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Author Topic: Bridging Subwoofers?  (Read 17319 times)

Justin Smith

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Re: Bridging Subwoofers?
« Reply #20 on: April 02, 2014, 11:37:52 pm »

Take the bass & most drums out of the PA.
You do not have "enough rig for the gig" to improve the bass & guitars and cymbals and snare. You need significant subs to deal with rock kick and bass.


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Not sure if you are using a metaphor or not, but i'm not using this system for a rock band and the equipment that i have is perfectly good for what I need it for right now.
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duane massey

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Re: Bridging Subwoofers?
« Reply #21 on: April 03, 2014, 12:47:31 am »

Simple approach: hook up the system as Bob suggests. If it is loud enough for your needs, be happy. If it is not, either upgrade to (1) bigger amp (2) better subs (3) both OR try running the amp bridged into a 4ohm load. The challenge with this is that by the time you see the clip light you may be already doing in your subs. Also, note that the distortion at the claimed output bridged into a 4ohm is 1%.
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Duane Massey
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Jeff Bankston

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Re: Bridging Subwoofers?
« Reply #22 on: April 03, 2014, 03:49:27 am »

each sub is only rated for 400 watts continuous, 1600 watt peak.
are you sure it says 400 watts Continous , 1600 watts Peak ? that doesnt make any sense. The very best driver made are only rated twice as much power for Continous/RMS/AES vs Peak. "If" you woofer is rated for 400 watts Continous than Peak/Program Power would be 800 watts not 1600 watts.
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Bob Leonard

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Re: Bridging Subwoofers?
« Reply #23 on: April 03, 2014, 08:22:38 am »

400 long term, 800 program peak, 1600 instantaneous peak. The question is always for how long and I think JBL is the only company posting that spec.
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Scott Olewiler

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Re: Bridging Subwoofers?
« Reply #24 on: April 03, 2014, 12:26:13 pm »

400 long term, 800 program peak, 1600 instantaneous peak. The question is always for how long and I think JBL is the only company posting that spec.

Actually quite a few manufacturers post all 3, including Yorkville to name one, and peak is generally 4x continuous, program 2xs. 
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Tim McCulloch

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Re: Bridging Subwoofers?
« Reply #25 on: April 03, 2014, 12:50:36 pm »

The Crown website advises power amp owners to choose amps that are rated at 2-4 times the continuous power rating of the speaker load. That is what I go by.

That means a speaker rated at 400W RMS/800W Program/1,600W Peak should have 800 - 1,600 watts of power available to each cabinet.

Based on this formula, I would recommend powering two speakers rated 350W RMS with a single bridged power amp that puts out between 1,600 and 3,200 watts peak power. This will give you 2-4 times the continuous power rating of the speaker which is within the Crown website specs.

Having more amplifier headroom vs. less will keep you from clipping your amps, which is the most-common cause of driver damage. When you drive an amplifier too hard it causes distortion and clipping, whereas a properly power speaker system will avoid distortion and clipping.

Sure, you can still blow up your speakers if you push them too hard even with plenty of amp headroom - but the chance of blowing up your drivers actually decreases with more power vs. underpowering. Treat it like a Corvette... you've got all the power you need, but you don't have to use it all! I'd rather hear and feel a solid kick drum in the subwoofers than a bunch of distortion and mud due to amp clipping in an underpowered sub.

http://www.crownaudio.com/how_much_power.htm

Hope this helps! I had to learn the hard way by toasting two subwoofer baskets due to underpowering/clipping them. Running a speaker with an amp that only puts out the continuous wattage rating of the speaker (or less) creates a virtual guarantee that you will clip your amps when trying to make the speaker loud enough.

No, the text in bold is pure and unmitigated bullshit.
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Justin Smith

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Re: Bridging Subwoofers?
« Reply #26 on: April 09, 2014, 12:44:57 pm »

OK, let's be more accurate. My remarks have to do with you having a working, good sounding, safe system utilizing the hardware you own.

If your goal is to upgrade then the approach that I have preached for better than 40 years concerning power to the cabinets is two (2) times the long term power rating. This "rule of thumb" is what the industry practices and preaches. This is what JBL, EV, and most reputable manufacturers will recommend.

There are two ways to destroy your cabinets. The first is to over power the cabinets, and if you're going to use an amplifier rated 2,3,4 times the long term power rating you need to understand your speakers capabilities and insure the additional power is used as intended. Not to drive the cabinets another 3db louder, but to allow for additional power to meet the instantaneous short term needs of the program material.

