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why baltic birtch?


edmjm

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Most Klipsch cabinets today are MDF.  In years past, birch veneered multi-ply void-free plywood was used.  Whether or not it actually was sourced from the Baltic, it was, and still is, commonly referred to as "Baltic birch."  Many more plys than standard plywood, plus an absence of voids, makes it an excellent, albeit, expensive material from which to build speaker cabinets.

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Baltic birch has been used in Heritage products sparingly over the years due to its void-free properties, most notably in 1/2" for K-horn woofer back panels and interior parts, as well as Heresy backs.  While 3/4 & 1" may be in current use in some pro products, I Don't believe it has seen use as 3/4" material for Heritage.  Klipsch has 3/4" laid up custom in 4 X 8 sheets for non-veneered applications (think old LaScalas).  Currently veneers are laid up on 3/4" MDF since the early 80's.  Prior it was lumber core.  This is a denser, more dimensionally accurate material when kept dry.  PWK was in on the decision.

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On ‎7‎/‎4‎/‎2017 at 7:54 AM, JRH said:

Baltic birch has been used in Heritage products sparingly over the years due to its void-free properties, most notably in 1/2" for K-horn woofer back panels and interior parts, as well as Heresy backs.  While 3/4 & 1" may be in current use in some pro products, I Don't believe it has seen use as 3/4" material for Heritage.  Klipsch has 3/4" laid up custom in 4 X 8 sheets for non-veneered applications (think old LaScalas).  Currently veneers are laid up on 3/4" MDF since the early 80's.  Prior it was lumber core.  This is a denser, more dimensionally accurate material when kept dry.  PWK was in on the decision.

The plywood used in decorator Cornwalls, and Decorator Heresys was GENERALLY contracted from Georgia-Pacific to meet certain Klipsch specification parameters.  It was 5 interior plys with thinner birch outer cabnet-grade veneer on each side of the panels.  There was an ongoing battle with GP over quality control issues the whole time I worked there (1976-1983).  I honestly believe the REAL issue was that Georgia-Pacific was trying to "up the price" during that entire time-frame due to inflation, which was running rampant .  For instance, the contract clearly stated that there could be no voids in the plys immediately beneath the birch outer veneers.  So everything GP shipped for a number of months would be just fine, then all of a sudden there would be voids underneath the birch veneer, which required us to cull those already-cut cabinet parts and utilize those culled parts for other things (such as crossover network boards, etc.) instead of just scrapping them into the trash trailer.  Of course this "upped" the labor costs at K&A of trying to re-purpose culled side and top panels to avoid just wasting them.  I would always slide my hand over the top, bottom, and side panels of birch cabinets prior to assembly, because I oould "HEAR" the voids in the ply immediately underneath the birch veneer....then cull the ones which had "large-enough voids" (meaning anything over penny-size).   Quite often I would end up with almost an entire pallet of voids from one pallet of parts...which was TOTALLY UNACCEPTABLE.  The foreman would be chewing me out and I would be standing my ground on QC...which was the BUILDER responsibility.  Then after a few days of this routine, one of the "powers that were" would call up GP and "raise hello"...which would NORMALLY result in a cost increase to what was being shipped so that the already contracted product would meet the original specs.  Highway robbery, but it was what it was!

 

As for the furniture-grade poplar lumber core plywood that was used back in the day for the finely-veneered mitered cabinets and such, we had similar issues with the Poplar lumber-core itself in those panels, but seldom with voids just under the outer veneer.  I firmly believe that happened for the same reason, since it was generally ALSO contracted through Georgia-Pacific.  If there were gaps between the poplar lumber strips which made up the STRUCTURAL strength of those panels, then it COULD cause the panels to crack when under pressure, such as when using the chain binders when assembling mitered Cornwall cabinets.  I've seen it happen way more than once when "tapping out" the mitered edges in order to have nice-even-sharp-toe-miter edges on the box, while the box panels were in the chain binders...."tap, tap. tap, CRACK!...DAMMIT!"

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Now for the Baltic Birch: 

 

K&A got a REALLY GOOD DEAL on a very large amount of bundles of Baltic birch sometime in the late 1970's, either just before JRH arrived to work at K&A, or shortly afterwards.  It arrived in various panel sizes and thicknesses, with the vast majority of it in thicknesses approximately 1/2" and 3/4" (Baltic birch actually was manufactured in METRIC thicknesses).  So, the decision-makers got into the fray of deciding how it was to be utilized, without even talking to the worker bees in the cabinet department first.  A number of VIABLE ways to utilize it were incorporated, but there were a FEW total fiascos involved, for instance: Heresy and Cornwall drop-in motorboards.

 

The drop-in motor-boards were used on the mitered fine-veneered Heresy and Cornwall speakers at that time, and about the same time the old "Decorator" Heresys and Cornwalls received a new cabinet build technique which also used drop-in front motor-boards.  The drop-in motor-boards were dropped-in and stapled to the glued-up glue-blocks in the front of the speaker boxes.  But, they had to have the holes for the horn lenses and woofer routed on an overhead industrial pin router first, then had to be pre-drilled for the pilot holes used in the mounting of the components once the cabinets made it to final assembly.

 

Instead of cutting a FEW of the motor-boards, to see how the Baltic birch would work out being used for them, the decision-makers had a number of full pallets of them cut.  And, instead of building a few test boxes, the Baltic birch motor-boards were to be immediately incorporated into production.

 

So, no chit, there I was...building at my workbench when I noticed that pallets full Baltic birch Cornwall and Heresy motorboards were being moved over near the pin router...and guess WHO would have to rout out the holes in them? ME!!  So, I finish up building enough birch Heresys to keep the sanding room busy for a day or two, then over to the router I went.  The first thing I noticed was how much harder it was to control the router template while routing out the holes...due to the density of the plywood, and ESPECIALLY due to the multiple layers of urea formaldehyde glue holding all the plys together.  Between the density of the wood plys and all of that HARD glue, the router bits got dulled much quicker than normal...about three times as many NEW router bits had to be used in order to make it through one pallet of parts.  This is because the router bits got too hot, and the braised-in edges literally exploded out of the bits in small pieces (many of which buried themselves into my body or safety glasses!!)  NOT FUN AT ALL! 

 

So, all of them being routed out, with some of them ALREADY being scrapped due to exploding bits creating ragged rough hole edges...off to the drill mechanism to pre-drill the pilot holes...which was also a fiasco!  The drill mechanism was a pneumatically operated unit....with numerous pneumatic drill guns mounted to it, and a pneumatic press installed to lower the drills at the proper speed to do the job in NON-Baltic birch.  You can see where this is heading...broken bits, etc.

 

Now, take the ready-to-install Baltic birch motor-boards over to my work area, and just what I expected to happen, happened!   The staples used to install the motorboards would NOT penetrate through them, and folded up in a wad...so...I tried my best to make things work with what I had available, but it simply WAS NOT GONNA HAPPEN...so I was told to use finishing nails instead from my nail gun...many of them folded, too, and the few which actually went through the Baltic birch still had to be driven in all the way in by a hammer, and a nail-set!  Not only that, but the plywood glue blocks were cracking to pieces and had to be replaced due to the larger diameter of the finishing nails causing them to split.

 

The few cabinets using the new motor-board material which actually made it over to final assembly  had to be sent back for repair due to the screw-heads twisting off when they tried to install the components using the pilot holes.  The decision on THAT part of things was to use larger diameter drill bits for making the pilot holes, but the rest of the plan was pretty much deemed a failure, so the pilot bit decision was rendered obsolete before it even went into effect.

 

So much for that Baltic birch Heresy and Cornwall motorboard idea!  And the stuff that was routed-out was relegated to the trash trailer because it could not be re-purposed once the holes had been cut into it.

 

But, the Baltic birch worked well for many other applications..,..especially so for the (approximately) 1/2" thick stuff!  Heresy back panels and K-horn bass bin sides and numerous other applications in the K-horn bass bin such as "ramp" and "wing" assemblies panels/parts, etc.  I'm not sure if more of the 3/4" Baltic birch was ever bought because it really had few if any viable applications for the building of the cabinets as they were being built while I was there...but the use of the 1/2" Baltic birch was continued through the time I left K&A in 1983....and thereafter.

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So is it an overkill to build cabinets out of Baltic Birch these days?  Is the $50 per sheet of 4 x 8 Oak or Birch ply from the bog box lumber stores going to suffice for most jobs?  I've seem some on here that appeared to have used it with decent results.

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32 minutes ago, avguytx said:

So is it an overkill to build cabinets out of Baltic Birch these days? 

 

 Is the $50 per sheet of 4 x 8 Oak or Birch ply from the bog box lumber stores going to suffice for most jobs?  I've seem some on here that appeared to have used it with decent results.

 

Baltic Birch not overkill. The big box hardwood plywood veneer core is sub-par and full of voids, exactly what you don't want in a speaker cabinet.

