oface1: welcome!
Good find, you made out like a bandit.
Did you bring them horn in your little white car?
Don't know too much about the Altec large format drivers and horns, so I will leave it up the more knowledgeable members.
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oface1: welcome!
Good find, you made out like a bandit.
Did you bring them horn in your little white car?
Don't know too much about the Altec large format drivers and horns, so I will leave it up the more knowledgeable members.
Hahaha,, no way could those fit in my civic....
I rented a 6x12 box trailer, they did not have a flat one, and it WAS suppose to rain,, but you never can tell.....
It was only about 30 miles away....so no biggie there.....just had to get my truck out , and it likes to drink the gas,,,but I thought it was worth it....
Nice score. You'll love the 817's. They will
sound great in the garage or in a larger room in
a home theater application. I'm not an expert on 291's, but remember them to be somewhat lacking in high freq. response for
home use. Think you can drop in a 299 diaphragm. Check with O.G., Todd, or GM to make sure.
Got to go back and look at the pictures, but those appear to be pretty long throw horns. Ideally, you might want shorter ones in a garage or large room in your house. They will work, but are designed to project much larger distances.
Either way, ............
Your neighbors will love you.......
Good to see you here! I recently got my 291-16B's back from GPA after they converted them to 288-16G's. They will replace missing terminals for $2.50 each, but I would wonder if the missing terminals mean that someone's been in at least that driver.... http://www.hostboard.com/forums/
I would use that one as the test subject. You can carefully take out the screws that hold on the back cover and slip it off. Do this in an area free of any metal debris and keep all ferrous tools clear.
Neither of my 291's had terminals when I bought them, but one of them was also missing a diaphragm when I opened it up. If you have the $$$$ available, then best thing to do is bite the bullet and send them back to GPA for a tune up, and new 'phragms if necessary, especially if conversion to a 288 series is possible. Even just 2 at a time would be worthwhile...IIRC, the 288's are better suited to audio while the 291's are more for sound reinforcement....
Analog,,
I was thinking the same thing about the driver with the missing terminals.....wondering who might have been picking around,,,,
The only story I got on them was that I bought them from the second owner , who was also gonna use them in a project. He had them just sitting around a corner in his hanger/garage/house, and said he did not have anything to push them with. He told me he and his brother got them from a theater somewhere in middle NC.
I believe from what literature I have seen these are from around '83, and the big horns are MR 42a's? and the small ones are MR something else...
If it is possible to convert 2 of the 291-16's to home audio use, I will get a separate pair of smaller horns,, any suggestions?
With the diaphragms in question, you are saying to get the replacement diaphragms for the 288's then? I would like to use these in a home audio/theater set-up, at least 2 of them. How challenging is the replacement process? I noticed that the 288's spec's are almost identical to the 291's, only the 288's seem to go a bit higher..
Also will be looking into a pair of tweets for them, the 288's go up too 15k right?
Will have to save some $$$ but I think I will get at least a pair going by this time next month or at least try. I will have to keep them out in the garage, I doubt I have a room big enough in the house to place the 817 cabs in.
Just still wondering if the 921-8a woofer is cut out for at least decent audio reproduction.... or will I need to start looking elsewhere?
Ahh, a lot of what ifs to and looking forward to getting answers or finding out myself.
later
Nice score on the goodies. I think you should mount that long horn on the top of your Civic. Less trouble in traffic.
Yeah,, my civic has a squeeky sounding horn , I swear my old bicycle had a louder horn than this car...
But I have noticed here in SC, most people in their big suv's and trucks try to run me over while I am in the civic, but the story is much different when I am driving in my Nissan Armada ...
I had a pair of mine shipped to GPA, a broken mounting bolt replaced, new diaphragms installed, a magnet check with free remag if necessary, a sweep check for function, 4 new terminals installed, and shipped back to me for less than $300 total. I do need to e-mail Steve for a copy of the paperwork for my own records, but GPA service will restore your drivers back to factory spec or better(depending uopn the 'phragms installed) and may actually increase the resale value if you ever have to liquidate. A definite win-win deal.... http://www.hostboard.com/forums/
Congratulations on your acquisitions.This set up will make a lot of DIY set up look like transistor radio.
