A year or two ago I was searching Ebay for boomboxes and
came across a box that caught my eye. It was another
component box that had large bass vents on the back of the
speakers. The speakers themselves were a little unusual
because they were flat and square. It was the Pioneer CK-5.
I ended up winning it for a song. It was a nice warm day
when it arrived so I unpacked it and carried it to the
picnic table in the backyard. I ran a cord over, plugged it in
and tuned to some hip hop station.

I cranked it up a bit and was stunned by the bass output!

It was literally vibrating the whole picnic table. This
box was delivering bass on a Telefunken Studio 1 level
yet it was just half the size of a JVC PC55.

















After about one minute of loud volume the bass was lost and
the speakers began rattling violently! The surrounds had failed.
The surrounds were initially intact but after my short but
loud test drive they crumbled and that was the end... for now.

Getting replacement surrounds for these speakers is not
possible. So after allot of thought and some trials and
errors, I made my own square surrounds. The process is
quite time consuming and tedious but the end result is
well worth it.


Here's a brief step by step illustration of the refoam process.


Notice the rotted surround around the white rectangular diaphragm.



More cracks can be seen from the backside.



Here's another shot.



The foam turns into some sticky gunk that sticks
to everything. It all has to be scraped off.



Once the outer edge is clean the inner edge is next.



After scraping all the residue off, it looks like this.



Pieces of the old decayed surround.



The cone tweeter surround is also removed but the
chrome ring is saved.



The diaphragm often becomes convex (curved inward) after
the surrounds break down. This has to be fixed since it
needs to be flat when we align the voicecoil. I used
to get the thing damp, then press it as shown and wait
for it to dry. The lamp speeds the process. I don't
do it this way anymore because it sucks. The picture
below shows the latest way with carbon fiber strips.



The carbon fiber strips are placed like a floor joice
to prevent the diaphragm from curling. They work great!



The outer perimeter of the diaphragm is so long that
EACH speaker takes TWO surrounds normally meant
for a 6.5 inch speaker. These surrounds also work
for the Panasonic RX-C100 which was what I initially
bought them for.



You have to do some trimming here and there.



Then make a clean cut here. Do this to 4 surrounds
for a pair of these speakers.



The outer edge of the surround is glued first at
one centimeter intervals. You have to use gel super
glue. You must tug and pull as necessary to get it
to lay right. This is a very difficult thing to do
without ripping the surround.



Here the outer edge is almost complete.



The diaphragm is flat on the table while the
inner surround edge is glued(Elmer's glue).
This step is critical so that the voice coil
is aligned correctly.



Here's one with the outer surround completed.



Here's a completed set with new tweeter surrounds
and chrome rings back in place.



Brett

Well done prime!
Perfect shots of an perfect work!

Very good documentation and very interesting speaker chassis concept.

Congratulation for your perfect fixing job!

How does the suspension of the tweeter works?
I have no idea ?!?!

Prime --thanks alot for this brilliant presentation-- and for all the effort to make this post--

its a rare and valuable treat to see something thats new and very different to us --

thats alot of creative work --to experiment and to finally accomplish this.

i know exactly how good the results do sound-

like awesome !!!

That's some brilliant improvising right there. Impressive stuff, and very helpful for other non-standard shape/design speaker restoration.

Thanks a lot for sharing!



Rock On.

posted by djyetix:

quote:

How does the suspension of the tweeter works?

It is a whizzer tweeter driven by the woofer voice coil.
The outer edge of the tweeter is isolated from the main
backplane via a 4 inch(10 cm) surround. The tweeter moves
in cadence with the main diaphragm for low frequencies.
At the other end of the spectrum, the tweeter projects the
highs directly from the woofer voice coil without getting
dampened by the mass of the main diaphragm.



The whizzer tweeter uses a 4 inch(10 cm) surround.


The chrome ring is glued on top of the new surround just as it was originally.

Great speaker restoration, Prime!

Excellent work!! I hope Freddie see this. Hey, were you going to paint the flat woofer also to cover the stains?

Nice work!!!!! I sold one of theis units a while back because of the woofers also. I can't remember who i sold it to though. Before the woofers went though, i have to agree, this box was outstanding!!!

posted by erniejade:

quote:

I sold one of theis units a while back because of the woofers also. I can't remember who i sold it to though.

Brian,
It was a CK-3 and you sold it to me!

posted by Fatdog:

quote:

Hey, were you going to paint the flat woofer also to cover the stains?

Cotton swabs and bleach will remove the stains.
With the grills in place the stains are not
really that visible. I do it if its really bad.

BTW, Fatdog, the tweeters at the end were airbrushed white
due to heavy browning that I couldn't remove. I haven't
painted any of the woofer portions so far but I might.
Its not a bad idea.

thats kick ass work man ,i know thats about the hardest set of woofers there is to re foam and very time consuming but you did great work i guess now every other woofer looks easy compared to those.

HOOOO YAAAAA ck3~!!!!! close soo close. HEY did you ever get that the speakers working on that one either? i sware, after 40 the memory just goes down hill fast.

oops - my post above forgot to mention ---

that Prime made this difficult repair to both of my pioneer speakers --
and they sound TREMENDOUS !!

and ----wouldnt ya know -
-there is yet another 'adventure' story -- surrounding these surrounds

so -- stay tuned -
later

quote:

Originally posted by Prime:
A year or two ago I was searching Ebay for boomboxes and
came across a box that caught my eye. It was another
component box that had large bass vents on the back of the
speakers. The speakers themselves were a little unusual
because they were flat and square. It was the Pioneer CK-5.
I ended up winning it for a song. It was a nice warm day
when it arrived so I unpacked it and carried it to the
picnic table in the backyard. I ran a cord over, plugged it in
and tuned to some hip hop station.

