First post: Questions regarding ALTEC 612 enclosure - DIY

[GM]

will also place the speaker opening in optimal position like on the 612C cab.

I just want to ask what parameters I have to take into account of making a stonehenge enclosure...

FWIW, acoustically, the theoretically optimal driver placement on acoustically small rectangular cabs is down from the inside top ~0.46233*height with the vent as close as practical, but there's so little difference no matter where the driver, vent is located that it's really a non issue except for how the room affects it, such as when the vent is on a different side from the driver.

Not sure what you're wanting to know other than what's on the drawing: http://www.lansingheritage.org/image...closures07.jpg

GM

[GM]

As I mentioned early on, I'm quite interested in this as well.
I had checked with GPA a couple months ago about the 9.0 CF tuned to 45.5 Hz or the 6.0 CF tuned to 53 Hz, and Bill told me that yes, the bigger cabinet plays a bit lower, but in his mind it wasn't worth the extra size the cabinets take up. I decided that I would try the 6 CF cabs and if I wasn't happy with the low end, I'd throw a sub in there.

Agree, though the reason to go big, preferably even bigger, is so that a ~Fs tuning combined with some room gain and maybe a bit of EQ gets you considerably more bass when it's on the recording and even more important IME, is its a more highly damped alignment, especially if a [ML]TL, i.e. doesn't have the thump/boom box 'West Coast' sound of a typical Altec alignment.

That said, in today's ultra wide BW, dynamic range 'world', a multiple subs system is required to allow a 604 or just about any woofer 'to be all it can be'.

GM

[Tralalalala]

Your Welcome ! It was my pleasure ! Hope your project comes out as planned.. Looking forward to your progress. What is your time frame like on building these ?

Time frame: have a lot to do before christmas... so need to stop the project until school has ended and the christmas holiday starts...

SO: will build the cabs between christmas eve and new years eve I guess...

[Tralalalala]

Yeah, these cabs were designed for back when a thumping 60-120 Hz was 'real' bass and 40 Hz was ~ -24 dB on all but the best RTR tapes. Then again, until recently, this [lack of] bass response is what you got at all but a few extravaganza concerts, so many vinyl, CD recordings are this limited also. Still, with a large, low tuned cab one can EQ a bit more bass out of them and also not lose as much on recordings with more low end.

GM

I listen to mainly vinyl on my vintage thorens record player with a 80?s Ortofon SPU.

SO: I guess these 612 DIY cabs will suit me quite well, I have mainly 50?s - 60?s jazz and classical + rock and singer songwriter until roughly 1975 in my record collection. Don?t have a cd player and don't have a DAC....

[Tralalalala]

Thanks for the effort!

I'm curious, if there's room for a 612, why isn't there room for a tall 612?

GM

Because I have gone quite far regarding this project by even buying these speakers...
I should be just be happy that I my girl even lets me build these DIY 612 cabs and place them in our apartment.

[Tralalalala]

Hi,

Here is two drawings of the missing brace that Altec Best was talking about.
I guess in a Altec 612 C cab it is very simple to integrate it in the enclosure (don?t need the cutout in the middle of it).
A little more effort, but still easy to get it to work in the DIY 612 cab.

Because of the minimal room this brace has in the DIY 612 cab will it cause any problems for the bassport?






- tralalalala

[GM]

Because I have gone quite far regarding this project by even buying these speakers...
I should be just be happy that I my girl even lets me build these DIY 612 cabs and place them in our apartment.

I guess by happy accident I've always avoided these types of issues since I've always had huge speakers, so they were always part of the 'package'. Frankly, they all liked how they performed their music to the point of bragging about them to their friends, relatives, so we had a semi-constant flow of folks over for an audition.

GM

[Tralalalala]

Hi ,

I have now probably used one and a half hour on net trying to find a 50 degree bevel router bit.
Nobody makes them. Or at least I cannot find any who does.

This made me think twice regarding my drawing that shows a bevel on 50 degrees for the Altec 604 E speaker.

Looked a second time on the mounting template earlier linked in this thread.
If the 604E is catergorized as an early 15" frame then the bolt circle is 14-9/16 instead of 14-3/4 as I thought.
This means that the CORRECT angle is 60 degrees. NOT 50 as previously posted.

And yes they do make 60 degree bit heads .... ; )

I also wanted to tell that I?m quite sure that I will not build the front panel with the round edge, this is because I then have to buy three plates of birch x-finer instead of two. maybe at a later date I will buy a third plate for this project, but not right now - since I want to have the possibility to do so I will place the speaker in the position shown in the 612 DIY cab, not as in the 612C.


- tralalalala

[Tralalalala]

Hello again !

I have not forgotten this tread

I have not started building the speaker enclosures, but will soon !
This is also why I have not posted any new messages....


Anyway: I?m a bit confused regarding the baffle opening.

This is what I do not understand:

1. The 612C cabinet blueprint has a baffle opening of 14 1/8 ". If I have understood this correctly the 612C cabinet is a cabinet built for (among others ) the 604E speaker.

2. When I look at the data sheet for the 604 E speakers the cutout ( baffle opening ) is set to 13 1/4 ".

This is how I see it now... and I?m confused which one that is correct. maybe both... I do not know....


- tralalalala

[Altec Best]

The 612C baffle is designed for a 16" frame front mount.The original 612 cabinet baffle that you wanted to use is for a 15" frame rear mount. IIRC.