I would make it a 3 way TRI AMP the bottom part
from 20 to 250 second half 250 to 500 and horn
500 to 20kHz.
Can be used for rock group and you will get a lot of SPL Dynamic range out of it.
This sort of set up for small night club is the Ideal thing.
...................
<font color="#FFFFFF" size="1">[ May 06, 2008 08:08 PM: Message edited by: CONVERGENCE ]</font>
I just checked the GPA site...
http://www.greatplainsaudio.com/PartsList.html
and the 23834 diaphragm for the 288-16G will fit on the 291-16K, so you're in business.
Call Steve or Bill at GPA and tell them the Altec board sent you... http://www.hostboard.com/forums/
<font size="2" face="Verdana, Helvetica, sans-serif">Hear, hear! Done this way, it will give the phrase "you will rock!" a whole new meaning.Quote:
Originally posted by CONVERGENCE:
Congratulations on your acquisitions.This set up will make a lot of DIY set up look like transistors radio.
I would make it a 3 way BI AMP the bottom part
from 20 to 250 second half 250 to 500 and horn
500 to 20kHz.
Can be used for rock group and you will get a lot of SPL Dynamic range out of it.
This sort of set up for small night club is the Ideal thing.
...................
That is exactly what I did in 1975, but I made mine a true 3-way tri-amp with an amp for each driver. I used a DeCoursey(he is long gone) active crossover at 800Hz and 7KHz. I used 2 Altec 414 12" woofers, 806 driver/811 horn, and an EV T350 super-tweeter. Sounds great even without the sophisticated instrumentation available today.
IMO, the entry fee you paid plus the gas was a good price for just the four horn drivers, even if non-working.
Consider the horns and four loaded 817 boxes as a substantial free bonus. http://www.hostboard.com/forums/
<font size="2" face="Verdana, Helvetica, sans-serif">Well to be honest ,, I was grinning like a dog eating cat s*** after I loaded it all up and headed back home which was rough for 2 people, had a appliance dolly , but it do not work so well with their small tires in the sand soil here till I got home to my driver way and hand a old navy buddy to help,,,,Quote:
IMO, the entry fee you paid plus the gas was a good price for just the four horn drivers, even if non-working.
Consider the horns and four loaded 817 boxes as a substantial free bonus. [Thumbs up]
I think I might have used maybe a 1/4 tank of gas,,,,so every thing came out under with trailer,gas,lunch and time included, $500,, not to bad I am guessing....
might have to get a hold of bill , I have seen that it is best to call him, and when that time comes I will...
Is there a walk through on replacing the diaphragms if needed?
thanks again all
Just saying hello to all, and that I just have had some new acquisitions of late.
Just to fore warn ya'll that this isn't a post about asking how much is my new stuff so that I can go flip it.. Might be a little long as well
here's the link to the pics, not sure if I am allowed to do that here or not.
The AA's High Efficiency forum
As you can see I came across some Altec MI stuff, I did not open up the 817's and see what driver they had, but I have seen through some searching that this might be the best choice for hi-fi reproduction. Is this true or is it a matter of preference?
I am going to be using these in a large (20'30') dedicated listening/HT area and would like to know if these could be used in that manner....
I mainly listen to music and have mainly tube amplification ,sets,and various other pp and an old pioneer SS receiver.
Also I need to check the diaphragms and make sure they are ok, how do I go about doing this? Will I need a torque wrench to tighten them down? I am diy-er and like to learn new things,,so I will be up too the challenge...
One of the 291-16k's is missing both positive and negative leads on it, is there a re fix for this? or am I'm screwed?
I plan on taking my time with this , since I haven't even cleared the ground for the new addition yet, so these will be set up in my garage , which is about 25'x25' in size,, I plan on only using 2 of the 817's cabs..
