Differences in SPL

[gunz4me 10+ year member]

From what I have seen on a test bench with a dummy load (and in the real world vehicle environment with a subwoofer) a mid level Class D amp will generally clip harder and faster than your mid level class AB amps. What I once thought was a difference in topology has been attributed to a bonehead in charge of setting the gains in 90% of the cases. The other 10% of the difference is due to the quality of the install with inadequate electrical to blame.

 

[djman37 5,000+ posts]

800 watts RMS is 800 watts RMS. How you get there is up to you.

Most of this discussion will center on issues OTHER than your question, that's the CA way.

to linkz, did TI buy the tripath or did tripath license it from TI? Those chip numbers look familiar.

 

[SPLaudio 5,000+ posts]

thd but more importantly is the dampening factor (control of subwoofer)...

 

[gunz4me 10+ year member]

thd but more importantly is the dampening factor (control of subwoofer)...

With the slowed down, chopped, distorted, hip-hop garbage that most of these pudknockers listen to, damping factor is the least of their concerns!

 

[cleansoundzz 10+ year member]

I listen to R&B, oldies and reggae. No current hip-hop. With that type of music, sq is much more important.

 

[newusername 10+ year member]

Will 800 watts in class A/B give me the same thump and spl as 800 watts in class D in my subs?

Not sure what you mean by "thump". If you're asking if a watt is a watt, then the answer is yes.

What's heavier? A pound of feathers or a pound of lead?

I think it would be wiser to argue which is more massive.

800 watts RMS is 800 watts RMS.

No such thing as watts RMS. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

thd but more importantly is the dampening factor (control of subwoofer)...

Nope. Damping factor (not dampening) hardly matters at all nowadays.

 

[gunz4me 10+ year member]

I listen to R&B, oldies and reggae. No current hip-hop. With that type of music, sq is much more important.

In that case go high end Class D OR middle to high end class AB. Of course, you could always go old school too //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Nope. Damping factor (not dampening) hardly matters at all nowadays.

I have to agree because most modern day subwoofers have a suspension on them that will make up for a lack of damping factor. This really holds true in most of the SPL subwoofers because they will generally be run at low impedance on a Class D. A Class D amp generally has a lower damping factor than a class AB amp due to the nature of the class D design. When running it at low impedance, I have seen some class D amps churn out a damping factor of 25 to 50. Also, what will this damping factor be after 10 feet of 8 to 16 gauge speaker wire? With a decent, modern day, quality subwoofer, I would venture to agree that damping factor isn't as important as it used to be.

 

[cleansoundzz 10+ year member]

I was going to use a PPI PCX 2200. Definitely old school and the PCX series from PPI is the last of the good amps from them before DEI took over and messed up the company.

 

[gunz4me 10+ year member]

fosgate uses class bd b for the sound output d the the power supply but with a 800 watt class ab you wont have enough time to tell if the output is the same because it will have over heated and gone into protect

Wow, what a genius you are! Explain this then Einstein:

That is a Class AB amp that will produce 800 watts RMS @ 4 ohms mono without overheating or going into protect. Of course, a Class D amp that produces 800 watts @ 1 ohm mono will look like a peanut next to it.

What about this amp:

It will produce 800 watts RMS @ 1 ohm mono. Actually, it will produce more on a decent electrical system, but that is another one that won't overheat and go into protect.

And last but not least, what about these amps:

After the high voltage modifications are complete, the blue one will do 850 watts RMS @ 8 ohms and the purple one will do 1,100 watts @ 8 ohms. Again class AB.

ETA: Did you ride a short yellow bus to school? Were you in "special" classes?

 

[squeak9798 5,000+ posts]

THe way it was explained to me is the nothing but a difference in efficiency reproducing a range of frequencies. a/b amps do better at high freq, d is better at low, regardless of wattage.

Class D has been able to operate acceptably over the entire audio bandwidth for quite some time.

And class A/B operate acceptably at low frequencies.

 

[cleansoundzz 10+ year member]

I had a chance this morning to swap out my 10 inch Kicker CVX's for my 10 inch Crossfire BMF's and my PPI PC 1800.2 (mono block) for my PCX 2200 (2 channel) and here are my observations. The 2 channel amp picked up more musical tones and the bass was not as muddled. There was better subwoofer control on my music when using the 2 channel amplifier. Not that the 2 channel is better than the mono block for bass, but it in my mind was clearly noticeable immediately. Secondly what surprised me the most was that my 10 inch Crossfire BMF's hit the lows much much better and had better bass response overall. Not a knock on Kicker but just an observation. I listen to r&b, reggae and oldies 99% of the time so the 2 channel seems to handle this music better. For rap, I think a 2 channel or mono block will be suitable. If a monoblock is used for music that isn't rap then running the amp at a 1 ohm load takes away from the sq of the bass.

When riding to work this morning and using the 2 channel for about 35 minutes it didn't get too warm and my lights didn't blink too much if any.

I want to thank you guys for your insights and comments about 2 channel, monoblocks and 800 watts because it worked out really well for me. One thing for sure is that you guys all know what you are talking about.

 

[gunz4me 10+ year member]

One of the common misnomers that most fail to recognize is that a Class D amp will draw just as many amps from the battery/alternator as most class ab amps. It may be a tad bit less when comparing 800 watt Class D to 800 watt Class AB, but a Class D will still **** down some juice at high volume. The efficiency part comes from what the Class D does with all that current that it is drinking at full tilt versus a Class AB amp. Also, at lower volumes, the switching power supply of the Class D allows it to draw less current than most Class AB amps.

Now, let me flip it.... A high voltage class AB amp, like the Linear Powers I posted above, can actually make more power while drawing less amperage from the alternator and battery than a Class D amplifier. I have a tiny little modified LP 150 in storage that produces 600 watts RMS @ 8 ohms mono off of 25 amps of fusing. The two amps above will produce 850 and 1100 watts RMS off of 60 amps of fusing @ 8 ohms mono. That kind of blows the whole "efficiency" thing of Class D out of the water, doesn't it? Regardless, I will take either one of those Linear Power 5002s @ 8 ohms over 99% of the 12 volt Class D amps that produce 1,000 watts RMS @ 2 ohms!

ETA: Most of the die hard old school audio nuts will agree that class AB sounds more musical on subwoofers than Class D. We also don't care to run our amplifiers @ 1 ohm mono either. Some of these young, whipper snappers just don't get it and never will

 

[cleansoundzz 10+ year member]

Running subwoofers at 1 ohm mono doesn't impress me and never has. I am being truthful with you when I say I can hear the difference distinctly between a class AB and class D on subwoofers. Others may disagree but thats on them. If I were in my twenties and early thirties I would use a class D no problem because I listened to more rap at that time. My musical preferences have changed quite a bit so a class D while great technology may not suit me anymore. I like class D don't get me wrong but I like class A/B for a more wide range of music.

 

[Linkz 10+ year member]

800 watts RMS is 800 watts RMS. How you get there is up to you.Most of this discussion will center on issues OTHER than your question, that's the CA way.

to linkz, did TI buy the tripath or did tripath license it from TI? Those chip numbers look familiar.

I'm leaning more towards TI licensing it. But, I'm not entirely sure about it.

 

[Diplexers 10+ year member]

I love my amp.//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif