hi all,

target:

higher entry level audio setup for personal listening experience, emphasis on balanced SQ

my proposed setup:

HU:
alpine hu with 2 4v preouts (1 for 2ch amp for speakers, 1 for amp and subs later upgrade)

Amp:

JL Audio XD200 200W 2 channel class d amp (better power efficiency so less load on kelisa 55amp alternator)

or

Zapco i250 250W 2 channel class ab

Speakers:

Aulux 7" speakers
Dynaudio md dome tweeters

my question is:

- is there any noticeable difference between 2v and 4v preouts? for small rooms like in kelisa?
- would the above setup good enough for entry level SQ without drawing too much power from the alternator?
- i have read that 40% of alternator amp is used to power electrical components in car at full load (aircond, lights etc). is this true?

any experienced sifu can guide me on this matter?

your questions:
-the general idea is that (from quick googling too):

sauce: http://www.diymobileaudio.com/forum/diyma-...-4v-preout.html


sauce: http://community.crutchfield.com/forums/p/21077/244965.aspx

- for most standard OEM alternators at the above rating, it is more than enough (assuming big3 upgrades are all done, proper grounding etc) especially if you're going for SQ setup and not SPL

- for kelisa, considering it isnt your avg recent cars with a lot of high tech gadgets, the load probably won't be as high as you think. 40% should be the correct % though other sifu thats more experienced (especially with this particular car) can answer better/corect me.

oh and for the aulux speakers:
http://forum.lowyat.net/topic/691232

you setting up your ICE at KK Lau?

also i've sent you a pm on some other questions, care to take a look at your pm box please?

hey thanks for that. it really clears things up for me. i plan on using class d amp and ive read it is prone to distortion despite good power efficiency, would 4v worth investing then?

how do we know 2V is able to drive one particular amp? is there any rule of thumb?

what is POS?

ive done big 3 upgrade btw

im buying stuff on my own and will get a shop to install it, the aulux speakers were from my previous car and i got it installed at kklau. i know quality to price ratio is really good with aulux

but i didn get ur pm bro. mind sending it again?

if you're already getting a 4v HU then why not? it is expensive, but what you pay is what you get.

and no, generally there isnt much rule of thumb unless you play your music really REALLY loud and you require high gain from your amp to sustain, and when it starts having distortions due to the gain/high volume, thats where its no good. else its fine, regardless of 2v or 4v.

and POS = piece of shit, very general acronym

and resent the pm
(was previously sent on 6 Feb)

pre-out voltage is critical to any amplification. the higher the better as amp gain do not need to be set high.
gain setting needs to be matched in order to prevent clip signal being sent. clip signal will burnt speaker voice coil

most HU will says its a 4V or even 8V(eclipse) preout, but in actual fact u wont even get close to 4V/8V. their 4V/8Vmeasurement is based on no load, meaning RCA not connected to amp. once u have a load, the measurement is very different, much much lower.

also in order to achieve their advertised preout, max volume + bass boost must be turn on.
who listen at max volume with max bass boost?

some people will say NO diff, but in reality they are the biggest difference.

another biggest issue to look at on the HU, is the output impedance. most HU dont print these on their specs sheet.

note: sometimes u hear people say this amp damn powerful but its only rated 50W RMS.
reason being the amp starts with a low amp gain sensitivity.
it can range from 0.2V onwards and some amps starts from 0.4V.
obviously the amp with 0.2V gain sensitivity will sound loud.