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Buck PomerantzI've been tinkering with electronics ever since I was a kid - starting with taking apart and putting back together televisions and radios. I always got them back together again and working. I took courses in radio and electronics as a teenager, and became a ham radio operator. I worked in my high school's stage crew, running sound, lights, and a movie projector. After college, I joined a rock 'n roll band as the soundman and learned how to lug around and operate the gear that helps make music sound good and loud.Working in a music store in Austin, Texas, I spent a few years manufacturing, installing, repairing, and operating sound systems.

Our customers were recording studios, nightclubs, and touring bands. Eventually I moved back to Charlottesville, Virginia and opened a small demo recording studio. In 2006, I finally came to my senses and got this job at Crutchfield. They actually pay me to ramble on, rant, and explain the things I love about music, electronics, and getting good sound.Given my background, they put me to work writing about some of the most complex electronic products Crutchfield sells: car amplifiers, digital signal processors, wiring, professional sound mixers, and PA systems. In a NutshellA subwoofer has impedance (measured in ohms) which represents the 'load' an amplifier will sense on its output.

Adding a load balancer to your server environment is a great way to increase reliability and performance. The first tutorial in this series will introduce you to load balancing concepts and terminology, followed by two tutorials that will teach you how to use HAProxy to implement layer 4 or layer 7 load balancing in your own WordPress environment. High Voltage: Any voltage exceeding 1000 V rms or 1000 V dc with current. Capability exceeding 2 mA ac or mA dc, or for an impulse voltage generator having 3. A stored energy in excess of 10 mJ. These current and energy levels are slightly below. The startle response threshold (IEEE Trans.

An amplifier will put out different amounts of power (watts RMS) based on the impedance load it 'sees.' Getting the right sub for an amp, or the right amp for a sub, is like solving a puzzle where the amplifier's capabilities (X watts RMS into Y ohms) needs to match the subwoofer's specifications (Y ohms and can handle X watts RMS). Your goal is to get those two variables to match for both the amplifier and the subwoofer.

Full StoryThe secret to great bass is making sure your subwoofers and amp are evenly matched and will properly work together. And this article will help you figure out how to do just that — match amplifiers and subwoofers.

We cover the important basics of power-matching, impedance, and planning for the number of subs you want, and we approach the situation from both sides of the system:.: You have the subs, which amp should you get?.: You have the amp, which subs should you get?Start with either part you want, but they're both worth a read.Part AYou have the subs, which amp should you get?The subs need to be the sameMultiple subs wired together must be the same coil type and impedance. If they’re not, the power won’t divide evenly between them, and some subs would probably be over-powered while others get under-powered. If you want to run different types of subs in a system, each type needs to have its own separate amp. Step 1: How much power? Find out the “watts RMS” rating of the subThen, multiply the number of subs you have by the RMS rating of each, to get their total RMS rating. You want to make sure the amp you choose is capable of supplying from 75% to 150% of the sub system’s total RMS rating.

Step 2: What impedance? Example:You have two 8' subwoofers and you want the right amp for them.They are DVC 4-ohm subs rated at 350 watts RMS each.Two 350 watts RMS subs together need a total of 700 watts RMS, but an amp putting out from 525 to 1050 watts RMS will do.

Subwoofer amplifier Part BYou have the amp, which subs should you get? Step 1: What can the amp do?

Find the RMS ratings of the amp at different loadsFind the amp’s power, expressed in “watts RMS”, at 4 ohms, at 2 ohms, and, if it can, at 1 ohm. Pick the power you’d like to achieve. The load impedance (ohms) of that rating will be what you want your subs’ total impedance to be. Step 2: How many subs do you want?Divide the power you picked in Step 1 by the number of subs you want. This number is the target RMS rating for each of the subs you’ll choose. Divide that target number by 1.5.

Example:You have a amplifier and you want it to drive two subwoofersThe amp is capable of 350 watts RMS x 1 at 4 ohms and 500 watts RMS x 1 at 2 ohms.Let’s say you choose to maximize the amp’s potential and want the system to put out 500 watts RMS. This means your subs have to be wired to form a total impedance of 2 ohms.Two subs on a 500 watts RMS amp will want about 250 watts RMS each.250 divided by 1.5 is 167; 250 divided by 0.75 is 333.

So you’ll look for subs each rated between 167 and 333 watts RMS.Using the chart in Step 3, for two subwoofers, a final 2-ohm load can be achieved with either two SVC 4-ohm subs or two DVC 2-ohm subs.So, you’ll look for two subs that are either SVC 4-ohms or DVC 2-ohms, rated between 167 and 333 watts RMS each:. 2 SVC 4-ohms, 167-333 watts RMS, or. 2 DVC 2-ohms, 167-333 watts RMSAmong Crutchfield’s selection of subwoofers you’ll find:. — SVC 4-ohm, 250 watts RMS. — SVC 4-ohm, 250 watts RMS. — SVC 4-ohm, 300 watts RMS.

— SVC 4-ohm, 300 watts RMS. — DVC 2-ohms, 250 watts RMS. Shane from Lake Jackson Posted on 6/16/2019I have 2 JL Audio 12TW3-D8 wired for a 2 Ohm Final Impedance @ 800W RMS in a JL Audio Stealthbox. I have a Rockford Fosgate Prime 1200.1D that does 800W RMS @ 2 Ohm ( though it's closer to 880W on a dyno). Is this enough wattage for this setup or should I look for something larger? The bass sounds amazing in my 2010 GMC Sierra 1500 Crew Cab but outside the vehicle the bass doesn't seem that loud at all. So just wondering if I need to step up the size of the amp or am I just being picky?

