Anyone have 4x6 plate speakers? Do i need crossovers?

[jbuening]

Here's the deal. I bought a pair of Polk MOMO MMC460 speakers and they are popping and cracking with any slight amount of bass and volume. I had the EQ set at 0 for low, mid, and high frequency and the volume was at "Comfortable Elderly" listening level and it still popped. I turned the low to -6 and it stopped. It seems to be coming from the 4" woofer.

I've installed pioneer 4" round speakers and they've never done that. I am running these 4x6's straight to the Pioneer head unit. I posted this on a car audio forum but didn't get much response. The tweeters appear to have capacitors installed already to filter out the bass. Polk audio suggested installing bass blockers, but whats the point of having a 4" woofer and not get anything out of it? I know the 4" woofers produce very little bass, but with bass blockers on it i am mainly just getting sound from the tweeter. A tweeter would have been much cheaper than this pair of speakers, which are supposed to be top-of-the-line ones. Polk Audio offered to repair them if they are indeed blown, but i don't want to blow $20 more on shipping if they are not in fact blown and just require bass blockers. Anyone else running 4x6 component speakers without bass blockers? I'm not a car audio guru, which is why i'm seeking more advice before i send them back to the factory. Thanks!!!

Oh and one thing i haven't done is try running new speaker wire from the speaker to the head unit. I am using the stock 1970 speaker harness but i wouldn't think that would be the problem. Anyways, thanks for the help/tips!!!!

 

[mudbilly]

are they mounted right? do they still pop if they are not mounted in the car?

never heard of base blocker

 

[jbuening]

I'll pull the speakers from the door and see if they still do the same.

Bass Blockers: http://www.crutchfield.com/S-Em8tlQ1Wxd5/cgi-bin/prodview.asp?i=127BB150A2

 

[jbuening]

Quote from the Polk website "2nd Order x2 (high and low) Crossover with Mylar Capacitor/Air-Core Inductor components for better dynamic impact and transparency."

Doesn't this mean that both speakers have a cross over installed?

Also quoted "Stiff Polypropylene Cone with Carbon Fiber Dustcap for tight, punchy bass and clean mids." Punchy bass does not include blocking the bass, am i correct here? Just making sure the speakers should be repaired and not just patching the system with bass blockers.

 

[mudbilly]

i find it hard to believe that a new set of Polk speakers don't sound great right out of the box..........

is the impedance correct?????

do you have a home unit that you can hook the speakers to???

 

[jbuening]

Impedance as in ohms? You bring up a good point!! Could the old harness/stereos be a different impedence? I'll also try to hook up my digital multimeter to see what kind of ohms the speakers are running at. Yeah i was pretty disappointed to say the leak. I'd heard nothing but good things about Polk audio.

 

[ForceFed70]

Speakers crackling/popping with only a small amount of bass are blown speakers.....sorry. I'm 95% certain a brand new set of speakers wouldn't do that.

"bass blockers" lol... what ever happened to calling them a filtering capacitor...guess it sells better to the dumbass teenagers.

 

[180 Out]

I like Mudbilly's idea, to hook them up to a home stereo. Just pull the speaker wire from the back of your home speakers and connect it to the Polks. If they check good then the prob's in the car install.

I would definitely not use the OE speaker harness. You don't need to use Monster Cable or anything (although that's what I do always use, but I would use at least a generic 12 gauge speaker wire.

For that matter, I would never run a speaker off the head unit. You might as well keep the Pioneers.

Amps don't have an impedence rating per se. The lower the impedence, however, the more current you need from your amp to keep from getting clipping. Clipping is when the amp doesn't have enough power to reproduce the sine wave form that the music source is putting out; it chops off the tops and the bottoms. Picture the difference between trying to blow into a straw and trying to blow into a 2" pipe. That out of breath feeling you get with the pipe is the same thing your amp is feeling when it's trying to drive into a sub-4 ohm load. (4 ohms is the std in car stereo.)

Anyway, I'll bet anything the Polks are fine, that you've got a prob with your wiring, you just didn't know it until you stepped up to a speaker with some accurate reproduction abilities. New speaker wire should fix it, but a separate amp will make the Polks come alive.

