Need help understanding AMPs and SUBs

[bored]

Hi there, this is my first post. Just joined to learn more.

I'm hoping u guys can help me comprehend a little bit more about ICE.

Assuming these are the specs for an AMP:

4 X 70W @ 4 Ohms
4 X 100W @ 2 Ohms
2 X 200W @ 4 Ohms (Bridged)
2 Ohm stable

And these are for the SUB:

RMS 180W
MAX 250W
Impedance 4 Ohms, SVC

These are the few doubts I currently have:

1) If CH1 & CH2 of AMP goes to FRONT COMPONENT LEFT & RIGHT. CH3 & CH4 is bridged to SUB. How much power is going into the SUB? Is it 200W @ 4 Ohms? Cuz I believe when the AMP is bridged, it will be 2 Ohms, does this means 400W into the SUB?

2) The SUB's impedance is 4 Ohms. The bridged AMP is 2 Ohms. Any harm? Or what will happen?

3) Alternatively, is it possible to run CH3 & CH4 of the AMP at 4 Ohms? I think for that the SUB goes straight into either channel instead of bridged, but then it will be imbalanced. Any advise?

4) The AMP has 2 pairs of RCA inputs. If the HU packs only 1 pair of RCA outputs, is it the norm to use a Y-cable to split the output in order to connect to the 2 inputs? HU Left -> AMP CH1 & 3, HU Right -> CH2 & 4?

5) For HUs with 3 pairs of RCA outputs, FRONT/REAR/SUB, is the connection going to be like this: FRONT -> CH1 & 2, SUB -> CH3 & 4, ignore REAR?

Please advise.

Thanking u guys in advance.

 

[Kippo]

1. 200W to the sub. Impedence load is set by the sub. The amp wont know a thing.

2. u got it wrong. If impedence load is 4ohm, the amp will see 4ohm whether it is bridged or not.

3. refer to above.

4. yep. Just use Y-splitter rca cable. If you amp has selectable input, use it.

5. the SUB pre-out from the HU is for non-fading & some control for higher end HU eg. xover, EQ, level.
preferable to just connect using Sub pre-out. Forget about the rear pre-out.

 

[oldskolboyz]

Hi there, this is my first post. Just joined to learn more.

These are the few doubts I currently have:

1) If CH1 & CH2 of AMP goes to FRONT COMPONENT LEFT & RIGHT. CH3 & CH4 is bridged to SUB. How much power is going into the SUB? Is it 200W @ 4 Ohms? Cuz I believe when the AMP is bridged, it will be 2 Ohms, does this means 400W into the SUB?

2) The SUB's impedance is 4 Ohms. The bridged AMP is 2 Ohms. Any harm? Or what will happen?

3) Alternatively, is it possible to run CH3 & CH4 of the AMP at 4 Ohms? I think for that the SUB goes straight into either channel instead of bridged, but then it will be imbalanced. Any advise?

4) The AMP has 2 pairs of RCA inputs. If the HU packs only 1 pair of RCA outputs, is it the norm to use a Y-cable to split the output in order to connect to the 2 inputs? HU Left -> AMP CH1 & 3, HU Right -> CH2 & 4?

5) For HUs with 3 pairs of RCA outputs, FRONT/REAR/SUB, is the connection going to be like this: FRONT -> CH1 & 2, SUB -> CH3 & 4, ignore REAR?

Please advise.

Thanking u guys in advance.

1) 200wrms at 4ohm.. 2ohm stable.. doesnt mean it stable at 2ohm bridge.. alot ppl misunderstanding about it...

2) Your amp not stable at 2ohm bridge... 2ohm only can get if you have dvc 4+4ohm or 2pc svc 4ohm sub wired in parallel.. if you do this, you shorthen your amp life.. & your amp will cut off in short period due to very hot..

3) You need to bridge it to run your sub woofer... as I said earlier ... your amp will not getting 2Ohm in bridge mode...

4) Yup, coz it is cheaper way to run comp set & woofer but ... the amp should have built in crossover.. if the amp dont have it than you need pre-amp or e/cross.

5) Yup, but need to make sure that HU have built-in crossover.. if have than it good no need preamp or e/cross.. for basic set-up laa...

Actually the most inportant is crossover.. without it we can damage our comp set or woofer.... doesnt matter either it's in HU or Amp.. as long you have it....

 

[bored]

Kippo, oldskolboyz

Thanks bros. It's all in my head now. :shades_smile:

I'm planning to change to an Alpine CDA-9857 or Pioneer DEH-6850MP.. in terms of functions/ flexibility, which HU is better? Or how about the new Kenwood KDC-X7533U? The USB function is really tempting. Come to think of it, when I wanna listen to MP3s I can just plug in my thumbdrive, don't have to burn a CD at all.

