Electro-Voice SM120 mid horns

[Shock-Late]

Hey guys

just bought a splendid pair of EV sm120 sectoral horns for only 60 euros...don't have them yet, they're on their way...

I saw a guy here who has such horns on his scalas... would like to see that installation again but can't find the topic anymore...

Would like to know if there is any measurable benefit of having the horn attached to a wooden baffle ( I know that with the K400 horns it helps lowering the cut off frequency, but don't know if this is necessary with SM120 horn)

Also i would like to know if placing the tweeter co-axially in the horn, as EV does for PA application, would be a good idea for hi-fi... doesn't it cause some diffraction to the midrange frequencies???

thanks dudes :-)

Frans

[Shock-Late]

(here's a picture of the horns i bought)

[TBrennan]

Shock----I used SM-120As with my LaScalas, I simply sat them atop the cabinets, nothing fancy. Here's a picture a German fella sent me of his 3-way EV horns, they look much like LaScalas but aren't.

[Marvel]

Tom,

I think I've seen that pic before. Isn't that a KHorn upside down up in the corner (painted white)?

Marvel

[TBrennan]

Marvel---Yeah, I used to have that picture on my Chicago Horn Club website, which is now kinda slipshod (moribund?), I've lost interest in it, I'm actually losing much interest in this hobby.

Yes, that's a homemade KHorn bassbin up by the ceiling as a sub. That is one of the right ways to subwoofer bass limited basshorns such as LaScalas, Altec 825s or Peavey FH-1s.

[J M O N]

Looks pretty nice. Let us know how they sound when you get it all set up.

[WMcD]

I have a pair of SM-120 horns which I offer for sale at $200 for the pair.

I purchased them, used, about 10 years ago. They're in good condition. There are a few nicks and scratches. Perhaps dusty.

My original intent was to use them with a self constructed K-Horn. I eventually worked up a variation on a K-400 out of plywood, instead.

They're in my sister's garage in Dallas. If you buy them, I'll ask her to take them to the local UPS store and pack them. You pay for packing and shipping costs. Of course you might pick them up yourself too.

They are a bit too tall to fit into a K-Horn or LS. You might be able to make it work if you trim off the mounting flanges though. The do take the one inch drivers.

I'm a trusting guy and you can write me a personal check when delivered.

Send me some PM. First offer of $200 (plus shipping and packing) takes them.

Gil

[BerndH]

Hello Frans,

I can't give you any answer to your questions, although i use the same horns on my klipschorns. They simply lay on top of the bass bin. They sound for me much better than the K-400 horn.

I can give you two other advices:

1) Read my topic "K55-M power rating and impedance" from 12/20/2002 in the technical question forum. Here is the link: http://forums.klipsch.com/idealbb/view.asp?topicID=28791&sessionID={563F7B5C-677F-408F-962F-AC1FA50796CF}

Adding the resistor and cap in the network does a better job than without. That's what i personally think.

2) I found the best distance for the mid horn mouth from the bass bin front is about 5 cm back. That gave me best time alignment between bass and mid driver. At other distances the sound of i.e. the kick drum comes twice: I heard one kick from the bass driver and a second kick from the mid driver. The sound in the mid-bass region changed in other ways too, but hearing the kick drum only once was the most important for me.

Bernd

[Shock-Late]

can't wait to get mine!!! they're still on their way....

looks like you're very happy with them. Do you have any picts of your modified k-horns? where do you mount the tweeters? i'd like to mount mines vertically in the mouth of the SM120 horns, using some thin home-made brackets or something. I think it could give fantastic results as long as stereo imaging is concerned....

[CaptnBob]

That's a good horn-Electro Voice designed them in their effort to unseat the Altec A-7 as the studio monitor of choice in the 1970s. I've got a battered pair in my Sentry IVs (Think giant LaScala with twin 12" woofers instead of a single 15".) The horns are freestanding on top, with a bracket to hold the tweeter hanging down into the mouth of the woofer horn.

The instructions from EV strongly recommend putting vertical braces across the front of the horn - there should be little holes there already - to add strength and minimize resonances. On the stock Sentry IV, these braces are part of the tweeter bracket.

A similar horn, with out the braces, was used in the Sentry III (Think Cornwall on steroids).

My admittedly unscientific impressions are:

K-400 - better "Throw," crisper and more detailed.

EV ST-120 - better dispersion, smoother sound field, less colored and agressive.

A final note. About twenty years ago, when I made my first aquaintance with the Sentries, I put them up side by side against the Cornwalls. On the Berlin Philharmonic recording of Vivaldi's "Four Seasons," I could hear a harpsichord playing along gently behind the strings during the final movement - at least on the Klipschs. The Sentries had a more "violin" like sound - but the harpsichord was gone.

I hope this helps. I would try the brace across the mouth of the horn. The factory seems pretty insistent about it in the instructions.

[Shock-Late]

Wow... thanks for the informations... those EV sentry must be cooool...

could you post some pictures of them please? I tried to find some on the web but no success...

I didn't know about those bracket, well i thought the holes where made to mount an EV st350 tweeter... in the mid horn's mouth.

[BerndH]

Shock-Late,

attached is a pic of the EV Sentry III with the SM-120 horn and ST-350 tweeter. I hope i understood you right with your question for a picture.

I agree with the tonal description given by Captn. Bob. Also i don't believe the K-400 more detailed than the SM-120 - but i don't listen to classic music.

Bernd

[J M O N]

Gil: Do you still have your horns available?

[Shock-Late]

Bernd, I agree with you, this horn sounds way better than the K400, and IMHO it is acually MORE detailed. I was amazed the first time I listened to them on my Scalas. I'll never return to the K400! Those EV horns sound much more natural, open, and give a much wider sweet spot. They look great, too! And they're not cast metal, so they don't ring!

[BerndH]

Frans,

nice to hear that you have the same impression of these horns. Today i can answer your first question, if there is a notable difference when they are mounted on a baffle or not: I say no! See my pic with the new top section how they can look.

I really recommend the crossover modification, which i received from DJK. I gave you the link in my first contribution in this thread.

Bernd

[Shock-Late]

Well... I can't really understand WHY one would need to modify the crossover just because he uses some different horn lenses, assuming the cut off frequency is the same. But if you're telling me it really makes it sound better with those EVSM120A then maybe it's worth a try? (that's the great thing about this hobby: it's never over!)

BTW, those horns look great the way you use them. I can't do the same, tho, as I'm using LS and the SM 120 horn is actually wider than the bass horn! No way to baffle-mount them... but I don't really care, it looks OK like that. Maybe I could buy some beautiful HI-FI dampening feet to put them on, would look more purposeful and probably damp some resonances...

[J M O N]

BerndH:

Since you're using these with Khorns, and obviously you have them in a corner, do you sense any problems with side-wall reflections since this is a 120-degree horn and the corner is 90 degrees?

[J M O N]

Oh, another question -- what are they made out of if they are not metal?

[TBrennan]

They're cast of thick plastic like material, VERY think and well self-damped. EV called the material a "resin".

[BerndH]

@Frans

Since i have these horns for more than a year with the modded crossover, i can't exactly remember why these mod is recommendable. I mean, that the tonal balance, the transition from bass to mid, was effected in a positive way?! Try it, the parts are cheap, so why not.

@JMON

I cannot locate side wall reflections at my listening position. I have a living room 18' x 24' tall, the Klipschorns are in the corners of the short wall, i sit about 10' away from this wall. When i go back, about more than 15' away from the source, the sound becomes worse, somehow blown and washed, probably from room reflections, standings waves and other influences. But i had this phenomen with the K-400 too.

Bernd