Stereo Questions

[nifty]

I've been lurking around this forum for a while now, and I've found quite a bit of useful information so thank you to everyone. I just took delivery of a Black 3.5SE w/CVT, no Bose or nav and Im having a blast driving it, (It's a small step up from a 1992 honda accord ) and now I have more questions about it that hopefully you kind folks can answer.

Im planning on getting a Kenwood DPX502 mostly due to its front USB port and Double Din size:http://www.crutchfield.com/App...PX502

In order to ensure its proper operation there need be a 4ohm impedance for each of its channels (according to a Crutchfield rep). From what I understand the front door 6.5 is a 2 ohm speaker. Is the tweeter 2 ohms as well? If that is the case I could wire the front door (Replacement with a kappa 6.5 2ohm) and the tweeter in series to achieve that 4 Ohm load. For the rear I could just find some 4 ohm 6x9's. I tried to check the tweeter with a multimeter but I was unable to get the grill off perhaps due to my fear of breaking it.

I did do a search but I could not find any of the answers I was looking for, so I apologize if this has been answered somewhere else. Thanks in advance!

[rjdmmfl1]

Nifty, In regards to the Kenwood, that's a great unit! I installed one of these in a friend of mine's vehicle and he loves it. I will say that if you are only looking for a cd player, and if you don't mind a single din unit, then the Pioneer P9800Bt unit with built in blue tooth and color graphics screen with ipod control for $375 from ebay, or you can get the one without color graphics for $100 less (DEH=p7900bt). Both units are superior to the Kenwood unit from my experience with the three!

In regards to the speakers, with the same headunit, going with 4ohm speakers with no inline amplifier will make your speakers sound a bit lower at a given volume level. The Kenwood has the same type of built in MOSFET amplifier as the pioneer units, so it will sound pretty good even if you go with 4 ohm speakers. BUt you DO NOT need 4 ohm speakers for that deck, you will hear better sound with 2 ohm speakers!

Also, DO NOT buy from crutchfield! They are overpriced. That same Kenwood unit can be purchased off ebay with a great extended warranty from a reputable powerseller for $100 less.

Use ebay, find a reputable electronics power seller, and buy everything from theat same seller. Then, send them an email and ask if you can have a 5% or 10% discount from them for buying multiple items. Tell them you've been offered as much from another dealer, and if they match it, you'll go with them. Also, ask them to give a combined shipping discount. Ding this can save you hundreds of dollars over crutchfield prices with a very similar warranty!

[audtatious]

You can't use 2ohm speakers with the HU as it is only 4ohm stable. 2ohm connections to the HU can (and eventually will) cause failure.

[nifty]

Thanks for the replies, its nice to know that someone has used the head unit with success.

You can't use 2ohm speakers with the HU as it is only 4ohm stable. 2ohm connections to the HU can (and eventually will) cause failure.

I was under this impression as well and I will make sure that it is using 4 ohms per channel to eliminate a premature failure problem (No offense rjd but I'd rather err on the side of caution). However that brings me back to the question of the tweeter impedance. If it is 2ohms, then I can just wire it in series with a 2ohm speaker in the front door. I just want to make sure that I have that 4 ohm load. I'll try my luck again today with getting them out and measuring them, if I find anything out Ill let you know.

Also, DO NOT buy from crutchfield! They are overpriced. That same Kenwood unit can be purchased off ebay with a great extended warranty from a reputable powerseller for $100 less.

Use ebay, find a reputable electronics power seller, and buy everything from theat same seller. Then, send them an email and ask if you can have a 5% or 10% discount from them for buying multiple items. Tell them you've been offered as much from another dealer, and if they match it, you'll go with them. Also, ask them to give a combined shipping discount. Ding this can save you hundreds of dollars over crutchfield prices with a very similar warranty!

It might be true that the CF unit is more expensive, but when ordering with them I would also receive the dash kit, wiring harness, antenna adapter, and I believe an iPod interface that is all included in that price. Nonetheless Ill do some checking into what you've suggested. Thanks for the help.

[rjdmmfl1]

You can't use 2ohm speakers with the HU as it is only 4ohm stable. 2ohm connections to the HU can (and eventually will) cause failure.

My friend has had his Kenwood DPX502 connected to 2ohm infinity Kappas for a while now, albeit his are connected through the RCA's into an amplifier. This setup is a little different as the amplifier can perform well with multiple resistance loads.

As for the unit, it is 4 -8 ohms stable, and attaching to 2 ohm speakers directly without an amplifier in between could cause damage to both the speakers and the headunit as audatious described.

