Car Subwoofers to Home stereo subwoofers?

Wow, where to start with you.

I am a noob, huh? Well lets see, I live in LA, have a AA in audio production, a BA in Broadcasting, and a BS in electrical engineering. I worked for 5 years as an on set sound recorder (until we had to give up our Nagras for digital), 3 years as a sound engineer for a recording studio (mainly using ProTools), and the past few I have been employed by harmon/kardon in their R&D (research and development) department testing specs for new products. And then there's the thousands of posts I've done here at aD the past six years to help properly inform people seeking help and diverting them from people like you who are brand new to forums such as this and think that they know everything. I've never bothered to post my educational and professional background because in the end it really doesn't matter what background you have, but rather how well you can help others seeking help.

First let me address the topic of subwoofers.

I don't know how much simpler to put it then this: car subs are designed to cars, and home subs are designed for homes. There is an incredible amount of engineering put into them based on their end application. They are more complicated than a frame, voice coil, magnet, and cone. I could sit here and post the physics and mathematics behind it, but you're probably too stupid and young to understand anything above basic arithmetic. Subwoofers, along with all other speakers are only efficient in the cubic footprint they are designed for. They're more complicated than just moving air to create sound waves. Different systems are designed to have to reproduce sound waves at a certain distance. Some are only efficient at a few feet (such as car subs.) Others are designed to have sound waves carry for much further. Home theater speakers, especially subs, are designed to be efficient (accurately reproduce various frequencies) for dozens of cubic feet. If you have a car sub and a home theater sub with the same size and specs side by side, they sound completely different. It is really a basic concept, and if you know as much about subs as you claim, I'm surprised you can't realize this. Here's a nice simple question for you: If the sub doesn't matter, and car and home subs are the same, and only the enclosure matters, then why would manufacturers such as JL Audio, Sony, Infinity, and many more BOTHER to make both home and car subwoofers. If what you say is true, why not have one line of subs and use them in both applications? Hmmm...are you starting to see my point?

Now about ohms and amps. 90 percent of home amps and speakers run on an 8 ohm system. Higher end systems run between 6 and 18 ohms. My Electrovoice Sentry 100A studio monitors run on 6. But generally speaking most systems are 8 ohms. The reason why I mentioned ohms is so that he didn't fry a home stereo by connecting a sub with a lower load ohm than it could support. The types of amplifier circuits (broken into different classes) are also different from home systems to car systems. Car systems have generally lower quality chips that have a higher THD (total harmonic distortion) but a high output volume. That way they run more efficiently on a 12 volt direct current system. You also can't integrate car and home systems because their signal levels are different. Line level for home stereos is around 1 volt. Car systems run on up to 4 volts because the amps can accept a much higher signal level because they don't have preamp circuits to process signals.

Thats great that you said he needs a 110 volt powered amp to run his sub. I never questioned that. Would you like a cookie or something for actually saying something correct? Read all the posts I posted way earlier when the original person started this thread...I said that same thing along time ago. Try reading the whole thread you moron.

I have posted so much useful and correct information about car vs home systems, ohm loads, and sub amps from the very beginning of this thread (and many others), so why don't you start by reading this whole thread from the beginning. You come at the end and add your pointless and redundant comments to this thread, AND THEN have the balls to call me a noob and that I don't know what I'm talking about? Let me take a guess here. You are 16 years old, probably live in a town of 200 people in the middle of nowhere, famous for making moonshine and growing corn. You have just gotten your first car, and have spent all your money working at McDonalds on your car stereo, and now you magically think you know everything about audio.

If you want to gain ANY respect around here, have people actually take your advice, and not get banned for disrespecting long time members, you seriously need to adjust your attitude.

 

Mind if I drop in?

brettus, you have djscoop way wrong. He teaches college level digital audio and one of the top AD audio experts. What he says is correct. Yes, you are a bit correct as well. You can use car speakers in the home but why would you do that????

Do yourself a favor, check out the stats before you come on talking like an expert. Base responce is ALL about power. Battery driven devices are pitful matched against AC. I am talking wattage and base responce. If your speaker does not advertise the base responce or wattage that is because they do not want you to know how poor they are. The lower the base notes the more power it takes. I am not talking a little power. How is a car battery to deliver 200-400 watts? It is well known you pay a small fraction of the cost of a powerful car sterio for an equivelent house sterio. Subwoofers are ALL about base responce. I have a book shelf that delivers 4 Hz. That will pull over 1,000 watts at half volume if a low note is played. It is fused with a 1,400 watt fast blow which blows if I play some pieces over half volume. Even at less than half volume the low note will vibrate you and the room. You you really claim your car battery can deliver power like that? !!!

