New enclosure for M 19 components??

Hi there!
It seems to me it's time to start my new Altec project. For now I have two 811 horns and two 806A 16 omhs drivers. I don't have too much space in my room (it was the reason why I sold my Onken cabinets with 416A+511+808) and I need something like Stonehenge V enclosures, but for 811 horns and 15' LF speaker . Anyone can tell me if such design of the cabinet exist? I will need LF loudspeaker and I think 416-8C from GPA is a good choice? Btw, what is today's price of 416-8C? Thank you in advice for any possible help.
Mike

Yes - The SH V enclosure can be easily adapted for Model 19 components. Since it's the same internal volume, the performance should be identical, perhaps better.

And see if you can get Bill to make you some ALNICO 416's! If not, the C's will do nicely.

This thread is about an 811/416 loaded MLTL designed to be no wider than necessary to accommodate the M-19's horn/woofer offset. Anyway, contact him for any additional details and the now missing link to the rest of the pics: http://www.hostboard.com/forums/altec-users-board/125594-altec-project-done-thanks-gm.html#post1281213

http://img101.imagevenue.com/img.php...57_dan_si.jpeg

GM

Hi Todd and GM!
Thanks a lot for your reply and good ideas. Now I'm thinking what to do :) Stonehenge V is 9 cuft, but GM's cabinet is 10 cuft. SH V dimensions looks better to fit my room. On the other hand, GM's cabinet looks more closer to M 19 (just reversed W an D). What do you think if I'll use SH V dimensions and will put 811 horn inside the cabinet (on the top) and will make enclosure bit deeper (say, 22")? It will give me 11 cuft to compensate volume of the 811 horn.
Btw, I have a deal with Bill from GPA - I gonna bay two 416-16C speakers.

regards, Mike

GM, could you post a brief description of the way the transmission line is loaded? If there is a thread to this build, I haven't discovered it. I would like to build a taller M-19 enclosure, as well.

Quote:

---

Originally Posted by mikebond

Hi Todd and GM!
What do you think if I'll use SH V dimensions and will put 811 horn inside the cabinet (on the top) and will make enclosure bit deeper (say, 22")? It will give me 11 cuft to compensate volume of the 811 horn.

---

Greets!

You're welcome!

Yes, you can do that, though you may need to fine tune the vent depending on what the net Vb turns out to be, whether you put it up near the driver or down at the bottom and how the room's acoustics affects the speaker's response. Some fine tuning of the horn may be required also.

GM

Quote:

---

Originally Posted by westend9

GM, could you post a brief description of the way the transmission line is loaded? If there is a thread to this build, I haven't discovered it. I would like to build a taller M-19 enclosure, as well.

---

There are numerous threads on the DIYaudio boards about MLTLs, ML-horns and ML-TQWTs and a complete, mind numbing amount of in-depth info is available here: http://www.quarter-wave.com/

I linked to one example posted here, so not sure what you're looking for.

The short of it is that once the cab's length gets long enough to have 1/4 WL harmonics, they load (damp) the vent, making it more efficient which in turn allows it to either be shorter for a given area or a larger area for a given length. This results in better driver damping.

Anyway, the sky's the limit, so to speak, so what dims did you have in mind?

GM

Thanks, GM, that cleared up a lot for me. I've tried to digest most of MK's site, used it for speaker builds in the past. I don't use the Mathcad part of the information there as I only build the occasional enclosure.
My interest in a new Model 19 enclosure lies partly on the coondition of the cabs I presently have and listening space considerations. My present enclosures are a pair of DIY Model 19 clones. Although built to exact dimensions and sturdy, their outward appearance is less than desirable (tan Formica for the baffle). I would also like to raise the position of the woofer to get a better listening angle.
The enclosures that were linked to above have most of the requisite dimensions and woofer placement I'll need. I might change the depth in favor of width if that would be allowable. Also, if there is a way to raise the woofer even a bit higher but retain the MLTL characteristics, that might be the way for me to proceed. Perhaps a raised base would aid in that.
Thanks, again, for the original work done on the dimensions.

You're welcome!

