La Scala Bass Horn's usable frequency range (?)

[m8o]

Hello,

Wondering if someone can help me. What is the 'clean' upper frequency capability of the La Scala's bass horn? When I put a tone sweep to it w/o the x-over network, it puts out nice level even up over 1K. However I know that doesn't mean the cone won't operate in break-up mode with a complex and powerful music signal. Also, I'm pretty sure the horn may/will become 'beamy' or lose effectiveness above a certain frequency as it does at a certain low frequency.

So taking the horn and driver capabilities into account, what would be the highest frequency I'd want to cross the La Scala horns over to the mids? I ask because I'm toying with using a mid horn that isn't capable of going down to 400hz. Does the bass horn do well to 600, 800 or 1000 Hz?

Thanx very much.

p.s. anyone know the power handling of the K-55 driver with x-over @ 450 or 500, as well as dispersion of the edit:K701 K401 horn?

[DrWho]

I don't have the answer, but I too am curious (and just wanted this thread in the "My Discussions" so I can find it again) [A]

[djk]

I've used the LaScala up to 800hz, you can EQ it to measure good, but it doesn't sound the best up there.

Sounds like you have a K700/K55V combo. Just give it a try and see how you like it. Use it on tap #4 and change the cap to 6.8µF, that will be fine for the K700/K55V.

The Atlas PD5 is rated for 40W with a cap at the Fc of the horn. Considering the autoformer, it will handle at least 160W input to the crossover (as described above).

The only time I ever saw a K55V actually burn out was with an amp capable of 600W at 8 ohms driven full tilt on Edgar Winter's 'Frankenstein'. The network probably delivered 150W of synth square waves sweeping from 2Khz down into the K55V, and they didn't like it.

[colterphoto1]

"The only time I ever saw a K55V actually burn out was with an amp
capable of 600W at 8 ohms driven full tilt on Edgar Winter's
'Frankenstein'. The network probably delivered 150W of synth square
waves sweeping from 2Khz down into the K55V, and they didn't like it."

Yeah, that song has toasted more than a few drivers I'd bet!

[JohnA]

[m8o]

They say a picture's worth a 1000 words... [H] I just did impedance measurements the other day (shocking midrange hump with the network from the autoformer I'm assuming) . Will be doing frequency tests soon.

Thanx everyone for the replies. It was very helpful. I see the impedance peaks a tad around 450 and drops relatively above 500 (while on an upward slope) so my amp will correct for that dip a bit; more on that later. The impedance is affected by horn loading (shows rough peakiness) up to 1.5k but I dont' think I'd want to go there.

I decided the 'Potato Masher' JBL Horn (needs an Acoustic Lens) on eBay now would not be a good match. I've inexplicably always wanted a speaker that uses an Acoustic Lens every since I first saw it decades ago. That lens isn't good down to 500 unless used with a verticle baffle; I don't think the edit:K701 K401 location is enough of a baffle above it and the bass horn is below it. (where's that boo hoo smiley) [:'(] Hell, maybe I'll try it anyway though.

I actually have the 701 horn and newer driver, but I'm sure all that valuable information holds just as true with that. What may come as a surprise though, is I'm planning on removing the passive network from the picture, and tri-amping using a transconductance amp (aka constant current, aka variable voltage, aka variable gain, aka impedance follower [8-|] ) of my own design. Parts should begin arriving in the upcoming weeks and I'll begin breadboarding and testing after. If I like that but decide the 'gainclone' IC (for DIY simplicity & most importantly low $$$) that I'll be using isn't 'audiophile enough', I have some transconductance tube amp designs I may give a try and build.

[DrWho]

You got that song on any of your albums Mike? It'd be cool to throw that one in the playlist the next time we get together. I like square waves []

[IB Slammin]

.............

The only time I ever saw a K55V actually burn out was with an amp capable of 600W at 8 ohms driven full tilt on Edgar Winter's 'Frankenstein'. The network probably delivered 150W of synth square waves sweeping from 2Khz down into the K55V, and they didn't like it.

djk,

My brother.....the K55V didn't like it?..........Well, lets look for a driver that does like it.......Could I suggest...........

tc

[freddyi]

wouldn't it be kinda like a FH1?

[darkside]

I know this involves tweeters mainly, but something can be said and
Brian Cheney isn't completely full of stuff...and yes, I do
occasionally read his stuff on the VMPS website (sorry guys)

"What is needed for CD is for all drivers in a multiway to be the same
width, and that width needs to be smaller than the wavelength of the
frequency you want to hear with good or constant directivity. If you
want to hear 20kHz well off axis, that means a speaker no more than
2/3 wide, down to as low in frequency as possible, where it can mate
with larger diameter woofers which are already working into 2 pi (180
degree) space and are about to transition to omnidirectional or 4 pi
space. In the past speakers have been made with long and narrow
drivers. These tend to be tweeters, however, and virtually all exceed
1 in width, which means they will beam at around 13 kHz or lower."

[DrWho]

That's assuming someone actually wants a 360 degree dispersion pattern. [+o(]

[m8o]

p.s. I editted all my previous posts replacing K701 with K401. I'd been saying "K700/K701" thinking that's what the La Scala used. err, stupid me; it's the K400/K401.

[darkside]

That's assuming someone actually wants a 360 degree dispersion pattern. [+o(]

Oh

[stereohermit]

That is the paradox of the horn. The mouth is x size for a given cutoff, but at least with exponentials, this also describes a point which the horn will start to beam. Some feel this is limited to about 2 octaves in width.Us horn enthusiasts dont mind since there is a myraid of clever engineering techniques to circumvent these issues, among others , making this one rewarding hobby!

[Klewless]

360 Degree pattern reminds me of the OHM "F" ( as best I can recall).  It did 360 but was not a horn.  And, not to be outdone, it could do a good job of reproducing a square wave.  Not many speakers can do that!

[DrWho]

so it had an infinite frequency response? [][]

[pauln]

so it had an infinite frequency response? [][]

For that matter, even if a sound source could reproduce a square wave what would your ear need to do to hear it? This is a bit of a trick question considering that the fastest rate of neuron firing tops out at about 1K/s... ever looked to see the physiological principles behind hearing frequencies above 1KHz? Pretty interesting when the frequencies get up there...

[DrWho]

I would think the way an ear percieves a square wave is rather mute, since something that merely approximates it is going to be heard differently...no?

[darkside]

Sorry to go OT here, but what the hecks is a "square wave"[*-)]

[DrWho]

http://en.wikipedia.org/wiki/Square_wave

Here
is an example of how the square wave approximations becomes better with
the increase of frequency response (more harmonics)

A perfect square wave requires an infinite number of harmonics:

Probably more info than anyone wanted to know, but that's ok []

An interesting conclusion is that digitally created high frequency square waves are crappy because the high-end of the response is capped at half the sampling rate. (22kHz for CDs). So a 10kHz square wave only has room for one harmonic (20kHz).