Not really "big" big.. but like 280w RMS big.

I used to have it hooked up to an IMPP (Pioneer) something or other 12" 500w max. It did pretty well and hit hard enough to my liking on a conservative gain setting.

I got my hands on an el cheapo Jensen bazooka-tube-lookin' sub and have been running it instead ever since. Is it weird that I have to turn the amp gain up even higher to get the little sub to hit? I figured I would have had to turn the gain down lest I blow it up. I'm pretty sure I have it almost maxed out right now.

So basically, I'm using more amp power yet getting less sound from a lesser subwoofer. I know a 8" Jensen is not going to hit like a Pioneer 12", but I should be able to clip the hell out of it if I wanted to, right?

There is no model number or anything on the Jensen, but there are two sets of connections. I am assuming the 2nd set is just to connect to other speakers in parallel.

7/28/2009 11:22:34 AM

You...have something wrong.

What impedance was the sub and what is the tube?

Is the source the same?

7/28/2009 12:05:47 PM

the sub is 4ohm SVC (TSW-304C)

the tube has no documentation on the Internets as far as I can tell But I would assume such a POS to be 4ohm as well. SVC.

same source as in the same amplifier? Yes. same car, same configuration. USX 2080 rated at 280w RMS bridged 4ohm.


----------------------
Here's another question. Say I upgrade the woofer in the tube.. are mounting hole locations/distance for screws universal for same-diameter subs? I know the actual cutouts for the speaker can vary. Not trying to make an adapter bracket.

7/28/2009 12:28:48 PM

All other things being equal; there is no way an 8" sub is going to move anywhere close to as much air as a 12" sub unless that 12" sub was just severely underpowered (it sounds like it wasn't.) It's like asking why your V-6 isn't putting out as much power as the V-8 you used to have in the car.

In addition, Jenson is some junk. Not that Pioneer is that much better, but Jenson can only be considered an upgrade if you have Roadmaster or something.

So you have a low quality sub that is 33% smaller than the one you used to have. It's no surprise that the thing isn't hitting.

7/28/2009 1:29:05 PM

I'm not asking for my 8" sub to do 12" duty. I'm just wondering why a good gain setting for my 12" performs pitifully for my 8" sub.

I downgraded b/c the Jensen tube was free and saves a bunch of room/weight over the 12" setup.

7/28/2009 1:40:15 PM

Because you have to drive the 8" sub a lot harder than the 12" one for the same output volume.

7/28/2009 2:01:44 PM

another thing to consider is the design of the enclosures. a ported/bandpass enclosure will have more output than a sealed enclosure.

7/28/2009 3:17:38 PM

"Gain" is just a tool to match the signal coming out of your CD player efficiently to the amplifier signal going to the speaker. In theory, and when I set up systems, you adjust the gain without taking into consideration the speaker.

For instance, I have 2.5v pre-amp outputs on my Alpine head unit. I have to turn up the gain on my subwoofer/main speaker amp about half way due to the amp having to make up for the lack of signal coming from my head unit. Now the same amplifier setup hooked up to a Kenwood Excelon which has 4.5v pre-amp outputs would require the gains to be run much lower, since it's getting a better signal. You should be able to switch around subs without having to touch anything other than crossover and maybe (if you run it, I dont) the bass-boost.

The reason you are having to turn your gain up is because you have a crappy zooka tube. You are using a dirty signal to run the sub to get it as loud as the 12" with a clean signal.

Jensen is not all that bad, and Pioneer is certainly not crappy either. Now me, I'm an Elemental Designs type of guy, but some of the lower-end brands perform just fine provided you arent looking to rattle cars. In which case if you are, you should be drawn and quartered...

[Edited on July 29, 2009 at 12:57 AM. Reason : ...]

7/29/2009 12:48:13 AM

Oh, and as far as replacing the Bazooka sub with something else in the same tube....BAD idea. That sub (while crappy) is designed to work best with that tube. Likewise, the tube is designed to work with that sub. You put another sub in that same tube, you better be prepared for some CRAPPY sound.

Now, if you want some good sound on the cheap, try this...

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-854

That little sub should match up nicely with your conservative Jensen amp, and in the right box ( I prefer a ported box designed with Winsd) it should come close to the 12" you had in terms of down right output. Not the same output below about 40hz, but any type of rock/country/techno bass, it sound be just as loud, and probably sound cleaner to boot.

7/29/2009 12:52:14 AM

Quote :

"So basically, I'm using more amp power yet getting less sound from a lesser subwoofer."

gain setting does not limit power output of an amplifier. the amplifier will reach maximum output regardless of the gain setting.

Quote :

"Is it weird that I have to turn the amp gain up even higher to get the little sub to hit? I figured I would have had to turn the gain down lest I blow it up. I'm pretty sure I have it almost maxed out right now. "

is this in the same vehicle or same radio as your other setup with the 12"? just curious as to what's providing the signal to the amplifier? if it's the same setup as before i believe you are just expecting too much out of the tube. it's quite possible the speaker may have a resistor soldered on to dissipate the heat when it's overpowered to prevent damage so you might not be able to bottom it out.

7/29/2009 9:09:38 AM

^nope no resistors at all and yes, same HU. Just a simple passive sub.

Quote :

"Oh, and as far as replacing the Bazooka sub with something else in the same tube....BAD idea"

even if the tube (.6 cubic feet) is already the recommended ported volume for the new subwoofer? .6ft^3 seems to be a common spec among 8" subs. Not sure about the Tang you posted (not listed), but most of the ones on Crutchfield want that spec. It's the port lengths and diameters that I can't do anything about.

I can make a box no problem, but if I can't throw a new sub at this thing (i.e. not having to spend $25 more on a sheet of MDF) and have it sound good, I'll just leave the Jensen as is.

and back to the other question I had:
Say I upgrade the woofer in the tube.. are mounting hole locations/distance for screws universal for same-diameter subs? I know the actual cutouts for the speaker can vary, but I'm not sure about the mounting points.

[Edited on July 29, 2009 at 12:26 PM. Reason : ]

7/29/2009 12:17:57 PM

unless you are putting in an 8w7, you aren't going to benefit from replacing the sub in that tube.
If you aren't happy with the 8, and the 12 was too big, go to a 10 and smaller sized box.

7/29/2009 1:07:30 PM

Quote :

"There is no model number or anything on the Jensen, but there are two sets of connections. I am assuming the 2nd set is just to connect to other speakers in parallel."

I had a Jensen tube sub like this (maybe same one) that I got from JC Whitney back in the day. Are you sure the second set of connections isn't for the other voice coil (i.e. dual voice coil sub)?

7/29/2009 1:46:20 PM

bigger is always nigger

8/4/2009 11:36:26 AM