4 channel amp advice

I have replaced my standard headunit in my fn2 to a kenwood double din 4016bt. I have also now replaced all standard speaks for vibe.
Front 6.5" blackair components crossovers and tweeter 115w rms 345w peak (4 ohm)
Rears 6.5" coaxial black airs 90w rms 270w peaks (4 ohm)
They are a lot better than standard speakers but nowhere as good as they should so i want to amp them. I have since checked the outputs from the kenwood headunit which i thought was 4x50 rms but this was actually peak so the rms was is only 22w !
I am looking for a 4 channel amp for each speaker ... now when it comes to speak and amp impedance i know very little so i thought for ease it would be best to get an amp with 4 ohms impedance to match all 4 speakers with out having to bridge channels or run speakers in series/parallel etc .
I have only budgeted around £100 for the amp. Theres 2 im looking at unless anyone can advice anything more suitable. The 2 are :
FLI underground fu720 4 channel 720w
@ 4 ohms 70w x4 rms and i think around 180w peak per channel

Pyle power PLA4273 2000w 4 channel rms @4ohms 120w x4 and 500w x4 peak im not sure if this is too powerful or not ? 120w sits between rms and peak for all speakers but 500w is obviously too big would this be fine as long as i keep gains turned down.
I know neither of theses are great brands but was thinking as i dont wanna spend a great deal and only want a bit of a boost to my mids and highs 1 of theses would be ideal assuming the 1 is not power or any other suggestions or advice would be brilliant.

Also have a vibe srl active subwoofer already wired up working fine.

Also just found a vibe 800w peak 4 channel amp which would keep everything the same. 75w x4 @4oms

I wouldn't trust either brand honestly.
A quick search on eBay has shown there are plenty of 4 channel amps from brands like Alpine or Kenwood for inside your budget.

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Ye i can see what you mean i did look at the good brands but as my budgets quite low seems best rms im getting for the money then is around 50w rms x4 thinking is this a little low to get best possible sound/ performance ive never amplified components so im a complete notice with how they will react to 50w compared to 70 or 100w
Has anyone done their door speakers if so what wattage

I have used the same Alpine amp in my cars for the last 15 years and it has not skipped a beat. If it failed i wouldn't hesitate getting another one tbh.

stu1873 said:

I have used the same Alpine amp in my cars for the last 15 years and it has not skipped a beat. If it failed i wouldn't hesitate getting another one tbh.

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Is that 4 channel too ? Do you know the rms also am i wrong in thinking i need output of at least the rms of the speaker's or would i be surprise how much say 50wx4 makes compared to just the head units amp

Do not, unless you know exactly what you're doing, use an amp with more power than the speakers. If you turn up the amp too high in that situation, you'll damage the speakers. In the other situation (where amp power output is lower than speaker RMS) the least pleasant situation is you just can't get the gains you want and the amp (when turned to maximum) is out of its linear response area and either ends up soft-clipping or just sounding rubbish.

Best is to get items closely matching one-another.

Also, a cheap/unknown amp may have all the right numbers on the box, but might either not have a very linear response, or clip terribly at the upper range, or be unable to deliver its rated power to all 4 channels simultaneously.

My home amp is 60w/channel and I don't think I've ever made it much past half-way on the dial. Unless you're planning to enter some kind of competition to see if you can crack the welds on your car or blow out the windscreen, I think 50w/channel is probably fine.

In your situation (and if I could find some more money) I'd think more about running two separate amps, one at the rear at something like 200w/channel and another for the front at 100w/channel.

There are car audio forums out there too though and they have a lot more experience in this area than many of us, maybe you should ask there too?

When I had an install in my FN2, had a 4 channel amp running the front speakers and a 12in Sub (all from Hertz)
The rears were bone stock (you never really need to upgrade the rears as you don't really hear them and were run off the head unit.

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mike.h said:

Do not, unless you know exactly what you're doing, use an amp with more power than the speakers. If you turn up the amp too high in that situation, you'll damage the speakers. In the other situation (where amp power output is lower than speaker RMS) the least pleasant situation is you just can't get the gains you want and the amp (when turned to maximum) is out of its linear response area and either ends up soft-clipping or just sounding rubbish.

