ProSoundWeb Community

Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => SR Forum Archives => LAB Subwoofer FUD Forum Archive => Topic started by: Chris Coleman 2 on March 05, 2006, 04:28:01 pm

Title: LAB vs Tuba32... weight vs cost
Post by: Chris Coleman 2 on March 05, 2006, 04:28:01 pm
Hey guys,

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
Title: Re: LAB vs Tuba32... weight vs cost
Post by: Al Limberg on March 05, 2006, 04:41:57 pm
I can't help you with the weight of a Tuba, but depending on materials (type of plywood, epoxies, etc.) a Lab typically weighs in between 240 and 275.  A regards the drivers, I've been running Labs since the first batch of drivers became available.  I have had two failures and both were determined by Eminence to be manufacturing faults ( the first was a shorted coil, the second a matter of adhesives.  In neither case did the mating speaker suffer any damage within the same cabinet.  On the other hand, when the first one went, it was an end cabinet in a row of four standing on end, side by side.  I opened the chamber cover and found the driver to be moving as much as if it were still being driven.  Talk about coupling!

?;o)
Al
Title: Re: LAB vs Tuba32... weight vs cost
Post by: peter.golde on March 05, 2006, 07:09:54 pm
For more Tuba info ask here
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 Twisted Evil
Title: Re: LAB vs Tuba32... weight vs cost
Post by: bgavin (Bruce Gavin) on March 05, 2006, 09:28:34 pm
This is what I have so far:

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
Title: Re: LAB vs Tuba32... weight vs cost
Post by: Chris Coleman 2 on March 06, 2006, 02:55:03 pm
Thanks guys for the responses!

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..??  

Title: Re: LAB vs Tuba32... weight vs cost
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 ??
If your system is already set up for powered speakers this may simplify your cabling runs, but if not, you will have to provide a power distribution system that gets power to everywhere you have a speaker instead of just to an amp rack. Remember there will now be 2 cables to every speaker.

Mac
Title: Re: LAB vs Tuba32... weight vs cost
Post by: Chris Coleman 2 on March 06, 2006, 03:53:33 pm
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
Title: Re: LAB vs Tuba32... weight vs cost
Post by: Randy Pence on March 06, 2006, 04:01:27 pm
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.
Title: Re: LAB vs Tuba32... weight vs cost
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

Absolutely! My point was that you will have to factor in that kind of power and signal distribution. If your system is set up with a big power feed to an amp rack, you will have to re-task it to distribute directly to the speakers. Where the stack may have had a couple of NL8s going to it in the past, it will now have power distribution plus maybe a 6 pair multi.

Mac
Title: Re: LAB vs Tuba32... weight vs cost
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.
The Meyer Veam system is great for onstage monitors, because it cleans up the cable clutter of separate signal and power to all those powered wedges onstage. It is however an expensive and inflexible system. You have to have a combination signal and power system set up with the right number of feeds, and you will have a Veam cable for every speaker. In the Meyer system, there is power, signal, and a cable pair for the Meyer RMS system monitoring and control computer.

Mac
Title: Re: LAB vs Tuba32... weight vs cost
Post by: Pascal Pincosy on March 06, 2006, 04:21:57 pm
Another consideration is that your overall costs will rise with the addition of each sub. Consider that you need to purchase the proper-sized amp for each cabinet. Add in the amount of time to properly mount the amps, and custom-build input panels. Then multiply for each cabinet. How much more is it going to cost you than buying one amp, a rack, and some cables? And are you really going to save setup time by doing this (per Mac's post?)
Title: Re: LAB vs Tuba32... weight vs cost
Post by: Chris Coleman 2 on March 06, 2006, 06:08:37 pm
True it may not save a LOT of money or time, but there are possibly some other benefits....

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 ??
Title: Re: LAB vs Tuba32... weight vs cost
Post by: Bogdan Popescu on March 06, 2006, 06:59:00 pm
I use LAB's for a few years now. Could not be happier about my decision and never thinking on changing them for any tuba or other  sub except maybe for some other of Tom's creations.

Also i would not add another kilo to the weight Very Happy some people here shore know why Very Happy

B.P.
Title: Re: LAB vs Tuba32... weight vs cost
Post by: Rick Powell on March 11, 2006, 12:26:49 am
www.speakerpower.net

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
Title: Re: LAB vs Tuba32... weight vs cost
Post by: Tom Herr on March 11, 2006, 06:41:50 am
1000 watts per sub. Can't speak for the Tuba but that would tickle a labhorn and get you some sound but no where near it's potential. I feed my labhorns with 1 RMX 2450 or PLX2402 bridged per labhorn. Never had a driver or amp failure. Started out running them this way, and never looked back. Just make sure your processor settings are correct, especially the hp filter.



Title: Re: LAB vs Tuba32... weight vs cost
Post by: Craig Leerman on March 11, 2006, 12:38:37 pm
The LAB sub was designed to be used in large systems, where size and weight is usually not an issue (large trucks, loading docks, lots of labor, etc) It uses 3/4 Plywood, as well as heavy aluminum plates as the port covers. Expects a Lab to weigh in at 250 - 300 lbs depending on finish and grill options.

