horn loading changing impedance

[bfish]

Originally posted by bowtie427ss:
Wouldn't the OP's particular situation be an ideal app for the 15067 matching transformer?

<font size="2" face="Verdana, Helvetica, sans-serif">To be fair, given a qualifying application, yes.

[bowtie427ss]

You still haven't sold those things yet?

<font size="2" face="Verdana, Helvetica, sans-serif">loaned a couple for an app similar to the OP's which made me decide to keep the others on hand just in case.

The gent who borrowed them has mentioned that there wasn't a degradation of sound quality as he was expecting, he's using them FR i believe.

[Old Guy]

The trannies would work fine for the OP's app.

Horn loading raises a drivers impedance, not lowers it.

In the case of small horns usually ignored.

FWIW EDCOR mkes a similar tranny, but not as nice as the Altec.

The 100 watt Peavey 70 volt can also function as an autoformer.

[bfish]

I can't remember who at the moment, but isn't there a member here with the same, only inverse, problem...?

Never mind, he's in the same boat. Sorry.

<font color="#FFFFFF" size="1">[ November 10, 2007 10:39 PM: Message edited by: bfish ]</font>

[bfish]

Since the impedance conversion in this case needs to occur between the 8 ohm XO outputs and the 16 ohm drivers, 4 xfmrs would be needed to convert a pair of 2-ways. Although the insertion loss is acceptable (0.3dB each) and the xfmr BW is adequate for stock 2-way VOTTs (30-15kHz), the added L and R will to some degree affect the overall performance. Given the availability of used XOs or the relative small expense of building new, I know which approach I'd take...

...neither. I'd biamp!

[Old Guy]

I wouldn't advocate trannies on the HF. Resistive matching would work fine, since the higher loss is acceptable.

New xovers are prolly the best, if within the capabilities of the builder.

[bfish]

You lost me there. To make the 16 ohm driver appear like an 8 to the XO, you'd need to parallel a 16 ohm resistor with the driver. Then half the HF XO output would be burnt up in the resistor, would it not?

[LICORNE]

You must change the capacitor value and inductor value .

There is no other way.

..........

<font color="#FFFFFF" size="1">[ November 13, 2007 05:56 AM: Message edited by: CONVERGENCE ]</font>

[bfish]

Originally posted by CONVERGENCE:
...There is no other way...............

<font size="2" face="Verdana, Helvetica, sans-serif">Not an average-user-friendly one anyway. Just wanted to show why the XO has to suit the app. That's why there's so many of 'em...

It would be nice to hear from valhallax, to see if my assumption of his need is correct, or if we're just burnin' bandwidth. If not, always glad to provide the entertainment!

<font color="#FFFFFF" size="1">[ November 12, 2007 07:14 PM: Message edited by: bfish ]</font>

[valhallax]

ok , im back. heres the deal.. i had an extra set of 828 cabs. see thread 'a-5's rocked the house' they were set up with alinco 418b's and a set of 805's. these are 8 ohm speaker and drivers. now we all now a mi speaker is not the same as say..a 515, or a 416 sonically. these speakers i let my ex father in law use. he's an old hippie and loves music. he was in detroit for the riots and saw many of the great bands of the era. since he has the a-5's now he even loves classical. his interests are predominantly in english blues and early electric jazz. i won a set of 416 8c's however upon arrival the one had severe coil rub. i have a set of 416-16c's that just thunder in my biamped setup. i was hoping somehow to get them to work in his sytem. while i love the guy, my funds have been exhausted where he is concerned..i think. was just trying to get around leaving mi speakers in those cabs. i guess its another set of speakers off to bill for rebuild. 16 ohm crossovers arent as easy to come by, the time i have to reseaerch cap values is very limited due to the fact i raise these kids by myself, have for ten yrs now. for what its worth, there will be no way of biamping these a5's, doubt he could run it. he uses his tv as a preamp and a very cheap pioneer reciever. to me its about spreading the word. most say.."altec?" and im doing my very level best to educate everyone i think may listen, the attributes of altec gear, and if his a-5's sounded better, i.e. more bass, you know how folks just love bass these days. i swear this guy allways has folks over drinkin' and.. tons of folks jammin to a spare set of speakers. enuff for now, i think im going on and on here