Depends on room loading and how tonally balanced [~flat] you want its response without resorting to mass quantities of contouring EQ: http://www.lansingheritage.org/image...515g/page3.jpg
Notice the LF horn is completely unloaded by ~110 Hz........ Tuning the vent lower will keep the driver from unloading down to that point and will typically blend better to the room, but ideally a sub system capable of blending to the LF horn's gain BW is the goal.
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
You can also use EQ.
But build a spacer to move the woof back from the cab. Otherwise the cone will hit. Ask me how I know.
Simple with 1/4" ply and a sabre saw.
A7's will go low with EQ.
Otherwise add subs.
Here is a great one!
http://www.altecpro.com/pdfs/vintage...%20Speaker.pdf
I can't find the PDF for the system.
Ron
Enjoying Altec Speakers since 1972
Try these. It is at the bottom of the PDF :2thumbsup:Originally Posted by RonSSS
http://alteclansingunofficial.nlenet...osurePlans.pdf
http://www.lansingheritage.org/image...pro/page08.jpg
http://www.altecpro.com/pdfs/vintage...%20Systems.pdf
I plugged that speaker into an online calcuator and with its suggested box size of 4 cu ft, the frequency responce nosedived at 50Hz and was off of the chart at 30Hz. Increasing the enclosure to 12 cu ft, but not knowing the vent size and just guessing, there was a faster initial drop, and then a rise, but it still dropped off of a cliff by 30Hz. I would have hoped for better. How much is that woofer anyway, I can't find the price anywhere.
I have been equalizing thus w/ 8-3" piezo super tweeters per speaker;
--25Hz---40--63--100--164--250--400--630--1KHz--1.6--2.5--4--6.3--10---16
+12db __+12__0__-3___-3___-3___-3___-3___-3____-3__-3__-3_-3__+10_+10
Right, for typical prosound apps back then and still to a great extent today in touring sound, 60 Hz was/is the lower useful limit with 40 Hz being typically at least -24 dB, so its seeming too small vent for its rated power is more than adequate.
For HIFI/HT apps, tuning 12 ft^3 to Fs to as low as 17 Hz should be fine combined with some room/boundary gain and maybe some EQ, though it takes two of these to match up to a single A7's mid-bass horn's sensitivity.
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
When I bought my 16-3" piezo super tweeters from Radio Shack long ago, they came with no data or wiring instructions. The only thing I knew was that ohms were halved in parallel and doubled in series, so I wired up 4 in parallel to 4 in series. I know realize that their resistance is something like 1000 ohms and no worries in that regard. I have been reading this thread on piezo tweeters indicating that I need resistors to protect the amp from high frequency feedback. Can anyone dumb this thread down so that I can duplicate what they are talking about? I don’t need an L-pad, just a wiring diagram in plain English. My only wiring experience is with using plumbing solder and a Bic lighter.
http://www.audiokarma.org/forums/showthread.php?t=79659 Specifically post #30 with it’s thumbnail image and on. (edit; opps, I guess I forgot about the wiring diagram in post #32. So I don't need the 8ohm reisitor, just the 20-50 ohm resistors in series before each tweeter.)
Thanks a bunch
How dumb would it be mounting 7 of these things in a 12” globe or basket ball centered over the horn and woofer voice coils?
Last edited by VolvoHeretic; June 3rd, 2011 at 11:34 PM.
How about this for the encloser sound deadening reenforcing? The interior 1/2" sound board is sandwiched inbetween the A7 plywood and 3/4" MDF, bolted together with a rubber washer assembly to totaly isolate the two. I would still use single plane forming plywood on the outside of the curved horn bell with the same technique to reinforce the curved bell since there is no room to add any solid piece of wood to the inside of the bell. ???
Last edited by VolvoHeretic; June 4th, 2011 at 02:32 AM.
In theory, pretty dumb. Comb filtering and who knows what else. But a lot of stuff like that is not as bad in practice as it might seem. Multi-cell horns, for example. I'd try it and see. Might be cool.
Bose had done some wedges (1/8 of a globe) with 20 some drivers, ca early/mid 60's iirc. There was recent discussion of them somewhere.
Came across as I was researching these, which were hangable (upside down, we assume), apparently if one wanted to :
Design Acoustics D-12 - Audiokarma.org Photo Gallery
Antithesis of horns of course.
Posting Permissions
Bookmarks