# Good idea to power 1 pair of tweeters from new head unit? Hookup suggestions?



## demoncamber (May 22, 2013)

Ok so I did a little equipment refresh in my car after my head unit was stolen,
I have a monoblock D amp powering my 2 12's and an A/B 4 channel powering 4 coax, so I was thinking since I'm not using my head unit's amp at all, why not throw a pair of tweeters on there to help bring my sound stage up a bit higher. So can I safely power 1 pair of tweeters with the head unit's amp? Also does it make a difference in power if I connect 1 tweeter to front right and the other to rear left as opposed to just front right and left outputs? 

Details:
HU: JVC KD-X80BT @ 50W x 4 peak (20W RMS x 4 @4ohm, 200W total)
Tweeters: Kenwood KFC-ST01 @ 160W peak (40W RMS @4ohm)

Thanks!


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## Manic1! (May 17, 2011)

I say waste of time. What are you going to use as a crossover so your tweets don't try to play bass?


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## Bayboy (Dec 29, 2010)

passive xover.

Of course you can use deck power for tweets. Just keep them attenuated since you already have 4 coax. However, why use front & rear vs just front?


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## minbari (Mar 3, 2011)

Bayboy said:


> passive xover.
> 
> Of course you can use deck power for tweets. Just keep them attenuated since you already have 4 coax. H*owever, why use front & rear vs just front? *


x2. I would ditch the rear coax and just run the front with the extra tweeter. although, TBO you are gonna be well over any reasonable treble level. if you want to run a comp set, then get a comp set and ditch all the coaxs.

one other consideration, how much power do you have for the coaxs you have now? if you have something like a 100w x 4, then you will barely hear a tweeter at 20watts. gonna be hard to get the gain structure set up in any sensible way.


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## Bayboy (Dec 29, 2010)

Ha! Just realized my phone chopped off a bit of my earlier reply  starting to hate smartphones. 


Anyways, have you tried just listening to the coax alone? Depending on where they are it may not be worth adding a tweet unless you're upgrading to a component set..


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## syc0path (Jan 23, 2013)

minbari said:


> x2. I would ditch the rear coax and just run the front with the extra tweeter. although, TBO you are gonna be well over any reasonable treble level. if you want to run a comp set, then get a comp set and ditch all the coaxs.
> 
> one other consideration, how much power do you have for the coaxs you have now? if you have something like a 100w x 4, then you will barely hear a tweeter at 20watts. gonna be hard to get the gain structure set up in any sensible way.


I agree w/ all of this, except that at tweeter at 20W can still play pretty loud. 

The main problem I see w/ this setup is matching the volume level of the tweets w/ the rest of the system. The only control u have over the volume of the tweets is the volume control on the HU... which also controls the volume of the amped speakers. So what if u want to turn up the tweets while leaving the coaxes at the same volume level?


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## minbari (Mar 3, 2011)

syc0path said:


> I agree w/ all of this, except that at tweeter at 20W can still play pretty loud.
> 
> The main problem I see w/ this setup is matching the volume level of the tweets w/ the rest of the system. The only control u have over the volume of the tweets is the volume control on the HU... which also controls the volume of the amped speakers. So what if u want to turn up the tweets while leaving the coaxes at the same volume level?


you made my argument for me 

you will only get 20watts to them at 3/4+ volume. at normal volume you will get 5watts and trying to balance the rest of the system around a 5watt level on the tweeters will be nearly imposible.


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## syc0path (Jan 23, 2013)

minbari said:


> you made my argument for me
> 
> you will only get 20watts to them at 3/4+ volume. at normal volume you will get 5watts and trying to balance the rest of the system around a 5watt level on the tweeters will be nearly imposible.


Well as I said, I agree w/ almost your entire post. The only thing I disagreed w/ was what u said about not being able to hear the tweets. 

I think that if the main front stage was playing at 100W and tweeter was playing at 20W, the tweet would still be loud enough to make a difference and maybe even raise the soundstage like he's trying to do. The problem, as u and I have both mentioned, is that it would be very difficult to set the gains w/ the proposed setup so that the tweets and main front stage were playing at the desired volume level relative to each other.


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## demoncamber (May 22, 2013)

Well my 4 channel is an Audiobahn A4401T which is 4 Ohm Stereo : 50w x 2 and
2 Ohms Stereo : 70w x 2 (440w Max)

Fronts: Infinity Kappa 62.9I (75w RMS and 225w Peak) @2ohms
Rear: Alpine SPS-600 (80w RMS and 240w Peak) @ 4ohms

So I really don't want to put them on the 4 channel because I'm already pushing the amp as-is.