Travis from Beaumont tx Posted on 6/5/2019I have two 15 inch SHOK industries subs that are 4ohms a piece. I never heard of this brand but with a little research lol I think they're pretty powerful@ 500 watts rms, not sure if that's true but I have an ARC AUDIO FD2200 AMP pushing them, and they hit! But my amp gets hot sort of quick which prevents me from turning the gain up high. I have the speakers wired in parallel to one channel.

Curious.is this the right set up with what I have. I don't understand why the speakers cut out after a like 15 mins of playing. Devan from Mesa, Arizona Posted on 5/17/2019I just purchased a truck 2 days ago with a Pyle power pla4478 4 Ch 4000 Watts Bridgeable Mosfet Amplifier. It has two Kicker CompD 8 Inch 4 Ohm Subwoofers in a box under the seat, it was utilizing. I noticed a weird smell when I purchased the truck, but got side tracked with the excitement and additional features I was shown.

Just today ((within 48 hours, and not messing with any of the radio settings)) the sub suddenly went silent. Later in the day I picked up a co worker who has done some light car audio and as soon as he got in my truck he said he could smell a speaker blown somewhere. We investigated and found only one to have the smell and some resistance when we gently pushed on it. When I got home I busted out my finances old ken wood sub just to see if it would power on.

My friend says the owner of the truck, had way to much power for those little guys. I was wondering if this were accurate, and I'd also like to ask you Buck, what speakers would work/you'd recommend with this 4 Ch 4000 Watt Pyle. Thanks for doing this for all of us! Ray Donovan from Las Vegas Posted on 1/29/2019Hey Buck,Thanks for the Great article. I'm curious though, in 'Part A - Example', you are multiplying the RMS value by 0.75 & 1.5 to get the minimum and maximum RMS values.700 watts RMS75%: 525150%: 1050But in 'Part B - Example' you are dividing the RMS value by 0.75 & 1.5 to get the minimum and maximum RMS values.250 watts RMS75%: 167150%: 333The correct way to find the percent of a number would be to 'multiply' the RMS value by the Percentage. Is there some specific reason why you chose to 'divide' in Part B rather than 'multiply'?

Ray Gomez from Lubbock Posted on I have been doing as much research as I can about subs and amps. I have 2 Audiopipe TXXBD412, 4 ohm DVC. I am going to be wiring them parallel to 1 ohm. The total watt per sub is 2200 W and 1100W RMS.

According to what I learned from your article, I will need an amp that can produce a total of 1650 rms (75% for both subs) to 3300rms (150% for both subs). I was debating on getting the Audiopipe APMI-2000 but after doing the math I don't fell it'll be powerful enough to push them. Any advice or recommendations? From Manchester, NH - USA Posted on 4/12/2018I guess I am making this comment/question to pre-visualize what I will be encountering when I get my new subwoofers installed on the 21st of this month. I have purchased two JL Audio 10Tw3-4's each with an RMS rating of between up to 400w and are both 4 ohm dual V coils. The 'optimal' green zone on JL's website is showing the 250watt area.

And anything over 500watt is in the black zone symbolizing being not recommended. I own two Alpine MRV 500/1 amps. One for each JL sub.To simplify though let's pretend at this point I have just one sub and one amp.The amp will be providing 500w RMS at 2 ohm.OR. 300w RMS at 4 ohm. The JL website 'danger scale' is seemingly going against the overall agreement that having more power.available. is better for subs than under powered. So would I be better giving the sub its native 4 ohm parameter and output at a 300w RMS level (which would be 100w under the subs top spec of a 400w RMS rating.) or am I going to be taking a risk dropping to 2 ohm and throwing the full 500w RMS at it?

(which would be 100w OVER the subs top spec of a 400w RMS rating.)side note of interest: Nowadays I go for an all-around full concert sound versus my 'Basshead' days of simply trying to anger people hundreds of feet away with constant low end, so what matters to me now is giving my system the BEST arrangements for the best and safest dynamics.Thanks for providing any advice you have. Buck Pomerantz from Crutchfield Posted on Tony, A subwoofer acts like a passive inductive load with its impedance value measured in ohms. An amplifier will react differently to different loads - an amp that can put out 125 watts RMS through a 4-ohm load will often be able to put out twice that, 250 watts RMS, through a 2-ohm load. It's like lifting weights: your arms (the amplifier) don't change when you change weights (the load/ohms), but your effort and work output (the power/watts) do.

Tony from Bowling Green Posted on Hello, I'm looking at purchasing (1) of these Polk Audio MM842DVC 8'Peak Power Handling - 900 Watts. RMS Power Handling - 300 Watts. Nominal Impedance - 4 Ohms. I may add a second one at a later date. This is the amp I'm thinking about getting to power the 8'sub with and would like to know if this would be an ok, setup.

Polk Audio PA D2000.2 class D 2 Channel ratted at 125 watts RMS x 2 at 4 ohms or 250 watts RMS x 2 at 2 ohms or 500 watts RMS x 1 in bridged mode (4-ohm stable in bridged mode) would this setup be ok? Corey Fontenot from Bunkie, Louisiana Posted on 8/20/2017Hi, I am curious to which Amplifier to buy for my TWO new Pioneer TS-W3003D4 12' 2 DVC 4 Ohm @ 2 O or 8 O Impedance. Each Subwoofer is 2000 Watts Max/600 Watts RMS EACH(All together I have 1200 Watts RMS power). I don't know much about Amplifiers but, I get an idea on what kind of amp to run off of the article.

