Help me connect 4 ch amp, 4 speakers and a sub


r3hab

CarAudio.com Newbie
May 7, 2019
7
0
Hello,

My current equipment has no SW - Kenwood 6405 amp (4x40 or 2x130 at 4 ohm); 4 Morel speakers connected to the amp (110; 120rms) and Pioneer AVH 3300BT.

I'm thinking about adding a 150 RMS Hertz sub with minimal cost (money/space/effort), just to fill the lows a bit. My current idea is:

The head unit has 6 RCA (2 fronts, 2 rears and sub L/R), currently 4 of them connected. Can I leave my fronts connected to the amp, wire my rears to the head unit instead and bridge the freed 2 ch on the amp for the sub (using the already installed rear RCA and just moving them to SW RCA on the head unit? (attached image with my connection idea)

Car audio setup.png

 

Boomin_tahoe

Hurtin' feelings errrday.
10+ year member
Jul 24, 2005
15,678
250
WA
Nope. Not the proper way of doing that. Power the speakers with the 4 ch amp and give the sub it's own amp power. Or find a good 5 ch amp and then you can power all your speakers and sub from it. I have a 5 ch amp right now, and have had a few in the past.

 
OP
R

r3hab

CarAudio.com Newbie
May 7, 2019
7
0
Yes it will be the best and most proper way, but I have to invest a lot more, since 5 ch amps are expensive and and it appears there aren't many used in my country (for reference, I'm thinking about HERTZ DBX 25.3 sub, which converted from my currency is around 90$ and the cheapest 5 ch amp is Hertz HCP 5D for 324$ converted). I thought about a second mono amp, but additional wiring to the battery and space in the trunk sets me off a bit. I will try to find a decent cheaper 5 ch amp, but there isn't much availability here and to spend nearly 4 times the price of the sub for a new amp just isn't cost-effective..

Still, thanks for your response.

 

Coolhand20th

CarAudio.com VIP
Mar 27, 2019
264
59
Wisconsin
You don't need additional wiring to wire a second amp, idk who or where you came up with that but that isn't true at all. You use distribution blocks for your ground and power wire as shown below in the picture of my current setup.

amp install 2003 ford.jpg

 

Boomin_tahoe

Hurtin' feelings errrday.
10+ year member
Jul 24, 2005
15,678
250
WA
Yes it will be the best and most proper way, but I have to invest a lot more, since 5 ch amps are expensive and and it appears there aren't many used in my country (for reference, I'm thinking about HERTZ DBX 25.3 sub, which converted from my currency is around 90$ and the cheapest 5 ch amp is Hertz HCP 5D for 324$ converted). I thought about a second mono amp, but additional wiring to the battery and space in the trunk sets me off a bit. I will try to find a decent cheaper 5 ch amp, but there isn't much availability here and to spend nearly 4 times the price of the sub for a new amp just isn't cost-effective..

Still, thanks for your response.
No don't do it. Your gonna have a hard time making all that try and sound good. Subs are NOT meant to be powered from a 4 ch amp. So what if you have to "invest" more...welcome to car audio. Your an idiot if you actually go this route.

 

Jeffdachef

Gunz That Turn on Nunz
Feb 5, 2013
18,232
677
South Coast Metro, CA
your idea only works if your amp has a good enough low pass filter and even then, your sound is going to be weak as sh*t so adjust your expectations accordingly.

 
OP
R

r3hab

CarAudio.com Newbie
May 7, 2019
7
0
You don't need additional wiring to wire a second amp, idk who or where you came up with that but that isn't true at all. You use distribution blocks for your ground and power wire as shown below in the picture of my current setup.

View attachment 5311
So i get a mono amp and those blocks and do I need to change the fuse on the front of this power cable or can I leave it as it is?

Thank you!

 

Coolhand20th

CarAudio.com VIP
Mar 27, 2019
264
59
Wisconsin
Leave it as is and if you look at my power distribution block it also has 2 fuses one for each amp. I have 100 amp fuses in the block and in the one at the battery.

