[MOB]

Fitted a pair of SWS-8 subs to my E92, yesterday - plugged them into my THA555 amp and they sound crap.

I did seal the enclosures well, with silicon sealant. Including the cable holes. Also dynamatted the bottom of the enclosure and the port.

Need to check;

- on the sub, one post is thinner than the other - which one is negative/positive? I have assumed thicker is positive - does it matter?

- connecting to the amp - the blaupunkt plug has + - + - ; I have connected one sub to one + - and the other to the other + -

- What sub settings on the amp need changing - I have left the input to 8v, tried low pass on and off. Left low pass at 50hz

- if I plug in the sub control box, it does absolutely nothing!!

The subs are moving very slightly, if I crank it up there is precious little bass.

Any help would be appreciated!!

[tpipta]

Switching the positive and negative will not affect whether subs work or not, it will however affect the phase in which the sub moves in and out. I would check the amp setting in the manual to make sure you have it in a stereo configuration. I googled the part number and it looks like it is a 5/4/3 channel amp. Do you best to try to maximize the output of the amp by getting into a stereo mode if possible.

Best,

Tony

Originally Posted by MOB

Fitted a pair of SWS-8 subs to my E92, yesterday - plugged them into my THA555 amp and they sound crap.

I did seal the enclosures well, with silicon sealant. Including the cable holes. Also dynamatted the bottom of the enclosure and the port.

Need to check;

- on the sub, one post is thinner than the other - which one is negative/positive? I have assumed thicker is positive - does it matter?

- connecting to the amp - the blaupunkt plug has + - + - ; I have connected one sub to one + - and the other to the other + -

- What sub settings on the amp need changing - I have left the input to 8v, tried low pass on and off. Left low pass at 50hz

- if I plug in the sub control box, it does absolutely nothing!!

The subs are moving very slightly, if I crank it up there is precious little bass.

Any help would be appreciated!!

[medrep]

Its been a while since my car audio days, and I dont know the amp, but I think you'll be lucky to find an amp powerful enough to power x2 8" subs? Particularly one that is not connected straight to the headunit via a sub preout?

Normally you would need x2 amps, each amp set to bridged to power each sub (or even a sub specific amplifier). For one sub and one amp = the + from the amp sent to + on the sub terminal, and the - from the amp sent to - on the sub speaker terminal. (The amp may have an illustration next to the terminals on the amp to specify which ones are used for bridging only)(and when i say bridged, bridged to output to ONE speaker/sub only, not bridged to power x2 speakers. Amp is usually set with the low pass filter on so just the LFE signals are sent to the sub. Also check there is no master setting on the head unit?

Are you currently using the original head unit? As mainstream after market head units will have specific sub pre outs to send the signal straight to the amp?

I wouldnt want to confuse you anymore, but make sure the amp is capable of powering a sub, and that it can be bridged if necessary to power x1 speaker/sub. Powering x2 subs from one amp is a tall order, that would have to be one meaty amp!

How powerful is the amp, and what is recommended power rating for the sub?

If the sub is, say 300watt rated, you'll ideally need at least a 1x200 watt signal into it. If you are sending a low power signal to the sub, you could damage the amp/sub quite easily, be careful. You can never have enough power!!

I would try to run one sub from the amp for now, connected as above. See how that goes, but check the amps capability first?

I preferred the thump of the 8" subs, compared to the typical R&B boom of the 10" and 12"'s. The 8" subs will not go as low as the larger ones, so the low pass filter settings will probably benefit from not going so low either, itll get flabby and distort.

I would have normally run a 1x400 watt into a 300watt sub, and taken care not too give it too much well or set too high. It was a common cause of system damage using underpowered amps into subs.

Good luck.

[BigBanana]

GiZZe's your man.

hopefully, he'll be along shortly.
That amps more than enough...

[CrimsonRedE93]

Doesn't sound good MOB, I will try and make the right sort of noises until Gizze somes along

I presume you ran new cables from each sub back the the amp seperately, normally I would have said that you have one of them out of phase so that they are cancelling each other out, but as you say the subs don't move that much I am not so sure.

Amp settings for maximum bass to check if it is working properly should be:

Low pass switch ON

Low pass frequency set to 250Hz, fully clockwise (gives 0-250Hz to the subs)

With the sub level set to 8V it gives you the minimum gain but you shouldn't need to take that down too far as the head unit output is around that level.

I presume that you have the base turned up on the head unit?

Did you get the 2 or 4 ohm subs?

[medrep]

Just googled the amp myself, yep thats more than enough power

Obviously a wiring issue then. I'll shut up and leave it to someone who knows the amp?

Looks a nice system, its got me interested now as well?

Could I ask how much the amp and subs cost you?

[MOB]

Originally Posted by medrep

Could I ask how much the amp and subs cost you?

Approx £500 for 2 subs, the amp and the BMW to Blaupunkt harness.

Everyone else seems to have had great results!!!

[MOB]

Originally Posted by CrimsonRedE93

Doesn't sound good MOB, I will try and make the right sort of noises until Gizze somes along

I presume you ran new cables from each sub back the the amp seperately, normally I would have said that you have one of them out of phase so that they are cancelling each other out, but as you say the subs don't move that much I am not so sure.