I look forward to any advice, experience and ideas you may like to share,, and If I am allowed I will post pics on my continued progress
Thanks,,,,
Well, could not find the edit button,,but I also meant to ask about building a xover/ or I am thinking about going with the behringer 2496? if that is it,, not sure,,
Thanks again
I saw your post on AA, quite the "loot", congrats. I'll leave the suggestions to the more knowledgeable, but do post your progress.
Dave
Essentially you have 3 diaphragm choices...
291- high power attenuated highs...stock unit, no longer made but available on ebay. Aluminum dome/mylar edge. Technolgy of the 70's
288- AFAIK GPA is only making one 288 fram in different impedances. The 288 is moderate power, good highs. An extra octave extension over the 291.
299...derivative of the 288, different aluminum alloy, high temp carbon fiber former. High power good highs, If you wanna play loud in a big room, consider these. newer technology than 291.
I have heard a zillion times the 288 and 299 frams test exactly the same...to my ears, which have made me a lot of money, the 288 has SLIGHTLY better highs. I don't want to open an argument on this, just point out where fact and opinion diverge.
If you are handy, replacing the frams you self isn't hard. You don't have alnicos right? So they won't need remagged.
GPA has a download with instructions on replacing frams.
Frams wire and terminals maybe 30 minutes a driver.
O G,
I like to consider myself handy and capable, so it looks like I will convert them into 288's then.....right now these 291's are 16ohm,, does it matter if I get 8 or 16 ohm fram versions then? they not alnico, so no re-magging for me
I will look on the GOA site for instructions... Thanks bowtie for the link....
gonna go do some reading now
btw I found the edit function here finally ,lol
O G
Went to the lansing heritage site and downloaded all the tech specs that apply to all the drivers, cabs and the horns, also copied the info on the T/S spec and xfered them to my own excel spreadsheet for future reference ....
I read about being careful with screwdrivers.... i guess i could use a non- magnetic one I guess, or tweaker? I am going to be looking at them all here in a bit.
A quesiton on measuring DCR, they say 16 ohms, I really doubt if they will read that high after all this time? what is the margin -/+ they should be reading,,,, I have seen 8 ohm speakers read around 6-8 ohms and still be fine..
I have still hooked these up for fear of damaging them..... I need to make a xover in the short term,, any suggestions?
gotta go ..
later
Here you are, my friend. Babble fish should help -- unless you already know French.
http://monsite.wanadoo.fr/acoustique...in/index.jhtml
I have used 416B loaded 817s under EV9040/288Hs and loved the combo. Please let us know what woofers came in the 817s.
For crossover duty, btw, you cannot beat the Behringer digital gear for value.
Congrats!!
<font size="2" face="Verdana, Helvetica, sans-serif">We need to go to Sound 101 here...Quote:
Originally posted by oface1:
O G
A question on measuring DCR, they say 16 ohms, I really doubt if they will read that high after all this time? what is the margin -/+ they should be reading,,,, I have seen 8 ohm speakers read around 6-8 ohms and still be fine..
Lots of people confuse DC resistance and inpeadance- they ain't the same.
The resistance of the speaker really does not change much throughout its life- those 8 ohm speakers were 6 ohms when they were new.
Impedance is always higher than DCR. 16 ohm units often read 12 ohms.
Impedance takes in a number of factors.
For instance, I play with bass horns. It is not uncommon for an 8 ohm speaker to go up to 10-12 ohms impedance in the horn..this is due to the loading the horn places on the unit.
Impedance is quoted as a "nominal" figure and varies with frequency. It helps to have the "curve" showing these changes when designing a passive crossover.
For instance- a diver that is 8 ohms at 800 Hz may be 9.2 ohms at 1200- if you wanna cross at 1200 take into account the 9.2 figure if you want to be exact...
The beauty of active xovers is all these calculations go out the window...The Behringer DCX 2496 is the best bargain in cheap crossovers IMHO.
There are European guys modding the outs of the Behringers to make them friendlier to home use..I wouldn't bother.
If you just want crossovers short term, basic SR units will at least get them up to listen to..
