Aeroplane sound

[Abba]

Bro,

Strange that me stereo has started to develop "aeroplane sound" after 2 yrs. Got an amp, cap & couple sets of component speakers.

 

Any good stereo shops to advice to fix this problem and how much it'll cost to fix?

[Kermit]

My suggestion is change your cap. Caps normally wear out after a while.

[Zoom99]

One highly possibility is amp is gone.

I experience it b4.

[Hungryforcar]

if amp is gone, does it means that all system connected to the amp wont have sound?

[Hyun]

caps? caps are in the power lines .. can also cause aeroplane ah? it's not part of the signal path leh ...

 

i just noticed... kermit got pariah 3-way!

serious. this wednesday must poke poke the phase plug....

Edited November 6, 2006 by Hyun

[Zoom99]

Depends if all yr speakers are connected to amp.

 

Example, if yr amp serves 2 front speakers only then 'aeroplane' sound should not be heard from rear speakers

[Ilovesupremo]

When he meant "gone" , it is the internal part of the amps like resistor or inductor or power supply or etc are not working properly, therefore there are aeroplane sound causes by the amp but there still sound from the speakers..

[Kwongwing]

Aeroplane noise is in fact sound generated in the power lines which causes the noise to be induced in the signal chain - I tink!

Which is why the solution is to tackle the power supply lines - with noise suppressors, etc.

[Kermit]

Thanks KW! Yup...power definitely can cause "alternator whine" (which is the right term to use). So if it's got something to do with alternator, it must be power-related lor...that's what I believe...

[Abba]

Hi Guru,

is there a way to isolate the problem is fm Amp or Cap?

 

Yes, both my front R rear components connected to 1x 4 ch Amp.

 

Will installing noise supressors impact my clarity?

[Yanuk]

*ding dong*ding dong* KW knows your stuff!

[Yanuk]

noise suppressors are usually passive devices, containing coils and caps.. I havne't seen an active noise suppressor for car audio yet. Being passive devices, they will induce some voltage drop.

 

If the problem just popped up in a perfectly fine system , maybe you can read this. http://www.eham.net/articles/15113

[S390u]

Bro,

Strange that me stereo has started to develop "aeroplane sound" after 2 yrs. Got an amp, cap & couple sets of component speakers.

 

Any good stereo shops to advice to fix this problem and how much it'll cost to fix?

 

Bro, I experience this before, besides, when you press your horn it will be worse. I think you install an diode(small conductor), the noise will be gone. very cheap and some shopd not even charge you

[Hyun]

ah .. something like stuff like ground loops etc.. so the effect is - there is some unstable voltage running into the amp. Ground ends up being NOT 0 volts. and maybe input voltage fluctuates. as for power cable induction of noise in signal channels, that falls into the category of electromagnetic liao - the simple act of magnetic waves around the power cable creating currents in nearby cables, generating "sound".

 

i dont know how "alternator whine" works - how does it come about? i've heard it before, though. when i placed many signal wires including my crossover near the alternator (i placed it far forward in the foot pedals region) u hear the whine that varies with RPM.

 

to diagnose whether it's amp or cap, simply remove CAP first, right? if that's not enough, then it might be elsewhere, including amps, cables etc.

 

i haven't seen a noise suppresor before but i remember reading that those in the signal line work simply with caps or a combo to cut out high frequencies. it's simply a low-pass filter, of any order (the higher, the more components), that cuts stuff like 20khz, or 16khz and beyond, including the noise ... and also including ur music!

 

power line noise suppressors, that one i donno. any1 knows how it works?

[Kwongwing]

I NO guru and never claimed to be one.

Easy to check w/r Cap is at fault - merely remove it from your power line.

If that does not help - then you would have to do trial and error - switch your signal cables around from left to right - if the whine also shifts then it is likely your amp or cables connections after the amp

Else just go to your former installer for them to trace.

FYI even the DIYers in the Delphi forums have had good results with the Helix Cap 33 - a noise suppressor. However, one must always try to find the fundamental cause of the whine. The noise suppressor are actually meant to reduce noise to a lower noise floor thereafter.

[Dada]

Any bros here able to help me out? I'm having the same alternator whine. Initially, I tot it was my power cable which was causing the noise. After isolating the power cable, I re-ran the cable on the driver's side, the noise still persisted. Next was the amp, I was using a VDO 4 x 75wrms amp and decided to upgrade. After changing out the amp, the noise got louder. I had to use 2 noise suppressors before the noise disappeared. 1 at the output of my HU and another at the RCA inputs. Currently I'm using the DBDrive 4.120 speed series. I decided not to install the noise suppressors and still scratching my head as to where the noise might be coming from. If it's not the cables or the amp could it be coming from the HU? I'm using the alpine 9855. My installer suspected that my alpine hu could be a lemon. Previously when I was running a passive setup, the noise was non-existant. After switching to active, the noise appeared. Pretty upset and vexed...feel like switching back to passive. Brought the HU which I bought from NH and the boss said it's DEFINITELY not his hu and offered to solve it for me provided I get a new amp from him...He did not even bother to try testing it for me. He even said that the noise was coming from an under powered amp. How can this be?? I made a really big mistake. Shouldn't have gotten the hu from him.. U call this customer service?? More like Really appreciate it. Thanks!

 

My setup is as follows:

Alpine 9855

6.5" Lanzar Opti6C components

DBdrive 4.120 Speed series

Bazooka sub

Alpine 1.200

Running on active setup.

Edited November 8, 2006 by Dada

[User12343]

ha, it appears all those farkers installers are pulling a fast one on u, either that they ask u to commit more $$$ into buying their stuff before they troubleshoot for u....sad

 

the following are some pointers u can consider in hunting down/eliminating the whines:

 

- amp gains must be suitably adjusted and matched so that it does not sound too loud and cause distortion when u crank up the 9855 volume a bit. too high gain introduces hisses and more susceptable to alternator noise.

 

- quality of RCA cables. some cheap/inferior RCA cables do not have sufficient screening to block out electrical noise

 

- disconnect the amp RCA inputs, and check if the whine still present. if its gone, then it might be the RCA cable or the running of the RCA cable. if still present, check the power/ground cables. make sure that all the amps' ground are tied together at the same chassis which has a good zero-ohm resistance return-path to the -ve batt terminal

 

- borrow another amp to try out to see if it still occurs. if noise gone, its the amp, if not, ur original amp is good.

 

- if noise still present, consider adding a alternator noise suppressor which is essentially a high capacitance capacitor tied next to the alternator.

 

there are still many possibilities to tink of.....

Edited November 8, 2006 by User12343

[Hyun]

any idea how it works electrically? this high cap capacitor? if it's working as a filter, which it seems to be doing, sounds like it'll highpass all except the lowest frequencies, at the power line.