 

Even the marine grade ply witch is supposed to be void free has voids.

 

 

 

 

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is that why they switched to mdf? no voids, more consistent quality control & less expensive?

even any of us spending extra for a couple sheets of baltic birtch ply can't be assured there won't be unacceptable voids if the factory was having those exact problems.

 

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1 hour ago, avguytx said:

So is it an overkill to build cabinets out of Baltic Birch these days?  Is the $50 per sheet of 4 x 8 Oak or Birch ply from the big box lumber stores going to suffice for most jobs?  I've seem some on here that appeared to have used it with decent results.

If 3/4" (nominally) Baltic birch is used on LaScala cabinet builds, the stiffness and density of the side panels will be about the same as the 1" thick MDF currently being used on the current LaScala cabinets.  That will negate the necessity of stiffening the bass bin sides in order to "straighten-out" the response curve in certain frequencies which the old standard 3/4" birch veneered plywood never could address, unless reinforcing "wings" were added between the bass bin side panels and the doghouse in order to stiffen-up the FRONT of the bass bin sides (the joinery at the rear of the bas bin sides accomplished that for the most part, but the mouth end of the bass horn sides still flexed too much and needed stiffening to solve the response-curve/distortion issue).

 

In the current LaScala Cabinets, the use of 1" MDF for the side panels solves that issue, but adds the need for 1" MDF for the remainder of the cabinet (top and bottom panels to bass bin) to provide for more positive aesthetics.

 

There are other ways to stiffen the sides of the bass bin, but they are normally much more costly.

 

So, BLUF: If you are planning to build LaScalas, and you plan to veneer them OR paint them, then use Baltic birch for the side panels and top and bottom panels of the bass bin and you will be good to go...you can use the other 3/4" stuff for the doghouse, etc, and still be good to go.

 

Your choice.

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I'm actually planning to build cornwalls from the ground up. I've decided not to modify or molest the original cornwall 1's.

do you think hardwood maple 3/4" plywood could be a good substitute for baltic birtch? I can get cabinet grade here in Canada real easy.  or mdf with veneer?

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I'm just NOT a fan of MDF...it just damages too easily...and repairing that damage is more trouble than it is worth, even if the repairs are not unsightly...IMHO.

 

As for "hardwood maple" plywood, the designation of the veneer type has nothing do with the inner plys of the plywood, generally speaking.  It is the inner ply material, the thickness of each ply, and number of plys involved which determines stiffness of the plywood.  Stiffness is want you want.  If the wood flexes, it is not stiff.  If it is stiff, then it is also more likely to be dense, and density and uniformity of density is what contributes to its sonic qualities.  MDF is used more for its sonic qualities than for consideration of possible repairs later on.  The fact that it is also cheaper also plays a key role in its widespread use.

 

Most manufactured wood products are looked upon as what they are when first unboxed/assembled by the purchaser.  Issues with repairs later on are not even part of the equation of the decision matrix on what materials are to be utilized in the manufacture of the items.  Face it, we are not in a world of DURABLE products anymore.  Functionality at reasonable production costs is what drives things, not durability.

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40 minutes ago, avguytx said:

Were the black back panels on the Belle's (where ramp area is) attached by glue/clamps only or were they glue/clamp/nailed in place then veneered to cover up?  Were the Belle's primarily built that way in their entirety? 

 

@HDBRbuilder

Not sure what you mean by "ramp area"....but all the finely-veneered panels came in pre-veneered to the plant in matching sets for the Belle Klipsch speaker cut list.  As for the construction of the Belle Klipsch speaker, it was THE MOST LABOR-INTENSIVE BUILD of ALL the now-so-called "Heritage" line.  That is why it was always so expensive, plain and simple.

 

A variety of fasteners are used in the Belle Klipsch speaker.  Every joint is reinforced in some way or another with fasteners of some kind...be it screws or staples of some kind.  Clamps were used to some extent, but not that much because the staples were to hold the glue blocks/joints in place while the glue set-up.  The only parts which are removable are the upper section elements where the midrange and tweeter are, which was how it was shipped...as separate units in separate containers, just like on the Klipschorn (except for the "D" style Klipschorn).  So, in that "top-hat" area, the glue blocks are glued to one surface while they are screwed to the adjacent surface, for disassembly/reassembly purposes only.

 

The Belle Klipsch speaker was a "late" addition to the Heritage line, since PWK finished developing it at the tail end of the 1960's and I believe that it went into regular production sometime around 1970 or so.

 

Hope this answers your question(s).

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That helped a lot and makes sense.  The panel I was referring to was the back panel where the serial number tag is attached and on the other side of that is the ramp.  Since not many fasteners (screws, staples, etc) aren't seen on assembly, hat made me wonder if it was glue blocks that were screwed to panels to hold them together....like in the bottom bass bin (the top, bottom, and sides being attached) as I can imagine that the doghouse was screwed, stapled or nailed to the outside "box".  Just trying to get an idea formulated before I take off building.  Thank you, sir!

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On 7/5/2017 at 11:01 AM, edmjm said:

is that why they switched to mdf? no voids, more consistent quality control & less expensive?

even any of us spending extra for a couple sheets of baltic birtch ply can't be assured there won't be unacceptable voids if the factory was having those exact problems.

 

Russian baltic birch is good stuff. Available in various grades--its widely used throughout North America for better quality cabinets and casework; especially in drawer boxes where there is zero tolerance for voids. Russian BB is a creature unto itself. I have never seen a void in sheets that were spec'd void-free. For structural integrity, a careful shopper might find a "close" equivalent--but for what it claims to be... I've never seen better, at any price. (To re-iterate previous posts: "multi-ply" and "super-ply" products may look like BB; be cautious).

 

I do not doubt that K.A. was experiencing quality control issues with their custom material from a North American supplier--but for anyone looking to invest the very considerable time and effort required for a quality speaker build--I would not skimp on the sheet material; and certainly would include Russian Baltic Birch among the better materials available. In addition to the common 5x5' sheets, in 3, 6, 9, 12, 15, and 18mm;--I have also seen it as thick as 24mm (~1 inch) thick and as large as 4x8'.

 

On 7/5/2017 at 11:17 AM, edmjm said:

I'm actually planning to build cornwalls from the ground up. I've decided not to modify or molest the original cornwall 1's.

do you think hardwood maple 3/4" plywood could be a good substitute for baltic birtch? I can get cabinet grade here in Canada real easy.  or mdf with veneer?

 

^ A cabinet grade plywood could be a substitute; but it is not a replacement, and it will not perform like BB. "Multi-ply" and "SuperPly" are tradenames for products similar to BB, and would be an improvement over a standard, mixed-fir, cabinet-grade ply.

 

If you've got a particular species, or grain pattern in mind--you might try to find a supplier to special order one of the available 'multi-ply' products that is already faced with the veneer. Otherwise, a BB build that you face with veneer yourself would allow you to hand-select the veneer; and might yield best possible results. This could be a source of satisfaction, you would enjoy for the life of the speaker.

 

[As an aside: remember that different materials will likely mean different methods of joinery; miters, 'lock joints', glues and mechanical fasteners are all optimized for specific materials and may not "play well with others" (eg. stapling plywood may work, where the identical joint in MDF fails. So, if you follow plans that spec both materials and fasteners, changing materials could also mean changing fasteners/joints)]

 

I thought others reading this thread might be interested in the Dope excerpt, below. MDF is not mentioned, by name, but the principles discussed are as true today as they were then. Screws holding in edge grain, "high-density", breaking strength, stiffness... these all apply to MDF; in some ways even more so.

 

 

5962b7fd74d88_Screenshot2017-07-09at5_08_53PM.png.c1b06f32000b8c643deefb9ae0e3ad3c.png

 

 

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On 7/5/2017 at 10:49 AM, avguytx said:

So is it an overkill to build cabinets out of Baltic Birch these days?  Is the $50 per sheet of 4 x 8 Oak or Birch ply from the bog box lumber stores going to suffice for most jobs?  I've seem some on here that appeared to have used it with decent results.

In case you do want Baltic Birch (now called Russian Birch) you can get it pretty close to where you are.  Acadian Wood Products in Little Rock stocks it.  They deliver it here to Russellville for me, but I am always buying a large number of sheets at a time.  The reason that they stock it, is because of Klipsch so would be the same stuff they use.

 

Bob Crites

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Yeah, I had talked to a guy there a few different times about it. Seems like he said the 4 x 8 sheets were the Appleply brand and they also had the 5 x 5 baltic/Russian. That big box stuff is ok for aome things but it's got lots of voids in it; Chinese stuff most likely. 

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thanks endo. I'm going to meet with a cabinet builder who's also an audiophile. he recommends using a certain plywood for the cabinet (to get the stiffness & density needed) & then doing a veneer of my choice for the finished look I'm after

I'll keep you all posted on my progress 

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