This is really just an experiment, as I will be testing it out today and tomorrow. If I have to I could get a 2 channel 100w amp.

I was asking about if it makes a difference on the HU if I wired one tweeter to front right and the other to rear left, because I was curious if I would get cleaner power, not sure if it's two amps in the HU, one for each: front and rear channel, or does it just share the entire load? Get it?

My rear coax are on the top rear deck and the fronts unfortunately are in the bottom front of the doors, it sounds good, but when you have two people in the car, your legs do block a bit of the highs and I find myself turning up the volume to compensate, so I figured if I mounted two tweeters up high aimed at head level, it would improve it entirely, even as just a fill. Obviously you can tell by now I'm going for SQ not SPL (although my two 12'' alpine type S @2ohms bump as loud as I can stand in a sealed box.. Dubstep sounds amazing )

Either way, I figured I would make out ok being as I'm only trying to power two tweeters on a HU that can handle 4 coax cleanly at mild volumes. Just assuming though.


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## minbari (Mar 3, 2011)

I cant beelive you need more treble with Kappas up front.


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## Bayboy (Dec 29, 2010)

minbari said:


> I cant beelive you need more treble with Kappas up front.


Bottom of the doors isn't always feasible even with bright sounding speakers. 

Tweeters up top will help, but I would run them off of the headunit's rears so you can at least balance them with the fronts through the HU. Then balance the rear deck speakers by turning the amp's gain down a tad. Should do ok.


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## gijoe (Mar 25, 2008)

Bayboy said:


> Bottom of the doors isn't always feasible even with bright sounding speakers.
> 
> Tweeters up top will help, but I would run them off of the headunit's rears so you can at least balance them with the fronts through the HU. Then balance the rear deck speakers by turning the amp's gain down a tad. Should do ok.


I agree, this seems like the best way to get things balanced, you'll have more control than if you you run the tweeters off of the front channels. Although, I don't necessarily think this is going to be a good idea either way, but it's worth a shot.


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## demoncamber (May 22, 2013)

That's a good point, as I'm only going to be using the Front and Sub pre-outs, so the rear channel wont be conflicting with anything coming off the HU... 
Good idea, didn't even think of that. 

I'm going to play it by ear  and see how it does with the speakers, it's cheap enough to pick up another low power 2 channel amp anyway, or maybe get a better quality 4 channel and just put the tweets in with the front channel.

It actually is pretty bright up front, but once I hit the -3db tweeter crossover button on the kappas, it's not so bad, the only thing saving me is that they are mounted low. I find myself in the winter hitting the -3 button because most driving is with windows closed, but in summer I drive with the windows down and need that extra 3db.

The Alpines have such a nice tweeter compared to the kappas..


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## demoncamber (May 22, 2013)

**update**

So for archival purposes of this thread, here's an update.

It worked. 

I think the thing that really saved me were the 4.8V preamp outputs. I didnt even have to do any fading or balancing from the HU at all. Coming from my previous HU, the gains on my 4 channel have been significantly lowered because of this. Pretty happy. I also mounted the tweeters aimed to head level just above my right and left end air vents. I'm hearing details that I've never heard before, not only that, the new kenwood tweets aren't harsh at all.

So, they blend quite nicely. I probably will some day get a better 4 channel amp when I decide to upgrade to a component system and do it right. But all in all, good deal. I no longer have to raise the volume to compensate for muffled highs.


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## Bayboy (Dec 29, 2010)

Glad that you have it all worked out. Just be careful in trying not to get that upgrade flu that tends to happen. Too often most (including me) will have things pretty good, try to attain that tiny bit you think is missing and wind up with a lateral or worse move. It happens more often than admitted.  

Basically, just enjoy the music until something goes wrong....


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## demoncamber (May 22, 2013)

I too know about the upgrade flu...

Realized one of my Alpine's tweeters are dead on the rear deck.... Got a good 5 years out of them though so not bad. Not that you can really tell anyway with the kappas and now kenwood's up front :laugh:

I never even knew about the majority of people against running any rear fill at all up until the other night while researching the tweeters... It makes sense though, I turned the rear channel down a bit now too. So maybe when I decide to replace the rear Alpines I'll get some mid bass 6.5's instead of coax or components in there.

Pretty surprised by this Audiobahn 4 channel though. Bought it used a few years ago, it's never let me down, actually pleasantly surprised.


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