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Car amp and car sub in home

 

New member
Username: Lambournledge

Lambourn, Berkshire United Kingdom

Post Number: 2
Registered: Jul-11
i'm trying to create a sound system for my turntables in my house using a car amp and car sub (which are just lying in my room and need to be put to use!). is this possible? my amp is 2000 watt and my sub is 1000 watt. im planning on getting some active monitor speakers to go with this. anyone know how i go about creating this set up? need to know if its worth it as really don't have the money to buy a home sub and amp! any help will be much appreciated! thanks
 

Gold Member
Username: Superjazzyjames

Post Number: 1611
Registered: Oct-10
First off, you're best off using car audio gear in a car and home gear in your home. Each was designed for a specific purpose.

I only ever heard ONE pair of car speakers used in a home that sounded decent. Not great, not good, decent.

How do you plan to power this amp?
 

Gold Member
Username: Illuminator

USA

Post Number: 5548
Registered: Apr-05
Yeah trust me. I've ran car audio in the home before and while it sounds okay, it's just not like home audio. I've even had my $400 diamond component speakers hooked up and it was nowhere near my cheap Onkyo surround speakers (they're little 4" speakers in a plastic "cabinet"). The same goes for subwoofers and my JL 10w6v2 subs and PPI amplifier. Sounds good, but nothing like a home audio sub.

You would also need a MASSIVE DC power supply for that kind of wattage amplifier, which would be extremely cost prohibitive and very dangerous (sparks etc.). Since you haven't mentioned names or models, I'm assuming the sub and amp are garbage anyway (and such high powered subs and amplifiers are meant for sound pressure and not sound quality anyway).
 

New member
Username: Lambournledge

Lambourn, Berkshire United Kingdom

Post Number: 7
Registered: Jul-11
oh okay thanks.. definitely put me off doing it now! although i was going to power it through a car battery charger.. may i just ask what is the actual difference between a car sub and a home sub? and are there any home audio subs you reccommend? is it best to get one with a built in amplifier?
 

Gold Member
Username: Superjazzyjames

Post Number: 1612
Registered: Oct-10
First Question: How much do you have to spend on a sub? If you can tell me this, I can recommend models in your price range to check out.

Getting a powered sub (sub with built in amp) will, in all likelyhood, cost less than buying a passive (non-powered) sub and a seperate amp will likely cost more and take up more room. Buying your sub and amp seperately will allow you to choose the type of amp you want to power the sub with. It will also, if done right, potentially sound better than a powered sub. It basically depends on how much room and $ you have to play with.

Using a car battery charger as a power supply? I can't say for sure, but this just doesn't sound like a good idea to me. Knowing that a charger is designed for charging batteries and jump starting cars gives me serious reservations.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 16374
Registered: May-04
.

"You would also need a MASSIVE DC power supply for that kind of wattage amplifier, which would be extremely cost prohibitive and very dangerous (sparks etc.)."







Sparks?!


ETC?!!!









What the he!! is "ETC" when it comes after the sparks?













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Gold Member
Username: Superjazzyjames

Post Number: 1614
Registered: Oct-10
Jexx, if the power supply is made properly, there shouldn't be sparks or other safety issues. I am not aware of any companies making power supplies for using car audio gear in the home. I am guessing that since car audio is designed for use in a car, there is no real market for such a unit.
 

Gold Member
Username: Illuminator

USA

Post Number: 5552
Registered: Apr-05
Jan, after sparks come fire. Then insurance claims...know what I mean? I see nothing helpful about your post in this thread. If you're still mad about the Sherwood dealio, please keep your anger in that thread as I believe we can work it out there.

James, sparks are still possible if the diametric power wires touch each other (ask me how I know...). In home audio, power wires don't have the chance to touch each other unless something is broken/severed. There are companies that make such power supplies for places like Best Buy and other stores to demo car audio. But these are very costly.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 16377
Registered: May-04
.

"... may i just ask what is the actual difference between a car sub and a home sub?"



Gentlemen?




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Gold Member
Username: Illuminator

USA

Post Number: 5553
Registered: Apr-05
Although this isn't pertaining to sound, home subwoofers are generally less durable (made out of treated paper and flimsy baskets) because they don't need to go through intense heat/cold and are subjected to more dust, moisture and the like than usual. Plus car audio boxes have more potential at getting tossed around a bit during driving.

