Altec 606-Inspired Build Using A-7 Components

[Denten]

Thanks, Denton!

Just a few rough first impressions of these speakers and my listening experience last night: I hate to use a word like "amazing," but that's the way I feel about the bass response of these cabs. Most specifically, the linearity of the response. It's been the experience of all of us, I'm sure, to notice that - whether due to room placement or the design of the speaker - certain notes of the response have a tendency to punch hard and loud compared to the remainder of the bass frequencies. Placed where they are, with no nearby room boundaries, these exhibit none of that. From the highest bass notes to the lowest, the bass response is uniform. I have bass in abundance, and of the exact quality that I've always wanted. I hope that the RTA will confirm my impressions, and that once placed in my room that quality remains true.

The horns are delicious, and sound completely different than they did when I initially tested them as they simply lay on top of the cabinets with foam to support them. In the initial test I was happy with them, but installing them in the cabinets with anchoring and voluminous and heavy foam stuffing has transformed the sound quality. There is a total lack of any hint at "horniness" or ringing - just a pure reproduction of what is fed to them. With one exception - the UHF.

Though the HF content is quite nice as is, it is easy to hear that they are rolling off fast above 10-12Khz. And I could easily live with them just as they are. But I'm one of those who really enjoys the "air" and crispness that good UHF extension gives. Temporarily adding the Beyma super tweets with a simple 1st order crossover at +/- 10Khz positively transformed the presentation to a true full-range experience. When I do a video of these speakers, I'll try to remember to record them with and without the super tweeter so that you can hear for yourselves what I mean. I want to hear your opinion.

So, I'm going to do some extended listening with the super tweets in their boxes sitting on top of the enclosures. That way, I can play with the positioning. I want to determine if any time-alignment issues arise with the tweeters at the very front of the cabinet. If the sound remains pleasing with that positioning, I'm going to complete this project by installing the super tweets in the motor boards, just above the woofers. I hope things will work well with this positioning, as installing the super tweets behind the grill will vastly improve the visual presentation, and will eliminate the unsightly tweet boxes from their perch on top of the enclosures.

Hope to finalize all this by Saturday or Sunday, then move the speaks into the house where I can begin dialing everything in. I'm very enthused and happy with what all this labor and time has wrought. Almost giddy looking forward to see what improvements I can wring out of these speakers - and braced to endure the fetching Mrs. GeeDeeEmm's complaints about how big and imposing these things are.

It's time for some music appreciation exercises!

More to come. Thanks so much for your support and encouragement, guys.

GeeDeeEmm

I wish you lived closer, I'd love to hear them in person. ................well I could be there in about 17 h and 53 min.

 

[gdmoore28]

I wish you lived closer, I'd love to hear them in person. ................well I could be there in about 17 h and 53 min.

Come on, my friend. I'll be happy to keep you in the warm and friendly lap of southern hospitality, along with traditional southern meals with fried potatoes, fried okra, ripe tomatoes, and cornbread. Or, if that's a little too rich for you, we'll just burn a couple of steaks accompanied by a baked potato and a piece of garlic bread dripping in real butter. Then, we'll go for a run - to the porch swing with another glass of sweetened iced tea.

Better hurry, though - summer's disappearing!

GeeDeeEmm

 

[fredgarvin]

A very nice thread, I've been following. Those Altecs look beautiful. I too have a question about the adequacy of a 2 way design, having non-stop tinnitus myself. Yes, also a former drummer and guitar player since childhood. I'm very happy with my Quartets-3 ways- but perhaps I'll stumble into a project myself some day.

 

[gdmoore28]

Those Altecs look beautiful . . . perhaps I'll stumble into a project myself some day.

Thanks, Fred!

I feel a bit lost now that these are essentially finished. I have a couple of 7 cu. ft. cabinets that I happened upon too cheaply to be ignored. So, maybe . . . .

Considering the fun element, you simply must find a project.

GeeDeeEmm

 

[doctorolds]

Simply outstanding GD! The vision, perseverance, and final completion of a wonderful project. Thanks so much for sharing your journey with us.

I was wondering what your thoughts are now after spending a few weeks with them.

 

[gdmoore28]

Doc,
I've hesitated answering your question for a few days because, frankly, I don't know what to say. Can I really be objective with something I've put so much effort and time into? Have I really been exposed to enough state of the art equipment by which to judge? How does one fairly criticise one's own creation?

Aw, enough with that nonsense - they sound phenomenal. Really. And I'm sure that a true audiophile with golden ears could tear them apart, but they are the first speakers I've built that meet and exceed my every desire in a speaker. There. I've said it.

If it could ever be said that an idiot turned loose with some wood and some basic (very basic) knowledge of speaker building would come up with a killer speaker, it happened this time. And I think it comes down to simply using very old - but very good - components and stealing ideas from everybody who knows anything about Altec products.