Baffle width generally is only an issue if well away from any boundaries and usually can be tonally adjusted by careful balancing of the horn's output, so in this situation wider is better until at around 36" it becomes moot except in a truly large floor space.

Large cabs in general and MLTLs in particular have a high degree of tuning flexibility, so again, list the o.d. dims you want WRT the cab's H/W/D, center-line of woofer and horn to floor height and whether or not the horn will be in a separate cab, desired Fb (F6) and ideally where in the room they will be and how big/open a room it is.

GM

I plan to make a separate enclosure for the horn as I might change that in the future. At this point I find nothing objectionable to the 811 w/802 driver. If possible I would like the centerline of the woofer to be + 36" from the floor. In fact, +44" would be the most advantageous. The room these will be positoned in is 12' wide and 36' long. Speakers positioned on the short wall. Ceiling height is 9' but a vault is directly over the speakers. That vault height is 14'. I have no requirements as to the dimensions of the enclosure. My main focus is to build an enclosure that will afford the raising of the woofer.
In addition, I have other drivers like AMT1 tweeters and subwoofers that could augment any frequencies, if needed. I am currently biamping the model 19 components and see no reason to change to a passive crossover.

OK, to put the driver 44" off the floor I kept it simple by maintaining the M19's width/depth and pumping it up to 52.75" high when using 3/4" (19 mm) material, preferably 13 lam Baltic Birch or Apple ply. The cab's high damping allows the stock vent cutout to be used except horizontally oriented near the bottom to tune it to around Fs Vs the stocker's ~36 Hz. Due to the above average height and digital processing, placing the horn as close as practical to the woofer is best overall.

I forgot to ask which woofers you have, so note that due to the relatively large box volume (Vb) and long room, probably only 803s and early 416s will work well without some form of EQ to tonally balance them unless positioned in the corners. IOW just adjusting the separate amps levels might not be enough.

This large a cab requires significant bracing for it to 'be all it can be', but contrary to popular belief, high aspect ratio cabs don't require as much as the typical rectangular ones since it doesn't take much in the vertical plane, so typically some plywood scrap planks ~2/3 of the cab's internal height glued on edge along its length and offset in a golden or acoustic ratio normally suffices. Obviously the baffle's vertical stiffener must be in two parts, so a separate driver cradle incorporating an ability to slightly pre-load it once the driver's mounting hardware is snugged down to mass load it to become one with the cab for max practical acoustical-mechanical efficiency is desirable. The top and bottom take most of the acoustic loading, though due to a large cab's sheer weight and floor coupling, a second layer of plywood suffices on the bottom and I recommend adding either an 'X' brace or a couple of scrap planks glued on edge to the top plate. These plates have the side benefit of easily squaring up the cab. All that's left is to add interlocking bar bracing from scrap to tie all six sides together so that there's no way the cab can 'breathe' (flex).

Nowadays though, most folks 'kill three birds with one stone' by making a full height vertical front/back 'window' brace that is shaped to support the driver's motor and allow some shimming to apply a small amount of mass loading. Combined with either a full height one piece interlocking 'window' brace or two individual ones to tie all six sides together, you're done, though with this large a cab the added cost of the plywood is hard to justify unless the left over 'window panes' are large enough to use on one or more future planned projects.

Internal damping is a highly personal choice of trade-offs, so I recommend making the baffle in two parts with the bottom one removable and large enough to allow sufficient room to add/remove damping all the way to the top without removing the driver, plus it makes any vent tuning easier.

GM

Very nice, thank you. My material of choice for most recent builds has been Baltic Birch. The dust from MDF and the additional veneer step has moved me towards plywood. I believe the "window brace" is also the most elegant way to insure against flexing. I'll have to mull over the two-piece baffle. Another way to accomplish this might be to incorporate removable top and bottom. If the bottom and top are built with two layers of plywood in mind, it would be easy to do.
WRT the drivers, I have 416-8B's that are controlled by an active crossover with attenuation and CD compensation circuit.
The dimensions given, if external (and not allowing for driver and brace displacement) yield an interior volume of 14 3/4 cu. ft., if my calculations are correct. The tuning to Fs has really got my attention as another 10 hz lower than stock might make this an awesome build. Would two round ports of sufficient size with flared ends alter the tuning? The original rectangular vent opening is a cosmetic issue for me. Here, again, wisdom shows that a removable baffle would be advantageous to refine the final tuning and be able to define round port area and length.

