match an amp to my speakers

[fenian672000]

hello guys ....few questions id like to ask

1.....i have recently fitted to all four doors pioneer TS-H1703 speakers, they are said to have a maximun wattage of 180 watts and a nominal wattage of 50 watts, my question is what is the power rating per channel that i would need from an after market amp to get the very best from these speakers

2......Obviously it would be a 4 channel amp to drive these speakers, but i still need to power up a sub, do u get 6 channel amps or would i need a seperate amp?

3....could i power the rear parcell shelf sub (which is 9 inch) from the new after market amp, or would i need to upgrade accordingly???

4.....whilst looking at amps and head units there seems to be 2 different power ratings , max and rms, which do i go by and what do they mean?

appologies for the amount of posts about basically the same things these last few days , but i just wanna spend my money wisely

cheers

 

[AndyMac]

1. max 50wrms (you could go higher but no real point on door speakers, unless you want the door cards to disintegrate)
2. 6ch are hard to come by though you can get 5 channel which is ideally what you need. Alpine do the V12 MRV-F450, which is 5ch, spec is 4 x 50wrms + 1 x 200wrms for the sub. If that's a bit too tasty then you can pick up an old style V12 MRV-F357 (4 x 40w + 1 x 150wrms) for around £80 on ebay, which is really all you need as Alpine V12's are very conservatively rated and the certificate you get with the amp is always rated at least 35% more powerful than the spec.
3. You need to replace the stock sub. It's only rated at 50w and it's shyte.
4. Max is irrelevant forget it. Only use RMS power ratings when comparing products. It stands for Root Mean Square, but is basically the average or continuous power of the amp at a set voltage (either 12v or 14.4v), so it's the power the amp is capable of delivering all day long within certain distortion limits. Peak or Max is just a marketing gimmick for the max power guys so they think they're getting more than they actually are. Any amp can hit 300w max for a nano second, but if it then sets fire to your car it's not really a lot of use.

 

[fenian672000]

Andy Mac yer a legend mate.

One other thing, the amps im looking at have diff ratings for 2ohms and 4 ohms

what is ohms and how do i know if i will have 2 or 4 ohms or maybe i should say how do you get 2 or 4 ohms

lol....if u dont ask youll never know

 

[AndyMac]

ohms is the impedance of the speakers you will be using, the electrical resistance the speaker presents to the amp i.e. a short circuit across the speaker terminals is 0ohms, so will blow the amp.
2 ohms is a very small resistance so can produce more power as long as the amp is 2 ohm stable i.e. it can cope with the additional current draw.
4 ohms is the standard impedance for most speakers.
2 ohms is really only relevant for subs however Bose use 2 ohm speakers in order to get more power from a smaller amp.
It has nothing to do with sound quality, it is purely about power delivery so a 200wrms amp driving a 4 ohm sub will produce something like 300wrms driving a 2 ohm sub. Some amps are only 2 ohm stable in multi channel mode i.e. they can't drive a 2 ohm sub when bridged, if this is the case then they won't quote a power rating for bridged with a 2 ohm load.
All non Bose Audi speakers are 4 ohm, most aftermarket speakers are 4 ohm, subs can come in all flavours, some with dual voice coils so that they can be wired in parallel or in series to present different impedances depending on the amp and config. e.g. two 4ohm subs or voice coils wired in parallel (+ve's joined together, -ve's joined together) present a 2 ohm load to the amp, whereas two 2 ohm subs wired in series (daisychained) will present a 4 ohm load to the amp.

 

[fenian672000]

thanks for the reply Andy

im gonna go w the alpine vi2mrv-f450 or pioneer gm-d515

im also gonna purchase a new head unit Becker Grand Prix in the red display

my question is what adapter do i need to connect the head unit to the audi plug???

 

[AndyMac]

If you're going with a 5ch amp then you don't need any adapters for the new HU. The adapters purely allow you to link the standard RCA's from a new HU to the non standard mini-ISO loom on the Audi. With new HU & amp you'll run proper RCA's so no need to hook into the Audi loom. The power connector is standard ISO on Audi's so this will plug straight in to the Becker though you'll have to swap the perm live & switched live or probably have to splice them together as newer Audi's don't have a switched live.