DMM/gain setting help?

[Mzlady 10+ year member]

im going to aim for 30.00 but im going to set it 29.5 and see if i can get away with that. op u gona give up on a dmm?

Yea i'm giving up on the dmm its just not accurate enough and if i'm going to drop money on another piece of equipment its gonna be an oscope.

 

[Stalin-ohaulic]

Yea i'm giving up on the dmm its just not accurate enough and if i'm going to drop money on another piece of equipment its gonna be an oscope.

OR you could just use your impedence at rise to set your gain. Oscilloscope gain setting is not quite as easy as it sounds. If you've ever used one you know that. It will certainly show you where it clips though.

 

[Mzlady 10+ year member]

OR you could just use your impedence at rise to set your gain. Oscilloscope gain setting is not quite as easy as it sounds. If you've ever used one you know that. It will certainly show you where it clips though.

Yea true. Well i'll find out whats going on for sure 2morrow.

 

[halfwaytohell 10+ year member]

hmmm

 

[halfwaytohell 10+ year member]

i think im going to not use a dmm as my first way of seting my gain. i might see what it says when i get it all set.its just im sure when u go and turn stuff back on your deck the number u come up with will change.

 

[Stalin-ohaulic]

i think im going to not use a dmm as my first way of seting my gain. i might see what it says when i get it all set.its just im sure when u go and turn stuff back on your deck the number u come up with will change.

Yes it most definitely will. The reasoning behind what they said was so that when you turned it all back on, your max volume would only be slightly more than where you set it thus only clipping your signal slightly and giving you a little less output. In reality, turning off bass enhancement settings in the HU etc that you're going to turn back on after setting is a bad thing because when you turn them back on, you either blow your amp or your sub. In my opinion, set it with the settings you use, but maybe one or two notches down from where you normally listen to it with the bass setting in your HU. This way, you can turn it up slightly more than where you set it but not much. That's how I do it.

They wanted you to turn your EQ off because if you set your gain at a frequency you've cut off a little, when you play a frequency that has no filtering, it will get way more power than it should. So I always recommend that people shut their EQ options off when setting the gain because of this. Leave your bass boosting adjustments very near where you play them.

 

[DidUHearThat? 10+ year member]

The problem is not the meter. You need a dummy load. You will get different readings with different loads. You need a dummy load that will replicate your target load, or at least give you a load you can calculate. 8 ohm dummy loads are common, and easy to find, and will allow you to calculate what you want at 8, and what it should be at 4 or 2 ohm or what ever your actual target nominal load will be.

You can either buy, borrow or build your own dummy load. Remember it's more important to be able to dissipate the heat for your target wattage than to actually hit your true target load. It will be easier to get/build a 200 watt 8 ohm dummy load, than to get/build a 1000 watt 1 ohm dummy load.

http://diyaudioprojects.com/Technical/DIY-Speaker-Dummy-Load/index.htm

http://www.audiokarma.org/forums/showthread.php?t=138902

http://www.radioshack.com/product/index.jsp?productId=2062288&cp=2032058.2032230.2032267&allCount=100&fbn=Type%2FPower+Resistors&f=PAD%2FProduct+Type%2FPower+Resistors&fbc=1&parentPage=family

 

[DidUHearThat? 10+ year member]

I own a Fluke True RMS meter, but the only real advantage it has is a very high impedence which allows for testing sensitive circuits without adding much of a load to the circuit your testing. That's it. Not at issue with this kind of a test. Other wise my 20 year old $15 RS digital meter works just as well for this kind of a test.