• Hello and Welcome to HiFiVision.com - an online community for the home entertainment and tech enthusiasts!

    If you would like to ask a question, participate in a discussion and view attachments please Register yourself.

Do Subwoofers make a loud thumping noise when powered on?

AV Cables

saketb

Well-Known Member
Joined
Aug 30, 2010
Messages
1,054
Points
83
Location
Bangalore
Well as the title says, I wanted some insight on this thing.

My Polk Audio DSW PRO 550 makes a loud thumping noise (like subwoofers do) whenever the power is switched on. I thought maybe, it was due to some electrical interference, so bought a V-Guard Digi 200 and connected along with it. Even now after its connected and powered on the issue remains the same.

I am wondering whether is it normal or there is some issue with the sub.

Request some help as the sub is in warranty period and I can get it repaired or replaced.
 

Amitkg

Active Member
Joined
Jul 2, 2014
Messages
490
Points
43
Location
Agarpara, Kolkata
Well as the title says, I wanted some insight on this thing.

My Polk Audio DSW PRO 550 makes a loud thumping noise (like subwoofers do) whenever the power is switched on. I thought maybe, it was due to some electrical interference, so bought a V-Guard Digi 200 and connected along with it. Even now after its connected and powered on the issue remains the same.

I am wondering whether is it normal or there is some issue with the sub.

Request some help as the sub is in warranty period and I can get it repaired or replaced.
Make sure that when you power down the sub, first turn sub-woofer switch(on the back of sub-woofer unit) off, then you switch off the wall-socket (in your case V-Guard) switch. When you power-on,, do the reverse
 

spirovious

Well-Known Member
Joined
Apr 10, 2008
Messages
12,350
Points
113
Location
Mumbai
My Polk Audio DSW PRO 550 makes a loud thumping noise (like subwoofers do) whenever the power is switched on.
I have same SW and it doesnt make that loud noise if AVR is switched on early and then subwoofer with AVR volume zero.
 

thampi

Active Member
Joined
Apr 2, 2014
Messages
183
Points
28
Location
trivandrum
thumping noise can come from amplifier too.normally subs wont produce thumping noise.
 

elan13

Member
Joined
Nov 1, 2012
Messages
52
Points
8
Location
Navi Mumbai
My polk sub also make noise only if i forget to turn down the AVR volume before powering it off.
 

saketb

Well-Known Member
Joined
Aug 30, 2010
Messages
1,054
Points
83
Location
Bangalore
Make sure that when you power down the sub, first turn sub-woofer switch(on the back of sub-woofer unit) off, then you switch off the wall-socket (in your case V-Guard) switch. When you power-on,, do the reverse
I tried the way you said but it still makes that noise.

I have same SW and it doesnt make that loud noise if AVR is switched on early and then subwoofer with AVR volume zero.
Its quite surprising that mine is making such loud noise when powered on. I tried with volume zero on the receiver and switching on the sub, but its the same thing. I keep the sub in stand-by mode.
One thing I noticed is that when a power on-off cycle is done to the sub withing a minute it does not make any noise and turns on quietly. If I leave it for a longer time duration and power it on it makes that same noise.

thumping noise can come from amplifier too.normally subs wont produce thumping noise.
I've even removed the RCA cable and checked, even then the same loud noise, so the amplifier thing is ruled out.
 

vkirti

Active Member
Joined
Mar 28, 2010
Messages
196
Points
28
Location
Delhi, India
I have a similar issue with a PSW 110. In fact i asked the dealer about it and he did not know. There is a "Thud" sound on switching on the subwoofer irrespective of its connections. It is almost as if there is no relay to delay the output to the woofer as is the case in standard amplifiers.
 

kneo

Active Member
Joined
Jun 19, 2009
Messages
683
Points
43
Location
Mumbai
I have a lowly Astonia but I too experience this irrespective of the input connection.
 

vkirti

Active Member
Joined
Mar 28, 2010
Messages
196
Points
28
Location
Delhi, India
I have a lowly Astonia but I too experience this irrespective of the input connection.
Considering that the PSW 110 which I have costed less than your "Lowly" Astonia, i will henceforth call her "Lowliest" :lol::lol:

Laughs apart, do other people with better SW's also experience this sound on being powered on ? In my case it has been present since the beginning.
 

BLASTO

Well-Known Member
Joined
Mar 23, 2009
Messages
3,547
Points
113
Location
Hyderabad
My Martin Logan depth is connected via RCA to AVR and also to stereo amp via speaker inputs.

No thudding sound.

Try keeping the sub volume to 1/4 to 1/2 and calibrate AVR accordingly.
If you keep sub volume close to full, it will thud irrespective.

As an experiment, try to reduce the volume fully in the sub volume control and cold start. If it thuds, it is a lemon.
 
Last edited:

Vijay KD

Member
Joined
Nov 23, 2009
Messages
69
Points
8
Location
Chennai
Hi,
Remove the RCA cable from receiver. Switch on Sub, check the noise is there or not and then touch the RCA socket needle, it make some sound. That is normal.
Connect the RCA to receiver, if it makes any sound after connect with receiver then the problem with your receiver output.
Just clean the receiver output with some rust remover and then try again. It may solve the problem.
 

TheSeeker

Active Member
Joined
Oct 25, 2011
Messages
998
Points
43
Location
Thane/Mumbai
i have an F&D system (F5090) connected to my media player, and if i power it up first and THEN power on the media player, the amp/sub makes a loud noise like a thud. similarly, if i power off the media player BEFORE turning off the sub/system, again the same noise. i have thus become careful to be mindful of this when switching on these devices.

though on my PC 5.1 speakers (DA5000 Pro), irrespective of whether my console/PC is turned off or on, the speakers (rear) make a short, 'switching' sound. only the magnitude of the sound varies, depending on whether the source (PC/console) is turned on or off prior powering up the speakers. after happening once, it doesn't occur again during the whole time, howmuchever i turn the speakers on and off, until i have turned off the source itself for sometime; its as if the amp/sub of the speakers make a cold start and then get 'warmed up'.
 

saketb

Well-Known Member
Joined
Aug 30, 2010
Messages
1,054
Points
83
Location
Bangalore
First of all, thanks to everyone for their inputs.

Oh... looks like, many of the members are facing the same issue of the sub making a "thud" noise when powering it on.
So, I decided to call up ProFx service centre and requested a technician to visit my residence and finally he turned up today. As I was aware that the guy was coming today for checking up the sub, I did not turn it up since morning so that when I switched it on in front of him, it would definitely make that thud noise.

Well, he came, I switched it on, and it made that same noise. He checked all the connections and called up his superior for clarification. The engineer on the phone told me to put the sub in "Always On" mode and refrain from using Stand By or Auto. He also explained that the charge left in the capacitor discharges the current when switched on which makes the sub's speaker to make that thud noise and that it is normal. He said that if I kept the sub on "Always On" mode, the thud noise would not arise and it would be a silent start.

Now, I've to wait till tomorrow morning to check the same, as my wife is very angry for not letting her listen to music and watch movies. Shall update tomorrow...
 

saketb

Well-Known Member
Joined
Aug 30, 2010
Messages
1,054
Points
83
Location
Bangalore
Well, I powered on the sub with Always On mode and it made the same loud thud.

So, it's clear that either the subs from Polk Audio make that noise when powered on or my particular sub is with an issue. Lets see what the guys at ProFx Service have to say.
 

saketb

Well-Known Member
Joined
Aug 30, 2010
Messages
1,054
Points
83
Location
Bangalore
An Update....

Was playing around with different options on the back of the subwoofer. So, I put the sub on "Stand By" mode (I was using "Auto" before) and switched it on and the sub went in stand by mode with no noise at all. But each time I've to use the remote to bring it out of standby mode and power it on.

At least this way that loud thud can be avoided.
 

saketb

Well-Known Member
Joined
Aug 30, 2010
Messages
1,054
Points
83
Location
Bangalore
A Final Update...

Took the subwoofer to ProFX service centre and showed and explained the issue. The service engineer was friendly and tested the sub throughly and said that it is a common thing happen. He said the same thing regarding the discharge of the capacitor and said it is normal to happen.

Then he himself, asked me if I would like to get the amplifier assembly board replaced as a good gesture for I had taken the sub myself to the service centre & my warranty also was almost going to be over. I got it replaced and viola, the issue has been resolved. We waited for like 30 minutes and turned it on, there was no loud thud and only a quite start.

I am very happy to see that the sub was not making any such noise.
 
Top