posted
I really need to buy one of these, like real bad, hehe.
Anyways, i started looking at some and noticed that is has an input sensitivity rating on it, some say 1mv, some say 5mv.
Is this a spec to pay attention to when measuring headunit\amp(s)\EQ? If it is what should it be? Equal to the amps mv rating?!?!
Another quick question, when "probing" RCAs, how do you "probe" them. As, if the positive goes in left channel, where does the negative lead go?
And, where do you put the probing leads at on the amp?
And, i know that a lot of oscilloscopes allow and need someone to change the mv setting on the scope to accurately meter correctly, if i do buy an O-scope that requires that, how do i know what setting, when i'm using it, it needs to be set at?
posted
Input sensitivity will be the lowest Volatage/division setting on the scope. You can change the voltage per division and it will go up to around 10V/div. This spec is not something you need to pay attention to. I haven't seen a scope yet that wasn't capable of measuring what you need to set gains.
On RCAs the center of the RCA connector is positive, the shield around it is negative. On an amp the positive goes to postive and the negative to negative.
Most scopes allow you to change the V/div setting, but it's not hard. If you have it set too low the whole signal won't be visible on the screen, if you have it set too high the signal will be small and hard to see. It won't hurt anything if you have it set wrong, you just keep moving the dial until the signal is as big as possible on the screen.
Posts: 2575 | From: GA | Registered: May 1999
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posted
another thing, can clipping change with box design?
Liek if lets say we had 2 boxes for the same subwoofer- Both ported, one tuned to 30Hz, the other at 45hz
We go to set the system up with the box for 30hz and get ALL the frequencies from 30-80Hz on a good clean output using an EQ. If later on, we swapped it out with a ported box tuned to 45hz, would some frequencies begin to clip or even be allowed to turn up on the EQ higher?
posted
Tuned boxes are a dynamic structure - change 1 thing - change everything. So YES - it's a possibility. However, a little planning, and testing will show what needs adjusting to compensate.
Your cabinet design software should show any major problems in the box - the rest is just tuning, and tinkering until you have two setups that both work, and deliver different kinds of perfomance.
Posts: 9 | From: Hamilton, Ontario | Registered: Jan 2005
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posted
Yes on the amp output the + and - refer to the speaker leads, though I like to measure at the amp instead of the speaker wire to prevent shorting.
For what I was talking about the bow design won't change anything. We are talking about the clipping of the amp, the box tuning won't affect it.
Posts: 2575 | From: GA | Registered: May 1999
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posted
As for a box changing the distortion reading of an amplifier, of course they do. A box affects impedance, impedance affects output distortion, so a box affects output distortion.
To a significant degree? Amplifier distortion has very little impact on output sound until we're talking about "really" bad distortion, for subs up into the several percents, before that, the speaker produces much more distortion of the original input signal.
ShadowStar
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It's all about knowledge, love and respect. Posts: 2579 | From: Somewhere In the Northeast | Registered: May 1999
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posted
I'm sure it would be, you don't get quite the resolution with tose since the have a low res LCD screen, I think it's about the same as the TI graphing calcualtor I had in high school. But a small amount of clipping when you set gains isn't going to be a big problem, most people set their gains for some overlap anyway.
Posts: 2575 | From: GA | Registered: May 1999
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posted
WEll, fpr right now, i have just used it to setup a couple 6x9s on an amp running in high pass. I was clipping them as i seen before i adjusted some settings. I really need to hookup the EQ though as around 500hz, the waveform only takes up half the screen whereas around 10KHz it's fully on the screen.
When i get my new sub in a couple of weeks, i'll adjust my mono amp. Since mono amps are generally used to play a far lesser range of frequencies than a speaker set to HP, i shouldnt have that much problems maxin out the main frequencies during playback.
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