Altec 817 / 817A cabinet plans ?

[Timelens]

I am halfway into building a pair of 817, my drivers are 416 8A. I have seen different plans but none is complete with all dimensions. Is there different cabinets for the 416 vs 515 ?
Is there anyone with a complete drawing ? the size of the opening at the speakers and reflex holes is a bit confusing... please help !

[RMC]

Welcome to LH.

I have the plans and the two versions of the 817 spec sheet. I don't have time right now, i will be back later tonight.

Richard

[RMC]

This is the official Altec 817 plans.

91067

Unfortunately the speaker mounting board info on the drawings has somewhat faded away, but the rest seems ok to read. Maybe the size of the speaker openings are on that mounting board info but its not clear for sure.

Some cabinet designs can be used with the same driver and for others its a different matter. Sometimes older Altec woofer spec sheets indicated in which cabinet(s) the driver would be a good fit physically and acoustically (See example only on the picture).

Richard

91068

[Timelens]

Thanks ! I miss the size of the side openings, the curved inner parts are already made. I suppose the width of the inner opening are important as well as the bass reflex.

[Timelens]

It says that 416 is ok for 816, I think 817 is kind of a double 816 ?

[RMC]

Timelens,

I had a look at other older Altec documents i have and didn't see the info you're missing. I guess you will have to figure it out. You can do a LH forum search on the 817 to see if other people might have posted that info.

I have a similar impression, 416 roughly comparable but for one woofer. However for the 816A cab its the 416-8C driver that is being specified. I don't recall seeing the A and B specified here, but they might be or work anyway.

Over the years the 416 has evolved from A version (yours), to B and C. Some driver T/S parameters may have changed a little, plus it seems that some tech info had errors that an Altec author corrected.

Are you thinking about changing cabinet from 817 to 816 or using some 816 info to help complete the 817 project?

Richard

[Timelens]

No, I already have the difficult parts made, the "wings" and it is just the outer box left. I am very focused at 817. I have been reading/asking a lot about 416 but so far my impression is that 416A has a different basket, B the newer basket and C is "not Alnico" ferrites but I am not sure. Different voice coils for more power also but basicly the same.
The French version has bass reflex opening under the horn as well and it might be possible to recalculate the area.
The French has an 190 mm mouth width inside the horn and I would really like to know if it is the same at 817, if I get that measurment right the reflex openings will automaticly be correct (I hope) so please look around for a original 817 and measure it ! There is not many 817 around in Sweden.

[Timelens]

I found one 816 drawing that specified 200 mm mouth width so 190 or 200 ?!
My plan is to change from Edgarhorns 80Hz to 817 and keeping the Altec 1503, it has the same width as 817 so it will look and sound good. Edgar has a single K130.
The bass is a pair of Jensen Imperial so 817 does not need to be working too low. I know 515 might be a better choise for 817 but I have four 416 already...
And yes I have a girlfriend :)

[macsic]

Hi,
Mine have 200 mm (+/- 2mm) for the mouth and for the vents 70x350mm x 4.
They have 416-16As. I believe that the 416A were no longer in production when the 817/816 boxes were introduced, hence the lack of a reference.

[Timelens]

Thanks a lot ! Nice to hear that 416 is working, I will complete the drawing and start looking for material. Unfortunatly we have a increase of wood prices by 400% but it will not stop me. I have great expectations for this speaker...

[RMC]

416-8A goes back to 1972 according to the spec sheet date, so Macsic is probably right about the A being discontinued when the cabs were introduced.

Richard

[Timelens]

Yes, it is probably so, I remember the Onken 360, It is supposed to use 416 8A but worked fine with all 416 even if Hiraga himself svore by 8A ...
I will start this project now and see and hear how it is like ! Thanks all for helping.

[macsic]

Hi,
I recovered the 817 which came from a Club in my region, they were equipped with PHL drivers and it is very heavy, I had to restore them but I like the result. For my use the 416s are better because they are more efficient and the former owner a sound engineer told me that 416s would do the trick and that the low frequency response would be even better than with 515s but you will need subs to dig more anyway. It's one of my systems on which I tinker, here is a recent photo but since then it has already changed a little bit, I know I'm a little crazy.
Have fun
91088

Thx Google translate...

[RMC]

@ macsic

Very nice group of boxes you have there!

@ timelens

One item i forgot to mention previously when you first asked questions, the one regarding the vents (bass reflex part of the cab).

Somewhat hidden in one of their technical papers i have Altec mentions that slot vents, like the ones on the 817, should not have proportions of more than 5:1 in terms of length vs width (JBL has something along these lines too as i recall). Altec doesn't explain why but loudspeaker building writer David Weems explains that long and narrow vents don't behave the same as others or normally. Hence why extreme proportions slot vents should be avoided.

Well, my reflex was to look at Macsic vent dimensions when he posted them in post # 9 and they do meet Altec's 5:1 proportions. So your best bet is to follow his: "for the vents 70x350mm x 4."