This is just anecdotal, but car audio subs tend to go lower (Hz) while home subs tend to go louder (dB).
 

Diamond Member
Username: Wingmanalive

Www.stainles... .ecrater.com

Post Number: 24911
Registered: Jun-06
I'd say holy crap but this comes up so many times that it's such a common question.


Don't do it. Aside from the power efficiency issues you also have fire hazards to deal with. Think about how you're going to properly ground that car amp, in a house.

Plus why would you want to? The difference in sound quality between home/car audio is like comparing strawberries to nuts.


Just scratching the surface of this bad idea YEARS in the making





I can run my snow blower in my living room if I really wanted to.


But why?
 

New member
Username: Lambournledge

Lambourn, Berkshire United Kingdom

Post Number: 8
Registered: Jul-11
the main reason for me wanting to do this is because i've got an expensive car sub and amp just lying in my room and if using this for my turntables meant saving me 400+ quid on home gear then it was worth a query.but thanks for your help and i shall start saving now!
 

Gold Member
Username: Superjazzyjames

Post Number: 1616
Registered: Oct-10
The difference between car subs and speakers and home subs and speakers, in addition to what Jexx said is the design. The inside of a car, even a large SUV is much smaller than a room and car speakers are designed to work in these small spaces. Home spkrs are designed to work in rooms.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 16382
Registered: May-04
.


OK, let's deal in some facts here. You can use a car sub in your home. Whether you prefer the sound of a car sub or a home sub depends; first, on what you like in the way of subwoofer sound, and, second, how the sub and its enclosure have been designed.

Raw drivers - the "speaker" part of your speaker - are designed around certain parameters which define their mechanical and electrical values. In a low frequency driver - a "sub" - these values are described as Theile/Small parameters and the congregation of values informs a designer of the approximate sound quality of the driver itself. So when you see specifications for a raw driver which read like this; Specifications: • Power handling: 400 watts RMS/700 watts max • VCdia: 2-1/2" • Le: 1.04 mH • Impedance: 4 ohms • Re: 3.3 ohms • Frequency range: 23 - 1,000 Hz • Fs: 25 Hz • Magnet weight: 150 oz. • SPL: 89 dB 2.83 V/1m, 86 dB 1W/1m • Vas: 3.00 cu. ft. • Qms: 3.12 • Qes: 0.58 • Qts: 0.49 • Xmax: 14.3 mm • Dimensions: A: 12-3/8", B: 11-1/8", C: 5-3/8" you are seeing the T/S parameters for that specific driver. An experienced designer can look at those T/S parameters and deduce several different things from the basic numbers.

First, the numbers suggest which sort of enclosure the driver can work in to maximium advantage. Second, the designer can tell whether the completed speaker and enclosure will have bass response which is best suited to a car or a home environment and how to shift the response of the driver/enclosure to accomodate either - if that is at all possible with that specific driver. Car environments are not only smaller in cubic volume than are any domestic rooms but they have, by way of the total cubic volume, their shape and the placement of the sub within the space along with the typically less than rigid surfaces, frequency peaks and dips which are vastly unlike those of a typical domestic home. By manipulating the final assembled values of the driver in the enclosure the designer will be able to model a subwoofer which is best suited to one or the other environment. What works well in one is very unlikely to also work well in the other. But that comes down to your taste first of all. If you don't mind sloppy bass that is meant for a car, then whatever comes out of the sub will suit your tastes. This then becomes a "suck it and see what comes out" affair. You won't know until you hook everything up and try it out.


When you say you have a "sub", I assume you mean you have a complete subwoofer enclosure with a driver mounted inside the cabinet. It's quite possible the T/S parameters for your driver are better suited to a different enclosure which would then make the sub useable with a fair degree of success in your home. However, if your idea is to not spend any money on this project, then you needn't even concern yourself with the values of the raw driver as you will need to redo the enclosure to make the sub work in your home.


Your amplifier is another issue all together. Automobile amplifiers are generally crap when it comes to use in your home. Of course, this is again a matter of taste as to whether you agree with that statement or not. Anyone with a bit of sense should recognize the fact it is truly impossible to achieve "2000 watts" when the power source for the amplifier (the car battery) can deliver no more than 12 volts DC. So a lot of of fakery and BS goes into car amplifiers. They are nowdays almost all class D circuits which are not well suited to home audio according to a home audio enthusiast's preferences. They rely on their particular sort of power supplies to come up with the wattage numbers they boast and those power supplies are typically very noisey when it comes to listening to music in the much quieter environment of your home. Now, possibly the music you prefer doesn't give a hooty whistle about quiet. Then it's quite possible a car amp won't be of concern to you in your home system. Only you can decide but, in general, car amps sound very weak, thin and lean inside a domestic room. What you heard in your car is probably not what you will hear in a room. Then again, until you hook it up and give it a good suck, you won't know for sure.

