vintage sansui s-55c 4 speaker crossover ?

[jamiecantar]

hi guys,

im new here, just joined.

I've started collecting a few vintage pieces and came across a pair of Sansui s-55c speakers from the 1980's era. They are a 4 way design i think. 2 tweets, a mid and a woofer. 80 watts max handling and 8 ohms.

After taking out one of the woofers I noticed a pretty pathetic crossover layout on these speakers. Now these speakers are not the Sansui from the 1970's japan. I think this was the next generation sansui's made by the Orion people. These particular model was made in canada but the drivers all say made in Taiwan. Anyway, I would like to improve the crossover if possible and would welcome any advice. attached is the current layout.

cheers. jamie

 

[picowallspeaker]

Two tweeters, why ?

I would replace them with a new one

Try some Seas DTX - if crossed low ( but I fear not )
it could supply at the job made by the 2*tw + midrange .

Or try a full range...so a FAST design, for better understanding of how good it
would be to put a coil in series with the woofer .

But a 2" can't reach well below 2-300 Hz and hasn't more than 85-87 dB sensitivity ...

 

[jamiecantar]

Hey pico,

did you mean a inductor choke like 2.5-3.0 mH, right after the woofer?

 

[hunter audio]

Vintage Sansui ,

Over the years we ave worked on vintage sansui speakers , we have made dyes from all types of materials to make the beautiful air dried cones cones of these speakers .

We are yet to get the sound from these speakers specially the 15 inch full range loaded speakers .

Suranjan

 

[picowallspeaker]

did you mean a inductor choke like 2.5-3.0 mH, right after the woofer?

Yes, before ...
But it's likely to cross it at 500-600 Hz and with a gentle slope ( 6 dB/Oct)
So you'd want a modern midrange that's able to reproduce well also the treble
Just see how it lowers the efficiency (it also adds some resistance...) ...
This only if you want to play at higher power . So also 2nd order with lower value coil .

 

[adason]

looking at it, sansui was competing for "minimum parts" crossover prize

 

[jamiecantar]

oh geeze,

i'm not much of an audio engineer, a simple sketch would really help me out.

cheers

 

[picowallspeaker]

But first you need some components, to try.
At Sansui they did fine ( If they sound so) because if the speaker accomplished
in the duty it didn't matter how. Just for the money side; so my guess was
that those speakers became sort of 'metallic' when turned up playing at high
volume. Probably 'metallic' can be swapped with 'mechanical filter' which is
how a speaker works...so a speaker already has its own 'natural' band and it's mainly determined by its diameter, and it has maximal efficiency within it's
'pistonic band'. So a simple crossover may work but...it has speakers attached!
So the first thing to do, among the others ...is to give a reasonable limit to
the workable band of the woofer . While doing this, thinking also how the cutted band would be reproduced . I suggested the FAST approach ( use...search...something like'Tysen' ) which is the same idea but inverted Having a little fullrange which is ( mechanical filter ) physically limited to reproduce the low frequencies, and a woofer that is in the same situation- but inverted
If you have some PC multimedia kind of speakers you can try with those.

Or if you feel for a more specialized component, try a dome tweeter.
A silk dome !
In this situation, the point of conjunction between the components, the crossover point, which must be -3 or -6 dB for each to have a flat response resulting from summation -and depending also upon position, if close - the crossover frequency would be quite high .Yes I'm talking about a classic two-way ! Modern tweeters have a very low resonance frequency . The
ones with ferrofluid are fine to be used with a 6 dB/oct filter -just a capacitor
The values of the components for the filter would be then a < 1 mH coil
and a <10 uF capacitor THIS VALUE KILLS tweeters