Go Back   Team-BHP > Under the Hood > In-Car Entertainment


Reply
 
Thread Tools Search this Thread
Old 11th July 2012, 15:01   #301
BHPian
 
Join Date: Dec 2009
Location: Gurgaon,N.Delhi
Posts: 456
Thanked: 116 Times
Default Re: Queries in 'Ask the gurus' section

Quote:
Originally Posted by navin View Post
So this is what I understand
a. The midbass is HPFed at 80Hz
b. You hear the 'krr' at 100hz from the midbass

1. turn the graphic eq to flat.
2. feel the door panel near the midbass or midbass basket/grill and turn up the volume till you begin to hear the 'krr' sound. repeat with various music and report if the sound is more noticeable with different artists.
3. if you can increase the slope of the HPF filter to 18db o 24db.

Does the 'krrr' sound have any harmonics or is it only at 100hz?
I shall undertake the exercise and confirm.

But one thing, the krr is clearly audible at low volume. As the volume increases, the sub suppresses this fault and the krr cannot be easily made out.

How do I increase the slope of HPF filter?
deepfusion is offline   Reply With Quote
Old 12th July 2012, 10:48   #302
BHPian
 
Join Date: May 2007
Location: Pune
Posts: 283
Thanked: 71 Times
Default Re: Queries in 'Ask the gurus' section

Quote:
Originally Posted by deepfusion View Post
I shall undertake the exercise and confirm.

But one thing, the krr is clearly audible at low volume. As the volume increases, the sub suppresses this fault and the krr cannot be easily made out.

How do I increase the slope of HPF filter?
Is this 'krrr' sound audible when you reduce volume to zero? If this noise disappers at zero volume, this can be because of RC shielding problem.
radek is offline   (1) Thanks Reply With Quote
Old 12th July 2012, 10:55   #303
BHPian
 
Join Date: Dec 2009
Location: Gurgaon,N.Delhi
Posts: 456
Thanked: 116 Times
Default Re: Queries in 'Ask the gurus' section

Quote:
Originally Posted by radek View Post
Is this 'krrr' sound audible when you reduce volume to zero? If this noise disappers at zero volume, this can be because of RC shielding problem.
No, the problem of this abnormal sound is audible at vol. levels 3-9 where after it sorts of hide behind the sub's sound.
deepfusion is offline   Reply With Quote
Old 12th July 2012, 11:02   #304
BHPian
 
Join Date: May 2007
Location: Pune
Posts: 283
Thanked: 71 Times
Default Re: Queries in 'Ask the gurus' section

Quote:
Originally Posted by deepfusion View Post
No, the problem of this abnormal sound is audible at vol. levels 3-9 where after it sorts of hide behind the sub's sound.
I had similar problem where the 'krrr' sound is heard at low volume but gets hidden at loud volume. Basically, this noise volume remains constant irrspective of volume level of HU. This was solved by winding copper wire at the point where RC is connected to HU. This wire is grounded to chasis.
radek is offline   Reply With Quote
Old 12th July 2012, 11:16   #305
BHPian
 
Join Date: Dec 2009
Location: Gurgaon,N.Delhi
Posts: 456
Thanked: 116 Times
Default Re: Queries in 'Ask the gurus' section

Quote:
Originally Posted by radek View Post
I had similar problem where the 'krrr' sound is heard at low volume but gets hidden at loud volume. Basically, this noise volume remains constant irrspective of volume level of HU. This was solved by winding copper wire at the point where RC is connected to HU. This wire is grounded to chasis.
I suppose my issue is somewhat different. Initially, I thought it to be a problem with the mid basses. But on DIY effort, I was able to diagnose it as poor and faulty installation by the installer. He has used a raw wooden ring for mounting the mid basses. The rings have not been damped, despite the doors being fully damped. Second, the rings have just been attached to the body, and not properly and soundly secured with screws. Third, there is space between the ring and the door, and ring and the speaker. So, my assumption is, if these aspects are taken care, the sound might go. Else, I have got another set of focals which I plan to substitute.

I shall be doing DIY on these issues, in the light of the suggestions by Navin Sir, on Saturday morning, and shall update you accordingly.
deepfusion is offline   Reply With Quote
Old 12th July 2012, 11:43   #306
Team-BHP Support
 
navin's Avatar
 
Join Date: Mar 2004
Location: mumbai
Posts: 22,194
Thanked: 3,622 Times
Default Re: Queries in 'Ask the gurus' section

Quote:
Originally Posted by deepfusion View Post
But one thing, the krr is clearly audible at low volume. As the volume increases, the sub suppresses this fault and the krr cannot be easily made out.

