Pioneer DEH P880

solacedagony · Post by **solacedagony** » Wed Nov 28, 2007 7:15 pm

kbakken wrote:Ha, I realized the date afterwards.
Each device doesn't know what each of the crossovers are on. And yes, it would apply that 12db at 80Hz slope twice. Once at the HU, and again at the amp. This doesn't mean, however, that it will double the effective rolloff to 24db/oct. It is totally redundant to have those two things set up the same like so. The eq curve is what it is. You can layer an infinite number of devices all rolling off at 80Hz and 12db/oct, and that's what the sound characteristics will be: 80Hz rolling of at 12db/oct.
As the sound signal goes through any of those devices, they will apply the same rules. They do not compound on each other. If one device does not see anything over the cutoff limit, then it just doesn't have anything to cut off.
Hope this helps.

Only there IS content over the "cutoff limit" or crossover point. Say you're using a 2nd order LR. Your signal is -3db at 80hz and -15db at 160hz. When you apply the second one, it's cascading on that last crossover. Now you're -6db at 80hz and -30db at 160hz.

The device doesn't "see" anything. It's like saying if you EQ your tweeter to -5db @ 80hz, it's not actually happening. Even if the signal at 160hz was down to -100db, it'd now be -112db. Just because you can't hear it doesn't mean it's not there. :happy055:

kbakken · Post by **kbakken** » Thu Nov 29, 2007 8:20 am

solacedagony wrote:Only there IS content over the "cutoff limit" or crossover point. Say you're using a 2nd order LR. Your signal is -3db at 80hz and -15db at 160hz. When you apply the second one, it's cascading on that last crossover. Now you're -6db at 80hz and -30db at 160hz.
The device doesn't "see" anything. It's like saying if you EQ your tweeter to -5db @ 80hz, it's not actually happening. Even if the signal at 160hz was down to -100db, it'd now be -112db. Just because you can't hear it doesn't mean it's not there. :happy055:

I'd hate to be so blunt, but you are wrong :) . Makes no sense. If you apply a rule with one device, and the same rule with another, it makes no sense that it would compound. "Just because you can't hear it doesn't mean it's not there"; if the HU cuts the signal (say low pass at 80Hz), then the amp doesn't "see" anything below 80Hz. The resulting music signal is now everything above 80Hz.

Also, try to understand that a frequency is a frequency. 80Hz is in the low-mid bass range (like part of a kick drum in a band). You mean to tell me that if you kept applying filters to it (of the same 80Hz cutoff), that you would eventually cut into the high sound of the guitars (around 500Hz and higher)? There's no way. Impossible. 80Hz is just that, 80Hz.

If you wanted to cutoff at 160Hz, then you would apply that rule to one of the devices. If you did it to the second one in line, this would effectively (what we hear) null the first one which is at 80Hz. But in terms of the audio signal, the first one cuts it at 80Hz, then the second one only sees the altered audio signal as everything above 80Hz, then cuts it at 160Hz. If you reverse the two where 160Hz is the first one and 80Hz is the second one: the first one cuts it at 160Hz, and the second one sees the altered music signal at everything above 160Hz. Therefore, the rule at the second one of 80Hz cutoff, would not effectively do anything to the audio signal since there is no 80Hz in the signal passed to it.

The same can be said for rolloff (slope). It does not add up in the end. It is what it is. If one rolls of at 3db/oct and the other at 12db/oct, the more extreme will be cut from the signal, and therefore be heard.

Graph out a frequency curve and overlap the two filters to see a graphical representation.

I like talking this kind of stuff. :)

solacedagony · Post by **solacedagony** » Thu Nov 29, 2007 9:42 am

kbakken wrote:I'd hate to be so blunt, but you are wrong :) . Makes no sense. If you apply a rule with one device, and the same rule with another, it makes no sense that it would compound. "Just because you can't hear it doesn't mean it's not there"]
That'd be a high pass for the amp to not receive content below 80hz, but it IS, in fact, receiving content below 80hz. 80hz itself would be down 3db from applying the crossover. If the crossover had a 12db slope, you'd lose 12dbs from that point every octave. So, using your scenario (HP @ 80hz/12db), 80hz = -3db, 40hz = -15db (Starting the 12db/oct drop), 20hz = -27db (Now -24db from the original 80hz). Crossovers aren't brickwall filters.
kbakken wrote:Also, try to understand that a frequency is a frequency. 80Hz is in the low-mid bass range (like part of a kick drum in a band). You mean to tell me that if you kept applying filters to it (of the same 80Hz cutoff), that you would eventually cut into the high sound of the guitars (around 500Hz and higher)? There's no way. Impossible. 80Hz is just that, 80Hz.
I'm not sure which part we misunderstood each other about but I'm not sure what you mean by that.
kbakken wrote:If you wanted to cutoff at 160Hz, then you would apply that rule to one of the devices. If you did it to the second one in line, this would effectively (what we hear) null the first one which is at 80Hz. But in terms of the audio signal, the first one cuts it at 80Hz, then the second one only sees the altered audio signal as everything above 80Hz, then cuts it at 160Hz. If you reverse the two where 160Hz is the first one and 80Hz is the second one: the first one cuts it at 160Hz, and the second one sees the altered music signal at everything above 160Hz. Therefore, the rule at the second one of 80Hz cutoff, would not effectively do anything to the audio signal since there is no 80Hz in the signal passed to it.
I think you're missing the part about the crossover not brickwalling. I can explain either scenario for you in terms of how it would electrically affect your signal.
kbakken wrote:The same can be said for rolloff (slope). It does not add up in the end. It is what it is. If one rolls of at 3db/oct and the other at 12db/oct, the more extreme will be cut from the signal, and therefore be heard.
BOTH will be affecting your signal. One just doesn't "disappear" magically :)
kbakken wrote:Graph out a frequency curve and overlap the two filters to see a graphical representation.
Sure, can do, except you should graph it twice in terms of signal path to really see what's happening. If your signal starts at the HU and there is a crossover in the HU, you graph that. When the signal gets to the amp with the active crossover in it, you already HAVE a modified (crossovered) signal so you need to subtract MORE from that.
kbakken wrote:I like talking this kind of stuff. :)

Me too and I very much respect the fact that we're both being civil and haven't resorted to name calling :happy055:

Bwcad1 · Post by **Bwcad1** » Thu Nov 29, 2007 10:42 am

stupid butt weasels! haha

solacedagony · Post by **solacedagony** » Thu Nov 29, 2007 11:03 am

Bwcad1 wrote:stupid butt weasels! haha

You love it Bill

kbakken · Post by **kbakken** » Thu Nov 29, 2007 11:56 am

Ah, touchee! Sorry man, I see the errors of my ways. Anything done to the signal by one device, is doing it to the signal passed on by the device before it in the line. I had to step back and think about it for a sec.

I'm not sure which part we misunderstood each other about but I'm not sure what you mean by that.

Me and my fast eyes and mind either missed or misread the part you said about 160Hz at -15db. :) I read it as the frequencies being added to make 160Hz, but I totally left out the -15db part. Makes more sense with that part in it.

I noticed from your site above that you play guitar. Nice gear! I have a Marshall 150W head, Behringer 4x12" Cab, effects, and ESP Kirk Hammett Custom Series KH-603.

Anyway, I think I will dink around with my car stereo some more. Just got the DEH-P880PRS a few days ago. So far, I likes what I sees.

Too friggin cold to any serious tuning, though.

My gear:
2005 Grand Prix, DEH-P880PRS, Concept 300W 4ch amp, 2x Morel Hybrid 6 Components (front and rear), Clarion APX 1000.2 amp, 2x Concept 12" dual voice coil subs, Tsunami 2.0F cap.

cargodz · Post by **cargodz** » Thu Nov 29, 2007 2:26 pm

Bwcad1 wrote:stupid butt weasels! haha

^ I'm with Bill... All this SQ talk is giving me a headache

LOL

solacedagony · Post by **solacedagony** » Sat Dec 01, 2007 3:09 pm

cargodz wrote:^ I'm with Bill... All this SQ talk is giving me a headache LOL

Just a little bit of theory to get the mind crankin along :)

cargodz · Post by **cargodz** » Sat Dec 01, 2007 4:59 pm

Yeah, but if it's loud enough you won't be in the car long enough to hear the difference between 36 and 36.15 hz

LOL

solacedagony · Post by **solacedagony** » Sat Dec 01, 2007 8:58 pm

cargodz wrote:Yeah, but if it's loud enough you won't be in the car long enough to hear the difference between 36 and 36.15 hz LOL

What'd you say??? :happy055: