Optimus 990 speakers

[Mongojustpawn]

I found a pair of these at the thrift store today, $5/pr, the reviews on AK were that they're are very low end, but I've already bought them, thoughts, opinions.

[Sir Thrift-a-Lot]

I had a pair of those years ago.   I put handles on them and used them for PA.   If the veneer is reasonably good, they are decent looking speakers and could be fun to experiment with.   Have you listened?   What are your impressions?

[SunnyDaze]

Eh, they're definitely nothing great. Built to a budget and that's about all.

If you don't want them, I'll double your money. I have a friend who is looking to get into a "starter" system. These may make good candidates.

[Mongojustpawn]

I thought I really scored, when I saw the horns and big woofers, but at $5, what the heck, they definitely can get loud, though a little shrill, harsh sounding, when pushed, tried some jazz,blues, big band, blue grass, zeppelin, skynyrd, etc, anyway seem to do best with the bluesy, jazzy stuff. I'm feeding them with a Kenwood vr305 and a pioneer cld-s201 cd/ laser disc player.

[SunnyDaze]

They'd make good kitty cat coffins. The horn doesn't even contain a real compression driver, it's a Piezo horn.

I'm guessing there's a terrible gap from around 1000 Hz to about 7000 Hz. Piezo horns are incapable of going very low.

If you google "Radio Shack Catalog Archives" and look at the 1995 Catalog on page 68, you'll find your speakers. They were $150 each new.

Or just check this out: http://www.radioshackcatalogs.com/catalogs/1995_small/

[Mongojustpawn]

8wofF, Excuse my lack of knowledge. What is a comprehension driver, a tweeter? I don't know what you mean by piezo horn, except that it likely sucks, the frequency gap I get. Oh well, I bought some cheap speaks, at least they were only $5. I was suspect of the brand, but too cheap to pass.

[SunnyDaze]

In the simplest terms, a compression driver is a loudspeaker driver or diaphragm that is mounted to a horn.

Compression drivers operate by having a diaphragm with a larger surface area than the throat (opening) of the horn to which it is mounted; this difference in surface area creates a compression ratio that is equal to the surface area of the diaphragm vs the cross sectional area of the smallest point of the horn throat.

Think of an internal combustion engine; a typical Ford 302 has a compression ratio of 9:1; the area of any given cylinder and its combustion chamber is 9x greater when the piston of that cylinder is fully recessed as opposed to when that piston is fully extended. The in and out movement of the compression driver creates a compression ratio in the same fashion. If you think of the chamber whose rear boundary is the diaphragm itself and whose front boundary is the cross sectional region of the horn throat with the smallest diameter, then you have a system that is analogous to a piston in an engine. The compression ratio of a horn driver is simply the ratio of the volume inside that chamber when the driver is at its rearward most excursion to that of the volume inside the chamber when the driver is at its maximum forward excursion.

That being said, compression drivers provide a much more efficient method of coupling the surface area of the driver to the air than that of a conventional dynamic driver.

Horns offer a lot of other benefits as well, but, I'll let you do your own homework on that.

A piezoelectric tweeter is a tweeter that uses a piezoelectric crystal instead of a magnet assembly to serve as the drive motor for the diaphragm. When an electric current is applied to a piezoelectric crystal, the crystal deforms by bending proportionally to the applied voltage.

Piezoelectric tweeters generally don't have the ability to reproduce frequencies below 6000-8000 Hz with any desirable fidelity.

Do not be suspect of Optimus. Like most brands, they made some good stuff and some bad stuff. Granted, their good stuff will never rival Legacy or Eggleston Works, but a recapped old pair of Optimus 5's will catch you by surprise!

[Sir Thrift-a-Lot]

Do not be suspect of Optimus. Like most brands, they made some good stuff and some bad stuff. Granted, their good stuff will never rival Legacy or Eggleston Works, but a recapped old pair of Optimus 5's will catch you by surprise!

Yep, if those had been Mach Ones with a 15" and a horn, the conversation would be going very differently.

I have an old pair of Nova 8s that punch well above their weight class.

[Mongojustpawn]

Thanks guys, 8w, your explanation was very explanatory, I'll just have to keep looking, even a blind squirrel finds an acorn once in a while, meanwhile these will be garage gear.

[SunnyDaze]

If you tell us what kind of music you listen to or what kind of sound you are after, we might be able to offer suggestions as to what sort of speakers / amp / gear to look for.

One thing you might do is try to see if you can modify those Optimus speakers you bought. If the Piezo driver is attached to the rear of the horn with a 2, 3, or 4 bolt pattern or a standard 1" or 1 3/8" threaded opening, you may be able to sneak a real compression driver on there.

[Sir Thrift-a-Lot]

It won't help.   They have no real bass either as the cabs are far too small for a 15".

[SunnyDaze]

They have no real bass either as the cabs are far too small for a 15".

Indeed, they are a bit small to dig down deep. 

I'd buy them for $5, even knowing what I know of them.

Mongo, when Tom gets the new shop up and running in full force, you'll be able to go and experience various loudspeaker and amplifier combinations. Once you find a "sound" that suits you, things will really take off from there.

[Mongojustpawn]

I was going to ask about modding the horn. My music tastes are varied, used to lister to Wduq, still stream it sometimes,  like wyep, dve, 3ws, c&w, it depends, mostly the old stuff, bluegrass. I plan to make a trip the shop, please give me a shout when it's up and running. I like looking at gear, even if beyond my means.

[Sir Thrift-a-Lot]

I like looking at gear, even if beyond my means.

Especially if it is beyond my means.

[Mongojustpawn]

Yeah, That's what I meant.