hello,
I received two empty 816A cabinets. In others times, I may reinstal products from GPA, but today specific order costs a lot considering each step from buying to door delivery.
I would like to find actual speakers with caracteristics close to original 816-8 or 515. I want to swap woofer without any adjustment as I can't do acoustics measures. I know it's not a cabinet for full range (100-1000Hz ?) but gently extending band will be nice.
thanks for advices.
I received two empty 816A cabinets. In others times, I may reinstal products from GPA, but today specific order costs a lot considering each step from buying to door delivery.
I would like to find actual speakers with caracteristics close to original 816-8 or 515. I want to swap woofer without any adjustment as I can't do acoustics measures. I know it's not a cabinet for full range (100-1000Hz ?) but gently extending band will be nice.
thanks for advices.
Hello,
Find a plan for this enclosure, create a hornresp model for it and simulate using as many driver as you want until you find the best option for you.
http://hornplans.free.fr/altec816.html
Find a plan for this enclosure, create a hornresp model for it and simulate using as many driver as you want until you find the best option for you.
http://hornplans.free.fr/altec816.html
816-8 ?? I assume you mean the 803/416 series. Note that specs changed over time even within a model # such as happened during the 416, 515 era, so assume best to choose based on the 416-8B, 515-8G with the former having a bit more mid bass output, which I've noticed some 'close enough' current drivers except with higher power handling, though didn't bother to save them.
It's my understanding though that Altec Renaissance has been actively 'switching over' from GPA's replicas now that it's been sold, so hopefully they can/will help you.
It's my understanding though that Altec Renaissance has been actively 'switching over' from GPA's replicas now that it's been sold, so hopefully they can/will help you.
@LORDSANSUI : "create a hornresp model for it and simulate using as many driver as you want until you find the best option for you."
My ascoustical knowledge is poor so I need ask for help.🙁
@GM : "best to choose based on the 416-8B, 515-8G"
Being a fan of ALTEC, ordering 416-8B, 515-8G is an evidence. But GPA have no resellers here and invidual order leed today to astronomical prices. So I need to find alternatives available in EU.
My ascoustical knowledge is poor so I need ask for help.🙁
@GM : "best to choose based on the 416-8B, 515-8G"
Being a fan of ALTEC, ordering 416-8B, 515-8G is an evidence. But GPA have no resellers here and invidual order leed today to astronomical prices. So I need to find alternatives available in EU.
As everything in life you can look to things as being simple or complex. In general if you looks as simple you gain confidence and move forward, so looking from this point of view.
Select one single driver, anyone from any brand. Start to design a vented box for IT. In hornresp you choose Nd type and you will play with just 4 parameters:
Vrc = Box volume
Vtc = box length
Ap = Vent cross sectional area
Lpt = vent length
Change one parameter each time and run the simulation, Other them see the Acoustic Power, export the data, compare the results in excell or the software REW (Room Eq WIzard), slowly you will learn how each parameter lead to the best curve you need.
So you can combine a Vented Box with a horn in front of the driver. In this case you need to change the design type in Hornresp from Nd to Compound (CH) and now you will have additional parameter to play:
Vrc = Box volume
Vtc = box lenght
Ap and Lpt = Will became H4 segment (S5 + S6 + it's lenght and shape)
And the front horn you can use up to 3 segments (H1 + H2 + H3)
If needed you can add also the throat chamber data.
The lest step, you will need a CAD software or Boxplan to draw your loundspeaker and and see what you can achieve as hornresp input from the "real" loundpeaker.
Select one single driver, anyone from any brand. Start to design a vented box for IT. In hornresp you choose Nd type and you will play with just 4 parameters:
Vrc = Box volume
Vtc = box length
Ap = Vent cross sectional area
Lpt = vent length
Change one parameter each time and run the simulation, Other them see the Acoustic Power, export the data, compare the results in excell or the software REW (Room Eq WIzard), slowly you will learn how each parameter lead to the best curve you need.
So you can combine a Vented Box with a horn in front of the driver. In this case you need to change the design type in Hornresp from Nd to Compound (CH) and now you will have additional parameter to play:
Vrc = Box volume
Vtc = box lenght
Ap and Lpt = Will became H4 segment (S5 + S6 + it's lenght and shape)
And the front horn you can use up to 3 segments (H1 + H2 + H3)
If needed you can add also the throat chamber data.
The lest step, you will need a CAD software or Boxplan to draw your loundspeaker and and see what you can achieve as hornresp input from the "real" loundpeaker.
I also share your approach, learn how to catch fish is better then only give one !
A soft to begin ?
Not easy to find modern equivalents, as you have likely found. For the 828 cabinet I like the Altec 416, as @GM points out. But maybe in that 816 abbreviated cabinet the 515 would be better. I think that is general what came in the 816 - maybe GM can conform. The choice is largely a question of bass extension vs efficiency and top end extension.
The Altec drivers were low Qts and low Fs, also low Xmax. That's not easy to find these days. @Cal Weldon as successfully used Selenium woofers in his A7 rig, so there is some leeway. How much to you want to pay for each woofer?
The Altec drivers were low Qts and low Fs, also low Xmax. That's not easy to find these days. @Cal Weldon as successfully used Selenium woofers in his A7 rig, so there is some leeway. How much to you want to pay for each woofer?
In the days drivers where interchanged a lot. If you use something with a low Qts (.3 or lower) and relative high Fs (like 50 Hz) with a hard suspension, light cone, strong magnet, this should basically work. The EVM 15B is a typical chassis for such horn/ reflex constructions, still available. Gauss, JBL and others where alternatives.
Do not expect deep bass from these, there is not much sub 70Hz. They give a very punchy, direkt hit live sound, but need something to deliver down to 35-40 Hz. Usually a 18" bass bin. Because of the low x-max of these drivers, you have to be carfull with equalizing and use a steep high pass to protect them.
On the top end large horns with compression drivers where used, x-over around 1000 Hz.
A large, heavy, loud midrange cabinet for a 3-4 way, part active PA set-up, mainly used indoors in not too large rooms.
Sensitivity is very high, more than 100dB 1W/1meter if I remember right.
JBL hat a more cube shaped alternative, called 4560, it had more low end with the same driver, but was larger.
Do not expect deep bass from these, there is not much sub 70Hz. They give a very punchy, direkt hit live sound, but need something to deliver down to 35-40 Hz. Usually a 18" bass bin. Because of the low x-max of these drivers, you have to be carfull with equalizing and use a steep high pass to protect them.
On the top end large horns with compression drivers where used, x-over around 1000 Hz.
A large, heavy, loud midrange cabinet for a 3-4 way, part active PA set-up, mainly used indoors in not too large rooms.
Sensitivity is very high, more than 100dB 1W/1meter if I remember right.
JBL hat a more cube shaped alternative, called 4560, it had more low end with the same driver, but was larger.
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Hello @altec9440 , I'm going to basically give you the fish, but it still need some small work from your side once it's DIY.
Attached you can find 3 *.txt files exported from hornresp using three mentioned driver. You can import them using hornresp import option run the simulation at your computer to see the differences. Note that the Eminence datasheet I found is 4ohm while the other two are 8ohm.
- Electro-Voice EVM-15L
- Eminence Kappa 15C (not celestion)
- Oberton 15L400
The input data from the simulation came from the CAD model I made based on the Altec 816 plan available at the website I mention in the post #2, so if your real loudspeaker has different dimensions, you will need to measure it and update the CAD model by yourself, witch is fully parametric and easy to change, it also has the ability to export a new hornresp model. This model was not yet published but if you need more information like how to use it, you can find in the link below. Use this file is hard as copy and past a file from PC to a flash drive, you just need to learn the steps.
https://freeloudspeakerplan.rf.gd/
Note: If you need very high accuracy, check all the information, mistakes can happen. If you just wanna to compare driver performance in the same box, you can accept some approximations as three parabolic flare I used in the horn replacing the curved surface. I'm not remembering if hornresp can generate this kind of flare with two parallel panels, if yes, it can be simplified to use one single segment H1, the results anyway, I think might be very close.
Attachments
I may add some vintage information from the time these where largely used, that may fit this vintage cabinet best.
These types of construction are not very driver dependent. Which made a whole lot of chassis possible candidates. The main difference, from using an Altec, JBL, EV or Gaus driver was price and max allowable input, making the SPL, which also needed the amplifier power. The resulting sound was not really different, as this is dictated by the construction. So choosing a driver, back in the days, was more based on budget and amplifier, as these where very expensive. No one would use a 2000 Watt amp on a 400Wrms speaker like today.
Imagine this low mid horn in a PA, playing with some 18" subs, a mid-high compression horn and an exponential tweeter on top. The result of an EVM 15B or EVM15L used in the single component would be inaudible. The "B" was considered more a horn, the "L" more a vented cabinet driver.
As this cabinet has a horn and a tuned vented (reflex) component, any speaker will be a compromise, as it is serving a horn and a vented cabinet.
