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Title: Eminence Lab 12C High Power 12" Subwoofer Speaker Driver 4 Ohm
Post by: Jeff Bailie on February 22, 2013, 10:00:22 am
Has anyone seen the new Lab 12 driver?   It says it has a 4 ohm load rating and it can handle a little more power...     

http://www.parts-express.com/pe/showdetl.cfm?partnumber=290-668
Title: Re: Eminence Lab 12C High Power 12" Subwoofer Speaker Driver 4 Ohm
Post by: Art Welter on February 22, 2013, 06:36:20 pm
Has anyone seen the new Lab 12 driver?   It says it has a 4 ohm load rating and it can handle a little more power...     

http://www.parts-express.com/pe/showdetl.cfm?partnumber=290-668

I think the 12C is aimed at  car sub use, where a single speaker with low impedance is more useful, and all they look at is power ratings.
The 500 watt Lab 12C is only 3.11 ohms DC (compared to 400 watt 4.29 ohms for the Lab 12).
In most horn and bass reflex designs the DC resistance is pretty close to the impedance minima.

At 1.55 ohms for a pair in parallel, even some 2 ohm rated amps will cough with that load.

The Lab motor is not very effective at getting rid of heat, my guess is very little (if any) output would be gained using the extra power the 12C can take, due to thermal compression.
Best case with no thermal compression given an extra 100 watts would only be 1 dB more output in the upper range, but no increase down low, as Xmax is no greater for the 12C.

Art
Title: Re: Eminence Lab 12C High Power 12" Subwoofer Speaker Driver 4 Ohm
Post by: duane massey on February 24, 2013, 11:29:16 am
But..but..Art, it's 100watts more! 100 WATTS!!!
Title: Re: Eminence Lab 12C High Power 12" Subwoofer Speaker Driver 4 Ohm
Post by: Jeff Bailie on April 22, 2013, 07:15:01 am
I think the 12C is aimed at  car sub use, where a single speaker with low impedance is more useful, and all they look at is power ratings.
The 500 watt Lab 12C is only 3.11 ohms DC (compared to 400 watt 4.29 ohms for the Lab 12).
In most horn and bass reflex designs the DC resistance is pretty close to the impedance minima.

At 1.55 ohms for a pair in parallel, even some 2 ohm rated amps will cough with that load.

The Lab motor is not very effective at getting rid of heat, my guess is very little (if any) output would be gained using the extra power the 12C can take, due to thermal compression.
Best case with no thermal compression given an extra 100 watts would only be 1 dB more output in the upper range, but no increase down low, as Xmax is no greater for the 12C.

Art

I have a few questions;

-How does an amp keep up with the 2 Ohm Load of a much more powerful Subwoofer such as a DBH218 with 2 4 ohm divers?

-Could you maybe wire all of your labhorn cabinets in series and hook up 4 of them to a single channel of a huge amp like a Lab Gruppen PLM20000q?



Title: Re: Eminence Lab 12C High Power 12" Subwoofer Speaker Driver 4 Ohm
Post by: Ivan Beaver on April 22, 2013, 07:45:13 am
I have a few questions;

-How does an amp keep up with the 2 Ohm Load of a much more powerful Subwoofer such as a DBH218 with 2 4 ohm divers?

-Could you maybe wire all of your labhorn cabinets in series and hook up 4 of them to a single channel of a huge amp like a Lab Gruppen PLM20000q?
The Danley DBH218 (and all other larger Danley subs) have a locking impedance switch on the rear panel.  It allows you to choose how you want to run the sub in YOUR application.

In the case of the DBH218-it is either a single 2 ohm load or 2x4 ohm loads.

Which ones is best for you?  It depends.  What is the music style (HUGE differences there)?  How long are the cable runs?  What type of amp do you have?

I would say that for most serious applications people use a single amplifier per channel and run each driver on a seprate amp channel.  The amp is much happier then and less loss across the cable.
Title: Re: Eminence Lab 12C High Power 12" Subwoofer Speaker Driver 4 Ohm
Post by: Jeff Bailie on April 22, 2013, 11:18:32 pm
The Danley DBH218 (and all other larger Danley subs) have a locking impedance switch on the rear panel.  It allows you to choose how you want to run the sub in YOUR application.

In the case of the DBH218-it is either a single 2 ohm load or 2x4 ohm loads.