Powering the amp is your main problem here as you need 12 VDC and not 120Volts or 240Volts AC. As has been mentioned, there are power converters which are intended for the purpose of supplying 12VDC stepped down from a 120/240Volt AC source. They are expensive and not truly meant for projects such as you suggest. Do not use a car battery as the fumes from the battery will be hazardous when confined to a room. I would also suggest you not try a battery charger since the high current draw from your amplifier can exceed the limits of a slow charge device and you'll risk both damage to the charger, possibly damage to the amp and the possibility of some hazards to your safety should you repeatedly blow fuses or circuit breakers in the charger.

The best way - and the least expensive way - to run a 12VDC source in a room is to use a battery which is meant for that purpose. There are various types of batteries available which are designed to output 12VDC. The sealed lead acid batteries used in devices such as "exit" signs in commercial buildings are the best known and probably the least expensive at this tme. You'll need to determine the amperage draw of your amplifier and buy a battery which exceeds that current limit by a fair margin or you'll not be satisfied with the final results. Consider here that car amplifier get their wattage specs by relying on a car battery which outputs as much as 60+ amps of current. There are no SLA's or other type of battery intended for indoor use which have such high current values. So, the battery you select will by necessity result in significantly lower wattage from your amplifier and that will result in your 2000 watt amp being more like a 20 watt amp.

Since batteries cannot supply an infinite amount of voltage, you'll also need to invest in a charger meant to supply a "floating" charge to whichever type of sealed battery system you select. Even a relatively small 12VDC SLA battery and a suitable floating charger will set you back about $100 or more.


If you go the route of a SLA battery plus charger and a new enclosure for your subwoofer's driver, you'll have invested about $200 minimum. There's nothing that you know - since you don't indicate you presently understand T/S parameters - which would suggest whether after spending that amount of money you would have a workable system or you would have wasted about $200 you could have invested in equipment actually designed and intended for home use. In any event, you will have kloodged together a jerry rigged system that probably still doesn't do much more than make less than listenable noise. If you skimp on any of the set ups, you'll have put yourself and your home at risk.


If you still prefer to explore this approach to audio, go over to the car audio section of the forum. This is a question that comes up frequently in this section - didn't you even bother to look at the archived questions here to see if you could find an answer first? - and from the perspective of someone used to the quality of home audio, the answer is always the same. Car audio guys think in entirely different terms than do home audio people. We frequently have to explain to car guys that home audio operates under vastly different rules. But I suspect the same question gets asked over there too. I don't doubt at least of a few of the whizbangs in the car audio section have work arounds for all the problems you'll face trying to accomplish this system in your home.


.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 16383
Registered: May-04
.

Now, gentlemen, bookmark this thread for future reference. That way you can skip all the hyperbole about sparks and unreliable speakers the next time this question comes up.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 16387
Registered: May-04
.

"Car audio guys think in entirely different terms than do home audio people."


For example;

" Need some suggestions on an amp guys. New or used if someone has something or knows somebody that does. Budget of around $300. Need something that does 1200wrms @2ohm."

"Looks to me like the BC2000 should do 1200 watts on 2-ohm reactive load. I know they were $299.99 shipped during the pre-sale, but now that they are in stock (you have to call Crescendo to order them) I think the price went up to $330."

"So it looks like crescendos only do rated @ .25 ohms. I wonder if they can handle that load for long?"

"They do rated at the impedance claimed. Look under calculated impedance. For example for the BC2000 at 1-ohm, due to box rise the impedance is actually 3.62-ohms, and its still putting out over 1kW. It is safe to say this box rise is due to the box design and the frequency used during the clamp test, you won't have that much rise throughout the entire frequency range. Im sure the amp can't handle a .25-ohm load on music for very long."





One quarter of one Ohm?!!!








