Altec 828 project

[hifiapart]

Hi,
This is the next project on the list, a reduced volume 828 box to be made from 18mm birch plywood with relevant bracing etc...

Horn remains identical to the Altec 828/825 box; Bass reflex volume is lowered to 265ltrs (9.4 cubic feet) with back of the horn flares open (like older 825/828). The 825/828 with closed flares = 10.6 cubic ft.

Port will be tuned as the 825/828 to +/-50hz, front panel can be removed so fine tuning will be done for room/ear with "temporary" panel. Once set final panel will be made.

Attached is image of plots of regular 828 (white) & this "smaller" one (red) with 828/825 port as reference. Will try to tune lower but not convinced that it will do any good.

Comments welcomed.
Tim

[robertbartsch]

...great project.

If your planning on using these at home, I assume you are not married; right?

...anyway, I owned a pair of Altec VOTTs for 30 years and miss them so much, I am currently acquiring the components to assemble a replacement pair.

The best feature of Altecs are there extremely high efficency (sensativity) ratings. Obviously, bass horn enclosures enhance efficiency. If you have been to a great movie house, you have probably heard these often.

What model components are you planning on using?

[hifiapart]

Robertbartsch,

Married yes...the dimensions are a bit smaller than the a5 or a7s, less wide by 2.4" and height is less 6.5" and a bit deeper and as the rear of the flares are open volume of BR is okay. This in fact makes them visually quite a bit smaller, as you can see in the attached image. blank bloc is the dimensions of the 828 box. That got the WAF...

Components are Altec 288h, jabo KH horns along with Altec 416-8a , so all is set!

Tim

[hifiapart]

It coming together now :D

[Goodwill_HiFi]

......less wide by 2.4" and height is less 6.5"

Why did you make it narrower? Now it isn't the same horn.

Your construction looks great...... one of these days I want to start building my own cabinets...... I really need to get my garage cleaned out!

[hifiapart]

Goodwill_HiFi,

It is 1.6" less than the 828/825 box, not 2.4" as quoted below (sorry for mistake).

FYI the horn is "exactly" the same size as the 825/828 cabinet, depth, height, angle, radius etc.....

You may notice that the flare is not as thick when it meets the side panel, in fact it has no thickness at all (see image). This is pretty hard to do!!!:banghead:

On the "standard" 825/828 box the plywood used for the flare has most of its thickness (5/8" + angle) when it meets the side panel.

This enables one to make the box slightly less wide. (ohhh WAF :applaud:)

Tim

[Goodwill_HiFi]

It is 1.6" less than the 828/825 box, not 2.4" as quoted below (sorry for mistake).

Well, that's certainly closer.



FYI the horn is "exactly" the same size as the 825/828 cabinet, depth, height, angle, radius etc.....

You may notice that the flare is not as thick when it meets the side panel, in fact it has no thickness at all (see image). This is pretty hard to do!!!:banghead:
It may be close, but I can't see it being the same. There isn't enough room in the design to remove 1.6 inches, at least not on the cabinets I had.



On the "standard" 825/828 box the plywood used for the flare has most of its thickness (5/8" + angle) when it meets the side panel.
Mine were no where near that wide. Maybe 3/8th's on top of the 3/4" sides........ or are you using the cabinet sides as part of the horn, too? It's hard to tell from your magnified picture........ going back to the picture of the whole cabinet it looks like the edges of the side panels are flat and do not add to the horn.

[hifiapart]

Well, that's certainly closer.

Yes indeed, and I sometimes get mixed up between inches & metric:eek:

It may be close, but I can't see it being the same. There isn't enough room in the design to remove 1.6 inches, at least not on the cabinets I had.

Checked on finished cabinets and the exact width of the horn opening is 69.8cm = 27.45" the 828 plan (below) calls for 28" so you are correct a slight bit smaller.

If you look at Mashall Kay's drawings you will see that the 3/8" inch flare reduces the horn width when compared to the 1/4".
I have seen the WE 825 the ends of the flares at the side panels are even thicker, and below is a photo of a mid/later 828 box and you can see the thickness.
The 828 plan does not give the width of the horn but it is the result of thickness of panelling used (5/8" or 3/8")
Hiraga here in France recommends in his article from 1986 to use 25mm (1") side & flare panels :banghead: making cuts in the back to bend....this particular iteration reduces the width of the horn more.:blink:

Final overall width of mine is 73.5cm compared to the 76.2cm of the 825 & 75.56cm of the 828 box.

Some A7's had "plastic" flares from what I have been told and that made for an even wider horn opening....:blink:

Mine were no where near that wide. Maybe 3/8th's on top of the 3/4" sides........ or are you using the cabinet sides as part of the horn, too? It's hard to tell from your picture.

No the flare just ends at the edge of the side panel, like a wedge.
Once again this is a true challenge for the DIYer with basic tools (my situation:o:

[hifiapart]

Photo waiting for finish + front panel, have to decide on port size.

[spkrman57]

You might want to make temporary boards to see what port tuning you want to end up with.

Do you have any test gear like woofertester? That would be the best way to set your port tuning.