Best is to get items closely matching one-another.

Also, a cheap/unknown amp may have all the right numbers on the box, but might either not have a very linear response, or clip terribly at the upper range, or be unable to deliver its rated power to all 4 channels simultaneously.

My home amp is 60w/channel and I don't think I've ever made it much past half-way on the dial. Unless you're planning to enter some kind of competition to see if you can crack the welds on your car or blow out the windscreen, I think 50w/channel is probably fine.

In your situation (and if I could find some more money) I'd think more about running two separate amps, one at the rear at something like 200w/channel and another for the front at 100w/channel.

There are car audio forums out there too though and they have a lot more experience in this area than many of us, maybe you should ask there too?

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Thank you ! You pretty much answered everything i needed to know there to be honest like you said im not after competition standard DB just wanted some crisp and clear/clean vocal mid bass and high end sound because with the sub everything sounds drowned by bass and very little sctual vocal noise so even when musics turned up bass is loud and backing music the actual singing is very quiet then if i turn down bass its just all quiet so i think ill do what you said under power or match the speakers rms as close as possible with out exceeding it. I shall price up the 2 amp option also. I did look on car audio forums but i was way out of my depth it was getting far in depth haha. Shall keep u posted on what i decide and how it goes may put a thread on for someone considering it with thier fn2. I understand the principle of wiring up the amp abd everything it was just the ohms law and all the rms and peak watts thats been confusing me. Thanks all

Lukephillips said:

... like you said im not after competition standard DB just wanted some crisp and clear/clean vocal mid bass and high end sound because with the sub everything sounds drowned by bass and very little sctual vocal noise so even when musics turned up bass is loud and backing music the actual singing is very quiet then if i turn down bass its just all quiet so i think ill do what you said under power or match the speakers rms as close as possible with out exceeding it.

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I suspect that the bass is overloud because of a few things. The crossover is likely set too high (so the bass driver is trying to move at a rate to cope with what should be managed by the mids). The amp for the bass driver may well be too weak (people tend to buy quite cheap subwoofers for some strange reason), this will lead to the bass sounding "warm" or "rounded". This is because the sub's amp can't deliver enough power to move the cone of the bass driver quickly enough. If you're running a decent stereo (or cheap but high power) there's a high chance your electrical system will also need some help, either additional batteries or a set of quite large capacitors to cope with the instantaneous demands of music, otherwise you'll suffer similar issues (the instantaneous current demands can't be met quickly enough).

Imho, unless you're doing something very specific, you shouldn't need a sub at all, vocals shouldn't be anywhere near that. So long as you have enough power going to the mids things should sound very nice without (and it'll save you some boot space). I might just be getting old though

There's absolutely no point in amping up the rear speakers, they are fill only and you want all the sound to come from the front. How many concerts have you been to with speakers behind you? If you want crisp and clear sound then get components and dynamatt your doors, you'll most likely need a fair amount to get the bass response you want. I'd also be looking at a higher quality 2 channel class D amp if budget allows over a 4 channel.

With my SQ build I get comments on some tracks about a 'lack of bass' but mines been tuned to be accurate rather than booming for the sake of it. It's nice and loud but also really clear too!

Krzys said:

With my SQ build I get comments on some tracks about a 'lack of bass' but mines been tuned to be accurate rather than booming for the sake of it. It's nice and loud but also really clear too!

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Thank dog for that, I had some Saxo pull up next to me at the lights on the wkend. 3 people in it, driver with baseball cap and seat tipped way back, bass driver making every panel in the thing reverb like the world was coming to an end, gunning his engine as the lights went from red to amber. I let him chirp off the line. Just... ugh.

Bass should be accurate, not insane.

Typical Bose commercial way of making things sound, turn up the bass, must mean it's good, right?

Obviously! :lol:

I'm too old for overpowered bass giving me headaches, been there and done that!

The USB I have though is 32GB and I almost literally have a bit of everything on it, can't beat Escala turned up loud on a chilled drive out.