A "bass blocker" sounds like what used to be called a high pass filter, i.e., an electronic device that only lets frequencies higher than "X" Hz pass through it. A cross-over is more complicated; it serves the function of a high pass and a low pass, but it has to have a blend in the middle. How it does all this is a question for an electrical engineer, which I am not (liberal arts major here). I would say no, you don't NEED one, but your system would sound better with one.

 

[Jimmys66]

A "bass blocker" sounds like what used to be called a high pass filter, i.e., an electronic device that only lets frequencies higher than "X" Hz pass through it. A cross-over is more complicated; it serves the function of a high pass and a low pass, but it has to have a blend in the middle. How it does all this is a question for an electrical engineer, which I am not (liberal arts major here). I would say no, you don't NEED one, but your system would sound better with one.[/QUOTE]



This is exactly what a bass blocker is and you can probably get them at a local stereo shop and skip the shipping. There are different size blockers for different speakers sizes. They don't block all bass. If you buy the right size(freq.), they will only block the bass that your speaker wasn't designed to produce and it will use the power more efficiently to the range it was intended. A 4" woofer should not be expected to produce tones that a subwoofer would. With blocker you can also run them louder before they will distort.

Think of them like a rev limiter, you can run a motor to 10,000 rpm but it's going to sound like hell and it's not going to last long.

Here is another thing, some high end speakers have an operating range, if you will. They need a certain amount of juice to work right. If the head unit doesn't have enough wattage for a certain speaker it will sometimes produce the noise that you are describing.

 

[jbuening]

This is exactly what a bass blocker is and you can probably get them at a local stereo shop and skip the shipping. There are different size blockers for different speakers sizes. They don't block all bass. If you buy the right size(freq.), they will only block the bass that your speaker wasn't designed to produce and it will use the power more efficiently to the range it was intended. A 4" woofer should not be expected to produce tones that a subwoofer would. With blocker you can also run them louder before they will distort.

Think of them like a rev limiter, you can run a motor to 10,000 rpm but it's going to sound like hell and it's not going to last long.

Here is another thing, some high end speakers have an operating range, if you will. They need a certain amount of juice to work right. If the head unit doesn't have enough wattage for a certain speaker it will sometimes produce the noise that you are describing.

Yeah i kind of went on a tangent with the bass blockers and crossovers. I know the difference between the two. The caraudio forum people suggested using crossovers but said that bass blockers should not be needed. Kind of forgot to add that.

From the Polk Audio website, the recommended RMS of the speakers are 50W. My head unit "claims" that it is a 50Wx4, but whether or not it actually produces 50W rms is another story. I would like to get an amp in the future, but funds currently aren't available for an amp. I got these speakers new in the box for roughly $30 for the pair. If it wasn't for such a great deal, i would have went with a cheapo pair. We're talking a classic mustang that has loud exhaust and poorly placed speakers, so i'm not looking to have a topnotched stereo system. I just didn't want the popping sounds from speakers that sounded like they were blown.

I guess i didn't think about the bass blockers only blocking the extremely low frequencies that subwoofers are expected to take. According to the Crutchfield website, the recommended bass blockers for low power systems is 600Hz and high powered 800Hz for 4"x6". The customer representative for Polk Audio first recommended 600Hz, but in the next email recommended 300Hz. I may just bring these by the local Car Audio shop and have them test the speaker without and with bass blockers to see if it helps. I guess now i don't mind installing the bass blockers as long as the speakers themselves are not blown (now that i know bass blockers don't block all the bass). Thanks everyone for all of the help. I'm still trying to learn about Car Audio and it is slowly starting to sink in

 

[iskwezm]

Bass Blocker is a brand and its been around for over 10 years.

There is nothing wrong with the speakers as I have used/sold Pioneer,Infinity,MB Quart etc. They will all do the same due to the amount of excursion on that itty bitty so called woofer. I usually cross them over at about 400-600 Hz, but i run them through a amp with a built in variable crossover. The factory wiring will have nothing to do with the ohms the speaker is at

 

[jbuening]

The Polk Audio website says the speakers have built in crossovers. Wouldn't you think they would have them crossed over properly to begin with?

 

[Jimmys66]

The crossover is probably just to the tweeter. Look at the where the wires connect to the speaker. If the wire goes directly from the tab to the woofer there is no crossover. If there is a little diode on that wire, then it does.