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JKent

Rectilinear XI

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Picked these up today--they will be a gift for a relative after the refurb.

The XI was the bottom of the line in 1971 at $80. Next step up was the Mini II at $100. The TOTL Model III Lowboy was $300. The XI is a simple 2-way bass reflex system with a 10" woofer and phenolic ring tweeter, crossed over at 1.8kHz. Freq response is reported to be 45-17k +/- 3db. The 10" Woofer W-11 was used in XI, XIa, XIb, XII. The 4" phenolic ring tweeter RT-11 was used only in XI. First impression: Nice speakers.

Like all Rectilinears these are well-built, but quirky. The cabinets are very solid and heavy with a nice walnut veneer. This pair is in good shape with only a slight seam opening and a couple of minor chips and scratches. The grille is a 2-layer affair, like many KLH models. Unlike most XI's I've seen discussed, these did not have a separate cloth over the tweeter. The grille frame appears to be beaverboard and it's impaled on half a dozen nails that protrude from the baffle. Those will go. The Alnico woofer has a cloth surround and 2-inch voice coil. I'll clean it up and use some of Roy's sealant on the surround. It is mounted to the baffle on threaded studs with hex nuts. The clearance is too tight to get a nut driver on them so the studs will go too. The metal basket seems like it could resonate so maybe some dynamat or similar is called for. Anyone have a good substitute for dynamat? The familiar phenolic ring tweeter is glued to the baffle. I'll use screws.

Because this is a bass reflex design there is a damping blanket stapled to the rear wall. It's some kind of crumbly insulation so that will be replaced with foam. In a recent bass-reflex project I used foam mattress topper from Walmart and it worked very well.

The xo consists of a big inductor (have not measured it yet), an 8.2uF PVC cap and a level control. Connection is made by way of binding posts that are adequate but not paced 3/4" on center to accept double banana plugs, so those will go too.

Won't be getting to this for a little while but just had to tear one open today! Will post more photos as they progress.

-Kent

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Great to see a new Rectilinear post here. For those that love the walnut boxes of the 60's and 70's, these are very good speakers that still seem to fly under the radar for the most part. Several years ago, I came upon an orphan XI, and since I did not have a matching pair, I gave it less attention than JKent is planning to do for his pair. A few pics of my lonely speaker are attached.

Very simple speakers, but still hard to fathom that these were the bottom of their line - - they are not tiny, are well-built, and perform equally well. Kent, all of your details do correspond with my literature as well, and it appears you may have 1970 models just like mine. Those fasteners are indeed weird - - - I encountered the same device with my first Mini III, and I made this comment in another post started by JKent:

"And just like an orphan Rectilinear XI that I have, the woofer is secured to the baffleboard with a rather odd fastener. No T-nuts and machine screws here - - - this device is basically a headed and threaded nail, punched thru from behind, with threads which accept a standard hex nut. This spike has a dangerous and sinister point which is no fun to work around."

(Blurry) pic of original crossover attached and yup, just a single 8.2uF cap and the inductor and the control. I think all I did was swap out the cap and spritz the tweeter control. You can see a heavy bead of silicone used to adhere the x-o panel, and this is the same adhesive used to secure the tweeter.

Two other points. My cabinet was stuffed with loose cotton batting with nothing stapled to rear wall. And the grille frame? I've never been exactly sure what is meant by "beaverboard", but I thought mine was 1/2" homasote - - - they may both be cellulose-based building boards by different names.

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Good clarification on the grille. After reading up on both products, it's probably Homasote. Wikipedia states:

Homasote is a brand name associated with the product generically known as cellulose based fiber wall board, which is similar in composition to papier-mache, made from recycled paper that is compressed under high temperature and pressure and held together with a glue. It is 1/2 inch thick and comes in sheets 4 by 8 feet.

Anyway--I don't much like it. I sprayed the grilles with Oxy-Clean upholstery cleaner, blotted and set them in the sun. The Homasote warped. It can be flattened back into shape but it's kind of crummy. But better than the Mini IIIs which I swear used shirt cardboard.

Other than that they are really well built. I did listen a bit but the conditions were not ideal--original caps, speakers on the floor. They sounded a bit tubby but my limited experience with bass reflex speakers suggest they need to be up off the floor.

I knocked out those threaded spikes and will most likely use "deep thread" screws from PE that I have on hand. Will use some 8uF Carli caps that are on hand and clean the pots (?) with de-ox-it.

I agree Rectilinears are good speakers that seem to go unnoticed. Probably should have kept the Mini IIIs (to give away). Here's a confession: I paid nearly the original retail price for the XIs, which is way more than they seem to go for but if they live up to their promise I think they will be well worth it.

