Ok... I'm kind of confused on this....
Since my head unit (Alpine 9835) has a 26w x 4 rms (I'm assuming it's class A/B) does that mean it's only running my speakers at ~13-16w since A/B is around 50-60% efficient?
If I were to get a 4 channel A/B amp, would I have to get one that has a 100-125w (50-60%) rms per channel to get the max out of my speakers (they have a 50w rms)?
Replies (6)
ttocs on 11/16/2004 01:52:54
less then that. Deck pwr is rated in max pwr, so really you are getting 13 watts rms.
uochronos on 11/16/2004 02:46:04
i think are friend is a bit confused here ttocs. A/B amps are 50-60% effiecent this does not mean they only give 50-60% of there RMS power.
i dont know what exactly you know so i well start basic. wattage is simple. Amp X voltage = wattage so lets say your amp is 500watts class D mono noe thats 500watts we know of now lets say your car runs at 13volts constant. so 500watts divided by 13 volts = 39amps so now we know it takes a minimu of 39amps to get 500watts. however class d are only 90% efficient so 10% of the amps going in are turned into heat not sound. so it take that amp 10% more then 39amps to reach 500watts. so that amp would pull something like 45amps at full power....
got me so far?
now a A/B 500watt amp is only 60% efficient so it would take 40% more amps to reach 500watts so this amp would pull upwards of 50-60amps
hopefully i didnt lose you and cleared this up a bit.
any question please ask.
Chronos
P0werLifter on 11/16/2004 03:45:56
Heres a little more math to maybe help you out to understand it all. Lets stick with the 500watt amplifier for this example. Since A/B amps run at 50-60% efficiency lets just do the math here.
500watts / .5 (efficiency factor of 50%) = 1000watts of input, to produce 500watts of output. Now Divide the 1000watts by your charging systems voltage (13.5 good ave number) 1000/13.5= 74amp draw for that class A/B amplifier.
Lets take the same 500watt amp, but make it a Class D. Class D amps run at >90% efficient as chronos has stated.
500/.9 (90% efficiency)= 555watts of input, to produce the 500watts of output. 555/13.5 =41.15 ampere draw for the class D.
And Now,,,i Just realized you werent even comparing the two HAHA, but at least you can see the difference in both types.
Now as far as your question, Get an amplifier that will run >50watts RMS or more per channel to run those speakers. When we talk about efficiency were talking about good the amplifier is as using the engergy it recieves and converting it to usable power.
Hope this helps yah
swez on 11/16/2004 08:41:30
That HU uses a special V-Drive technology that actually boosts input voltage to create higher output power from the internal amplifiers. It's notably different from other HU models that do not employ this type of power supply technology. It will deliver what it says... 26 RMS @ 4 ohms x 4 channels. (60 x 4 peak watts)
Note the #10 wire needs for this HU. That means it does pull some serious power from the electrical system, to produce the rated output. Yes, these are Class A/B amplifiers in this HU.
Your speakers are 50 watts RMS. They are now getting 50% of their rated power. (50 WRMS) If we doubled the power to a given speaker, we get ~+3dB more SPL per speaker. Depending on the actual efficiency rating of the speakers used, you could easily reach 100 dB inside the cabin with efficient speakers and this HU.
If you wanted more SPL from these speakers, you can add an outboard 50 x 4 amp. (RMS) This will increase your overall SPL in the cabin by +3 dB per speaker.
Remember, we are talking RMS power here... NOT PEAK. It is also CEA -2006 compliant. That means 14.4 volts input and <1% THD., at rated power output.
Hope that helps,
Swez
Swez
aposynthesi on 11/16/2004 20:00:18
So what everyone is saying is a 700w class a/b can put out 700w rms, but it would require 1400w to do so (800w being 1600, 900 being 1800, etc...)?
I believe the speakers have ~150-200w peak... and the HU peaks at 60w per channel.
The sub amp specs are as follows:
· Class "AB" Circuitry
· Audiophile Grade Components
· Qsink Technology (Heat Management System)
· High Efficiency Mosfet Outputs
· On-Board (Fully Variable) Low Pass X-over
· Enhanced Dynamic Performance
· Mono Output
· 2 Ohms Mono Capability
· Bandwidth 20 - 28KHz
· X-over Slope 12dB
· 12dB Bass Boost @45 HZ
· Input Sensitivity 285MV-4.3V
· Input Voltage 11-14.4 Volts
· Signal To Noise Ratio >95dB
· THD At Rated Power < 0.05%
uochronos on 11/16/2004 22:23:08
yep thats is a basic way of looking at it. it well take almost twice the the input wattage fronm your alternator to get the RMS output wattage to the speaker.
