amp and sub settings question

Ray Zenz

alright a couple of quick questions..im not sure if you guys remember one of my previous posts but i have the underpowered Orion H2 and i have finally got a box for it. I have decided to keep my amp for now which is a Kenwood KAC-7202. And it sounds good with the amp but i have a few settings questions. There is the bass boost setting of course, if this is turned up will this be sending a bad or distorted bass frequency to the sub or can this harm the amp if turned up high. I also like to run the amp with the low pass filter off. Any problems with that? And there is also a input sensitivity setting, and when turned up this can really put out the bass but it also seems to get distored a little. Any suggestions?

Also this is the first time i have my amp bridged, this may be the reason its running a little hotter than usuall. But i think there might be a problem with the ohms but i think im right. This is a dual voice coil sub. And it is stable at 2 ohms each coil. One "-" from a voice coil is goin to the "+" on another. Then a "+" is goin to the "+" bridged on my amp then the unused "-" goes to the "-" bridged on my amp. The amp says that when bridged it has a 4 ohm load. So when connected to a DVC sub then dont the ohms split up and 2 ohms go to each voice coil?

im a little confused, thanks guys

Greg Peters

Ray Zenz wrote:

There is the bass boost setting of course, if this is turned up will this be sending a bad or distorted bass frequency to the sub or can this harm the amp if turned up high. I also like to run the amp with the low pass filter off. Any problems with that? And there is also a input sensitivity setting, and when turned up this can really put out the bass but it also seems to get distored a little.

The bass boost setting- don't crank that up too high, a little should be OK if you find you need some more output at a certain frequency.

Low pass filter off? Your sub won't play the higher frequencies too well (and if you have it trying to play "full range" above say 100-200hz, you'll be wasting amplifier power on those frequencies your sub can't play well). There is really no point in trying to have your sub play too high a frequency, plus it will help your ears localize placement of the sub rather than have it's output blend with your other speakers. Do use the low pass filter and set around 100hz. If output is too boomy, lower to around 80hz. This will help your amp to concentrate on playing only frequencies useful to your subwoofer and will probably get you a bit more lower bass output than you have now.

Input sensitivity- if turned all the way, you will get some distortion (and your amp will be working its hardest). Turn it to where you get the highest clean output from your subwoofer and leave it there to minimize problems like putting that amp into protection mode.

Your Kenwood KAC 7202 should only be stable to 4 ohms bridged. If your sub has dual 2 ohm voice coils, one way to hook it up would be simply to wire each voice coil to a single channel (not bridged) of the amp so each channel sees a 2 ohm load. It looks like it's rated for 150 watts x 2 @ 4ohms but is 2 ohm stable when not bridged, so if you were to wire each channel to one 2 ohm voice coil you could expect around 230 watts to each voice coil without burning up your amplifier (provided gains for L and R are set the same).

If you prefer to bridge your amp, wire + from one voice coil to + on amp and then run - to the + terminal of other voice coil. Finally, wire - of other voice coil to - on amp (for a total of 4 ohms) which I believe is how you have it wired right now (and should give you 460 watts mono).

Either way should keep your amp happy until you can get something that makes better use of your sub.

Ray Zenz

wow thanks greg, ya i found that when the input sensitvity (which i assume is the gain control) was turned up, it got distored. Now my low pass filter is on and the bass isnt "cleaner" but its a whole lot louder and it doesnt try to hit the high notes. I am keeping an eye out for another amp..any suggestions, otherwise i might buy another kac 7202 because i can get the best buy employees dscount on it..

Greg Peters

Well, it would depend on your budget.

If your Best Buy has the Alpine V12 Class D monoblocks (MRD-M605, MRD-M1005) they might be worth finding out what staff pricing is like on. You could check out similar monoblocks from Rockford Fosgate and JBL as well. If you don't mind buying elsewhere, almost any reputable manufacturer can provide a decent amp to power your Orion H2. Some online sites have pretty decent pricing, too.

Depending on your vehicle's electrical system, monoblock Class D amps may draw less current per watt output (due to higher efficiency). They usually cost a little less per watt as well (compared to competition quality amps). While purists/competition types will say that a Class A/B amp will sound better (due to higher damping/slew rate etc.), they also typically use some high quality, big ticket amps. A Class A/B will give you a bit less distortion, but will draw more current and throw more heat as well.

It really depends on your goals for your system, how many total watts RMS you intend to run for your system for sub and front stage (and whether your charging system can support that without an extra battery and additional modification).

You can probably expect the average car to be capable of running towards 1000 watts without ultra severe voltage drop (and the dimming lights that go with that), but you could probably go higher with the right Class D sub amp in the mix. With a HO alternator, upgraded battery, a second designated battery for your audio system, and "the big 3" upgraded, the sky is the limit (but will cost quite a bit). For an all-out system, Class A/B is a good choice, for a moderate street system a Class D offers more bang per buck.

Just pick something from a quality manufacturer rather than going super cheap. I would bet two Kenwood KAC 7202s would draw more current for 920 watts total output than a decent Class D monoblock in the 1000 watts RMS range- something to consider (especially if you'll be running a 2 or 4 channel amp for your other speakers on top of this).

Ray Zenz

oh nice, i have a camaro too, what year is yours?

...but my sound system is in my bronco

Ray Zenz

why are you having problems with it?