/2" drivers can play rock and classical realistically and effortlessly. It just takes more than one.

Yes, of course but even multiple small drivers will have LF limitations.

[S Clark]

OOOH!  Are those Design Acoustics D12 speakers in the background?

Yep.   

[S Clark]

Yes, of course but even multiple small drivers will have LF limitations.

Not necessarily.
To say that a 6.5" driver doesn't play into the 20's is incorrect.  What is true is that it may be 10 dB down from 100hz, but with enough drivers that can be accounted for in the crossover.  The only speakers I've heard that compare in accurate bass with the LS9 speakers are multiple servo subs. 

[Folsom]

Small drivers are anything but great for rock and roll. 

All music benefits from high sensitivity.

It’s so compressed that I don’t notice the difference as much between speakers.

[Folsom]

I know you've  done some mods to the  amps, but have you  ever heard the  servo  12's  ?     No real need for   15's,  just more mass.

jay

I wasn’t talking about 15” for subs, but for mids and bass.

[Norman Tracy]

In hot rodding, drag racing, and other motor sports there is a saying, it goes "there's no replacement for displacement". When making horsepower that refers to an engine's cubic inches (or liters) of air and fuel that gets pumped into and burned by the engine. When making hi-fi its about the displacement of air that speaker can move. Fifteen inch woofers, or GR's arrays, or Magnapan's big panels, or horn loading all yield the ability to easily displace a lot of air. I find that ability a primary ingredient of systems possessing a WOW factor.

Of course in hi-fi like the rest of life the devil is in the details. Each of those techniques has been done both poorly and with excellence. In my experience Danny's arrays fall into the later category. Scroll to just below this image in the linked report to read my experience with the big GR arrays at LSAF 2019 https://positive-feedback.com/show-reports/lone-star-audio-fest-2019/.

[donw]

The other thing you have to realize is that AMT tweeter used on your old speakers was really special.

Yes, the Hawthorne Audio AMT drivers were very special. It was a real shame they were discontinued after such a short run. For what it's worth, the 700s were actually the little brother to the 500s. The number indicated the recommended crossover point, such that the 700s crossed over at 700 hz. The 500s weren't available to the DIY market, or I would have used them. I wonder why there are no other AMT drivers that go so low, that I know of anyway.

I always felt that the big drivers for the lower mids and bass were a big part of that big sound. Especially at low volumes. That was important to me. All other speaker I have heard need to be played at higher volumes to achieve the same effect. But I've never heard a line array. I can easily believe a line array of smaller drivers could do the same or similar.

The HA 15 inch drivers were good but probably not the best. I always intended to replace them with AE Speakers - the LO15 for mids and Dipole15 for bass, both of which are designed for open baffle. Unfortunately I never got a chance to try that. The 12 inch servo subs do look very compelling as an alternative for the bass.

[Early B.]

Yes, the Hawthorne Audio AMT drivers were very special. It was a real shame they were discontinued after such a short run. For what it's worth, the 700s were actually the little brother to the 500s. The number indicated the recommended crossover point, such that the 700s crossed over at 700 hz.

That's correct. Thanks.