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Author Topic: 21" Cones - Why Not?  (Read 10914 times)

Baron Gray

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Re: 21" Cones - Why Not?
« Reply #10 on: October 15, 2004, 05:46:49 AM »

Yup and that's why guitar players seem to go for the old 12" and Bass players opt for the 8 or 10s in their quad or octa boxes.

It is all about personal preference and I like my bass tight and punchy and all the 12s I have tried sounded a bit fuzzy around the edges compared to the 10s.

Baron
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David A. Parker

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Re: 21" Cones - Why Not?
« Reply #11 on: October 15, 2004, 08:44:34 AM »

Ah, the KF940 Supersub. I experienced those once, it was unforgetable. It was an outside festival, I parked a half mile from the stage, and the bass was tight when I got out of the car. A quote from the eaw website

Description
The KF940 portable horn-loaded subwoofer system, otherwise known as the "Super-Sub," has created a new level of sub bass performance by loading two specially designed 12 in woofers with a horn with an exponentially expanding throat that is over 13 ft long. Great care has been taken to create woofer cones that could withstand the force of being loaded with such a large horn. As an impedance matching device, the horn brings the 1 watt @ 1 meter sensitivity of the system at 100 Hz to 113 dB SPL.

Note the 113 DB sensitivity at 1w/1m. BUTTT!!!!! You need a forklift with each cab weighing 360# !!!! AND!! EAW sells a lot more double 18's, THE INDUSTRY STANDARD (for whatever reason), than the KF940's.
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David Parker
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David A. Parker

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Re: 21" Cones - Why Not?
« Reply #12 on: October 15, 2004, 08:56:41 AM »

But then what the audience actually hears, coming from the mains, is coming from a combinations of drivers, usually starting with 18's. So, what you are hearing onstage from your 10's can never be exactly what the audience is hearing. I am a sound man and bassist, and I believe one of the advantages of the bassist having 10's onstage is that the 10's are easier to hear up close. A bassist standing near his stage rig cannot hear the lower freqs an 18 puts out. They develop out farther in the room and the sound guy has to deal with them. 10's do this too, but not nearly as bad. One thing I noticed early on in this business is that to satisfy the bassist onstage, (me included), the stage rig will be pretty much filling the room with bass. AND, it doesn't matter if the bassist doesn't have a rig onstage, if he only has wedges, when I get the wedges cranked enough to make the bassist happy, the wedges are filling the room with bass.
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Elliot Thompson

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Re: 21" Cones - Why Not?
« Reply #13 on: October 15, 2004, 10:14:43 AM »

BHFProfessional wrote on Thu, 14 October 2004 00:59

I see a lot of people using single and dual 18" boxes. It's like the industry standard or something, for pro sound companies to have a large inventory of dual-18" enclosures. But what I'd like to know is, why aren't 21" woofers like this one (see picture) in wider use?

P-Audio SD-21 http://www.paudio-europe.com/products/foto/foto_sd-21.jpg

This has a 6" Voice Coil (!) and extends down to 30 Hz. It also handles 1000w per driver RMS, 2000w max. A dual-12" cabinet could handle 4000 watts with just one unit.



21" woofers are limited in selection. Beyma, Precision
Devices, and, P Audio, are the only companies (To my
knowledge) that make 21" tranducers.

The Beyma is designed for a Reflex Cab {QTS 0.43}

The Precision Devices is designed for a Horn-Loaded Cab. {QTS 0.19}

The P Audio is designed for a Horn-Loaded Cab. {QTS 0.22}

So, IMHO if the QTS was around 0.3 - 0.35, you would see
Dual 21's popping up. For the extension, of a dual 18 cab,
will require a very large box, for the Beyma, and, for a
21" horn, the cabinet size will be too large, using the P
Audio, and, Precision Devices.


Best Regards,
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Elliot

Chris Cowley

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Re: 21" Cones - Why Not?
« Reply #14 on: October 15, 2004, 12:47:15 PM »

At Plasa a few weeks ago I hear the Void Static system. This used an 15" horn on bass, with 21" bandpass below it.

This was one seriously kickass rig, the best I have heard in a longtime (it looked cool as well).

I was was designed by Rog Mogale (www.speakerplans.com) who is bit of genius.
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Dave Barnett

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Re: 21" Cones - Why Not?
« Reply #15 on: October 17, 2004, 11:02:37 AM »

Mike AB wrote on Thu, 14 October 2004 10:45



Simple answer. Transient response. An 18" woofer is commonly considered the largest size woofer that will effectively reproduce transients.


What kind of transients make it through a low-pass filter?????
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John Roberts {JR}

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Re: 21" Cones - Why Not?
« Reply #16 on: October 17, 2004, 11:13:23 AM »

Dave Barnett wrote on Sun, 17 October 2004 10:02

Mike AB wrote on Thu, 14 October 2004 10:45



Simple answer. Transient response. An 18" woofer is commonly considered the largest size woofer that will effectively reproduce transients.


What kind of transients make it through a low-pass filter?????

Very large ones ....   Smile  

JR
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bgavin (Bruce Gavin)

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Re: 21" Cones - Why Not?
« Reply #17 on: October 18, 2004, 11:20:49 AM »

Looking over the numbers on the SD-21, the BL:MMS ratio (motor strength to total cone mass) is right there with the better 18" drivers, i.e. Eminence Magnum, JBL, B&C, Beyma.

However, this ratio is only half of that for high quality 15" drivers, which are reputed to have more punch.

A higher motor strength relative to cone mass provides tighter control over cone acceleration, especially for transients.  The ability to accelerate the cone faster translates into "punch" in my mind.  Hence, bass players and their love for 10" drivers.  

It would be interesting to see this on a scope.
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Greg Bass

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Re: 21" Cones - Why Not?
« Reply #18 on: October 18, 2004, 08:41:03 PM »

A club I work at regularly has some old Turbo stuff -early 80's maybe late 70's.  Two of the subs have 21" or 24" drivers and the other two have 15"'s I believe. All in horns. Substantial low end.

Cheers1

Scred
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Noel Bennett

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Re: 21" Cones - Why Not?
« Reply #19 on: October 18, 2004, 09:46:00 PM »

A friend of mine has a single P Audio 21 in a bandpass box that is significantly smaller than any 2x18 sub I have ever seen . They are in an instillation with one sub a side with 2x 15 and 2coaxial P audio mid highs powered by lab gruppens and believe me this little rig rocks
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