8 small woofers vs 1 large one

[ligs]

Is there any merit of using 8 small woofers vs a large one as seen in the following link.

http://www.hartaudio.com/EVO1+Review.html

more defined bass or just marketing trick?

[ligs]

Re: 8 small woofers vs 1 large one

Here is the photo. Sweet 16 for two channels?

[johnnyrichards]

Re: 8 small woofers vs 1 large one

Sd + Xmax is what determines output potential, so unless the multiple small drivers have the displacement of a larger driver, than there are no output advantages.

Also, small drivers (no matter how many) generally cannot go as low as a large driver. So this also has to be considered.

[ligs]

Re: 8 small woofers vs 1 large one

David Hart, the designer calculates that these eight drivers are equivalent in area to a 330mm cone but the combined magnet power is equal to a 300mm magnet. So imaging a 330 mm cone with a 300 mm magnet, you have a lot of magnetic forces at play.

And 8 woofers each with one inch VC are equal to a 8-inch VC!

[Guest]

Re: 8 small woofers vs 1 large one

And 8 woofers each with one inch VC are equal to a 8-inch VC!

Nope.

[billfitzmaurice]

Re: 8 small woofers vs 1 large one

David Hart, the designer calculates that these eight drivers are equivalent in area to a 330mm cone but the combined magnet power is equal to a 300mm magnet. So imaging a 330 mm cone with a 300 mm magnet, you have a lot of magnetic forces at play.

And 8 woofers each with one inch VC are equal to a 8-inch VC!

There are some advantages to using multiple smaller drivers, but they way it's done here I'm afraid not. There's a major disadvantage, and that's cost. One large driver with the same displacement limited output would be considerably less expensive than the eight smaller drivers. That fact, combined with a number of fallacious statements in the ad copy/review, makes it a gimmick IMO. If doing this really worked well Bose 901s would sound good. And I think not coincidentally those drivers appear to be sourced from the same place as 901 drivers.

[ligs]

Re: 8 small woofers vs 1 large one

Very keen observation. These woofers do look like big brothers of Bose 4.5 inch full range

[Paul K.]

Re: 8 small woofers vs 1 large one

While multiple drivers do, indeed, have a combined Sd equal to the sum all of the individual driver's Sd, a small driver is very likely to have an equally small Xmax, and the Xmax of the combined drivers will be no larger than that of single driver. Plus, the combined drivers will still have the same bass response in terms of frequency as a single driver. Now if each driver has an Xmax of 6 mm and can play 30 Hz well, that would be a different story.
Paul

David Hart, the designer calculates that these eight drivers are equivalent in area to a 330mm cone but the combined magnet power is equal to a 300mm magnet. So imaging a 330 mm cone with a 300 mm magnet, you have a lot of magnetic forces at play.

And 8 woofers each with one inch VC are equal to a 8-inch VC!

[billfitzmaurice]

Re: 8 small woofers vs 1 large one

Very keen observation. These woofers do look like big brothers of Bose 4.5 inch full range

115mm is 4.5 inches. The triangular shape is fairly unique to Bose AFAIK, until now anyway.

[ligs]

Re: 8 small woofers vs 1 large one

Further searching for speakers with multiple drivers led me into this link:

http://www.roger-russell.com/columns/columns.htm

"My Experience with Column Systems
and how It lead to the creation of the unique, single full range column"

Higher efficiency(up to 10 db) and coherent sound have been claimed for stereo speaker columns with 25 drivers in each column. Interesting reading anyway

[greywarden]

Re: 8 small woofers vs 1 large one

Wow I just read that whole article, Fantastic!

I did a spreadsheet a while back for linearrays, for the cheaper buyouts and I decided the cheapest and most efficient of them was the JAMO 20489. Of course, they're not full range, just "extended range" and wouldn't exactly do the job.

[ligs]

Re: 8 small woofers vs 1 large one

The reason I became interested in projects using multiple drivers was due to the availability of PE's Klipsch 6.5 buyout. One advantage of using multiple drivers is you can avoid the floor bounce cancellation. Most linesource columns use small drivers(2-4 inches), I just wonder can you have wwwwwwttttttttwwwwww kind of arrangement so the highs are coverered by the smaller diameter tweeters?

[billfitzmaurice]

Re: 8 small woofers vs 1 large one

Further searching for speakers with multiple drivers led me into this link:

http://www.roger-russell.com/columns/columns.htm

Old news even as of the date published.
AFAIK the first major installation was St.Paul's Cathedral, London, circa 1949, and that's only AFAIK.
The benefits of line sources have been known by the professional community since the mid 1930s. Acceptance of these benefits by the lay community has been sporadic at best, as they don't understand that horizontal dispersion is inversely proportional to the width of the radiating plane.

[ligs]

Re: 8 small woofers vs 1 large one

I realized there has been a big gap between commercial sound and the sound at home. From your vantage point, can you give us your take on using arrayed speakers in a home setting. I was very impressed by the music performance at 2010 EXPO in Shanghai, where multiple arrays of speakers of various sizes hanging over your head. The sound was good on solo as well as big musical numbers.

[billfitzmaurice]

Re: 8 small woofers vs 1 large one

I realized there has been a big gap between commercial sound and the sound at home. From your vantage point, can you give us your take on using arrayed speakers in a home setting.

This is my livingroom: