justinsweber

other views. the port mouth mimics that of a Cornwall

Not sure just how big... but the Eminence OMEGA PRO-18C goes up to 800hz and seems to like a bigger cab. Doesnt seem like a realistic option. I havnt seen a Cornscala with an 18" LF driver yet.

Volume too big... after doing some reading about port config vs volume. Im not sure how to use to calcluators... Something I need to learn. I did call Eminence and spoke with their tech support. He believed that with the port config I have and a volume of 7.3cu that this is too much volume for a Kappa pro... that the driver will reach its mechanical limits. His sugestion is to decrease the volume. Eminence's website sugests a max vol 6.5cu... Ive used 6.8cu last time and sounds great. When the Caninets are back from the finisher. I will take down exact demensions, and begin to calc internal voume, acoounting for braces and alike. If still too large... 6.5cu =/- 10% I will add material to get be back to the median. Does anyone know the volume of a K33 than for all the help. Bit worrysome that the cab may be too big... I did most of the wood working at a friends shop... so Im attached to these and dont want them to be lemons. I need lemonaid.

Not sure what to make of the above response... In all seriousness. Anyone have exp with cabs 6.5 cu ft and above? Should I really consider adding pannels to reduce internal vol?

I have used vol of 6.8 cu ft and sounds wonderful. What do you all think ... 7.3 or 7.1 cu ft? Adding the pannels ?

The braces will knock it down quite a bit... least I hope. Internally its 23.75" X 23.75" X 23.75" 23.75 x 23.75 = 564in sq. 564 x 23.75 = 13396 in cu = 7.75cu ft before braces and shelf. Looking at VAS ratign for 15" drivers Kappa 15C I think 6.5 - 7ish should be fine. I have used Bob Crites 15" in a cab of 6.8 and sounded wonderfuly. The bracing is pretty extensive. Im open to how best to cal the braces volume. There are 3 45deg braces that go long the edges... ~3" spread. Then there is the blocking... the front motor board. The cross brace... etc. Its at the finisher... wont get back for 2 weeks. All in all im super excited for this... My Origonal Cornscala's are in the living room and these will be for the guest room. One easy way to reduce vol would be to add a panels to the sides 22"x 22" x .75" 22 x 22 = 484 484" x .75" thick = 363 (the sides) 2 panels of 363 = 726 cu in 13396 cu in - 726 cu in = 12670 cu in. = 7.3cu ft or One easy way to reduce vol would be to add a panels to the sides 22"x 22" x .75" 22 x 22 = 484 484" x .75" thick = 363 3 panels of 363 = 1089cu in 13396 cu in - 1089 cu in = 12307cu in. = 7.1cu ft What is the rational for the hanging curtain? How large? Where would you place?

different ideas then Ive seen for braces... I like.. the 45deg brace will reduce the volume some... which is a good thing.

4" risers with 1/2" tirm on top to keep them in place.

24"X24"x24" inside... but this babby is built for abuse. 3/4" maple inside, 1/2"baltic outside. and fully fully braced. I may build new split cornscala's with K401 horns to use extra parts for just save for a quick minute to aford the Selenuim route. Front ports are fixed. the Motor baord is just for the 15" driver.

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After some serious horse traiding with my wife... Gave up my perferredhealth ins provider for PPO... My Cornscala's are in the living room, freeing up precious space for Split Corn Scalas... Here are some progress shots. There is a 2way cab in progress 2.

Cornscla Cab. 6 - 6.5cu ft. ported Just wanted to hear sugestions on other 15" drivers.

Cant wait to see.

I was wondering as to Alt 15" bass drivers. I currently use Bob Crites in mnost of my projects... Cornscala's and like, but wanted some feedback on others. Eminence 15C seems like a great choice too.. any others? It also seems that most are 8ohms not the 4ohms as the K33... Any easy way aroudn this? Thanks for any sugestions in advance. Justin

As an interesting update. I added acustic foam in the cab. 3 layer 1 1/4" for the back panel, and 1" for all other sides. The bass was exaggerated and just did not sound right. I removed all the foam from the sides and gave it another listen... and again sound like sh*t. All foam out and things really sound wonderful again. All the remaining foam is headed back to parts express. $80 painful lesson.Bob Crites advise to me when I asked was "a good cab doesn’t need foam, etc to sound good." Too simple advise for me.. so I had to learn on my own... Wish I had just listened. That said... No foam for me in the Cornscala's or the Heresys. The CS-1 sounded good with foam... go fig.

