Questions on an Altec 1234

[rockman]

I have waded through pages here and tried the search function which has not helped much. I say this to ask questions on a pair of speakers I bought which are the 1234's. The 808-8b diaphragms are toast and the old woofer's were too having been poorly replaced with a set of peavey Black Widows which did not fit right anyway. I intend to restore these and have two ways to do so. Either find OEM or equivalent. The purist in me says stay as close to original as possible and I have found some woofers. The diaphragm however is a different story and I would like to get suggestions on what to get for a replacement. There are chinese ones for sale everywhere for $10 up a pair with some pretty negative reviews. I see Radians for like $90 and they have just as many bad reviews. I see no actual Altec parts and wonder if there is perhaps a JBL that would fit? I have a sweep generator if required to center the diaphragm exactly which seems to be recommended even though it looks like the diaphragm is supposed to be self centering. I have checked a cap on each crossover and it was very close to spec with low ESR so I think the crossover is OK. This has to be the most basic crossover I have ever seen and is it good to keep or should I upgrade something?

Which leads to the second basic question of is there a better horn and woofer to use here? I know using original spec parts makes for more value if I wish to sell them. And I might since as of now I have no idea what they will sound like. Has anyone had experience rebuilding these with OEM equivalents and or new possibly better components?

New user by the way to Altec and to this forum.

[gdmoore28]

Welcome to the Lansing Heritage board, Rockman! It's always good to have another Altec fan on board here. This site, along with AudioKarma, and the Altec Users' Board all have very dedicated and knowledgeable experts on these systems and are eager to help you with your project. (There's a fellow on AK who is basically asking the same questions as you about some 1234s. I assume that's not you, is it? If not, you might be helped, too, by following his project there:
http://audiokarma.org/forums/index.php?threads/the-altec-valencia-mock-valencia-project-help.794130/#post-10981044.)

The specific answers to your questions will depend on how you intend to use your 1234s: for sound reinforcement (PA) or for home hifi. If you can let us know which way you want to go, we can offer indepth suggestions.

GeeDeeEmm

[rockman]

Welcome to the Lansing Heritage board, Rockman! It's always good to have another Altec fan on board here. This site, along with AudioKarma, and the Altec Users' Board all have very dedicated and knowledgeable experts on these systems and are eager to help you with your project. (There's a fellow on AK who is basically asking the same questions as you about some 1234s. I assume that's not you, is it? If not, you might be helped, too, by following his project there: http://audiokarma.org/forums/index.php?threads/the-altec-valencia-mock-valencia-project-help.794130/#post-10981044.) The specific answers to your questions will depend on how you intend to use your 1234s: for sound reinforcement (PA) or for home hifi. If you can let us know which way you want to go, we can offer indepth suggestions. GeeDeeEmm No that was not me. I was not aware of that forum and they seem to have far more on the 1234's so I will have a look tonight. I have no idea of the sound quality possible with these but my purpose will be 2 channel in my shop. Yes I do want them to sound good but unless there is a reason tend to stay with experiments that do not involve cutting up cabinets. Crossovers and driver substitutes are fine. I would rather build new crossovers than destroy old. The only missing piece of the puzzle right now are diaphragms for the 808-8B driver. Do you have any suggestions?

[gdmoore28]

OK, here we go. The 1234 was designed for sound reinforcement (PA) use. That means that midrange/mid highs/upper bass/ frequencies were emphasized in order to cut thru the noise and not waste power on the lower frequencies that were assumed would be handled by subwoofers. For home use, we need different emphasis: ideally a flat response from the lows thru the mids and to the highs. If you want your 1234s to more closely adhere to these qualities, you will need to do the following, in order of relative importance:

- Build and install the very simple and cheap Altec 30923 equalization network. This simple mod will make an incredible difference in the tone of those cabinets by dramatically decreasing the mids and making the highs and lows more apparent. This simple circuit installs between the crossover and the horn drivers. Simple. (The schematic is all over the internet. Just Google it.)

- Your horns should have the Symbiotic diaphragms. They do not have very good hi frequency extension. Exchange them for GPA 34647 diaphragms. Do not buy the Chinese diaphragms. They are junk.

- The changes made to this point may deliver the smoother hifi sound you are looking for. But if you want to experiment even more, change the woofers. Yours are musical instrument woofers and don't deliver the deepest bass response. Change to the Altec 416 or 515. You may need to alter your cabinet tuning a bit by changing the ports. (I may be totally wrong, but it seems I remember that the 1234 needs two 4" diameter, 4.5" long ports to tune for the Altec 416 woofer. Others will check me on this, because I could be off.)

- Crossover: If yours are ok, just stay with them. They are very simple second order crossovers with nothing special to them. Altec Model 19 crossovers are the gold standard when it comes to networks for these types of builds, so if you are intent on building one, go for those. The schematics are all over the internet, again. But adding the 30923 network behind your current crossover will give you the Model 19 shapes, but without the adjustability.

Here's the most popular version of that network, the Z19:

http://audiokarma.org/forums/index.php?attachments/z19-drawing-png.355959/

This is just a very quick and dirty summary of the steps needed to get the best hifi performance from your cabinets. As always, there are many, many other considerations and options involved, and hopefully some of the other guys will chip in and offer their tips.

If you decide to go this direction, let us know and we'll get more indepth as needed.

GeeDeeEmm