Originally Posted by
EarmarkMarine
Brian,
The thread got derailed specifically in post #17. Prior to that, opinions flowed freely without reprisal. Mike Mandley specifically called out the posts of two other members, MLA and myself. But when opinions differed from one brand's agenda, he felt threatened and compelled to address that. He could have given his own opinion without referencing or contradicting the posts of others. That is precisely what triggers these exchanges. The other action that typically triggers these exchanges, certainly in my case, is when one manufacturer comments on another manufacturers products or targets the lead dog to build his own brand awareness. The veiled digs can be so obvious and transparent. Just look at post #27 that is loaded with digs to alternate products and technologies.
Now you come on here and do exactly the same. You criticize the technical nature and content of other posts then go on your own technical rant....that by the way has no substance....just random bits of info.
I stated from the beginning that there are different levels of quality within all topologies. It is in print beforehand. Also, don't dispute things without offering a specific fact. I have supporting facts if you want to question something specific beyond a general criticism. Like for instance, Prosound. My coworker, Odin, has done live acoustic engineering for years in the evenings and weekends. He also plays in a successful band. My son has a degree in acoustic enginnering, has his own studio and works in the live sound equipment industry. I'm exposed to a lot.
Now what is particularly misleading is that Class D amplifiers lose efficiency at lower impedances. Is that true? Asolutely! As an example, they can drop from 84 percent efficiency at 4-ohms to 71 perecent efficiency at 2-ohms. However, what wasn't mentioned is that Class AB drops from an inherently low efficiency in the same way as the impedance drops. In fact, since the bias applied to Class AB amplifiers is constant, they can dip down to 20 percent efficiency at very low output power levels. So please share the entire story rather than placing a self-serving spin on it.
We have the luxury of electronics switchers. I would like a few local Dallas members to do a blindfold test between a good Class AB and a good Class D amplifier to see if they can detect which is which. If the novice cannot hear a difference on far superior speakers than you will ever find in a boat, then we should be able to put this to rest. So step up and accept that challenge please. You hand pick the blindfolded guys and I'll videotape the results. I'm excited!
Which Class D amplifiers knock out reception in cars? I know of some Class AB and H amplifiers that do knock out reception. Class D and Class AB often share the same type pulse width power supplies. Old school Class D amplifiers from a decade ago? Sure. Today with any of the brands that I am familiar with? Absolutely not. Man, that's just plain deceptive.
Class D stabilty issues at low imedances? Yeah, the Infinity amplifiers from a decade ago liked one narrow impedance range. The Exile Class D monoblocks are rated to 1-ohm. Again, those kind of statements are just plain deceptive to the core. Just designed to cast doubt.
Now let's start a new thread about authentic power specs. Who provides them and who does not.
David