Using an amplifier in Tri-Way Mode: Enjoy Great sound economically

From the article How to determine power needed for speakers?, We derive that most head units can’t sufficiently power the speakers. It makes more sense to power your speakers with an amplifier. And considering the construction and power handling capacity of Subwoofers, it becomes mandatory to use an amplifier.

In a “basic” setup, we have a head unit, front speakers (co-axial or components) and rear speakers (usually oval, co-axial). If we have such a basic system that makes use of speakers of “low power handling” but “high sensitivity”, we can optionally skip the amplifier, keeping in mind our budget for the car audio. We know, we can’t expect it buzz all the tones with high fidelity, because, practically it can’t: The “low-frequency” component is missing from our system. We said “bye” to the thump!

In “decent” setup, we have a head unit, front speakers (again be it co-axial or components) and rear speakers (usually co-axial). Say, we are keen on loud music and we love “bass” and hence we added a decent tight bass using a subwoofer. And with a subwoofer, we let our pockets open to an amplifier. Well, amplifier comes with an extra expenditure for its wiring kit. That’s fine, no other way, we took it. Now we have almost all the frequencies in the audible range (20-20kHz), though some frequencies below 30Hz or 40Hz depending on the size and quality of subwoofer. And We lose a bit of “high-frequency” notes, depending on the construction and quality of tweeters. Overall listening experience is good ..infact decent, as we wanted it to be!

Now comes a “Dil Maange More” setup. In this we want louder sound, more thumps in subwoofer and more chills. In a sense we want very detailed music. We can achieve it with a head unit, a component speaker system in the front (Remember: We wanted detailed sound with good chills and clean separation), a co-axial speaker in the rear and a Subwoofer and amplifier. So finally we have a system that gives out almost all frequencies and a detailed music. Something really missing here … well, we hear all tones, but still … shall we say its unbalanced? Yes, that how its called as. It makes your music system high on bass and hence boomy. Whatz wrong?

Music becomes unbalanced, if the volume levels on each channel are not in near equal ranges. In the above system, we amplified our subwoofer but our front and rear speakers are not amplified; they are still directly fed by head unit, which would be obviously feeble.

We can resolve this using another amplifier to power the front and rear (optional). If one is tight on budget, the rear speakers can be directly run by head unit. In some case, irrespective of budgetary constraints, people get rid of powering the rear speakers from amp and simply run from head unit. This setup is called “rear fill”, meaning we are using the rear speakers just as fills and we don’t wish them to dominate.

Depending on the choice, we end up with a 2-channel amplifier or a 4-channel one.

With our own experiences with many such installations, we have seen that, “rear fill” approach sound good, doesn’t lose on loud sounds and creates a better sound stage! Some of our customers came up with the idea of excluding the rear speakers, thus saving some money and that too not at the cost of significant difference to the listening experience.

We have devised a bonus money saver technique for those, who want to go for “rear fill” approach or even get rid of rear speakers. That is instead of taking 2 amplifiers: one for from components and other for subwoofer, we can make use of a single 4-channel amplifier (such as Rockford Fosgate R300-4 )and power the front components using 2-output channels and bridge the remaining 2-output channels will be bridged and taken out as a mono channel and connected to your subwoofer. Well, it needs little proper tuning, not to set the pass filters wrongly. See the wiring diagram below:

This mode of wiring of amplifier is called “Tri-Way Mode”. It saves money for extra amplifier and its wiring kit.

We have been advising and installing many such “Tri-Way Mode” setups (using rockford fosgate and blaupunkt amplifiers) and have a good listening review in almost all installations. This is really a recommended thing, for someone who is really loves loud, detailed music and constrained in budget for the time being.