electronics experts: speakers/capacitor question

Factual Questions
1

Hope somebody can answer this for me.

Today I decided to resurrect my old speakers that were just lying around. After a lot of snipping wires, etc. I’ve got them working.

Speaker specifications: Kenwood LS-28, 2 Way 2 Speaker System, Maximum Input Power 60W, Impedance 6ohms.

Now, when I opened up the speakers in order to replace the old wiring with new wiring, I noticed a capacitor looking thing (nice big looking capacitor. It’s connected between one wire going to the bigger cone and one wire going to the smaller cone). This capacitor looking thing was glued to the back of the speaker (the big cone thing inside) with what seemed to be black hard glue. Now the thing is, I’m not sure if this is some kinda glue or whether the capacitor looking thing has leaked and that’s the black thing that normally leaks outta these things. The reason why I’m not sure that this is the black stuff that oozes outta these capacitor things is that it is glued the same way in both speakers (i.e. the side of the capacitor that is adjacent to the back of the speaker is glued to the back of the speaker with this black hard glue, while the rest of the capacitor is pretty well sealed with seemingly no leakage anywhere else).

So, my question(s) is/are:

Is this black hard glue looking thing some kind of leakage or is it actually some glue.

If it’s glue, is this normal ?

If it’s leakage, what causes this leakage ? And if I continue to use the speakers as is will it affect the life of the speaker or in any other way cause it damage ? What kind of damage ?

The speakers are connected to an Akai amplifier. The speakers are working quite well, they sound pretty clear and there’s only a very slight cracking sound in one of the speakers (even at low volumes).

2

It’s pretty normal to glue down crossover parts so as to prevent the development of interference between the elements. I highly doubt it’s leakage.

3

I think that this will be a glue that does not ever dry out hard, so that it does not get brittle and break away due to vibration.

4

I think its glue, as I doubt the capacitor juice would dry in this fashion. Also, if the capacitors were failing, the tops (with the X scored in them) would probably be swollen or broken open.

5

You can use almost any kind of epoxy resin glue. Craft-style hot glue works well. Crossover parts need to be glued down to prevent them from vibrating inside the speaker.

6

Hey, Thanks guys. You rock. Everytime. I just found it hard to believe that that was some sort of glue. Looked pretty strange for glue, but the capacitor seemed in rather good shape for a leakage.

Bonus questions:

  1. What’s a “2 Way” speaker system ? What’s 2 Way about a speaker ?

  2. How does the thickness of the audio wire affect output ? I’ve used some pretty cheap audio wires for now… one was thinner than the other, so one speaker was sounding better (the thicker one). So i doubled the thin wire on the other speaker and now this speaker was sounding better than the other. Finally I split the thicker wire and used it with both speakers, so now they’re sounding about the same. Is too thick as bad as too thin ? Is there an optimum wire radius for the speakers with the given specs. ?

  3. What wire do you suggest I use ? I mean, beyond asking for “I need audio wires” what else should I ask the store ? I’m not in the U.S. so I don’t have any Radio Shack around here.

Thanks.

7

A two way speaker is one that has two drivers (what you call the cones). The larger driver is called a woofer, and carries only low frequencies, or in small floor or bookshelf speakers will be fed the entire signal. The smaller driver is called a tweeter, and carries only the high frequencies.

A capacitor passes high frequencies but blocks low frequencies. So in a small speaker system the incoming signal will generally be fed directly to the woofer, and then the cap will be in series with the tweeter to block the low frequencies.

Generally, speaker wire can’t be too thick, but it can be too thin. There is the possibility of getting wire so thick it has unusually high capacitance, but you’re not going to run into that in normal situations.

For short runs (up to 15 feet) and lower power speakers, even 20 gauge is usually enough. So if you stick with 16 gauge, you can run even big speakers for 50 feet with no problem.