The horns are incredibly immersive (here we go . . . .) and make the vocals sound immediate and . . . dare I say? . . . realistic. Extreme damping in the horn box seems to have eliminated any "horniness" at all. How can a horn sound warm, up close, and personal? But it does. And that heavy little Beyma super tweeter is just wonderful, with zero harshness or overbearing presence. (I have both the 802 and the Beyma dialed back approximately half way on the L-pads, and they blend seamlessly.)

The bass enclosure is what thrills me most of all. I submitted the dimensions and the TS parameters of the 416 woofer to a top notch designer on the Parts Express Tech Talk forum, and he was overly kind to specify my port dimensions. I think he nailed it, too. This is the first speaker I've built that has equal levels of clean, clear bass from top to bottom. Zero boominess. It just seems real, honest, and un-manipulated.

I know that once I get around to actually measuring these things on an RTA I'm going to be embarrassed by my syrupy description of what I'm hearing, but for now I'm just loving it. I'm happy and proud of what resulted from this project. And a bit ashamed for being so ebullient in my description. But, for now, I'm a school boy with his first love. I'll have to chime in again once the warts and pms begin to show.

GeeDeeEmm

 

[doctorolds]

Wow GD, you had worried for a second there. Phenomenal, that is what I was hoping for. I am glad they meet your expectations and you should be proud of what you have accomplished, from both an appearance and sound standpoint. Since their sound quality is meeting your expectations it really doesn't matter what others think or the RTA tells you. Maybe one of these days I can find the time to come down your way and see for myself, if you'll have me that is. Enjoy, you deserve it.

 

[gdmoore28]

Wow GD, you had worried for a second there. Phenomenal, that is what I was hoping for. I am glad they meet your expectations and you should be proud of what you have accomplished, from both an appearance and sound standpoint. Since their sound quality is meeting your expectations it really doesn't matter what others think or the RTA tells you. Maybe one of these days I can find the time to come down your way and see for myself, if you'll have me that is. Enjoy, you deserve it.

You are more than welcome, good sir. You know what kind of Arkansas hospitality to expect. Let me know any time you are in the area.
GeeDeeEmm

 

[BillWojo]

I bet they not only sound sweet but they look beautiful as well. I followed this thread from the beginning and am very impressed with the work that you did. You should be very proud.
By the way, how is your hand?

BillWojo

 

[gdmoore28]

I bet they not only sound sweet but they look beautiful as well. I followed this thread from the beginning and am very impressed with the work that you did. You should be very proud.
By the way, how is your hand?

BillWojo

Thanks so much, Bill. I'm humbled. And thanks for asking about my hand. It's all healed with a nice little scar to remind me about my mistake!

My wife and I just got back from having crab legs with my beloved oldest son and his family. Man - family is such a blessing - most of the time. Anyway, the wife stayed over to watch the latest episodes of the Walking Dead, so I'm sitting here with my Chiquaqua and getting in a few solitary moments listening to Regina Spektor's "Remember Us To Life" CD. If you like female vocalists with a cool, twisted songwriting talent, check her out. She has three songs on this album that just slay me: Grand Hotel; Small Bill$; The Trapper And The Furrier. Wow. That is songwriting. The rest of the songs are good, but these are killers.And the album is well recorded, too.

GeeDeeEmm

 

[EarlK]

Great Thread GDM !!

Thanks a lot for chronicling your journey to Altec bliss.

I know that I get a lot out of seeing how others do things ( & then wondering if I could do it in a similar manner > usually not ).

( About those measurements ) you know, at our ( the collectives ) average age, a view from the RTA really needs to be gracefully accepted as yet another reflection of our failing faculties ( or something like that ).

Table-saws give me the willies ( even when professionally setup ).
- I used to store my gear at a set-shop years back and had full access ( at off hours ) to their gear ( I was mostly successful at not hurting myself / though I've had some pretty severe kick-backs ).
- Your "push-stick" story really brought it all home for me just how lucky I've been .

 

[Jbl Joe]

This is going to be as close as one can get to a "budget" Altec build considering the skyrocketing prices of classic Altec components. Like a lot of you guys and gals, I have little to no money to throw at these pieces, and the process of assembling them has taken three years of swapping and watching for good buys. I'll summarize for those that are interested.

The cabinets will be based on the Altec 606 corner cabinet: http://lansingheritage.org/images/altec/plans/1960's-lf-design/page15.jpg
This cabinet was chosen for a simple reason: I don't have space for anything larger.

Finding the Components (Skip this part if you like. It's just background info.)

I've been entranced by the look of the Altec 811/511 horns since I was a kid in the late fifties. So, yeah, this build is based a lot on nostalgia as much as anything else. But how to afford the components? I was fortunate to be good friends with an aging WWII vet and electronics technician in town and made sure that he knew where to sell his old vintage gear when he was ready. Shortly before his passing, he made the move. I ended up with a University S6 cabinet, two University C15W woofers, two University HF206 super tweeters, two University N3 crossovers, one Altec N500 crossover, one green and one black Altec 511, one Altec 802D, and one Altec 808, along with assorted Altec mounting hardware. Most of this gear was still new in the original boxes.

