Dear friends. Please can anyone clarify for me what is the difference between Altec VOTT cabinets 825 and 828? I do have a plan of "named" 825 cabinet wich has a baffle width of 18inches, which did not achieve all the speakers width itself. Also I found at the web some DIY project which "has" the baffle width matching the internal cabinet dimension... I assume that the narrow baffle increases cabinet volume, so lower frequency shall be achieved...Please let me hear your thoughts and experiences on Altec VOTT, since I am planning to build a pair for me...Cheers. Marco - Brazil
Ignoring the various detail changes, the main changes are plywood Vs MDF construction, though some early 828s were plywood also; and the 828's reduced net volume [Vb] to accommodate the differing specs of later versions of the 416 and 515 due to the switch from relatively high output impedance, low power systems to vanishingly low output impedance, high power systems.
Since the cabs are tuned the same except for the earliest higher tuned dual slot vent 825s, both can be made to perform close enough to an identical frequency response when the appropriate drivers, etc. are matched to them.
GM
Thanks GM.
Marco, GM is one of the top dogs when it comes to Altec so maybe he can chime in here. Not sure but it may be that the 825 has the narrow baffle and the 828 has the wide? AFAIK there isn't a whole lot different about them, shape wise. They did change from 5/8 ply to 3/4 ply and then to MDF and the ports changed also.
EDIT: GM posted while I was typing.
Marco, GM is one of the top dogs when it comes to Altec so maybe he can chime in here. Not sure but it may be that the 825 has the narrow baffle and the 828 has the wide? AFAIK there isn't a whole lot different about them, shape wise. They did change from 5/8 ply to 3/4 ply and then to MDF and the ports changed also.
EDIT: GM posted while I was typing.
Dear friends. Thanks for the explanation, but my doubt regarding the baffle itself still remains. Which project should I consider? The one with "full width" or the other with only 18" speaker baffle width? Thanks!
You're welcome!
Again, it depends based on the driver/amp/XO combination and any other added series resistance that may be in the circuit. Also, the intended application [app], i.e. prosound, HIFI, HT, room acoustics, etc..
Personally, the single pair of cabs I built were 825 except using marine grade 3/4" and much better braced simply because the better braced 828 was 6-7 yrs away yet. Later, I blocked off the horn cavities [these act as crude band-stop filters BTW] and filled them with Oil Dry/Kitty Litter to stiffen, damp them and re-tuned the cab to a much lower Fb [~32 Hz]. These were for HIFI/HT and used 416A [16 ohm] originally and later, 416-8B. After selling them to my then next door neighbor, the 411-8A was introduced and we converted them to a two way: sealed off compression horn and the rest of the cab's net Vb as a sealed alignment for a 411.
All things considered though, the consensus AFAIK is build the 828 using at least a 3/4" thick void free plywood [Baltic Birch, Apple-ply or similar and with as many laminations as you can get/afford], stiffen/damp the horn cavities and all surfaces larger than [>] ~144"^2. For HIFI/HT apps, use a ~75"^2 port opening and adjust it as required for best overall performance in your room, etc..
If you have the space, adding 10"-15" wide [or wider] side 'wings' is a good plan as is adding a 15"-20" high top 'wing' to span the full width to create a false wall baffle large enough to lower the system F3 down to at least 70 Hz.
GM
Again, it depends based on the driver/amp/XO combination and any other added series resistance that may be in the circuit. Also, the intended application [app], i.e. prosound, HIFI, HT, room acoustics, etc..
Personally, the single pair of cabs I built were 825 except using marine grade 3/4" and much better braced simply because the better braced 828 was 6-7 yrs away yet. Later, I blocked off the horn cavities [these act as crude band-stop filters BTW] and filled them with Oil Dry/Kitty Litter to stiffen, damp them and re-tuned the cab to a much lower Fb [~32 Hz]. These were for HIFI/HT and used 416A [16 ohm] originally and later, 416-8B. After selling them to my then next door neighbor, the 411-8A was introduced and we converted them to a two way: sealed off compression horn and the rest of the cab's net Vb as a sealed alignment for a 411.
All things considered though, the consensus AFAIK is build the 828 using at least a 3/4" thick void free plywood [Baltic Birch, Apple-ply or similar and with as many laminations as you can get/afford], stiffen/damp the horn cavities and all surfaces larger than [>] ~144"^2. For HIFI/HT apps, use a ~75"^2 port opening and adjust it as required for best overall performance in your room, etc..
If you have the space, adding 10"-15" wide [or wider] side 'wings' is a good plan as is adding a 15"-20" high top 'wing' to span the full width to create a false wall baffle large enough to lower the system F3 down to at least 70 Hz.
GM
Nice Arne!
I regret not buying the model 19's when I worked at Altec - I just didn't have the extra $$$. I think they were around $500 a pair for the employees. A co-worker friend of mine did in fact buy a pair and I helped him set them up.
Any pics of your Mantaray setup Arne?
Nice Arne indeed. It is so long since I heard a pair it would be like a new experience. And yes I know they would (edit not) sound like the 825 boxes but probably still a real joy.
I think I wet myself 😱
Looks great Arne! I like the looks, kinda industrial looking, which I like.
JBL PA with Altec Lansing 421 Bass Dia-cone
I have just dragged an old PA out of a dead nightclub and found a variety of components inside large JBL cabinets. (I paid 50 bucks for both). There is the 15" Altec-Lansing driver, a 421 bass Dia-cone, series 1266. In the same cabinet is a JBL 2305 Horn known as a potato-masher, and a Celestion HF-50 Super tweeter. The other cabinet was the same except for a much lighter 15" Celestion driver. Was this a common configuration in the 1980's? Is this a good PA for a 5 piece band? Should I try and find a matching Altec Lansing to balance the cabinets? Were these good drivers and how does the JBL Horn and Celestion supertweeter work with the driver. Is this a reasonably good PA system?
Sincerely,
Rob
I have just dragged an old PA out of a dead nightclub and found a variety of components inside large JBL cabinets. (I paid 50 bucks for both). There is the 15" Altec-Lansing driver, a 421 bass Dia-cone, series 1266. In the same cabinet is a JBL 2305 Horn known as a potato-masher, and a Celestion HF-50 Super tweeter. The other cabinet was the same except for a much lighter 15" Celestion driver. Was this a common configuration in the 1980's? Is this a good PA for a 5 piece band? Should I try and find a matching Altec Lansing to balance the cabinets? Were these good drivers and how does the JBL Horn and Celestion supertweeter work with the driver. Is this a reasonably good PA system?
Sincerely,
Rob
Nice score. I love when that happens.
There's no such thing as a common configuration when you're dealing with home builds. 🙂
The driver complement seems decent. What are the Altec low ends?
The Diacone's are an Instrument speaker but probably work well as a mid-bass in your set up.
The 2305 horn are a nice compact unit and supertweeters may or may not be needed in a PA set-up.
Yes all drivers should match for best results.
They will be good for quiet to medium volume depending on the venue and the type of music. A single 15" will not fill a hall. It sounds like the were built for the nightclub for canned music. 🙂
The only question that really matters is - do they sound good to you?
There's no such thing as a common configuration when you're dealing with home builds. 🙂
The driver complement seems decent. What are the Altec low ends?
The Diacone's are an Instrument speaker but probably work well as a mid-bass in your set up.
The 2305 horn are a nice compact unit and supertweeters may or may not be needed in a PA set-up.
Yes all drivers should match for best results.
They will be good for quiet to medium volume depending on the venue and the type of music. A single 15" will not fill a hall. It sounds like the were built for the nightclub for canned music. 🙂
The only question that really matters is - do they sound good to you?