elcapitan83

excellent work. did you use a spraybooth to get that finish? my main problem is always dust nibs in my finish.

thanks for all the replys. here is the original post by djk that got me thinking: "The taper rate of a LaScala is 100hz,The mouth area is good for 125hz.Below this it is a big woofer in a small sealed box.If we plug the T/S parameters for the K33E into a box program we will see that the Qtc=.85, the Fc=82.5hz, and the F3=70.9hz . If we close in the back of the high frequency cabinet and open the woofer rear chamber up into this volume and fill with fiberglass we now have Qtc=.577, Fc=58.2hz, F3=73.6hz .Bessel=Qtc.577=D2 gives the best transient response and the least group delay of all the sealed boxes.At 30hz the Qtc=.577 has 4.5dB more output than the Qtc=.85 .Compared with sealed enclosures,the transient performance of the best vented enclosure is worse than the best sealed box enclosure.Since we have made great gains in performance some may elect to stop here.But please read on.The next step is to port it.The K33E is not the optimum woofer for this but it works pretty good.With the box size optimized for a D2 we can port the stock woofer to an SC4.The transient response of an SC4 while not as good as an SBB4(more on this later)is better than the more common QB3.Unequalized the F3=49hz and has 3dB more output at 30hz than the D2.The response curves are parallel with the D2 the only difference being the Fc being a half octave lower with the SC4 and the output being 3dB higher from 30~70hz.The output of the SC4 does not drop lower than the D2 until you go below 17hz.Again this may be a stopping point for some.But by adding a simple two pole high pass filter ahead of the power amp we can now have a C6 with a -3dB point of 31hz.Since this is the Fb of the system there is no increase in cone excursion or distortion.The filter consists of a cap an inductor and a pot.The pot allows adjustment at Fb of +/- 3dB.This is similar to being able to change the Qtc of a sealed box from .5~1.0 .If you think about it we have the choice between a D2,SC4,and a C6 in the same box by plugging the port and/or bypassing the eq.If you have a SET amp or simply want to get the most out of the LaScala you will want to upgrade the woofer to something with a lower Qts.The Klipsch K43E does the trick,as do the EV DL15W and the JBL 2205.The EV and JBL drivers require some minor network changes.The lower Qts drivers allow for an SBB4 alignment which has the best transient response of the vented alignments.With no eq they have 3dB more output at 30hz than the stock woofer.With eq we have a maximally flat B6 and the F3 of the system is 27~28hz.If using a solid state amp with the low Qts woofers a small resistor must be added in series with the driver to have the same Rg as the SET does.This mod can be backed out of a stock LaScala with no externally visible changes if you don't like it.No one has ever gone back to stock after hearing this mod.Paul Klipsch was violently opposed to the venting of horn speakers bassed on his experience with venting the K-horn.In retrospect it is easy to see why.The 12" Jensen field coil woofer he was using had an Fs of 60hz and a quick calculation of the vent area vs the Vb based on the photographs of this experiment looks like an Fb of ~80hz.I am sure this sounded horrible.Paul Wilbur Klipsch is a giant in audio.If I appear to see farther than PWK it is only because I am standing on his shoulders." sorry for the long post, what i had in mind was construct a speaker "stand" the same volume as the top chamber, and fasten it to the base of the la scala. port to taste, and i have a reversible mod if i dont like the result. which threads to research for the effective porting?

hey marvel, check the sams photo facts page for a schem, they might have one on file. if not, i got a scan of a sams photofact schem for my Knight from a guy in British Columbia. I have his email, if you are interested. It cost me $5, and has been invaluable.

ok, admit 20hz is a bit low! let us go for 32hz, instead. i dont know, the 'scalas are better from corner placement, but i was thinking of building a set of "bases" that the speakers would rest on. if i opened up the bottom chamber, i could pick up more interior volume, and i could lower the frequency response? i had heard of some guys opening into the sqwak/tweet chamber and inclosing the back to pick up volume, and instead of doing that, thought it easier to construct my own "base" and tune until i get the response i want. i use these speaks for stereo hi-fi only, and i really detest subwoofers. i thought that it would be more simple to do it this way...but...apparantly, its not so easy as all that.

so, according to your replies, flush mounting the k-77 is in order, huh?

