Hoffman Amplifiers Tube Amplifier Forum
Other Stuff => Cabinets-Speakers => Topic started by: heresrobert on May 19, 2012, 06:04:13 pm
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:w2:
I took apart two old speaker cabinets that are really big and I don't have room to keep. The cabs were veneer over particle board. In each cabinet was a tweeter horn, twelve Helaton 5" speakers and two of these pictured. The 10" speakers are dated 19 Jan 1962. The cone is ribbed and is about 2 3/8" deep. Anybody know about them or where I can get the foam rings? I don't want to dump a lot of money into them. If I can make them sound decent, I'll be happy.
Thanks for any help.
Robert
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Heco is a German company mainly dealing with hifi speakers. Their drivers are quite good, some are excellent, but not for guitar or MI applications of course.
You may refoam them using one of the many available kits. I guess that a FSK-10F or equivalent, designed for roughly equivalent 10" Advent mid/woofs should be OK, but you should check the measurements - Heco uses metric baskets and everything. Maybe one of the specialized (r)etailers could help you here, check for instance Simply Speakers http://www.simplyspeakers.com/ (http://www.simplyspeakers.com/) or Orange County Speaker http://www.speakerrepair.com/. (http://www.speakerrepair.com/.)
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> Advent mid/woofs should be OK
I see a paper surround, not the foam on Advent.
I think Robert's foam-rot is just to seal against the baffle. Hardware store weatherstripping might work.
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Hmmm. You're right.
(Note to self: get new glasses)
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PRR and FYL,
Thanks for your help. I appreciate it! I had thought about the weather stripping idea. I'll give that a try on one of the speakers. As FYL pointed out, these are (old) hi-fi speakers, so the sound might not be best for guitar, but its worth a try.
Robert
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> these are (old) hi-fi speakers, so the sound might not be best for guitar
Very worth a try.
IMHO, these are not modern "hi-fi" speakers. They are old-time radio speakers, assorted to cover a wider range. The Ten has good bass but gets erratic and beamy above 1KHz (especially in a pair). The Fives are sweet above 200Hz to 2KHz and a bit beamy to 5KHz; a dozen(!) offer pattern control (column, siren, semi-hemi?) but no 10KHz-20KHz top octave. The horn does that. The result covers ~~60Hz-15+KHz more or less well, and looks VERY impressive. Might be very lush. Could be plenty loud all across the audio band. Surely isn't as smooth or flat or coherent as many other hi-fi speakers.
Anyway, I see nothing to damp the high-end of the Ten. It surely sings well up the guitar band, though like any Ten it gets beamy on the overtones of the guitar top octave. The paper and corrugations are similar to many popular guitar speakers.
When a speaker is For-Guitar they may stiffen the suspension to support the bottom note and juice the apex for screaming highs. So it may not compete with a For-Guitar speaker. OTOH the bass can be brought up in a small sealed box (try 1 cubic foot) and maybe you don't need screaming highs. (Might be good on an "icepick amp".)
The pile of Fives is also interesting. 2 Fives with a few Watts of good tube power would be a fine parlor amp. 8 Fives in a mini full-stack (or 24 as a triple full-stack!) might be a fun "backyard stadium" system. My instinct says, for guitar, to trim off the wizzer cones; guitar does not want much over 5KHz. However try one with/with-out before you trim them all.
Home-priced tweeter horns from 1960 should be smashed and trashed. There were excellent high-horns back into the 1930s in movie sound, and a few more serious monitors, but not in domestic systems.
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PRR,
Thank you. There's a lot to consider with all of your thoughts. I'll try the 10" in a cube. That should be easy enough to build. Heck! I'll make two cubes. I'll also give eight 5" mini stack a try.
Thank you again.
Robert
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http://ratch-h.com/arraywiring.html (http://ratch-h.com/arraywiring.html) is a nice link to wiring multiple speakers together. You can get a useable impedance out of almost anything... use a cheap meter to measure the DC resistance and guesstimate up for the AC impedance (ie 3,12 is usually 4 ohms, 5.5-6 is usually 8 ohms 12 is about 16 ohms.) That will get you in the ballpark. (what PRR said about the horn tweeters- ear-itating)! You can make stacks that are 6-8 drivers high and loud as you need. Make the lines single driers one above the other- eliminates combing effects. If you must do a 2-wide stack/line, angle the speakers inwards (not outwards) at 15-20 degrees to eliminate beaming effects. Don't worry about box volume- the midrange's Vas won't care a whit. stuff lightly with craft store pillow stuffing or the Wal-mart eggshell pillow topping... if you have it to spare. Then make noise, and have fun!