Advice on upgrading cheapish old speakers

[TomHaitch]

Hello! Long-time lurker, first time poster, here

I have a pair of non-branded speakers I bought off a neighbour 15 years ago. Looking for a project, I recently broke them open wondering if I could upgrade them, as they've seen better days. The cones have tears and dints and they're sounding maybe sibilant at the top and boxy to the bottom.

I opened them up to find they have 8" Realistic 40-1286C midrange drivers and Foster 065N0500 3.5" tweeters (which I cannot find any info on).

I'm not experienced enough with crossovers to comment on what is there, but I have included photos hoping someone here can!

Would anyone have any advice on where to get started with upgrading and repairing these? I really love the cabinets and they sit on custom built shelving so it'd be a shame to just replace them!

Thanks!

 

[TomHaitch]

Here are the photos of the crossover.

 

[PeteMcK]

replace any electrolytic capacitors. The woofers are high Q, so best in a closed box with plenty of stuffing, should improve the 'boxy' sound. try closing off the port (literally, put a sock in it!)
I have a pair of those woofers virtually new if you want them (free!!), pm me your address, glad to send them to a good home

 

[AllenB]

These look like they may have potential. The drivers look adequate. The crossover is a little better than some, you might be able to build onto it.

The boxes may be contributing. Play some bass and feel the walls. Look whether there is sufficient soft damping inside. I agree with Pete about sock testing.

Planet10 is a member here and knowledgeable about Foster drivers. These go back, and continue today as Fostex. You want to know how low you can take them and how to cross.

In the mean time, find out whether the sibilance is caused by the tweeter or the woofer, or by the difference between them.

 

[PeteMcK]

FWIW, my TS Parameters, measured some years ago...:
Fs 52; Re 7.6; Qe 1.43; Qm 6.06; Qt 1.16; Sd 214; Vas 48; eff 89

 

[ewollowe]

I just finished fixing up a cheap set of sonys for a friend.

Stuffing makes a big difference, I found it cheaper to buy a few cheap pillows at kmart for their polyester than a bag of stuffing at a craft store.

 

[aperiodic]

replace any electrolytic capacitors. The woofers are high Q, so best in a closed box with plenty of stuffing, should improve the 'boxy' sound. try closing off the port (literally, put a sock in it!)
I have a pair of those woofers virtually new if you want them (free!!), pm me your address, glad to send them to a good home

If you have a second pair of same woofers, put them on the back of the box, push-pull connection.

 

[phivates]

The box is not big enough for that to work well IMO.

 

[TomHaitch]

The woofers are high Q, so best in a closed box with plenty of stuffing, should improve the 'boxy' sound. try closing off the port (literally, put a sock in it!)

Awesome, thanks for the info - just how much stuffing is 'plenty'? Like, there is a bunch in there, but it's not crammed in. Should it be stuffed full and packed in?

I have a pair of those woofers virtually new if you want them (free!!), pm me your address, glad to send them to a good home

That is so kind! Thanks, I will in a sec!

replace any electrolytic capacitors.

Ok awesome, I will - does this look like a correct replacement?
3.3uF 50V Bipolar Electrolytic Capacitor | Jaycar Electronics

These look like they may have potential. The drivers look adequate. The crossover is a little better than some, you might be able to build onto it.

The boxes may be contributing. Play some bass and feel the walls. Look whether there is sufficient soft damping inside. I agree with Pete about sock testing.

Thanks! What should I be feeling for on the walls?

I just finished fixing up a cheap set of sonys for a friend.

Stuffing makes a big difference, I found it cheaper to buy a few cheap pillows at kmart for their polyester than a bag of stuffing at a craft store.

I was reading your thread and learning heaps. Thanks for that, that's a good tip. As above, just how much stuffing is enough? Jam it full?

Thanks for all of your help, everyone

 

[TomHaitch]

Actually, have done a little more reading, it looks like these might be the caps for me?
3.3uF 250V Metallised Polypropylene Crossover Capacitor | Jaycar Electronics

 

[PeteMcK]

Yep, those caps are better, won't ever need replacing again.
Sounds like there's plenty of stuffing, more than ~30% is probably too much, but go with whatever sounds good
What's the diameter of the hole for the tweeter?

 

[PeteMcK]

Just remembered a common tweak for these was to tuck a small strip of polyester stuffing behind the center HF cone on the woofer. The idea is to damp the HF from that cone, which isn't really needed because you've got tweeters. May help with the sibilance,. Easy to try & reverse if you don't like it.

 

[picowallspeaker]

That's the so-called mechanical crossover.
Still puzzled by woofers with enormous dustcaps

 

[Moondog55]

Actually, have done a little more reading, it looks like these might be the caps for me?
3.3uF 250V Metallised Polypropylene Crossover Capacitor | Jaycar Electronics

Jantzen Cross caps sound better and are cheaper but you have to pay for postage. Buying from SpeakerBug supports somebody who supports DIY in Australia something that Jaycar don't really do anymore

 

[AllenB]

Should it be stuffed full and packed in?

Acrylic dacron should be lightly packed, a little over 100% fill. Fibreglass can be stacked at around 50% fill.

What should I be feeling for on the walls?

Vibrations. Some will be carried to the panels via the air in the box, some will come straight from the woofer basket mount. This is most effective with a signal generator.

 

[Moondog55]

That signal generator can be a computer program such as Audacity with outputs to a small amplifier

 

[ewollowe]

Awesome, thanks for the info - just how much stuffing is 'plenty'? Like, there is a bunch in there, but it's not crammed in. Should it be stuffed full and packed in?



That is so kind! Thanks, I will in a sec!



Ok awesome, I will - does this look like a correct replacement?
3.3uF 50V Bipolar Electrolytic Capacitor | Jaycar Electronics



Thanks! What should I be feeling for on the walls?



I was reading your thread and learning heaps. Thanks for that, that's a good tip. As above, just how much stuffing is enough? Jam it full?

Thanks for all of your help, everyone

Initially I had it very tightly packed, the woofer actually sat proud of the enclosure such was the amount of stuffing. I think this was a little too much and removed some foam side sheets to allow the pillow to rest a little more loosely and I think this let the sound bloom a little more.

 

[TomHaitch]

Thanks everyone!
So, I replaced the caps, stuffed foam in the ports and rejigged the stuffing (just reworked what was already in there in the end) and they sound infinitely better! Nice full bottom and no longer boxy and hollow sounding. I wouldn't describe any overly sibilant tone anymore, either. Thanks for all your help.

I'm looking into those Jantzen caps, thanks Moondog. Just went to Jaycar cause I was excited to get moving on it!

Next Q - the treble, although not overly sibilant, is maybe slightly more forward than I'd like, and of course, I can just EQ them from the amp, but I wonder if there's any way to tone it back mechanically or with the circuitry?

The tweeters are pretty hammered - I wonder if there's something I could replace them with?

Thanks again.