Thread: A question for car audio gurus

The amp will only make its rated power and no more, depending on the load in ohms

Assuming the subs are identical, and each has a 4 ohm voice coil in it, they can either be wired in series to present a 8 ohm load to the amp, or in paralell to present a 2 ohm load.

Now, invariably when you halve the impedance (load, aka resistance, measured in ohms) on an amp, you enable the amp to make double its rated power

Assuming you have a current ZX series Kicker 300.1, it makes a mere 150w rms (ignore the MAX, PEAK and PMPO, etc power figures) at 4 ohms, and 300w rms at 2 ohms

When you connect 2 speakers to one channel on an amp, you are halving the power that each speaker recieves, so with 2x4ohm speaker wired in paralell (2 ohm load) to an amp that produces ~300w rms at 2 ohms, you are giving each speaker 150w rms

There is no great problem with this, its hardly underpowering the subs (assuming the continuous power handling measurment is in watts rms) , and to make an accurate judgement I'd like to know what subs you have.

As for "handling" the power, the amp only really cares about power supply, signal and the load it is given, its the speakers that will die if you try feeding them too much power.....

given average subwoofer enclosure design/construction, its better to run less than the subs rated power, because without the optimal enclosure, the sub isnt capable of performing to its full capacity

also something to remember, for normal listening, even at high volume levels, your amp will rarely make its full power output.....

Excellent reply, and spot on. Only thing i would add is if it truly is a mono amp the you are only dealing with one channel, if it is a two channel amp you are bridging then you need to combine the power per channel, in accordance with the resistances stated in Sprint's reply, which rely on the wiring option you use (series or parallel).

cheers
Nick

somehow i suspect when he says "bridging" its referring to having the 2 subs connected either in series or paralell

The explanation given is spot on
A lot of "experts" get a bit confused and claim that it is dangerous to run a lower powered amp into a higher powered speaker. This is false!

What is wrong is to then turn the gain (volume) up to compensate. This makes the amp work too hard only to then fail and THAT FAILURE may do damage to the speaker. BUT if the volume knob is set below the distortion level, no harm should result.

There is more of a problem keping the current supply up to the amp. Some heavy wiring and VERY good connections are required.

In a car, given the close proximity and the system proposed, there is a very good chance that the occupants will be turning the audio level down before the distortion area is reached anyway.

A regular exposure to high level audio systems is one sure way to bring on hearing problems.

Some of the new anti-hooning pushes being made include banning of high-powered car audio systems. This would include anything that can be heard outside a closed-up vehicle in heavy traffic while the observer is standing at the roadside.

Hope this helps.


Rovers4

Originally Posted by rovers4

Some of the new anti-hooning pushes being made include banning of high-powered car audio systems. This would include anything that can be heard outside a closed-up vehicle in heavy traffic while the observer is standing at the roadside.

*sighs*

you realise, that kinda outlaws 99% of the FACTORY stereos installed in cars in at least the last 15 years?

In my experience the term bridging is usually applied to the amp, ie, the bridging of the two channels into one, not the speakers, in so far as it relates to the power output of the amp.

However, thrower, will get it.

cheers
Nick

Thanks for the replys guys, by bridging the amp I meant running both subs in paralell putting a 4 ohm load on the amp.

I rang the manager of the place that I bought the gear from because it was one of his staff that sold me the amp. He was a little confused why the other guy had sold me that amp, so he told me to take it back in to him and he replaced it with a bigger amp (worth twice the price) for no extra cost. A polk 600.1 that is the same brand as my speakers and subs and specified in the polk catalouge as the amp to run what I am trying to run. Also it is a mono amp with connections for 2 subs rather than putting 2 sets of wires into one set of holes like some others.

I am in no way trying to put a sound system in that will shake the car apart so I can look like a tool driving down the road imparing my hearing. I just like good sound and with some big trips coming up I am getting it sorted now. But I would rather have the amp running easily with the gain quite low than a small amp running to the hilt getting red hot, not good when attached to the back of a set of draws. I think a mistake that people make is using the gain on the amp as a volume control which it is not.

Thanks again for the replys
Andrew

what subs do you have?