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Zenith Allegros: Guts and All

The 3000 series were part of a system called The Wedge. If I remember right it was 15 wqtts a channel RMS. It did sound pretty good for a TV manufacture. Even back then Zenith was making great TVs wevsold all of them back then.
 
I've seen several in person and at Goodwill stores. Family have owned a few also.

From what I remember the allegros were built fairly good in the early days, but then evolved into the same drivers put into Far cheaper particle board cabinets with glue on stapled backs and so on.
The later ones had maybe 3/8" particle board and sounded cheap and thin when you hit your fist on them.

The early ones were more like 3/4" board of some type, but with screwed on backs, and felt Far more sturdy

My memories of the sound, was decent for the day, but nothing truly special. A lot of bass or at least somewhat exaggerated bass due to a fairly large cabinet and the port tuning.

Think, fairly similar to what Radio shack had in an equal sized box....Decent but not earth shattering, nor bad at all.
 
Tube Radio said:
Most if not all the Allegros were in boxes that were too small.

That's most of their problem.
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The bigger models were for sure in too small boxes, but the smaller ones almost too big of boxes.

Seems like the wanted the whole line of speakers to be somewhat similar in size.
 
I think I disagree with the comments about box size. I believe the Allegros were designed using Thiele Small parameters - oddly, Zenith was one of the earlier adopters of the design method, even if in other areas it was pretty retrograde. An advantage of big corporations is that they have a lot of experienced engineers and designers, and if they want to, they can do things right and efficiently.
Obviously the Allegros were mostly designed to work with Zenith electronics, which limited the amount of power and frequency range that the speakers were expected to work with, and this was probably a limiting factor in the performance of the speakers. But Consumer Reports routinely rated the Allegros highly for their bass within their price ranges, which suggests that Zenith succeeded in wringing what bass extension and power could be found out of what were, and still are, cheap speakers.
 
Nat said:
I think I disagree with the comments about box size. I believe the Allegros were designed using Thiele Small parameters - oddly, Zenith was one of the earlier adopters of the design method, even if in other areas it was pretty retrograde. An advantage of big corporations is that they have a lot of experienced engineers and designers, and if they want to, they can do things right and efficiently.
Obviously the Allegros were mostly designed to work with Zenith electronics, which limited the amount of power and frequency range that the speakers were expected to work with, and this was probably a limiting factor in the performance of the speakers. But Consumer Reports routinely rated the Allegros highly for their bass within their price ranges, which suggests that Zenith succeeded in wringing what bass extension and power could be found out of what were, and still are, cheap speakers.
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My comments about box size were based on having seen the entire line up side by side.
All 3 main models, the 1000, 2000 and 3000, were close in size to a degree was all I meant.

I agree they did design them with T/S specs, but at the same time, seeing the relatively small differences in cabinet size from the 1000 to 2000 to 3000 models, it appears they were considering cabinet size first was all.
 
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Kevin - my assumption was that the discussion was about all the Allegro models, the vast majority of which were sold were the little speakers attached to consoles of various sorts, usually with a 3d grill with a square port (or, actually, a port fascia). These were the ones that I believe Consumer Reports graded highly. The 1000 on up were less common, and because they were significantly bigger, I do not have any difficulty believing that Zenith designed them trying to keep the size down. Very often, a driver can be used successfully in different size enclosures (with penalties in efficiency or low end extension - Hoffman's Iron Law). So I'm sure you are right that the drivers can be used going deeper, but that's assuming that size isn't a problem. And for many consumers, it is a huge problem. So Zenith probably made the decision to go small. The same decision seems to have worked well for Bose.
 
I love the foster tweeters as well.

Once bought a set of five someone was selling.

I once had a pair of allegros.

Regretted not using the woofers for something.
 
Okay......just bought the guts out of zenith MC3000 model, and built my own MDF box. It is the size of the original speakers, but slimmer, and several inches taller. Same cubic feet inside.
Installed the woofer and tweeter and crossover. This one has the variable Tweeter level control.

The outcome? Actually exceeded my expectations in some ways. They are fairly efficient. A true 90 db/watt I would guess if not a bit more, matching what they are rated at.
They sound actually very clear and clean. The treble is very good and so are the mids. This is a very neutral and clean speaker, with a tad of boomy bass around 90-125 hertz.

They take power quite well, play fairly loud. Diana Krall sounded quite in the room. I expected a lot more muffled and lacking detail.

The ONLY let down. In my MDF box, of same dimensions as the original, and same port tuning frequency, they seem to lack a bit deep bass wise. But they have such a good mid bass sound, they seem VERY listenable for long periods. Not warm sounding, but just slightly full sounding.

Compared to a modern day speaker, ....honestly fairly comparable in some ways, but just a big box, that does not do the deepest bass with enough impact.
Very impressed overall.
 
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Tube Radio said:
Some here have gotten better results putting the drivers in larger cabinets.
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The box I just made, 1.85 cubic feet, is nearly identical to the volume of the original MC 3000 speaker.
I found T/S parameters on another site, but now am not sure they were correct.

My modeling software, indicated they would do better deep bass wise in this cabinet.
They are not totally lacking deep bass wise, but for the box size a bit let down.
 
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I have a set of them. 10 inch woofer. Either got them free or really cheap. Corners are beat up.
Seem rather cheaply made, but sound half decent. Looking to replace them, but moneys tight right now.
Also have a vintage pair of Advent 3's. Have them hanging on the wall near the ceiling of my basement.
My wife complained about the bass, is she joking, with 6 1/2 inch woofers? She made me disconnect them.
I have the wires running through my close-mount drop ceiling to the other side of the room. Not going to remove those wires. This type of ceiling is a real pain. Remove one tile and the rest around it will fall.
Need to get rid of a lot of stuff, so I can rearrange the room. Maybe put the Allegra's on the floor where the Advent's are? Everythings a mess right now...
 
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