I think all these HUs come with crossover right?

 

[hi1983]

Alpine CDA-9857 if u can

 

[calvinhpk]

bored.....ask so many place ar??? hahha
so...understand now???

what's ur budget for HU??
i never like listen MP3 in the car....the SQ is so bad....hahahhaah

 

[bored]

hi1983.. I know! The 9857 is just awesome.


calvinhpk.. Haha I just copy and paste. Yes yes.. very clear now. U guys rock ;)

Mmm.. 6850 selling for 1K in this forum.. and I think 9857 is around 1.3K. Wonder which ICE shop selling cheapest? Budget more or less around these two HUs.

Cuz i get bored very fast listening to CDs. Everytime gotta change CD. When I saw the USB thumbdrive function I thought it's useful, don't have to burn CDs, just copy and paste. LOL.

PS: If u set the bitrate to 192kbps or higher, it helps a lot ;)

 

[Kippo]

why dont u just burn mp3 cds?

 

[bored]

Kippo

Yup that's what I currently do. Just thought that a thumbdrive will be more flexible. It's fast too, just copy and paste the tracks and you are good to go. Besides, there are times when you are at your friend's place and you want a copy of that tune that's currently playing, you just copy it into your thumbdrive. No hassles.

Anyway, this is just a tiny preference. I would still prefer a player with good overall performance in terms of SQ, tuning functions, flexibility, etc. That's why I am torn between those players I listed prior. All have their own pros and cons. And that's why I need opinions from you guys ;)

 

[nicholaslkh]

Kippo

Yup that's what I currently do. Just thought that a thumbdrive will be more flexible. It's fast too, just copy and paste the tracks and you are good to go. Besides, there are times when you are at your friend's place and you want a copy of that tune that's currently playing, you just copy it into your thumbdrive. No hassles.

Anyway, this is just a tiny preference. I would still prefer a player with good overall performance in terms of SQ, tuning functions, flexibility, etc. That's why I am torn between those players I listed prior. All have their own pros and cons. And that's why I need opinions from you guys ;)

Bored, you see arguing between the superiority of HUs is a never ending one and it is likely we will see casualties just like in a few other threads where our bro from Seremban kena tembak. Even brand superiority debate can go for years.
Judge them based on what u place as priority. For eg. functions (flexibility) VS appearance/perception(vanity) for a given budget. SQ is something very subjective and individual based. Major manufacturers such as Alpine, Pioneer, Clarion, Eclipse, JVC, Kenwood, Sony, Blaupunkt, Panasonic produce reasonably reliable products.

If u ask me personally, I prefer the Pioneer 6850 based on its functions for the given budget compare to the Alpine 9857. Then and again I want to say is that it is all up to individual's preference.

 

[bored]

nicholaslkh

Thanks for your explanation. Based on your preference, could you tell me what 6850 has that 9857 lacks? I mean you chose 6850 for a reason, could you tell me what it is? I'm having a hard time choosing between those two. Maybe after this I will see the entire picture and make my right choice. Don't wanna make the same mistake twice by buying one HU, and after a week realising I should get the other for some functions that I may need down the road.

 

[Kippo]

just look the specs of both HU. You can find them by doing google. I dont see the need to ask ppl to compare for u when u can do the comparison urself. Do u homework.

 

[bored]

Kippo

In my previous post, I asked nicholaslkh why he chose 6850 over 9857. I said "Maybe after this I will see the entire picture and make my right choice." I wanted to know his deciding factor for there might be something I overlooked when comparing myself.

Besides, I joined this forum to ask and learn more. I won't mind if you don't wanna contribute and skip this thread. No hard feelings, really.

 

[nicholaslkh]

I agreed with kippo. My choice is based on the info I have collected from the websites. You can get the HUs specs from the company's website and for more info you can get it from certain sites that offer reviews by consumers. I did the same before I purchase my HU too. People make decisions based on assumptions just like economic theory 'ceteris paribus' the theory goes bla bla................... The functions that I found useful may not be the same to u.

For eg. what I found really useful is the EEQ functions with the Pioneer (7 band digital graphic eq). What I found in the Alpine outstanding is only BBE. The rest of the functions I think is almost similar but check for the pre-out voltage of both units. The Pioneer comes with BMX and I don't know whether the Alpine has the MediaXpander for MP3s. Some people like OEL and some prefer Biolite. Individuals place priorities differently. Weight all factors like price, functions, looks,ease of usage, warranty, reliablity, convenient, sales person attitude etc then make your decision. Should u find it too difficult to do the research yourself, just PM me and I will mail u the brochures for both Alpine & Pioneer offers.