Rebuilding an old pair of Sony 3-way speakers

Speculant

Speculant

Audioholic
Not sure what the model number of these speakers is. I'll provide as much info as I can. The drivers all seem to work, but they are very old and most likely outdated by today's standards. The cabinets themselves are in pretty bad shape, I will strip them down and re-stain them with a ebony stain and re-varnish them. I am not sure what to use as a grill replacement, though, but I know I will want to use magnets to easily remove the front. I was thinking a white color to contrast the black cabinet, and I want something metal that is very transparent.

Prepare for information overload :p

The cabinets themselves are 19 11/16" tall, 11 7/16" wide, and 10 1/4" deep. Those are outside measurements, and the wood is 1/2" thick. There is also some padding around the sides in the interior, so by my estimations the internal airspace for the 8" driver (the other two drivers are of course sealed) would be best rounded to 1.2 cubic feet.

All the drivers are 8 ohms.

The 8" subwoofer has "I-502-223-II", "94-SDS" written on it and it is 4W.
The 4" midrange has "I-502-221-II", "93-SDS" written on it and is 2W.
The 2" tweeter has "222-11" written on it and is 10W.

The center of the subwoofer is 6" high from the bottom of the cabinet, and centered.
The center of the midrange is 7" above the subwoofer, and it is offset to the left of center by 2".
The center of the tweeter is 2 1/2" above the midrange and offset to the right of center by 1 1/2"

The port is 2 1/4" wide and 8" long.

The crossover is very, very basic. It consists of a 2uF cap filtering the 4" midrange and a 1uF cap filtering the tweeter. The subwoofer is not filtered at all, and thus runs fullrange.

Whew! Did you get all that :D

When I rebuild these cabinets, keep in mind that I don't want to spend a lot of money, but I do want to improve the sound quality as much as I can.

I was thinking this shopping list:

Crossover 3-Way 8 Ohm 800/5,000 Hz 100W 260-210
Dayton Audio DC200-8 8" Classic Woofer 295-310
JAMO 20470 4-1/2" Sealed Back Midrange 299-952 (I think it will fit, both drivers have the same diagonal measurement.)
JAMO 20132 2" Paper Cone Tweeter 299-965

I am a little worried about the tweeter fitting, the holes are the exact same distance apart but as you can see in the photos the old tweeter only has two mounting holes and the new tweeter has four, so the bottom hole of the new tweeter will hit the wood block that the port is mounted on. I'm not sure how to fix this, would it be possible to bend one corner of the tweeter up so it fits?

I would greatly appreciate any suggestions to my list.
 
Swerd

Swerd

Audioholic Warlord
When I rebuild these cabinets, keep in mind that I don't want to spend a lot of money, but I do want to improve the sound quality as much as I can.
My first reaction to your post was to put my palm to my face, and think "here's another guy who has a Parts Express catalog, an idea, and a circle saw". In your case, instead of a saw, you have a beat up old cabinet, and you want to keep the cabinet and scrap its drivers and crossover.

The short answer is no this plan will not work and you'll be unhappy with the results.

I searched some old posts for answers to questions similar to yours. Read this.
 
Speculant

Speculant

Audioholic
Exactly the response I expected, looks like I'm on my own on this one.
 
Swerd

Swerd

Audioholic Warlord
Exactly the response I expected, looks like I'm on my own on this one.
I'll ignore that jab and offer more straight-forward advice. The conclusions will be the same.

You propose starting with an existing cabinet and want to replace the 8" woofer with another. Look up the Thiele/Small parameters (Qts, Fs, and Vas) of that woofer, and use an online calculator to estimate the cabinet volume for that woofer, and whether it would work better in a ported or sealed cabinet. If you are lucky, it might fit the cabinet you have, but not likely. The standard way to do all that is to first select a woofer and figure out what volume and type of cabinet works best for it.

Moving on, you propose to use an off-the-shelf crossover to cross over that 8" woofer to a midrange driver at 800 Hz. Look at the woofer's frequency response curve provided by the manufacturer. That 8" woofer is already going into breakup at 800-900 Hz, something you will hear as harsh sounding noise. As a quick guess, that woofer should be crossed over no higher than 500 Hz, and probably would be better off at 400 Hz, a whole octave lower than the onset of break-up noise.

I would go on, but the midrange and tweeter you linked have no frequency response information at all, so no one could guess whether the 5,000 Hz crossover frequency you proposed might work or is an impossible dream.

