Carver DSP - Poor sub volume

Pk199 · Post by **Pk199** » Fri May 10, 2013 4:41 pm

Hi

I was hoping you might be able to help me with a problem. I've got a 2004 3.0i SE with the carver DSP and the subs behind the seats. I remember thinking they were ridiculously (prob unnecessarily!) loud when I bought the car but about a week ago the subs were suddenly very quiet. I've taken the grills off the speakers and if turned up the volume + bass (with the fader to rear), I can feel + see some good movement in both cones, but no real volume.

So, I figure there's a signal (digital) going from the head unit to the amp and some form of output to the subs, but nothing like the amount it should be. I'm guessing the problem is the amp. The amp itself is dry (visually - I'll remove it this weekend if I can and check for staining etc), and the fuses (47+51 I think) were normal in the glovebox.

I've been unable to check the 30A fuse on the amp itself yet, but I presume that's fine as all the other speakers (inc the rear tweeters) are working fine.

My questions are:
1. Has anyone else had this and how did they fix it? I'm guessing amp replacement, but that's not a lot of fun price wise
2. Would the amp just lose two channels (I'm presuming both the subs are driven individually, although it'd make more sense if they shared one channel). The output to all 8 other speakers is fine. In fact overall it sound pretty okay, it's just that I know it sounded better before!
3. Any idea why there's still some output and not none at all.

Thanks for all your help - LOVE this forum - it's helped me with so much with the car.

Thanks
Prav

yg54sg · Post by **yg54sg** » Mon May 13, 2013 2:04 am

have the exact problem, as its been like this for years. On occasions the bass will rattle your teeth out even with the roof down, ive been on the motorway and thought wow this system rocks I can still feel bass at 70 with the roof off .... but same song another day, same settings and no where near the same sound.

If you set your fader to the rear, turn up the 60hz in the DSP and play some rnb/hiphop, turn all other frequencies off, turn treble off , whip the grilles off you will notice those subs are working fairly hard however the enclosures they sit in are not designed well enough for those deep frequency so in order to pump out any decent thump or movement of air they need some decent power. When you sent the balance to the front the subs in the kick panels are doing 95% of what you can feel and hear in terms of bass. I think you are correct in saying that they are not getting the full level.... the question is where is that loose wire or what causes the lack of power.

I was hoping one day to come on a meet and listen to some other members Z4 with carver use same settings to determine if I actually have a problem like you or if its some kind of acoustic phenomenon such as windows being down causing air pressure or source selection..... just seems weird its intermittent..... some days great bass, other days the bass is acceptable.

Ste · Post by **Ste** » Mon May 13, 2013 9:00 am

Sometimes I get similar to what you describe. If I go on the audio settings and put the bass down then back up it fixes it.

Marius · Post by **Marius** » Mon May 13, 2013 12:34 pm

Ste wrote:Sometimes I get similar to what you describe. If I go on the audio settings and put the bass down then back up it fixes it.

+1

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yg54sg · Post by **yg54sg** » Mon May 13, 2013 10:31 pm

Interesting, i'll give that a try sounds like might be a software issue where the display is showing one thing and the amp doing another.... When you say bass do you mean the bass treble controls or the 60HZ lowest frequency on the DSP?

Pk199 · Post by **Pk199** » Wed Jun 12, 2013 9:30 pm

Hi All

Just wanted to bump this - although the stereo really didn't sound too bad, I did the most foolish thing and bought another amp (from Lithuania!). The new amp gives the same problem but with some added hissing (I think an amp issue). I'm starting to think I'm going crazy and the subs are doing what they're meant to.

I was hoping one of you guys with the Carver set up might test something for me - would you mind fading the stereo to the rear output and tell me if the subs work?

I turning the bass down to minimum and back up again (both on the DSP and the tone controls) but that hasn't made a difference.

Thanks again for all your help.

yg54sg · Post by **yg54sg** » Wed Jun 12, 2013 10:33 pm

the rear subs do work when you fade to rear but at a low volume and very very low frequency so try playing some rob/rap

.... again summer now roof off and the bass is pounding! I am really am starting to think the amp knows when the roof is down

GregZ4 · Post by **GregZ4** » Wed Jun 12, 2013 10:52 pm

Who needs bass to hear James Naughtie in the morning and Nicholas Parsons in the evening?
I want to hear the car anyway.
Put on some rap? Please!
Do you nod in time and wear your cap backwards?
Maybe you need loud stereos when you drive a ragtop. Try a coupe. So much more refined and you can't hear the abuse at traffic lights even if the bass is struggling...

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yg54sg · Post by **yg54sg** » Wed Jun 12, 2013 10:52 pm

you will see the rear subs move rather than hear anything so taking covers off is vital when checking. To be honest I am pretty confident that 95% of the good bass and even some sub is coming from the front carver subs. Those rear subs hardly do anything. I did a fade to the front when the bass was sounding pounding the other day and there was only a small drop in sub. The front bass/subs have been designed very well.

NeilP · Post by **NeilP** » Wed Jun 12, 2013 11:03 pm

I've no idea how the dsp system works but is there an option for adjustable crossover points?

Your issue seems to be that you're just geting woofers that are flexing (low frequencies) and probably have the more audible frequencies turned off

My only other thought is that you're eq settings (and source music for that matter) must be high to the point of clipping. So the system thinks it'll be clever and re-eq everything. I know on the e60's that there is an option to completely turn off the adaptive eq.

Based on what others are saying, it seems that the carver system is being used at it's absolute limit (as set by BMW).

I'd be interested to know if swapping to an aftermarket headunit would cure this problem (not as a permanent fixture as they certainly do ruin the aesthetics of the Z4 dash IMO)

wattsie · Post by **wattsie** » Wed Jun 12, 2013 11:10 pm

NeilP wrote: I'd be interested to know if swapping to an aftermarket headunit would cure this problem (not as a permanent fixture as they certainly do ruin the aesthetics of the Z4 dash IMO)

Changing to an aftermarket heaadunit seems to have cured this on mine. This would lead me to think that its actually a head unit problem.... BUT.... The only way I found to fix this 'loss of sub power' before the swap was to completely disconnect the carver amp and then plug the connector back in, bolt back down and sorted...which points to an amp issue!

As for the aesthetics.. I'm busy working on that, and think I have a cure... watch this space.....

wattsie

yg54sg · Post by **yg54sg** » Wed Jun 12, 2013 11:27 pm

How have you fed the carver amp from the aftermarket head unit? I thought it all went down the BUS digitally with the DSP integrated etc?

wattsie · Post by **wattsie** » Thu Jun 13, 2013 7:45 am

The audio bus might be true on later models, or ones with nav screen maybe, i havent pulled one apart, but thats not the way it works on my '03!

The cd changer is fed into the carver amp digitally through a coax car, but the head unit uses the bus to wake the amp and control stuff like speed volume etc. the actual sound comes through channels from the back of the head unit just like an RCA connection on an aftermarket head unit. I've got a thread on here about it, it's still a work in progress but it works!

Wattsie

Scaramanga · Post by **Scaramanga** » Mon Mar 14, 2016 5:20 pm

Thread resurrection!

Anyone else have this issue or manage to resolve it ?

Scaramanga · Post by **Scaramanga** » Thu Mar 17, 2016 6:20 am

So apparently it looks like the cause of the low volume could be the cut-off from the internal amp is set too low. Anyone else get to the same conclusion ?

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