Atlantic Oracle 4

No recap here. I think they sound a little better now than when I first hooked them up. I haven't decided if I will recap or not.

When I had them cranked up I started to smell something hot. I thought "oh shit!". It was just the resistor on the crossover board. It was getting super hot for some reason. It doesn't seem to be a problem now after running them for a day. I had them going all night.

I just got them this weekend so I haven't been able to do anything with the passives yet until I can get some new surrounds ordered. I wonder if the 12" passive on mine will make it a little more balanced? The boominess in the bass could be room placement. Maybe moving them into the room some and away from any corners might help some.
 
With no surround on the PR it's definitely not going to sound like it should - not only is the PR not operating but the cabinet is open too.

The resistor heat that went away later might have had something to do with caps. If they've been sitting a long time one might have decomposed and drifted way off. I can't see it healing itself though unless it was an electrolytic reforming as it played. Trouble is you can blow a mid or tweet with too much low freq. information. I'd put some Daytons in there before you lose a driver, cheap insurance. Just my 2 cents.
 
Your right. Maybe that's why the mid's seem a little hot. It might be fun trying getting the bigger Dayton's on that board. I might have to run a couple in parallel on the bigger ones to get them to fit.
 
I think that's what I did, but in my case it was a matter of using what I had to get the right value. May want to check those resistors while you're in there.

Maybe we oughta have an Oracle Shootout at the KC Twangfest one of these times. :D I wanted to bring mine anyway, if I can get em in there without taking any of the covers off, to preserve the visual effect when people find out what's under there.
 
I'v recently aquired a pair of these. I refoamed the woofer and passive to see what they sounded like. Caps probabley need replacing- Any recomendations on which caps to use? Thanks.
 
Hi Coryk...I have recapped a number of (not esoteric but certainly hi-fi) speakers using the yellow and black Dayton metallized polyprop. caps from Parts Express. They are relatively cheap as audio caps go. Any film cap will get expensive for larger values though. I don't remember offhand what is in the 4's but if there is something like 30 or 50 uf in there, it will be in the bass circuit, and you can use a nonpolar electrolytic (also available at PE) for a lot less $ and smaller size to boot.
 
Here are pics I happened to find of Atlantic Oracle 3 speakers. You'll note some sort of grill assembly encloses the top, but it's removable (and losable, which seems to have happened to the Orcale 4s, above....)

AtlantisOracle3sPolk5bTeac144001-1.jpg


AtlantisOracle3sPolk5bTeac144007.jpg
 
The top cover is a particleboard frame open on all sides, no bottom, that sits on velcro dots. The top (at least on my 4's) is smoked glass. I think the frame probably causes some distortion and defeats the purpose (at least partially) of mounting the upper drivers without a baffle in the first place. Sometimes I listen with the covers off.
 
Oops. I see you do report that at the top of the thread. Hadn't read closely enough, my bad.

I was just researching Atlantic speakers because someone said they had some for sale. But in another oops, turns out the ad had the name wrong....
 
Well, now you know all about Atlantics in case you ever actually encounter a pair. Time well spent. Isn't trivial knowledge a great thing?:tongue:
 
I have some info on the Atlantis Oracle lineup that I can add. I was a store manager for Team Electronics during the late '70's, when these were current models.

There were four models in the Oracle line, the I, II, III, and IV (creative, eh?). All of them shared some basic design features: open mounting for the 1" dome tweeter and 2" dome midrange, and a bass driver with a passive radiator. The III and IV added an open-backed 4" cone midrange in a transmission line enclosure. The Oracle I used a 6" active/8" passive, the Oracle II used an 8" active/10" passive, the Oracle III used a 10" active/12" passive, and the IV used a 10" active / 15" passive. The cabinets were a nice solid 3/4" particle board with walnut veneer on all four sides. The top enclosure was a particle board frame covered with cloth and open on all four sides, with a smoked glass top. The crossover was mounted in the top enclosure, and used iron-core coils instead of air core, and there was an 'autostat' breaker for overpower conditions.

As noted, they were designed for Team Electronics by in-house staff, and manufactured by Becker Electronics. The initial design goal was to look like a Dahlquist DQ-10, but to sound like a Quad electrostatic; lofty goals for a house-brand speaker, but they managed to hold their own.

My personal favorite was the Oracle III; the smaller models were a bit light in the bottom end, and the IV was a bit flabby when extended down low.

Team Electronics commissioned a special demonstration box for store demos that allowed each driver to be automatically switched on or off, based on encoded tones. They had a demo tape created (and later, a 45-RPM vinyl disc) of "Time", from Pink Floyd's "Dark Side of the Moon". There was a spoken introduction of the features of the speaker, and then the music started. The first alarm clock started ringing with only the tweeter playing, and as more bells chimed in, additional drivers were added in, culminating with the big bass note. It was a quick education, and an effective demonstration.

One simple modification is to mirror image them, which was very simple to do.

Someone else mentioned a vertical alignment, which is what I ended up doing with my pair. I built a new top section to handle the height, and added a second tweeter and upper midrange to each side that were mounted facing to the center. The speakers were placed about 1/3 of the way into a long living room (13' x 28'), and about 3' out from the walls.

The end result was one of the most amazing 3-D sound fields that I've experienced, with a soundstage that you could not only walk up to and into, but walk behind. Ultimately, mine failed due to foam rot, before the internet made it easy to find replacement parts.
 
Great info, thanks for sharing! I agree my IV's are a tad boomy in the deep bass dept., always wanted to figure out a way to tighten it up, perhaps by adding mass to the passive. Just haven't tried it yet. I was just listening to them last night, and they have some of the nicest mids and highs of any speakers I've owned.

Don't suppose you have any pics of your modified III's?

Where was the store you managed? I found my pair here in central MO.
 
No pictures of the vertically-modified Oracle III's; at least not any that would show anything. The upper box ended up about 2/3 the height of the lower. The mod was extremely easy, as all three external drivers are mounted on the same header, so you just wiggle it loose, stand it up, and stabilize it, and you're good to go.

I worked at stores in Minnesota and Oklahoma.

I agree with their performance on female vocals; in a dark room they could be scarily amazing.
 
Cool, thanks. I need to print out the background info you posted like the Becker Electronics connection. I don't remember if we figured out who made the drivers, was it Becker?
 
Yes, the drivers and systems were made by Becker. I think that somewhere in my archives I have a Becker catalog from the era that may cross-reference part numbers. I'll try to look this weekend.
 
I've just acquired 2 more pair of Oracles from AKer SPLdb - I believe they are III's as they have the 12" PR. They are in need of foam and caps but little else. Nobody really needs three pair of these, but on the other hand, if three were stacked laying on their sides, the upper drivers become a sort of line array. I think I'm going to have to do that, because it's a rare opportunity for this many pairs to be together. :rockon:
 
There's no way to know, but I'll bet no user has ever had three pairs of these deployed at once before....
 
You must log in or register to reply here.

Similar threads

bluefan
Realistic Nova 9 - recap help
2
Replies
38
Views
4K
grandville45
grandville45
harry398
Silk dome tweeter replacement question
Replies
4
Views
505
harry398
harry398
N
cerwin vega D9 VS AT 15...... JUST FOR FUN
Replies
4
Views
7K
nickword
N
gearhound
Any info on Audio Research ROR speakers?
Replies
11
Views
3K
gearhound
gearhound
johnfalc
Found a box of drivers in the garage
Replies
1
Views
578
vegabass25
vegabass25
Back
Top Bottom