Subs not working well at all.

[1_johnboy]

I have just bought 2 12" Soundstream subs (Second hand) and a Earthquake T2000W/4 (ex demo) and also built my own sealed enclosure.

Problems are -

Subs were sold to me in good condition (unknown model) older subs, single voice coil 4ohm approx 300w rms. They have very large dust caps about 8" flat, they are coming off - not noticeable untill they are working. Cause a large viabration. Can they be glued back - not torn, just coming off?

The amp. Its a four channel bridged to 2 channels. When bridged it seems to power one channels more than the other ( just guessing this as one moves more than the other). If you switch subs to other channel it powers it fine. So guess there ok. Balance on head unit is even. Doesnt seem to be a balance on the amp it self.

The box, build by me to 2.4 cubic feet (700*320*400) in a sealed enclosure. I`m no builder, but did a ok job and screwd and glued the shit out of it. Maybe its jusat totally the wrong size/type.

Now to the part that I guess is due to the above factors.......bass seems crap, there almost isnt any. Its replace a single sony 12" and they sony was heaps better.

Could someone point me in the direction to correct this.

[Crisis63]

Dust caps should really not come off. Unless they have been exposed to extreme conditions like excessive sunlight or moisture. You can glue them back with PVA. I would be suspicious of them though.
Cabinet size is important to get the best from your drivers. Sealed less so but maybe Google the model and see if there are specs for the optimum box size. Also do you have acoustic wool in them? I would recommend using some if not.
Can’t really work out what is going on with your amp though. Check if the low pass filters are switched in. Also check the input sensitivity levels are equal.

[1_johnboy]

as odd as it sounds I cant actually find the model so sourcing the correct box size type has been hard. I just went with generic box size....cant for the life of me work out why they dont seem to be producing big bass.

That cobo should perform well....its just not.

Had a thought on the bridging not working correctly.....Maybe the rcs at the headunit might be unplugged or loose.

I dont have any Darcon/wool type material in the box

I`m pretty sure this is it, yet still unable to get a firm model

http://cgi.ebay.com/Rare-Old-School-...d=251572195207

[AmmoJammo]

how are you connecting an RCA signal to all four channels?
have you wired one of the subs out of phase accidentally? (connected the wires backwards)

[1_johnboy]

rca`s are wired to 2 channels only, and pretty sure they are wired up ok. Will double check

[AmmoJammo]

if you're only connecting the RCAs to two channels, then you're only using two channels.

which two channels are they connected to?

[1_johnboy]

they are connected to channels 1/2 and obviously the others are 3/4 (which have nothing connected to them).

[1_johnboy]

Do you guys think the box size is ok, or maybe it should be bigger or maybe even go a ported setup

[MAG00]

The amp. Its a four channel bridged to 2 channels. When bridged it seems to power one channels more than the other ( just guessing this as one moves more than the other). If you switch subs to other channel it powers it fine. So guess there ok. Balance on head unit is even. Doesnt seem to be a balance on the amp it self.\

they are connected to channels 1/2 and obviously the others are 3/4 (which have nothing connected to them).

That is most likely your issue, the sub bridged across channels 3 and 4 isn't working because there is nothing inputted into 3 and 4. You need another rca cable from the headunit to channels 3 and 4 or you need 2 splitters like this.
One splitter on the left rca, and the 2 male inputs on that splitter go into channels 1 and 2.
One splitter on the right rca, and the 2 male inputs on that splitter go into channels 3 and 4.

As for the lack of bass, check the amplifier's fuses. Also check that you haven't set the Low pass filter too low (for the sake of testing 150hz should be ok). Your gains and your crossovers are likely to be the culprit here.

[1_johnboy]

thanks for that, as soon as it was suggested it started ringing bells. Will check and correct, as for the box - Do you think the size is ok. Seems sound stream suggest either a sealed or vented enclosure will do. Recommended enclosure (sealed size) 1cuft per driver. I have made the box 2.4 for 2. Now this is obviously larger than recommended. Would this be a issue?

Also a great possibility is that my maths is incorrect, does my above box dimentions equate to 2.4cuft?

[Crisis63]

Vented enclosures need to be built very accurately to work at their best. This includes internal dimensions and even taking into account the volume taken by the speaker basket and magnet. And the port also has t be spot on. I would stay with a sealed enclosure if you are doing it yourself.
And get some acoustic wool to stuff in it.

[1_johnboy]

I want to build a box to suit them correctly....But am unable to find any correct information on them

[StoneX]

The box volume is fine. The slightly larger box will give you slightly more low bass.

[1_johnboy]

I didnt factor in the driver displacment when building it...so probably something like 2.1cuft

[HCVP]

Expecting to be able to run 2 subwoofers bridged across 2 full range channels on a 4 channel amp is your first problem. Without specs and model numbers of either the amp, or the subs, and without knowing what order you have wired the subs in (series, parralel, or something random) then i have no idea what impedance load you are presenting to the amp.

If you want help, go out to your car and write down the model number you see on the back of your amplifier. Do the same thing for the subwoofers. I will look at each components specs online, and providing the amplifier can be presented with a suitable load to drive both subwoofers, i will post you up a diagram of exactly how everything should be wired. Don't link us back to something you think it "may" be. Wiring voice coils in the wrong order is a fast tracked path to disaster.

The volume of the box has nothing to do with it, it's only fine tuning. It doesn't matter whether they are in an enclosure, suitable or not, or just sitting free air on the boot of your floor, if their not working, then their not working.

[1_johnboy]

Help would be appreciated, most of the information your asking for is in my original post. As stated I can't find a firm model number. Says soundstream rubicon 12. That's it. No actual model number.

[wraith]

Sounds to me like you don't the RCA's hooked up properly.

OP's amp:
T2000W/4

Sub's possibly
Soundstream Rubicon 12 inch

[1_johnboy]

Correct amp, but not that model sub. Mine is a single 4 ohm voice coil. I know as stupidas it sounds. But here is no model on the drive. But the eBay link I posted earlier is the same looking. So a older model that the link you provided mate. All that is written on the back is rubicon 12. But there are serveral rubicon 12 models over the years.

Splitting the rca did definatly help. Now just have to fix the dust caps to get the sound right. So thanks for the suggesting on that solved 50% of the dramas.

Just want to find out if changing box size/typle will help things out

[1_johnboy]

thanks for all the help guy, all the above suggestions have led to my subs now working well. Its been 5-6 years since I`ve had 2X12" subs. I think I might be getting old. Seem abit to much bass