Cabinets for Altec 515B woofers suggestions

[Leland]

There is this guy on ebay that has a low frequency Altec cabinet.....Perhaps to get the ideas flowing.

[URL="http://cgi.ebay.com/ALTEC-LANSING-817A-Horn-Loaded-LF-Speaker-Cabinet-Empty_W0QQitemZ220543427424QQcmdZViewItemQQptZLH_D efaultDomain_0?hash=item335969a360[/URL]

I don't know what the Altec group here thinks of the "folded horn" design. But I believe Altec did use it for some speakers.

The La Scalas are by anyone's idea large speakers....but they are substantialy smaller than the Voice of the Theater....which is what you were talking about in your OP. And mine have great clean punch-y bass.

[gearfreak]

mentioned sooner, and I'd have pointed out the 4 peavey FH-2's that were up near Allentown the other week with a full project 2 compliment for $650!. Worth the van rental and drive to save the carpentry! May still be there... Per the OT, may have trouble cramming 515's in them though, dims would need to be checked.

[Mustang Marvin]

I have a couple of corner horns I am considering as a DIY project The Altec version is beautiful, but I am really leaning tward the Jensen version. I bet the 515 would fit nicely.
I would prefer the 416 though.
Jensen Technical Bulletin No. 3

[Mustang Marvin]

Here is the Altec version...
Altec Lansing - Page 31 - diyAudio

[GM]

Hmm, maybe with enough EQ, but every Jensen driver I've measured or seen measured specs of indicates that none of the VOTT woofers is even close to being suitable. Only one way to know for sure though.........

GM

[MrMonster]

Hello Lads, and thanks for all of the input.
From reading these posts, most of you are well versed in speaker design and I appreciate learning from the posts.

So, am I correct in my idea of a front loaded cabinet of 11 cubic feet with a tuned port below the driver, I think I have seen some photos of a current Hiagra design that uses a tall front loaded cabinet with the 515B and a rectangular port.
but can't find that photo.

After thinking this through, I might not be married to the 515B's, but do want the 288C horn. is there a LF driver in cabinet that would marry well with the 288c?

Thanks,

[GM]

But I can inform you that my La Scalas have terrific bass and are much smaller than the A7.

Perhaps you could look at some La Scala speakers and see what you think. I guarentee you will be happy with the bass they produce.

Hmm, not to disparage the LS's performance or your opinion of it, but the physics of the situation dictates it's more like mid-bass unless corner loaded in a relatively small room and why djk came up with converting the mid horn's cavity into a reflex to extend its response. Even this apparently falls somewhat short since I've helped folks who've done this mod and still dissatisfied.

For sure, its mid-bass is considerably better/more extended than the A7's but falls short by the same amount (and maybe then some) when compared to its 'sweet' BW, so comparing these two are an apples n' oranges one overall since each is optimized for different BWs.

All that said, I'm still not clear on how extended a bass response Donald wants since he claims that with a "full open bottom port" (which unloads around 80 Hz IIRC, i.e. the beginning of the mid-bass BW) "They sound very good now, with good clean Bass." If this is the goal, then the LS is a good option if his horns go low enough to XO to it, which so far my assumption has been that they probably don't.

If by "full open bottom port" he means the stock port as shown in his picture, then tuning is around 55 Hz, so the LS with djk's modification may suffice.

Plus he mentions having "256's with Jabo conical horns" which I'm not familiar with, though conic implies they won't load anywhere near low enough to mate to the LS unless they have a much larger 'footprint' than the A7 and his picture shows what seems to be 311-60s, so until we know what all the particulars are we're just 'shooting the breeze'.

GM

[GM]

Hello Lads, and thanks for all of the input.

Greets!

You're welcome!

Oops! I didn't see your response before responding to Leland's. I list some needed clarifications plus I forgot to include what amp you're using as it affects box size, tuning choices.

If you want real bass and the amp's output impedance isn't too high, then ~11 ft^3 loaded with an original or GPA 416-8C is big enough to have solid output all the way down to Fs if desired. The 515B in theory will have a bit more high SQ mids at the expense of a more rolled off LF response, though some EQ to trade a bit of its extra HF efficiency for LF gain BW can balance it out, so being a four+ decades long 515B user this would be my choice.

GM

[MrMonster]

Hello Lads
I did forget to say that I got a better bass response by stuffing the flares full of foam sheets, and lined the reflex box below and inside the back with 3 inch thick fiberglass insulation. I also experimented with the vents by using a sheet of 1/2 inch thick foam board and trying different vent. The best was the two vertical vents as seen on the A7 cabinet.

The Jabo horns gave me a better sound that 903, 805, or 311 horns.
hI have tried for days to load a photo, but I keep getting a message of exceeding my limit, but when I try to delete old attachments I get a internal server error when I try to edit on any of my details.

Thanks

[valhallax]

mr monster... if its worth anything, i have a devil of a time loading photos as well, the old hostboard was very easy to use. now it seems very difficult to me as well..even tho ive alot of pics to post