How do I increase the slope of HPF filter?
turn off the sub. see if the krr increases as the volume increases. is it constant or does it change and why does it change.

Most HUs (I dont know the details for each HU) offer multiple slopes and crossover points. I would suggest using the owner's manual of your HU to get this information.
navin is offline   (1) Thanks Reply With Quote
Old 12th July 2012, 12:03   #307
BHPian
 
Join Date: Dec 2009
Location: Gurgaon,N.Delhi
Posts: 456
Thanked: 116 Times
Default Re: Queries in 'Ask the gurus' section

Quote:
Originally Posted by navin View Post
turn off the sub. see if the krr increases as the volume increases. is it constant or does it change and why does it change.

Most HUs (I dont know the details for each HU) offer multiple slopes and crossover points. I would suggest using the owner's manual of your HU to get this information.
I have planned for a DIT session on Saturday.

I shall report the findings in the afternoon then.
deepfusion is offline   Reply With Quote
Old 15th July 2012, 15:52   #308
Senior - BHPian
 
aravind.anand's Avatar
 
Join Date: Apr 2011
Location: Chennai
Posts: 1,298
Thanked: 1,495 Times
Default Re: Queries in 'Ask the gurus' section

My friend who has a Fiesta is not happy with the performance of his AUX port. He recently got a very good AUX cable as he thought that the low quality cable was spoiling his experience. While the SQ was never bad, the volume of the OEM HU had to be jacked up to 20 to get some decent volume, the same loudness could be reached with 8-9 volume level while playing a CD or through FM.
The same cable, media device, volume on the media device provided fabulous sound at 8-9 volume levels of the OEM HU of the Figo though!

Seeking the advice of the Guru's to help my poor friend. What could be wrong?
aravind.anand is online now   Reply With Quote
Old 16th July 2012, 10:27   #309
BHPian
 
Join Date: Dec 2009
Location: Gurgaon,N.Delhi
Posts: 456
Thanked: 116 Times
Default Re: Queries in 'Ask the gurus' section

Quote:
Originally Posted by radek View Post
Is this 'krrr' sound audible when you reduce volume to zero? If this noise disappers at zero volume, this can be because of RC shielding problem.
Quote:
Originally Posted by navin View Post
turn off the sub. see if the krr increases as the volume increases. is it constant or does it change and why does it change.

Most HUs (I dont know the details for each HU) offer multiple slopes and crossover points. I would suggest using the owner's manual of your HU to get this information.
Thanks, Dear Alte, Radek, Sam Kapasi and Navin Sirs, for your valuable support and suggestions.

The outcome of the DIY session undertaken on Saturday and Sunday, 14th and 15th July, 2012:



The problem has been eliminated.

I have changed the speakers to Focal VB 165.

They are now being powered directly by the JBL GT0604, without any crossover in between.

Front channels of the amp driving the tweeters and the rear channels driving the mid basses. Some fine tuning of the gains remains to be done, but the result is AWESOME. I have never heard the car's music system sound so good.

The sound has become so lucid that you don't miss a beat. Every nuance is reproduced beautifully.

Last edited by deepfusion : 16th July 2012 at 10:29.
deepfusion is offline   Reply With Quote
Old 17th July 2012, 09:38   #310
Team-BHP Support
 
navin's Avatar
 
Join Date: Mar 2004
Location: mumbai
Posts: 22,194
Thanked: 3,622 Times
Default Re: Queries in 'Ask the gurus' section

Quote:
Originally Posted by deepfusion View Post

rear channels driving the mid basses.
no crossover? what protection do the tweeters have? Does the Amp have a high pass around 3K/12db at the least?

Last edited by navin : 17th July 2012 at 09:49.
navin is offline   (1) Thanks Reply With Quote
Old 17th July 2012, 10:14   #311
BHPian
 
Join Date: Dec 2009
Location: Gurgaon,N.Delhi
Posts: 456
Thanked: 116 Times
Default Re: Queries in 'Ask the gurus' section

Quote:
Originally Posted by navin View Post
no crossover? what protection do the tweeters have? Does the Amp have a high pass around 3K/12db at the least?
No protection whatsoever.

I told earlier. I am a student of Nursery class in ICE School.lol.

Seriously, can there be some sort of protection for the tweeters?

If so, can I use the passive crossovers between the amp and the tweeter?

These are being run off the JBL GT50604 on HPF mode, with crossover set at 320 Hz on the amplifier.

