[deepfusion]

Originally Posted by navin

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?

[radek]

Originally Posted by deepfusion

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.

[deepfusion]

Originally Posted by radek

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.

[radek]

Originally Posted by deepfusion

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.

[deepfusion]

Originally Posted by radek

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.

[navin]

Originally Posted by deepfusion

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.

[deepfusion]

Originally Posted by navin

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.

[aravind.anand]

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?

[deepfusion]

Originally Posted by radek

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.

Originally Posted by navin

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.

[navin]

Originally Posted by deepfusion

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?

[deepfusion]

Originally Posted by navin

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.

[navin]

Originally Posted by deepfusion

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.

[deepfusion]

Originally Posted by navin

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?

[navin]

Originally Posted by deepfusion

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.

[deepfusion]

Originally Posted by navin

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.?