As an aside,if the Polish princess had qualms about the original 19's, I can imagine her surprise to find these in her Throne Room. The good news is....no plants on top.

You're welcome!

FWIW, since the top, bottom are high pressure nodes, maintaining an airtight seal is mandatory, so best to seal them up good. That said, the shear weight of it will help to ensure a good seal on the bottom if a high quality gasket material such as industrial NEMA 4 (my preference) or at least 5-12 rated neoprene is used.

Hmm, I used the M19's nominal 30" W x 21" D and made it 52.75" H, so subtracting 1.5" from each should yield 51.25*28.5*19.5 = ~16.4827474 ft^3 minus the bracing, driver losses.

Due to the driver's high Vas combined with a large cab, other vent configurations will tend to be just different size areas and/or shapes unless an even lower tuning is used. The stocker's just happened to be a good one in a half space sim and easy enough to make. IOW to use flared vents with some depth will have to be very large in diameter, so dividing the vent into two triangles in the corners might be more visually appealing.

WRT plants, I often recommend heavy ones for mass loading smaller cabs that use ~full-range drivers or at least wide BW mid-bass drivers. Folks think I'm spouting an 'audiophool' tweak until they try it and hear how much it positively affects its performance. These will be massive/rigid enough to not need any additional weight to anchor them to the floor though.

Anyway, here's half space sims of the M-19, your tall variant and a 24" deep (o.d) variant that pumps it up to ~19 ft^3, so we see the M-19's 'bump' in the response that causes the 'West Coast Sound' and the two larger cab's lower tuning having a more accurate sound to a lower frequency with the largest cab apparently having only a minuscule amount of extra box efficiency, so not worth the extra wood unless a lossy passive XO and/or a high output impedance amp is used.


GM

Thanks again, GM.
Perhaps I'm missing something but I measure the external depth of the clones I have as 19" depth. The Model 19 plans at J. Markwart's site, here: http://home.earthlink.net/~jmarkwart...es/model19.pdf also show that dimension.
Using the same dimensions you've listed for height (51.25 internal) and width (28.5 internal) but using 17.5" as the internal dimension of depth, I calculate 14.792 cubic feet of volume. Would this volume be correct? If so, does that greatly alter the tuning of the cab?

Your attachment of the sims does not seem to show up in my browser. I could probably extrapolate the different responses of the different volumes if I had a couple of graphs.

I will forgo the flared port idea for the present. Your idea of triangular vents appeals to me.

Unfortunately, my bride also operates in the plant kingdom under her true identity, Dr. Plantvorkian. There is nothing appealing about the type of vegetation that would be present on top of the enclosures, except for the mass-loading effect.

You're welcome!

"What we have here is a failure to communicate." :eek:

I said 'nominal' dims, i.e. includes the grill since you said that size didn't matter just so long as the woofers were high up enough. ;)

Anyway, it's enough of a reduction to raise the predicted F3, Fb from the high 20s to the low 30s, though in the scheme of things it might only be noticed with organ music or some movie's special effects at relatively high SPL in the form of an audible flattening of the 'notes' due to the woofer's VCs moving too far out of their magnetic fields, i.e. the eufonic soft clipping AlNiCo's famous for.

Oh well, you could always buy some nice plants for one of the female centric holidays or replace inexpensive ones on each holiday if she has a 'brown thumb' (been there, done that).

Yeah, apparently our attachments haven't made the move to a new server yet (ever?), so here it is again, though with the original larger, lower tuned M-19 'long':

GM

Comparison of the original and reduced Vb variant attached. The latter could be tuned lower to match the original's Fb, but the F3 would be higher, i.e. 'faster' roll off below ~100 Hz which may, may not be better in-room and why I always recommend the biggest tolerable box and experiment with vent tuning for best in-room performance which BTW can mean that each cab is tuned differently. This is really highlighted when using vented alignments for surround sound or multiple sub systems, even some vented and others sealed can be required.