I cranked it up a bit and was stunned by the bass output!

It was literally vibrating the whole picnic table. This
box was delivering bass on a Telefunken Studio 1 level
yet it was just half the size of a JVC PC55.

After about one minute of loud volume the bass was lost and
the speakers began rattling violently! The surrounds had failed.
The surrounds were initially intact but after my short but
loud test drive they crumbled and that was the end... for now.

Getting replacement surrounds for these speakers is not
possible. So after allot of thought and some trials and
errors, I made my own square surrounds. The process is
quite time consuming and tedious but the end result is
well worth it.

Here's a brief step by step illustration of the refoam process.
Notice the rotted surround around the white rectangular diaphragm.
More cracks can be seen from the backside.


The foam turns into some sticky gunk that sticks
to everything. It all has to be scraped off.


The cone tweeter surround is also removed but the
chrome ring is saved.

The diaphragm often becomes convex (curved inward) after
the surrounds break down. This has to be fixed since it
needs to be flat when we align the voicecoil. I used
to get the thing damp, then press it as shown and wait
for it to dry. The lamp speeds the process. I don't
do it this way anymore because it sucks. The picture
below shows the latest way with carbon fiber strips.
The carbon fiber strips are placed like a floor joice
to prevent the diaphragm from curling. They work great!
The outer perimeter of the diaphragm is so long that
EACH speaker takes TWO surrounds normally meant
for a 6.5 inch speaker. These surrounds also work
for the Panasonic RX-C100 which was what I initially
bought them for.
You have to do some trimming here and there.
Then make a clean cut here. Do this to 4 surrounds
for a pair of these speakers.
The outer edge of the surround is glued first at
one centimeter intervals. You have to use gel super
glue. You must tug and pull as necessary to get it
to lay right. This is a very difficult thing to do
without ripping the surround.
Here the outer edge is almost complete.
The diaphragm is flat on the table while the
inner surround edge is glued(Elmer's glue).
This step is critical so that the voice coil
is aligned correctly.
Here's one with the outer surround completed.

Here's a completed set with new tweeter surrounds
and chrome rings back in place.

Brett

wow nice detailed work
I recently got ck3 .. forget that
How well do it sound compared to the original
do you think , according to your ears's ?

quote:

Originally posted by Fatdog:
Excellent work!! I hope Freddie see this.

Freddie has seen, and heard, and posted! And let's just say those who had a part know who they are.

It Took Over A Year...My Pioneer CK-5F is FINALLY whole!!!

quote:

Originally posted by Prime:
The bass is incredible though. Deeper and tighter than Studio 1.

My CK-5F:


Gotta agree here. The only, and I mean only time I would give the 'Funken an advantage is if you sat it smack dab in open space outdoors because of the large opening in the back of the Pioneer's speaker enclosures.

BUT...If you sit it as most of us do on a table or shelf, or perhaps a corner, or on the stove , it thumps hard.

Keep in mind if you don't know, the speakers surface area is equivalent to an 8.75" cone speaker.

ok ----its 'story time' (again)

once upon a time --
i thought 3 piece boxes were only for dorks and commies

but brett (Prime) was known back then --
as a respectable type member --

he had a ck5 --
and convinced me to at least TRY for some cheapo ck5 that was listed on ebay -- close-by in florida --

he warned me that the listing photos were not clear --and it was likely that both speakers were shot --

and further advised that few, if any speaker shops could fix these types --

after i won the little sucker - for the short $$ -
sure enough --2 bad speakers --

----so i still had no idea what this box could really sound like --

brett offered to fix them for me --but said it was sort of a 'project' and it may take a long while --

so -- i told him -- that i was lucky to have a famous speaker shop just 30 miles away -- so i did not have to pay for the round trip freight--
or wait a long time --
or take advantage of his kind offer --

next day - i bring them to the shop -- the younger tech guy at the desk -- seemed a bit confused by these odd-balls --

but with great confidence --
reminded me that his boss 'old louie' had fixed EVERY speaker ever brought in there for 35 straight years !!
"NO PROBLEM "..........


well - i knew louie pretty well --
so i left the ck5 speaker for him --with a note :

" louie -- these speakers are strange -- so please dont bust your butt on them --
i do have a friend in the mid-west who has offered to fix them -- on the small chance that you cant "

a few days later -- there is this message on my ans. machine ::

"..............if you have any friend in any state that has a clue at how to repair these friggen things -- feel lucky "

____________________________

there is a good chance that those pix in this thread are MY speakers !!!

SO -- THANKS, brett for the big job on fixing these for me --and more thanks for getting me into this awesome pioneer CK series --

quote:

Originally posted by redbenjoe:
there is a good chance that those pix in this thread are MY speakers !!!

SO -- THANKS, brett for the big job on fixing these for me --and more thanks for getting me into this awesome pioneer CK series --

I agree Ira 100%! But those carbon fiber strips look awfully familiar to me!

The pictures I used above are a compilation of of several sets I've done.
The carbon strip picture is a shot of Freddie's speaker while the two
completed units at the bottom of the post are Ira's set.

I'm glad you guys like them! They sure are some hard thumpers!

Brett

Superb work man far to compicated for me to attempt.

tim --if you did learn his procedure --you could become the 'old louie' of the UK !!

quote:

Originally posted by redbenjoe:
tim --if you did learn his procedure --you could become the 'old louie' of the UK !!

Ok im in ira send me an sk to practise on .

oldy has first dibs on your work

Dude that is some seriously good work!!