Kyblack76 Posted December 8, 2012 Report Share Posted December 8, 2012 (edited) Do you ever forum it out without being drunk? Serious question Me? HT ? No,.. no i dont... Ill buy next round... EDIT - Sorry if that post was outta line man.... lol.. Edited December 8, 2012 by KyLar96 Quote SMD SUPER SELLER The Burban Build Blazer Build sold Acura trunk build sold Link to comment Share on other sites More sharing options...
aps01 Posted December 8, 2012 Report Share Posted December 8, 2012 (edited) guys relax please...i am a competitor for many years here in greece i've seen a lot of things happening but vever have i seen such a huge increase in any car by just tuning gains on an amp...and just to make things straightso that i don't get flamed by one side or another,i tunned my amp by ear...i had no o-scope at the time but i'd love to have one or a dd-1 HV for setting my gains...i don't know if i'd get an even bigger dbdrag score than what i do right now or if i'd be a little lower but i don't think that i'd fall from 157 dbs to 150.5dbs because of a dd-1...that's my opinion...i'd also love to do a test with both an o scope and dd-1 but both on my car and with the term lab on and see what the results would be Edited December 8, 2012 by aps01 Quote '92 toy rolla EE90/AE92 1.3lt 12 x 8inch beyma (mids) 6 x beyma CP21-F tweeters(highs) 4 x 15 SPL Dynamics SPL380 D2(walled) 2 x ESX Vision 2500.2(mids,highs) 1 x SPL Dynamics D9-XS(subs) 4 x stinger SPV70 + 5 X SVR platinum 3500P batts 157.2 official on db drag comp-157.3 on same comp but eliminated...still a work in progress... Team Hxomania Trikala http://www.stevemeadedesigns.com/board/topic/156885-lil-noisy-toy-rolla/ Link to comment Share on other sites More sharing options...
TonyD'Amore Posted December 12, 2012 Report Share Posted December 12, 2012 The difference between when the DD-1 reads distortion and when it is visible by a human eye on a scope is fairly negligible, IF it is distortion caused by clipping. In terms of dB it would be within a couple of tenths, not 6.5dB, not even 1dB. If the distortion is caused by something other than clipping, there will be a huge difference between the DD-1 and a scope because scopes don't display distortion in a manner that a human eye would be able to read. If I had to make a guess about what happened here, assuming that everything was done correctly and everyone is being honest, I'd guess that the amplifier in question is dirty to the point that it is over 1% THD wayyyy before clipping. This is what the DD-1 saw, thus it said "hey I see excessive distortion". It is up to the operator of the device to determine the source of said distortion. When used to set gain, if you start with the gain down and the correct overlap track and the DD-1 reads the signal as clean, and then one proceeds to turn up the gain until the distortion LED illuminates you are pretty guaranteed that the distortion it is reading is due to clipping and you have now set the gain properly. HOWEVER, there are some seriously dirty noisy ass class D amplifiers on the market these days, and the DD-1 will call them out every time. The DD-1 is pretty amazing, but it's not magic or psychic. If this were happening in my install, I would check the signal from the front to the rear making sure everything stays distortion free throughout the entire range of the volume control (up until the point where we know the source distorts). If that the signal is clean all the way through the volume range, but distorted at the amplifier intermittently or continuously throughout the volume range, then we know exactly where the problem lies. Without seeing any of what happened first hand, this is my best guess. 1 Quote Link to comment Share on other sites More sharing options...
TonyD'Amore Posted December 12, 2012 Report Share Posted December 12, 2012 (edited) Um, if i am understanding THD correctly, then the DD-1 must have an internal filter,(like a 39.99hz to 40.01hz, and one similar for 1k. It samples both what goes through the filter and also samples what does not. So once whatever does not go through the filter is above .99% of the total signal it lights up the distortion light. Or am i way off here. That could possibly create a situation where if for some reason you were processing the signal and it was effecting 40hz, the dd-1 would show distortion sooner. Because on an o-scope you would just see a waveform, and not notice if the frequency shifted. edit: i mean the user may not notice an effected(sp) signal You aren't too far off, but in your example of 40Hz, everything that is in the signal that ISN'T 40Hz isn't harmonic distortion, it is just noise. So removing the 40Hz signal and measuring what is left over isn't measuring harmonic distortion, it is measuring noise. Harmonic distortions happen at precise frequencies, so in the case of the DD-1 it has to measure the fundamental frequenices, and the harmonic frequencies (at the same damn time), then compare the ratio of the amplitude of these things. Edited December 12, 2012 by TonyD'Amore Quote Link to comment Share on other sites More sharing options...
wcefai Posted December 12, 2012 Report Share Posted December 12, 2012 It always seems that Tony D and Snafu take me to school when it comes to car audio lol Also, great vid CJ! I'm glad that people like you take the time to post stuff up like this Quote Link to comment Share on other sites More sharing options...
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