I need your approval. From the setup of subs I run, I have two amps I have in mind. Which one you prefer that will work the best? The Rockville dB13 3000 Watt/1500 Watt RMS Mono D 2 Ohm, OR, the Boss Phantom.

PT 2600 Watt class A B 4 Channel 2 or 4O 1300 Watt RMS? Also, if neither are suitable, can you tell me what kind of other amp is better?

Means and helps a lot if I get feed back. Please and thanks.,Corey F.

Sikholiwe from Cape Town, Posted on 7/26/2017I had a sound system installed in my car with the following sound system parts:- AMP rated at 6900 Watts RMS, I don't know the impendence.- Two Subs each rated at 2000 Watts RMS, I don't know the impendence.Four days after installation the subs blew up. Using your guidelines for matching Subs and AMP, my calculation results reveal that an AMP rated between 3000 to 6000 Watts RMS would have been suitable for the 2000 Watts RMS Subs which I have. Similarly, Subs rated between 2300 to 4600 Watts RMS would have been suitable for the 6900 Watts RMS AMP that I have.I would like to know if the mismatch between the AMP and the Subs could have been the reasons for the Subs to blow up.Thanks. Buck Pomerantz from Crutchfield Posted on 6/15/2017Thomason, I don't know anything about that amplifier, or even what audio gear is available in your country. It appears that two of your subs are DVC 2-ohm models and the other four are DVC 4-ohms.

You should never connect subs of different impedances together to the same amplifier - the lower impedance subs will get more power than the higher impedance subs, resulting in unbalanced sound levels and potentially blown subs. Get two amplifiers for your two different types of subs.

Adrian from Baltimore,Md Posted on 5/27/2017Hello i have two 08ds12l72 subs currently running it with a Kicker zxS1500.1 also have a zx1000.1 i know these subs are 750rms 1500 max,my question is that per sub?in that case i have 3000 watt max so i should be able to run a zx2500.1.i have fully upgraded my electrical with all 0/1 gauge wiring awesome grounds and a HO ALT @ 340 amps and a Northstar agm 34.And sadly still not happy with the sound.planning on getting a kicker eq or mabye the epicenter.just want more:(should i put the zx1000 and see how they sound,or buy a better box?. Buck Pomerantz from Crutchfield Posted on 4/27/2017Michael, Your mono, 1-channel amplifier has 2 speaker output terminals that are wired together inside the amp. The second speaker output terminal is there for convenience and if you hook a sub to each terminal it would result in the two subs being wired in parallel, cutting the total impedance in half. If you wire a 2-ohm sub to each terminal, that amp would go into protect mode to prevent burning up. I suggest getting a second amp to drive your second sub. Michael Sousa from CA Posted on 4/26/2017I Have a MTX thunder 1000xd amp its a mono block and has 2 sets of +,- terminals.

Specs say RMS Power Rating:4 ohms: 500 watts x 1 chan.2 ohms: 1000 watts x 1 chan.I currently have a DVC 1ohm Kicker 12'comprt that is wired at 2ohms plugged into the amp using The + on one set of terminals and the negative on the other. Slightly over powered i know. Id like to add another sub using the same amp. My question is if I get another identical sub and connect them independently one on each terminal at 2ohms is that what the separate terminals are for on this monoblock amp?

Can I even ad another sub while retaining my current sub? Looking for peak performance don't want to have power that's not being utilized.Thanks!.

Buck Pomerantz from Crutchfield Posted on 4/12/2017Nikki, A power supply designed for a camera or lighting system will not work with those amplifiers, it's way too small. If you are determined to use that car audio gear in a home system, you'll need a power supply capable of putting out DC12V 92A 1105W. If you're interested, here's the math: For the 4-channel amp to put out its full 60 watts RMS per channel, 240 total at 50% Class AB efficiency will require a 480 watts RMS supply. For the mono amp to achieve its 500 watts RMS output using 80% efficient Class D technology will require 625 watts RMS. 480 + 625 = 1105. 1105 watts divided by 12 volts equals 92 amperes.

Buck Pomerantz from Crutchfield Posted on 4/11/2017Nikki, Not knowing exactly what amplifier or subwoofer you have make it impossible to give advice on how to power them. If you want a question answered about a system, you must identify the gear by model numbers as well as brand names. I can tell you that a 12-volt 20-amp power supply can support a 120 watts RMS Class AB amplifier or a 190 watts RMS Class D amplifier. If you want to add massive bass to your home system and a home theater subwoofer isn't loud enough for you, I suggest looking at a professional PA subwoofer. You can probably check one out at your local music store. Todd from Ada Posted on 3/3/2017I am thinking of purchasing this BOSS AUDIO R2400D Riot 2400-Watt Monoblock, Class D 1 to 8 Ohm Stable Monoblock Amplifier with Remote Subwoofer Level Control, to power two KICKER S10L74 10' 1200W/600W PEAK/RMS 4-Ohm Car Audio Subwoofer L7's.