Which ones is best for you?  It depends.  What is the music style (HUGE differences there)?  How long are the cable runs?  What type of amp do you have?

I would say that for most serious applications people use a single amplifier per channel and run each driver on a seprate amp channel.  The amp is much happier then and less loss across the cable.

Yes, I understand this...  Art was saying that the Lab12C Driver was a bad idea for Labhorns due to the low impedance when run in parallel.   Do you experience the same issue when you run the DBH218 really hard in 2 ohm mode?   

Just so everyone knows, I am not trying to squeeze more DB out of my Labs.  I am just curious. 
Title: Re: Eminence Lab 12C High Power 12" Subwoofer Speaker Driver 4 Ohm
Post by: Jeff Bailie on April 22, 2013, 11:30:27 pm
The Danley DBH218 (and all other larger Danley subs) have a locking impedance switch on the rear panel.  It allows you to choose how you want to run the sub in YOUR application.

In the case of the DBH218-it is either a single 2 ohm load or 2x4 ohm loads.

Which ones is best for you?  It depends.  What is the music style (HUGE differences there)?  How long are the cable runs?  What type of amp do you have?

I would say that for most serious applications people use a single amplifier per channel and run each driver on a seprate amp channel.  The amp is much happier then and less loss across the cable.

Hey Ivan,  How would you run 12 Labhorns?  I am currently using 6 PLX3602.  I am not unhappy with them. however,  I would like to move to more quality amps in preparation for more powerful sub cabinets in the future. I would like to save space and weight of course.  I am considering Lab Gruppen PLM stuff because of all the fun new toys on board. 

Title: Re: Eminence Lab 12C High Power 12" Subwoofer Speaker Driver 4 Ohm
Post by: Ivan Beaver on April 23, 2013, 07:25:21 am
Hey Ivan,  How would you run 12 Labhorns?  I am currently using 6 PLX3602.  I am not unhappy with them. however,  I would like to move to more quality amps in preparation for more powerful sub cabinets in the future. I would like to save space and weight of course.  I am considering Lab Gruppen PLM stuff because of all the fun new toys on board.
If you are wanting to move to larger amps-then go ahead.  Having headroom is never a bad thing-just set your limiters correctly.

"How to run" is s wide open question.  There are many different ways-and the answers will depend on a lot of variables-such as cable distance-current available for the amps-type of music material etc.

If you want "THE BEST" way-then I would say to run each driver on its own amp channel that is rated around 3000 watts @ 4 ohms.  So that would be a dozen amps for 12 cabinets.  The amps will be nice an happy-you should not be tripping breakers-assuming each amp is on its own breaker and you would have plenty of headroom for peaks.

And also have the possibility of totally tearing up all the drivers if things get out of control.  Headroom and damage potential go hand in hand.  The more of one you have-you get more of the other for free.

If you say that is to expensive-then now you have started to compromise-and you have to determine which is the best compromise for your situation and what you do.

Title: Re: Eminence Lab 12C High Power 12" Subwoofer Speaker Driver 4 Ohm
Post by: Jeff Bailie on April 23, 2013, 04:22:20 pm
If you are wanting to move to larger amps-then go ahead.  Having headroom is never a bad thing-just set your limiters correctly.

"How to run" is s wide open question.  There are many different ways-and the answers will depend on a lot of variables-such as cable distance-current available for the amps-type of music material etc.

If you want "THE BEST" way-then I would say to run each driver on its own amp channel that is rated around 3000 watts @ 4 ohms.  So that would be a dozen amps for 12 cabinets.  The amps will be nice an happy-you should not be tripping breakers-assuming each amp is on its own breaker and you would have plenty of headroom for peaks.

And also have the possibility of totally tearing up all the drivers if things get out of control.  Headroom and damage potential go hand in hand.  The more of one you have-you get more of the other for free.

If you say that is to expensive-then now you have started to compromise-and you have to determine which is the best compromise for your situation and what you do.

ohh yes... That is what I'm talking about.

 I have been running the same system for a few years now. I have learned a lot about the dynamics of my particular system. I have decided to get into some new gear just to keep myself sharp.  I am very interested in Lake Processing.  I think it will give me a chance to more fully understand some of the finer ins and outs of signal flow.   I think with ISVPL and some of the other forms of limiting in the Lake system I should be able to get a good grasp of how to run a system with double or triple over rms without damaging drivers.

currently I am running my system limited 1 dB shy of clip on everything. All my amps are just powerful enough to draw rms. And everyone thinks its the best sound they have ever heard...  haha.  I know its not.  There is so much more for me to learn.  The kids in the crowd are just used to listening to the i inch tweeters in they're laptop computers.

thanks Ivan, your knowledge is always appreciated.
 
