I don’t get it

[Ben P]

Ive got a pair of 6" Infinity components in my front doors which I mounted using some door builds I made.

They are the 605c which have 240w max and 85w RMS

I am running these from an Alpine T407 amp which produces 2 x 120w max and 2 x 50w(ish) RMS.

When I matched these up I expected the speakers to be able to take the amp on full gain, as their rms rating is higher than that of the amp.

However if I have the gain on the amp set at anything more than halfway, they distort.

This means that either I have to lower the gain on everything else (6x9s) or the sound is very quiet in the front of the car. In fact sometimes it sounds like there are no front speakers connected.

Why is this? I thought that if the speakers are rated higher than the amp, they should be able to take the full power ie. gain cranked all the way up.

Please advise me on how to set this up coz its really annoying me.

Thanks.

By the way I also have 2 pairs of 200w max Sony 6x9s being powered by a 4x80w max amp. The gain on this amp can easily be set to full and the speakers will still not distort.

 

[Scott_Mck]

The gain is NOT a volume control, it is used to match the pre-out voltage from your head unit. If you are running a relatively standard head unit, then the gain should be set to approximately 1.8v. better head untis have 4 volt and higher preouts allowing the gain to be set higher due to the better quality signal.

If it isnt loud enough, buy a bigger amp...do not "crank the gain right up" as it will damage the speakers, amp and even the head unit over prolonged periods of time.

The best rule of thumb is to buy the biggest amp you can afford and run the gain as low as possible, this gives the best compromise between volume and quality, without sacrificing safety.

If your amp has no markings for the gain, then put on a very dynamic piece of music and have the gain turned right down, set the volume level on your head unit to approx 3/4, then slowly increase the gain on the amp until the speakers start to clip (distort). Then this is the level the gain should be set at.

Scott

 

[Ben P]

Cheers mate that might help explain the following:

I have just replaced my head unit.

My old unit had 2x 2v pre-outs
My new unit has 3x 5v pre-outs

Since swapping the units over, my overall volume level has decreased dramatically. In fact unless you turn the head unit volume up to 15 (out of 35) you get virtually no sound at all.

Does this mean that I will be able to increase the gain of my amps in order to match the new higher outputs from the head unit?

Cheers for any help

 

[Scott_Mck]

Should explain a few things...not necessarily the drop in volume...

However, yes you can now turn the gain up to accomodate the cleaner signal path. Use the method I outlined above and you should be well on the way to a decent sound.

Scott

 

[Pysco]

Yeah, I never realy understood this either, surely the amp is simply a power amp, ie a voltage to current converter. This would mean youd either have a volume knob or nothing, anyone whos looked at a guitar amp ot into high end HiFi can see this, gain is a term used in pre-amps, ie voltage gain. If your amps are distorting when cranked up it surely means there clipping, ie the power supplys (the amps regulated power supplys) are running out of juice and cannot keep up the demand.

 

[Ben P]

Thanks for all the help. I will spend a little time today setting them up properly.