Post by: [x] on October 13, 2004, 07:59:28 PM
P-Audio SD-21
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.
Post by: Dietrich Sider on October 13, 2004, 11:30:52 PM
Why aren't 21" drivers used more often for subwoofers?
1) size and weight - 21" loudspeakers are HEAVY and need a bigger, stronger box - this impacts load crew and truck pack. The one you show from P-Audio weighs in at 68 lbs just for the driver - about double the weight of most 18" speakers
2) they cost significantly more than the 'industry standard' 18" drivers or boxes.
3) reliability? couldn't tell you as I've never owned one - maybe someone else has some facts and figures or a personal experience. I would have to say though that they have yet to prove themselves in the market.
4) performance - I've heard several people argue that 21" subs are not the nicest sounding boxes - they lack clarity or punch. Sure, they go low, but they don't give the sound that most live audio engineers are looking for.
There ya go . . .
Post by: Graeme Goodacre [Centauri on October 14, 2004, 08:03:12 AM
You also mention 18s as "industry standard" - this only comes about from the thinking that "bigger must be better (deeper)" and is actively encouraged by speaker manufacturers marketing departments. EAW's top performance sub uses 12s....
Cheers
Post by: Mike {AB} Butler on October 14, 2004, 11:45:50 AM
| BHFProfessional wrote on Wed, 13 October 2004 16:59 |
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? |
Simple answer. Transient response. An 18" woofer is commonly considered the largest size woofer that will effectively reproduce transients. The larger the cone surface area, typically thicker material is required to make the cone rigid enough to withstand the immense push of the voice coil.
EV had their 30" woofer 20+ years ago (Mitsubishi and possibly others had King Size woofers as well), and it put out some IMPRESSIVE low end. But no punch. Notice it isn't widely used or available anymore?
It IS possible that through new materials that these guys have overcome this issue - but I don't believe it..
Regards,
Mike
Post by: Jim Brooks on October 14, 2004, 12:40:45 PM
But there is an awful lot of
Turbosound TSW-21 cabinets out there
for something that 's not supposed to work so well.
Just a thought,
Jim Brooks
Post by: John Roberts {JR} on October 14, 2004, 02:03:52 PM
JR
Post by: Mikael Holm (the old one) on October 14, 2004, 07:14:41 PM
| JR wrote on Thu, 14 October 2004 21:03 |
21" will work OK within their bandpass but you will probably use another smaller woofer above them. |
Up to 150Hz w/ Flashlight and 180Hz w/ Floodlight. OTOH Turbo recommend TSW-718 (double 18") w/ Floods because of the upper limit of the bandpass horn.
Post by: Mikael Holm (the old one) on October 14, 2004, 07:18:05 PM
| jbrooks wrote on Thu, 14 October 2004 19:40 |
But there is an awful lot of Turbosound TSW-21 cabinets out there for something that 's not supposed to work so well. |
I remember seeing a figure of over 3000 Turbosound Flashlight TFS-780H sold so there must be AT LEAST 3000 TFS-780L boxes laying around somewhere. Add to that the sister box TSW-721 (without flyware) and we are counting some huge numbers of 21" drivers being in use today.
Post by: Tim Padrick on October 14, 2004, 09:16:50 PM
| Quote: |
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. The larger the cone surface area, typically thicker material is required to make the cone rigid enough to withstand the immense push of the voice coil. EV had their 30" woofer 20+ years ago (Mitsubishi and possibly others had King Size woofers as well), and it put out some IMPRESSIVE low end. But no punch. Notice it isn't widely used or available anymore? It IS possible that through new materials that these guys have overcome this issue - but I don't believe it.. Regards, Mike |
Nope. The rise time of the signals produced by subs is very long (in other words, the signals are "slow"). Driver speed is just not an issue. If subwoofer 'A' "sounds faster" or "has more punch" than subwoofer 'B', it is almost certainly because of one of the following:
'A' is producing more distortion than is 'B'. The distortion products are more audible than the fundamental frequency. Most PA subs are junk - 40Hz in at a decent level gives as much 80Hz and 160Hz out as 40Hz out. (Many Hi-Fi subs aren't a lot better.)
'A' has better phase/time alignment to the rest of the system than does 'B'. Owing to the various box designs and the crossover and EQ filters, subs require that the top boxes be delayed to the subs to align the boxes properly. (My subs are front loaded, and I have to delay the tops 12.5 feet to line them up. It makes quite a differenc.)
'B' has a badly tuned port (or a badly designed horn) and is resonating excessively (it is 'ringing' or has a lot of 'overhang').
Post by: Scott Shaw on October 14, 2004, 11:19:21 PM
Scott
Post by: Baron Gray on October 15, 2004, 05:46:49 AM
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
Post by: David A. Parker on October 15, 2004, 08:44:34 AM
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.
Post by: David A. Parker on October 15, 2004, 08:56:41 AM
Post by: Elliot Thompson 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 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,
Post by: Chris Cowley on October 15, 2004, 12:47:15 PM
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.
Post by: Dave Barnett 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?????
Post by: John Roberts {JR} on October 17, 2004, 11:13:23 AM
| Dave Barnett wrote on Sun, 17 October 2004 10:02 | ||
What kind of transients make it through a low-pass filter????? |
Very large ones ....
JR
Post by: bgavin (Bruce Gavin) on October 18, 2004, 11:20:49 AM
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.
Post by: Greg Bass on October 18, 2004, 08:41:03 PM
Cheers1
Scred
Post by: Noel Bennett on October 18, 2004, 09:46:00 PM
Post by: Noel Bennett on October 18, 2004, 09:49:12 PM
Post by: bgavin (Bruce Gavin) on October 19, 2004, 02:08:35 PM
Post by: Mikael Holm (the old one) on October 28, 2004, 11:15:50 AM
| D. Parker wrote on Fri, 15 October 2004 15:44 |
Note the 113 DB sensitivity at 1w/1m. BUTTT!!!!! |
As was said that sensitivity is at 100Hz. They are 8dB down from that at ~30Hz. It's useless to quote the sensitivities outside the bandpass they are used.
Post by: Mikael Holm (the old one) on October 28, 2004, 11:48:23 AM
| D. Parker wrote on Fri, 15 October 2004 15:56 |
I believe one of the advantages of the bassist having 10's onstage is that the 10's are easier to hear up close. |
Yup and that is because smaller cones usually have better response where it really counts iow. in the 1kHz and up range (definition is in the 2-5kHz range).
| Quote: |
A bassist standing near his stage rig cannot hear the lower freqs an 18 puts out. |
BS. It's because they have it directed to their legs. In the 2-5kHz range they have serious directivity and that's why they must be cranked higher.
| Quote: |
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. |
Nope. A soundwave does not need any distance to develope. See above for the explanation. 10" woofers has less directive response at upper frequencies so you don't have to turn then so loud.
Besides quad 10" cabinets are not that better than very large woofers. They have serious directivity and destructive interference up where the definition is -> bassplayer turn them louder. That's the real reason why FOH engineers have hard time with bassplayers.
| Quote: |
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. |
It's about the feel. Boost HF and see what happens.
Post by: AxeSlash on October 29, 2004, 08:07:10 PM