 
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r3hab

CarAudio.com Newbie
May 7, 2019
7
0
Okay, thanks, I will research this route more - it's definitely less expensive than a 5 ch amp, a bit of a clutter for a hatchback trunk, but I'll think about it some more.

 
OP
R

r3hab

CarAudio.com Newbie
May 7, 2019
7
0
What about the signal sensing (turn on when head unit powers on). I need to split this one too. Is there something important about the way to do it?

 

Coolhand20th

CarAudio.com VIP
Mar 27, 2019
264
59
Wisconsin
Look at the blue wire in the picture. I used speedwire that has all 9 wires in it, 8 speaker wires for all 4 speakers and then a blue remote turn on wire. What I did was split it off to the two amps. Split it off or run another wire from the head unit. If you are running new speaker wire then get 20ft of speedwire as that is how it is sold on eBay and cut to the length you need and do it as I described.

 
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n2audio

OPTIDRIVEN
10+ year member
Dec 29, 2001
5,697
66
Lawrence, KS
What you want to do is PERFECTLY fine.  At WORST, it is a step in the right direction.

There is NOTHING bad about using 2 channels of a 4 ch to run a sub -- it has a low pass filter and will work fine.  Actually, it's probably the best way to build a decent sounding system at minimal cost.

Some of these know-it-all's don't realize mono/subwoofer amps just came to the market about 20 yrs ago.   People were putting together perfectly good quality sub setups with their bridged multi-channel amps LONG before mono/subwoofer amps were developed -- some still prefer them. 

At <200w you're obviously not going to have the LOUDEST sound around, but it will sound fine at moderate volume.

Don't let all these car audio holier than thou geeks tell you what you want to do is dumb.

Next step -- save for a decent sub amp and bridge the Kenwood to give your fronts more power.  That will allow you to kick the volume up a bit and still have good sound quality.

 
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Coolhand20th

CarAudio.com VIP
Mar 27, 2019
264
59
Wisconsin
Wow gotta love all the name calling in the post above me! And mono blocks were around long before 20 years ago,lol. Try 1964 when the first Class D amplifier was sold to the public by Sinclair Radionics. Even back in the 1980s they were abundant for sale to the public. So before you spot off about how we know nothing try a little research. Even my dad laughed at your comment because he was using Class D mono amps back in the 1970s, were they expensive well duh but they were available to the public.

 

Boomin_tahoe

Hurtin' feelings errrday.
10+ year member
Jul 24, 2005
15,678
250
WA
What you want to do is PERFECTLY fine.  At WORST, it is a step in the right direction.

There is NOTHING bad about using 2 channels of a 4 ch to run a sub -- it has a low pass filter and will work fine.  Actually, it's probably the best way to build a decent sounding system at minimal cost.

Some of these know-it-all's don't realize mono/subwoofer amps just came to the market about 20 yrs ago.   People were putting together perfectly good quality sub setups with their bridged multi-channel amps LONG before mono/subwoofer amps were developed -- some still prefer them. 

At <200w you're obviously not going to have the LOUDEST sound around, but it will sound fine at moderate volume.

Don't let all these car audio holier than thou geeks tell you what you want to do is dumb.

Next step -- save for a decent sub amp and bridge the Kenwood to give your fronts more power.  That will allow you to kick the volume up a bit and still have good sound quality.
Way to encourage the OP. This sorta thing might have been cool to do back in the 90's or so but nowadays the BEST route to go is simply another amp separate for his sub only or a 5 ch amp. Did you not read what Jeff said?? The amp is not gonna filter out any unwanted freq if he were to run a sub off it. Terrible idea at best.  I don't see ANYBODY doing this at all. So many amps on the market there's really no need to.

Yup, we know it alls know what we're talking about. Funny how newbies come to this forum "knowing" that us veterns are still around seeking the proper help needed.

OP...sell that 4 ch amp and buy a 5 ch amp. Or just save a little more $$ and buy a small mono amp for the sub.

 
OP
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r3hab

CarAudio.com Newbie
May 7, 2019
7
0
OK, I'll go with the amp route (5ch or second mono). I have a new questions about setting everything up.