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Gold Member
Username: Superjazzyjames

Post Number: 1617
Registered: Oct-10
Jan, one question. In your post 16387, who and what are you responding to? I only ask because I don't see any post here with references to 1200 watts, 2 ohm loads or 1/4 ohm loads. So, are you incorporating a conversation from another thread into this one so as not to repeat the same conversation? Or are you responding to one of those posts that magically dissappeared before I saw it?
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 16388
Registered: May-04
.

Another thread, james.
 

Gold Member
Username: Superjazzyjames

Post Number: 1618
Registered: Oct-10
Ok!
 

Gold Member
Username: Illuminator

USA

Post Number: 5559
Registered: Apr-05
Jan that's a great post concerning the speaker part, but definitely not definitive in regards to car audio in the home.

A MUCH better 12vdc source is NOT a battery and charger, but a dedicated 12v DC power supply from the likes of Tenma or Astron. These do get pricey when you go over 30A, but are much safer and much easier to use. They go up to 70A which is more than sufficient to power MANY of the bigger car amplifiers (and you get a nice amperage+voltage meter on many of them):
Upload

ebay is the best place to grab these. Typically there is a negative and positive terminal on the back and that's it. Simple. The above unit is on ebay and will sell for a little under $100. The 70A units are $300ish.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 16394
Registered: May-04
.

That's another way to go. But, first, the op stated he didn't want to spend money. To me that means either way he powers the amp is not going to fit into his scheme. Second, I suspect at that price range the power supply you show is a switching type? That would be OK for driving a subwoofer but less than great for anything above 100Hz when driving the typical car amplifier. His amp still won't develop the stated wattage when driving a simple eight Ohm - or even a four Ohm - load when driven from your power supply.

Safer? I don't see any safety issues with either power source. The SLA's are fine in a home environment and are used by a good number of listeners who use T-amps or other chip amps - myself included when I use my T-amp. Either way, you make a single connection between power source and the amp, nothing fancy and certainly nothing dangerous. Either way you have this fairly large box running the amplifier.

The more conventional power supply can - at a cost - supply higher current capacity than will a SLA supply but now we're talking about how to spend $400 and the op would do much better putting that amount into real home audio gear IMO.


.
 

Gold Member
Username: Superjazzyjames

Post Number: 1622
Registered: Oct-10
"...and the op would do much better putting that amount into real home audio gear IMO."

That's the bottom line. The op has already stated that he has scrapped his plans to run a car sub in his home. So, let's see if we can get an idea of how much coin he wants to spend on a sub and try to help him get one that'll be as satisfactory as possible within his price range. Okay?
 

Gold Member
Username: Illuminator

USA

Post Number: 5561
Registered: Apr-05
Jan, that is true about anything in the higher frequencies: with the switching power supply there is a minimal amount of hum above 300Hz when the volume is low. But since the OP is using this for a subwoofer application, it's not as big of a deal.

I suppose it's more safe in the sense that you don't have to continually hook up the power wires to a charger.

Though at $100 vs. the $200 option of the battery and charger, and trying to save money, the power supply fit his needs better.

But really, as James said. The bottom line is spending money on some home audio gear is the better way to go. A nice home subwoofer can be had for 100-200$, especially with using ebay or craigslist.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 16397
Registered: May-04
.

"I suppose it's more safe in the sense that you don't have to continually hook up the power wires to a charger"


That's the reason for including a floating charger with the battery. A floating charger automatically stops delivering current when the battery reaches a high percentage of charge - near 100%. It remains physically connected to the battery though it will not be "in circuit" until the battery's charge drops sufficiently. With SLA's the battery is drained almost to "dead" before the charger kicks back in if there is reasonable current draw on the battery. Otherwise, the charger will constantly top off the battery, say, in between listening sessions, so there will always be maximum battery life available. With a floating charger the amp is never drawing current directly from the charger and the battery cannot be over charged. This is the system used in "Exit" lights in commercial buildings and it was designed in such a way no one had to climb up to disconnect a charger everyday.




.


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Gold Member
Username: Illuminator

USA

Post Number: 5563
Registered: Apr-05
Then there ya go, different strokes for different folks.
 

Gold Member
Username: Superjazzyjames

Post Number: 1623
Registered: Oct-10
"Then there ya go, different strokes for different folks."

Well put Jexx.

Since we're all in agreement that car audio is best used in a car and home audio is best used in a home, why don't we just let it rest there. I really don't see what value there is in continuing to discuss what none of us plans to do.
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