Regards, Ron

[hifiapart]

What is a woofertester??

[stephane RAME]

http://www.parts-express.com/wizards/searchResults.cfm?FTR=WooferTester&search_type=main&WebPage_ID=3&searchFilter=WooferTester&x=24&y=9

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=390-803
or
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=390-804

Very good job.

Stéphane

[grumpy]

I will bring this up just one more time, then drop it:

http://audioheritage.org/vbulletin/showpost.php?p=251477&postcount=16

Competition is great, but deceptive (in my view) marketing I can not condone.

[Goodwill_HiFi]

I have seen the WE 825 the ends of the flares at the side panels are even thicker, and below is a photo of a mid/later 828 box and you can see the thickness.
WE? Western Electric? I do not beleive there was ever a Western Electric 825 cabinet. It was an Altec design.



The 828 plan does not give the width of the horn but it is the result of thickness of panelling used (5/8" or 3/8")
I beleive factory was 1/4 inch. It reduces the horn opening by about 3/8ths because the 1/4 inch material is cut at an angle.



Some A7's had "plastic" flares from what I have been told and that made for an even wider horn opening....:blink:
I've heard that, but never seen it. I had a pair of cabinets that used a masonite material. It's a high density fiber board type material. It has smooth sides, but when cut, the edges look a bit like solid cardboard. The baffle board was particle board and the remainder of the cabinet was MDO (not MDF) plywood. Unfortunately, the cuts for the left flares were not in exactly the right spots, so they did not meet the edge of the cabinet correctly. Even if your horn opening is slightly smaller, you'll have careful construction on your side.

[sbjacob]

Photo waiting for finish + front panel, have to decide on port size.
That is very nice work:applaud:

[Goodwill_HiFi]

That is very nice work:applaud:

Yes, I agree!

What kind of finish are you going to do hifiapart/Tim?

[hifiapart]

The finish in on the table for debate with my wife at this stage...
Any ideas?

[Goodwill_HiFi]

The finish in on the table for debate with my wife at this stage...
Any ideas?

Grey or black paint :D

Seriously, what is the rest of the room like, where they will go?

[hifiapart]

Wow been busy...a picture of the "boxes" playing...they sound good (very!) but they will get even better:


Back needs more bracing
Put some wool lining on back & bottom, maybe side?
Place curtain between rear of driver and bottom part of the bass reflex
Put the jabo horn on

Tuning the port with various width boards will be done when I get the Jabo horn fitted (you can see them on the floor in front next to the pig:D). Currently they are at 52hz.

The current horns are mantarays, not bad.

Overall quite pleased with them. Much much better than the BR boxes I had before.

Still thinking of colour/stain to finish:banghead:

Tim

[sbjacob]

Wow been busy...a picture of the "boxes" playing...they sound good (very!) but they will get even better:


Back needs more bracing
Put some wool lining on back & bottom, maybe side?
Place curtain between rear of driver and bottom part of the bass reflex
Put the jabo horn on

Tuning the port with various width boards will be done when I get the Jabo horn fitted (you can see them on the floor in front next to the pig:D). Currently they are at 52hz.

The current horns are mantarays, not bad.

Overall quite pleased with them. Much much better than the BR boxes I had before.

Still thinking of colour/stain to finish:banghead:

TimI went around and around about a color and decided on polyurethane.Can't wait to get them in the house!39581

[hifiapart]

Nice & very impressive!

[sbjacob]

Nice & very impressive!
Thanks I love alot of bass and these have alot. I fired them up in my garage and stuff was rattling off the walls.:rolleyes:Sorry about the chim in on your post.

[stephane RAME]

Hello,
Congratulations, a very good job, still to be optimized.
Stéphane :applaud::applaud::applaud:

[robertbartsch]

Nice cabs!

..your wife must be a saint.

[hifiapart]

My wife likes them more like this :

[Goodwill_HiFi]

My wife likes them more like this :


Can you tell me more about these round horns? It seems a lot of VOTT systems I see pictured, from Europe, use these horns.

A silver pig?

[hifiapart]

Yes a silver pig...maybe we will get a gold one someday!

The Jabo horns are made by Werner in Germany, he sells on ebay and they are very well priced.

He has several horns 30, 50 and 70cm (800hz, 500hz and 400hz). He also machines some very nice adaptors to go from 1" or 1.4" to 2" (dia of the horn mouth). You will locate him at ebay by the name of mast_mutter. He does not speak English at all but manages to correspond by email in English. He is sometimes slow to respond but does.

I have just been listening to these and they really throw a great clean, articulate sound with a fantastic soundstage.

I also got his xovers that use line tx's and am currently comparing them to ones made by "la maison de l'audiophile". I feel that Werners are light years better!

Tim

[stephane RAME]

Hello,
Do you have pics of your xover.
Stéphane

http://audioheritage.org/vbulletin/showthread.php?t=11750

[Fangio]

The Jabo horns are made by Werner in Germany, he sells on ebay and they are very well priced.

