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View Full Version : lots of Q's regarding pioneer 7800 (time alignment, adjusting source levels, etc.)



frankiebones
12-04-2006, 10:21 AM
i started a thread yesterday re: bridging my 4 channel kicker to power my morel comps. with the pioneer HU i have, you dont get anywhere near the 5V preamp output until u get to around volume 50/62.

without meaning to, i kept on turning down the front ouput a few decibels just until i got a feel for what the speakers could handle before distorting or (knock on wood) blowing sky high.

so now, i listen to the system at a maximum volume of 50/62, but when i do so, the output level for the front output (which is split using y adaptors to the 4 channels) is set at around -3.

should i use my DMM and retune with the gains set at a lower voltage? i dont care what number i get from the sqrt [imped. x rms], if theres distortion, its too high and almost certainly clipping.

i was kinda thinking that by setting the front output level down a few notches, it would allow me to turn the volume up higher, and thus get a stronger preamp output but that makes no sense bc if i am decreasing the output level, im decreasing the output voltage, right?

i have been in the law school library for 17 hours, so if this post is all over the place, its not my fault, its that **** ritalin.

also, i must confess one more thing: the feature the HU has that allows you to adjust source levels (SLA), what is it? should i use it?

i also am having a hell of a time getting the time alignment settings correct. at first i thought it was bc i have slight hearing loss in my left ear from playing drums so long, but then i had 2 other people sit in the drivers seat and they said that with the time alignment on, it was making them dizzy!

i measured the inches from my ear to ear tweeter position, from what i have been told, mids are not directional, or not nearly as directional as highs.

lot of crap shoved into one post so if u only know the answer to one of the 20 questions i posed, dont be shy now.

rock and roll,

-frankie f*ckin bones

pwnt by pat
12-04-2006, 10:31 AM
Leave the "eq" at 0 and fine tune level mismatches with the gain. If you need to boost certain frequencies (high, mid, low), change the frequencies and then reset the gain.

don't worry so much about what preamp voltage your amps are seeing. It's irreivant anyway. All that matters is the gain is set correctly.

SLA changes the volume reference levels of the different sources, radio, CD, changer, etc so you can make their volumes all the same. It's so you don't have to crank the volume up to listen to the radio, then turn it down to listen to a CD.

frankiebones
12-04-2006, 10:37 AM
Leave the "eq" at 0 and fine tune level mismatches with the gain. If you need to boost certain frequencies (high, mid, low), change the frequencies and then reset the gain.

don't worry so much about what preamp voltage your amps are seeing. It's irreivant anyway. All that matters is the gain is set correctly.

SLA changes the volume reference levels of the different sources, radio, CD, changer, etc so you can make their volumes all the same. It's so you don't have to crank the volume up to listen to the radio, then turn it down to listen to a CD.

wow, you gave a tough question (from my end) a really concise and simple answer....good sh*t.

however, when u say "level mismatches," u mean between the diff drivers, i.e., when the gains on both amps are set appropriately, the components drown out the sub or vice versa?:uhoh:

also, are you saying that when i use a DMM to set voltage, i should do so with whatever EQ cuts/boosts, processing turned on, and that any change i make in terms of sound processing should end up with me using a test tone and retuning the gains to the correct voltage?:uhoh:

pwnt by pat
12-04-2006, 11:09 AM
level mismatches, I adjusting output levels to compensate for, say, an overpowered substage. You do this by setting all your gains to right before amplifier clipping, then turning down the gain on the piece of equipment that's overemphasized.

For the gain, start with a reference gain that you know is under clipping - IE, set it to just below unclipped and then turn it down a good bit. Then do all of your processing, crossovers, eq, etc. Then set your gain to max unclipped. Then level match. Then eq the crossover areas.

( When you eq, do each piece individually within their passband. If your mids play 80hz to 2.3khz, then eq between 80 and 2.3khz on the mids. )

That's how I do it. What can happen is if you set your gain before doing any frequency boosting, and you don't turn the gain down on that amp when level matching, at those boosted frequencies, there's a chance you'll run into clipping.

Personally, I'll take a hit in output vs a clean signal.

lincolnls
12-04-2006, 11:18 AM
you should be able to keep the output of the rca's up and still have a clean signal.

do you have any other processing gear betweent he head unit and the amp? just making sure im not missing anything here.

although my experience with my pioneer head unit was only good for about 3 volts of preamp rca before sounding like s**t. so i see what you are saying


again are you using a DMM or a RMS DMM. if you are using a DMM you should be using a 60hz tone as the regular DMM is set to read voltages at 60HZ, a RMS DMM will be able to detect the freq of the power and give you an accurate result so no need to use a specifc tone

frankiebones
12-04-2006, 11:33 AM
Personally, I'll take a hit in output vs a clean signal.

amen

frankiebones
12-04-2006, 11:34 AM
you should be able to keep the output of the rca's up and still have a clean signal.

do you have any other processing gear betweent he head unit and the amp? just making sure im not missing anything here.

although my experience with my pioneer head unit was only good for about 3 volts of preamp rca before sounding like s**t. so i see what you are saying


again are you using a DMM or a RMS DMM. if you are using a DMM you should be using a 60hz tone as the regular DMM is set to read voltages at 60HZ, a RMS DMM will be able to detect the freq of the power and give you an accurate result so no need to use a specifc tone


i dont think its an rms dmm, does that mean that the 1kHz tone i used when setting the amp for the mids and tweets was very inaccurate?. ill get the model number in a few min when i go out to my car, thanks though