A "textbook" unit just assumes 8 ohm impedance and goes from there...not fine tuned to the speaker or box.
There are some decent textbook units to be had cheap, but for long term home use, custom or active is the way to go.
O G ,,
Thanks for the insight, I should know better , but were never really measured speakers in the navy,, I just looked at o-scopes and analyzed equipment and tweak stuff away....,,
David , the drivers are 921-8a's .... I have read a bit here and there that some say they are good for clubs/venues, but I might not enjoy them for home use....any experience with these drivers?
<font size="2" face="Verdana, Helvetica, sans-serif">Not sure I see the benefit in rolling off the bass in the upper cabs...Quote:
Originally posted by CONVERGENCE:
I would make it a 3 way TRI AMP the bottom part
from 20 to 250 second half 250 to 500 and horn
500 to 20kHz.
I would run all the bottoms down to their lower limit...and start rolling the mids out of the lower set an octave or so below where I crossed to the horn...
The reason for rolling the mids out of the bottom cabs is to create a smoother transition in sonic image at xover.
Your mileage may vary.
The 921 is an updated 421. Used tons of them in the 70's.
Good strong mid-bass. Louder than stink.
They don't go as low as say, 416's.
I would consider a set of subs with 3184's as the easiest way out if you wanna keep it all Altec.
A user here was lucky enough to get a set- just search the board, it was recent.
with subs you don't have to apologize for anything.
Kinda hard to get from down around 20 all the way up to mid bass with one unit...
You could gain a little with different 15's in the 817's, but the 817 is basically a mid bass box. the original intent of this stuff was to punch the sound thru a screen to the back of a theater, remember...
8 or 16 ohm frams interchange , magnets are the same.
So NP if you want 8 ohm drivers...
Mainly be careful with the screwdriver when replacing frams- in the beginning I would recommend holding the tip of the screwdriver and guiding it onto the screw then transferring grip to handle- that's the chief hazard is the mag yanking the driver in a direction you didn't plan on...
I changed my first diaphragm at age 18 without instructions, but I always scored well on the mechanical ability charts...sounds like you are the same, doubt you will have problems. It ain't rocket science... http://www.hostboard.com/forums/
Hello,
I don't have any experience with the 921's, but judging by the specs, it looks like it would not go as deep as a 416 but could handle considerably more power. If you are contemplating a sub woofer anyway, try them and see for yourself -- they have a very low Qts with a highish res. frequency( .25 and ~ 35 Hz according to my literature) so they could be excellent upper bass/mid drivers.
If you haven't done so already, download WinIsd and play with the box size and tuning to simulate the response of your 921 loaded 817s.
Well finally rechecked and opened all the drivers up. the one that wasn't giving any readings, continuity and ohms had a bad diaphragm.
I am guessing whoever had this one last replaced the diaphragm wrong with the leads crossed (L1-red/ L2-blk), which was there was a caution in the instructions that someone posted a link to (thanks).
I will, in the future, order some 288 phrams to have a pair of those in order to compare to the 291's. In the meantime I wondering about going about maybe building a xover for the current setup I have now.
I am gonna use the drivers I have now currently to try and get up and running now when I build a xover( MR 64),driver(291-16k), and (4 each side) mid-bass driver (291-8a)in 817a cabs. The reference material says that the 921-16's can go down to 500hz, the 921-8a's can go up to 3.5khz. Is there a simple xover to build for this?
Right now my funds are a bit limited and I think for the time being the dcx2496 is out of my reach. Anyone have a suggestion for a type of xover to get me going till I can afford the dcx? Would it be cheaper for me for me to build one now or just suffer and wait to save for the dcx? Would build a xover be cost effective for now?
I am able to sling solder and troubleshoot.So i look forward to building.I just want to get some sounds going for now and see how this set up sounds. I promise to post pics along the way and I am up too any amount of criticism and suggestions that comes along the way.
thanks.....
Do you want a recommendation on a cheaper used active unit? Lots of Pro sound xovers get retired to home use.
Or do you want to build something?
