amp needed for a 15'' 1000watt sub?

[Jamo]

WTF? Class Ds don't make the blindest bit of difference so long as you use them where they're designed to be used - Sub-bass. Class AB amps are typically suited to fullrange and components as they do have better clarity through a larger range, but for Sub-bass this is pretty much wasted. Also, typically Class AB amplifiers are less efficient than Class D amplifiers, so you'll put more load on your (10+ year old) alternator for the same effective power and output. And significantly more expensive Watt-for-Watt...

However if you want something to take your car apart, I've got a JL 13W7 and a Solid Audio 2500D which should be more than capable. For sale too!

*Edit - This is for a typical car audio system. For SQL, yes, you would probably specify an AB but this would A) cost a fortune and B) require a massive amount of experience to design the enclosure/set up crossovers and also set the soundstage up properly, which IMO the Coupe is a bad shape for sound stage.

Each to their own I 've had both and know the difference instantly used to do weekend installs for bassbin

I run an genesis AB with a JL W6v2 couldn't stand the sound with a class D amp.

How much is the JL13W7?

[mark_s2]

Just a quick post to clear up the amplifier classes:

Class A
The current in the output stage conducts throughout the entire cycle which makes it the most inefficient designs of all classes. Class A amps can be as little as 15% efficient and produce massive amounts of heat as the output devices are biased to conduct continuously. Doubt it would ever be used in car audio though I may be wrong.

Class AB designs are the most widely used for audio applications. In Class AB designs the the two active elements conduct more than half of the time to reduce the cross over distortions that are produced in a pure Class B design. Class AB are typically around 50% efficient.

Class G amplifiers switch the supply rails as the signal output for each rail is approached. It is effectively a more efficient version of the class AB

Class D switches the output devices either fully on or off to achieve very high efficiencies. The analog output is created by modulation. The big advantage is the much smaller output devices, heat sinks & power supplies requried – hence they are cheaper to make.

Mark

[ericd]

no mention of pulse generators

[Fat Audi 80]

I agree with Mike and Mark;

IMHO, you will be fine with a class D on sub bass. It is only working low frequencies and would be better value for money....

HTH

Cheers,

Steve.

[Rusty]

I might sell my Kenwood PS401M, no idea what class it is but it's a beast!

[Jamo]

heh you can tell this aint talkaudio or guys into competition systems

[Rusty]

Nah. I used to like audio stuff but then I realised it weighed lots so now I'm trying to sort an install in the front doors to suit my needs...

[MikeLarwood]

heh you can tell this aint talkaudio or guys into competition systems

Used to, but then got bored. It's not really my bag - I wouldn't do it to a car that I'd bought for it's performance, and I won't do it to a car I bought for fuel economy as the excess weight kills any fuel economy.

The W7 was £900 new, plus £300 for the dual slot-ported enclosure. Amp was £450 second hand (but used for around an hour).

Really, I think you're experiencing placebo effect if anything... Having used both for my subs in the past, it takes a lot of volume to be able to spot the difference between the two - and that could purely be down to the level of components used in the amplifiers as has been said, Class D are cheaper to make, so people make them cheaper (if you get what I mean!).

From the point of view of a 250w RMS sub like that, I'd hazard a guess that no matter what amp feeds what sort of signal as long as it pumps 250w RMS, it'll be quality of the sub that lets it down before the quality of the amp.

Back on topic - aim for around 350w@14.4. Should give you plenty at an actual of around 13v.

[bazookachicken]

Just a quick point as nobody has mentioned it yet but Class AB or D amps aside...
Unless you want the sub to sound muddy and flat you need to do some homework on enclosure size. The speaker manufacturers website should be able to provide you with the correct internal volume for the enclosure which will probably be bigger than you think with a 15" sub but it is vital to get it right if you want the system to sound any good regardless of amp. Too small an enclosure and it will strangle the travel of the cone also remember to port the enclosure (info on what size port should also be available from the manufacturer) or the pressure inside the enclosure will be massive and you run the risk of tearing the cone away from it's mountings.

Bass is my thing really I've played bass in a semi professional band for about 15 years and being a big gear junkie I've tried just about everything going in the pursuit of "that" sound.
A 15" speaker will give you some serious low end but most of the time a pair of 10" speakers will give you more bass and a much tighter sound as they have a quicker response.

It is a common missconception that for more bass you need a bigger speaker where as what you are generally looking for is a higher SPL (Sound Pressure Level). Bass is a strange thing it takes a significantly more powerful amp to produce the same db level for bass as it does for mid range, eg my bass amp is 1600watts RMS and our guitarists 100watt RMS amp is more than a match for it.
For a good bass sound you need to be able to feel it, and generally to create a higher SPL you need more speakers pushing air faster.
Most people in the music industry have pretty much dropped larger speakers in favour of larger numbers of smaller speakers in properly tuned enclosures.

Next time you go to a big concert notice that instead of massive piles of speakers either side of the stage you now tend to get drops of 10 or 15 modules with 2 or 4 either 10" or even 8" speakers in them and they produce as much if not more bass than the huge old rigs.

It depends what type of music you listen to but unless you need something to listen to test CD's at 20Hz or lower on (Not much real music gets anywhere near that low) you don't need a 15" sub in a car it'll just sound a bit dissapointing compared to the shear punch and clarity you can get from 10's.

Just some food for thought

[ericd]

I've broken some cones in my time, just not in a car ,


.....
Bass is my thing really I've played bass in a semi professional band for about 15 years and being a big gear junkie I've tried just about everything going in the pursuit of "that" sound.
A 15" speaker will give you some serious low end but most of the time a pair of 10" speakers will give you more bass and a much tighter sound as they have a quicker response.

[B]10" commonly fail at the surround cone interface, 15" typically don't ,

.....
It is a common missconception that for more bass you need a bigger speaker where as what you are generally looking for is a higher SPL (Sound Pressure Level). Bass is a strange thing it takes a significantly more powerful amp to produce the same db level for bass as it does for mid range, eg my bass amp is 1600watts RMS and our guitarists 100watt RMS amp is more than a match for it.

sound like an Ampeg ? you're lucky if you're getting 900 Rms continuous, irrespective of your cabinet loading

[bazookachicken]

"sound like an Ampeg ? you're lucky if you're getting 900 Rms continuous, irrespective of your cabinet loading"
Indeed it is Ampeg in places I'm basically running a Pearce BC-1 preamp into a Fractal Audio Axe FX and then into an old Ampeg SVP1600 poweramp and an Ampeg 8x10.
I know what you mean you'll never see the actual rated output from the amp but for arguments sake it is easier to quote the stock figures.
Do you play at all??
I'm actually looking to drop the poweramp and the cab from my setup now I have the Axe FX and run straight into the desk (only been on the waiting list 18months for it!!)
Should save some wear on the old avant and my poor back!!!

[M_GORDON]

A JBL sub is not that fussy so anything that can delivery 250 rms will do.

Is the sub single or dual coil?

Will make a difference as you'd want a 2 ohm stable amp on a dual coil sub.

I use a genesis profile sub amp very clean and does 550 rms and this is what I would recommend or a JL 500/1

Do not buy a class D amp, buy a class AB

Class D amps give big power ratings but sound rubbish.

jajajaja it´s very correct!

PS: 15" sub is very big, "demasiado". Better one god 12"