Setting crossover and subsonic with DD-1 still connected

[Real96SS]

So I have been trying different way to tune with the DD-1 and the manual tells you to set the LPF all the way up and subsonic all the way down before tuning.Anybody know why even though it says you can set them where you want afterwards? So I tried adjusting these with the DD-1 still connected and noticed that the amp starts to clip depending on where I set the two.So has anybody else tried this or know why the manual doesn't tell you to set them before you disconnect the DD-1 to make sure its not clipping?

[Lbox88]

From my understanding, it is because the DD-1 does not test for clipping, it tests for total harmonic distortion. Decaf has some pics of what I mean, maybe he can step in here. The difference would be though, if you start to distort at a frequency, you see smaller peaks of different frequencies both higher and lower, on a spectrum analyzer. If you set your LPF, SF, and any other filters first, those filters may block the appearance of those frequency spikes when you are experiencing distortion, thus masking the problem till you increase the gain even more. The distortion would basically be there, but you & the DD-1 would not see it due to the filters. Does that help?

People > I, if I am wrong let me know so I can delete/modify the above.

Edited January 13, 2012 by Lbox88

[Real96SS]

Yeah that helps.I went out to do some more testing and now the DD-1 doesn't even pickup a signal on my subwoofer rca's. I even went straight to the deck and used a different pair of rca's and still nothing. When I connect them to the amp it works fine though. Don't know what happen why it stopped picking up the signal from the deck.

[Lbox88]

I found on mine (Pioneer DEH-6300UB) on the RCA out, I had to go to volume 54ish to even detect and would clip at 61. Little 2V outputs. You can hook up to a HU Speaker output and test there to make sure it still works. I will add the link to my help page too to show what all I did.

EDIT: Here

Edited January 13, 2012 by Lbox88

[Real96SS]

Okay I'm going out to test through the headunit speaker output to see what happens.

[Real96SS]

So testing through the speaker outputs on the deck it works fine.Only thing I noticed is that it distorts at 35 which is max where as through the front and rear RCA's it doesn't distort. So knowing that the front and rear rca's work fine it's just the subwoofer outs that don't does this cause a problem or do the rca's need to be grounded?

[Decaf]

few things to mention

if the ssf goes past 40hz and you are turning it past then, you are starting to use the amps crossover. the dd-1 is picking up "noise" is my guess, that's not clipping.

i have not had 1 rca that fit on the top of the unit and worked, this is not because the dd-1 is faulty, simply the shape or depth or ground shield did not meet up. so i have always just used the amp to test the headunit.

your headunits internal amplifier will almost always clip/distort before the max undistorted rca volume. when you are testing the headunits speaker leads you are basically testing the gain of the headunits amplifier, the gain knob being the volume knob. its always best to NOT use the headunit to power any speaker for that reason, and to eliminate sources of heat

[Real96SS]

SO I shouldn't worry about the dd-1 not picking up a signal from the subwoofer rca's? If that's the case then I will just check it through the amp tomorrow because it's dark out now.

[Decaf]

SO I shouldn't worry about the dd-1 not picking up a signal from the subwoofer rca's? If that's the case then I will just check it through the amp tomorrow because it's dark out now.

nope, no worries. some rcas just dont go down far enough into the unit

for me, its easier to check the headunit thru the amp you are about to set gains on. all you do is play track 1/2, find max undistorted volume, then play track 3/4, 5/6, 7/8 and turn gain up. no probes were moved, no rcas to fiddle with... less than 1 minute to set gains and headunit

[Real96SS]

Cool thanks.Will let you know how it goes tomorrow.