Benefits of a class D for subwoofer

[TinleyJake 10+ year member]

What are the benefits in using a class D monoblock for a subwoofer over a bridged class AB 2-channel amplifier?

From what I have read, the class D is easier on your charging system. Is there any audible difference when talking about the sunwoofer?

The JL 250/1 is rated as a class D at 250w and the JL 300/2 is rated as a class AB at 300w bridged. If these amps were priced the same, wouldn't there be more bang for the buck with the 2-channel?

I appreciate any feedback you may have.

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[bass-aholic 10+ year member]

what the hells a sunwoofer?

 

[benchambers80]

Get the 2 channel, later you can upgrade and use it on some comps.

 

[benchambers80]

For that small amount of power, either will be like nothing on your electrical system.

 

[bass-aholic 10+ year member]

http://www.sunwoofer.nl/

ohhhhhhh

 

[bsean63 10+ year member]

when you mount the subwoofer on the sunroof, DUH

 

[skateboardkid 10+ year member]

taken from wiki "

In loudspeaker systems, the value of the damping factor between a particular loudspeaker and amplifier, describes the ability of the amplifier to control undesirable movement of the speaker cone near the resonant frequency of the speaker system. It is usually used in the context of low frequency driver behavior, and especially so in the case of electro-dynamic drivers which use a magnetic motor to generate the forces which move the diaphragm."

A high damping factor indicates that an amplifier will have greater control over the movement of the speaker cone, particularly in the bass region near the resonant frequency of the driver's mechanical resonance. However, the damping factor at any particular frequency will vary, since driver voice coils are complex impedances whose values vary with frequency. In addition, the electrical characteristics of every voice coil will change with temperature; high power levels will increase coil temperature and so resistance. And finally, passive crossovers (made of relatively large inductors, capacitors, and resistances) are between the amplifier and speaker drivers, and also affect the damping factor, again in a way that varies with frequency."

the 250/1 has

Damping Factor: >500 @ 4 ohm/50 Hz Input Range

300/2

Damping Factor: >200 @ 4 ohm per. ch./50 Hz

this is actually opposite of what I would expect from A/B amd compared to class D, maybe due to their highly regulated power supplies or some other electrical nature.

Also concerning efficiency

Despite the complexity involved, a properly designed class-D amplifier offers the following benefits:

Reduction in size and weight of the amplifier,

Reduced power waste as heat dissipation and hence smaller (or no) heatsinks,

Reduction in cost due to smaller heat sink and compact circuitry,

Very high power conversion efficiency, usually ≥ 90%.

The high efficiency of a class-D amplifier stems from the fact that the switching output stage is never operated in the active (or linear for bipolar junction transistors) region. Instead, the output devices are either ON or OFF - both states representing minimum power dissipation in the output devices. When the devices are ON, the current through them is maximum but the voltage across the devices is (ideally) zero and when the devices are OFF, the voltage across the devices is maximum but the current is zero. In both cases, the power dissipated (V x I) is zero. All these calculations are based on ideal circumstances. In practice, there are always losses, due to leakage, voltage drop, switching speed of power devices, etc. However, these are still small enough to keep efficiency very high.

taken from

http://en.wikipedia.org/wiki/Electronic_amplifier#Class_A

Like someone said if your get the 300/2 you can use it for comps later and get a class D AQ2200 for less than $400 when you want some real powa!.

 

[hemi=22s 10+ year member]

when you mount the subwoofer on the sunroof, DUH

rofl:laugh://content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif:laugh://content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif:laugh://content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

 

[helotaxi 5,000+ posts]

Damping factor is hugely unimportant. It's either high enough or not. Once it is above the threshold of "enough" more is not better.

If you're talking lower power applications, it really doesn't matter. For higher power apps, Class D is the way to go simply because is will only require a small nuke power plant to keep it fed as opposed to two large ones for a Class A/B amp of the same power output.

 

[TinleyJake 10+ year member]

Thanks for the quick informative feedback.

I'm just getting back in to car audio after a 15 year hiatus. I'm sure it wasn't, but car audio seemed way easier back then.

Thanks again

Back to the the sunwoofer enclosure...... **** where the hell's the spellcheck:verymad://content.invisioncic.com/y282845/emoticons/verymad.gif.3f39c5c2fd57527b671fad3efdfac756.gif:verymad:

 

[helotaxi 5,000+ posts]

If you read more on this forum, once you realize that the people posting are doing car stereo, it will become quickly apparent that car stereo is easier than it's ever been.

 

[hognutz 10+ year member]

The biggest benifit of class d to the consumer is cost and effecincy. Fewer components, smaller footprint, better effeciency can equal smaller heatsinks, etc. they are a switching amp which stores up power to use instead of burning it into the heatsink but switching can be noisy so you can get more distortion from a class d.

subwoofer draw more current than mids and highs. so most run a less effecient class a/b there because it has less distortion and then use a D class for low frequency.

so you charging system and wallet like you better. A true audiofile may choose to run class a/b all around.

 

[helotaxi 5,000+ posts]

Modern Class D amps can have distortion figures just as low as A/B. For the record, Class D amps don't store excess power, the merely draw what they need to produce the power that they're asked to. The difference is that there is less waste all around with the Class D design.

Cool thing about Class D is that the efficiency doesn't change with power output. With a Class A/B design you might get 70% (being generous) at full output. Chances are though that the amp will actually draw MORE current at a lower output level because the efficiency drops with the power level. At 33% of output, most A/B amps have their worst efficiency. Since this is the real output level thatyou use in daily listening, this is important. For a Class D, the current draw is pretty linear all the way through the power range so at 1/3 power its drawing about 1/3 of the current that it would at max power.

 

[ccotenj 10+ year member]

If you read more on this forum, once you realize that the people posting are doing car stereo, it will become quickly apparent that car stereo is easier than it's ever been.

now that amused me... //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

sadly enough, it's correct...

 

[Symon_say 10+ year member]

what the hells a sunwoofer?

A green woofer, it works with sun energy so you dont need an amp.