Modernizing Pioneer CS-G303's

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Cam94z28

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Joined 2004
#1
Hi,
I have decided to toy with the idea of taking an old pair of my speakers, and modernizing them. I have a pair of Pioneer CS-G303 Floor Speakers with the following specs:

6 ohms
crossover points at 3.5khz, and 7khz
12" Woofer
4 3/4" Midrange
2 5/8" Tweeter

dimensions: 15″ × 26.5″ × 12″(WxHxD)
Ported

Rather than throwing these in the garbage I thought I might update all of the drivers with what's available from partsexpress or a similar site. With crossover points that high is it worth pursuing this using the existing crossovers, or am I better off starting from scratch and building my own box(keeping mind I am not a carpenter)?

Any ideas would be appreciated.

Thanks,
-David-
 
#2
You should probably design (and have someone else help you build the box, perhaps) a new enclosure as t/s parameters do change with age--magnets are weaker, surrounds lose their stiffness, etc. Anyway, are the drivers in operable condition, are their surrounds up to par and such? If not then lend them to the garbage can. However, if they are decent then, measure t/s and we'll go from there.
 
#3
All of the drivers are in good condition(Although the woofers are showing their use), I just don't like the sound of these speakers. The woofers don't produce low notes at all, and both the mid and tweet have paper cones.

I was hoping i could use the existing crossovers, and find speakers on partsexpress that would go right into these cabinets.
 
#4
crossover points at 3.5khz(!?), and 7khz
Click to expand...

You'll probably find the "crossover" consists of two capacitors.
And the bass unit has no baffle step compensation,
explaining the weak bass performance.

Building a 3-way is very difficult and cannot be taken lightly,
and I don't know any good cheap 12" 3 way designs.

🙂 sreten.
 
#5
sreten,
What would the part of the crossover involved in the baffle step compensation look like. I do not have them apart now, but I do recall more than just two capacitors in the crossover the last time i had one of the woofers out.
 
#6
Are the drivers alnico? Can you post pictures?

The crossover is the least likely part you can reuse.

I'd suggest a round of modifications -- ductseal, puzzlecoat, better wire, better caps, perhaps some box bracing, streamline the front edges of the box -- before you venture out on a complete driver replacement regime.

dave
 
#7
How do I tell if they're alnico or another type? Sorry, I'm not only a newbie to the DIY scene, but Vintage speakers as well.

I do know that the magnets looked awfully small to support a 12" woofer the last time i had them out. I'll see if i can get some pics to show you.
 
#8
Cam94z28 said:
How do I tell if they're alnico or another type? Sorry, I'm not only a newbie to the DIY scene, but Vintage speakers as well.
Click to expand...

An alnico magnet is smaller than an equivalent ceramic unit.... i've attached a pic of a typical alnico magnet (some look a bit different -- ie soupcan units).

dave
 

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#10
Cam94z28 said:
sreten,
What would the part of the crossover involved in the baffle step compensation look like. I do not have them apart now, but I do recall more than just two capacitors in the crossover the last time i had one of the woofers out.
Click to expand...

I find the first crossover frequency of 3.5KHz highly dubious.

Its straight forward to trace a crossover :

high pass : (applicable to midrange and tweeters)
first order series capacitor,
second order + parallel inductor,
third order + another series capacitor
etc.....
low pass (applicable to bass and midrange)
first order series inductor,
second order + parrallel capacitor,
third order + another series inductor
etc.....

You may also find resistors for level matching.

BSDC is usually illustrated by a much larger series inductor with
the bass unit than you'd expect, possibly with a parrallel resistor.

🙂 sreten.
 
#11
Cam94z28 said:
nope, these are the standard style magnets, they look like the magnets on any modern subwoofer, only they look to only be 10oz or so.
Click to expand...

Sounds like a typical mid-late 70s Japanese, high-Q, smallish box, ported yields big lump in the upper bass design. Try stuffing the port to do a quick experiment to see if you can get better bass....

If trying to recover units like this, i have done the regular tricks to the bass driver, made the enclosure aperiodic, and replaced the mid & tweeter with a small FR like the Tangband W3-871 (loaded into a piece of 4" PVC run front-to-back) with a series XO in the 250-350 Hz range (choosen based on the baffle-step frequency), with yours the initial target would be about 300 Hz.

dave
 
#12
I gave my old Pioneers to my brother, who probably has more use for them than I do. But while we're on the topic of crossovers, can you all give your opinion on the crossover that's in my Wharfedale Opal 90's. I had to fix a passive radiator in one of these(the cone separated from the spider), so i thought i'd take a pic of the crossover while i had it apart. I don't know much about building these, so I can't identify high quality vs low quality components.

An externally hosted image should be here but it was not working when we last tested it.
 
#16
planet10,
I don't think I'll worry about upgrading the caps, atleast until I gain some experience building crossovers, and soldering.

I had it pulled out of the way in the picture, but these cabinets are stuffed with poly fill. I've recently read that lining the inside of the cabinet with carpet felt instead of poly-fill can improve sound. Is this worth trying, or will the sound improve much compared to poly fill stuffing?
 
#18
already upgraded these... well sorta

I have a pair of CS-G303's that I upgraded out of necessity. My friend blew the woofers. I probably should have taken more care than simply replacing the woofers for optimal sound quality but, this is just a crutch until I can replace these aging dinosaures. For just under $120 bucks I got some woofers from:
http://www.speakerworks.net/heavy_duty_woofers.html
I did have to use my dremel tool to enlarge the opening a little bit to get these suckers to fit. I also used some silicone RTV to make sure there was a good seal with the speaker box.

I admit I'm a novice when it comes to this, but they sound much better than I expected. The bass is significantly louder and tighter than the original woofers. The down side is that the lower mids are a little flat. I have to adjust the eq to lower the bass and treble to get them to sound right.
This would be a good quick if you're looking for a loud party speaker (that's what they were being used for when they were blown).

If anyone has any suggestions as to how to improve upon what I have already done(I'd probably lean toward replacing the crossover) let me know!
FYI I'm a complete NB when it comes to speakers, however I am very knowlegable with basic circuits so I will understand when you talk about Henrys, Farads, and Ohms.
 
#19
Measure the response of the loudspeaker as a whole, then disconnect the tweeter and measure just the woofer and finally disconnect the woofer and reconnect the tweeter and measure the tweeter.

From there, we'd be able to see where you are at as of now and can guess the approxiamate Qtc of the enclosure.

If you don't have some way of measuring SPL (RS SPL meter) then can you please provide us with internal dimensions of the enclosure (Volume of Box)?

Also, we'd need you to measure the Thiele Small Parameters of the woofer that you're using, you'll need a resistor of sufficient power rating and about 8ohm resistance. You'll also need a DMM.

Alright, tell us the options! Oh, preferrably you can do both types of measurements, but I'm thinking the Qtc is too high (box is too small) and that is causing a bump in the passband of the woofer--therefore muddying up the midbass.
 
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