You may have to realize that there is no chassis that turns this cabinet in a full range bass unit, seen by todays standard.
These types of construction are not very driver dependent. Which made a whole lot of chassis possible candidates. The main difference, from using an Altec, JBL, EV or Gaus driver was price and max allowable input, making the SPL, which also needed the amplifier power. The resulting sound was not really different, as this is dictated by the construction. So choosing a driver, back in the days, was more based on budget and amplifier, as these where very expensive. No one would use a 2000 Watt amp on a 400Wrms speaker like today.
Imagine this low mid horn in a PA, playing with some 18" subs, a mid-high compression horn and an exponential tweeter on top. The result of an EVM 15B or EVM15L used in the single component would be inaudible. The "B" was considered more a horn, the "L" more a vented cabinet driver.
As this cabinet has a horn and a tuned vented (reflex) component, any speaker will be a compromise, as it is serving a horn and a vented cabinet.
You may have to realize that there is no chassis that turns this cabinet in a full range bass unit, seen by todays standard.
People may think that sharing piece of knowledge is an ordinary act but sometimes, it's a good idea
to say how this help can be usefull. 😎
So thanks to people that that help to narrow searches combining 816 and drivers references
and thanks to people allowing to demistify parameters (still work to do !).
I"m trying to repair a pair of 6417RFE with 417-8H and T-50 University sound. I think to associate 816 cabinet with 6417rfe in order to add punch under 1000Hz...
to say how this help can be usefull. 😎
So thanks to people that that help to narrow searches combining 816 and drivers references
and thanks to people allowing to demistify parameters (still work to do !).
I"m trying to repair a pair of 6417RFE with 417-8H and T-50 University sound. I think to associate 816 cabinet with 6417rfe in order to add punch under 1000Hz...
Hrm, thought I posted this days ago. 🙁
The major 'stumbling block' by today's standards is a super high Vas, so must either use EQ and/or a higher Qts to compensate, which Altec did when phasing them out with the 3000 series drivers. Not to mention what happened to you with your GPA 416 rebuilds because Bill was working off the low output impedance (high DF) specs EV used for converting from the OEM's high output impedance tube era specs.
Originally the 816, 817 were listed with the 416 (better), 515 (best) and later only the various 515s. Note too that the 816 is tuned to ~62 Hz, 817/~52 Hz, so no need for a low Fs, so again, I've noticed there's some 'close enough' clones available, just at the time didn't see the point in keeping a record since I was trying to give GPA a 'fighting' chance in an ever tougher market.
The other variable is the desired upper mass corner tuning that the horn is designed for and have never bothered to figure them out as my version from way before these were offered used the 825/828 horn* as I learned the hard way that I couldn't tolerate the 'drumming' of my 210 horn's parallel walls (and never completely quelled them without modding the horn's output too much 🙁), so recommend building it with its 110 Hz expo flare, ~ 430 Hz throat (St) = ~194 Hz Fhm to find Qts' for a given Fs.
*Note how much difference there is between these horns response plots.
Fhm = 2*Fs/Qts'
Qts' = 2*Fs/Fhm
Qts' = Qts + any added series resistance [Rs]: http://www.mh-audio.nl/Calculators/newqts.html
The major 'stumbling block' by today's standards is a super high Vas, so must either use EQ and/or a higher Qts to compensate, which Altec did when phasing them out with the 3000 series drivers. Not to mention what happened to you with your GPA 416 rebuilds because Bill was working off the low output impedance (high DF) specs EV used for converting from the OEM's high output impedance tube era specs.
Originally the 816, 817 were listed with the 416 (better), 515 (best) and later only the various 515s. Note too that the 816 is tuned to ~62 Hz, 817/~52 Hz, so no need for a low Fs, so again, I've noticed there's some 'close enough' clones available, just at the time didn't see the point in keeping a record since I was trying to give GPA a 'fighting' chance in an ever tougher market.
The other variable is the desired upper mass corner tuning that the horn is designed for and have never bothered to figure them out as my version from way before these were offered used the 825/828 horn* as I learned the hard way that I couldn't tolerate the 'drumming' of my 210 horn's parallel walls (and never completely quelled them without modding the horn's output too much 🙁), so recommend building it with its 110 Hz expo flare, ~ 430 Hz throat (St) = ~194 Hz Fhm to find Qts' for a given Fs.
*Note how much difference there is between these horns response plots.
Fhm = 2*Fs/Qts'
Qts' = 2*Fs/Fhm
Qts' = Qts + any added series resistance [Rs]: http://www.mh-audio.nl/Calculators/newqts.html