Richard

P.S. The type of frequency response front loaded LF horn cabs usually provide is similar to that shown on the picture (from JBL, in Eargle's Loudspeaker Handbook p. 210. Please don't repost on other site). Moreover, the 817 tech sheet does refer to that horn part as well as the reflex one. This is SR high output territory, not the land of the most linear response.

91089

[Timelens]

A very nice collection ! I wish I had that kind of mancave... I have not measured if it is possible to keep 200 mm AND 70 mm vent but since the outer box is not made yet I will adjust it to be correct if it is not adding up.

I see a Smith horn ? I have never heard one in real life, interesting ! I will pair the 817 with my dear Altec 1503 multicell but I would like to hear your impressions on the Smith horn.

[Timelens]

A problem comes with double 8 ohm, it will be 16 Ohm at the multicell and 4 in the bass cab. The crossover needs to be modified.
Macsic where did you put your crossover point ? I have now 500Hz 12 dB ( Hiraga A7) but thinking of a 6dB instead, any suggestions ?

[RMC]

What about connecting the woofers in series instead of paralell? Since this is a high efficiency cabinet it shouldn't require a lot of power to make noise, plus the cost of Watts is low. You need to match the LF/HF levels anyway.

6 DB for the low-pass (woofers) or on the high-pass side (horn) or for both sides?? Not clear to me the way its written. Assuming for both sides, the most critical would be the high-pass (HF) because of horn protection reasons. You would have to shift the xo frequency higher, like 1 khz, to have comparable CD protection.

Then the question becomes can the woofers meet properly the HF at 1 khz? According to Eargle a 15" can be taken to 1 khz with a DI 10 db. So a more directional driver, however the LF horn cab is already directional anyway, so some more or less might not spoil the sauce.

Richard

[Timelens]

yes, both sides 6dB slope but you are right, maybe to much HF is coming out of the 416 to keep the 288 safe ? I think 1000Hz would be waste of horn size :)
I have some alternatives for amps but I will start with LEAK TL12 at 12W . I have not yet tried biamp with passive filter but I feel it has to be identical amplifiers. I have tried electronic crossover but it all fell apart no more drama only HiFi.

I can see different opinions about serial connection and parallel, The impedance curve would look funny with 4 and 16 Ohm but if I use a tube amp it would be less sensitive I suppose ? the bigges part of the power is going to the bass bin and the horn only a fraction with its higher sensitivity ?

[macsic]

A very nice collection ! I wish I had that kind of mancave... I have not measured if it is possible to keep 200 mm AND 70 mm vent but since the outer box is not made yet I will adjust it to be correct if it is not adding up.

I see a Smith horn ? I have never heard one in real life, interesting ! I will pair the 817 with my dear Altec 1503 multicell but I would like to hear your impressions on the Smith horn.

Tell that to my wife ;-)
Yes, I have had a multitude of horns over the years but these remain my favorite with the 2450 equipped with aquapla slides, please note that this only involves me in a certain environment and yes it should not be overlooked that the horns must correspond to the needs and environments where they will be used. I'd say my other favorites have been 1005s (still have them) I've had 1003s that are too big for my use, the JBL 2360s are amazing too but they have to be in really big spaces the image forming a long way off ahead, the JBL 2395 lenses that I like just as much, of course I had the others with smaller motors but I definitely prefer the larger dia of the Altec 288 and the JBL aluminum or titanium aquaplas, I am intrigued by the M2s that I haven't really had the chance to fully listen to, there's not just one way to reach your goal. And blah blah

[macsic]

A problem comes with double 8 ohm, it will be 16 Ohm at the multicell and 4 in the bass cab. The crossover needs to be modified.
Macsic where did you put your crossover point ? I have now 500Hz 12 dB ( Hiraga A7) but thinking of a 6dB instead, any suggestions ?

In the past I've tinkered with my Hiraga inspired A7's and 5's but haven't used a passive crossover for these.
Last with an active DSP XTA crossover I always cut higher than 500 depending on the drivers it was around 650 with a first order slope but all this is in my opinion useless you have to take measurements
in your environment and then apply corrections and listen, try, listen, try, listen...
Crossover point for me now with my 817 it's LPF 800 with LR 48 and I don't know how it could help you :-)

[Timelens]

Yes,I realize that it will take som time to figure out and measure the crossover, it took me several years to tweak the Edgar/1505. I actually have 600Hz 12dB and I find it working well. I had the Hiraga correction for the multicell but it kind of took the breath of the horn, I have no audiophile words for it, just boring.
I guess 416 is a different animal than E130 but the crossover to the horn would be the same. I am thinking of borrowing electronic crossover just to find out the crossover point.
I find it useless running exclusive/expensive/rare triodes and then run it with a dozen of suspect opamps...
Thanks for input, great help !