Last edited by deepfusion : 17th July 2012 at 10:21.
deepfusion is offline   Reply With Quote
Old 17th July 2012, 10:44   #312
Team-BHP Support
 
navin's Avatar
 
Join Date: Mar 2004
Location: mumbai
Posts: 22,194
Thanked: 3,622 Times
Default Re: Queries in 'Ask the gurus' section

Quote:
Originally Posted by deepfusion View Post
No protection whatsoever.

I told earlier. I am a student of Nursery class in ICE School.lol.

Seriously, can there be some sort of protection for the tweeters?

If so, can I use the passive crossovers between the amp and the tweeter?

These are being run off the JBL GT50604 on HPF mode, with crossover set at 320 Hz on the amplifier.

I am surprised the tweeters have not blown yet. 320Hz is woefully inadequate! 3200hz is more correct.

Tweeters need protection as they are not dsigned to handle low frequencies or too much power. Low frequencies will cause over excursion and mechanical damage to the tweeter's voice coil/suspension, and power would fry the voice coil.

Typically 50% of music's energy (if there is no amplifier clipping or other distortion) is below 300Hz, 75% is below 2500hz, and only about 10% is above 4000Hz. Hence a tweeter of a "100W component system" is designed to handle only about 10W.

A woofer does not need protection from destruction, a tweeter DEMANDS it.
navin is offline   Reply With Quote
Old 17th July 2012, 10:48   #313
BHPian
 
Join Date: Dec 2009
Location: Gurgaon,N.Delhi
Posts: 456
Thanked: 116 Times
Default Re: Queries in 'Ask the gurus' section

Quote:
Originally Posted by navin View Post

I am surprised the tweeters have not blown yet. 320Hz is woefully inadequate! 3200hz is more correct.

Tweeters need protection as they are not dsigned to handle low frequencies or too much power. Low frequencies will cause over excursion and mechanical damage to the tweeter's voice coil/suspension, and power would fry the voice coil.

Typically 50% of music's energy (if there is no amplifier clipping or other distortion) is below 300Hz, 75% is below 2500hz, and only about 10% is above 4000Hz. Hence a tweeter of a "100W component system" is designed to handle only about 10W.

A woofer does not need protection from destruction, a tweeter DEMANDS it.
But how do I protect the tweeters? Would the passive crossovers provide a solution?
deepfusion is offline   Reply With Quote
Old 17th July 2012, 10:52   #314
Team-BHP Support
 
navin's Avatar
 
Join Date: Mar 2004
Location: mumbai
Posts: 22,194
Thanked: 3,622 Times
Default Re: Queries in 'Ask the gurus' section

Quote:
Originally Posted by deepfusion View Post
But how do I protect the tweeters? Would the passive crossovers provide a solution?
Yes!!! the passive crossovers are designed to delvier only that much power the tweeter can handle to the tweeter.

I would connect the amp to the crossover and the high pass of the crossover to the tweeter. Do not connect the woofer yet. First Play music See if the tweetrs still work - you should hear some high frequency sounds. Then connect low pass of the crosssover to the wofoers.
navin is offline   Reply With Quote
Old 17th July 2012, 11:00   #315
BHPian
 
Join Date: Dec 2009
Location: Gurgaon,N.Delhi
Posts: 456
Thanked: 116 Times
Default Re: Queries in 'Ask the gurus' section

Quote:
Originally Posted by navin View Post
Yes!!! the passive crossovers are designed to delvier only that much power the tweeter can handle to the tweeter.

I would connect the amp to the crossover and the high pass of the crossover to the tweeter. Do not connect the woofer yet. First Play music See if the tweetrs still work - you should hear some high frequency sounds. Then connect low pass of the crosssover to the wofoers.
But I had deliberately removed the passive crossovers to get teh max out of the speakers.

For protecting the tweeters, I will put the crossovers.

But do I need the crossovers for the mids also? The HU is HPFed at 80 Hz, the amp is switched to HPF, crossover at 80 Hz, and bass boost at min.?
deepfusion is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Automobile Insurance Queries? Ask me rjvora_2000 Indian Car Loans & Insurance 3871 8th July 2017 16:10
Google SMS - An end to Ask me service ! Sahil Shifting gears 12 30th January 2008 00:05
The Newbie Thread: Things you were scared to ask vidvai Technical Stuff 30 17th August 2007 17:30
P-150 classic for sale .What can i ask for jango Motorbikes 1 31st March 2006 12:51


All times are GMT +5.5. The time now is 10:29.

Copyright 2000 - 2017, Team-BHP.com
Proudly powered by E2E Networks