The amplifier says 2400 W MAX Power, 1 Channel 1800 W X 1 RMS @ 1 ohm 900 W X 1 RMS @ 2 ohm 450 W X 1 RMS @ 4 ohm. If I'm right this is 150% of the RMS for this pair of subs @ 1 ohm. Am I right and would this be a good amp for my subs? Also should I purchase a capacitor with this set up?. Tony Shelton from Charleston,SC Posted on 8/23/2016Hi Sir, I have two 12inch Kenwood 4ohm 400rms Subwoofers, model 'KFC W-3013PS' and i am looking at buying a Rockville RXD T-2 class D 2 channel amp thats CEA rated (2 times 400 watts@ 4 ohms),///////,(2 times 600 watts @ 2ohms),///,(1 times 1200 watts @ 4ohm bridged mono) I am 59 and trying to get this done for my Grandson Graduation gift, Will you Please help me to know which way to hook up the Subwoofers.or should i look at a different amp?It was so much easyer back in the 80s and early 90's when i was a younger man. Thank You Very Much For Your Help Sir!. Josh from San Antonio Posted on 7/9/2016Hey Buck, thanks for helping me out but I have one more question.

Someone said on another thread, 'IF you connected a sub running at 8 ohms, to an amp running at 4 or 2, the resistance would be great and the amp would run hot. When this happens it over heats and eventually shuts down resulting in returns. If the amp is running at 4 ohms and the sub is running at 1 or 2 then the sub gets pushed harder to compensate and the voice coils will generate more heat and lock up.' If I use the two 400watt rms 4ohm subs with a 1ohm amp, will I be pushing the amp harder or do the subs get turned INTO a 1ohm load, by wiring them how you said, and then become equal when connected with a 1ohm amp? I just don't want to burn/blow anything up since there is a lot of money involved. Buck Pomerantz from Crutchfield Posted on 7/7/2016Josh, You're correct as to how much power you'll need for that pair of subs.

The other part of the equation is at what impedance does this power need to be delivered through? Two DVC 4-ohm subs can only get wired together to form a 16-ohm load, a, or a. So, you'd get an amplifier that can output 600 to 1200 watts RMS at one ohm or at four ohms. It could feed those subs a total of 800 watts RMS, 400 each, which is exactly their top RMS rating. Randy Bagby from Kokomo Posted on 7/6/2016You would think a company the size of crutchfield would employ engineers that know how this works and give proper answers. Quite frankly, I have lost respect for your company. The amount of power a subwoofer cab handle is dictated by excursion demands imposed by the enclosure.

The only way to know is to middle it using the T/S PARAMETERS and a good modeling program. In reality, subwoofer wattage ratings are the most worthless spec the company gives you. Who cares how much heat it can handle, we listen to music, which is dynamic. A driver in a small sealed box might take 3X's it's rated power to achieve x-max whereas the same in an IB alignment may pass it's mechanical limits on a third of what the company recommends. All you're doing is guessing at what might work, but have absolutely no way of knowing without knowing what enclosure the driver is going in. Please research this subject do you can inform your potential customers the correct way to pick an amp.

Buck Pomerantz from Crutchfield Posted on 6/30/2016Felix, Not knowing exactly which subwoofer you have makes it impossible to give advice on how to wire it. Kicker makes 10-inch CompRT subs in a DVC 1-ohm and a DVC 2-ohm model. If you want a question answered about your system, you must identify your equipment by model numbers as well as brand names.

As for amp gain, it is not for achieving maximum output. It is to match the input sensitivity of the amp to a receiver's output. Check out for help setting amp gain. Chris Norris from Titusville Posted on 3/25/2016This is the best site I've seen by far your great. I don't know a lot about this stuff an I see u give people diagrams with your answer.

I have a amp an sub in my car already but I want to replace it I have the sub just need the amp. I have one pioneer TS-W3003D4 sub it's a dual 4 ohm 600w rms dvc. I only need a amp for this one sub an would like to safely get the most out of it. Could you give me a few amps that would go great with this sub an fall between $150 to 250 give or take. Thanks for any info an the time u take to help others. Buck Pomerantz from Crutchfield Posted on 3/11/2016Chris, Those subwoofers are SVC (single voice coil) 4-ohm subs and two of them can only get wired together as an 8-ohm or a.

That mono, 1-channel amplifier has two sets of speaker output terminals, wired together inside the amp, for convenience, and if you hook a speaker to each terminal it would result in the two speakers being wired in parallel, cutting the total impedance in half. For your set-up, that's exactly what you can do: Wire a 4-ohm sub to each terminal, and the amp sees 2 ohms as its total load. It's electrically the same as in the diagram in the link. Chris from Detroit Posted on 3/11/2016Hello, and firstly let me thank you for the wealth of information your site, and this thread in particular have provided me. I am looking to purchase 2 of the pioneer shallow mount 10' woofers (TS-SW2502S4) rated 300w/RMS (1200max) @ 4ohms.

I intend to run them with a pioneer GM-D8601 rated 300w@4ohm, 500w@2ohm, or 800w@1ohm (all RMS). My question is; what would be the proper way to wire this amp for 1ohm allowing 400w RMS to each woofer, given that this amp has outs for 2 speakers already (+.+-) not simply one set of outs (+-).