If you need more output than what your cabinets will handle safely then you need to upgrade, end of subject.

The second way to destroy your cabinets and probably your amplifiers is to drive them into hard clip. clipping and amplifier can produce a minimum of two times the rated output voltages. I'm not going into detail on the subject because it's been covered here a thousand times. Just be aware that the little red light is there for a reason, and that reason is to tell you bad things are about to happen.

In the end the choice is yours. Either live with a few db lass output, or push your cabinets to their limit and trust you know enough about controlling sound to keep them from being destroyed.

I followed Corey's post that has the picture in it. I changed the dip switches to the red marked positions in his picture. This is also following you advice. Now, I will need to change my speakon cable on my amp side from 1,2 back to 1,1 since I am not bridging anymore, correct?
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Brian Jojade

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Re: Bridging Subwoofers?
« Reply #27 on: April 09, 2014, 05:46:13 pm »

The Crown website advises power amp owners to choose amps that are rated at 2-4 times the continuous power rating of the speaker load. That is what I go by.

That means a speaker rated at 400W RMS/800W Program/1,600W Peak should have 800 - 1,600 watts of power available to each cabinet.

Crown recommends those power ratings because for them, selling a bigger amp is more money.  However, when you size your amp above the continuous power rating of the speaker, then the operator has to take responsibility of using the power correctly.  An amp with 4X the continuous power rating can EASILY blow up a driver.  Play long sustained bass notes at full power and that speaker isn't going to last very long!!

Match an amp's output to the RMS rating of the speaker, and you're going to have to try really hard to damage the speaker.  Yes, it's still possible, but it's probably going to sound like total crap before anything goes wrong.  If you can't figure out to turn it down based on the sound, then you deserve to be replacing drivers in that case.

Now, matching RMS to Power means you can't squeeze the last couple of dB out of a cabinet.  But to me, that's like taking the effort to get the extra little bit out of a toothpaste tube.  When the effort to get toothpaste out gets to a certain point, just get another tube.  If you can't get the sound out of one sub at RMS, add another sub.  That'll do the same thing with no risk as doubling the power to the sub and chancing a burnout.
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Brian Jojade

Jeff Bankston

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Re: Bridging Subwoofers?
« Reply #28 on: April 09, 2014, 06:24:43 pm »

Ciare , FaitalPro , Beyma , only post AES and PROGRAM power in their specs. i asked the manufacturers because i build my own speakers and wanted to know about "Instantanios power". the reply i got from FaitalPro and Ciare was > never exceede Program Power and they only use the 2 ratings not 3. for those that never heard of Ciare or FaitalPro they are what Meyer , Clair , L Acoustics and all the other big companies use in their "high dollar" best of the best boxes. i would not go past the AES/RMS raiting. most decent drivers will handle 2 times the AES/RMS raiting. > 100/200 watts.

also: i use one qsc amp in bridged mono rated 1700 watts RMS at 4ohms to power one FaitalPro 4 ohm 18" woofer rated 1600 watts RMS. never had a problem.

i also use one qsc amp in bridged mono rated 1100 watts RMS at 4ohms to power two(2) Ciare 8ohm 12" woofers each woofer rated 500 watts RMS wired parallel for a 4ohm load rated at 1000 watts RMS for the pair and never had a problem.

i never had a problem with bridged amps and the sound is awsome. but of course i have Verizon , can you hear me now ? 
« Last Edit: April 09, 2014, 06:45:04 pm by Jeff Harrell »
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Jay Barracato

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Re: Bridging Subwoofers?
« Reply #29 on: April 09, 2014, 07:21:03 pm »


Now, matching RMS to Power means you can't squeeze the last couple of dB out of a cabinet.  But to me, that's like taking the effort to get the extra little bit out of a toothpaste tube.  When the effort to get toothpaste out gets to a certain point, just get another tube.  If you can't get the sound out of one sub at RMS, add another sub. 

Yep, yep, yep

Or "I can only afford a 4 cylinder ford ranger, so I plan on towing for extended periods with the engine turning 6500 rpm. How can I get more passing power?"

Getting a bigger engine ain't enough, get brakes, suspension, drive train... you mean a bigger truck.

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« Last Edit: April 09, 2014, 07:24:18 pm by Jay Barracato »
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Jay Barracato

ProSoundWeb Community

Re: Bridging Subwoofers?
« Reply #29 on: April 09, 2014, 07:21:03 pm »


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