Moble Enclosurs
10+ year member
Box Designer/Builder
The HU has a preamp voltage between 2-9V normally, but this is not the voltage that is of concentration because it is merely amplified. The voltage from the amplifier to the "load" or subwoofer(s) is the voltage that needs to be matched, as well as resistance as close as possible without going below the minimum resistance of the amplifier. BUT, here is why some people get away with using say, 1Ohm on an amp that is rated for a min of 2Ohms......this is why sometimes you might not get damage.....because at the 1Ohm resistance, you only require a portion of the voltage to and from the sub(s) to get the same output, so as long as the portioned voltage/amperes are not exceeded, an amp rated for 2Ohms (for example) can essentially run a 1Ohm load at the max of the portioned voltage, but this is always not recommended. This happens when people think they are running more power than they really are, and say, "Well, Ive done it and I was fine". There is an electrcial reasoning of why it worked. Again, never recommended though because when songs are playing, this voltage may be exceeded without notice. THAT is why damage can occur by wiring for a lower load resistance than an amplifier. The amp will rely on amperes as the driving force of the output, so if the load requires more than the amp can handle, it will hurt the amp. But when the amps are not exceeded, usually the voltage will hold if resistance is constant. Considering that resistance is not constant (electrically), then it is not worth the chance.
So, HU output voltage is only important if you plan to use the speaker level outputs, and not the preamps. Then you will want to know the resistance of the HU and power levels, and then get voltage or vice versa, etc. And get the voltage of the speakers another way that will be shown in the video or another vid, and match the speakers capabilities with the HU within the non-distorted portion of the volume from the HU. It really can be a pissing match between each component in some cases and the fact that each step will or can affect each other, makes it something less explored by those who just want simplicity and jsut want to listen to the music already, lol. Not many will talk about what is really involved because it can get complicated or tiring to figure it all out, and in some cases may have you searching for the right gear for weeks before finding something that will match.
For instance, if using the HU speaker outputs, say you get them to play 15w of power on each line, and the resistance is 4Ohms (jsut an example). Then to find what speakers will be most efficient, first know not to exceed 4 Ohms min (like using a 2Ohm load). And figure for voltage that way, or if you have voltage, then you get power, which stated was 15W(true power-not rms or peak). Then find a speaker that will only require 15W to run it. usually if you get one that is 70% of rms, that will be ok. So, if the speaker is 50Wrms, then true will be around 35W@4Ohms, and will handle the HU fine. But getting this true power can take a lot of work as well. And sometimes not enough information is given to find true power from a speaker. They only give peak or rms or both. SO, I always say if you are limited, use 70% of rms and if peak is shown, use 70% of half of peak. This will be as good as you gan get to true power as possible without knowing how to obtain acoustical power and such with all of the specifications, which would take a LOT to explain. This is a general idea of what you can do to match the speaker to the HU that way. But not quite accurate, just acceptable.
I had bought a speaker for testing that says it put out 50WRMS and I tested it to only handle about 10W at xmech! Quite a difference, but portions are used because it is better to have more power/less required power than more required power that is not available.
I hope that helps a bit more.
So, HU output voltage is only important if you plan to use the speaker level outputs, and not the preamps. Then you will want to know the resistance of the HU and power levels, and then get voltage or vice versa, etc. And get the voltage of the speakers another way that will be shown in the video or another vid, and match the speakers capabilities with the HU within the non-distorted portion of the volume from the HU. It really can be a pissing match between each component in some cases and the fact that each step will or can affect each other, makes it something less explored by those who just want simplicity and jsut want to listen to the music already, lol. Not many will talk about what is really involved because it can get complicated or tiring to figure it all out, and in some cases may have you searching for the right gear for weeks before finding something that will match.
For instance, if using the HU speaker outputs, say you get them to play 15w of power on each line, and the resistance is 4Ohms (jsut an example). Then to find what speakers will be most efficient, first know not to exceed 4 Ohms min (like using a 2Ohm load). And figure for voltage that way, or if you have voltage, then you get power, which stated was 15W(true power-not rms or peak). Then find a speaker that will only require 15W to run it. usually if you get one that is 70% of rms, that will be ok. So, if the speaker is 50Wrms, then true will be around 35W@4Ohms, and will handle the HU fine. But getting this true power can take a lot of work as well. And sometimes not enough information is given to find true power from a speaker. They only give peak or rms or both. SO, I always say if you are limited, use 70% of rms and if peak is shown, use 70% of half of peak. This will be as good as you gan get to true power as possible without knowing how to obtain acoustical power and such with all of the specifications, which would take a LOT to explain. This is a general idea of what you can do to match the speaker to the HU that way. But not quite accurate, just acceptable.
I had bought a speaker for testing that says it put out 50WRMS and I tested it to only handle about 10W at xmech! Quite a difference, but portions are used because it is better to have more power/less required power than more required power that is not available.
I hope that helps a bit more.