Or would it be best to simply wire each woofer to each output, and would that essentially be running each at 2ohm (250w each speaker)? The two sets of outputs has me confused a bit I suppose. Thanks again for your help!. Buck Pomerantz from Crutchfield Posted on 2/1/2016Randy, If we were to include in the article the information you discuss, 99% of our customers would not understand it, and so the article wouldn't help them very much with matching subs and amps. The subject's complicated enough. One thought they might walk away with would be your statement that: 'As long as you're not exceeding the mechanical limits of the driver you can basically give it as much power as you want.'

Only understanding the second part of that sentence, most people would blame their blown drivers on bad advice, and want warranty replacements or repairs. Reputable subwoofer manufacturers not only rate each of their products with a specific and useful RMS power rating but also state what kind of enclosures it will work in. If someone goes ahead and installs a sub in an infinite baffle (IB) arrangement that it wasn't designed for and blows it giving it its 'rated power,' they themselves would be responsible for the mis-application and damage, and wouldn't receive any warranty consideration. A sub designed to work in free-air or IB setups will be guaranteed to safely work at its rated RMS level. Randy Bagby from kokomo Posted on 1/30/2016I read through your 'how to match subs to an amp' and can't believe a company the size of yours with the resources you have, have it so wrong.

Wattage ratings on subwoofers are virtually meaningless. How much power a sub will handle and perform with is solely dictated by the excursion demands imposed by the enclosure. As long as you're not exceeding the mechanical limits of the driver you can basically give it as much power as you want. The more headroom the better.

We listen to music, which is dynamic, so your sub will never see maximum power for more than split seconds. The only way to know how much power you need is to model the driver into an enclosure using the T/S PARAMETERS, but no mention of those whatsoever. Anything else is just a guess.

Maybe an educated guess, but proper modeling takes 100% of the guesswork out of the equation. It's not hard, but it's the CORRECT way you should be educating people. Going by your recommendations my pair of 8'subs rated at 130w each should be on an amp of about 400w, but I know that in the enclosure they're in exactly what frequency they will exceed x-max and the db level that will occur, and they will handle just over 1000w. But in an IB configuration they will exceed it with less than rated power. What you're teaching will generally work, but why not teach people the CORRECT way to do things from the beginning.

Matt from Ohio Posted on 11/9/2015So if my math serves me correctly I should be able to pair aa single Pioneer TS-W3003D4 wired at 2-ohms (600 continuous) with a Pioneer GM-D9601 which is rated at 800 x 1 @ 2 ohms. Or is that amp to powerful for that single sub?Also if that amp is indeed to powerful would the GM-D8601 be a better fit with a 500 x 1 @ 2 ohm output?Trying to plan ahead if I ever decide to get a second sub so I would really prefer the GM-D9601 for the versatility to add to the system if decide to do so.Thanks. Drew2849 Posted on I just purchased a HO-110-w6v3 subwoofer/enclosure from Crutchfield. I've tried doing a lot of research for powering the sub which handles 600W RMS at 2 ohms. I already owned a JBL GTO-751EZ amplifier which puts out 750W RMS at 2 ohms. I know this article says it would be safe to power the sub with that amp because of the 75%-150% range, but I really don't want to damage the sub and I'm nervous about setting the gain properly.

My buddy owns a SMD-DD1 distortion detector that I could use to set the gain of the amp but wouldn't that put maximum power (without distortion) to the subwoofer? Should I use Ohm's Law instead, to put the proper voltage to the speaker from the amplifier so it is only getting 600W?.

Leo m Posted on I currently have a kicker mono dx 250.1 wired with 8 guage wiring and a kicker comp 10 svc in a truck box in the back of my car. The specs for the amp are 150rms @ 4omhs and 250@ 2omhs.

The specs for the sub are 150 rms @ 4omhs. They don't sound as loud and would like to get out as much of it as possible.

I had this set up in a truck previously. Would it be better to get a bigger box for the sub? If I do get a bigger box, should I get ported or sealed? I listen to all types of music ( rap, rock, Spanish). Or could i add another kicker comp sub with the same specs and a dual box? Also how big of an amp can I put on 8 Guage wiring? Joel Posted on 9/24/2015I have two 4x6' SPS-406 speakers, two 6.5' SPS-610 speakers & two 12' SWA-12S4 subwoofers.

If i buy a PDX-V9 5 channel amplifier, will this work & if so how would i properly do this? I'm pretty sure the amp will handle the power for all these speakers but i'm not sure if i can use the (one) sub channel for both subwoofers.

I also have 4awg wire & an 80 amp fuse. Will that be sufficient size wire & amp for this setup?

One last question is would it be better to use a capacitator or just get a yellow optima battery to handle all this power? Thank you in advance.

Buck Pomerantz from Crutchfield Posted on 9/10/2015Michael, Kicker makes two kinds of 10' CVR subs: dual voice coil (DVC) 2-ohm and DVC 4-ohm models. Which ones you have will affect what amp will work best. If you have the DVC 4-ohm models, you'll want an amp that can put out between 600 and 1200 watts RMS at 4 ohms or 1 ohm. If you have the DVC 2-ohm models, get an amp that can do 600 to 1200 watts RMS into a 2 ohm load. Kicker makes a few amps smaller than the 1200.1 that'll probably work, like their KX800.1 or CX600.1. Josh from Odessa Posted on 9/10/2015Hi Buck,I have the setup in the first example with 2 Alpine SWR-8D4 but am using an Alping PDX-M6 amp to power them.

