Mods to Bookshelf Spkr - Replacement Woofer, Damping

[VSTEREO]

Hello to all,

Midbass (woofer) of my Bookshelf speaker has gone kaput recently. It is BPL brand and served very well for 15 years. I am looking forward to replace the midbass for both Left and Right speakers.

Coming to the issue, the cutout measures 14 cm (5 1/2" inch) as shown in the attachment but not many woofers comes in this size. Peerless India (DIYAudioCart) has got few models in 5 1/4" and next available size is 6 or 6 1/2" so struggling to find the replacement. Have checked local Rtchie Street but brands like Dainty though have 5 1/2" but sounds bad. Could someone advice what modifications are required to best fit 5 1/4" into this box ? Or, I am fine if someone can point me to 5 1/2" woofer available at the cost around 1K (per piece).

Thanks,
V

 

[greenhorn]

I think 5.25 should fit.
check this thread for budget options in 1k
http://www.hifivision.com/diy/61434-good-local-driver-brands.html

why not try rewinding it - should cost only a few hundred rupees

 

[VSTEREO]

Thanks greenhorn..

5.25" drivers measures only 12.x cms so not sure if it fits into the box. In the link that you have referred speaks about the availability of surplus drivers from sansui, Panasonic may I know which shop(s) I can find those from ?

In case if I buy 5.25" and it doesnt fit, what kind of modifications might required for the box to fit 5.25" ? Need to replace complete front face of speaker is the only solution ?

Thanks,
V

 

[greenhorn]

I've found that the differences are academic, and more often than not, the drivers are an exact fit, and even the holes may line up.

Since the box is small, why not take it with you to ritchie and try out the woofers they have

I'm not able to figure out how the original woofer was installed, and the problems related to fitting a new speaker based on the image you've posted

 

[VSTEREO]

The factory fitted woofer was mounted from inside (3 screws) and the plastic bracket that we see (in picture) around the woofer cutout is just for cosmetic purpose. As far as I know, mounting from inside is not considered to be a good method so I would like to remove this plastic bracket and mount replacement woofer from outside.

For this reason, I am afraid that 5.25" may not fit properly. I have visited few shops in Ritchie street a month back but it was only 2 or 3 shops (thanks to Chennai summer) and not satisfied with the woofers shown. Any shops which has got good reputation in this business?

 

[Vinay2013]

If cut out diameter is five and a half inch there should not be a problem in mounting a 6" or 6.5" driver. It should be easily mounted from front. You can use some sand paper or file if they are little tight. as per my experience, a 6 or 6.5 inch have 5.25" to 5.6" cut out area but there may be difference in different drivers. Not sure how will you fit a 5.25" in a 5.50" cutout area.

 

[VSTEREO]

If cut out diameter is five and a half inch there should not be a problem in mounting a 6" or 6.5" driver. It should be easily mounted from front. You can use some sand paper or file if they are little tight. as per my experience, a 6 or 6.5 inch have 5.25" to 5.6" cut out area but there may be difference in different drivers. Not sure how will you fit a 5.25" in a 5.50" cutout area.

Thanks much Vinay.. Happy to hear that 5.5" cutout can accommodate 6.5" drivers too. I was under the assumption that cutout diameter is directly proportion to the driver size and hence the confusion.

I may have to have a closer look at the box to see if there is a space left to sand/file if 6.5" is tight.

 

[VSTEREO]

Hi,

I am in need of your help again. The crossover of this speaker is looking to be 1st order and attached the same. Is it possible to identify the crossover point by just looking at the crossover board ? 2.2 uf cap is used for tweeter. Internet search by 2.2uf tells me that 9000 Hz is the crossover point but I haven't heard bookshelf's being crossed that high.

 

[VSTEREO]

Hi All,

I had a good time last weekend working on this. I wanted to damp the speakers so used eggcrate foam and poly. Eggcrate foam went to back of speaker and sides(4 nos.) were lined with Poly. Attached the pictures. I can sense a considerable amount of improvement in sound clarity. I am working on some ideas for the front face(of the speaker) which is going to be next.