Post by: Chris Coleman 2 on March 05, 2006, 04:28:01 PM
I'm looking at building four either Tuba 32 or Lab subs.
I heard that one LAB sub is very heavy. In comparison..how much does a Tuba 32 weigh ??
Also.. I notice that lab drivers for one cabinet come to about $300, ie two per cabinet at $150 each, and that when one blows, they both blow because of the physics of the high pressure cavity they are in. What is the price of the drivers in a Tuba?? How much do recone kits cost for lab vs tuba ??
Love y'all
Chris
Post by: Al Limberg on March 05, 2006, 04:41:57 PM
?;o)
Al
Post by: peter.golde on March 05, 2006, 07:09:54 PM
http://audioroundtable.com/BillFitzmaurice/
I have built and used both the Lab and a Tuba30s.
The Labs are more expensive to build (aluminum plates), are larger and less portable, they are designed to be used in groups of four or more for full horn loading to 32Hz. I only used a pair of Labs, and the output was clean and powerful. The Tuba is designed to be more portable. There are several different configurations you can build to suit your needs, including single or dual 12's or 15's. The Tuba has a smaller horn mouth area, but is different than the Lab in that it takes advantage of the driver running below Fc into direct radiator mode. The larger rear chamber and the path length serve to lower the driver Fs, so a driver with a higher resonant frequency works better in the Tuba. This allows a wide range of pro sound drivers to work well. If better horn loading down low is desired, add more boxes.
The Lab is a world class touring sub, which you may or may not need, or may not be able to use to it's full potential. It all depends on your intended use. A small band putting together their own sound system would be foolish to build a Lab, but a Tuba makes perfect sense. If you are providing outdoor raves, build 8 or more Labs
Post by: bgavin (Bruce Gavin) on March 05, 2006, 09:28:34 PM
Tuba24 - 61 pounds - 1/2" baltic birch, no driver, no finish, no hardware
Tuba24 - 64 pounds - HL10 with finish and casters, Oak plywood
Tuba24 - 63 pounds - Beta 10,
Tuba30 - 84 pounds - 26" wide. 18mm ply outer, 14mm inner, Delta 12LF
Tuba30 - 124 pounds - 30" cube, JBL 2206H
Tuba36 - 150 pounds - estimated
Post by: Chris Coleman 2 on March 06, 2006, 02:55:03 PM
Follow up question:
1) Has anyone here ever made an "active" version of this LAB sub or the Tuba sub ?? This way you could eliminate separate amp racks, add only about 50 pounds to each sub, and simplify your cabling runs by turning it into an active sub, fed with a simple balanced xlr subwoofer signal direct from your driverack or other crossover. What power amp did you mount inside the sub ??
I imagine by mounting the amp inside, you have to be certain not to alter the airflow in the horn.
2) How would you modify the design to mount a power amp "inside" the sub cabinet..??
Post by: Mac Kerr on March 06, 2006, 03:10:49 PM
| Chris Coleman 2 wrote on Mon, 06 March 2006 14:55 |
1) Has anyone here ever made an "active" version of this LAB sub or the Tuba sub ?? This way you could eliminate separate amp racks, add only about 50 pounds to each sub, and simplify your cabling runs by turning it into an active sub, fed with a simple balanced xlr subwoofer signal direct from your driverack or other crossover. What power amp did you mount inside the sub ?? |
Mac
Post by: Chris Coleman 2 on March 06, 2006, 03:53:33 PM
Couldn't you combine things a bit so that you have each "stack" being fed by (for example) :
1) One thick 60 amp AC power feed.. split up into four 15 Amp circuits.. four subs + four tops per stack, one 15 Amp circuit per sub + top.
2) 0ne subwoofer signal on a balanced xlr.. goes to the subs and is "daisy chains" from one sub to the next.
3) One midrange +
4) ... one tweeter signal. On balanced xlr's.. goes to the tops which have one two-channel amp per box. Daisy chain from box to box in the stack.
Chris
Post by: Randy Pence on March 06, 2006, 04:01:27 PM
Post by: Mac Kerr on March 06, 2006, 04:06:12 PM
| Chris Coleman 2 wrote on Mon, 06 March 2006 15:53 |
Mac good point. Couldn't you combine things a bit so that you have each "stack" being fed by (for example) : 1) One thick 60 amp AC power feed.. split up into four 15 Amp circuits.. four subs + four tops per stack, one 15 Amp circuit per sub + top. 2) 0ne subwoofer signal on a balanced xlr.. goes to the subs and is "daisy chains" from one sub to the next. 3) One midrange + 4) ... one tweeter signal. On balanced xlr's.. goes to the tops which have one two-channel amp per box. Daisy chain from box to box in the stack. Chris |
Mac
Post by: Mac Kerr on March 06, 2006, 04:10:33 PM
| Randy Pence wrote on Mon, 06 March 2006 16:01 |
A lot of meyer users use cable that carries both power and signal in one bundle. Sending both changes things, but there are enough active speakers out there that its not impossible. |
Mac
Post by: Pascal Pincosy on March 06, 2006, 04:21:57 PM
Post by: Chris Coleman 2 on March 06, 2006, 06:08:37 PM
Like what about using active power amps that have a built in "cone position sensor" circuit to provide true driver excursion protection + overheat protection + dynamic EQ ?? Did you ever try such an advanced power amp inside DIY LAB sub or inside a matching top enclosures ??
Post by: Bogdan Popescu on March 06, 2006, 06:59:00 PM
Also i would not add another kilo to the weight
some people here shore know why B.P.
Post by: Rick Powell on March 11, 2006, 12:26:49 AM
These "plate" amps might do the trick, the 1000w at 4 ohms version looks like the ticket for a sub. They only draw about 2 amps, too.