I have them wired together for a 4 ohm load also. My question after reading a lot on OHM's law and setting the amp gain for lower RMS power subs is what is your recommendation on my amp's gain setting. If I go with everything I've read and watched on getting the right amount of voltage from the amp my gain setting is at 0. Of course having the 2 subs wired together at a 4 OHM load is like you said in your example, a 700 watt 4 ohm load so do I need to worry about the amount of volts I'm pushing to subs by increasing the gain on my amp?ThanksJosh.

Travis from Brady Posted on 9/6/2015I have one Pioneer TS-W1207D4 (12in. 4 ohm sub) and looking for an appropriate amplifier.

Ha Mode Requires At Least Two Rms Time

The Pioneer website states this sub is rated at 400rms. Not sure if that is at 4ohm or 2ohm. I'm looking at an MTX Audio Thunder 500.1 monoblock to power it. It has 4 terminals however (+,+,-,-). Minimum 2 ohm load and 500rmsConfused and need help figuring out the following:1)Is the Pioneer sub rated 400rms at 2ohm or 4ohm?2)Is the MTX AUDIO Amp good to power this type of sub?3)How should I wire it considering the 4 terminals?

(-) I think this amp is bridged internally. Joel from Yakima Posted on 8/28/2015I have two 12' JL audio W0v3 subs. They are single voice coil rated at 300 RMS and 600 watt max.

Your column was very helpful as I now understand why my 900 watt max Pioneer amp runs burning hot from the time I turn on my system and shuts off when I turn up my music too loud or a deep bass tone hits. I figured 900 watts would be enough for the subs but understanding how Amps and ohms work I know I need a bigger amp, a lot bigger. The two subs came together in a factory build JL Audio box. Can you suggest a new amp for me? I need to be able to enjoy my music for longer periods of time, as well as be able to knock my neighbors paintings off the walls from time to time too.

Buck Pomerantz from Crutchfield Posted on 8/17/2015Mark, I don't know anything about that interface harness, but judging by its customer reviews it ought to work fine with your factory receiver, that equalizer and amp. I do see that you chose two 200 watts RMS rated DVC 4-ohm subs. Seeing as they can only get wired together to form a 16-, a 4-, or a 1-ohm load, you won't be getting the amp's full subwoofer output, because the amp can't do 1-ohm and will only be able to put out 200 watts RMS at 4 ohms. You'd do better with two DVC 2-ohm subs wired. Mark from Guthrie, OK Posted on 8/15/2015will this combination work?

I am keeping the stock radio(silverado crew cab 2008 LS without BOSE) and adding a PAC AOEM-GM1416 to it for the amp, I am thinking of going with a KX8005 amp, 2 kicker C12D4 subs and a kicker KQ5 Equalizer. I did a lot of research and I need a second opinion before I sink $1000 dollars into this my vehicle currently has 4 kicker CS67 door speakers I wanted to change the pillar tweeters and go with Kickers but I am not sure which ones will fit and still give it that decieving stock look which I like. Viraat from New Delhi Posted on 8/13/2015Hi Buck,Thanks for the great article.

I have a just purchased a Hertz DS 30.3 Subwoofer which will be delivered to me this week. I got it for a steal, which is why I started my build with the subwoofer. It has a continuous program rating of 250 watts, and a peak of 500 W. Is the Blaupunkt EMA 455 a suitable amplifier (4 channel, 55 RMS)? It is available for under 70 USD here.I am looking at a 4 channel amp with a bridge so that I can power my front components (Blaupunkts, OE of the Skoda Octavia Mk1) through the amp as well. In the rear, I have a set of 4.25 inch coaxials (Stock location, Hertz, don't know the model) which I plan on running through the headunit directly.Which other amplifiers should I consider?

Does the set-up seem okay? What kind of wiring do I have to do for this?These seem to be very naive or amateurish questions, but this is my first proper car audio system!Please help!. Buck Pomerantz from Crutchfield Posted on 7/29/2015Jason, It's not the best of practices, but your scheme will work. Wire each voice coil to a pair of bridged amp channels. Use as a general guide, but pretend that instead of two subs, they're two voice coils on one subwoofer. That sub can easily handle the amount of power that amp puts out.

The tricky part is that each channel must send the identical signal to its coil or the discrepancies will create distortion and may even damage the sub. You solve this issue by using a Y-cord to send the same signal to each amp channel. Buck Pomerantz from Crutchfield Posted on 7/28/2015Ryan, Trying to run two 1500-watt subs with a 400-watt amp won't blow the amp, but wiring them together incorrectly might.

Seeing as SoundQubed HDC 12' subs come in DVC 1-ohm and DVC 2-ohm models it is crucial that you know which model you have in order to wire them safely to an amplifier. That 400-watt amplifier shouldn't stress the electrical system of whatever vehicle you have.

But if you do put in a stronger amp and then your vehicle's lights dim when the music plays, then you might need to upgrade your electrical system. Ryan Jenkins from fort sill Posted on 7/28/2015I have a Powerbass 400.1 watt amp with 2 powerbass 12s rms 550 watts. I am looking to upgrade and have decided to go with 2 soundqubed hdc3 12s rms at 1500 watts a piece i believe. My concern is is the subs going to be to much power for my amp and eventually blow my amp up? Some buddies of mine said i will need a new alternator or an extra battery along with a new amp to power subs like those. I already have a Cap but im still new at this and just need some advice. Erick from Meriden, ct Posted on 7/9/2015I have purchased Kicker DCompS12 Dual 12' Single-Voice-Coil 2-Ohm Subwoofers with Enclosure and I have them wired to a Boss Audio R1100M - 1100 Watt, Monoblock, Class A/B, MOSFET Amplifier With Remote Subwoofer Level Control.

