Rebuild Altec Model 5 cabinets

I'm a recent convert to vintage JBL and Altec Lansing gear and would appreciate some advice.

I've just picked up a pair of Altec Lansing Model 5's (my first Altec stuff) for $20cdn and the cabinets have some water damage. The sound is this awesome warm tone with crisp highs (dual cone tweeters).

I think the sound is worthy of new cabinets and I don't think this model is particularly sought after so I'm torn between replicating the original boxes and trying something new.

For replicas I would use a heavier MDF and bracing inside.

My question is can the shape of the cabinet be changed but its volume kept the same and expect close to original performance?

I know a lot of testing goes into commercial cabinet designs but the old gear seemed to pay less attention to this. I've also considered going for a larger and heavier cabinet and keeping the same port size.

Thanks for any ideas.

Welcome to the Asylum!


If the woofers are in original condition and your happy with the "tuning" they have in those cabinets then you should be able to reproduce them in MDF with finished veneer. Keeeping the volume the same should give you similar if not exact tuning. Bear in mind these points
1. If you decide to relocate the vent to the rear it may affect the tuning a bit. Keep the vent's opening inside the box away from the woofer frame and at least 1 inch from any walls.

2. THe high frequency sound may be altered significantly by moving the tweeters around on the baffle board. Take a piece of wood and cut a hole for the woofer. Move the tweeters around on the board while playing a familiar track through the speaker and see how placement affects the sound. You may find another position to be more suited.

3. The crossover caps are probably old and dried out. New capacitors and level controls are good idea on old speakers. Put .01 uf caps in parallel with the capacitors to improve the sound a bit.

4. If the surrounds are dry and brittle here is a link to someone that can repair them for around 60.00 US a pair www.speakersaver.com

5. Ou could alter the tuning a bit with a larger/smaller cabinet and different port tuning to create a sound more to your liking. You could add or subtract 10 % to the volume and adjust the port tube accordingly. If you can get the T/S specifications for the woofer you could simulate a different cabinet volume using boxplot, a free ware program available on the internet. Since your looking to build cabinets you have an opportunity to create what you want, that is the fun in building speakers.

6. Post pictures before and after , we like to see projects. Here is one of mine:
http://audioheritage.org/vbulletin/s...ht=4411+clones

Cool, post some pictures.



I saw your post and thought strange as I found some model nines today, from the same series.

Haven’t had a listen yet

The Cabinets are in very good condition with solid bevelled timber front edges and seem to be well constructed.

I will keep you posted on fixing them up.



If it is just water damage to your veneer it is possible to have it repaired.

I have no idea yet whether it is possible to find bits and pieces for the drivers.

I will take some pictures and post them.

Thanks for the replies.

Lot's of good suggestions.

I'm going to look for the woofer specs when I open it up and get some model info and check out Boxplot. That sounds fun.

In any case I was going to mirror the tweeters around the woofer center.

On the damage, unfortunately they were in a little standing water long enough to swell the corners a bit. Still solid but not pretty. So starts my project!

The model 5's have the same beveled timber on front. Thats one thing I love about these older boxes. You can work on them.

I'll get working on it and put some photos up soon.

Later.