Altec 288's to JBL 2" Adapters Will this work?

[mlr]

Hi.

A little while back I saw a set of adapters (Altec 288 to JBL 2"/4 bolt) sell on ebay for in excess of $350.00 (as I recall).

Is there something magical in those things? Couldn't one simply weld up a set?
1 flange to match JBL 2"/4 bolt, 1 flange matching Altec 288 (1.25"?)/3 bolt, and
weld about a 2-3" section of 2" inside diameter pipe between the 2 flanges, and
I suppose grind the Altec flange at an angle to approximate the 2" pipe, or weld a reducer into the 2" pipe at the Altec end of the joining tube, and then grind it at an angle to smooth transition from 1.25" to 2".

If that will work... what is the optimum length between the flanges, and are there any drawbacks from mating a 288 Altec to a 2" throated JBL horn (providing the horn in question meets whatever frequency one chooses to cross at)? ie: mating a 288-16G to a JBL 2380 Horn etc.
Out of simple curiosity... what about mating a large format driver to a small format horn? ie: a 288 to a 511?

I could see where large format driver to a small throat horn might be an issue, but I don't see why a 288 would not function well mated to a 2" throated JBL horn.

Why are those adapters worth so much? Is it purely collector value, the 'ebay factor', or something more mysterious? I want to try building a set, so please advise if you have clues. Thanks!

Mike

[bfish]

Hi Mike,

What you have in mind might work, in the sense that some sound will be heard from the horn, but it's far from ideal. You might liken it to the difference between speaking through a passive megaphone vs a length of pipe. Or using an old bucket for a horn.

The exit passage of your 288 is a narrow-angle, tapered conical waveguide, and ideally any adapter should seamlessly continue that same conical expansion until the ID matches that of the horn entrance. If the rate of flare is known, the length can be calculated. Anything less is a compromise that will noticeably affect performance. Even in the best case using a properly cast adapter, the added length will likely affect the horn's dispersion pattern. Reversersing the rate of change, as in going from a large format driver to a small format horn is likely the worst compromise of all.

DIY is my passion, but I can think of no good way to garage-fab a proper adapter that would carry the weight of a 288. Probably why the factory jobs are cast. Even if you find a cast adapter, unless the rate of flare matches your 288, it will be less than ideal.

Even some (non-Altec) factory solutions are seriously compromised, threaded drivers and their adapters come to mind.

[Old Guy]

Jammin Jersey has JBL 2330 for $200

http://www.jamminjersey.com/speakers...=jblcomp#Horns

How much of an issue a 1.5 adapter would be, I leave to GM. But you can get new for $23.

I do personally guarantee it will work better than a DIY. and cheaper.

Note the Paudio is 4 bolt and will have to be drilled.

http://www.loudspeakersplus.com/html...oadapters.html

[bfish]

"Reversersing"???

I shouldn't post before coffee.

Or after a nip, for that matter...

Let's see, that only leaves...

Never mind.

[Old Guy]

Which people?

Jammin Jersey has a decent reputation, for that matter so does Loudspeakers plus. But if they are screwing up I'd like to know.

Assuming you paid by credit card, just file an issue with the card company.

[Old Guy]

Speaker City also has the Paudio adapters..

http://www.speakercity.com/Merchant2...ory_Code=PA-AD

[speakerdave]

Originally posted by Old Guy:
Which people?

Jammin Jersey has a decent reputation, for that matter so does Loudspeakers plus. But if they are screwing up I'd like to know.

Assuming you paid by credit card, just file an issue with the card company.

<font size="2" face="Verdana, Helvetica, sans-serif">Loudspeakers Plus. I'll probably get the item eventually or get my money back--with all the hassle. The caution I suggest is to first call them an ask them if they can actually see the item on the shelf, since my hunch is that is the problem. Or perhaps it was some other human fallibility that spiked up while my order was being processed.

David

[scott fitlin]

Originally posted by speakerdave:
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Old Guy:
Jammin Jersey has JBL 2330 for $200

http://www.jamminjersey.com/speakers...=jblcomp#Horns

How much of an issue a 1.5 adapter would be, I leave to GM. But you can get new for $23.

I do personally guarantee it will work better than a DIY. and cheaper.

Note the Paudio is 4 bolt and will have to be drilled.

http://www.loudspeakersplus.com/html...oadapters.html

<font size="2" face="Verdana, Helvetica, sans-serif">CAUTION IS ADVISED HERE!!!! I sent 58 bucks to those people almost a month ago for a pair of those adapters, ordering on line, and nothing yet. An exchange of emails has died down.

David</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I second this.

I had a terrible purchase experince with Jammin Jersey.

Two years ago, I ordered a pair of NOS JBL 2240 woofers, when they arrived, they were packed face to face in one carton. They were destroyed. JJ told me it wasnt there respopnsibility, I would have to file an insurance claim with UPS.

When I called UPS they informed me the shipper has to file the claim. I called JJ back, they told me no, they have no responsibilty. UPS finally got them to file the claim, and I waited two months for my money.

JJ insisted that they packed my woofersd properly, I said NO you did not. JJ was not helpful in any way in my getting my money back. And they were nasty about it too.

And I paid $300 a woofer for these, considering that they are obsolete NLA, thats pretty much full price!

[speakerdave]

Ah, me. More confusion.

I've never had any problem with Jammin' Jersey.

It's Loudspeakers Plus that has not filled my order after four weeks and has not told me what is happening.

I believe you had a bad experience with JJ, Scotty, but when you quote me in connection with a recitation of it, I feel I'm being misconstrued.

David

[scott fitlin]

No, not at all Dave. We all have different opinions of things, places, people, etc!

One person has good things to say about something, another does not.

I used to like JJ for their wide selection of hard to find vintage pro woofers and stuff.

I had a pair of my 2240,s being reconed, and saw them on JJ,s site and decided I wanted spares. They cost me $300ea, + shipping. They shipped them, in one carton, two 18in woofers, face to face, and newspaper as the packing insulation. Both woofers VC,s were punched through the center of cone, one woofers magnet was knocked completely off, and BOTH woofers were totally useless.

When I called JJ, they told me its my problem. UPS told me, NO, the shipper has to file the claim. Who cares? I bought from JJ, and the stuff arrived destroyed, help me out, huh?

Anyway, on the phone with JJ I told them they should have been packed in seperate cartons and shipped individually. They said we pack woofers like that all the time. Sorry, ebay sellers are notorious, the inexperinced ones, for doing this, and it almost certainly guarantess recieving damaged goods. JJ sales rep told me shipping individually is too expensive and they dont have the time to box everything up like that! Imagine that? An Internet store, and Northridge store, that sells across the country via shipping, and they dont have the time to package things the right way?. How much more work and time could it be to use two boxes. I have this saying, it takes the same amount of time to do something right, as it does to do it wrong, so you might as well just do it right! Umm, I paid 300ea, + shipping. Then, I had to ship the woofers back to JJ, and two months later JJ sent me a check for the total. At least I got my money back.

It was JJ,s insistence that it wasnt their responsibilty to do anything that pisssed me off. Their packaging left everything to be desired. And you dont yell at me and tell me I have to get my money back from UPS, I PAID YOU, YOU SENT ME GOODS and YOU are A STORE and it didnt survive the trip!. I sent them my money in good faith. Treat me like a customer you value, and who,s return buisiness you would like to have.

Of course, packed properly, in individual cartons with proper packing materials, the woofers would have arrived in working order. So, it was JJ,s fault that caused the whole thing.