I don't know if it's because I'm used to a sealed box enclosure but the subs do not sound too great.Should I buy a different amp? Or do you have any suggestions on a sub, enclosure, amp combo to install in a 2012 Toyota Sienna SE. Buck Pomerantz from Crutchfield Posted on 6/23/2015Jake, Alpine Type S subs come in two models: DVC 4-ohm and DVC 2-ohm. If yours are the DVC 4-ohm subs, then you should look for an amp that can put out between 750 and 1500 watts RMS at 1 ohm or 4 ohms. If you have the DVC 2-ohm subs, then you should look for an amp that can put out between 750 and 1500 watts RMS at 2 ohms.

The size power and ground cables you'll need depend on which specific amplifier you choose and will be specified in the amplifier's owner's manual and specs. Matt from St. Louis, MO Posted on 5/17/2015I have a Rockford Fosgate Punch 400.4, 4 channel amp that's about 14 years old, and it was only used for less than a year. I was wanting to use it again, and was wanting to buy 2 subs. I know 4 channel amps are not ideal for subs, but it worked great for my last system years back.

I guess bridging it to a 2 channel is what the installers did with it.On the amp, it says '50 X 4 Watts RMS into 4 Ohms with less than 0.05% THD from 20-20 KHz.' It also states '100 X 4 Watts RMS into 2 Ohms with less than 0.10% THD from 20-20 KHz.' What kind of subs would work with this amp? Or should I just not use this amp and buy a newer monoblock or 2 channel and wire that to 2 new subs? Thank you for any help!. Buck Pomerantz from Crutchfield Posted on 5/15/2015David, Three DVC 2-ohm subwoofers can indeed present an amplifier with a 3-ohm load, wired like.

The math for figuring what an amp will do with that impedance is a bit complicated and I won't go into it here. I will tell you that you should look for a mono subwoofer amp (2-ohm stable) capable of putting out from 1000 to 1500 watts RMS at 2 ohms. This should result in between 750 and 1125 watts RMS for the 3-ohm system - right on target. Avoid amps with regulated output power that is the same at all impedances - that won't work the same way.

Buck Pomerantz from Crutchfield Posted on 5/12/2015Rajeev, Car subwoofers are inappropriate in a home stereo system for a number of reasons. If you wanted to power your sub with just 500 watts RMS, the 12-volt power wires would need to be able to pass about 55.6 amperes of current. That large a power supply is rare and expensive. If a home theater subwoofer is not large enough for your planned system, try looking at a pro audio PA subwoofer. I don't know what pro audio equipment is available in your country, but an online search ought to bring up at least one pro audio dealership somewhere near you. Buck Pomerantz from Crutchfield Posted on 5/11/2015Gopinath, A watt is a measurement of an amplifier's output power; an ohm is a measure of a subwoofer's impedance; a number of one can't equal a number of the other - they're different things. They do have a mathematical relationship when the sub is hooked up to the amp.

An amplifier's output power in watts will equal its output voltage squared then divided by the subwoofer's impedance in ohms. Also, you should never use peak ratings when matching amps and subs (PMPO stands for Peak Momentary Power Output, a worthless rating), always use RMS ratings. Buck Pomerantz from Crutchfield Posted on 5/4/2015Robin, Not knowing exactly what subwoofers you have (number of voice coils and impedance) make it impossible to give advice on how to wire them together. Also, I am not familiar with any Alpine subwoofer rated for 750 watts RMS, and suspect you've quoted a peak rating, which is useless for matching subs and amps together. There are no benefits in getting a 2-channel amp to drive a subwoofer system. Most 2-channel amps can't drive loads lower than 4 ohms when bridged, and don't have enough power to drive 2 subs. Mono, 1-channel amps are designed to work with a wider range of impedances, and have tone controls and filters specifically made to help reproduce bass.

Ha Mode Requires At Least Two Rms In Excel

In an earlier I elaborated on Exchange 2010’s, what role it plays in the Database Availability Groups concept and how this role is played. In this article I want to discuss the Datacenter Activation Coordination (DAC) mode, what it is, when to use it and when not.Note that the following information is based on Exchange 2010 RTM behavior. A separate Exchange 2010 SP1 follow-up will be posted describing changes found in Exchange 2010 SP1.To understand the requirement for Datacenter Activation Coordination, imagine an organization running Exchange 2010. For the purpose of high availability and resilience they have implemented a DAG running on four Mailbox Servers, stretched over 2 sites running in separate data centers, as depicted in the following diagram:Types of FailureBefore digging into Datacenter Coordination Mode, I first want to name certain types of failures.

This is important, because DAC’s goal is to address situations caused by a certain type of failure. You should distinguish between the following types of failure:. Singe Server Failure – A single server fails. The server needs recovery (availability, fail over automatic);. Multiple Server Failure – Multiple servers fail. Each server needs recovery (availability, automatic);.

