Cabinet and Crossover Design for 601C

[Drugolf]

Give me your thoughts. I just picked up a pair of Altec 601C with the 3000 Networks that I am really excited about. Once my Khorn build is done, I will probably postpone my other design and build efforts and focus on these.

I went looking for the 601 because I really am intrigued by the whole 604 thing. But my room really is more suited for the 12" version thus 601C.

For the most part the original altec design cabinets fitted with a 601 were the very low to the ground Monaco and LaPaz (end tables). I would like to do something along the lines of the 620 but scaled down for the 601. The 601's call for 3.5cf or so. Do I model a smaller version of the 620 with these t see what I get? Smaller will likely men some sort of legs or feet so I can get the driver up close to listening position height or slightly below.

I was also working on an Onken build that I suppose in the petite size might work with the 601C, although would still be a little low at about 21" to center of driver. Plus, if it ends up not being a good combo, I can always use the Onken with the 414's I have and horn.

I don't mind going with a bigger cabinet. It looks like the Stonehenge I has a 12" driver and of course the 9849, but it is still a shorty. I would like to stick with some golden ration dimensions if I can.

 

[Katalyst]

Do you have a DATS system to get the parameters ? This is an option . Onken for Altec Lansing 601C

 

[Drugolf]

Do you have a DATS system to get the parameters ? This is an option . Onken for Altec Lansing 601C

I do and will test them when they arrive. With duplex or coax like these, do I needed to test it isolating the woofer only somehow?

 

[Katalyst]

With duplex or coax like these, do I needed to test it isolating the woofer only somehow?

You can adjust the frequency upper and lower limits in DATS. The vas test is the one to get the box parameter. I use a roll of painter's tape. You will have to find something that clears the duplex .

 

[Drugolf]

We've been working through a petite onken design for these. Considering the 601 is basically the 414 the thought is this should be an applicable application. Plus, it would allow for potential 414 use as well as a vast number of other 12" vintage coaxials, full rangers etc that could be tried.

What you guys think?

 

[Drugolf]

One of the aspects I need to work out though is that with the petite, the woofer/tweeter will only be at about 22" high. this would work for use with just the woofer but might not be ideal for the 601 or others similar 12" drivers. I could build some pretty beefy sturdy block type risers for each corner to lift the speaker that would be removable when using them for the 414. Similar to those I've seen Kenrick use on many of his JBL's.

And good lord these will be heavy!

 

[electrovice]

The Altec 614 enclosure was the design recommended by Altec for the 601. The plans for the 1970's version of the enclosure can be easily found on the web. Complete plans for the 1940's version of the 614 with the "TV" front are another story. The precise dimensions for the port and for the face frame cut out are nowhere to be found ( I would love to be proven wrong). I have asked a number of eBay sellers to take a quick measurement of a vintage cabinet they are selling but have yet to get any results.

I have a pair of the 601-8d units with working tweeters that need enclosures. I have considered both the old 614 (I just really like the looks of it) or the mini Onken. My best estimate of the face frame cut out is that the width of the cut out seems to be the same as the diameter of the cut out for a 15 " woofer. The rest of the dimensions can be calculated and you would end up with an enclosure that is very close to Altec's original empirical design. Either of these enclosures would need some sort of riser to get the tweeters at the right height.

I am not sure that either of these will ever get built. I do not see the Mrs. being very enthusiastic about another pair of large speakers in the house.

 

[Drugolf]

Thanks Electrovoice.

There is course is a substantial difference in enclosure volume between the two options. I would much rather do something size wise like the 614, but do you get the most out of the bass with the volume only being slightly over 3cf? The petite is about 7CF.

Does anyone know what the 614 is tuned to?

 

[electrovice]

I cannot answer the tuning question. I am sure that the bass performance would be improved by using the larger cabinet. I have never heard the 601 series ever described as bass monsters under any circumstances. I have understood that their strength was more the midrange and higher frequencies. I have a small and fast MK sub that I could use to flesh out the bass if I went with the smaller enclosures.

 

[Katalyst]

Interesting stuff here. 1974 Enclosure Manual http://www.lansingheritage.org/images/altec/plans/1974-enc-design/page12.jpg

 

[Roscoe65]

I recall seeing something about the 9849 being tuned to 65hz. The 614 models out the same way. In any case there is only so much bass you’re going to get out of a 414. The 614’s wide baffle reinforces the midbass and it sounds full and very snappy. I’m pretty sure that you can get more bass from a petite Onken but I would rather let the driver do what it does best. They do need to be on short stands.