Title: Re: Eminence Lab 12C High Power 12" Subwoofer Speaker Driver 4 Ohm
Post by: Ivan Beaver on April 23, 2013, 06:24:35 pm
ohh yes... That is what I'm talking about.

 I have been running the same system for a few years now. I have learned a lot about the dynamics of my particular system. I have decided to get into some new gear just to keep myself sharp.  I am very interested in Lake Processing.  I think it will give me a chance to more fully understand some of the finer ins and outs of signal flow.   I think with ISVPL and some of the other forms of limiting in the Lake system I should be able to get a good grasp of how to run a system with double or triple over rms without damaging drivers.

currently I am running my system limited 1 dB shy of clip on everything. All my amps are just powerful enough to draw rms. And everyone thinks its the best sound they have ever heard...  haha.  I know its not.  There is so much more for me to learn.  The kids in the crowd are just used to listening to the i inch tweeters in they're laptop computers.

thanks Ivan, your knowledge is always appreciated.
If available-I prefer 3 types of limiters-peak (fast attack), "average" or continuous (1/2 of lowest freq attack) and powercompression (typically 1/4-1/2 half continuous power and SLOOOOOOW attack on the range of 3-4 seconds.
Title: Re: Eminence Lab 12C High Power 12" Subwoofer Speaker Driver 4 Ohm
Post by: Jeff Bailie on April 23, 2013, 08:38:11 pm
If available-I prefer 3 types of limiters-peak (fast attack), "average" or continuous (1/2 of lowest freq attack) and powercompression (typically 1/4-1/2 half continuous power and SLOOOOOOW attack on the range of 3-4 seconds.

Awesome... with all that being said, I plan to go with awesome new amps for my next system.   Say I were to buy 6 DBH218's or some other power hungry cabinets that can handle 7200 watts.  For high output dance music, or in the case of Burning Man where we run the system continuously for multiple days, how much power do you give something like that?

 I imagine the maximum dB output peaks much earlier than its peak power capacity.  How much over rms do we need to achieve the peaks at low hertz like 35? 

sorry, I am just rambling now...

Thanks again for all the info. 

Title: Re: Eminence Lab 12C High Power 12" Subwoofer Speaker Driver 4 Ohm
Post by: Ivan Beaver on April 23, 2013, 08:58:41 pm
Awesome... with all that being said, I plan to go with awesome new amps for my next system.   Say I were to buy 6 DBH218's or some other power hungry cabinets that can handle 7200 watts.  For high output dance music, or in the case of Burning Man where we run the system continuously for multiple days, how much power do you give something like that?

 I imagine the maximum dB output peaks much earlier than its peak power capacity.  How much over rms do we need to achieve the peaks at low hertz like 35? 

sorry, I am just rambling now...

Thanks again for all the info.
The DBH218 is NOT a "power hungry" cabinet.  That refers to a cabinet that requires a lot of power to get a decent output.  In this case it is very sensitive AND can handle a good bit of power-so the max output is very high.

If you are running any system for long periods of time-with low crest factor music-it is NOT a good idea to run high power-but rather to run LESS power-and keep the amps from clipping.  Long term heat can be a real issue.

Generally 1/2 or continuous is the most I would recommend.  For "normal" music, you can "overpower" them-because the heating is less due to the higher dynamic range.
Title: Re: Eminence Lab 12C High Power 12" Subwoofer Speaker Driver 4 Ohm
Post by: Jeff Bailie on April 23, 2013, 10:07:49 pm
The DBH218 is NOT a "power hungry" cabinet.  That refers to a cabinet that requires a lot of power to get a decent output.  In this case it is very sensitive AND can handle a good bit of power-so the max output is very high.

If you are running any system for long periods of time-with low crest factor music-it is NOT a good idea to run high power-but rather to run LESS power-and keep the amps from clipping.  Long term heat can be a real issue.

Generally 1/2 or continuous is the most I would recommend.  For "normal" music, you can "overpower" them-because the heating is less due to the higher dynamic range.

Ahh, true... with a sensitivity of 117 the DBH218 only needs a little power to make a lot of Bass.

