Modifying RX-CT900 speakers has made an incredibly deep bass (from 40 Hz)

Do I need to modify my RX-CT900 Speakers?
As a flagman of Panasonic's boomboxes in 1989 and till January of 1991,
RX-CT900 has a quite decent amp. / ~ 2x30W PMPO /.
I've connected a pair of Technics SB-CS60 ( 8Ohm ) instead of
original 2.7 Ohm speakers and that was a very solid sound with a plenty of trebles ,
mids and bass without noticeable output power loss and distortions were way lower !
Then i've connected them serially along with original speakers and guess what happened?
Sound was even better WITHOUT POWER LOSS AGAIN ! AT 8+2.7 = 10,7 Ohm !
This Amp drives 10 speakers without any problems with less distortions at higher impedance !
This is how i've figured to modify my original speakers for maximum efficiency .
So before you start to modify your boombox speakers , make sure you check it with some
other speakers to see if there's a point to do that.
Some boomboxes have amps designed to work with original speakers only and
any spontaneous modification can affect their good original sound.
Installed are:
Layer of pwc foam, layer of cotton ,
Cross wooden frame/brace/, calculated bass reflex ports
and thick black/red wiring.
Original tweeters were replaced with sensitive high output piezo tweeters,
capacitors installed as well.
Decorative polished chrome rings added to finish bass reflex ports' edges.
Wire organizers were gently released and saved along with original wires
You can always put them back originally with original screws.












Check out my other posts about replacing/adding tweeters and
significantly improving your favorite boombox and your home stereo -
https://www.stereo2go.com/forums/threads/original-ceramic-tweeters-vs-regular-dome-piezo-or-cone-tweeters-do-i-need-to-replace-them.6370/
http://stereo2go.com/forums/threads/modifying-rx-ct980-has-made-a-portable-hi-fi.6332/
https://www.stereo2go.com/forums/threads/combining-your-favorite-boombox-with-any-home-stereo.8548/

Happy listening !
And check my Metal Reel Cassette Tapes here -
https://sites.google.com/view/reelcassettetapes

 

I use Rockmat, it's a cheaper version of Dynamat. It reduces resonance in plastic speakers, and tightens up the bass.

 

Thanks for your attention to my projects!
It's not just a wood parts thing inside the cabinets! I've installed a pair of bass ports on them!
In this particular model I've used just a two crossed pieces of hardwood /not a total bracing/
to ensure that a Basic vibration never goes on , because those speakers are
still the Old School Generation of late 80s and those plastic walls are thick enough.
However ,the PWC and Cotton together can fight any unwanted vibrations/distortions only
when a basic hardwood frame/brace is installed, because I have made those bass ports.
Those Bass Ports produce that necessary firm and deep bass that all 80's boomboxes are missing..

 

You're right, but to cover a wide range of
vibrations - we need a combination of 2 or 3 different materials,
because each of them covers a certain narrow part of the range.
For now the perfect one for all cases is a thick compressed natural wool..
That is a quite expensive thing..and it's hard to find..
I 've used that wool to make my RX-CT 980 speakers /please see my very first post/

 

Sveiki. Kāds ir basa caurules izmērs rx-ct900? Garums var būt 10 cm, ne vairāk, bet kāds ir iekšējais vai ārējais diametrs?

 

Hello! I have sold my RX900 already .
The inner diameter was 30 mm and 65 mm long.
Plus I highly recommend to use a thick / 3-4 mm/ compressed
natural wool fabric instead of foam because this is the best
damping material.
Best regards .

Don't forget to check out my Metal Reel Tapes here -
https://sites.google.com/view/reelcassettetapes

 

Thanks for info

 

Other question, What model of tweeter you used in that speaker modification or what inpedance?

 

Hello .
Sorry for my late respond..
That RX-CT900 was sold
Now I can't remember details , but
I've installed an automotive high impedance piezo speakers
with ~ 25 mm diameter.
Check this out -
https://stereo2go.com/forums/thread...cone-tweeters-do-i-need-to-replace-them.6370/
Regards