Amp settings for maximum bass to check if it is working properly should be:

Low pass switch ON

Low pass frequency set to 250Hz, fully clockwise (gives 0-250Hz to the subs)

With the sub level set to 8V it gives you the minimum gain but you shouldn't need to take that down too far as the head unit output is around that level.

I presume that you have the base turned up on the head unit?

Did you get the 2 or 4 ohm subs?

Each sub has its own speaker cable

They are the 4 ohm subs

Bass on HU tried on MAX

Low pass was off and freq set at 50hz - woohoo I thought, so I set at 250hz and put low pass on - no difference!!

I'm a bit confused about the speaker cable wiring - The amp plug has one plug, with 4 holes for cables +-+-

I've just assumed each speaker takes a +- but I've now seen references to parallel wiring..........all over my head a bit really!!

Thanks for everyones help so far, I'm sure its just going to be down to my stupidity!!

[quattrogmbh]

Using the amp in Monoblock mode, I think you might have to put the outputs into series to get the full power of the amp going to each sub. But I'll leave it to the experts to confirm.

[MOB]

Do I need to change any settings going from 4 channel to 5 channel? ie its a 5/4/3 channel amp that I've been using 4 channels of for a while - now added the 5th - cant see any switches etc?

[CrimsonRedE93]

The manual for the 555 states that if you are using the high level PNP input cables (special harness for E9X) you can only use the sub in stereo mode and not bridged mono.

The 5th sub channel is on normally, infact I don'y think you can turn it off.

One thing I am not sure is where it gets the sub audio from the front or rear input channels?, I guess you have tried adjusting the fader on the head unit and haven't got the rear faded out

[MOB]

oooh might be on to something there - I do have it faded more to the front - will try that tomorrow as it's hurricaning here tonight - cheers

[CrimsonRedE93]

Cool, Just remembered that most people had the rear faded nearly all the way out.

May be nothing to do with it

[trixman]

I have mine set, maybe incorrectly at a lot more than 8v. Obviously fronts and rears are at that but sub channel is much higher.

Was there not a seperate bass control unit you had with them? I got one with the 5 channel Blaupunkt.

I definately think its the settings. Only problem with mine at the moment is the lack of mid-bass, I have no real clear definition but its just a matter of playing with the levels, takes a while to get the sound right whilst on the move (as compared to sitting in the back with no ambient noise)

[trixman]

From Gizzes help with mine...

You need to set the front and rear levels to 8v, and do that NOW!
Turn is as far as it will go anticlockwise.


You also want to set the pass on the front channels up properly, unplug the sub speakers from the amp, now play something with bass, set it to 200hz or whatever it goes up to (clockwise) and slowly move it back towards 20hz. Keep going until you do not hear it going any deeper, will be about 100hz (approx).
Fine tune till you are sure it is as deep as it will go, you want as much bass from the fronts as possible, but you also want to stop bass you can't hear from reaching the drivers so you can push them with no distortion.

Now you want to set the subs up so they match what you have on teh fronts, so if you got down to 100hz on the front speakers set the subs to do everything below 100hz.

Now when this is done you fine tune the sub gains, the drivers are not as sensitive so you will have this above 8v, probably around 6v, it may take a few days of tweaking to get it so you can hear them but don't know they are there. If that makes sense?

Then use your bass and treble to fine tune.

With the rear channels I actually use the low pass filter, so I cut out the treble so it gives some rear fill but doesn't drag the soundstage into the rear, vocals stay up on the dash. So I set it to cut out everything above 5000hz I think it is, and then use the high pass so no bass below 100hz gets through either, so they are only there to add some fill in the rear.

[MOB]

Right a bit pf progress...........

Fader was ok

Sub input/gain was at 8v as I thought I couldn't shift that, but looking above that isn't the case - so put it to about 5v and I now have bass, but horrible wooly bass, no real punch.

I think all my settings need looking at as above so thats my lunch hour sorted!!

[trixman]

I get the same, sure its the tweaking. I put it to cover a larger frequency and it distorts, cut it back and not enough, so just a matter of finding the sweet spot in between, but as I said... stationary and on the move is a different matter, find the bass disappears when on the move and the mid-bass from the front components isn't great, might upgrade those as its a simple fit

[MOB]

Spent ages tweaking last night and I'm almost there - its amazing the difference the dials on the amp make lol

Thanks for everyones input!!

[nmf69]

Originally Posted by MOB

Spent ages tweaking last night and I'm almost there - its amazing the difference the dials on the amp make lol

Thanks for everyones input!!

Please post the settings, for reference only

[illingworth22]

Originally Posted by MOB

Spent ages tweaking last night and I'm almost there - its amazing the difference the dials on the amp make lol

Thanks for everyones input!!

Just one other thing... Try to un-plug the amp then plug it back in again (bit like a re boot). I know this may sound stupid but when I changed the settings on my amp then switched them back it had no effect. I unplugged the amp, re connected it and Hey Presto.