HU Question

[koonjiun]

Dear all forummers,
what's the difference between 3 RCA preouts and 1 RCA preouts? what does it do?

and what specs should be considered for a good quality HU?

thanks in advance

 

[appleyard]

simple.
1 RCA is where the HU allows you to connect to 1 amp. But if you wish to connect 2 amp you have to use spliter or y cables.

3 RCA means you an connect to 3 amps. Usually its 1 output for sub amp, and 2 for components (usually front and rear).

I refer good HU to be high quality internals and lots of tuning functions and options. I remember back then when i was so impressed with the motorized faceplate. i got one without considering other features. But when i finally got one i just dont care.

 

[cacin]

the 3 rca pre-out means it has 3 pair of rca pre-out. Normally it would be for front, rear and sub. the one RCA would be either for sub or front. This would be connected to your amp if your amp does not accept high level input.

 

[koonjiun]

thanks for the reply.

is there any drawback/disadvantage of

1 RCA ---> splitter/y cables ---> 2 amps

comparing with

using 2 RCA ----> directly to 2 amp


thankiu thankiu in advance

 

[appleyard]

definitely
by having 2 rca output you can have a sub output and soeaker output. You can tune and control your sub from your HU.

By using y cables you risk of adding noise you your system.

 

[koonjiun]

SQ and SPL

off topic a bit..

what is SQ and SPL?
difference?

 

[howiechoo]

definitely
by having 2 rca output you can have a sub output and soeaker output. You can tune and control your sub from your HU.

By using y cables you risk of adding noise you your system.

but the percentage of noise create by splitter is 0.01 percent...
only not pro installer will blame the splitter create noise with the fact that they didn installing well....

 

[ahchun]

hi all
wanna ask what is high level input? is it mean from HU direct take the output to speaker wire and connect to amp high level input port or mean other?

 

[oldskolboyz]

hi all
1) wanna ask what is high level input?
2) is it mean from HU direct take the output to speaker wire and connect to amp high level input port or mean other?

1) High level input = same as converter.. some amp have built-in coverter.. to convert high level signal to low level signal.. How to know high level signal ? Normally we refer to speaker cable out from HU, NOT THE RCA OUTPUT.. Why? coz the signal transmited direct from HU speaker cable out has been amplified with built-in pre-amp..this we can refer to HU itself, some have 50w X 4, 45w X 4 or 60w X 4.. in this case we need converter to naturalized it back to low level signal.. To confirm it, U can check your amp.. RCA terminal will mark or write as Low Level Input.. Low Level Input doesnt mean for SUB input..

2) Yes correct.. using speaker cable not RCA cable

 

[Zenn]

Dear all forummers,
what's the difference between 3 RCA preouts and 1 RCA preouts? what does it do?

and what specs should be considered for a good quality HU?

thanks in advance

usually better HU have more pre outs (3 pre out HU usually better than 1 pre out HU, more expensive also). using Y-cable doesnt induce noise to the system, just that it reduces the quality of signal from HU to amp (since its divided by 2 already). having more pre outs gives u more flexibility in system setup, tuning, etc. also pre outs with higher voltage will give u stronger signal to the amps and less chance of noise disturbing the signal quality.

good quality HU are measured with its reputation and review by users, not usually by specs. of coz u can still use specs as a measure, but many manufacturers have access to the same items and some will exaggerate for marketing purposes.

 

[ahchun]

oldskolboyz,

Thanks for the info.

 

[acidcoller]

i have a question here

The 3 way electronic crossover is still can use or important if use HU 3 RCA preout???

 

[oldskolboyz]

i have a question here

The 3 way electronic crossover is still can use or important if use HU 3 RCA preout???

Depend on your systems, I just refer to Full Active Set-up which mean BANDPASS very important.. Not all HU built-in XO c/w 3set pre-out capable to do BandPass signal even DVD HU have built-in 5.1 DTS/Pro Logic & etc decoder also dont have. In full active set-up the critical moment is MidWoofer/Midbass/MidRange need BandPass signal/level with consist of HighPass (beginning Freq cut off point) & LowPass (ending Freq cut off point).. let say U want your Mid only play 50hz to 4Khz freq.. in this case U need HighPass to cut freq below 50hz & LowPass to cut freq above 4Khz.. for me is usefull... btw not all 3way in the market is truely 3way XO.. alot kencing XO 1... U can check this XO Macrom 48.13, Orion CS1, Tru F1 or F2, xetec and compare with lanzar X8 or X6.. sure U can see the difference

 

[acidcoller]

wah...
very hard to finding true 3 way lor...
hurm...

so dat mean not use 3 way if the HU has 3 RCA preout??

so must use 3 RCA cable to setup to amp 2 RCA cable for 4 chanel (componenet rear n front) n 1RCA cable to 2 Chanel(subwoffer)???

If i use 2 RCA cable only 1RCA for 4 chanel n 1 RCA for 2 chanel can ka???

 

[Zenn]

i have a question here

The 3 way electronic crossover is still can use or important if use HU 3 RCA preout???

minimum 1 rca is all u need if u have a 3way electronic crossover. depends on how many inputs the elec. xover has, then u can use how many pre outs from the HU.

not all HU with 3 rca pre outs can do a 3 way crossover for active setup (high, mid,low) bcoz they usually have a 2 way electronic crossover (front, rear, sub) but also using all 3 pre outs. the difference is that the mid pre out must be in bandpass mode (it has both highpass & lowpass filters), for tweeter u just need highpass (make sure frequency is in khz not Hz) and for sub u just need lowpass filter.

 

[Zenn]

If i use 2 RCA cable only 1RCA for 4 chanel n 1 RCA for 2 chanel can ka???

can also if the amp can accept single input for all 4 channels and then depends on the inbuilt HP/LP filter specs of the amp itlsef...