Simple question about rear deck speakers

bokdaddy

Right now I have the db690's in my rear deck and am not satisfied with how muddy the bass is and how poor the midrange and highs are. Most factory systems sound better than what I've got with those. I'd like to get a better match for my db525's and was wondering if replacing the 690's with the db650's would be smart. I know I'd have to do some work to get them to fit but does anybody think I'd get a noticeable difference by doing this?

neomagus00

are you powering the speakers with an HU? if so, it is very likely that you'd get better sound with stock speakers. aftermarket speakers essentially need amplification.

barring that, 6x9s will have more bass and be a bit less clear than 6.5s. but from your description, i'd say amplification is in order.

bokdaddy

Thanks for your reply. I've asked a few questions here before and everyone tries to tell me I need to get an amp. So far I've been stubborn (I just don't like the idea of doing all that work). But sooner or later I guess I'm going to have to give in. Thanks again.:)

neomagus00

it truly isn't a ton of work, all you need is patience and time (and apparently, beer helps, too, if you're of the appropriate age and disposition ).

exalted512

whats this appropiate age bs?
-Cody

swerve

Originally posted by exalted512
whats this appropiate age bs?
-Cody

it's called the law... get a clue buddy.

exalted512

its only wrong if you get caught
-Cody

Thom

If they're running off a head unit, is it OEM of aftermarket? Quite a few OEM systems have EQ built in to make the OEM speakers sound half decent, but putting in aftermarket speakers can sometimes sound worse.

AustinKP

Originally posted by Thom
If they're running off a head unit, is it OEM of aftermarket? Quite a few OEM systems have EQ built in to make the OEM speakers sound half decent, but putting in aftermarket speakers can sometimes sound worse.

That's a very good point that I hadn't thought of. If the factory HU is tuned for the peaks and dips in the response a certain speaker, putting in aftermarket speakers with a relatively flat response would sound awful.

MacLeod

Not to mention that a lot of OEM head units make about half the power of an aftermarket unit.

The reason we tout amps Bok is that if you dont properly power a speaker its not going to sound as good as it can. Think of trying to tow a 10,000 lbs boat with a 1.3 liter 4 cyl. engine. Sure itll move but....

Personally I think 6x9s sound just as good as round speakers assuming they are quality made and both the Momo and DB 6x9s are. I had a set of Momo 6x9s and absolutley loved them. There are times when I think I may want to take out my beloved MM6 mids and stick in the 6x9s again. They make more midbass and sound fuller to me.

I think you should stick with them just properly power them and if youre not using an aftermarket head unit you should consider it.

Also, installation could be a problem. A lot of rear decks are like sheets of tin foil. One option is to bolster the strength of the deck by cutting out some baffles from MDF and mouting the speakers to that. It may help.

And lastly, dont expect much bass out of anything except a subwoofer.

Joelsbass

if you go with an amp, get a decent 4ch so you have some power to your fronts too...

bokdaddy

Thanks for your input guys. Unfortunately I paid the price for not listening to the people who know best. My entry level Pioneer head unit seems to have blown the woofer on one of my db525's. I immediately took out the rest of my db's and put the factory speakers back in. I'm going to wait to put them back in until I can afford a head unit with at least four preouts, a decent four channel amp, and a new pair of db525's. I should have listened months ago...:(

MacLeod

That head unit shouldnt have hurt those DB's. It doesnt make enough power. You should check it and make sure everything is hooked up and if it still doesnt work, you should contact Polk customer service about getting a replacement.

bokdaddy

It was still connected, it was just making a flapping noise like paper in wind. I was thinking they maybe blew from being underpowered? No?

neomagus00

highly unlikely off of an hu... he's right, you should call polk, they might have you test it in some way and if necessary you could get a replacement.

audiobliss

Wait a minute....I thought you were much more likely to blow a speaker from underpowering it than from overpowering it. I thought that, with a good, clean, powerful amp, you could sorta push the envelope of the speaker's limits. But with a cheap amp (i.e. HU), it would quickly resort to distortion and clipping because of its lack of power and that that would cause the speakers to blow.

Have I just missed the whole picture here? IF (if) he turned up the HU really loud so as to make the HU's 'amp' distort, wouldn't that easily blow the speakers? ....if I remember right...that's why y'all told me not to turn up my components until I get an amp.....

-curious & confused

swerve

Originally posted by audiobliss
Wait a minute....I thought you were much more likely to blow a speaker from underpowering it than from overpowering it. I thought that, with a good, clean, powerful amp, you could sorta push the envelope of the speaker's limits. But with a cheap amp (i.e. HU), it would quickly resort to distortion and clipping because of its lack of power and that that would cause the speakers to blow.

Have I just missed the whole picture here? IF (if) he turned up the HU really loud so as to make the HU's 'amp' distort, wouldn't that easily blow the speakers? ....if I remember right...that's why y'all told me not to turn up my components until I get an amp.....

