Im thinking of buying the components on ebay to save money and then taking them to an install shop to set it up.
What worries me are things like power/amperage of hu/amp and various speakers/sub that have to match more or less so that I dont end up with blown subs.etc

Can you recommend which specs to compare in HU/amps and speakers for a correct purchase.

 

How much do you want to spend, and how important is sound quality?

 

Electronics forum...

 

Well its not whether or not i wand a high-end unit or the cheapest possible.
I just need to find which specs to look for when buying components that match each other.
Say if head unit provides 18w RMS, 50W/channel what does that mean for an AMP, speaker, sub etc.
What Sub characteristics are affect by amps features, etc etc etc.

Let say if you were buying an entire a car audio system, how would you make sure that you dont endup with blown speakers/sub while using amps/head units power optimally.

 

electronics forum is your friend

 

Thanks for bringing this to me.

Now, HU power (the amp inside the hu) will NOT be used if you have an external amp, so don't pay attention to those numbers. Now, for speakers and subs, they come with RMS ratings. Those are ratings that tell you how much power the speaker can take to function SAFELY, efficiently, and at optimal quality. Now, the amp has an RMS rating at a certain OHM. Speakers are rated in OHMS. Power is doubled if OHMS are halved.


So, say you have a speaker that is 100 watts at 4ohms.

So, an amp (lets say class AB) that has 100watts at 4 ohms will have 200 watts at 2ohms. Get it?

So, IMHO, you should get an amp with 25% MORE power than the speaker needs, so the amp is not peaking in power, and doesn't heat up as much. Better for SQ, and healthier for the life of the amp. Also, when shopping for amps, make sure the OHMs match. Subs are generally available in a large variety of ohm combinations.

 

Its all personal opinion after a certain point. But if you want more directed answers....
dont lead into a question and leave the end etc. etc. etc.
We dont know what your asking.

If you are going all outL HU, speakers, amp, sub(therefore dynamat also) you are going to be looking at anywhere between 600-2k. Most systems of good, above average quality will set you back aroudn 1200-1500 unless you bargain shop over a longer time.

Heres a pretty well acknowledged template you can use when designing a system...
Speakers are normally 4ohm subs at 2ohm
That means, get an amp that will put out 4ohms to speakers and one that can put out 2ohm to the sub, or get one 4 channel amp that can do both.
Depending on the speakers you buy will depend on what amp you need.
For instance: if you buy $15 shit speakers, you can pretty much get any amp, and it will sound like shit. But if you buy good speakers 100-500 the quality of the amp will play a factor.

Keep things simple. Go with quality name brands. You can never go wrong with JL audio for amps and subs, alpine is always a good deck choice, and speakers are more up to personal preference and music choice.

Here's a decent startup system that wont set you back a whole lot
HU - alpine cda-9857
speakers- Alpine, Boston Acoustic, Diamond Audio, Focal
Sub- jl Audio w3
amp- jl audio 300/4 (this could probably satisfy your listening needs)

None of this is written in stone, nor is my person preference, but if you are just looking for a system that people go...."sounds good" you will probably be happy withthis set up.