In short, selling almost all of the above gear allowed me to finance the A-7 components. I found a matching 802D and 511 horn in green to match the one I had, and located a very nice pair of 416-8Z woofers. The woofers are the ones that have the 16" cast frame, along with the "A" model alnico magnets. I believe these were the standard woofers in the 846Bs.

View attachment 911767

The Cabinets

Having finally located a local source for 3/4" Baltic Birch plywood at prices that earthlings can afford, I was ready to start cutting lumber when I stumbled across a pair of (don't laugh, yet!) new kitchen corner cabinets at the Restore store in town. Whipping out my tape measure I found that the cabinets were within one inch of the measurements of the 606s. For $40 I couldn't see passing these up as a great foundation for what I was about to build. Yes, a few mods and much re-enforcement will follow.

It was first necessary to cut back the front of the cabinets so that the fronts would give me the necessary minimum 24" for the 511 horn width. Plans are to re-extend the front of the cabinets 5.5" in order to recoup the lost volume. Plus, this will be a much more interesting look.

View attachment 911770 View attachment 911771 View attachment 911772

(The joints in these cabinets were simply stapled together, so I knocked them all loose enough to fill the joints with Titebond wood glue. They were then clamped back together as the glue dried.)

These cabinets came with four 1/2" shelves, which I bonded to the top and bottom panels. This, of course, yielded 1" thick panels. The side panels will be bonded to 3/4" Baltic Birch (for 1" side panels) which will extend 1" beyond the cabinet backs. Then, the same 3/4" BB plywood will be used to fabricate the back panels which will fit inside the recess. One of the back panels will be removable for service. More on this as I make progress.

I plan to make 5" risers under the enclosures, and these will be "kick-toed" back about an inch. Depending on how the calculations for volume work out, I may seal these risers and open them up for additional cabinet size. We'll see if it's needed.

I have a decent quantity of nice mahogany veneer that will eventually cover these, along with possible additional cabinet adornments courtesy of a local lumber reclaiming business. They frequently have a good volume of reclaimed cabinet trimmings from old homes that have been demolished. I love the look of fancy old cabinets, so maybe I can do that style here.

The Crossovers

This is the area that has given me the most headache so far. Even though I've been building speakers for over fifty years, I've always followed somebody else's designs. So, outside of installing a standard Altec crossover, it was necessary to design something. I am not trained in electronics, so the last two years I've been immersing myself in learning about crossover design, speaker measurement, yadda, yadda.

In the end, I've decided to start simply and modify as I have access to diagnostic equipment. So, for now, I'm going to use a simple second-order Linkwitz-Riley crossed at 800Hz, followed by the sixteen-ohm version of the Altec 30923 eq/attenuation circuit. As typical, my first intention was to use air-core inductors. Then, I ran across a fellow on ebay who builds really nice iron core versions from 14 guage windings and DCR readings on par with typical air cores. So, that's what I went with. The capacitors are motor start caps. Why? Because I've read good reports about them and (I'm ashamed to say) I dig the way they look. Sort of a Klipsch look. Here's what I came up with:

View attachment 911779 View attachment 911780

More later. I'm old and my back is hurting.
Comments are quite welcome.

GeeDeeEmm

Those are cool. I'm more of a Model 14 15 and 19 guy. Have Flamingos my dad bought new in 66

 

[Altec]

FAIT ACCOMPLI !!!
In the next few days I'll hook up my RTA and get a look at exactly what these are doing.

Greets!

Found this while Googling for something else; quite impressive! Better than some Factory cabs; love the grill work/attention to detail, got more patience than I'll ever have. Any idea when you can get around to measurements?

GM

 

[gdmoore28]

Thanks, GM!

The cabinets are 48" tall; 37" wide at their widest point; and 24" deep. They are under 250 pounds each.

GeeDeeEmm

 

[Altec]

You're welcome! Thanks, nice n' heavy like I prefer, though I was referring to the RTA, etc., measurements you mentioned.

GM

 

[gdmoore28]

You're welcome! Thanks, nice n' heavy like I prefer, though I was referring to the RTA, etc., measurements you mentioned.

GM

Oh, ok. I misunderstood. I haven't performed any accurate measurements, yet - only cell phone applications. Those readouts looked way too good to be accurate. The only other measurement tool I have right now is the Behringer DEQ 2496 with a calibrated mic. As soon as I can pry myself off my lazy behind, I'll do some measuring and see what comes up. I'll post the readings here.

GeeDeeEmm

 

[Altec]

A couple up on me, my ancient dbx RTA, etc., system died ages ago and don't have a cellphone........ FWIW, REW is really popular on several major DIY sites, so lots of help if needed, etc., though haven't messed with it since for various reasons I still don't have a functioning stereo system: https://www.roomeqwizard.com/

GM