-Kent

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I seem to remember that Homasote has always been manufactured in the one and only same factory since its inception, and methinks it's located somewhere in your state (NJ). I believe the primary ingredient is recycled newspapers. I found one reference that suggested that "beaver board" was a product made by Homasote, but who knows? It's a great product for some applications, but really terrible for this purpose. If your lumber yard stocks it, I'd suggest trying 1/4" MDF - - it's rigid but relatively lightweight and much easier on tools than hardboard.

After a closer look, the product might be closer to 7/16" thick, but the recessed lip (face of baffle board to outer face of speaker cabinet frame) on my XI is only 1/4", whereas on my Mini-III's this dimension is a full 3/8", enabling the fabric face to sit nearly flush with the cabinet face. Surprised to hear that you got the shirt cardboard - - - all of my Mini-III's have grille frames made of two layers of 1/8" tempered hardboard (masonite), which creates a very rigid panel.

Your speakers look like fine specimens, and it appears you might have the cotton stuffing, too - - - but how did some of it get adhered to the grille frame? I've never used any Dynamat, but I have read about attempts to use alternative materials for this purpose - - the one that comes to mind was a spray-on version of a rubberized tool grip product.

http://www.plastidip.com/home_solutions/Plasti_Dip

.....or maybe this?

http://www.spraydead.com/

Curious to know how you removed the pointed studs - - - I never like the combination of hammers and particle board, so hopefully you've found a gentler but equally persuasive method. The rest of your Rx for restoration sounds real good, too, but I flinched a bit when you got to the binding posts - - - is it really worth re-drilling the original crossover panel just to use the double bananas? :unsure:

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Thanks for the tip on MDF. I'll use that on the next set of grilles. For these I hope to use the originals.

That fluffy stuff apparently got out through the port even though the batt was stapled to the back wall. I think the foam is a better solution.

For the pointed studs I just tapped each with a small hammer. I agree about the perils but it wasn't a problem.

I found some "80 mil audio sound deadener" on ebay that seems to be generic dynamat so I may try that.

Not 100% sure about changing/re-spacing the binding posts but these are not "collectible" speakers that would be diminished in value by doing that. I would not put 5-way binding posts on AR-3s. We'll see how it goes.

-Kent

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Re-cap is complete. I used Carli 8uF + WIMA 0.22. Not necessary but I had them on hand.....

The old PVC caps were not bad. 8.2uF caps measured about 8.5 to 8.6uF. I did not bother to measure the inductors and Robert, you'll be happy to know I left the original binding posts.

The drivers got PE foam gaskets and were attached with PE "deep thread" screws.

The back and bottom of each box was lined with textured foam mattress topper from Wally World. Further damping achieved with "80 mil audio sound deadener" applied to woofer baskets. No points for appearance on that part of the job! ;)

Grilles came out pretty good--clean and flat. I'll use Velcro to attach them.

Still working on the finish. All I did was wipe them down with lacquer thinner, fill a couple of dings with epoxy and wipe on some Watco Danish Oil.

Photos to follow when finished.

Kent

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Looking good so far. Before you button them up for good, I'd be interested to see what you did to the woofer backside with the sound deadener. I like that textured foam, but will you be leaving the rest of the cabinet volume void? Since you are using coarse thread screws suitable for particle board, I assume you'll be rotating the woofer to bite into fresh 'wood'. And I guess the phenolic ring tweeter flange will require drilling. With ported speaker designs, I'm curious about the effectiveness of driver gaskets - - - does this added measure of air-tightness at the drivers ensure that the port will operate as intended ?

The various binding posts I've seen on early Rectilinear speakers aren't bad at all - - - at least they are threaded metal connectors and not the plastic spring-loaded type. On the crossover, did your speakers have something similar to the the red/black Callins/Temple caps like shown in post 2 (I was surprised to hear yours tested that close to original values)? When I saw your new caps, I first thought you were consciously trying to add a bypass cap, but then I realized you were primarily just wiring in parallel for additive value. But even though I'm not sure if or how bypass caps really work, your assembly appears to have covered this possibility as well.

Nice project, looking forward to the completed pics.

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Thanks ra.ra. You and I may be the only Rectilinear fans here (where's Joe Longwood?). Too bad--they're nice speakers.

To answer your questions, as best as I can;

  1. New photo in Post #6 shows the woofer.
  2. I don't know a great deal about ported speakers but in the ones I've seen the damping material is often just on the back, or even just thrown in the box. If I wer really serious about this I might experiment a bit.
  3. I filled the holes for the woofer mounts with epoxy, so there's plenty of bite.
  4. I wonder about driver gaskets in ported speakers too but it couldn't hurt. The particle board under the tweeter got kind of torn up when I pulled off the adhesive so the foam gasketing material helps fill some voids.
  5. I agree. The stock binding posts are fine. Not 3/4" o/c but they'll do.
  6. Yes--they had the Callins PVC caps and yes, I was surprised too.
  7. I agree re the bypass cap part and that is partly why I used the WIMA 0.22uF caps, although I'm certain I could not hear any "benefit" from bypassing. Also, I wanted to get rid of them because the leads are annoyingly short.