All I've done so far is to walk you through a simple process for deciding if such a combination might work. So far the answer is no. The design process for making something that actually does work is more involved, especially for a 3-way.
 
Speculant

Speculant

Audioholic
Thank you for going into a more detailed explanation.
 
T

templemaners

Senior Audioholic
Swerd is 100% right on this one. Instead of wasting your time on parts that have a very low probability of working together (let alone working well together), you'd be better served looking on PE or Madisound for a low priced speaker kit, like this TriTrix MTM.
 
Speculant

Speculant

Audioholic
You guys are beyond serious with that TriTrix kit, the person who came up with it must be a genius.
 
Swerd

Swerd

Audioholic Warlord
You guys are beyond serious with that TriTrix kit, the person who came up with it must be a genius.
The TriTrix is a great design. But the price, while actually very low, is still a lot more than the cost of the 3 drivers you mentioned earlier. If that is all you can spend, then it's too much.

To design a 3-way that could work, you would have to measure the frequency and impedance response curves of each driver while actually mounted in the cabinet. You would need test gear and software, and have some experience in using them. Compared to all that, the $259 for the TriTrix kit is a bargain.
 
GranteedEV

GranteedEV

Audioholic Ninja
Exactly the response I expected, looks like I'm on my own on this one.
:rolleyes:

I get that you want to save money, but your path isn't likely to get you results that are even a quarter decent.

If you want to try out buyout drivers, maybe look into this:

http://gonecatfishin.net/Hakumya.pdf or some of the other stuff on that site.

The problem with parts express crossovers is that they're going to be WRONG. Speakers aren't flat impedance, so crossovers designed for flat impedance automatically can't work with drivers that don't have it. You end up with mismatch slopes, maybe even no slope at all. That's poor driver integration and even worse response (how does that parts express crossover account for differences in driver sensitivity? driver offsets? break up? baffle step?). Why not do it right? If you can't afford to shell out for DIY then just buy a commercial speaker for the same money - it'll sound better.

If you want to DIY you have to understand that there's more to a speaker than a 2 dimensional concept of capacitors and inductors.

If you really want it to be your individual design, then here's what I recommend

1) something to measure the drivers (Smith and Larson WT2 or Dayton WT3)
2) microphone (Dayton EMM-6) + Phantom Power (M-Audio MobilePre) for response measurements
3) A crossover (Behringer DCX or MiniDSP) + separate amp channel (dayton 50w) for each individual driver. So for a 3 way that's six amp channels.

If you're willing to invest in the above then the sky's the limit. #3 isn't completely necessary as you can learn to do passive speaker, but it's highly recommended because your knowledge of driver / component interaction isn't factoring in the 3rd dimension of how it works.

That way at least you can skip the mess. But the above will cost you more than the stuff you're looking at. Which is why DIY ain't cheap if you don't build someone else's design.
 
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Speculant

Speculant

Audioholic
I guess the dream when I joined these forums was that I would be able to take advantage of less expensive drivers and still have acceptable sq, with the right crossover components and the correct cabinet construction. I have now found that there is no way to do this, as less expensive drivers require more equalization, which requires more expensive crossover parts, and the only other option is expensive driver.

I bet I could get drivers that were inexpensive to work with these cabinets, but you are right when you say that I would need to buy expensive listening devices and sound measurement software. Plus I would need specific crossover components which in themselves are not inexpensive.
 
GranteedEV

GranteedEV

Audioholic Ninja
You can check out the link I gave you for a design using cheapo drivers.
 
Speculant

Speculant

Audioholic
Let me fill you in on my current sound system: two 10 year old boombox detachable "bookshelf" speakers with 5 1/4" drivers and tweeters I'm not even sure work running full range coupled with a 10" $15 subwoofer crossed over at 100Hz. To top it all off, a 5+ year old 25w per channel kicker car amp powers all of this. And you know what? This system, in all it's pieced-together glory, still sounds miles ahead of various college buddies big-box "2.1" systems with tinny-sounding 3"-4" fullrange drivers and a well past overpowering sub. My system also sounds much better in contrast to the systems of some other people on my floor that only seem to consist of separate 12" car subs (pure spl that can be heard four floors up).

I feel that spending even $100 on something like this would be a massive improvement on my current setup, so I think that's what I'm going to do.

What GranteedEV said about getting measuring tools and a few miniDSPs is really what I want to do, but with my current status as a struggling college student that's not really something I have the space or money to do.
 
M

maxb070

Audiophyte
hey i have the same pair of speakers was wondering if you learned anything about the model of speaker, thanks
 

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