Measuring voltage and setting gains?

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06-08-2004, 01:06 PM

Sterling

50 Watt CAFz'r

Thread Starter

Join Date: Feb 2001

Posts: 166

I've always been under the impression that the lower the gains the better the SQ? But after reading a few posts this may not be true?

I've always kept my gains low, should I be trying to match them?

How do I do that? Detailed steps would be greatly appreciated

I have a Denonford 8250 with 16 volts balanced (Symbilink) out to my Zapco amp and a Crossfire sub amp with regular RCA's that I think maxes out at 5 volts.

Thanks

06-08-2004, 08:21 PM

mqqball

500 Watt CAFz'r

Join Date: Dec 2001

Posts: 550

By matching the gains to the output of the headunit you are ensuring that the amplifier will develop its maximum output. For example, if the maximum continuous output of the headunit is 3V and the gain on the amplifier is set at 3V, the amplifier will produce its maximum output when the input signal is equal to 3V.

In terms of setting the gains, to methods can be used. The most common is by ear which isn't very accurate (I can't speak for the experienced members on the board). A more concrete approach would be to use a test-tone CD and O-scope.

I'm a little short on time so I can't go into specifics regarding the process but basically your trying to determine when the headunit's output begins to distort and when the amplifier begins to distort on its output when the headunit signal is at its maximum (continuous output).

06-08-2004, 09:00 PM

Dereck Waller

Guest

Posts: n/a

Get a test disc with 1K tones at 0, -5, -10 dB reference levels. For pure SQ use 0 or -5, for everyday systems use -10 dB. Turn all gains down (amps, eqs, crossovers etc). Play the test tone and put it on repeat. Turn up the deck until you hear the tone change, it will be clearly audible, then once it changes turn it back a click or two (alot of decks won't clip so just keep the volume at max then). Proceed to the next component in the signal chain (eg. eq) and turn up it's gain until you hear the tone change again. Turn it back a click or two. And so on down the signal chain until you get to the amps. I usually turn down any sub amps or such to match the rest of the amps levels, you might have to turn the mid amp down to match the subs, the point being just turn amps down to match between subs and mids, never bring an amp up to match at this point.

06-08-2004, 09:56 PM

thereal7

50 Watt CAFz'r

Join Date: May 2004

Posts: 65

DWVW, I have a question. I am setting up my system this weekend...nothing competition or major, but an everyday driver. The system is an Eclipse CD3434, Alpine Mono sub amp, Alpine F240 4 channel amp. I have heard that the Eclipse decks don't put out a clipping signal, but you then mention to set it to max. Wouldn't this get super loud once you start adjusting the amp's gain?....

sorry...I am a total noob to car audio.

Thanks
~scott

06-08-2004, 09:59 PM

Dereck Waller

Guest

Posts: n/a

It can get loud in the car, but it should be tolerable for a minute or two, if your amps are in the trunk I recomend making sure you are quick to adjust the amps. I don't like to have high output tones through my speakers for more than a couple minutes at a time.

Also make sure your bass and treble are flat, and keep any eq or anything off as well, then don't vary it too much when using the deck.