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I'm parting together a set of A7 speakers. So far I've acquired a set of A7 cabinets, 416-8A woofers, 511B horns, and 902-8T drivers. All I need now is crossovers. I'm leaning toward 800Hz. Along with stock Altec crossovers, I see there are designs by others. So far I have a copy of Thunder Bob's and The Ultra Fi Times magazine #6 crossover designs. The post below is talking about Sound Practices article and Jean Hiragas design which I have no information on. I read that the Altec stock crossovers are not that good for home application and some are not sure about Thunder Bob's. Can I get some recommendations for best crossover? Thank you.
Follow Ups:
I recently bought a pair of A7s with 416, 511 and 808 drivers that were missing their x-overs. Not wanting to risk any money on ebay, I built an XO using whatever odd&ends I could find in the spare parts bin.
After much listening with various configurations, 2nd at 500hz, 1st at 800, 1000, and 1200, I settled with a first order XO at 1500hz. Using Solen components, a 1mh inductor to the woofer, with 11mfd on the horn gives me the least congested, most dynamic, effortless music reproduction of the many XOs I tried. That being said, a proper Altec XO may just completely bowl me over!
Cheers
The 902 would work better with a slightly higher frequency than 500 hz. The 802 works well to 500 hz, the 902 less optimal at the lower frequency.
The only Hiraga design I have seen was for the A5 not the A7. As I understand it, the basic idea was to use the extra efficiency of the driver for EQ rather than just padding it down to match the woofer. A similar Altec design for the parts you are using would be either the N501-8B or the 1285-8B. The 1285 will allow you to try all three common XO points. The 501-8B is simpler and probably easy to build yourself. You can find a schematic at the link below but be sure to read the whole thread before you invest in parts if you decide to go that route.
The best Altec crossover I've heard is that from the Model Nineteen. It incorporates EQ which gives a more extended high end response than any previous Altecs.The rub is that it crosses at 1200 hz rather than the 500 or 800 of earlier Altecs, this provided a dispersion match at the crossover point and higher power handling too.
My experience with the Nineteens has been so good that I now advise anyone who is going to do an Altec rig to do a Nineteen, it's the best all-in-one-box, turnkey speaker they, (thus anybody) ever made. My opinion.
Plans for the crossover can be found online, so can plans for the box.
Tom -You're not starting to believe all that propaganda about matching up the woofer & horn's radiation patterns in the crossover region - are you??
Say it ain't so!
;-)
I reckon I can take it or leave it Duke. It can't hurt if it doesn't get in the way of other things, like clarity. IMO the main advantages though of the Nineteen over previous Altecs are the extended bass and highs.Maybe I'd like the speaker even better if it crossed lower like earlier Altecs but I ain't a'worryin' about it, I'm just taking the package as it was built in 1976 and going with it.
I've been using an active crossover with my 416a's, 806a's and 811b's.We tried 800hz but preferred 1200hz for the reasons given in the other posts. With a different compression driver the results of course would be different.
I tried initially to do a passive crossover but gave up due to the lack of test equipment and experience with the design.
The active was much simpler to implement.
hey Tommy - hae you hezrd teh EQ used with Altec Duplex? - just curiousFreddy
ps here's Markwarts pages on 19 and coaxial
Freddy---I've often considered building Jeff's crossovers for the 605s but never did, nor have I heard them.Now with the Nineteens I'm done for awhile. I'm gonna sell off my A7s and 605s and relax with the Nineteens.
I'm so satisfied with my Nineteens that I don't even think about replacing them. For me now it's all about getting the best sound out of them that I can. I know they are up to any electronics I could provide for them. Now it is all about source, room acoustics, keeping clean and tight connections, and good Kentucky bourbon.
my rig is kinda like the 19, but i have 414's (the 12" little bro of the 416..), and they really didn't shine until i shifted my crossover up from about 1000 to 1500.. granted-- i'm NOT using an altec horn driver or horn. but there's really something to be said for letting an older altec woof run a little looser-- i dunno if you're up into breakup with a 416-- i know I'M safe-- but in my experience, all those altecs'd run up to 2-3k without major problems.. i've only lived with the 414. whether its better matched dispersion between my drivers/horn, or just a more amenable place in FR for my drivers, i dunno.. but they both seem to like it too!
i also like old oil caps, and a mellower sound with a WAY less in-your-face presentation.. so take these things as part of any decision you make!
good luck!
Tom,I've decided to buy some Altec N1285-8A or B model crossovers to start out with. That way I'll have the choice of 500. 800. or 1200 Hz. Probably do some home builds later. Do you recommend me building some nineteen cabinets to replace the A7 for home use. Can I use the components I already have with the 1200 Hz setting on the crossovers for the nineteens? Be great if I could call you to educate me.
SB---Does that crossover have the high frequency EQ? If so I think they'd be very good, the EQ is very important and IMO the main reason the Nineteen trumps earlier Altecs.Yes, you can use your components with a 1200hz crossover.
And yes, knowing what I know now I would go with a Model Nineteen type cabinet over an A7 type, the improvement in bass depth is substantial and the cabinet is smaller to boot.
Over on the unofficial Altec forum you'll find much information and discussion on DIY Nineteen cabinets and varients of the Nineteen cabinet, there are some very astute Altechies over there such as GM, Old Guy, RonSS and others.
Thank you Tom. I really appreciate your time and information. I'll start doing some research over at the unofficial Altec forum on the Nineteen in plains to build some. First I'll give the A7 cabinets some listening time for comparison. The crossovers I'm looking to buy are the N1285-8A or B models. They have a pot adjustment for the high frequency and mid frequency when you push a button and adjust the pot. I do not have enough knowledge at this point to know what the Nineteen high frequency EQ crossover is you're referring to. What is it?
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