 

Great survival advice ddp!

brettus, I over reacted with you. I reacted more to your rudeness then what you stated. I reread your posts. A good deal what you stated was valid. I will credit you as being a car stereo expert.

All speakers are DC so they can be used in the car or home. The speakers I talked about are 4 Ohm not 8ohm. You need serious amps to power anything under 8. They are easier to do in the home not harder.

Which brings us back to the original question... wiiguy, all you need to do is find a powerful amp. Without reading this whole thread I would recomend a preamp and 2 power amps. The one that drives your woofer run it in mono. Although one big amp will do it 2 smaller one will be way cheaper.

 

Thanks Mez I have been doing this a little while

Let me now apologise to djscoop, the noob remark was way out of line so again I am apologise.
I do still disagree with some of the things djscoop is saying but will not get into an argument anymore.
Alternatively for a sub amp you can use a Pro Amp such as the Behringer Europower EP2500-
This amp is 2ohm stable also.

This amp will requires the use of a bump or clean box- to convert a unbalanced signal(RCA) into a Balanced signal (XLR).

For more explanation have a look here-.

Good Luck with whatever path you go and again sorry to all that I have offended.

 

I am more than happy to have a conversation about this topic...what is it that you disagree with?

 

Hi, it’s quite a coincidence that yesterday this wild thought came to my mind and today while exploring on the net the first discussion that I came through is exactly about the topic I wanted some help/guidance for. Anyways before I start letting out my curiosity here, let me explain about my self. I am a non technical guy however, I prefer doing experiments on sound if my pocket allows. I have a home theater setup with Denon as my 5.1 receiver and set of infinity speakers with paradigm 12 inch as subwoofer. (Before starting off here, I explored my sub and tried to find the ohms that it required but I couldn’t. Anyways I am sure that my receiver sends out 8ohms signal to rest of the speakers but I am not sure about its signal to the subwoofer).

My question (especially to djscoop) here is that I want to add another subwoofer to my home theater setup. Going for a home theater subwoofer is an expensive choice in my country and choices are limited as well so I thought of adding a car subwoofer to my setup. I went to the local car audio store and found out that I can get a mono car amplifier (brands available: sony/kenwood/pioneer) with 1000-1800w output (with 4ohms output) and I can get a good 12inch-15inch woofer with in a local made bass tube and can use the same in my setup. The technician at the shop told me that I need to get a good transformer/adapter to convert the 220v (standard voltage here) to 12v with the high amps required (as you mentioned in some of comments).

After reading all your comments they sounds quite accurate to me that if both type of subs can be used in one environment than why the heck manufactures are making two different lines for sub, one for the car and the other for the h.theater. But if I look at my pocket and accepting the slight difference in sound, I can proceed for adding the car subwoofer in my existing setup since the same specs home theater subwoofer costs a fortune here and that I can’t afford for the moment (second hand options are out of the scope and are not recommended here).

Being a BASS lover, the idea of adding a 15inch woofer with an a car amp, powering the car amplifier with a required convertor/adaptor and connecting the amplifier with standard jacks to my 5.1 receiver subwoofer port attracts me a lot but still I should look for an expert advise like your self. If you agree to the idea kindly let me know. Please also let me know how to handle the 4ohms vs 8 ohms issue since my plan is to add one woofer rather two.

 

I am thinking something must be VERY wrong with this picture. You are not comparing apples to apples. I would read the fine print. I would check what the RMS wattage is.

They can play with peak wattage but RMS is a standard. I doubt that most car alternators are more than 50 amp. 50x12 or 600 true watts. When I used to know, they were more like 25-30 amps. How do you get 1800 watts when your alternator is only puitting out 600 and you need most of it for other things? Do you realize how fat a wire would have to be to deliver that kind of wattage at 12 volts? Have you ever seen wire that carries 300 amps??? Your stove takes a 30 amp wire (one tenth that) and that is hard to bend when there are 3 wire. Each wire is hard to bend for a tight loop.

The Rolling Stones bragged in one of their songs that they could blow a 50 amp fuse. That kind of sound was not made for a car. My bet is your 1800 watt amp is really only 50 RMS per channel or so. That is a wild guess on my part.

I have a 400 RMS per channel amp. It is 50-60 pounds. The power wires are either super heavy copper or heavy silver. I really doubt your 1800 w amp is several times more powerful than that.

 

hey sinbaad,

well what you want to do definitely is possible, I just want to point out a few issues you might have to deal with though.

