Turning off bass filter on head unit...bad?

[01rangerxl]

I have a 200 watt (50 watts per channel) Alpine head unit and 230 watt (75 watts RMS) Alpine Type-S speakers in my truck. Until today I wasn't aware that you could adjust the bass filter on the head unit. It was set to 100%, and now it is off completely. The bass from the speakers is excellent now as long as I keep the volume below "20" (I think 30 is the max, I have never turned it all the way up); above that it begins to distort. I mean it practically sounds like it has a small sub it hits so hard now. Am I going to damage my speakers like this though? I figured since on paper the speakers can handle more than the head unit's output I should be fine, but I'm not sure. The bass filter was probably there for a reason...but the speakers sound awesome with it off, so I want to leave it that way. Any input?

 

[aquariuscsm]

I`m guessing it`s the same thing as the subsonic filter on my home reciever. If so,I`d keep it on. Mine`s designed to keep the amp from "clipping" and sending distorted power to the speakers. Distortion aka "amp clipping" is what usually fries speakers` voice coils.

 

[tomcat27]

Yes, you could damage your speakers, depending on what brand they are! you are driving the amp into extreme distortion. First, the Alpine head units are really closer to 18W per channel. (forget the 50W claim, trust me) if you want a quick upgrade, alpine has a plug and play "power pack" upgrade the KTP-445 that will plug into any Alpine head unit 2005 or newer. its boasts a true 45 watts per channel and makes a large difference. costs around $140.

the main reason to use the "bass filter" is in the event that you are running a powered subwoofer - in that event you will want to filter the lows out so your main amp and speakers dont take the low freqs.

if you really want to open things up, add a real Alpine external amp like one of the V-Power units or one of the new digital amps.

alpine makes some incredible stuff. if you have more questions, so dont hesitate to ask. one of my friends is a Mfr Rep for Alpine... and I wouldn't run anything less (even before i knew him)

 

[badtlc]

as long as your speakers aren't distorting, you will be fine.

 

[aquariuscsm]

Originally Posted By: tomcat27
First, the Alpine head units are really closer to 18W per channel.


You got that one right on! Most car stereo equipment is not "true power" like a home stereo amplifier. For example,a true 25 watt per channel car amp will blow away one of those over rated/power claimed 300 watt per channel things.

 

[IndyIan]

Originally Posted By: aquariuscsm
Distortion aka "amp clipping" is what usually fries speakers` voice coils.

Your head unit doesn't have the power to wreck your speakers with clean output but if you are clipping on the bass then that can kill them. I have to say I'm impressed with the newer decks and speakers. I've got some half decent pioneer 6x9's in the rear deck of my Neon and I was very surprised how much bass they produce. I used to run a small separate amp and box for bass but now I don't even bother. Real low stuff like 20-30Hz doesn't happen but it didn't with a small box either.

 

[VK56VD]

Your speakers will be fine. Don't push them to distortion as others have stated and they will last a good while.

 

[01rangerxl]

Well I turned the bass filter to "60%," but that wasn't good enough. They're blown...a casualty of the Geto Boys. I replaced them with a set of Pioneers tonight. So to answer my own question, yes, turning off the bass filter is bad.

 

[brianl703]

Did you happen to smell them burning before they blew?

 

[01rangerxl]

No, there wasn't any burning smell. They just started cracking and popping while playing "The World is a Ghetto" by the Geto Boys and I knew it was over. They still played okay at low volumes and low bass.

 

[brianl703]

Usually, if you're feeding enough power into a speaker to damage it, your first clue is the burning smell as the voice coil heats up.

Keep that up and the voice coil burns out, rendering the speaker silent. It actually takes a lot to burn out the voice coil on a larger speaker like a 6x8; the speaker will have been smoking pretty good for at least 30-40 seconds prior.

I'm not sure what happened with your speakers, maybe they've deteriorated due to age and the increased bass finished them off.

 

[01rangerxl]

They were not old at all. I do drive with the windows down a lot, so I may have never noticed the smell. The speakers did still play fine at lower volumes and bass levels, but anything over "15" on the volume led to major cracking and popping noises.

 

[rpn453]

I'd leave the high-pass filter off because I prefer full-range sound over volume. The speakers should have no problem handling the bass at reasonably loud volume unless you're boosting the bass. If you're doing that, it's time for a sub and some real bass!

Originally Posted By: aquariuscsm
Originally Posted By: tomcat27
First, the Alpine head units are really closer to 18W per channel.


You got that one right on! Most car stereo equipment is not "true power" like a home stereo amplifier. For example,a true 25 watt per channel car amp will blow away one of those over rated/power claimed 300 watt per channel things.