insides

The Corner

Ive now finished my CS-1s, adding acoustic foam. The Cornscals seem to have a very low WAF, so I send them away for some help. My Cornscala’s are back from the finisher… bit of an upgrade of sorts… My wife didn’t like the natural Birch Finish of the Speakers… So I laminated another ¾” maple to the outside edge and laminated ½” MDF to the inside back panel. The inside dimensions are 14” deep X 24”wide X 35” tall = 11750 cu in = 6.8cu ft. I’ve worked 92+hrs this week... I might be off a touch. I’ve found my dimensions to have produced fantastic results. I will again be using Eminence Kappa Cs, PH800/PV55 CS125 tweeters. The Cab is now 2.25” thick on all sides, 1.25 for the rear panel and stained in a dark brown walnut. Though there has been some discussions as to where acoustic treatments work, I’ve decided to may healthy use. (I’m basing this decision on the differences it made in my CS-1 speakers. )The sides, top and bottom will get 1” acoustic foam, the back panel is getting 1.25” thick 3 layer foam. I will take the suggestion to try one with and one without.

With the Parts Express Foam 1/2" thick 18"x24" pieces.. $9 a sheet ~4 sheet needed.

The the Cab thickend

I may skip the Stuffing for the heresy. Why is good for a ported design. Im working on adding Foam to my Corn Scala... Would pollyfill help... how much... why? Thanx for the input Justin

Question using polyfill. For the Heresy Cabinet: I have built Bob’s CS-1 Robbed Heresy Cab. Its ~1.9cu Ft. I’ve added ¾” birch ply to the outside to stiffen the sidewalls. The inside of the Cabinet now has Sonic Barrier 1/2" Acoustic Foam w/PSA 18" x 24" I intend to add Pollyfill to the cabinet… I was told for sealed cabs 1lb per Cu ft is the norm… does this make sense? Any suggestions? The Corn-scala is now 2.25” thick. 3/4“ MDF, 3/4” Maple Ply, 3/4” Birch Ply. Using a ton of screws and wood glue, have built the Cab. The Cab is super solid! The Back Panel is 1.5 thick… ¾” ply x 2. The front is 3/4 “ ply. That Said I want to use Foam and Pollyfill to enhance the Cab and stop cabinet talk. I was planning to use 1.25” 3 layer foam… nicer stuff (Sonic Barrier 1-1/4" 3-Layer Damping Material w/PSA 18 x 24") and I want to add Pollyfill. From the reading Ive done… some think Pollyfill is super important for vented/port cabs… How do you get the stuff to stay put? How much to use with a 6.2-6.5 cu ft cabinet? Thanx in advance for any suggestions.

Greg, I dont intend to make a perfect 24" sq. Will be a rectangle without a doubt... the point I was raising was about materials and sound cancelation. Ive seen alot of interest... strange and worthwhile way to make the cab silent... but most are heavy and thick... Im ok with both.

I hear both of you... that said... My La Scala bins sounds head and shoulders better at 1.25" vs 3/4" My Cornscala Cabs @ 3/4MDF,3/4Maple A1 Ply are incredible. The use of 1.5MDF seems way overkill I agree... but the shop wants to try and so Id get the material for free. I think I will ultim. go with .5baltic+.75MDF+.5 Baltic. Material costs are not such an issue. Will have to plan more closly for bracing.

I’m giving serious consideration to the idea of building some Split CornScala Bins. Iv been reading on materials used by some manufactures, including HDF. I can’t find HDF, but have been able to find 1.5 thick, MDF. The Plan is to build a 24” cubed Bin with a port shelf and some bracing out of ½” Baltic, Wrap it in 1.5”MDF and then ½” Baltic. Then no one will want to buy or steal J. Anyone else using heavy thick material? The MDF is not cheap… $110 a sheet, but this Bin would be for my music room. My 1st Corn Scala’s are headed to the living room. The Alt plan would be ¾” maple + ¾”MDF +1/2” Baltic.