 

[electrovice]

A wild thought here. The Planet 10 HiFi guy, Dave Dlugos, designed an Onken derived design for the Goodmans 201 speaker. The Goodmans driver is an 12 inch woofer that was often paired with a center mount tweeter and sold in the US under the Lafayette or Allied name. This speaker would have been a competitor of the Altec 601 series. The link is to a thread in the DIY Audio forum about this enclosure. The enclosure is closer in volume to the Petite Onken but has a smaller footprint and places the centerline of the driver closer to ear level. Just a thought.

Goodmans Axiom 201 - Page 2 - diyAudio

 

[Roscoe65]

Interesting. Coincidently, I also own a pair of Lafayette/Goodmans Triaxiom 212 (Alnico). The factory enclosure recommendations are about 6 cubic feet vented or 4.5 cubic feet with the ARU aperiodic vent. The Goodmans is a very different driver than the Altec. They can both be used successfully in a 4.5 cubic foot cabinet, but the Goodmans requires a resistive vent and the Altec may not work with it. Of course, I could always build a 4.5 cu ft enclosure with removable baffles for each driver arrangement.

Over at TNT, Chris Templer asserts that the Goodmans 12” and Tannoy 12” work interchangeably in a modified Coral Beta rear horn enclosure. I don’t know if anyone has experience horn loading a 414, but I’ve only seen plans for vented enclosures.

 

[je2a3]

I don’t know if anyone has experience horn loading a 414, but I’ve only seen plans for vented enclosures.

I vaguely remember Joe Roberts mentioned listening to a scaled down VOT cabinet for the 414. But that's just partial horn loading + bass reflex.

 

[electrovice]

I have also seen the plans for that modified Coral Beta enclosure. I really like it.

I have two different pairs of the Lafayette/Goodmans speakers in my stash. One is the the SK216W and the other is the SK210. They are both triaxioms which have a center mounted horn tweeter. I believe the equivalent Goodmans woofers for these two are are the 612C for the former and either the 201 or the 212C for the latter. The speakers are related but are substantially different from each other. The same enclosures were recommended by Goodmans for the 201, the 212C and the 612c despite the great differences of the drivers. Sadly, much documentation for the Goodmans speakers was lost in a fire at the factory. Internet searches for info on vintage Goodmans speakers will find a lot of dead links.

Should this thread prompt anybody to look into Goodmans speakers from this era. Avoid the drivers with rubber surrounds. They don't age well. Anyone working with Goodmans speakers is pretty much blazing their own trail.

John

 

[Drugolf]

i mentioned having other 12" drivers to swap in and out. One such pair are Goodmans 412 Triaxioms.

I do believe in modifying previous designs that worked functionally to improve appearance, footprint, height etc, similar to my slightly modified A8. I will read up on the previous example you all identified above for sure.

 

[Drugolf]

Interesting stuff here. 1974 Enclosure Manual http://www.lansingheritage.org/images/altec/plans/1974-enc-design/page12.jpg

Yeah a good base line. Looks like for the 601 they like the 3.5 with regular port. Thus the 614 cab. Seems like with the 601, anything above the 3.5cf might provide limited return. Would like to get up to 5cf which seems like the magic number or most other 12" drivers.

What is that footnote about? 1/2" mounting baffle.

 

[Drugolf]

I recall seeing something about the 9849 being tuned to 65hz. The 614 models out the same way. In any case there is only so much bass you’re going to get out of a 414. The 614’s wide baffle reinforces the midbass and it sounds full and very snappy. I’m pretty sure that you can get more bass from a petite Onken but I would rather let the driver do what it does best. They do need to be on short stands.

Agreed. I do like the wider baffles. plus I am finding that deeper and narrow speakers are actually a little harder to fit in rooms that are on teh smaller side where shallow and wider do much better, like the 416 or my A8.

 

[electrovice]

I think the 1/2" baffle footnote only applies to the 405A which is a small diameter full range unit that is more for utility sound reproduction and not HiFi.

John

 

[gilmorneau]

I vaguely remember Joe Roberts mentioned listening to a scaled down VOT cabinet for the 414

Could this be in reference to the old Onken WB300? It was a scaled down version of an Altec 825 cabinet designed for Altec 414-8A.



The text reads: "Bass reflex speaker by Onken in 1968. It is derived from the Western Electric 825 speaker (the latter being very close to the voice of the Theater Altec 825). Dimensions 86 x 70 x 45 cm, it was made of Canadian plywood 25 mm thick. Reference WB300, it was equipped with an Onken 312 (prototype) speaker, close to the Altec 414 8A. Atop (the cabinet), the SC500W horn and the OS500MT compression driver."

Looks just like an Altec Voice of the Theater cabinet, but check the measurements--it's for a 12" woofer. I thought about building a pair but never got around to it. Of course. lol...