Sure, why not? And anything else 'real' Altec related. I mean I asked for a dedicated forum sometime before this thread since I've been fed up with the Hostboard pretty much from day one, but didn't even get a response IIRC.
GM
Is It better just to pull the horn and mount it on top like it is or does it sound better with it flipped? The bad thing is the crossover control is then down on the corner in the back ,but i guess no biggie once the horn volume is set. Is there added benefit to having the bass horn mid level? what about for HT/HI tho the horn will be over my head when listening?
You're welcome!
Well, you could jury rig something around the horn, but short of properly blocking the entire area off and using slot vents by gapping the horn to the cutout as was the norm on many Altec cabs way back when, best to flop the cabs around and put the horns on top of the mid-bass horn which has the benefit of reducing the distance between the driver's acoustic centers, a big deal in typically acoustically small HIFI/HT room apps where the listening distance is fairly close.
Just packing carpet padding into the flares won't brace them unless you have a way to ~uniformly compact it, so again, better to mass load them with a dense filler.
Yes, it reduces net cab volume (Vb) about 1.25 ft^3 IIRC.
I used two pieces of plywood scrap, but you could make it one piece to fit all the way across, just make a big clearance hole in it to allow the driver to mount to the existing baffle board.
All the older Altec drivers have very loose suspensions (high Vas) to keep efficiency high to make the most of the limited power available from tube systems whereas beginning in the '70s they began trading efficiency for stiffness/power handling to allow increasingly smaller cabs as amp power increased to compensate.
Yeah, that's the advantage of DIY, you don't necessarily have to make any of the manufacturing compromises required to compete in the marketplace, but more importantly, you can make something that fits the needs of your app rather than making do with what's available within your budget and usually for considerably less.
A pair of A7s for the price of a single bare horn........ I need to pay more attention to Craigslist, though historically, 'Hotlantans' are for the most part big on yardsales, etc., so familiar with vintage audio component worth. The last time I saw a great audio deal was back in '75 when I found a '39 Sears Silvertone AM/SW radio, phono furniture console made by RCA sitting curbside in Morningside (an upper middle class locale inside the city limits) awaiting garbage collection.
Into the El Camino it went of course and contacting Sears, found out it had sold for $399 in '39 or about what a year old used Chevy was going for, though adjusting for inflation it 'only' increases to ~$5,837, so not exactly cheap. Still, you get a lot more car, audio performance these days, so maintaining the ratio seems reasonable for comparison's sake. Looks like a year old Impala averages ~$15 k, so to my way of thinking this is the current price point of diminishing returns for a HIFI stereo system.
GM
Ideally, a ~33.2"^2 x 4" deep duct is required for ~32 Hz with sealed off flares, i.e. 828 cab in net Vb. Mounted down at the bottom, using the floor plate as one side of the vent it can be reduced to a simple ~1.15" high slot based on 5/8" thick plywood if I did the math right, so a new one piece vent board to cover all but this full width slot vent is what I'd try first and if it tunes it too low it can always be shortened to raise tuning.
Note that a good seal is required, even a small air hole can ruin a reflex's tuning, so caulk any wiring through holes and/or glue all seams and make sure the removable vent baffle, rear access plate and XO is well gasketed.
Hmm, I took 'loose' to mean high Vas, but you're right; this old, beaten up it could mean a loose, damaged spider.
GM
Again, yes, and if you don't like its looks you can always box it in and cram it full of carpet padding, though filling it with a dense material same as the flares is best overall.
Again, it's mostly about minimizing the driver's acoustic center distance, but you do literally feel more mid-bass/lower mids impact with the woofer at chest/face height and if you sit close enough for the HF horn to be too far off axis vertically for best extreme HF reproduction, you can always tilt it down and still have a closer driver gap than with the horn-in-vent layout.
So relocate it and make a gasketed cover to plug the rear! Altec and many DIYers put them on the front, but I always mount them on the top rear of all the large cabs to make them easily accessible to me, but not 'curious hands', at least not the shorter ones anyway............
GM
GM, Thanks for the comments again 🙂Well My basement is probably 30 ft long and i have the couch probably 12-15 feet away from the cab's so far enough away.I think for now I will leave it in the cab til i get this bracing done etc,See How it sounds and then decide if i want to flip it over and mount horn on top. It's nice now with the wheels on the bottom to move them around on the carpet and my tile floor too where they sit now. Here are some pics of the bracing work I started on tonight will finish it up tomorrow, The cross braces are just 1x4 pine to get the measurments i needed to cut more of the 1 1/2 blocks. Also I have a pic of that foam i was going to use in the flares, which is in the one right now with the non Altec woofer,As u can see it is one solid block that i cut into two different sections for the height of the flare which I had to cut it into smaller strips to get it stuffed in there the higher it went,lol, But After bracing i won't be able to use these I made so i will just fill up the voids with the same foam just cut so it will fit into the voids left after the bracing , I also included a Pic of the back foam i am using so u can see what it is. it is called Mil C foam. Watching the movie last night I was very pleased with the sound where the horns are at sounded very good, mixed well etc. When playing music they sound very good also other then the vibrating so bad ,which i am sure thats the flares and the back of the cab too which i will brace also, probably like u suggested like the new ones with the ribs down the back all the way, will T-nut them to the back so their removable when i need to get at woofer etc.