The first problem is using a car amplifier. While you can get a mono sub car amp for pretty cheap, the power supply you would need to run a 12 volt car amp off of a 110 or 220 AC system is so expensive, that between the amp and the power supply it would be cheaper to buy a home sub amp. a power supply that can handle that much current draw is pretty big. Its not a small consumer level wall-wort type power supply. You will need a professional bench top supply, and those are usually a couple hundred dollars. My recommendation is the same suggestion I had at the beginning of this thread. Purchase a sub amp designed for a home system that runs off of 110 or 220. Like this one here:

http://cgi.ebay.com/Cerwin-Vega-Sub...66:2|39:1|72:1234|240:1318|301:0|293:1|294:50

Now this one is obviously less than 1000 watts, and whether or not it has a 4 ohm output is something you could ask the seller. but there are many more amps you can find on ebay just like this that do in fact output 4 ohm loads and have a higher wattage rating. you really don't want to install a 1000 watt sub in your home if you think about it. first, you already have a high end sub. having a second sub with that high of an output would first drown out your other sub, and second be so powerful that it would likely overpower the rest of your system.

My other concern is that you already have a nice high end home theatre sub. The problem that I see is that by adding a second sub that is a car sub, high wattage, and in a home made tube, I don't think the quality of bass would be anywhere near what your current Paradigm can produce. For your tube to be tuned right it must be the exact right size according to the cubic feet required by the speaker. if it is tuned differently than the home sub, it will sound like two different frequencies, and your bass will sound muffled and very unclean.

Like I've said before, I'm really not a fan of integrating a car stereo system into a home theatre system, simply because they are not designed to be compatible and the quality in performance is so different. It is possible, but after buying a car sub, building an enclosure, purchasing a massive power supply, and a car sub amp, it would probably just be cheaper to buy another home theatre sub. I personally am a big fan of the high wattage small sealed subs (I have a ten inch bob carver sunfire that produces 2700 watts of power) but they are rather expensive. mine cost over $3000 five years ago. but someone else here posted this sub, which is a ported tube design and much cheaper. might be worth checking out...

http://www.svsound.com/products-sub-cyl-pc12_nsd.cfm

 

hey Mez in regard to your post about amplifier current draw and alternator sizes, I'm not a mechanic or anything, so I don't know what a typical alternator outputs. However I do know that for a small to moderate stereo system (under 1000 watts) the stock alternator works fine. This is because amplifiers are usually hooked up directly to the car battery, which can store a pretty large amount of current. The alternator then constantly recharges the battery as the car is running. Also for high watt systems you can also add a large (1.0 farad) capacitor to the system which keeps a large amount of current stored that can be accessed on demand if the battery can't supply enough current. the effect of not using a capacitor when one should be used can be seen when people crank their systems and you see the headlights and tail lights dim as the bass hits.

also, about a 30 amp wire running your stove is kinda different. its funny you mention that because before I became an audio nerd, I worked for Thermador, Viking, and Bosch doing warranty service for their kitchen appliances. LOL. most built in ovens run on a 30 to 50 amp circuit, depending on if they are a single oven or double oven, and how many elements they have (bake, broil, convection...). but that current is running through a 220 volt system, so the gauge of wire is much smaller than would be needed for a 12 volt system.

 

Yes but amps are amps! 220 gives you almost 20 times the power or watts as 12. Wire is sized by the amps. 1800 watts at 12 V is 300 amps or is my math off? My point is if the wires are light that is telling you what the amp can put out. Better yet what is the fuze rating? I doubt that it is 300 A for a 1800 w RMS system. I doubt that it is more than 30.

RMS is much closer to raw current. I am sure however they are mesuring the wattage for car amps is not remotly close to RMS. That is why I stated you are compairing apples to oranges. Get the RMS wattage for the amps to compare like to like. Only then can you make an educated decision. I also suspect distortion to be less at peak power of a home sterio than a car sterio.

As far as the battery goes, it can allow short bursts of a great deal of power but only bursts.

The whole point is watts for a car sterio and watts for a home sterio are calculated differently. I would be very suprised if car amps had a better bang for the buck than a home sterio. I am really just saying buyer beware.

 

hey mez.most automotive alternators put out 60amps plus these days with a lot of domestics putting out in excess of 100a.my two cents on this one....sounds like a lot of crap to go to when you can buy a powered sub relatively cheaply.by the time you go and buy what you need to use car subs in your house you could have bought a decent powered sub.at least where i live you can.cheers.