So go to any home remodeling center and get some 16 gauge multi-strand lamp cord. This will sound as good as the most expensive wire available in all but the most demanding situations (very long runs, extremely high power, etc.). If you want to step up a little, spend $25 and get something like Monster cable. It sounds the same, but is prettier and may be a bit more flexible, which makes it nice to work with.

Don’t waste money on higher priced wire unless you really like the look or impressing your friends with how much you spent. At best they sound just the same as the lamp cord, and at worst they actually can degrade the sound.

Ugly

8

A two-way speaker is sometimes called a dual-element speaker. It is a midrange cone that has a tweeter mounted in the middle like this. See that funny looking thing in the middle? That’s the tweeter. The blue part is the midrange element. This particular unit is a 6.5 inch cone and boasts a response of 28Hz to 28KHz.
Two-way speakers are good to work with because they require a much simpler crossover design, or sometimes none at all if your bass is going to be blocked from the entire speaker enclosure and fed to an outboard subwoofer.

Since a two-way speaker essentially combines a midrange & a tweeter, it has a flatter response over a wider range of frequencies. The disadvantage is less flexibility in designing your overall speaker system.

9

Is that logical? I am not convinced by the audiophile claims about speaker wire either, but if as you say they can degrade the sound, isn’t that just saying that the cable does make a difference? If that is so then why not an improvement?

10

RJKUgly is correct. Lamp cord “sounds” just as good as $100/ft. speaker cable, since neither contributes significant amounts of distortion. For my speakers, I use 16 AWG wire I purchased for less than $0.10/ft.

We’re getting into GD territory here, but I believe the consensus among reasonable audiophiles is that, if you have extra money to blow, buy better speakers.

11

That was not my point. RJKUgly said that expensive cable would make no difference *or degrade it *. Either it makes no difference or it does. If it does (which we agree is doubtful) then why not for the better.

12

Because the cheap cable is as good as it gets, and if there was any difference (unlikely) it’d be a degrade.
I’ve spoken to a real (ex)audiophile and he use to use ultra-pure ultra-thick wire that cost like $500/m. He also has these real big speakers that are something like 1000W power in and pump out 60W max audio. Now thats efficency.

13

The reason is that most high end cables are just very nice cables, and despite their real (or imagined) differences in materials or topology they make no real difference to the sound. A few, however, employ passive (I think they’re all passive) circuitry in what seem to be filters of one type or another.

In any situation, a filter will alter the signal being fed to the speakers. This is distortion, no matter what you call it.

In some very specific circumstances, I suppose it is possible that the particular distortion added to the signal by a fixed filter box could tend to offset a distortion inherent in the speaker. For instance, if the speaker had a frequency response that rolled off the high end, and the filter box on the cable rolled off the low end to a similar degree, this could be an improvement.

But this same gain can be had using careful equalizing, and can be tailored to your speakers, and more importantly to your room. A fixed filter box may be right one time in a hundred, but will be wrong in the other ninety-nine situations.

So while it was probably a little overkill to say cables never improve the sound and may degrade it, it is the “practical” truth. The cables that contain filter boxes can introduce changes, and those changes are far more likely to degrade the overall sound than improve it.

Although it also certain that some people like that changed sound. This is a matter of taste, and everyone is welcome to their own. But ninety-nine times out of a hundred, the output from the speakers has more distortion than without those changes, like it or not.

So you can waste money trying to find a cable that just happens to fit your situation and which may introduce other problems, or you can put in good clean normal cable and do your signal equalization with a component that was meant for it, an equalizer.

Ugly

14

RJKUgly is right on the money again.

For a typical system, I would estimate that about 96% of the distortion comes from the speakers, 2% from the amplifier, 1% from the preamp, and 1% from the signal source hardware. The distortion introduced by the speaker cables is so low that it doesn’t even figure in.

15

In terms of wiring, the only thing I’d add is that you should try to use the same kind of wire and the same length of wires with both speakers. Though even if you didn’t I don’t think the differences would be that noticeable.