GM

Well, isn't that special........ it says I'm 13 Kb over my total upload limit, so can't upload it! Is this a great hostboard or what? Seems like it's way past time to become separate forum tab on an audio and/or HT forum if costs are comparable.

GM-
The last two posts have cleared up the volume questions and added to my understanding of vents and box tuning. Thank you very much.

I'm in agreement about sizing the box to the largest possible volume. No sense leaving anything out of the presentation, if possible.

WRT herbaceous material, I've learned to just look the other way. There have been too many casualties to enjoy indoor plants. At this point, I believe she might be able to ruin the artificial varieties.=)
She does enough other good things connected to my life that planticide is forgiven.

Quote:

---

Originally Posted by GM

...Well, isn't that special........

---

Chuckle...ya got that right. One or two cellphone quality pics, and you get the old ruler 'cross the knuckles. Still no limit for anything that's already on the web... for now. I won't be wasting many images that are just as likely to evaporate as the old ones did though. Lesson learned. :(

Yeah, I loaded the sims here: http://www.flickr.com/photos/515b/

GM

This is another implementation of a larger box for the 416-8B: ALtec Model 19-XO upgrade discussion - Page 9 - Lansing Heritage Forums post #126. The designer comments on cabinet size in post # 129.

I will have some shop-time this week and into the weekend so will be able to make some progress as to the larger, longer enclosure.
Thanks, again for the sims, GM. I hope my efforts are worthy of your help.

Greetings GM and all!
Thanks for very helpful information! I have decided not to limit to components from ? 19 and I have bought on ebay a pair of 414z woofers. Also I was lucky to buy on ebay minty pair of 416z woofers. I hope to make loudspeakers with the better midrange, rather than ? 19 have. Now I need to solve how to connect woofers. Do I need to use 3-way system, or it's better to connect woofers in parallel in a 2,5 configuration? Whether it is necessary to do the closed box for 414z inside the main enclosure ?
As to 806? driver with 811 horn, my measurements of their frequency response have a little disappointed me. Even with the T-filter the frequency response is not too good on VHF. Now I'm thinking about using a super tweeter.

Regards, Mike

This gentleman has used the 416z and the 811 with 804 and 802 drivers to satisfaction. He also augments the UHF with an Altec 3000:http://members.myactv.net/~je2a3/speakers2.htm.

I am also using 802 drivers with the 811 horns. I've used Heil AMT tweeters to augment the high end but have found that the 802, combined with an active crossover w/ CD compensation, sounds good to me without the augmentation. I will be experimenting further after the enclosure change and positioning them in their final configuration.

Quote:

---

Originally Posted by mikebond

Thanks........

Do I need to use 3-way system.....?

......closed box for 414z....... ?

---

Greets!

You're welcome!

Three way.

Sealed.

Yeah, 806s are a bit weak on the top end, so either a super tweeter or switching to an 802-8G or 900 series is required along with CD EQ.

Anyway, here's the Japan spec 9862 studio monitor with a 414/416 combo, though with a special horn and super tweeter:

http://www.fsinet.or.jp/~ash-k/ALTEC/9862.jpg
http://www.fsinet.or.jp/~ash-k/ALTEC/9862-2.jpg
http://www.flickr.com/photos/515b/3256772729
http://www.flickr.com/photos/515b/3256772799


GM

I wonder what the crossover points are on that Japanese market speaker? Also... would the horn out of a Model 14 suffice as a replacement for that Japanese market horn?

I looked at these a few years ago to possibly try and copy... but I am still trying to focus on my first current Altec project... as soon as I finsh getting the barn cleaned out at the new house...

Either a dual 416 Model 19 variant or one of these... Not sure what will win out... :|

One more thing on that Japanese model speaker... I have to assume that the 414 is in a sealed enclosure internal t the overall cabinet.... Would anyone agree with that assumption?

Hmmmmmmnnnnnn.....

Sorry for the excessive posts... but with the Japanese market speaker design... using a removable front baffle... I could potentially build one pair of cabinets and mock up a similar 416/414 arrangement and then just build a new baffle for a dual 416 using the same shell... I may have to compromise on the overall dims, assuming I could correct with the porting.

So this may be a possible direction to go. Kill 2 birds...

Then if the dual 416 seems like a good idea, I could go forward with a full blown Model 19 variant...

What you guys think about such super tweeter in addition to 806a/811 ?
http://cgi.ebay.com/ws/eBayISAPI.dll...m=370146281986

Quote:

---

Originally Posted by mikebond

What you guys think about such super tweeter in addition to 806a/811 ?
http://cgi.ebay.com/ws/eBayISAPI.dll...m=370146281986

---

There a lot of folks trying to augment the 806's. A better solution might be to use a different driver on the 811. This a pretty extensive thread w/ measurements of the use of different drivers on the 811:http://audiokarma.org/forums/showthr...=147170&page=8. The consensus "best of the new" drivers, the BMS 4550 is available at a very high price here:http://www.lataudio.eu/HTMLs/DJ%20Se...20Frameset.htm . They do have the specifications and FR posted there.

Quote:

---

Originally Posted by mikebond

What you guys think about such super tweeter in addition to 806a/811 ?
http://cgi.ebay.com/ws/eBayISAPI.dll...m=370146281986

---

Bob's a reputable seller, but note that even he doesn't call them supertweeters. Also note that a statement of 'going out to 20khz' says nothing about how flat or smoothly they get there, or at what relative level. Even Altec used that old sales pitch. I'd be pretty surprised for any phenolic 'fram to go there satisfactorily.

Adding a tweet and even a simple XO usually adds as many problems as it solves. If you must go higher, replacing the 806 with something like 902s w/CD EQ, or the BMS (mylar 'fram) would be my pick.

Quote:

---

Originally Posted by Carl Bill

I wonder what the crossover points are on that Japanese market speaker? Also... would the horn out of a Model 14 suffice as a replacement for that Japanese market horn?

---

350 Hz
2.5 kHz
10 kHz

Not really, though it would work with a ~1.3 - 1.5 kHz XO, maybe even the M14's.

GM

Quote:

---

Originally Posted by Carl Bill

I have to assume that the 414 is in a sealed enclosure internal t the overall cabinet.... Would anyone agree with that assumption?

---

Seems reasonable to me. For sure it's what I'd do.

GM

Thanks GM. I appreciate the info.

I am ready for an Altec project... but the new (going on 3 years now :O) wife is keeping me busy with other "projects". :(

I should have the barn in shape for an Altec project by the end of the summer at the rate I am going. So I may be asking a lot of questions to get me pointed in the right direction.

If I ever figure out how to post pictures, I will post some of my projects over the last couple of years... non-Altec related, but still worth a look! ;)

Well, life got in the way and other interests were more compelling so I never got around to building the MLTL enclosures that were designed by GM, the" M19.longer" that was plotted and referenced previously.
I now have 6 sheets of birch ply in the shop and am about to embark on this build. I might post a build thread if there is interest. I've built a few pairs but am always open to learn new ways so post them tips and tricks, please.

To GM: Sorry about the delay in this but they will be built and measured.

Is there anything in particular I should know about the interior cabinet construction? I plan on using the double window pane method and the bracing ideas that were mentioned, previously. I would assume that no other baffles or bracing is required?

I've also been sorting out the front baffle design and will be building that with a detachable baffle on the bottom to access the inside and vary the vent opening, should that be necesary.

Thanks for all your help, so far. I hope my efforts are worthy.

Quote:

---

Originally Posted by westend9

I might post a build thread if there is interest.

---

Do you really have to ask? :D

Quote:

---

Originally Posted by Cal Weldon

Do you really have to ask? :D

---

Lol, I guess not. Heck, there are guys that want to see what I pull out of an old tube based console so interest maybe just as high as that.

I'll post up some links and a build thread when I have dust on the floor. I was thinking of starting today but heat and work drained me right out. The dew point was at record highs, today. 90 f. and dew point in the 80's, just freakin' miserable.