newbie audio help

stoogesrule · 02-23-2008, 08:10 AM

Hi, have the factory jbl system in my 91 XEB 2 door. I went to walmart and brought a sony cdx-gt420. ( it works.. just plugged in the two plugs). I'm thinking of buying 4 speakers (2 front, 2 side), they are infinity 6822 cf that chutchfield recommended and keeping the factory amp and sub. Would that amp power all those things? Does the amp power everything? Is the amp just for the sub? Are 91 jbl amps any good? If I keep amp how much bigger sub could amp handle? sorry for asking so many ?'s I just dont know. thanks

wickedklown · 02-23-2008, 10:00 AM

Well, im no pro, but i believe the first rule of thumb is that your amp should be a lower peak wattage than your subs. So if your subs are 1000wat peak with 800watt RMS - than your going to want an amp that pushes less than 1000watt peak. This is so that you dont blow your subs out.

As far as amps go, you can get a 4 chan amp which will power everything if needed. Most of your multi chan amps push HI and LOW signals, so you can use them for all speakers. For the subs its best to get a MONO ClassD, which only pushes the low signal for your subs. Honistly, if you just purchased an aftermarket head unit, you may like the sound from the stock speakers alot better, and may not need an amp to power them further. just get an amp to power your stock sub.

So the correct setup would be a 4chan for your tweets,mids, and then run a mono amp for your sub. However iv seen many people running everything from a multi-chan amp, so i know it is possible.

your going to want to look in the stickys, i belive someone posted the specs of the stock amp and subs. take a look at the specs for your sub, and then plan your amp purchase around that, Or look at the specs for the amp (which i believe is very weak) and plan your sub purchase around that. I do know your going to be looking for a 8in sub for replacement.

Im about to install a system in my X. Avic-d2 head unit, with a kenwood class-d 1800watt mono amp with 2x 12in 1900watt comp subs. I believe that the D2 will provide enough power to the tweets without the use of another external amp.

aznboi3644 · 02-23-2008, 10:37 AM

There is no rule of thumb about getting an amp that has less power output than the speakers can handle. Generally it is safer to select an amp that has 20% more power than the speakers RMS rating. Why? Amp levels can be set lower meaning a cleaner signal and less likely clipping...IF you know what you are doing.

Also there is nothing wrong with using a 4 channel or 2 channel amp for subwoofers. Say you have a 4 ohm subwoofer that you want to power it with 400 watts. It would be a smarter and cheaper choice to get a 2 channel amp that puts out 400+ watts bridged at 4 ohms. For a mono amp that does a real 400 watts at 4 ohms would cost a lot more.

Also people use 4 channels for every speaker in systems all the time bye using the front channels for the highs and bridging the rears for the sub.

You should be fine using the factory amp...they are pretty tough. If you want the best possible sound from the speakers the most critical thing you can do is dampen the door panels.

wickedklown · 02-23-2008, 10:42 AM

as i said, im not a pro. I just remember my installer telling me that on more than one occasion. I guess it all comes down to who your dealing with, and there personal recommendations.

stoogesrule · 02-23-2008, 01:54 PM

hi again, just returned from the boneyard. Found another 1st gen amp paid 10 bucks. my question is...could I run both of these amps? one for speakers, one for sub? seems to me the one amp I have in truck now is running speakers and sub. If I was to unplug wires to sub from 1st amp and splice the second amp into first amp (red and yellow wires) then plug in sub wires to 2nd amp? Would that work or is it a pipe dream and would just ruin what I have now. thanks

02-23-2008, 08:10 AM	#1
stoogesrule Wannabe Elite Explorer MD 1991 2 door eddie Join Date: Oct 2007 Posts: 14 Vehicle Specs (Original Poster)	newbie audio help Hi, have the factory jbl system in my 91 XEB 2 door. I went to walmart and brought a sony cdx-gt420. ( it works.. just plugged in the two plugs). I'm thinking of buying 4 speakers (2 front, 2 side), they are infinity 6822 cf that chutchfield recommended and keeping the factory amp and sub. Would that amp power all those things? Does the amp power everything? Is the amp just for the sub? Are 91 jbl amps any good? If I keep amp how much bigger sub could amp handle? sorry for asking so many ?'s I just dont know. thanks

02-23-2008, 01:54 PM	#5
stoogesrule Wannabe Elite Explorer MD 1991 2 door eddie Join Date: Oct 2007 Posts: 14 Vehicle Specs (Original Poster)	back from the yard hi again, just returned from the boneyard. Found another 1st gen amp paid 10 bucks. my question is...could I run both of these amps? one for speakers, one for sub? seems to me the one amp I have in truck now is running speakers and sub. If I was to unplug wires to sub from 1st amp and splice the second amp into first amp (red and yellow wires) then plug in sub wires to 2nd amp? Would that work or is it a pipe dream and would just ruin what I have now. thanks

02-23-2008, 10:00 AM	#2
wickedklown Wannabe Elite Explorer Join Date: Feb 2008 Posts: 20 Vehicle Specs	Well, im no pro, but i believe the first rule of thumb is that your amp should be a lower peak wattage than your subs. So if your subs are 1000wat peak with 800watt RMS - than your going to want an amp that pushes less than 1000watt peak. This is so that you dont blow your subs out. As far as amps go, you can get a 4 chan amp which will power everything if needed. Most of your multi chan amps push HI and LOW signals, so you can use them for all speakers. For the subs its best to get a MONO ClassD, which only pushes the low signal for your subs. Honistly, if you just purchased an aftermarket head unit, you may like the sound from the stock speakers alot better, and may not need an amp to power them further. just get an amp to power your stock sub. So the correct setup would be a 4chan for your tweets,mids, and then run a mono amp for your sub. However iv seen many people running everything from a multi-chan amp, so i know it is possible. your going to want to look in the stickys, i belive someone posted the specs of the stock amp and subs. take a look at the specs for your sub, and then plan your amp purchase around that, Or look at the specs for the amp (which i believe is very weak) and plan your sub purchase around that. I do know your going to be looking for a 8in sub for replacement. Im about to install a system in my X. Avic-d2 head unit, with a kenwood class-d 1800watt mono amp with 2x 12in 1900watt comp subs. I believe that the D2 will provide enough power to the tweets without the use of another external amp.

02-23-2008, 10:37 AM	#3
aznboi3644 Wannabe Elite Explorer Evansville, Indiana '98 XLT Join Date: Dec 2007 Posts: 950 Vehicle Specs	There is no rule of thumb about getting an amp that has less power output than the speakers can handle. Generally it is safer to select an amp that has 20% more power than the speakers RMS rating. Why? Amp levels can be set lower meaning a cleaner signal and less likely clipping...IF you know what you are doing. Also there is nothing wrong with using a 4 channel or 2 channel amp for subwoofers. Say you have a 4 ohm subwoofer that you want to power it with 400 watts. It would be a smarter and cheaper choice to get a 2 channel amp that puts out 400+ watts bridged at 4 ohms. For a mono amp that does a real 400 watts at 4 ohms would cost a lot more. Also people use 4 channels for every speaker in systems all the time bye using the front channels for the highs and bridging the rears for the sub. You should be fine using the factory amp...they are pretty tough. If you want the best possible sound from the speakers the most critical thing you can do is dampen the door panels.

02-23-2008, 10:42 AM	#4
wickedklown Wannabe Elite Explorer Join Date: Feb 2008 Posts: 20 Vehicle Specs	as i said, im not a pro. I just remember my installer telling me that on more than one occasion. I guess it all comes down to who your dealing with, and there personal recommendations.