Some other random thoughts:

Rectilinear made some very well-constructed, good-looking and good-sounding speakers.

Their construction "idiosyncrasies" are annoying for restorers. Specifically

  1. Nailed-on grilles
  2. Homasote--it's too thick and too fragile
  3. Double-layer grille cloth. Probably not very transparent
  4. Glued-in tweeters. A pain to remove.
  5. Threaded "spikes" to mount woofers. No way to get a nut driver in there. A real PITA.

Those nits aside, these are nice speakers and it's hard to believe they were bottom-of-the-line. I really like the real wood veneer and the quality of all the components. No corners were cut apparently.

Like other ported speakers in my admittedly limited experience, these do NOT sound good if they are placed on the floor. They DO sound very good when they are off the floor. I'll be doing some more listening with them on stands (well, on top of other speakers) and report back.

Kent

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Well. they're finished. I did a listening test and with them off the floor they sound really good. I don't have all the vocabulary for describing the "sound" of any given component but these had good detail and everything sounded right. Rectilinear wrote in their ad for the XI that they had paid a lot of attention to the crossover, to get the midrange right and I can say that vocals sounded very good indeed.

Here are a couple of photos. I didn't sand these. The cabinets were in generally very good condition for being over 4 decades old but there are a few surface scratches. Let's call it "patina." Two coats of Watco Danish Oil (Dark Walnut) and they look fine. One logo is missing. SN on one is 106179. Other SN is missing.

The grilles stuck out a bit beyond the frame to begin with and the addition of Velcro makes them protrude a bit more. Trouble is the adhesive on the Velcro has pulled off a layer of the Homosote in a couple of spots so I had to re-glue them and add staples. We'll see if those hold but pulling the grilles off could be a problem..

Hope my niece wants these. I have too many speakers and not enough space!

Kent

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As with all of your projects, another very fine restoration and terrific documentation, and I fully agree with all of your decisions and assessments noted here. Not altogether unlike an AR-4 or 4x or EPI-100, this is a really terrific, robust, simple, entry-level two-way "bookshelf" speaker (albeit with a 10" woof!).

No need to go wild on the cabinets, in spite of the fact that Rectilinears seem to have a pretty substantial veneer. IMO, when the veneer is largely intact, some scratches, scrapes or minor gouges do not necessarily detract from the beauty of the cabinet - - - in fact, imperfections often contribute to the character of a 40 year-old product. I have become enamored with Howard's RAF in the mahogany flavor, as it sometimes adds a very subtle reddish tone that I think brings renewed life to the walnut.

I'm totally with you about not being able to describe audible characteristics with words - - - I have lamented my own inadequacy more than once on these pages - - - but it is nonetheless interesting to hear your perceptions of the importance of ported speaker placements.

About your rants.....

  1. Nailed-on grilles. Couldn't agree more, short-sighted idea.
  2. Homasote--it's too thick and too fragile. Great product for other uses, but a terrible material for grille frames.
  3. Double-layer grille cloth. Probably not very transparent. Probably correct about transparency issue, but it's even more redundant since the outer cloth is often dark. Compare this to (light-colored) AR-2ax grilles which are almost always unattractively revealing their driver cut-outs.
  4. Glued-in tweeters. A pain to remove. Yep, but as much as I enjoy dis-assembly, I just leave them in place.
  5. Threaded "spikes" to mount woofers. No way to get a nut driver in there. A real PITA. Just a bad idea.

Another fine restoration, good for a new generation. Me hopes your niece appreciates and enjoys.

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well there is at least one other Rectilinear fan here to chime in. Nice restore once again! I hope they find a happy home. My highboys had decent speaker wire posts, although I did replace them. The whole Rectilinear line looks like it was pretty solid.

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well there is at least one other Rectilinear fan here to chime in. Nice restore once again! I hope they find a happy home. My highboys had decent speaker wire posts, although I did replace them. The whole Rectilinear line looks like it was pretty solid.

OOPS! No slight intended and thanks for the comment.

I have these temporarily set up in my rec room, maybe 2' off the floor and 3-4' away from the back wall. Listening to a variety of music I find myself switching to these instead of my reference speakers, the AR-3a's (on shelves). Would love to hear the highboys or lowboys.

Blasphemy? :unsure:

Kent

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Blasphemy? :unsure:

Just face the 3a's in the other direction so they don't witness this disturbing scene!