He has several horns 30, 50 and 70cm (800hz, 500hz and 400hz). He also machines some very nice adaptors to go from 1" or 1.4" to 2" (dia of the horn mouth). You will locate him at ebay by the name of mast_mutter.
Seems Werner Jagusch likes JBL a bit also.. ;)

Very good job so far Tim.

[hifiapart]

Image of xover for Stéphane

[Goodwill_HiFi]

The Jabo horns are made by Werner in Germany, he sells on ebay and they are very well priced.

Is this their primary attraction? To me, they look odd, yet I see them in pictures quite often...... round at least, maybe not Jabo/Werner. If Werner is the company, what is Jabo?

[hifiapart]

Sorry my phrasing was not clear; Werner is the name of a person not a company, he calls them Jabo, no idea why but maybe tat means something in German?

I may get hold of some multi-cell horns like the 1005 from altec and give them a try. This is one of the great things about having this kind of speaker. No "plug & play" solution and very easy to make changes, xovers, horns, drivers....good stuff.

[Goodwill_HiFi]

Sorry my phrasing was not clear; Werner is the name of a person not a company, he calls them Jabo, no idea why but maybe tat means something in German?

So is Werner a reseller, or does he actually produce the horns himself? What are they made of?

[hifiapart]

Werner makes them himself from what I understand.

He uses VOT's (825/828 box) as you see in the image sent by Fangio.

Made from fibreglass and with a very solid aluminium insert at the driver end.

[hifiapart]

So got around to painting and went for cast iron colour.

[Earl K]

Very Nice Project Tim :cheers:
It makes me wish I had more room here for something similar :p

I love the look of those big Jabo horns :thmbsup:

>< cheers :)

[Goodwill_HiFi]

Very Nice color..... is it basically a dark grey, or does it have the metallic look, up close? I've seen and used a "cast iron" color in spray cans that is a gray metallic.

Will you be painting the horns and fabricating a mount for them? What are the blue boxes?

[theophile]

Great work gentlemen! :applaud:

Has anyone compared Werner's horns with the Azura Horns?

[hifiapart]

Cast iron is a dark grey with a hint of blue (RGB = 40/42/50), it is not metallic.

The blocks are my from my wife's personal collection of....Yoga blocks. They are quite cool (and so is she:D) because they compress very slightly and make a nice support that is very stable.

I will be testing other horns so the support for the compression drivers is temporary. When I am set on horn I will make an appropriate support.

Will post images of various evolutions.

[sbjacob]

So got around to painting and went for cast iron colour.Wow one of the coolest systems and most inviting looking listening areas I have seen. Awesome Congrats :beach:

[Fangio]

Werner makes them himself from what I understand.

He uses VOT's (825/828 box) as you see in the image sent by Fangio.


Werner has been a former employee at ACR as far as I know, and may have been involved in their distribution channels as well. I've had a pair of their wood horns, quite a familiar name in the audio world at least on the Old Continent. They still make car audio nowadays.

The Jabo horn line seems to be very successful for him.

Good choice on the cabinet color, I like it. :)

[demon]

your speakers look fantastic! congratulations!
i hope you have a good time with em.

i heard some jabo horns the last years and i think they are ok. most of the time they where married to the BMS coax-driver, so i can only speculate how good they will sound with ... ;) ... a real driver.

cheers
mikey

[chronomastersvo]

:wave:Hi there in the outer space.
I've found these nice forum yesterday.
My name is Christof, I'm 45, married and I have a wonderfull wife which understand my hobby.
I've build up this 828 custom made two years ago. I used a construction plan from Werner Jagusch. I also use his Jabo tractrix horn and a autotrafo crossover made by him.
I had several speakers but the Vott is the best I have ever heard.
I use a 416-8a and a 288-8L.

http://www.bild-hoster.de/images/Chronomastersvoice/828.jpg
http://www.bild-hoster.de/images/Chronomastersvoice/anlage.jpg

http://www.bild-hoster.de/images/Chronomastersvoice/vott828.jpg
http://www.bild-hoster.de/images/Chronomastersvoice/vot1.jpg
THis is an actuel picture, but there was too much light in my wintergarden.
http://www.bild-hoster.de/images/Chronomastersvoice/wintergarten_1.jpg
Have a nice day
Christof

[hifiapart]

Things have moved a little and now hosting Goto Horn ontop. The whole things makes sense to me. A very natural sound and can listen for ages.

Trying to see what I could do to get things going below the 50hz region, any ideas???

Tim

[stephane RAME]

Hello,
Configuration as interesting!
What are the frequency of cuts?
They are geometrically aligned?
Best regards.
Stéphane

[hifiapart]

Bonjour Stéphane,,,,

They are physically aligned +/- 2 cm, the xover are :

PLLXO at 270hz
Bi-amplified
passive low pass 1200hz, then band pass 1200hz > 5800hz the high pass 5800hz.
All 6db 1st order.

The bass is inherently weak below 50hz (vot) but the upper bass are so musical. Need to fill below 70hz with something.

What about a tapped horn?

Have some 416-8a or 515b's spare so maybe they can be used for a sub???

Tim