Reduced bass on acceleration?

[RobGMN 5,000+ posts]

Running dual subs (final impedance 2 ohms) from a mono Rockford class D 500 watt amp. 4/0 wire direct to battery and ground. New stock (700 CCA or so).
I haven’t been able to verify with measurements, but I can swear that the bass gets momentarily weaker when I accelerate away from a light.

My first thought is voltage sag due to power drawn by ignition system during acceleration, but that is followed by thinking voltage/output should increase due to spinning up the alternator above engine idle. They should balance out.

Aside from Doppler effect due to my incredible 0-40 ETs, any ideas? Anyone experienced anything similar?
Given a D amp relies mostly on voltage and current with little capacitance behind it, could a reasonably sized capacitor help if it’s indeed a voltage/current sag issue?

Click to read more...

 

[spokey9]

A big 3 might help if it is voltage drop

It could also be a sign of a weak alternator...when my wife still had my saturn, at night you could see the headlights dim taking off from a red light...turned out to be her alternator on it's last legs...

 

[HardofWhoring]

Are you sure you're not just going so fast, that the speed of sound is having trouble keeping up?

That's barely using anything. You don't need a capacitor for 500w. That's going to be somewhere around a 40 amp draw. It MIGHT work, but that is 100% not the problem. It might fix the symptom, but that will not fix the cause.

It sounds like it's something more driveline related, where your acceleration is causing a voltage drop, (no matter if that little amp is connected or not). Yeah the alternator is a good guess. The bearings could be going out in the pulley and causing drag. If an older belt, older tensioner, older timing belt, (not sure about that vehicle), it could be loose and slipping, and needs to be replaced.

If you are at speed and floor it so revs all the way up, and doesn't cause this, that should rule out a slipping belt since it's more likely to slip or cause problems at higher RPM (spinning).

Depending on your alt, the amperage output is not going to get to full until over 2K or higher. It's not going to even itself out, or overcome that deficiency until you get it up higher.

You could also see if you can really load your system down and try to make the problem more obvious. Put your highs on, your 4 ways on, AC on high, use your automatic windows if you got em, put something in the cigarette lighter or use an inverter, crank that stereo to full with heavy bass. If you can really stress test your electrical, it might show something.