RP
Post by: Tom Herr on March 11, 2006, 06:41:50 AM
Post by: Craig Leerman on March 11, 2006, 12:38:37 PM
Bill's Tubas OTOH were designed to be portable! His cabinets use 1/2 plywood and were designed mainly for use by local folks who have to move their own stuff around. While I don't know what his stuff weighs, I can tell you that your back will love a Tuba over a LAB sub anyday!
If you are playing clubs, I think Tubas would be a good choice. A LAB is a bit large and heavy.
In addition, some of Bill's designs have options to use 1 or 2 drivers per box. That would save some money on drivers. His TUBA SLIM with 1 X 15" per box seems to be popular.
Post by: Chris Coleman 2 on March 12, 2006, 03:26:05 PM
Craig: do you think an active tuba would be more of a hot item than an active lab ?
Post by: Ivan Beaver on March 12, 2006, 04:45:34 PM
Post by: Chris Coleman 2 on March 12, 2006, 06:08:48 PM
Post by: Ivan Beaver on March 12, 2006, 06:31:42 PM
The Speaker power amp would drive it pretty good, but if you want the last couple of db out of it, it would be shy. But the limiter could take care of those small peaks and you would probably never know the difference in level-only clipping on the external amp-if allowed to do so.
The biggest issue with the Speakerpower DSP is the actual programming. IT AIN'T your normal DSP-Far from it. It is a TI design-so that should give you an idea. It is FAR from being real time and can get confusing. I know enough to barely get around on it. But at least it keeps people from messing with it.
Post by: Antone Atmarama Bajor on March 12, 2006, 06:52:35 PM
88 is close ~1%.
Antone-
Post by: Chris Coleman 2 on March 12, 2006, 06:58:28 PM
Post by: Mac Kerr on March 12, 2006, 07:10:21 PM
| Chris Coleman 2 wrote on Sun, 12 March 2006 18:58 |
Ivan: yeah it said under a half millisecond of latency in the speakerpower dsp, which should make no difference to the sound but you can compensate for it with an external processor by delaying the tops. Don't they have an easy interface for adjusting the dsp programming ?? I guess Behringer is better than them, then! |
Mac
Post by: Chris Coleman 2 on March 12, 2006, 07:20:15 PM
http://speakerpower.net/Specifications%20SP.pdf
"460 microseconds"
I guess it's a nice high sample rate converter !
Post by: Mac Kerr on March 12, 2006, 07:36:37 PM
Post by: Craig Leerman on March 12, 2006, 07:37:35 PM
| Quote: |
Craig: do you think an active tuba would be more of a hot item than an active lab ? |
Depends on what your definition of a "hot item" is.
First, I'm not sure there is a small enough size amp unit with large enough power available to convert a LAB. And if there was, I don't think there is a large market segment of those who use Labs (or other large concert sized subs) that would switch from the racks of amps and cabling that they already own and use, to built in amps. So, for the Lab sub, I don't think built in amps are going to be a hot item.
As for the Tubas, it may be a better fit. Bill's designs require less power, and there are a bunch of available small amps that could be built into his cabinets. In fact, there is a guy on his forums that turned his small monitors into self powered units!
For a guy lugging stuff into a club or other small venue, self powered cabinets have a lot to offer. They don't add that much weight to a cabinet, but cut out a lot of weight from an amp rack. In addition, they eliminate having to find a place for the amp rack on a small stage, and in a small truck or trailer.
Personally, I'm not a big fan of self powered cabinets. The only benefit I like about them is the fact that a good manufacturer can install amps and electronics perfectly matched to the cabinets drivers, and get the most out of the box. But, today, with cheap DSP X/Over units like the Driverack stuff readily available, and some signal testing gear (like PC based Smaart) most folks can get the same level of quality out of any box and amplifier combo.
My main dislikes are the fact that you have to run BOTH Signal and Power to each cabinet, and if the amp dies in a cabinet, that entire cabinet is now out of service. In a standard unpowered speaker/seperate amplifier setup, you can always jump around a dead component (like and amp channel) or substitute a spare amp.
My other dislike is that unless you are starting out, you already have a big investment in amplifiers, racks, speaker cables, etc that are now obsolete if you buy powered cabinets. But, if I stay with unpowered cabs, I can always upgrade cabinets and keep my amps, cables, etc OR I can upgrade amps without having to buy new cabinets! More flexible to me.
Post by: Mark Seaton on March 12, 2006, 07:48:16 PM
| Mac Kerr wrote on Sun, 12 March 2006 18:36 | ||||||
So Ivan, you've actually used these things, and you're usually on top of specs that don't meet spec, do you have any idea how they get the latency down to 460 Post by: Ivan Beaver on March 12, 2006, 07:56:21 PM  . The only cabinets that I have been using them (so far) is in home theatre subs. I will ask Brian about it and find out. I am swamped untill NSCA, so I will talk to him there.
Post by: Mac Kerr on March 12, 2006, 08:06:23 PM
Post by: Chris Coleman 2 on March 12, 2006, 08:37:11 PM
Antone: Good point.. so 1000w makes about 11% more voltage than 800w. Is excursion linearly related to voltage.. or to the square root or log of voltage ?? Post by: Antone Atmarama Bajor on March 12, 2006, 11:35:19 PM Ever wonder where that 2.8xx VRMS @ 1 meter comes from. Its supposed to represent 1 W at 1 meter @ 8ohms but a lot of companies try to spec a lower Z driver with the same voltage level to try and pass it off as being more efficient. Antone- Post by: Magnus "Magic" Johansson on March 23, 2006, 08:07:03 AM
This should about do it : 2000W into 4 ohms http://www.cadaudio.dk/pwmaudio_en.htm |