The highboys are a neat speaker, I think unlike most anything else in the number and arrangement of drivers (woofer, mid, 2 tweeters, 2 super tweeters). Of course the experts here can come up with other examples, I expect. By coincidence, they are also sharing my workspace with a pair of 3a's awaiting restore. It's a horrible space for acoustics, everything sounds middling, so I can't pass judgement on them yet. I should create a thread on the III's restoration, it is an interesting one.

Rectilinears come up on CL locally from time to time, but only the high/lowboys seem to get much interest. I'm glad you took these on, and better yet, find them so worthy.

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Likewise, me too, I'm pleased to see this level of appreciation for this model. As an entry level two-way bookshelf speaker, I suspect it was targeted to grab a share of the market that was dominated by the AR-4x and the EPI-100 (and probably some KLH models), even tho' the Rect. XI had a 10" woofer, larger cabinet, and ported design. While its sales never even approached either of the other two, I'd venture to say it would hold its own in a listening shoot-out.

Yep, the model III (tall or low) is indeed an interesting speaker, and at least two of us would enjoy the details of your restoration.

Curiously, I am currently reading Tom Wolfe's 25 year-old book, The Bonfires of the Vanities, and its central scene takes place on Bruckner Boulevard in the Bronx, the same street where Rectilinears were manufactured.

There were later versions XIa and XIb, but just in case you've not seen the original XI brochure (oops, there are three more pages to this literature - - - if interested, I'll add them, too).

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Tom Wolfe's 25 year-old book, The Bonfires of the Vanities, and its central scene takes place on Bruckner Boulevard in the Bronx, the same street where Rectilinears were manufactured.

Interesting. I thought you were mistaken because I know that at one time their address was 30 Main St., Brooklyn. But apparently they moved to the Bronx at some point. The reason I thought my niece might like these (aside from their sound) is she lived in Brooklyn before moving to the 'burbs and sometimes brought me Brooklyn-made treats.

there are three more pages to this literature - - - if interested, I'll add them, too

Please do!

-Kent

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JKent, turns out we're both right about the factory locations, and despite the two addresses, I'm inclined to believe your niece will appreciate these for several other reasons as well. This note from Wikipedia entry:

The first known main office location for the company (1966–68) was at 30 Main Street,Brooklyn, New York.[2] Some time around 1968, the company moved headquarters, manufacturing assembly, and service center to 107 Bruckner Blvd (E 133rd St.) in the Bronx.[3]The company remained at this address until it was shuttered in 1977-8.[4][5][6]

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

I'll add the other brochure pages to post 14, so they remain together in this thread.

Forgot to mention, but as much as I generally like this line of speakers, the use of Roman numerals for identifying purposes (can anyone say "Super Bowl"?) can be annoying. Seems as if AR and KLH had exhausted the more common Arabic numerals for their early models, and thus Rectilinear tried to drum up its own unique marketing ploy.

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Two more tangential thoughts for this thread.

Just to re-confirm the two Rectilinear factory locations, this first pic shows the rear tag on an early Mini III with the Brooklyn address.

And after closer inspection, I was reminded that my Rect XI woofers have dust caps not dissimilar from those on an AR-4x, which have transparent qualities that allow air to pass (see pic 2). Understandably, this may have different implications for bass reflex speakers as compared to acoustic suspension types, but still I wonder if this is typical for Rectilinears of this era. My list of models available in 1971 show four models as bass reflex (all 8 ohm) and two as acoustic suspension (both 4 ohm).

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My long-gone Mini IIIs also had the Brooklyn address. No address on the XIs. The XIs have the large transparent dust caps like yours. The Mini IIIs had flat felt non-transparent DCs.

-Kent

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Count me in as a Rectilinear fan and past owner of models III, Mini-III, XI and XIa. As a discerning, 16-year-old audiophile, I lusted after a pair of IIIs which were hopelessly too expensive. I used to annoy Crazy Eddie in Brooklyn at least once a month when I'd walk in and ask to hear the IIIs. He understood that I couldn't afford them, but let me listen anyway. When I finally bought a used pair many years later, I was very satisfied. The Mini-III, XI & XIa provided great sound & great value.

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I'm starting to get another Rectilinear project off the ground--this time the XIa. It was off to a rocky start but looks like it will work out. Will start a new thread when I have pictures.

Kent

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Great stuff J. Kent and looking forward to these next ones.

For whatever reason we just don't see Rectilinear speakers much out here in the west. I don't want to speak for others, but at least I don't. Same can be said with many of those other brands with their own sections here on the web site. My guess is distribution didn't always stray too far from the motherland which is the northeast?

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My guess is distribution didn't always stray too far from the motherland which is the northeast?

Yup. Brooklyn NY, later the Bronx.

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Yup. Brooklyn NY, later the Bronx.

All right well that does it! I am going to start a new web site devoted to the great old west coast speakers. Are there any? Ours out here would probably have less rot at least.

I guess I do have a pair of Speakerlab Model 2's that I am going to recap and see what I have.

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