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$50 😱 Why is it I can't find deals like that ? I can tell you it sure isn't from a lack of trying !
Nice Score ! Welcome to the Wonderful World of Altec Lansing !
BTW ~ As the other good folks have noted, horn needs to go on top with a much smaller port to get the sound I think most people are looking for "I'm sure you are included"! 😉
Nice Score ! Welcome to the Wonderful World of Altec Lansing !
BTW ~ As the other good folks have noted, horn needs to go on top with a much smaller port to get the sound I think most people are looking for "I'm sure you are included"! 😉
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Some more pics of the bracing I finished up on today Just one cab so far, So When I block off the flares, u say its close to 1.25 cf i loose correct? what then is the total cf of the cabinet after that? Forgive my ignorance for abbreviations of cubic feet 🙂. I made a front baffle board that will go right up to the sides of the horn and leaves a gap at the bottom of horn which is 18.5x 1.5 size hole , what would that tune this cab too roughly? Will take pics of that later today after it drys and i put it in there. I still have to glue blocks in there for it to screw too etc, But Want a rough estimate on tuning before i do , If i need to close it down or open it up some...
thanks guys!... Happy New Year!
thanks guys!... Happy New Year!
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When you flip the cabinet over you can also flip the back panel over so your attenuator is at the top? The holes should line up.
I think call means the crossover itself. They should flip just fine. 4 screws.
I'm not for the sealing up of the flares, but that just my experience. Looks like you've got hella bracing in there, should help a lot.
Never seen a definitive volume for that cab. As best I can tell from the plans and from my mesurements, the version with the open flares is about 325 liters, or 11.5 cu. ft.
I'm not for the sealing up of the flares, but that just my experience. Looks like you've got hella bracing in there, should help a lot.
Never seen a definitive volume for that cab. As best I can tell from the plans and from my mesurements, the version with the open flares is about 325 liters, or 11.5 cu. ft.
AFAIK, Altec lists the 825 as 12.65 ft^3 net and using 11.4 ft^3 net in sims yields good correlation of calc'd vent tuning to measured.
AFAIK, I abbr. it correctly.
The vent area/placement you're describing doesn't sound like what I suggested and not the best overall place to put it as I understand it, so don't know other than in a simple reflex with a 5/8" vent length it calc's to ~33.8 Hz.
GM
GM , Thanks, yea This is just a trial thing to try for the vent thing not even sure it will work or sound right . That's why i don't want to glue any blocks to the sides or anything to mount it, My thought was the original port came up and went around the horn mounted in there so i thought if i close it off enough to tune it lower it may work or it may not ,lol.I do like that it will be close to 33 hZ with this hole tho, nothing set in stone yet.Pan I closed up the flares with some 3/4 plywood and screwed it to the top plate it sits in the groove in the bottom easy enough to remove if doesn't sound right. Yea I may have went overboard with the bracing? 😀
I will fire it up tomorrow after the glue sets well for 24 hrs, and see what happens without the port closed off then i will try and close it off with my board and see how it sounds. Some more pics
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Hi Greg, I think I see screws on the back of his no? Mine are held in place with stainless 1/4" flat head machine bolts (I think) with T-nuts and felt tape, same with the 210 cabinets. The backs are reversible so I had assumed the same with his (uh-oh, never assume Cal)
See above.
Yea Mine are not screwed in back there its all glued together as one on the upper half, then the lower section opens up to get at woofer etc., well just the little i have played it right now at low volume it already sounds deeper etc, that's without the front vent board in place,will put that in place tomorrow and see what she sounds like with some volume with and without the board!
HAPPY NEW YEAR!.. Well finished up the Vent board, And I have to say it is a success!!.. Had to turn down most of the lower part of the EQ,Wasn't needed anymore and it sounds great! nice and deep and blows a nice breeze out the port too! The rattles are gone from what I can tell also! Here's some pics of what i did on the vent and the EQ you can see the left channel how I had it before compared to the right now it is considerably lower! for some reason it won't allow me to load pics right now sorry. will try again
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