Neofate

iTrader: (1)

Hey guys,

This has been brought up in numerous ways throughout the searches I read,.. but I'd like fresh responses directly to the question/point.

Basically this is what I have:

1994, LS 400 -- With Pioneer system.

Only change so far,.. Pioneer factory headunit has been removed and I put in an Alpine 9886 CD player/mp3/aac/ipod/usb -- I also added a Rockford power driver to the sub from the back of the headunit. (Added a little more punch to the sub).

With this setup I have the sub *completely* separated from the other speakers. It can be turned off, turned up and down, and has cross-over controls for the sub alone via the Headunit. I was quite proud I was able to do this.

The sub is factory as are all the speakers, and is running off a factory *pioneer* amplifier.

If I have been told correctly the pioneer amplifier runs at 40watts RMS. (Is this correct?)

Here is my next step. I would like to replace the factory 8inch sub with an IB/Free-air subwoofer that would fit without *any* modifications whatsoever. Direct bolt-on.

I would also like to use the factory amplifier.

Given this,.. Could you guys recommend your choice of sub for my application, given the specs and layout I have. It is Pioneer, how it is controlled and so forth?

The reason I want to change is not because the factory doesn't provide enough bass, but because the factory sub is being pushed too hard. It sounds great, but I have to back the output down on the headunit if a particular song comes up in my playlist. (More bass, back it down due to it sounding a little 'thuddy' if that makes sense. Like if I really cranked it up, in time the sub would be damaged). I need something that can handle the power and have room to spare.

Evidently this would give me a touch more bass, and would make it cleaner.

The sound I am talking about the factory sub is now producing if I give it enough output is sort of like the cone is hitting a cardboard box. Doesn't sound awful cranked up, but I can just tell it is too much for that speaker. Odd coming from the factory amp right? But with the Power driver and aftermarket sound processing I can see why.

Don't get me wrong, with the outputs set right on the headunit everything sounds great -- I would just like, again, the sub to be able to adequately handle the power of the factory amp and power driver currently driving it. Given this, it wouldn't take much of a sub to grant this need/want of mine.

Not having to buy an amp, and the power rating being so low -- I would think I could get away with an inexpensive replacement.

I would think under $100.00 from an online dealer.

So links would be fantastic, though names are fine as well.

Thank you so much..

(Ultimately I will be , over the next year, be replacing all speakers.. but for the forseeable future just the sub will be replaced. -- I am not looking for bass that can be heard outside the vehicle, just a clean sound inside).

Robert_J

Are you pushing your sub to its limits or are you pushing your amp too hard and clipping it? Have you checked the output voltage to see just how much power it puts out?

-Robert

Neofate

iTrader: (1)

Good question. No I haven't checked the output of the amplifier since having the power driver in place. I suppose I should, -- Though I assume judging on the noise I hear it is the sub, not the amp. The sound is like the cone/driver is physically being pushed too hard. A muted thud sound. Almost like it is hitting something, but it isn't. I dont' crank it up, as I don't have the need to, nor am I trying to bust the speakers/sub. I can just tell something in that area needs replacing.. Unless you think the factory sub can handle alot more than I am giving it credit for.

Robert_J

Pushing a sub to its limits isn't a thud. It's more of a clack. Metal on metal when the voice coil crashes into the back plate or the triple joint hits pole piece. Testing voltage with a DMM will verify power. If you have an o-scope you can determine clipping.

-Robert

19psi

sounds to me like you actually have 2 problems. your sub is being underdriven; you want more clean tight output than the sub can produce with the 40w it has to workwith. secondly, the sub is old and worn, uv rays and heat from the sun really kill speakers over time, it's just not as tight as it was when new.

Neofate

iTrader: (1)

Hrmm.. I have no 'O' scope, nor even know what it is. Oscillation? lol.

I do have meters though,.. and I will measure the input from amp to the sub, and out from amp today. As that is easily accessible. I will watch it as it 'changes' if it does during song changes. I will see if I am going high or low.

I imagine measuring off the smeaker contact terminals will give me the power reading I am after.

Yes the sub is old,.. But worn from use, not really. Worn from Sun and time .. As much as a garage kept car can be. The previous owner rarely used the speaker system.. and in the last 4 years or so of ownership I think never turned it on.

It actually sounds tight,.. as in the reaction time. Play a fast song the 8inch reacts to each beat without delay. Unlike a 12'' or larger subwoofer can do with really quick bass notes that become run-on beats with the slow reaction time of the subwoofer.

IE: Get a 15" sub, of lower/mid quality -- Play some Chevelle/Sevendust -- Now play that same music on an 8'inch or 10. Pretty drastic difference in the 'punch'.

If the amp is 'clipping' as Robert suggests,.. Then another aftermarket sub isn't going to do alot for this. If the sub is just being pushed a little hard,.. then an aftermarket would.

Judging by the sound it just seems like the sub needs to be upgraded.

The sound I am trying to mimic is as if the Driver is being pushed OUTWARDS beyond its designed limitations. IE: The sub would tear in its material if really cranked. Though it isn't metal on metal I am hearing.. so this sound is the amplifier?

I need to record this somehow.. but don't have any device to do so digitally and accurately.

Robert_J

Dan Wiggins of Adire Audio disproved this years ago with his Woofer Speed paper. It's also included in Audiopulse's Subwoofer Myths pages.

Punch is usually a bump in the sub's frequency response in the 50hz area. Usually caused by butting a driver in too small an enclosures. You get a Qtc above 1.0. See the response graph here.

If a driver is reaching it's suspension limits on the outward stroke, then it will more than likely be reaching the suspension limits on the inward stroke and more probably bottoming like I mentioned. Drivers all have different parameters. Xsus is the limit of the suspension. Xmech is the mechanical limits. Sometimes Xsus = Xmech. That is usually the case in shallow subs. But clipping a signal can sound like you are describing. The amp wants to push the sub the full distance on both the inward and outward stroke but the signal is not a perfect wave. It's like someone took a hedge clipper and clipped the tops and bottoms of the wave off. The amp is straining and the sub is accurately reproducing that strained sound.

-Robert