Calculated Wattage Output. How far would you take it with my setup?

[badstang123 10+ year member]

Today I did the calculated method of setting the gains on my amps. I am running a Crossfire VR1000D for two new MB Quart Shallow Mount Reference subs and also running a Crossfire VR404 (75 x 2 @ 3 ohms in the front and 50 x 2 @ 4 ohms in the rear. The front speakers are Boston Acoustic Pro's and the rear are MB Quart P-series components) From my understanding Crossfire is a company that rates the wattage output at 12.5 volts not at the 14.4 voltage a vehicle will regularly run at.

On my VR1000D since the birth sheet on the amp was roughly 1300 watts @ 14.4 volts, I used a -3db 50hz sine wave to adjust the amp to that wattage output. The Crossfire VR404, however, did not come with a birth sheet, so I adjusted to 75 and 50 watts via a -3db sine wave. This leaves me wondering if I am able to adjust to a slightly higher output than 75 watts in the front and 50 watts in the rear without risking clipping or damage to the speakers I have.

For this reason, I was curious how far you guys think I can push the envelope. It is loud and crisp as can be right now but like anyone else, I am always looking for a little more no matter how loud it gets. So the question comes down to...can I push the VR404 any further and also can I push the VR1000D any further than tested? My listening is mostly newer rock type stuff but I do mix in a little rap and hip-hop here and there so it needs to works on both ends of the spectrum as far as music preference goes. Thank you for any input.

Best Regards

- Justin -

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[dB-r 10+ year member]

What tools did you use to set your power output? You need an AC volt an AC Amp meter both to actually know what your amps are putting out.... You can buy a AC Amp meter (clamp) for $100 at places like Sears. Only way to get accurate readings, and only way to know actual impedance at specific frequencies.

 

[badstang123 10+ year member]

What tools did you use to set your power output? You need an AC volt an AC Amp meter both to actually know what your amps are putting out.... You can buy a AC Amp meter (clamp) for $100 at places like Sears. Only way to get accurate readings, and only way to know actual impedance at specific frequencies.

I disconnected the speaker wires, put the 1K or 50hz sine wave on repeat and was reading in AC voltage at the speaker terminal using a Fieldpiece HS26 meter.

I have a clamp as well as a million other gadgets but did not use them. I used the process to set gains that was posted on this site by jmac I believe. Is there something else I should be doing as well?

 

[wishbone 10+ year member]

If you had AC voltage in your speaker you would be in a lot of trouble ! //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

WB

 

[dB-r 10+ year member]

LOL, no AC voltage is what goes to the speaker.

You need to measure Amps AC and Volts AC to the speaker to determine power output, and load. You cannot in any kind of way accurately measure wattage output with only a voltage reading.

 

[oldschool4me 10+ year member]

If you had AC voltage in your speaker you would be in a lot of trouble ! //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif


WB

//content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[dman4486 5,000+ posts]

If you had AC voltage in your speaker you would be in a lot of trouble ! //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif


WB

//content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif STFU

 

[dB-r 10+ year member]

Those things posted here about setting gains with a DMM should really be taken down, it's not accurate. Need a Clamp AND a Volt meter AND an oscilloscope to do it right..... Meh..

 

[dman4486 5,000+ posts]

Those things posted here about setting gains with a DMM should really be taken down, it's not accurate. Need a Clamp AND a Volt meter AND an oscilloscope to do it right..... Meh..

not true....need a dmm and a birthsheet

 

[dB-r 10+ year member]

Lol...

 

[Grinder1989 5,000+ posts]

If you had AC voltage in your speaker you would be in a lot of trouble ! //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif


WB

Now that is sig worthy. Do you put DC to your speakers? How's that working for you?

 

[tRiGgEr 5,000+ posts]

Those things posted here about setting gains with a DMM should really be taken down, it's not accurate. Need a Clamp AND a Volt meter AND an oscilloscope to do it right..... Meh..

Not everyone has access to these pieces of equipment. Especially a O-scope.

And to even think that the average car audio user can't setup there equipment without it is, well retarded.

 

[Grinder1989 5,000+ posts]

Setting gains is a waste of time.

 

[badstang123 10+ year member]

LOL, no AC voltage is what goes to the speaker.
You need to measure Amps AC and Volts AC to the speaker to determine power output, and load. You cannot in any kind of way accurately measure wattage output with only a voltage reading.

It seems many others agree with you. I was under the impression that the gain setting thread was the accurate way to do things. But if it is not I'm all ears on the best means to do so.

If you were me what process would you use to accurately set my gains to avoid clipping while still acquiring maximum output. Is it even possible without a o-scope or am I relying on my ears? As stated I have a meter that can measure ac voltage as well as a clamp I can connect to it. I do not have a o-scope though unless a SoCal local with one wants to help out //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif Also due to the setup on the meter I can only use the ac measurement or the clamp, one or the other at a given time. Not both simultaneously.

I'm always open to suggestions so tell me what you guys think. Thank you for the input so far.

Best Regards

- Justin -

 

[dB-r 10+ year member]

I use two meters at once, they are Fluke 73III one has the 400A AC Fluke Clamp on it. You can use a cheap portable LCD O-Scope like the Velleman HPS10, I think you can get them for about $100 and will come in handy for all sorts of things not just setting gains, but that is one use, yes and yes to avoid clipping entirely you will need to adjust your gains properly with the scope, relying on your ears is good enough too (for most, some are more anal types and want to make 100% sure it's perfect, but as someone else pointed out here setting gains is a waste of time, it's really NOT necessary to be so anal about it unless you are a super duper sound quality freak, you can just set it by ear as long as you are experienced and have a good ear for clipping, you can also detect clipping with a DC DMM measuring the DC Volts going to your speakers it should be minimum, should be all AC if you are noticing a great deal of DC then either your meter is inaccurate or you are clipping the output signal, don't put it past your meter to be inaccurate, the only meters I trust are my Fluke meters.... have seen strange things with all other brands of meters....).

AC Volts x AC Amps = power output in watts

AC Volts / AC Amps = Actual impedance amplifier is seeing from the load at that specific frequency