Foam Core Board Speaker Enclosures?

iko

Ex-Moderator
Joined 2008
Nice surprise at work today: a parcel! The tang bands arrived. They seem so tiny! I'm worried... So I mounted them quickly into a couple of empty server boxes but they don't sound good. Guess I must be patient to hear them in a proper enclosure.

The vifas are even smaller! :O
 

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frugal-phile™
Joined 2001
Paid Member
Nice surprise at work today: a parcel! The tang bands arrived. They seem so tiny! I'm worried... So I mounted them quickly into a couple of empty server boxes but they don't sound good. Guess I must be patient to hear them in a proper enclosure.

What do you expect they are, afterall, Dell Boxes :)

Don't forget that you want to get at last 100 hrs on them before paying much attention to what they sound like.

dave
 
Nice surprise at work today: a parcel! The tang bands arrived. They seem so tiny! I'm worried... So I mounted them quickly into a couple of empty server boxes but they don't sound good. Guess I must be patient to hear them in a proper enclosure.

The vifas are even smaller! :O

Like Dave said. They need time to break in. I would play them in those boxes while you build the real ones. That way, the drivers will be broken in when the time comes.
 
So today I picked up the trim pieces and realized I can't cut them until the grill cloth is in place so I went on to doing the wood oil. Watco - Danish Oil, Fruitwood. Looks really good but...

...note to self: Don't buy dollar store masking tape. How stupid is that? I now have oil where I want to glue on my trim so I will be cleaning with alcohol and sanding before applying the trim.

I added a small piece of wood [3/8" X 3/4"] under the foam right where it meets the corner. This will add some strength for when I put the grill cloth on and as a bonus, it gives me a handle with which to carry the boxes.

That's it for today, hopefully cloth tomorrow.

6L6, nice to see the progress. :)
 
Founder of XSA-Labs
Joined 2012
Paid Member
Thanks to Cal for turning me on to this thread.

What's the concensus on EL70 drivers for this project?

I have seen some not-so-favourable mention in recent posts regarding the prospect of using EL70s, but xrk initially thought they might be a good candidate.

Has anyone tried it?

I think I said CHR70, but these look good too. I think the Cornu is very tolerant of different drivers.
 
Founder of XSA-Labs
Joined 2012
Paid Member
Thanks for the reply. Would you be so good as to have a look at the T/S numbers of the EL70s and let me know what dimensions would be ideal for them?

All I do is scale the channel depth so that the throat area is at least as big as the driver piston area Sd. For the EL70 follow the 70 x70 cm plan and make it 3.9 in deep (4 in is probably ok). One thing that concerns me with these drivers is that they don't have a rising high end like TB W4-1337 which looks like a tweeter from 10k to 20k Hz. The Cornu puts out so much bass it can really benefit from an 'unaturally' high end to get decent highs to compete with thr bass. Usually you have the other problem, not enough bass. Also, if you don't need the horn to reach down to 38 Hz you can scale it smaller, the low bass tuning freq scales proportionally.
 
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iko

Ex-Moderator
Joined 2008
I am happy with the appearance for something called underlay. Last pic shows the piece I added for strength. In that pic you can see the oil contamination on the edge that I now have to deal with :(

Bad Cal!

Too bad about the oil spill Cal!

Quick question for you, since you have the same plywood as I. Do you have any idea what the top veneer is? Does it look good with the oil on? I'm not sure whether to go for shellac or simply do it with oil like you.
 

iko

Ex-Moderator
Joined 2008
What do you expect they are, afterall, Dell Boxes :)

Don't forget that you want to get at last 100 hrs on them before paying much attention to what they sound like.

dave

Thanks guys! Funny thing is, I had some old 5" mid/base drivers from an old Kenwood stereo and put them in the big Dell cardboard boxes in parallel with the vifas. It completely floored me: full nice bass and mids, and there are highs too. The cardboard boxes beat my other speakers. :mad: The cornucopya has to be better, I can't keep the cardboard in the living room.:gnasher: