Pioneer Rectangle Speaker owners

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Superduper

Moderator
Staff member
Because I've never personally seen a pair with original intact foam surrounds, wondering how many of you folks out there own one of those rectangular Pioneer CS series speakers, and whether the foam surrounds are still holding? Guess I'm trying to get a feel of the ratio of failed surrounds on these speakers vs. surviving orig surrounds.

Also, 1. IF you have surviving orig surrounds and 2. IF you have owned them for a significant part of their existence, please indicate the type of weather/climate you live.
 

Lasonic TRC-920

Moderator
I have oftened wondered why the square speakers seem to have a higher fail rate in the surrounds?????

Wouldn't they be made from the same materials?
 

Superduper

Moderator
Staff member
No. Most boombox speakers seem to have an integral paper surround that is treated with a gummy substance whereas the pioneers used true foam surrounds. Aiwas used foam in some of their higher end boxes as did many car stereo speakers of that era and most have probably deteriorated by now. Even the M90 used a formed (accordian shaped) style paper surround that was nothing more than a continuation of the cone material.
 

Fatdog

Well-Known Member
Staff member
I have some Boston Acoustics HD5 speakers from back in the early '90s and the foam is questionable. If you push on the foam it does not return to its shape, but it also does not disintegrate either. But yeah... it won't be long. I guess it just sort of happens with foam. :thumbsdown:
 

redbenjoe

I Am Legend
i have a small pair or those --bot the big set with the wonderful ribbon tweets-

got them off ebay -- the surrounds were both shot

send them to member prime in michigan -
he fixed them with factory spec materials --extreme tight deeeeeeeeeeeeeeeeeeeeee
eeeeeeeeeeeeeeep bass -
they have held up for this past 5-6 years

the ' surrounds ' are not ' around ' the speaker -
instead they ARE the speaker
 

Beosystem10

Member (SA)
Strangely enough, my Technics SAC05L has its original foam suspension in place and I've owned it since new, almost 32 years ago. I had the speakers apart to clean them not that long ago and checked, but sure & they're fine, as are the foam surrounds in the speakers I have that came from a Sansui CP5 which are now the woofers in my Hitachi TRK-3D40. Yet the recently purchased box in my avatar image had clearly been better looked after than any of these other things, is otherwise pristine yet had foam rot so bad that there was virtually nothing left of the rings, they'd just vanished like my socks do from the washing machine but unlike the socks, that foam wasn't coming back without my buying new parts. So some boxes are clearly less prone than others to this phenomenon but why? How? which ones are the worst? Howcomes the Technics remains foam rot-free but the Panasonics which use the same woofers are almost always in dire need of the foam job?

And here's a thought: Would it not be easier and safer to use square kits to do these Pioneer foam repairs? That way, they could be glued in without the need for a cyano-acrylate adhesive as they'd be under far less stress when drying off. OK, so the square repair kits were a few Quid more than the round ones but I'd certainly not hold back on the spending if it means that a rare and special machine like that Pioneer gets to live on.
Maybe the likes of QSR, who supplied my foam kits, would consider doing the foam by length from a roll and making separate corner pieces in various radii for bespoke jobs such as that lovely Pioneer. I want one.
:drool:
 

Cpl-Chronic

Member (SA)
4 factors affect foam surrounds...

sunlight, moisture, temperature & habitual usage.......The well taken care of radio with the rotted surrounds may have been a fav, maybe? If the previous user got some use out of it, it could face hot beaches & cool nights at the cottage, etc. Lots of sun & moisture to add to its aging process where the dirty radios & the Technics sat indoors, hibernating away from the elements in a controlled climate, for the most part....Of course, even if surrounds look & feel the same, they have different compositions that affect longevity too...

That's my guess.....

Cpl
 

Reli

Boomus Fidelis
I'm talking out my ass here, but I think paper surrounds are superior for rock and classical music.....they're more rigid and therefore provide more accurate reproduction of certain instruments. Foam and rubber surrounds are more mobile, so they push more air, starting at lower volume levels. So they sound warmer, but not as precise. Great for 808 bass, but not for guitar.

If you go to Best Buy or Walmart, you'll notice that every modern "shelf system" uses foam or rubber, because they want to give the consumer as much bass as possible......Considering the type of music people listen to nowadays.......But they can't be heard for blocks like an M70 or M90, because they suck at producing midrange frequencies.
 

Lasonic TRC-920

Moderator
Reli said:
I'm talking out my ass here, but I think paper surrounds are superior for rock and classical music.....they're more rigid and therefore provide more accurate reproduction of certain instruments. Foam and rubber surrounds are more mobile, so they push more air, starting at lower volume levels. So they sound warmer, but not as precise. Great for 808 bass, but not for guitar.

If you go to Best Buy, you'll notice that every modern "shelf system" uses foam or rubber, because they want to give the consumer as much bass as possible........But they can't be heard for blocks like an M70 or M90, because they suck at producing midrange frequencies.
I would have to agree with you on that. I don't know if there is any science behind it, but I think foam and rubber provide a great xMax to create bigger bass
 

Fatdog

Well-Known Member
Staff member

Beosystem10

Member (SA)
That's what I meant about using square foam to do the job. Glad it's already been done and that I wasn't having crazy thoughts! ;-)

Interesting how, in the thread, the restorer cut off the dust caps and used the technique involving paper shims to keep the voice coils centred. Queensland Speaker Repairs, suppliers of my re-foaming kit, mention that way of doing the job in their instruction leaflet but when I did the PC-5 recently, I just couldn't bring myself to cut the caps out so I did it the other way, by simply making sure at every step that the coils were centred.

The way it's done on the Pioneer in the thread that Bobby posted the link to is a joy to see, a truly professional job, inspiring and makes me want that Pioneer even more, especially since I've read only great reviews about how good these boxes sound.
:drool:
 
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