Amplifiers

[Retro Pug 0 1 Cars]

I'm not ICE mad but do like a quality sound as I spend at least 2hrs a day in the 205.

 

I'm planning on getting some Focal components(inc tweeters) for the front and use my existing pioneers for the rear. I've got a 10" Sony sub and box that I was planning to use also.

 

Do I need seperate amps for the sub and then speakers? What should I look for?

 

Ive got a quite a decent Alpine head unit to run the system.

 

Cheers

John.

[large 33]

Your best bet is to mach the speakers to an amp, look at the R.M.S value on both the speakers and amp and match them up and you wont go far wrong. I would get a 4 channel amp for the speakers and a mono dlock for the sub.

 

If you only want 1 amp you could get a 4 channel amp and run the front speakers of channels 1&2 and bridge channels 3&4 and run the sub off that. Then run the back speakers off the head unit.

 

Only just noticed you are down the road from me I could give you a hand if you want.

Edited January 15, 2009 by large

[Retro Pug 0 1 Cars]

Only just noticed you are down the road from me I could give you a hand if you want.

 

 

Thanks for the reply makes sense! Also thanks for the offer may just take you up on that!!

[DrSarty 90 1 Cars]

As Huw says, but he didn't explain 'matching up'.

 

Speakers have a max power rating, which frankly is fairly meaningless. However, Focal are the dog's gonads of speakers; real quality. So on amp choice I would suggest you follow this advice below which just elaborates on what Huw said.

 

You need 5 channels of amplification - whatever approach you choose, you MUST have some form of crossovers (most amps have them in now) which cuts off the low bass from your Focals, say 60-80Hz never gets to them. PLEASE follow this advice, as it will protect them, make them handle more power and stress them less so they sound better.

 

The sub also needs a crossover, preferably adjustable to cut off the high frequencies, say 80-100Hz plus from ever reaching it. The higher the crossover frequency the more the bass image becomes dragged towards the back; i.e. lower is better.

 

Some high quality head units have these crossovers built in as a feature, which is ace. Otherwise use what the amp has or install an active crossover between head unit and amp(s).

 

So....approach 1 is buy a 4 channel amp, where stereo pair A runs the front Focals, leaving the other 2 channels to be bridged to mono to run the sub. This is assuming it is a single voice coil sub and needs just a pair of + & - inputs. Then just use the head unit's built in amplifier to power the rear speakers. The head unit power will be plenty for the rears, but BEWARE you will have no means of rubbing out the low bass from getting to these speakers, which will ultimately destroy them, the head unit or generate distortion, UNLESS you use the fader to quieten them down a tad.

 

Approach 2 would be to get a 6 channel amp. This is likely more money, but will mean everything has proper power, is as simple to install as any other single amp and will almost certainly mean control over frequencies going to speakers AND better sound overall than using approach 1.

 

Approach 3 would be a 4 channel amp - for front Focals & rear (fill) speakers - all with crossover capability I suspect, PLUS a dedicated bass amp, which could be attached to the bass box with a special plug (Vibe make one) for making it removable easily. This is what I have, and despite meaning a little more complicated installation that Huw or I could help you with (because you'll need a fused distribution block for the power for both amps plus a earthing block) it WILL absolutely give most flexibility, tuning and best sound, but cost a little more.

 

My golden advice is below though:

 

- referring to the 'matching' Huw mentioned. If your Focals have a peak power rating of 200w, then your amp should be a minimum of 100w RMS. This RMS is most important, as it's really what the amp produces. As said, peak is a meaningless figure really, and your amp's RMS output should be around 50% of the speakers' peak handling capability.

 

- buy a good quality amp, such as Genesis, Focal (I think make them too), Alpine, Kicker, JL Audio; basically NOT a lime green pile of crap from Halfords. Search for 6 channels amps on E-Gay or see your dealer, asking for display or ex-demo to save some sponds.

