Q about Crossovers and my CornScala ( photo included..)

[Georges]

Hello

After reading and reading I decided to embarque in the ala mode project of mixing the bass bin of a Cornwall with the mid-high of the Klipschorn. The unfinished result is on the photo. For the rest of the descussion here the techicalities. Cornwall from 1977. Mid horn the Atlas with the push-button to put the cable in. T35 the round magnet one. Original Crossover type B.

So I emptied the bass bin from everything except the Woofer.

Install the top housing the mid K400 metal horn Plus tweeter.

Crossover then the dilemma. I looked on the various comments/tests/etc on the forum. I opted to start from with the AA crossover. So the woofer got the coil from the original Cornwall crossover, the mid horn was cabled to 4-0 on the Autotransformer, via a 56uF cap. install also the non-p-trap combo (.2mH+4uF) on the Atlas, for the tweeter it goes to 5-0 on the autotransformer after the various 2uF caps and .2mH coil as on the original AA schema. plugged everything to my amp ( monoblocks from Fisher 100 with EL37 etc) AND:

I cannot decide. Definately there is less bass than the Cornwall. Much more mid-high too much I could say.

the total image is not so impressive. especially the lack of low frequency; the whle thing is less punchy also.

So do you have any comments ??? To say also I tried in the beginning to leave the crossover as is but replace the 4uF with a 7uF...No much worse...Thank you

george

[Guest " "]

here is a copy of the cornscalla xover. I think Bob posted it.

sounds like you do not quite have a cornscalla xover.

[jwc]

I have heard several XO's on the Cornscala. I have what you have essentially. Don't use the AA network.

The Cornscala will work well with the type B network w/o any modifications. It will sound good...better than the Cornwall as the mids are coming from the K400 crossed at 600Hz. That alone is the BIGGEST improvement you will get from the Cornscala concept.

The next option is to just change the 4 uf mid cap to a 7uf. This will bring the mid crossing down to "around" 400Hz.

Now that is what I have now. There are other more expensive options that will sound even better...but the above is what to do first.

You can't use that Cornscala II schematic posted with the T35A tweeter.

jc

[jwc]

take a gander at this:

http://forums.klipsch.com/forums/thread/678125.aspx\

jc

[Guest " "]

Here is one for cornscala I. I think this is also cooked up by Bob.

[BEC]

George,

For the driver set you are using, just use the type B crossover like below and only change the 4 uF cap to 6.8 or 7 uF cap.

Bob Crites

[BEC]

SF,

Please delete the schematic you posted above. That one is not right. The woofer cap should be in parallel not in series and its value should be about 68 uF if used.

Bob

[mark1101]

Questions:

If you are using the cornwall cabinet is it correct to empty it and just plug the openings?

Doesn't the area in the box displaced by the tweeter and midrange horn/driver combination have to be accounted for to achieve the correct bass bin dimensions?

[jwc]

SF

That last schematic you posted was mine from Bob's Test Box thread. In that thread you will see that I changed the schematic to have 3 different 33 uf caps running in parallel with the woofer filter.

Mark. Yes to do it that way, you would need to leave in the k600 horn and plug the hole for the driver. Then remove the tweeter and put a metal or wood plate over the cutout.

The volume displacement of the K55 and K77 driver/horn assembly is minimal. However, removing the K600 horn from the cabinet may be a bit much. however, you could argue that wouldn't make much difference either.

I have the exact volume displacement of the above mentioned by submerging them into water. That is how I calculated the EXACT internal cabinet volume of the cornwall to make the Cornscala. As my Cornscala cabinet only has the K33 in it.

It is nice to see those trying out the Cornscala concept as I think it is a no brainer. To my ears it is more appealing than the Cornwall or the La Scala.

jc

[Guest " "]

ok, here is the cornscall version with the 3 33uf caps from that thread.

[Georges]

Hello,

thank you for the informations; definately this 100uF on the woofer helps a lot and I use a crappy electrolytic sprague Atom...I assembled one of the 7uF type crossover. I will listen to the speaker for a few days to get the ideas clear. Still i am puzzled why Klipsch change so much the mid-freq section for the Klipschorn/Lascala. Apart the cutoff is it the efficiency of the horn versus the bass-reflex ??!! There should be a reason..

cheers

george

[formica]

Just marking the thread... [:$]