need help with altec 515 (mid)basshorn....
hi everybody, maybe somebody is willing to help me!
right now i listen to a scaled down version of the living voice air partner.
(if somebody is interrested in the dimensions, sorry, i promised to the guy who helped me years ago not to publish it. please dont even ask)
bassdriver vitavox mm300, 12".
midrange vitavox s2 with rh330.
treble jbl 2405.
source:buff III, s&b tx103 transformer, choke loaded 5842, diyhihisupply 300b, lady day(310-300b)
no phono at the moment, working on the dac and needed the stepup.
room is small, 3,5m x 5m x 2,5m.
ft:10 x 16,5 x 6,5.
one thing:never trust somebody who says you cant listen to a horn like this nearfield, its sounds wonderfull!(3m, 10´away).
i´m quite shure it would sound better in a larger room, but even in my listenining room it is fantastic!
you may wonder why i would change the bass horn:
got 2 gpa 8hp woofers for a very good price and searched the web and of course this forum.
515 midrange should be very good.
my horn is folded, a straight one like the exemplar horn could be better at higher frequency?
listening mainly to acoustic blues and jazz, sometimes 70s rock.
something like the exemplar would bring the rh330 down 6-7", would be good i think because i am listening that close. the rh330 would be on ear-height and this sounds definitly better in my room.
the horn should go down to around 40-50hz, low enough in my room. i have 2 m&k 5000 subs, but they are not connected, dont integrate well.
tried the subs with active xover and software, did not like it.
(btw, i dont like to touch the data anywhere, convert pcm to dsd or something like this.... for me it sounds best as it is, playing pcm as pcm and dsd as dsd)
i´ve build the "air partners" but i had a plan.
just downloaded hornresponse, but i have no plan:o
IS IT WORTH EVEN TO THINK ABOUT A CHANGE?
The Exemplar horn looks like it may be a better match for time aligning the compression driver to the cone driver.
Straight horns are generally a bid better in the upper mid range, but you certainly won't convince anybody that has heard a spiral horn like the classic Western Electric horns that they did not have a good midrange.
Those horns used one driver, which eliminates the time alignment and crossover filter issues that multiway systems need to address for accurate sound reproduction.
If the horn outputs don't line up in phase at the acoustic crossover points, they simply will lack the coherency that is possible.
The wavelength of 500 cycles is about 69 centimeters, to be within 1/4 wavelength requires the path length difference to be no more than 172 mm.
Have you tried moving the 511s back so they are in time alignment with your present mid horns?
Acoustical time alignment also may require a polarity swap depending on your crossover, and may not exactly correspond to the physical path length difference.
The reason the subs did not integrate well could also be a time alignment issue.
Anyway, unless you are just itching to make some sawdust, I'd suggest working on time alignment before you EVEN THINK ABOUT A CHANGE in cabinets.
One other detail- if the unused subs terminals are not shorted, they may presently be acting as bass traps, further reducing the output of the folded horns.
Straight horns can sound better (you say high frequency but i think you mean midrange?) but why not just raise your chair 6" and listen on axis if that's what your goal is. The Exempler horns are too short to be worth pursuing in my experience with them and they have weak bass. They are a step up from the Altec horn bass reflex combo cabinets but are otherwise not worth the wood and time to build them. What would work well maybe to build some proper subwoofers (biamp) that will "keep up" with your present bass horns and maybe upgrading the mid horns for the compression drivers.
time aligning...this is a major reason to think about it(btw, polarity is swept between midrange and bass). i played around with the 2405 and s2 for a long time, height, distance, the whole thing is VERY sensitive to this, each mm counts.
of course the midrange-bass is not that problematic, but....
the subs...they are no longer in the room and i dont miss them. maybe i try tapped horns later...
there is some itching to try the 515´s in a straight horn.
i did not measure my horns, but i think they go a little lower than an a7. not much.but they sound way better to me,cleaner, not like a paper box. 1,5" plywood on the sidewalls, sand...rounded also on the inside of the horn. heavy.
BUT:: maybe the gpa 515 can do more? in a horn like the exemplar?
the we horns: never heard one of these, i love them anyway, they look just great!!! i thougt about building one of these, the folding is more "gentle" and if i use the space behind my speakers....
time alignment ;-(
The exemplar is bass reflex like the altec a-7, if you want to improve upon your folded horns you will need a straight horn as long or longer path length than your present horn with a larger mouth, that is if you expect them to go as low
the bass.... this is the question!
if something like the exemplars are as good as mine(50hz???), fast, at least as good, and i get better midrange it will be an upgrade.
my speakers are also bass-reflex, but i think it works by accident:eek:
if i can get a compareable bass and better midrange...thats it!
its just a feeling...a straight horn should be better at 500hz.
thats why i ask:)
They are fake, they only horn load to about 150 cycles. I've heard them in different rooms and find they are better than altec short horn/reflex combos like A7 but are no where near as interesting as a fully horn loaded bass system. The reflex part is the compromise in the tucker exemplar, as is the tractrix flare, as is the short path length. A straight bass horn as long or longer path than your present horn with a larger mouth (not tractrix for bass) is where I would look for improvements in the whole entire pass band
I know you may think it blasphemy but just removing the cells in the 311 horn will help the on axis sound more than you can imagine. I have done this long ago and it will clean up the on axis sound and not really do much for the off axis response. The 311 horn is thick enough that you will not cause any ringing in the flare.
@pooh: dont forget the size of my room!
i thougt about building a straight 80hz horn with subs and crossover on the software side. but this does not work, any dsp on foobar destroys the sound.
I'm starting a project for a straight horn (GPA 515G) to cover down to 60hz with matching polars where it crosses to the an Altec 1003 horn.
Right now I'm using a 80hz conical horn (front loaded) that works well, but I think it can be improved at least in theory.
Shame you don't live close by so we could compare notes. :)
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