-curious & confused

that's what I've always thought as well.

audiobliss

Originally posted by swerve
that's what I've always thought as well.

oh no......we agree on something.....lol...

exalted512

Originally posted by audiobliss
oh no......we agree on something.....lol...

yup, that right there should tell you something's wrong. if properly set up, you will NEVER blow a speaker by underpowering it. The reason why many people say underpowering a speaker will more likely blow it is because when youre underpowering, its human nature to want to put a little more power to the speakers, thus, putting the gains a little higher than they should be...
the phrase "underpowering a speaker will blow it" is totally incorrect. If you set your amp will it wont distort, underpowering is perfectly fine.
But even if the amp in his head unit did distort...take this into account. any speaker can handle a clipped signal. The problem with clipping is that your nice little 400 w peak amp puts out 8-1200 watts when clipped, so your little 200 watt speaker dies...But lets say have a 50 w peak head unit that clips, it will never get close to 400 watts, thus if you have a 400 watt sub, you have nothing to worry about.
-Cody

audiobliss

Interesting food for thought, there; I'll have to chew on it a while. So you're saying that if you have a powerful amp (or at least one that puts out the speakers' max wattage or there-abouts) and it clips, it kills your speaker. But in this case the amp, even clipping, couldnt' put out enough watts to kill the speaker. I see, I see......

exalted512

yea, the problem with clipping is that its a square wave rather than a sinusoid wave. a square wave can multiply an amps power by as much as 4x its rated output (and thats for amps that put out their rated power, not underrated amps)
-Cody

MacLeod

The simple way to put it is take a 500 watt speaker and hook a 100 watt amp up to it. You can crank and clip the hell out of that amp til the cows come home and itll never put out enough power to hurt that 500 watt speaker.

A speaker doesnt know the difference between a distorted signal or a clean one.

The distortion that IS bad is the kind the speaker makes when its being powered beyond its limits. That means its about to give up the ghost. And this can happen with clean or distorted power.

People generally think underpowering is bad cause most would not power a 500 watt speaker with 100. Most would consider underpowering a 500 watt speaker to be about 300 watts. Now when this 300 watt amp is clipped itll likely send a 600+ watt signal thus ending the 500 watt speaker.

Clear as mud eh?!

This stuff makes my eyes cross too. Best way is to match your amps to the speakers capabilities.

neomagus00

agreed, matching is best.

just to reiterate, the confusion stems from the usage of the term 'underpowering'. feeding a 400W sub from a 300W is underpowering; the danger, as mentioned, comes when you ask that 300W amp to make more than that... this sends you into clipping... the 400W sub can handle up to 400W of dissipated power; as already said, it doesn't know if what it's playing is square or sinusoid. when you push your 300W amp further into clipping, past the 400W that the sub can handle (and you could probably make that amp do 1200W for a while!), the sub can't take the heat (literally) and melts. The other end of the scale is, of course, over-excursing the sub, which can mechanically destroy it as well.

Mjr7531

Well, the thing is you guys are forgetting about the tweeter in the speaker, if you over drive a 150 watt rated 3-way yes. The woofer can handle it, but the tweeter isn't rated for it, maybe only 15-20 watts. and when you get a good square wave going, it send all the energy to the tweeter and pop, there it goes. Food for thought.

MacLeod

Most quality tweeters, at least in car audio can handle a good bit of power and most can take as much as their midrange counterparts. For example, my Polk MM6 tweeters are getting over 70 watts each and they soak it up just fine.

MB Quart tweeters can take obscene amounts of power, well over 100 watts each without so much as a whimper.

Youre right tho that the tweeter is usually the weakest link in a component system, but the principal still applies. As long as the clipped/distorted signal is below the limits of the tweeters power handling, the tweeter will be fine.

LittleCar_w/12s

Originally posted by Mjr7531
Well, the thing is you guys are forgetting about the tweeter in the speaker, if you over drive a 150 watt rated 3-way yes. The woofer can handle it, but the tweeter isn't rated for it, maybe only 15-20 watts. and when you get a good square wave going, it send all the energy to the tweeter and pop, there it goes. Food for thought.

Actually, given the nature of the passive crossover used to filter out a tweeter's input, it will most likely not even see any power at all. The tweeter will receive a tick of power at the beginning and end of a square or clipped signal, and via the nature of the clipping of a waveform, the higher frequencies that overlay the lowerr ones are completely clipped off (because they lie on part of the sine wave overextending the voltage cap of the amplifier in the output stage.)

So, no, you cannot blow a tweeter with a clipped full-range input as seen on a two or three-way. If the tweeter is fed through an active crossover placed before the clipping ever occurs, and then the high-pass filtered signal is THEN clipped, you will eat the tweeter.

On the other hand, the capacitor used to crossover a 2/3-way can only absorb so much energy, and I have seen them explode. At that particular time, you run a 99.9% chance that the packing is shot out of the capacitor allowing the tweeter full range input. You will almost always eat the tweeter if you can manage this feat.

SO there.. :eek:

neomagus00

2 points to add -
1) i think that because of the harmonics you get in a square wave, the tweet gets a taste of it, but not enough to hurt it.
2) the power distribution of music is rather low in the treble end - it doesn't take much power to give you a strong cymbal crash. but, as mac has noted, tweets can take a LOT of power. thus:

wouldn't your ears bleed from the distortion before a true squarewave becomes even a remote possibility? i think that anyone that drives their system into a profile even coming close to a square wave deserves what happens to their speakers... that's just not right...