Class A/B or D amplifier for full range speakers?

[David Analog]

For example, a JL Audio M series amplifier will typically produce its 14.4V rated power with a much lower 12.6V supply, as repeatedly demonstrated in tests. And it will typically produce at minimum 95% of the 1kHz rated power across the entire audio bandwidth, say down to 40 Hz. You can bet that the Fusion HU, or any HU, will not come close to exhibiting the same behaviors. So even at the identical 1 kHz power rating, these two amplifiers could sound significantly different. 1 kHz power isn't at all revealing. Why? Because past a point, for every one octave lower, it will require four times the power to produce an equal amplitude, and because 50% of all music fundamentals fall between 200 and 600 Hz, and because the mid bass and deep bass that register even lower are extremely demanding of power by comparison. The power needs of music are not linear.
Moving on. Most amperage draw calculations are based on DC equations (simple volts X amps = watts). But amplifiers are not DC light bulbs. Music is very transient in nature and very different from a sine wave used in testing or DC. So music, unless pure drone bass (which is noise) draws a mere fraction of the current.
I guess what I'm saying is that to rely on specs is to understand every qualification and exclusion. Specs are just a unit of measurement for the sake of the most basic of comparisons but do not necessarily translate to music and real world usage.

Btw, a side note. A fridge is by far the least efficient when ramping up to cool down. So if possible pre-cool the fridge and contents while the boat is still connected to AC and a healthy battery charger (keeping in mind that small chargers are not intended to do a power supply duty). Pre-cool all contents at home or in the hotel/motel. You can also get a head start by throwing in a couple of those freezer packs. Once cooled, temperature maintenance requires far less energy. Then simply practice the phrase, "born in a barn?"

 

[Bruce]

Btw, a side note. A fridge is by far the least efficient when ramping up to cool down. So if possible pre-cool the fridge and contents while the boat is still connected to AC and a healthy battery charger (keeping in mind that small chargers are not intended to do a power supply duty). Pre-cool all contents at home or in the hotel/motel. You can also get a head start by throwing in a couple of those freezer packs. Once cooled, temperature maintenance requires far less energy. Then simply practice the phrase, "born in a barn?"

The fridge had been running all boating season long for three years. Generally we place precooled items into the fridge.

A Guest 2610A onboard charger keeps the batteries charged when shore power is available.

This is My Unusual (Alternate) Dual Battery Setup

 

[Mainah]

The fridge had been running all boating season long for three years. Generally we place precooled items into the fridge.

A Guest 2610A onboard charger keeps the batteries charged when shore power is available.

This is My Unusual (Alternate) Dual Battery Setup

The link to your battery setup appears to be broken. I am getting interested because I just made the decision to swap from dry stack to wet slip with shore power and water . I am starting to rethink my custom submerged wort style kegerator and cooler ideas and considering a more traditional compressor based drawer or cooler style fridge. Carrying a cooler to and from the boat every time has gotten old.

 

[Bruce]

@Mainah, I fixed the link. Moral of the story is not to drag and drop search results and expect them to work.

Here is the full URL - https://jetboaters.net/threads/my-unusual-alternate-dual-battery-setup.5632/

We love the fridge and would add it to any future purchase that did not already have one.

This is the fridge install thread https://jetboaters.net/threads/installing-dometic-waeco-cd-030dcw-refrigerator-in-yamaha-sx230.2630/

 

[viggen]

As stated class D tech in a amp can be great, it's not really A/B vs D but more about space/room available, power available etc. For home or car audio there are great A/B and D amps.... just like there are some crappy A/B and D amps

Comparing a amp that's 80-90%+ effecient vs something that's probably 40-50% effecient in a environment where the engine will not be run for a long time D seems like a easy choice. Plus there do not seem to be many if any A/B marine amps available as well....

Correct your fusion deck does state 26w at 4 ohms & 43w at 2 ohms however their manual doesn't state at what THD those numbers were acquired. For all we know those numbers could be at 10% THD or more thus quite a big difference between a seperate amp developing similar power.

I would bet fusion greatly exaggerated these specs and did not use CEA2006 standards for showing amps actual power, if they did they would of listed that rating. Thus they probably used a smaller frequency response and a higher THD to show a unrealistic power rating for the amp.

 

[David Analog]

Hope this helps. Let's not overlook the other industry power rating standards. Besides RMS and CEA2006, you also have WLS (When Lightning Strikes) and JBF (Just Before Fire).