AVS Forum banner
1 - 18 of 18 Posts

·
Registered
Joined
·
701 Posts
Discussion Starter · #1 ·
First and foremost, I'm well aware that this is not on the caliber of most systems here, but this is just my bedroom stereo and it sounds good as it is, but not nearly perfect. What I'm using is an old(20+ years old) Sony system with the speakers that came with it. Got them from my grandmother when she moved in with my aunt and I've loved how clean and precise the system sounds since I can remember. The system was very rarely used and is in perfect shape.


The only major drawback to the system is that despite having three independent cones in the floor standing speakers, it uses a single input and does not have an internal crossover. I have not cut it open to verify how it's wired, but I can hear that all three speakers, a 1.5" tweeter, ~3" mid and 8" sub are all attempting to output the same frequencies and it's causing a notable dulling to the mids.


Source is typically a computer I have near by, that was running a stock Emu-1212m, till the 0202 daughter card died so I broke out a few year old CD player that has always been the best sounding component I own, I just don't like having to deal with disks constantly, and it's only made the problem more noticeable. I'll be upgrading to an external USB dac like the fubarII and I know that's not going to help, so I want to buy/build a passive crossover to add to the back of or inside the tower to help filter frequencies to the speakers best suited to output those frequencies, and hopefully help sharpen up the mids.


I can read a diagram with ease and can solder well to very well, so I wouldn't be against building one if that's really be best budget option. The real kicker here is that the WAF is non-existant so I have to do this on a very limited budget. Any advice?


Thanks,

AD
 

·
Registered
Joined
·
701 Posts
Discussion Starter · #2 ·
It's a long read, I know, sorry guys. I've found some Infinity CS3006 or 3007 internal 3-way crossovers with option for bi-amping later on e-bay and for quite cheap, anyone have any experience with these?


I do have several 8" and 10" powered subwoofers around that have built in low-pass filters that are adjustable from 100hz to 450hz(if I remember right) that I could add in between the amp and speakers and just dis-able the internal 8" subs, but I would really then like a two way filter for the mid and the tweet, though I don't really like the idea of a double filter, it would work, would it not?
 

·
Registered
Joined
·
6,908 Posts

Quote:
Originally Posted by ArtosDracon /forum/post/18181293


despite having three independent cones in the floor standing speakers, it uses a single input and does not have an internal crossover.

Having worked as a teenager in a Sony service depot, I can assure you that there is a network in your Sony three-way speaker system, however basic it might be.


It is certainly possible, but unlikely, that the capacitors have shorted/deteriorated so that they are no longer performing they intended purpose; there will be no damage to any of the inductors.


That said, you should disassemble one of the boxes and diagram the wiring you find, noting the component values printed on the network parts, before you even consider a "new" crossover system.


As it stands, you have no information on driver impedances or performance characteristics.


You can then simply replace those parts or use the information to determine the characteristics of the network.


Do you have model numbers for the speakers???
 

·
Registered
Joined
·
628 Posts
There is at least a cap on the tweeter to filter out the lows. There is no way a tweeter can handle a full-range signal at any appreciable volume without frying.


It is possible that they relied on the natural rolloff of the other drivers when designing the speaker. A crossover may help to some degree, but the only way you are going to get a useful crossover in there is to measure the impedance curves and frequency response of each driver while in the enclosure and design a crossover network with that data.
 

·
Registered
Joined
·
701 Posts
Discussion Starter · #5 ·
The speakers are SS-U211s, I suppose it could just be because it's an open cabinet inside and I'm hearing the other drivers.


I'm glad to hear there is a network of some sort inside, I do suppose it's better than nothing.


I've dropped a Xonar DS into the system for now, I'm underwhelmed compared to my EMu-1212m, but happy enough to see how it goes for a few days before I actually order a new DAC for it. It definitely has a warmer sound to it than the 1212m did, but it doesn't soudn quite as precise either.
 

·
Registered
Joined
·
6,908 Posts

Quote:
Originally Posted by ArtosDracon /forum/post/18185291


The speakers are SS-U211

A quick search showed they are 8-ohms and handle 200W but not much else.


I will bet you dollars to donuts that there is nothing wrong with them!!
 

·
Registered
Joined
·
1,693 Posts

Quote:
Originally Posted by ArtosDracon /forum/post/18181443


It's a long read, I know, sorry guys. I've found some Infinity CS3006 or 3007 internal 3-way crossovers with option for bi-amping later on e-bay and for quite cheap, anyone have any experience with these? ...

No. Crossovers are like gloves in the bar in Star Wars; they only fit the drivers they're designed to fit.


To do it right, you need data - frequency response and impedence response curves from the drivers - and XO design software. The latter is available as freeware, but without driver data, it's useless. All told, figure about $200-300 in tools before you can even order components, unless you know someone, and you'll know just how bad or good the result should be. It's a great hobby, but you gotta wanna.


What others have suggested is probably your best choice. Pull one apart and find all the components, including wires and those that look like part of the speaker. Replace everything but the drivers; wire's cheap. Parts Express is one good source for components; you can ask about this on their forum, too.