I'd take it even further, and say that the true clean power output is about 25W total, or 6W per channel with all four channels driven. The "18Wx4" CEA-2006 rating that Alpine gives for their "50Wx4" amps is still at high distortion levels (1% THD). Ratings for decent amplifiers are provided at 0.1% THD or less.

 

[brianl703]

There's only so much power you can get out of a head unit, due to the fact that the amplifier is running off of ~14V.

Bigger amplifiers use switchmode powersupplies to step up the 14V to something higher, upwards of 30V.

There's no reason they couldn't implement some sort of switchmode power supply into a head unit for more power...except for the lack of room and the lack of ventilation for good heat dissipation.

 

[rpn453]

Originally Posted By: brianl703
There's only so much power you can get out of a head unit, due to the fact that the amplifier is running off of ~14V.

Bigger amplifiers use switchmode powersupplies to step up the 14V to something higher, upwards of 30V.

There's no reason they couldn't implement some sort of switchmode power supply into a head unit for more power...except for the lack of room and the lack of ventilation for good heat dissipation.


As it is, I think the head unit is enough for most people anyway. Aside from the sub, I haven't bothered with an external amp to power my speakers in over ten years. I even have a couple of very old but nice little Rockford amps sitting around that aren't worth the effort for me to hook up. With the EQ flat, I get no distortion even at volume levels that I can't tolerate for an extended period. Coloration is the main problem with most car stereos, including mine.

 

[badtlc]

Originally Posted By: brianl703
There's only so much power you can get out of a head unit, due to the fact that the amplifier is running off of ~14V.

Bigger amplifiers use switchmode powersupplies to step up the 14V to something higher, upwards of 30V.

There's no reason they couldn't implement some sort of switchmode power supply into a head unit for more power...except for the lack of room and the lack of ventilation for good heat dissipation.


I don't know how familiar you are with electrical power, but 14V by itself is not a limitation of power or ability to produce power. You can theoretically produce as much power as you want from a 14V source. Those bigger amplifiers are still getting all their power from a 14V source.

 

[brianl703]

I said,

Quote:
Bigger amplifiers use switchmode powersupplies to step up the 14V to something higher, upwards of 30V.


That's because the amplifier circuit isn't running off of 14V, it's been stepped up to increase the power output. There is a power supply section inside the amplifier which does that.

You could also use lower-impedance speakers to get more power without using a step-up power supply. But, with a 14V supply voltage (and no switchmode power supply to step it up) and 4 ohm speakers, there's a limit as to how much power you'll be able to put into those speakers. Double the supply voltage to 28V and you will quadruple the power into that 4 ohm speaker (if the amplifier circuitry is designed to handle the increased voltage and power).

The 14V supply is a limitation as far as head units go because of the limited space and cooling available, which pretty much makes putting a step-up power supply inside the head unit a non-option.

But again, I find that I'm repeating myself. Perhaps the problem is mine. Do I not write clearly?

 

[badtlc]

Originally Posted By: brianl703
I said,

Quote:
Bigger amplifiers use switchmode powersupplies to step up the 14V to something higher, upwards of 30V.


That's because the amplifier circuit isn't running off of 14V, it's been stepped up to increase the power output. There is a power supply section inside the amplifier which does that.

You could also use lower-impedance speakers to get more power without using a step-up power supply. But, with a 14V supply voltage (and no switchmode power supply to step it up) and 4 ohm speakers, there's a limit as to how much power you'll be able to put into those speakers. Double the supply voltage to 28V and you will quadruple the power into that 4 ohm speaker (if the amplifier circuitry is designed to handle the increased voltage and power).

The 14V supply is a limitation as far as head units go because of the limited space and cooling available, which pretty much makes putting a step-up power supply inside the head unit a non-option.

But again, I find that I'm repeating myself. Perhaps the problem is mine. Do I not write clearly?


Saying the head unit has limitations is correct. Saying that it is because of 14V supply voltage is incorrect.

 

[brianl703]

The head unit has it's limitations because of multiple factors, including the 14V supply voltage. Because of that low supply voltage, an amplifier for higher power requires a step up power supply (added complexity) that wouldn't be needed if the supply voltage were higher. Therefore it is a factor.


Do you know why car speakers are 4 ohms instead of 8?

Hint: Supply voltage has a bit to do with it.

 

[aquariuscsm]

Originally Posted By: brianl703
Did you happen to smell them burning before they blew?



I fried the voice coils in my Electro Voice horns years back and it made the whole house smell like burnt rubber! I blew them with only 50 watts of dirty power (I ended up replacing the diaphragms). I now have close to 300 (clean power) and they`ve been going strong for 20+ years :^)