On my pioneer head unit in the settings I have High pass filter (50/64/80/100/125) and in the subwooofer tab I have Phase, Level and Frequency (again 50/63/80/100/125).

Should I use the settings in the player to set the frequency response of the speakers and sub or should I use the filters on the amp/amps or some combination?

It's easier on my AVR at home, just setting a crossover of 80hz and that's it. Also what crossover frequencies do you use in your cars? Is the "magical" 80hz also appliable in cars, or maybe lower is better, because you can localize the sub in the trunk on higher frequencies?

These are the spec of my current amp Kenwood 6406 and the filters it has:

Kenwood 4ch amp.png

 
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n2audio

OPTIDRIVEN
10+ year member
Dec 29, 2001
5,697
66
Lawrence, KS
Wow gotta love all the name calling in the post above me! And mono blocks were around long before 20 years ago,lol. Try 1964 when the first Class D amplifier was sold to the public by Sinclair Radionics. Even back in the 1980s they were abundant for sale to the public. So before you spot off about how we know nothing try a little research. Even my dad laughed at your comment because he was using Class D mono amps back in the 1970s, were they expensive well duh but they were available to the public.
Name calling?  Is this your first day with internet access?  Know-it-all, holier than thou, and geeks are relatively friendly references for the 95% of people on here who don't believe in a difference of opinion.

You can bring out all the obscure history references you want.  12v sub amps were not common before '00.  I was there, shopping and researching tech forums -- not single minded bromo nut-hugging forums like this one.  That's all beside the point anyway -- which was there is never a NEED for a sub amp.

The guy wanted a cheap solution, and the one he was considering was perfectly logical and effective.

Way to encourage the OP. This sorta thing might have been cool to do back in the 90's or so but nowadays the BEST route to go is simply another amp separate for his sub only or a 5 ch amp. Did you not read what Jeff said?? The amp is not gonna filter out any unwanted freq if he were to run a sub off it. Terrible idea at best.  I don't see ANYBODY doing this at all. So many amps on the market there's really no need to.

Yup, we know it alls know what we're talking about. Funny how newbies come to this forum "knowing" that us veterns are still around seeking the proper help needed.

OP...sell that 4 ch amp and buy a 5 ch amp. Or just save a little more $$ and buy a small mono amp for the sub.
Did I read what Jeff said?  Yes, I did, and he's wrong -- which is why I pointed that out.  It has an LPF, it took, I don't know, 10 sec to verify that.

I encouraged the OP because it is sound and logical advice.  The BEST solution?  No.

The BEST solution is to save up a couple grand and do something outstanding, but that's not the budget and that's not the goal.  A couple things a lot of people here are unwilling to consider.

Buy the sub, provide a good enclosure, bridge the kenwood.  Everything will work perfectly fine with no problems whatsoever.  That is a fact and it can't be argued.  Will it be the greatest sounding setup in the history of all things car audio -- sadly, no, it won't.  But, it won't be money wasted, it won't be back tracking, it won't be anything negative, it will simply be the cheapest, shortest-term solution.  Which is the correct answer to this question.

If OP WANTS to spend more money on a 2nd/better amp --- great, that is an option too.  Doesn't have to happen now.  Doesn't have to happen ever.

There is EVERY possibility he may be happy with just the addition of a little bass.

You guys need to get over yourselves.

 
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Coolhand20th

CarAudio.com VIP
Mar 27, 2019
264
59
Wisconsin
Lmfao my first day..I was on the internet back in the 1980s, not the modern internet but there was all sorts of people on it back then. Thankfully I had a father who built his own computers and taught me stuff that wasn't common until the 1990s. And yes they were very common before 2000. Obscure history references? No try facts there slick. I had a 12v mono block in my '92 S-10 back in '95. So just stop with the garbage about it not being around. Just because you were not able to find it doesn't mean the rest of us didn't, especially south of Chicago where they were commonplace dating back to as I said when my dad was using them in the '70s.

He can do something now for cheap that will work just fine, especially with what they cost these days. Taramps ship from Brazil to all over the world regardless of country. No middle men and are rock solid and put out waaaaay more then what they advertise, plus the quality is there as well for next to nothing.

 
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