HAve fun,

Frank


PS a 1" layer of accoustic foam works wonders on those internal resonances and reflections, even in ported alignments.
 

·
Registered
Joined
·
701 Posts
Discussion Starter · #8 ·
Thanks for the info guys, crossovers are off the list, I'm still probably going to crack them open and re-wire and inspecc the networks in them, make sure everything is as it should be. I just finished building new RG59 RCA cables for the CD player and a 1/8" stereo to dual RCA for the output from the PC to the amp and it sounds pretty darn good.


That 1" acoustic foam to the interior is a highly likely upgrade to help isolate the dirivers, THANKS ALL.
 

·
Registered
Joined
·
701 Posts
Discussion Starter · #9 ·
Got around to trying to open them up today and I can't get them open, lol. The grills seem to be glued on and with enough force to separate them, the edges of the grill and the cabinet get damaged, any ideas? I can see through the small hole where the wires pass that the rear panel is glued on with a thick, milky yellow wood glue, but I'd be much more apt to breaking that rear panel and just making another than damaging the cabinet any more. Is it likely that the drivers could be rear mounted to a pre-assembled cabinet and face, wired and then the rear sealed?


I guess I'm just used to cheaper or more modern speakers with removable grills.
 

·
Registered
Joined
·
7 Posts
I came across this thread while searching for info to help me rebuild some old Kenwood speakers so I thought I'd chime in since I just found some info on some old Sony's from 1991 I had at one time.


The ones I had were the Sony SS-511AV 3-ways with a second passive woofer. I just ran across a diagram I drew of their circuitry so here it is if it will help you any. Sorry I didn't record the capacitor values when I drew the diagram years ago. Basically just a simple high-pass filter on the mid and tweeter.


(+) Input to (+) Woofer [8 Ohm]

(-) Input to (-) Woofer


(+) Input to (Capacitor) to (-) Mid [8 Ohm]

(-) Input to (+) Mid


(+) Input to (Capacitor) to (-) Tweeter [Unknown Ohm]

(-) Input to (+)Tweeter


ETA: Mine had removable grills....
 

·
Registered
Joined
·
3 Posts
I'd first like to point out that I am new to this field, and have virtually no experience so forgive me if this is something obvious I've overlooked. That being said, I recently had the passive crossover go out(I think) on an older set of tower speakers, pretty standard 2" tweeter, 3.5" mid, 12" woofer arrangement. Still getting power through the woofer, which has no low pass filter, but the mid and tweeter have no response. My conundrum is that while the circuits to the tweeter and mid are very simple, consisting of a respective capacitor wired in series with a resistor in the positive line of each, there is another component in the positive input before it splits off into the separate lines for these two. I am uncertain of the function of this component, it's in a plastic housing and resembles no modern component I'm familiar with, and can find no info from the markings on it anywhere online thus far. They are: Prowell PA-1.25A

Any help identifying the component and its function would be greatly appreciated...
 

·
Registered
Joined
·
6,908 Posts
How 'bout a picture?
 

·
Registered
Joined
·
3 Posts
Here's a few pics of the component, all I can tell you is that it's a 2 pin component that powers all three speaker circuits, and the resistance is steady at about .3 ohms


 

·
Registered
Joined
·
1,657 Posts

Quote:
Originally Posted by frogonahog /forum/post/21700170


Here's a few pics of the component, all I can tell you is that it's a 2 pin component that powers all three speaker circuits, and the resistance is steady at about .3 ohms

I see a thermal circuit breaker-2 caps and 2 resistors. The 2 caps would probably be 1 for each the mid and high. the resistors are to pad down one or both of those to match the woofer levels.


Since there are no coils-they are relying on the internal inductance to roll off the highs is the lows and mids.


Since the slopes would only be 6dB/octave (first order filters), you will hear a lot of the same thing come out of all the drivers.


You will have to have a lot of luck-or a lot of time in measurements and prediction to even start to "improve" on what is there. It's not worth if-in my opinion.


If you wanted to replace anything-then jsut replace the caps with the same values-in case they have changed over the years. You could do this for a couple of dollars each.
 

·
Registered
Joined
·
3 Posts
thanks, I wasn't aware they used thermal breakers in those old setups, but makes sense to me. main problem I'm having is just that there is literally no power going to the mid and high but I'll try replacing the caps and see what that does for things...
 

·
Registered
Joined
·
78 Posts
Good caps and inductors can cost more than the drivers themselves. If the speakers are old then surrounds are probably rotted. Not worth messing with. I can understand the desire to tweak! I am a hopeless tweaker myself. If you want to build your own speakers go to Parts Express and start from scratch. Then you can play with the crossover to your hearts content!


I personally have modded the crossovers in the Magnepan MMG's with very good results. With that said, I have probably spent over $400 on caps and inductors, but now I have a speaker that performs like a $2K/pair.
 

·
Registered
Joined
·
6,908 Posts
You never have to replace the inductors, only caps deteriorate.

Madisound also has a good selection of caps.
 
1 - 18 of 18 Posts
Top