! you have a knight! which model? i did a recap on a knight kn-740, stereo integrated amp with 4 6l6gcs, push-pull cathode biased, with 5 12ax7s in the preamp. that little amp sings! granted, i may have increased the capacitance too much (doubled it), i get arcing randomly in the 5u4gb. how do i get rid of arcing? my power tranny also runs hot, line voltage here is 125v! i am looking to get a variac, i suppose

Does anybody know the diffraction angles for the k-77 tweeter?

thanks a lot, guys. in particular, i was looking for the formulas between cabinet/horn dimensions and low-end response. i realize that the low end of the lascala is hampered by it's physical size. increasing the volume will not just increase the low end response, however. i was wondering how to calculate cabinet volume and motorboard opening dimensions for a given low frequency response. lets just say that i wished to use the stock k-33e, and wanted a bass response down to 20Hz. What would the interior volume/ motorboard throat dimensions be? thanks, scott

Hello all, I was wondering who could reccommend a few good books dealing with the principles of horn loudspeaker construction. As much as I enjoy the learning I recieve here, I want to examine how my LaScalas operate from a "textbook" point of view. Thanks, scott

Hokay, regarding Output transformers. This is for tube amps only. i would think that using a single output tranny in a stereo amp would be advantageous, as you lower the parts count (cost) and at the same time, do not need to worry about putting together a matched "set" for the left and right channels. why then do many manufacturers have dual OT? is it due to the nature of the amps? (separate L+R channels) the problem with separate channels is now its a real bugger to get them matched...opinions? advice?

dou dou, mon nom est LaLiberte, mais je suis american.

actually, they are on the second story, on some pretty thick carpet. i am considering making some angled bases a couple of inches high, maybe with a couple of spikes on the bottom. should help with better coupling, and throw the sound better into the room. i used to have an old set of epis that i added about 40lbs of sand into. weighed a ton, but talk about coupling! so yeah, possibly a base filled with sand with some spikes for the carpet. where do you guys source your spikes? i have access to a lathe, so i could possibly turn my own. which material would i use? steel? aluminum? brass? opinions on the hiss? is it my old x-overs, or more a function of the drivers themselves?

where to find EV SM-120A? i am having difficulty tracking one down thanks, scott

as a tube head here, i cant honestly say that i deliberate over wires. i guess what i am saying is that i would like to have a cable as transparent as possible, and let the other variables dictate my sound. also, as i have point to point tube amps, i can change LITERALLY every component of my tone. trust me, you start to look for ways to simplify!

this makes me glad i joined! thank you for the quick and knowledgable replies. yes, i have been quite pleased with that little knight, believe it or not. of course it could use some new electrolytics and such (the tranco transformers are dated 1959!) but a sweet little setup that really cooks. yes the hiss is both left and right channels. i have it in both the onkyo and the knight. i had hiss when i tried them(briefly) thru a samson servo 550 (solid state) as well. so this makes me think...old caps in the crossover? i have no qualms upgrading the x-overs. i actually had heard some guys in these forums offer kits. i am diy all the way! i have built several little tube amps and electric guitars. as to the bass, i was almost afraid of hearing that. (new woofers won't necessarily increase bass response. for what it's worth, i have one in the absolute corner of the room, about 3 in from the walls. the span is about 8 ft. i have sort of an odd layout in my room, its roughly 14x14. the speakers are in my bedroom, as i still live with my folks. i would like to build a pair of stands to increase the definition a bit, maybe a "tighter" bass is what i am going for. again, i dont listen to much rap or anything. actually, a lot of who, zeppelin, and the like. i will have to look into front mounting the horns. anybody done this on their la scalas?