I thank you for your time Ivan.
Title: Re: Eminence Lab 12C High Power 12" Subwoofer Speaker Driver 4 Ohm
Post by: Jeff Bailie on April 23, 2013, 10:19:21 pm
The DBH218 is NOT a "power hungry" cabinet.  That refers to a cabinet that requires a lot of power to get a decent output.  In this case it is very sensitive AND can handle a good bit of power-so the max output is very high.

If you are running any system for long periods of time-with low crest factor music-it is NOT a good idea to run high power-but rather to run LESS power-and keep the amps from clipping.  Long term heat can be a real issue.

Generally 1/2 or continuous is the most I would recommend.  For "normal" music, you can "overpower" them-because the heating is less due to the higher dynamic range.

I have another question rattling around in my head now. I think it deserves it's wn post maybe in a different location. But now that I have your attention I will just ask it here.

Q:  With some of the new limiter technologies such as Lakes ISVPL is it possible to program the amp to limit at a certain voltage in turn possibly limiting the total wattage available for a driver to draw?  (Example  -PLM20000q has 4 5000watt at 2 ohm channels. Is it possible to limit one of these channels down for use with a single 50watt rms compression driver).  I am using an exaggerated example really.. Just curious.

 I cannot understand voltage to driver relationships yet.  I have no idea what kind of voltage my Labhorns get. or any of the the rest of my speakers.   I am slowly unlocking these personal mysteries thanks to you guys here.  Another reason I want to delve into Lake.
Title: Re: Eminence Lab 12C High Power 12" Subwoofer Speaker Driver 4 Ohm
Post by: Ivan Beaver on April 24, 2013, 07:32:27 am
Ahh, true... with a sensitivity of 117 the DBH218 only needs a little power to make a lot of Bass.

I thank you for your time Ivan.
This is a clear case of not doing enough reading of the spec sheet.

It is VERY CLEAR on the spec sheet that the 117dB number is at 100hz.  The overall sensitivity is 112dB.  And that is with a 2.83V input into a 2 ohm load-which is 4 watts-assuming a constant 2 ohm load-which it is not-just like any loudspeaker.

But for the "simple number crowd"-then yes it is 117dB in the "bass region"

I prefer to think in terms of voltage-it is much better than wattage and gives a much clearer "picture".

Title: Re: Eminence Lab 12C High Power 12" Subwoofer Speaker Driver 4 Ohm
Post by: Ivan Beaver on April 24, 2013, 07:36:00 am
I have another question rattling around in my head now. I think it deserves it's wn post maybe in a different location. But now that I have your attention I will just ask it here.

Q:  With some of the new limiter technologies such as Lakes ISVPL is it possible to program the amp to limit at a certain voltage in turn possibly limiting the total wattage available for a driver to draw?  (Example  -PLM20000q has 4 5000watt at 2 ohm channels. Is it possible to limit one of these channels down for use with a single 50watt rms compression driver).  I am using an exaggerated example really.. Just curious.

 I cannot understand voltage to driver relationships yet.  I have no idea what kind of voltage my Labhorns get. or any of the the rest of my speakers.   I am slowly unlocking these personal mysteries thanks to you guys here.  Another reason I want to delve into Lake.
It is not a matter of "newer technology", you can "turn down" the max output of any amp with a limiter to anything you want it to be.

The driver does not "draw" any power-it only turns the waste into heat.  How much "waste" there is, depends on the input voltage going to the driver and its impedance at a particular freq.
Title: Re: Eminence Lab 12C High Power 12" Subwoofer Speaker Driver 4 Ohm
Post by: Jeff Bailie on April 24, 2013, 03:55:30 pm
It is not a matter of "newer technology", you can "turn down" the max output of any amp with a limiter to anything you want it to be.

The driver does not "draw" any power-it only turns the waste into heat.  How much "waste" there is, depends on the input voltage going to the driver and its impedance at a particular freq.

haha awesome.  I re read that last post of mine a few times since I last wrote it. I wanted to delete it and re word it knowing that you would jump on me for my incorrect and miss worded definitions.  I need to spend more time properly planing my posts on here.  It is hard to ask questions when I don't know what I am talking about.  Like I said. Much of the inner workings of my own sound system are a mystery to me.  I want to know more.

I realize that no special technology is going to replace the knowledge and experience of an engineer like some of you professionals here on pro sound web.