My Speakers THUMP

[kdickson]

Hi.

I recently purchased a BMW Z3 2.8L roadster - which I love. However, when I turn up the stereo (which was upgraded) I get an annoying thumping sound from the two speakers located by the drivers and passengers feet.

Has anyone experienced this? And any thoughts on how to remedy the problem would be appreciated, because summer cruising is on its way.

[el.duderino]

However, when I turn up the stereo (which was upgraded) I get an annoying thumping sound from the two speakers located by the drivers and passengers feet.

Has anyone experienced this?

No, I've never been in your car.

But I question the actual upgrade performed. What did they do?

[kdickson]

The upgrade was "a New CD Player was put in". When I turn it up quite loud the speakers thump.

[Kompressor]

Your speakers can't handle the power of the new headunit I'm guessing.

[7il]

Naming the brand and model of the "new cd-player" would help.
Also try to describe this "thumping" you hear.

[el.duderino]

Is it a BMW headunit? Or aftermarket?

I suspect aftermarket...

[kdickson]

The Unit is a Clarion DXZ845MC and the Thumping Sound appears with lots of bass and I thought the speakers were blown??

[el.duderino]

OK, thanks, one more question - where is the bass setting on the Clarion CD when the thumping starts happening? Is it up high or at center?

[kdickson]

It is in the middle of the range. The other speakers are fine and do not have this problem

[el.duderino]

I suspect that what is happening is that the speaker outputs of the Clarion are going into the inputs of the BMW amp, and at higher volumes the inputs are being "clipped", and the front speakers are trying to play a DC flat-line signal.

I suspect that the installer needed to use some sort of SVEN or something like that.

Anyone else think that's it?

[Daved]

I'm with el.duderino, the stock amp was made to handle the output of the stock headunit.

I killed my stock amp with an aftermarket (VW Clarion) headunit.

[kdickson]

Thank You. Do you have any suggestions on what I need to do/purchase to rectify the problem.

[Daved]

Thank You. Do you have any suggestions on what I need to do/purchase to rectify the problem.

New amps and speakers. I guess that's not what you wanted to hear but I'm in the same boat, I just ordered my new speakers and I'm still looking for an amp.

[kdickson]

Why new speakers?

Is there some sort of CD player that would work with the BMW unit?

[Daved]

Why new speakers?

Because the stock speakers were made to work with the stock amp which has built-in crossovers.

[kdickson]

This is new to me. What are built in crossovers?

[E53BimmerJunkie]

This is new to me. What are built in crossovers?

Inline crossover's that cut off at a predetermined frequency. This is in place so that low frequencies never make it to your mid ranges and tweeters. Same could be said about a sub's crossover which would cancel all high frequencies. This all prevents damage to speakers and utilizes the speakers as they are intended to be used.

[el.duderino]

You can also get Peripheral SVEN adapter for like $50-60 and get it installed correctly.

[kdickson]

If I get a peripheral SVEN adapter installed will that fix the problem? Or do I need to still buy new speakers/amp??

[Daved]

If your stock amp is already tosted, Peripheral SVEN isn't going to help much now.

[el.duderino]

If your stock amp is already tosted, Peripheral SVEN isn't going to help much now.

Probably not toasted.

[gmcgann]

The thump is usually caused by the speaker cone moving too far, and when the cone hits the end of the suspension travel you get a thump. This is caused by one of two things. The first is you are overdriving the speakers with too much power/bass. Solution - turn down the volume/bass or get speakers that will handle that level. The other reason is that the speaker is "blown" and allowing overexcursion with a normal amount of power. Solution - replace the speaker.

The amp is probably okay. If you overdrive the inputs of the amp it will distort, not thump. If there is no distortion, the amp should be fine.

[el.duderino]

The thump is usually caused by the speaker cone moving too far, and when the cone hits the end of the suspension travel you get a thump. This is caused by one of two things. The first is you are overdriving the speakers with too much power/bass. Solution - turn down the volume/bass or get speakers that will handle that level. The other reason is that the speaker is "blown" and allowing overexcursion with a normal amount of power. Solution - replace the speaker.
.

Actually, I have to say wrong and wrong.

If the amp is getting DC on its inputs, the speaker is thumping as it reaches the limits of its travel for the same reason that it thumps with a 9V battery across the terminals - the amp is TELLING it to thump!

Get rid of the clipping inputs, get rid of the thump.

[gmcgann]

I have never heard an amp that was clean right up until it started clipping. If there is no distortion just before the thump, there is no clipping.

[e34]

Its the amp, I changed my head unit and I lost the base it was just hard thums but I changed the amp and my sound went back to sweet. Those 5.25in speakers do have a interesting kick to them. But change the amp and you should be good.