Martin has input plates and boards, plus caps and inductors. Site has a calculator for "textbook" crossovers.
http://www.martinsoundpro.com/item.asp?id=322
A cheap recommendation would be nice, but I am not afraid to build either. Which one would do less damage to my wallet?
If I was to build a xover, what type do you suggest? I saw there was 1st,2nd,3rd, and 4th order xovers. I guess I need to study up on this.
<font color="#FFFFFF" size="1">[ May 22, 2008 03:19 AM: Message edited by: oface1 ]</font>
There are used pro sound actives to be had from $50 or so up. Just depends on who offers what this week.
There are literally tons-. Rane and Ashly are generally decent as are many others. There are new Behringer units starting about $75, but better is over $100. But the at $199 for the DCX, as posted in another thread, I'd think twice before spending $125 on a unit.
If you see something rum it by the folks here. Between all of us we've used lot of units.
If you can use a basic passive crossover tutorial, go here:
http://www.passivecrossovers.com/
Written for car stereo, but the technology is the same.
Second order is most common BTW. Again it just depends on what you are looking for- you may have a better idea after reading that tutorial.
Hope some of this helps, if not please keep asking.
OG,
Thanks for the info,, and I will be posting a lot more questions/ pics in the next few weeks/ months...
later....
<font color="#FFFFFF" size="1">[ May 22, 2008 11:41 AM: Message edited by: oface1 ]</font>
I tried to go to the Altec pro site when I first got these speakers, and to no avail it did not work , no matter what browser and version I used , so I suspected I was out of luck.
Well I saw a post recently that linked directly to it , I think it was one of the posts in the MR horn post. I went to it and saw that it worked, and found the xover networks.
What would be a nice xover point for the 921-8a's, since the pdf says it goes go up to 3.5khz and the pdf for the 921-16k's with the MR64 horn says recommended @ 800hz....
Looks like the N500F network would work, but Is it the same as the schematic of the N500G? If so I could just replicate that and would that be cool?
I doubt I would have to use any $$$ unobtanium caps,resistors and inductors for parts would I ?
Thanks
The 921-8A is, for all practical purposes, the same as the 421-8A. They were made for higher power applications than the 416's and 515's and aren't quite as smooth.
As with all bass horns, the 817's don't go all that far down at the low end. We have a pair of 816 cabinets with MRII594 horns and 299-8A drivers (horns mounted inside, grille cloth on the front), and had two cabinets built that are the same size as the 816's, but with 2-18" Peavey subwoofers in them. When you stack the 816's on top of the subs, the height is about right for a small venue; put them on one section of scaffolding and the height is about right for a larger one. These are probably the best-sounding speakers we own! We also have 817's and larger manta-ray horns that we still use occasionally for rentals, and we have a couple of custom-built dual 18" subs we use with that setup. Everything is actively crossed over.
Dave Edmonds
Dave Edmonds
Hey oface1
I will be the last one to give you any tech support. In fact, a few months ago, O G recommended me to read that site as well. To make it short, I built my passive crossover from the scratch. It was fun. But it wasn't cheap. If you are thinking about your wallet, a $50-$100 active crossover is hard to beat. If you have all the parts necessary in your hands, then it's a different story.
Tim
tim,
What did you spend on building yours?
What is your set-up like?
Yeah I am thinking I might just go to easy route and look for a active xover.
Hi Ya
My set up is 414-16b/811. And I copied 800nf crossover which is a two way/second order. I budgeted the whole project for $50ish. Boy, I was way off! I ended up spending well over $100. For example, I needed 4 inductors. I spent $50 plus for those, alone. At one point, I thought about winding my own inductors. But it was way over my head. But take a look at some of the inductor values you need here. Plus, shipping, etc. It will give you some ideas.
http://www.partsexpress.com/mfg/jant...en.cfm#15gauge
If you can get a used active for $50-$100, and I think you can, that's a bargain.
Tim
And did I tell you? I did not get it right the first time around. So I had to reorder, etc. So, it I add those up.... I call it a tuition. http://www.hostboard.com/forums/