|
High Efficiency Speaker Asylum Need speakers that can rock with just one watt? You found da place. |
|
|
|
High Efficiency Speaker Asylum Need speakers that can rock with just one watt? You found da place. |
|
In Reply to: RE: Alternative to the EV ST350 horn tweeter on EV Sentry IV-A's posted by Geary Lyons on October 28, 2013 at 23:12:02:
Geary
The Linkwitz-Riley XO comes from direct radiator land where it's useful to focus the main lobe radiated in a 2 way box speaker. In a rig like the Sentry lV, the mid and tweeter horns will dominate the dispersion in their pass bands, and the natural steep bass roll-offs of the horns will dominate at the lower ends, so a 2nd order Butterworth should be fine.
As I recall you mentioned using a 45 or 2A3 SET amp which would indicate a music listening application for the Sentry lV's, and it's rather unlikely you would blow an ST350 with a sub 5 Watt amp. You would have to push the amp into hard clipping with a test signal long term to do it. I use my ST350A's as rear firing tweeters in a 3 way di-pole horn rig with 6 drivers per side, and I cross them at 2500 Hz with a first order series crossover. The forward firing tweeters are T350's, and I've been running them with 2500 Hz 1st order XO's for well over a decade and I have never blown one. Ditto for the T35's which the ST350's recently replaced. If you are concerned about this, you can use the STR tweeter protection modules, but I had these back in the 80's and never heard one switch out even with a 100 WPC SS amp playing loud rock'n roll, so they went in the parts box. BTW the EQ circuit will in itself offer some protection to the tweeter as it's shunting energy through the resistor. I just don't see tweeter protection here as an issue, but as I don't have control over your rig, I'm not gonna guarantee your voice coils ; )
I don't have a freq. resp. graph for the 1823M, but my 1823 and 1824M's start to roll off quite steeply much above 2500 Hz with my DIY tractrix horns, hence my choice of this XO. Crossing the 1823M and ST350 at 6 K would guarantee a dip in the response between them. Though a 4500 Hz XO may give acceptable results, a dip could be expected there too. Once again, you could straiten this out to a degree with active EQ, which would be there anyway for feedback suppression in a pro sound setting.
I'm not sure exactly what you mean with the "bumped" XO idea. If you parallel three 0.12 mH inductors, they would function as a single 0.04 mH inductor in a circuit. Why EV spec'd it this way is hard to say, perhaps it was cheaper to do it this way than a single 0.04 unit due to parts availability, and they had 0.12's on hand from something else. You can connect inductors in parallel to get a lower value, or in series to get a higher value. Caps have a reverse effect and are connected in parallel for a higher value, and series for a lower value. There are online calculators for this (do a search with "parallel inductor calculator" etc), as well as calculators for XO's and notch filters (which the ST350 EQ circuit is), see link below.
BTW The spec'd 7.5 Ohm resistor in the EQ circuit can be hard to source, so I used two 8 Ohm resistors in series, and paralleled with one 8 Ohm resistor from RS which is close enough. I use a 0.20 mH Jantzen foil inductor, and I settled on a 2.20 uF cap. Larger caps (up to 10 uF) did'nt seem to do much, while smaller caps (down to 0.68 uF) shunted so much energy out of the ST350's that the old T35's could easily drown them out, along with some roughness appearing at the upper end of the ST350's with the 0.68. I think you're just going to have to break down and buy some parts. Don't worry, you'll use them from the parts box sometime down the line. I always do.
Paul
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- RE: Alternative to the EV ST350 horn tweeter on EV Sentry IV-A's - Paul Eizik 10/29/1312:45:29 10/29/13 (4)
- RE: Alternative to the EV ST350 horn tweeter on EV Sentry IV-A's - Geary Lyons 14:18:28 10/29/13 (3)
- RE: Alternative to the EV ST350 horn tweeter on EV Sentry IV-A's - Paul Eizik 20:33:54 10/29/13 (2)
- RE: Alternative to the EV ST350 horn tweeter on EV Sentry IV-A's - Geary Lyons 23:01:17 10/29/13 (1)
- RE: Sounds like a good plan! - Paul Eizik 16:51:39 10/30/13 (0)
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2025, Audio Asylum, all rights reserved ]
