Sub woofer pops at low volume

[PMC]

Calling all audio gurus, I need some diagnostic help!


At low volumes, I'm hearing a noise out the SUB Woofer. It sounds like a clipping or a POP

Some background on my setup. I have all the speakers powered from 1 AMP in both the Cockpit and the Bridge of the boat. In the cockpit are the JLs (10" SUB & 770s) In the Bridge I have 6.5 Sony and a 10" Clarion Sub

I wired both subs in parallel (2 ohms) the same channel, and each speaker off its own channel (75W / 4 ohms)

I'm using a singe set of RCA cables from the head unit to the amp.

The sub location is under the couch, but within a climate controlled area. I have not seen any signs of overheating, but I also have not scanned the amp for its temperature.

Here is what I have experimented with so far:

• Running new speaker wire to the sub
• Adjusting the low-pass filter
• Raise / Lower the SUB channel gain
• Eliminating the remote control (configured to control the sub)
• Disconnecting the 6.5 Sony speakers (in the Bridge)
• Disconnecting the Clarion 10' Sub (in the Bridge) - running the JL Sub (4 ohms)

It seems the louder the volume the less noise I hear, but at low volumes (what I call conversation volume) I hear the noise, and ONLY from the SUB. All the equipment is relatively new. Both the head unit and AMP are 2 years old, the JL speakers are a few months old. The bridge speakers are old, but I've disconnected them while diagnosing. What should I test next?

Clarion M502
JL XD700 Amp (wired 75x4 + SUB on 5th channel)
JL HD-RLC Remote (wired to control SUB Gain)

Cockpit Speakers:
Sub - JL 10"
2 x JL 770

Bridge Speakers:
2 x 6.5 Sony (crappy speakers)
SUB - Clarion 10"

 

[Wylie_Tunes]

Are you hearing this noise from both woofers? I would expect so.
Is a random single pop/thump or rhythmic?
Are the in-boats set to full range? If so, whats their cross over point? My guess is, the noise is a frequency below that point. If so, switch them to full pass for a test period. Just be careful playing higher volume. This may isolate it to the woofer side of the amp or amp wide, possibly coming in upstream.
Anything else running on the boat that could omit this noise in tandem with hearing it? Like something cycling on or off when you hear it.

 

[saopm]

Do you have anything plugged in on the AUX side? Bluetooth, TV Audio or such? My Bluetooth creates noise when I connect the 12v power to recharge it. More of a squealing noise. Maybe look into a noise filter. They are cheap and basically just provide an additional ground to the outside RCA conductor. Otherwise, try bypassing the head unit. You should be able to get an RCA output from your phone with the right connectors. Good Luck.