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View Full Version : Just ordered my first set of comps.. wattage question.



Camer138
12-04-2011, 09:03 PM
Yesterday I got my head unit installed, thats the Kenwood 348u, and I just ordered some JBL p660c component speakers on ebay for a pretty good price. These are going n the front and I'll likely get some cheaper coaxials in the back like the Pioneer td-d1602r's..

I haven't quite figured my amp out yet though as the one I've been looking at most(jbl gto1004) seems like it might be too much wattage for these speakers..

the P660c's are 90w rms at 2 ohms where the amp gives 150w rms at 2 ohms

the ts-d1602r's are 60w rms at 4 ohms where the amp gives 100w at 4 ohms..

should I get a weaker amp? will this blow the speakers at louder volumes? and am I able to wire 1 channel from the amp to power both rear speakers so the power is split in half? I'm completely new to this so forgive any newb questions. thanks!

keep_hope_alive
12-05-2011, 12:03 AM
You need to wire one speaker pre channel. Your HU has 3 sets of preouts, you will run two sets to a 4 channel amp.

Power is not constant, but varies based on head unit volume and amp gain setting. You can give less power to rear speakers by simply turning down the gain.

Bettr n' Revrse
12-05-2011, 12:08 AM
You need to wire one speaker pre channel. Your HU has 3 sets of preouts, you will run two sets to a 4 channel amp.

Power is not constant, but varies based on head unit volume and amp gain setting. You can give less power to rear speakers by simply turning down the gain.

Yep

Why So Cereal?
12-05-2011, 12:33 AM
Yep

x2

zako
12-05-2011, 05:04 AM
Speaker wattage ratings are quite meaningless. Most of the time they are thermal. However, if your high pass crossover is low enough, your "100watt speaker" could be bottomed out with only 50watts per channel. The bottom line is do not read too much into speaker specs. Clean 50-70watts RMS per channel or more is enough for most speakers.

Camer138
12-05-2011, 10:18 AM
thanks guys..

and I'm curious.. do manuals explain how to set crossovers well or do the installers usually set it up for you?

zako
12-05-2011, 01:26 PM
thanks guys..

and I'm curious.. do manuals explain how to set crossovers well or do the installers usually set it up for you?

Try to play them full range mode with a starting crossover setting, e.g. 70Hz, possibly with the sub off. If you can hear them get harsh and lose their composure when stronger drums kick on some recording, bump up the crossover frequency by 10Hz, repeat. For a 6.5 speaker, 70Hz is a good starting point.

VWBobby
12-05-2011, 01:40 PM
If your amp has a built in HPF, try engaging it and see if they keep their composure at louder volumes. Most on-board HPF's are around 80hz and 12db/oct....combined with a sub LPF'd at 60-80hz, they blend pretty nicely (if you have a sub?). Edit: that amp has a variable HPF, you can dial it in until it sounds good to you. I tune at the amp side usually and fine tune at the head unit (eq).