I would say it is more likely you'll damage the speakers than the headunit, but that may be incorrect. I always advise folks to match their speakers/ woofers, amplifer up perfectly, and I don't think this should be an exception... in this regard, if you follow this line of thought you may have to replace your in dash speakers as I believe they are 2 ohms... or do as you have stated and wire them to the other speakers in series to get your 4 ohm load!

[rjdmmfl1]

It might be true that the CF unit is more expensive, but when ordering with them I would also receive the dash kit, wiring harness, antenna adapter, and I believe an iPod interface that is all included in that price. Nonetheless Ill do some checking into what you've suggested. Thanks for the help.

If indeed you will get the unit, dash kit, wiring harness, antenna adapter, and ipod interface for this price, then yes, it's a good deal, about the same as what you would get on ebay!

http://cgi.ebay.com/ebaymotors...ZWDVW

http://cgi.ebay.com/ebaymotors...wItem

[audtatious]

Damage would be to the headunit. Lower impedance = more heat.

[audtatious]

However that brings me back to the question of the tweeter impedance. If it is 2ohms, then I can just wire it in series with a 2ohm speaker in the front door. I just want to make sure that I have that 4 ohm load. I'll try my luck again today with getting them out and measuring them, if I find anything out Ill let you know.

Pull the tweeter and take a look at it. I know the Bose tweeter in my Maxima (Yeah, I know, it's a Maxima and not a Alty) was a Clariion 4ohm while the 6.5" mid was 2ohm.

[rjdmmfl1]

Damage would be to the headunit. Lower impedance = more heat.

similar to the way a 2 ohm stable amplifier would fry if going into a 1 ohm subwoofer load huh.. i gotcha, makes sense. I've just never seen it happen before, but as you pointed out, I guess if left long enough and played at high enough volumes, it will eventually!

[audtatious]

It could. The power ratings from HU's are total BS as well. In the case of using components with a HU that is rated 22w RMS then you have to consider that the mid and tweeter will be receiving 11wpc each at maximum volume. Internal amps are simply not as efficient as externals so the amount of distortion at those levels would suck pretty bad.

[rjdmmfl1]

It could. The power ratings from HU's are total BS as well. In the case of using components with a HU that is rated 22w RMS then you have to consider that the mid and tweeter will be receiving 11wpc each at maximum volume. Internal amps are simply not as efficient as externals so the amount of distortion at those levels would suck pretty bad.

you're 100% right. Ever turned a stereo up to max volume? At max volume the distortion is pretty awful (Except on Rockford Fosgate HU's, their headunits do not distort. They are the only ones that can make this claim!)

[nifty]

Pull the tweeter and take a look at it. I know the Bose tweeter in my Maxima (Yeah, I know, it's a Maxima and not a Alty) was a Clariion 4ohm while the 6.5" mid was 2ohm.

This is what I would like to do (pull and measure), but Im unable to pry up one of the four corners of the grill over the tweeter. Even after I do that I have a feeling that I'll need some special tools to take the actual tweeter out. So any help with either removing the tweeters or the resistance of them would be appreciated.

[rjdmmfl1]

when you say tweeter, do you mean the 3.5" speakers in the dash? I didn't have a problem pullin the grill up, it just pops out and snaps back into place. It feels like you might break it when you pull it, but it's ok, just gove it a tug.

Now to actually get the speaker out, you'll need a racthet type wrench because the windshield will prevent you from using a screwdriver.

[nifty]

when you say tweeter, do you mean the 3.5" speakers in the dash? I didn't have a problem pullin the grill up, it just pops out and snaps back into place. It feels like you might break it when you pull it, but it's ok, just gove it a tug.

Now to actually get the speaker out, you'll need a racthet type wrench because the windshield will prevent you from using a screwdriver.

Yes that is the speaker I was referring to when I said tweeter, I guess that could be kinda confusing. Anyway, I can pull up 3 corners easily enough, but one just wont seem to budge, I guess ill have to show it who's boss tonight.

I could tell even without it getting the grill off that the screws were going to be a pain. Ive been trying to find an offset screwdriver or a small enough ratchet to get the job done but I haven't found one yet. Maybe I should just call Nissan and talk to people until I find one who knows what the resistance of that tweeter is...

[nifty]

Ok, I now see why I have been having problems getting the grill pulled out. One edge of the grill is somehow attached under the front pillars and I am not quite sure how to take those out.

[nifty]

OK, Ive figured out how to get everything out properly, I just need to get the right tool to get the tweeter screws out. Once I do Ill post what I find out in terms of resistance just in case anyone else is wondering.