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.

Title: Re: LAB vs Tuba32... weight vs cost
Post by: Chris Coleman 2 on March 12, 2006, 03:26:05 pm
Rick and Tom: good thoughts.. With the new bassmaxx subs being active designs, is the DIY world ready for a powered lab sub using something like a speakerpower 2ch plate amp at 1000w/ch including integrated dsp crossover ??

Craig: do you think an active tuba would be more of a hot item than an active lab ?
Title: Re: LAB vs Tuba32... weight vs cost-speakerpower
Post by: Ivan Beaver on March 12, 2006, 04:45:34 pm
The problem with the Speakerpower solution for subs is in the max output available.  This is not saying anything bad about them, you just have to look at the REAL numbers.  The dual 1000w module is 1000w per channel @4 ohms.  It is like 660W or so at 8 ohms.  Don't make the assumption (like I did) that you can bridge the outputs into a single loudspeaker.  The outputs are already bridged so that is all the power that is available.  For serious subs that is a wee bit shy of what is needed.  Of course it keeps them from getting overpowered.  The DSP has a limiter to keep the clipping down, but to really push the performance of modern day subs, you need more power, or possibly go to 4 ohm drivers.  In a situation such as a lab sub, the speakerpower solution might be pretty good, with a channel driving each speaker.  You would have around 700-800W /driver, which is not bad, but still shy of what you would put on it, if you were to put an outboard amplifier on it.
Title: Re: LAB vs Tuba32... weight vs cost
Post by: Chris Coleman 2 on March 12, 2006, 06:08:48 pm
Ivan: very true, for 8 ohms at 800w you're only getting 80volts (instead of 88 volts from 1000w at 8 ).  Do you know of a plate amp that would be better match the Lab sub, offering 1000w into 8 ohms..?!
Title: Re: LAB vs Tuba32... weight vs cost
Post by: Ivan Beaver on March 12, 2006, 06:31:42 pm
Considering that the Lab 12 is rated for 400watts, you can add 3 to 6 dB to that figure (depends on how you want to count) and end up with 800-1600Watts as the proper power to be AVAILABLE to the speaker-not to be used continously.

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. Laughing
Title: Re: LAB vs Tuba32... weight vs cost
Post by: Antone Atmarama Bajor on March 12, 2006, 06:52:35 pm
89.44VRMS = 1000W @ 8 Ohms

88 is close ~1%.   Very Happy

Antone-
Title: Re: LAB vs Tuba32... weight vs cost
Post by: Chris Coleman 2 on March 12, 2006, 06:58:28 pm
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!  Laughing
Title: Re: LAB vs Tuba32... weight vs cost
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!  Laughing

Could you post a link to where it said less than .5ms of latency? It seems highly unlikely that you could do an analog to digital conversion, run it through the DSP, and then do a digital to analog conversion in less than .5ms. It might be less than .5ms through the DSP, but I think the 2 conversions are going to be more than that.

Mac
Title: Re: LAB vs Tuba32... weight vs cost
Post by: Chris Coleman 2 on March 12, 2006, 07:20:15 pm
Sure Mac, the link for the latency spec is here:

http://speakerpower.net/Specifications%20SP.pdf

"460 microseconds"

I guess it's a nice high sample rate converter !

Title: Ivan, any idea?
Post by: Mac Kerr on March 12, 2006, 07:36:37 pm
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
Title: Re: LAB vs Tuba32... weight vs cost
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.
Title: Re: Ivan, any idea?
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
Title: Re: Ivan, any idea?
Post by: Ivan Beaver on March 12, 2006, 07:56:21 pm
I have no idea and have not actually measured it Embarassed .  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.
Title: Re: Ivan, any idea?
Post by: Mac Kerr on March 12, 2006, 08:06:23 pm
Ivan Beaver wrote on Sun, 12 March 2006 19:56

I have no idea and have not actually measured it Embarassed .  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.
Thanks, I know that Optocore specifies 69 samples for the analog to digital to analog conversion process. This is 720
Title: Re: LAB vs Tuba32... weight vs cost
Post by: Chris Coleman 2 on March 12, 2006, 08:37:11 pm
Antone Atmarama Bajor wrote on Sun, 12 March 2006 18:52

89.44VRMS = 1000W @ 8 Ohms

88 is close ~1%.   Very Happy



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 ??
Title: Re: LAB vs Tuba32... weight vs cost
Post by: Antone Atmarama Bajor on March 12, 2006, 11:35:19 pm
Yah the quick and dirty equation is V=(SQR)(P*R)

    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-
Title: Re: LAB vs Tuba32... weight vs cost
Post by: Magnus "Magic" Johansson on March 23, 2006, 08:07:03 am
Chris Coleman 2 wrote on Mon, 13 March 2006 01:08

Ivan: very true, for 8 ohms at 800w you're only getting 80volts (instead of 88 volts from 1000w at 8 ).  Do you know of a plate amp that would be better match the Lab sub, offering 1000w into 8 ohms..?!



This should about do it : 2000W into 4 ohms
http://www.cadaudio.dk/pwmaudio_en.htm