Electro-Voice Marquis

mhardy6647

The tweeters on the drivers are oriented with their long axes vertical in the cabinets, aren't they, @Jstas ?
I am pretty sure you know this, but they're diffraction horns, so that's the way to orient them for the best horizontal dispersion.
Paul Klipsch (bless his heart) usually installed them the wrong way in his loudspeakers -- it's also not uncommon to see the coaxes installed 90 degress from the proper orientation in enclosures. Since the enclosures and drivers were often bought separately in the old days, it's a bit of a crapshoot.

The T35 family, while very forward, are also very rolled off at the top -- i.e., your description sounds like typical T35 behavior to me. I think EV spec'd them for 17 kHz, but internet wisdom seems to think they're about done at 13 kHz.

mhardy6647

EV always implied (or, at least, I always inferred) that the salient difference between the T350, T35, and T35B was sensitivity, but I think (??) there's more to it than that. The T350 was certainly the pick of the litter, and prices reflect that To my ears the T35B is better behaved than the unsuffixed T35 -- but that may be application-specific.
I imagine that the driver in the 12TRXB is essentially a T35B -- but I don't know that for sure.
(EDIT: Zilch sez that the 12TRXB uses the T35B as its tweeter.)

All this is by way of "sharing" the FR curve that the late, great "Zilch" published for a T35B.
I don't know if this is representative of "all" T35B response curves, but knowin' the ol' Zilchster, it's safe to assume this is an accurate respresentation of the one he tested.


https://www.audioheritage.org/vbulletin/showthread.php?10252-ElectroVoice-T35-anyone-familiar-with-them&p=199399&viewfull=1#post199399

Here's an EV curve for a T35. The X36 mentioned was their potted 3600 Hz XO for same.



Note the sensitivity

mhardy6647

Jstas

Oh, I'm not sure how they are oriented, that would require taking them out as the grilles are secured on with a wooden trim frame. I haven't done that yet. Didn't want to risk breaking them. Not sure how fragile they are or how the cabinet is put together. Additionally the drivers are mounted with nuts and bolts and if I undo them, I might not be able to get to the other side to keep the bolt from spinning. So I have to figure out how to get the frames off.

Inside, on the back of the baffle board, there's screws that go around the perimeter of the board and judging from pictures of other EV speakers I've seen from the same period, that's probably how the frames are held on. But now that I know they are in working order, I want to be real careful pulling them apart.

They will image well but the sweet spot is pretty focused. When I was standing in front of them on the workbench I was less than 3 feet away and as close as 6 inches, any speaker would have trouble with off-axis response at those distances. If I backed away and sat down to closer to the tweeter level, high end response was impressive for the age of the speaker. It's not as detailed at the high end extreme as more modern drivers but for a 1955-1965 era speaker it's impressive.

I was more surprised at the roll-off of the off-axis response and it's likely because the drivers are bottom mount on the baffle and it creates a bit of a tunnel that the tweeters are shouting in. With the drivers oriented at the bottom of the cabinets, they are going to be shrouded a bit at a steep off-axis angle. Like if you were changing a rekkid on your turn table and your ears were basically inline with the baffle. The baffle itself will shroud the tweeter.

I don't think they are rolling off at 13k, though. There's a drop in sensitivity above that but 17k is more likely the roll off point because they don't get the fatiguing sibilant sizzle at the top end that more modern horn drivers tend to get. They also don't have the cupped hand shouting aspect that something like the Heresy pair I have tend to lean towards. Those absolutely need tube amp power to help tame them. The EVs also don't get shouty or screechy at the top end and the programming is there, it's just a bit muted if that makes sense? You can turn up the volume though and there's information there above 13 kHz, stuff other vintage speakers I have miss. It was readily apparent with the NAD 902 amp which had no problem driving them but did make them seem a bit sterile.

Additionally, I have a set of KLH 20's that roll off around 15kHz in the garage as well and the EVs were performing better, especially on that track I posted with the YouTube video that has all the piano and violin work.

The switches on the back still seem to be working too and I should probably see if they are both set to the same setting. I neglected to check and that may be a source of odd response drop off.

michaeljhsda2

I wonder if shining a bright light up close will reveal the orientation...

Jstas

Tried that but like Doc's images say, the horn is matte black and with the black fabric behind the fancy fabric, you can't see much but shadows.