 

well car amps don't come with the power cables included, but as far as I know its pretty standard. Car amps use 8 to 0 gauge power cable.

One thing about car amps that we're overlooking is the type of circuitry that car amps use. Car amplifiers use Class D circuitry (called switching amplifiers,) as opposed to class A or AB (called linear amplifier) for home stereo systems. The class D amplifiers are much more energy efficient. Class A and AB circuits are very inefficient. only 10 to 20 percent of its power consumption is actual signal output, the rest is heat. Class D circuits use a different type of transistors. I won't bore you guys with the super technical details, but basically class D transistors are either on or off. when they are on, the current draw is at the max but voltage is zero. when they are off, the current is zero but the voltage is at max. basically that means that a minimum amount of current is drawn when the transistors require a large load, and vice versa.

the downside of class D circuitry is that signal quality is much less than that of other classes of amplifiers. They implement pulse width modification to convert the input signal to a sequence of pulses which makes the transistors as efficient as they are.

what all this translates to is that the output wattage of an amplifier does not mean that is the wattage that the amplifier draws.

 

aldan, I will take your word for it. I figured they might be a lot bigger not that big but I will take your word.

djscoop, you are missing my point all together. I am working out is it bigger than a bread box. This thread is about buying car amps for home use because they are a better bang for the buck. I DON'T KNOW if they are a better bang for the buck or not. I am VERY suspicious that the watts that measure the car amps are not even close to the watts that measure home sterios. My home amp way less than 1000 watts has huge wires and have dimed the lights with a booming base note even at low volume.

All I have continued to do it make you all think before you buy. The wire thickness will give you if it is bigger than a bread box. The car amps I have seen had tiny wires for the proclaimed wattage. The amps them selves are also much smaller and weigh less than their home counter part. These facts should make you think. Is that so hard to fathom?

 

hey Mez yeah I definately get your point of the rating of wattage for home stereos vs. car stereos. I'm not at all defending car stereos, just sharing the limited knowledge I have on auto stereos...I know a lot more about home systems.

The only other thing I can add is you mentioned the car amps are much smaller and lighter than home systems. this again goes back to the types of circuits. class AB amps output 90% of their energy as heat. Class D circuits on the other hand are very energy efficient, and produce very little heat. this allows for car amps to not require massive heat sinks, which reduces the size and weight of car amps.

 

The circuts are a another piece of the puzzle. So car amps my be more than twice as efficinet. Who knows, maybe for woofer a car amp might be OK. I am sure the less efficient circuits produce a cleaner sound. Maybe that will be less hearable for low notes or maybe it is worse. This is the first serious discussion I have hear on this subject.

I built my old dinosaur. The Zener diods were the 'quality' componants and they burn out from time to time. They and some of the other diods are the heat generators.

 

yeah class D circuits are way more efficient that class AB or class A designs but the quality of the sound have a ways to go before they can match the quality of AB ones. There are a few high end very expensive home theatre receivers that use class D circuits that sound very good, but that is due to the really expensive preamps and signal processing circuits incorporated in them. But an average $500 receiver with class D transistors can't compare to the AB class, yet. That is why class D circuits are popular in car sub amps because of the narrow frequencies they have to reproduce, not to mention they are energy efficient and draw little heat.

 

Hi Dj Scoop,
i took your useful advise and dropped the idea of getting a car subwoofer for my home theater. I have another question, though its not related to the subwoofers now. Tell me how important are the front channel speakers in a home theater setup, i mean in movie watching only. I have seen people spending a lot on these speakers, is it really worth it for movie effects only? (i am not too much into audio now). My interest is in replacing my current JBL E100, something that i got long time ago . these have two 10 inch drivers each and sound very soft while listening to audio and worth the value however, i am not sure if they can be considered great for the movie front and back effects as well.. anyways, now i am considering shifitng to Klipsch and the top of the line range but is it really worth spending the buck.. i already have a klipsch center which is quite opposite to the JBL..... Cosidering your past professional life, i couldnt stop my self asking you, so ur input required.. thanks

current theater specs:
denon avr 2808
Jbl e100 (Front/Back)
klipsch rc62
carver power: tfm55

 

You own ears are the best judge. Why pay more for what uou can't hear. Some of the audio for movies is even more demanding than regular audio.

 

hey sinbaad

the reason why the center channel is so important and why people spend so much money on it is because for surround sound movies, 90% of the dialogue comes from the center speaker. so yes, its pretty important. you don't need to spend a ton of money though, just get a good name brand one like Sony, Harmon/Kardon, JBL, or Infinity. NOT a crappy particle board made in china brand like KLH.