Site Failure – All components in a site (datacenter) fail. Site recovery needs to be initiated (resilience, manual).What you need to remember of this list is that each type of failure is different, from the level of impact to the actions required for recovery.QuorumWith an odd number of DAG members, the Node Majority Set (NMS) model is used, which means a number of (n/2)+1 voters (DAG members) is required to obtain quorum, rounded downward when it’s not a whole number. Obtaining quorum is important because that determines which Active Manager gets promoted to PAM and the PAM can give the green light to activate databases.With an even number of DAG members, the Node and File Share Majority Set (NMS+FSW) model is used. This means an additional voter is introduced in the form of a File Share Witness (FSW) located on a so called Witness Server. This File Share Witness is used for quorum arbitration. Regarding the location of this File Share Witness, best practice is to put it on a Hub Transport server in the same site as the primary mailbox servers. When combining roles, e.g.

Mailbox + Hub Transport, put the FSW on another (preferably e-mail related) server.So, given this information and knowing how quorum is obtained, we can construct the following table regarding quorum voting. As we can see, when using 4 nodes as in our example scenario, we require a File Share Witness and a minimum of 3 voters to obtain quorum.

DAG membersModelVoters Required2NMS+FSW23NMS24NMS+FSW35NMS310NMS+FSW615NMS8Site ResilienceConsider our example with the primary datacenter failing. Damage is substantial and recovery takes a significant amount of time and you decide to fall back on the secondary datacenter (site resilience). That would at least require reconfiguring the DAG, because the remaining DAG members can’t obtain quorum on their own since they form a minority.So you remove the failed primary datacenter components from the DAG, force quorum for the secondary datacenter and reconfigure cluster mode or Witness Server (depending on the number of remaining DAG members). After reconfiguring, the remaining DAG members can obtain quorum because they can now form a majority. And, because the DAG members in de secondary datacenter can obtain quorum, the Active Manager on the quorum owner becomes Primary Active Manager and the process of best copy selection, attempt copy last logs and activation starts.Split Brain SyndromeConsider your secondary datacenter is up and running and you start recovering the primary datacenter. You recover the server hosting the File Share Witness and both servers; network connection is still down.

A problem may arise, because the two recovered servers together with the File Share Witness form a majority according to their knowledge. So, because they have quorum they are free to mount databases resulting in divergence from the secondary datacenter, the current state.This situation is called split brain syndrome, because both DAG members in each datacenter can’t communicate with DAG members in the other datacenter. Both groups of DAG members may determine they have a majority. Split brain syndrome can also occur because of network or power outages, depending on the configuration and how the failure manifests.Datacenter Activation CoordinationTo prevent these situations, Exchange has a special DAG mode called Datacenter Activation Coordination mode.

DAC adds an additional requirement for DAG members during startup, being the ability to communicate with all known DAG members or contact a DAG member which states it’s OK to mount databases.In order to achieve this, a protocol was devised called Datacenter Activation Coordination Protocol (DACP). The way this protocol works is shown in the following diagram:. During startup of a DAG member, the local Active Manager determines if the DAG is running in DAC mode or not;. If running in DAC mode, an in-memory DACP flag is set to 0. This tells Active Manager not to mount its databases;. If the DACP flag is set to 0, Active Manager queries the DACP flags of all other DAG members it has knowledge of.

If one of those DAG members responds with 1, the local Active Manager sets the local DACP flag to 1 as well;. If the Active Manager determines it can communicate with all DAG members it has knowledge of it sets the local DACP flag to 1;. If the DACP flag is set to 1, Active Manager may mount its databases.Note:So, assume we enabled DAC for our example configuration and we recover the servers in the primary datacenter with the network connection still down. Those servers are still under the assumption that the FSW is located in the primary datacenter so – according to knowledge of the original configuration – they have majority. When starting up, their DACP flag is set to 0. However, they can’t reach a DAG member with a DACP flag set to 1 nor can they contact all DAG members they know about. Therefore, the DAG members in the primary site will not mount any databases, not causing split brain syndrome nor divergence.If the recovered servers in the primary datacenter come online and the network is already up, the nodes will also not mount their databases because part of the procedure for switching datacenters is removing the primary datacenter DAG members from the DAG configuration.

Ha Mode Requires At Least Two Rms 2

So, the DAG members in the primary datacenter contain invalid information and will be denied by the DAG members in the secondary datacenter.Implementing DACDatacenter Activation Mode is disabled by default. To enable DAC, use the Set-DatabaseAvailabilityGroup cmdlet using the DataCenterActivationMode parameter, e.g.Set-DatabaseAvailabilityGroup –Identity –DatacenterActivationMode DagOnlyNote that DagOnly and Off are the only options for the DatacenterActivationMode parameter.MonitoringIf you’ve configured the DAG for DAC mode, and LogLevel is sufficient, you can monitor the DAG startup process using the EventLog. The Active Manager holding quorum check status every 10 seconds. It is responsible for keeping track of the status of the other DAG members. When sufficient DAC members are registered online, it will promote itself to PAM (like in non-DAC mode), which functions as the “green light” for the other Active Managers.The Active Manager on the other DAG members will periodically check if consensus has been reached:If the Active Manager holding quorum has promoted itself to PAM, the Active Manager on the other nodes will become SAM. After this the activation and mounting procedure will start.LimitationsUnfortunately, it’s not an all good news show.

DAC mode in Exchange 2010 RTM can only be enabled when using a DAG with 3 or more DAG members distributed over at least 2 Active Directory sites. This means DAC can’t be used in situations where you have 2 DAG members or when all DAG members are located in the same site. This makes sense for the following reasons:. In Exchange 2010 RTM, DAC only looks at the DACP flag querying DAG members.