Prasad Karpe
Member
Hi Folks
This is a cross over of my vintage Cosmic COVOX 4500 BS speakers (in the attachment). The speaker is a three way sealed enclosed speaker with all drivers of 8 Ohms. The woofer has got polypropelene diaphragm, the midrange is paper cone & the tweeter is metal dome. I was using this speakers in pair with Cosmic CO-100 Amplifier. The problem is that as my understanding of Hi-Fi increased I started to feel that the speakers are very bright with annoying sibilance. The sibilance becomes evident always with Indian Film Music.
This was the time when I came across this forum. The continued readings from the forum gave me the insight that my amplifier may be the weak link. With the help of my local vendor I upgraded my amp. with an old Yamaha receiver. The sibilance slightly came down. However after listening to some more Hi Fi & with the knowledge I had from the posts in the forum I decided to upgrade from a DVD player to a dedicated CD player. This is also a used gadget, Maranz -4000 CD Player. However I noticed that the low end response of the speakers improved I did not get any help in high end region. I realized a bitter fact of life Ignorance is bliss
After the DIY bug has bitten I started to experiment with speakers. I first covered the area around the tweeter front baffle with foam hoping that the excess high frequencies can get absorbed. Since this did not do the trick, I opened the speaker found that the mid range & tweeter are housed in a separate box. I lined the internal walls with foam sheet but found no respite. Then one fine day I thought that the midrange with paper cone may be the culprit. I then cut off the midrange & started listening to woofer & tweeter only. This considerably improved the low end. I was very happy but the happiness did not last long as I found that once I increased the volume level the ugly sibilance started appearing again.
I then ventured in to mysterious region of Cross Over. I removed the cross over from the box & started tracing the ckt. Since I am more of a mechanical guy it required huge efforts to understand the ckt. & reproduce in a respectable manner.
Now since these speakers carry a huge sentimental value in my life (bought from my first salary) I dont want to scrap & get rid of them. My request to the forum members that can somebody help me to reduce the sibilance from those speakers.
I am thinking on the lines of
1. Employing a BSC to the speakers. However I fear that in doing so it may rob the sparkle which I get with the music.
2. Reducing the power to the tweeters. Here also I think that if by any means if I could able to reduce the power the output as a whole will be reduced & the overlapping of frequencies which is the root cause may not go.
3. Shifting the cross over point so that their remains a definite gap without any overlap between the drivers.
Now here is the stage where I would require help from the Gurus in the forum. Since these are the drivers manufactured by Cosmic as per the label attached on the back of coil, I do not have any other information. The label only depicts COSMIC & 8 Ohms. I dont have any measuring instruments either, but after a close hearing I could make out that due to some cross over problem I can hear male voices both from woofer & the tweeter. Therefore I strongly suspect that the midfrequencies are getting played through the tweeter also.
I dont know whether my understanding is right or not. I therefore want help in deciphering the riddle.
Thanking you all in anticipation.
Regards
Prasad Karpe
This is a cross over of my vintage Cosmic COVOX 4500 BS speakers (in the attachment). The speaker is a three way sealed enclosed speaker with all drivers of 8 Ohms. The woofer has got polypropelene diaphragm, the midrange is paper cone & the tweeter is metal dome. I was using this speakers in pair with Cosmic CO-100 Amplifier. The problem is that as my understanding of Hi-Fi increased I started to feel that the speakers are very bright with annoying sibilance. The sibilance becomes evident always with Indian Film Music.
This was the time when I came across this forum. The continued readings from the forum gave me the insight that my amplifier may be the weak link. With the help of my local vendor I upgraded my amp. with an old Yamaha receiver. The sibilance slightly came down. However after listening to some more Hi Fi & with the knowledge I had from the posts in the forum I decided to upgrade from a DVD player to a dedicated CD player. This is also a used gadget, Maranz -4000 CD Player. However I noticed that the low end response of the speakers improved I did not get any help in high end region. I realized a bitter fact of life Ignorance is bliss
After the DIY bug has bitten I started to experiment with speakers. I first covered the area around the tweeter front baffle with foam hoping that the excess high frequencies can get absorbed. Since this did not do the trick, I opened the speaker found that the mid range & tweeter are housed in a separate box. I lined the internal walls with foam sheet but found no respite. Then one fine day I thought that the midrange with paper cone may be the culprit. I then cut off the midrange & started listening to woofer & tweeter only. This considerably improved the low end. I was very happy but the happiness did not last long as I found that once I increased the volume level the ugly sibilance started appearing again.
I then ventured in to mysterious region of Cross Over. I removed the cross over from the box & started tracing the ckt. Since I am more of a mechanical guy it required huge efforts to understand the ckt. & reproduce in a respectable manner.
Now since these speakers carry a huge sentimental value in my life (bought from my first salary) I dont want to scrap & get rid of them. My request to the forum members that can somebody help me to reduce the sibilance from those speakers.
I am thinking on the lines of
1. Employing a BSC to the speakers. However I fear that in doing so it may rob the sparkle which I get with the music.
2. Reducing the power to the tweeters. Here also I think that if by any means if I could able to reduce the power the output as a whole will be reduced & the overlapping of frequencies which is the root cause may not go.
3. Shifting the cross over point so that their remains a definite gap without any overlap between the drivers.
Now here is the stage where I would require help from the Gurus in the forum. Since these are the drivers manufactured by Cosmic as per the label attached on the back of coil, I do not have any other information. The label only depicts COSMIC & 8 Ohms. I dont have any measuring instruments either, but after a close hearing I could make out that due to some cross over problem I can hear male voices both from woofer & the tweeter. Therefore I strongly suspect that the midfrequencies are getting played through the tweeter also.
I dont know whether my understanding is right or not. I therefore want help in deciphering the riddle.
Thanking you all in anticipation.
Regards
Prasad Karpe