 

- AND ABOVE ALL, installation quality is paramount. Don't cut corners, especially with power as it's friggin' dangerous, and mount those Focals properly i.e. with solid MDF baffles or they'll sound no better then some Jet Sound corner shop w*nk unit! Trust me on this. Fuse the power from the battery (to either the amp or power distribution block in the back) no more than 18" from the battery. Use the correct guage of wire for the amps (peak current) that the amplifier(s) can pull. This can usually be gathered from either the specifications of the amp(s) or by adding up the fuse ratings fitted to them. Earth wires must go to a very good, paint rubbed back, bare metal earth. And if you use 2 amps, best to ground them at the same point.

 

Also secure the bass box properly.

 

Then finally it's all about setting it up properly. In simple terms that means turning all amp gains down to minimum and concentrating on individual speakers one at a time, i.e. front / rear / sub. Have the head unit flat - you do NOT need loudness on, ever, with a sub fitted - and wind the volume up to 75%, and then NEVER go over that volume when playing your system. This will ensure a clean, unclipped (which fries speakers) signal gets to the amp(s). Then slowly turn up the gain control on the amp channel in question until you just get some distortion, then back off a tad. Do this for the Focals on their own, then the rears (if you have an external amp on these), but remember to back them off a tad more to make sure the Focals are doing most of the work, and then finally the sub.

 

There you go; all in one hit. Good luck.

 

EDIT: In fact bollox. If you're coming to the Wales meet on Sunday (Huw is too), I have a 4 channel amp which'll do a fine job for £10 you can have. It's Legacy, which is mid range but plenty, leaving you to buy a bass amp only. Whatta ya reckon?

Edited January 15, 2009 by DrSarty

[richsmells 2]

Pin this!

[large 33]

As the good Dr said. I can’t believe that I mist out about the RMS figures. I for one would run two amps as I find you have far more control, the last car I fitted amps into I used 4. One 1200w four channel and three 1500w for the subs (1 amp per sub) and yes it was loud.

[DrSarty 90 1 Cars]

Pin this!

 

Thanks. Once I started typing I couldn't stop!

[Retro Pug 0 1 Cars]

Thanks. Once I started typing I couldn't stop!

 

 

This is awsome and needs to be pinned!! Thanks so much for this really helpfull!!

 

I'm looking to get the speakers from here Car Audio Security

 

Would this amp be ok Alpine to start as your Option one? I could then add to it later to build to option 3?

 

Cheers for all help

John.

 

Edit: Only just spotted your offer of an AMP. If I can make it I'll take it. Really want to attend but family do on Sunday makes it tricky, which is why I have not stuck my name on the list...... If I come it would be more like 8 - 8:30, but dont want to say 'yes' and then not show...

Edited January 16, 2009 by Retro Pug

[DrSarty 90 1 Cars]

That Alpine amp will be perfect. Not only does it have the 3 channel operation (i.e. 2 channels bridged for the sub) and the high pass xover you need for the front speakers, say set at 60-80hz, the low pass xover you need for the sub, say 80-100hz, BUT it also has a sub-sonic filter which will protect the sub and give you more bass welly.

 

That sub filter will be doing exactly what the HP filter for the Focals will be doing, i.e. not making them try and play sound they can't cope with.

 

The Legacy amp I'll bring regardless is slightly more powerful, but it's older and doesn't have the subsonic filter. It'll do almost exactly the same job and leave you £114.99 better off.

 

Stay with the Focals too, as you can't buy much better, and you really want to focus your sound to the front and leave the rears at a relatively low level.

 

Also note the Alpine amp's current draw. It has 2 x 15amp fuses built in so can technically draw 30amps all day long - not that it would - and probably 40amps at brief peaks. We had a big argument with some young guy on here who didn't think 12volts was dangerous. When you realise 0.5amps can kill, you start to appreciate why I said proper installation with the correct fusing and wiring is essential when you have 30+ amps wanging around your lovely earthed metal chassis. My previous 5 amp system had 2 extra batteries and a 300amp main fuse!!!!!!!!!!!!

 

Rich