Chronos
Since my head unit (Alpine 9835) has a 26w x 4 rms (I'm assuming it's class A/B) does that mean it's only running my speakers at ~13-16w since A/B is around 50-60% efficient?
If I were to get a 4 channel A/B amp, would I have to get one that has a 100-125w (50-60%) rms per channel to get the max out of my speakers (they have a 50w rms)?
Replies (6)
ttocs on 11/16/2004 01:52:54
less then that. Deck pwr is rated in max pwr, so really you are getting 13 watts rms.
uochronos on 11/16/2004 02:46:04
i think are friend is a bit confused here ttocs. A/B amps are 50-60% effiecent this does not mean they only give 50-60% of there RMS power.
i dont know what exactly you know so i well start basic. wattage is simple. Amp X voltage = wattage so lets say your amp is 500watts class D mono noe thats 500watts we know of now lets say your car runs at 13volts constant. so 500watts divided by 13 volts = 39amps so now we know it takes a minimu of 39amps to get 500watts. however class d are only 90% efficient so 10% of the amps going in are turned into heat not sound. so it take that amp 10% more then 39amps to reach 500watts. so that amp would pull something like 45amps at full power....
got me so far?
now a A/B 500watt amp is only 60% efficient so it would take 40% more amps to reach 500watts so this amp would pull upwards of 50-60amps
hopefully i didnt lose you and cleared this up a bit.
any question please ask.
Chronos
P0werLifter on 11/16/2004 03:45:56
Heres a little more math to maybe help you out to understand it all. Lets stick with the 500watt amplifier for this example. Since A/B amps run at 50-60% efficiency lets just do the math here.
500watts / .5 (efficiency factor of 50%) = 1000watts of input, to produce 500watts of output. Now Divide the 1000watts by your charging systems voltage (13.5 good ave number) 1000/13.5= 74amp draw for that class A/B amplifier.
Lets take the same 500watt amp, but make it a Class D. Class D amps run at >90% efficient as chronos has stated.
500/.9 (90% efficiency)= 555watts of input, to produce the 500watts of output. 555/13.5 =41.15 ampere draw for the class D.
And Now,,,i Just realized you werent even comparing the two HAHA, but at least you can see the difference in both types.
Now as far as your question, Get an amplifier that will run >50watts RMS or more per channel to run those speakers. When we talk about efficiency were talking about good the amplifier is as using the engergy it recieves and converting it to usable power.
Hope this helps yah
swez on 11/16/2004 08:41:30
That HU uses a special V-Drive technology that actually boosts input voltage to create higher output power from the internal amplifiers. It's notably different from other HU models that do not employ this type of power supply technology. It will deliver what it says... 26 RMS @ 4 ohms x 4 channels. (60 x 4 peak watts)
Note the #10 wire needs for this HU. That means it does pull some serious power from the electrical system, to produce the rated output. Yes, these are Class A/B amplifiers in this HU.
Your speakers are 50 watts RMS. They are now getting 50% of their rated power. (50 WRMS) If we doubled the power to a given speaker, we get ~+3dB more SPL per speaker. Depending on the actual efficiency rating of the speakers used, you could easily reach 100 dB inside the cabin with efficient speakers and this HU.
If you wanted more SPL from these speakers, you can add an outboard 50 x 4 amp. (RMS) This will increase your overall SPL in the cabin by +3 dB per speaker.
Remember, we are talking RMS power here... NOT PEAK. It is also CEA -2006 compliant. That means 14.4 volts input and <1% THD., at rated power output.
Hope that helps,
Swez
Swez
aposynthesi on 11/16/2004 20:00:18
So what everyone is saying is a 700w class a/b can put out 700w rms, but it would require 1400w to do so (800w being 1600, 900 being 1800, etc...)?
I believe the speakers have ~150-200w peak... and the HU peaks at 60w per channel.
The sub amp specs are as follows:
· Class "AB" Circuitry
· Audiophile Grade Components
· Qsink Technology (Heat Management System)
· High Efficiency Mosfet Outputs
· On-Board (Fully Variable) Low Pass X-over
· Enhanced Dynamic Performance
· Mono Output
· 2 Ohms Mono Capability
· Bandwidth 20 - 28KHz
· X-over Slope 12dB
· 12dB Bass Boost @45 HZ
· Input Sensitivity 285MV-4.3V
· Input Voltage 11-14.4 Volts
· Signal To Noise Ratio >95dB
· THD At Rated Power < 0.05%
uochronos on 11/16/2004 22:23:08
yep thats is a basic way of looking at it. it well take almost twice the the input wattage fronm your alternator to get the RMS output wattage to the speaker.
Chronos
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