808-8b

[Eric Best]

Hi,

I found this forum a couple of days ago by accident, what a great find. It made me think of some leftover PA horns from long ago that were left at my house and never claimed. I looked at them last night and they are 808-8bs with a 511b horn. Are these suitable for handling all of the 500hz plus information for a home system or should some kind of tweeter be added? I was thinking of what I could come up based around this horn since they've been sitting in my basement for 15 years.

Thanks,

Eric

Yes I really do live in Lansing, MI

[speakerdave]

The 808 8b is the PA version of the 802 8G driver, often considered the most desirable of the Altec small format drivers. What these two have in common is the large magnet radial phase plug made of orange plastic, and so sometimes referred to as the tangerine. It is said to result in greater HF extension.

These two drivers are different in that the 808 8b originally comes with a diaphragm designed to take the pounding it gets in PA use. To make the 808 8b function like an 802 *g you would need to get the lighter aluminum diaphragm used in that driver. OE diaphragm equivalents can be obtained from Great Plains Audio.

Some people use the Altec horns and drivers without tweeters and some do not. You'd need to check that out for yourself, I think.

David

[Eric Best]

Thanks David,

Does the different diaphragm result in these not being a sensitive as the 802?

You gave me enough information so I can research more.

Thanks!

Eric

[sean19]

808-8b are great drivers pair them with some 416-8b and a model 19 crossover and you have some killer speakers they will be well worth your time building i use almost the same set up 802 and 416, mod 19 crossover and i love my system.

[speakerdave]

By the way--there is another Lansing board at Great Plains Audio:

http://www.hostboard.com/cgi-bin/ultimatebb.cgi?ubb=forum&f=3729

the truly and deeply weird Altec nuts hang out there.

David

[Gary L]

Once you switch to the 34647 or 23744 diaphragm and loose the loading caps your 808-8Bs will be 802-8Gs.

As mentioned above I think they sound great when crossed at the 12KHz of the 19 XO.

I'm not sure what difference you might find between the 19s 811B horn and the 511Bs you have. Probably might want a little bigger room I would guess.

Gary

[Eric Best]

I was thinking about using these to build a 9845 type monitor. Bi-amping it. I've build numerous active crossovers. After I changed the diaphragms would I still be able to cross it over like the 9845s at 500hz.

I'm building a recording studio in my basement. The control room is going to be over 2500 cu. ft. I think it might be fun to build these into the wall. They wouldn't be my primary mixing speakers. I have a good pair of reference monitors that I built and a pair of JBL 4206s for checking.

I think they would definitely fun to sit back on the couch and listen to mixes on.

[Russellc]

Once you switch to the 34647 or 23744 diaphragm and loose the loading caps your 808-8Bs will be 802-8Gs.

As mentioned above I think they sound great when crossed at the 12KHz of the 19 XO.

I'm not sure what difference you might find between the 19s 811B horn and the 511Bs you have. Probably might want a little bigger room I would guess.

Gary
Dont forget to add felts to the rear covers once you remove the loading caps.
You will also need shorter screws as when you go to install the new diaphragm you will find the existing screws are now too long, and bottom out before tightening against the diaphragm.

Get the whole kit and kabutal from great plaines, new diaphragm, new diaphragm mounting kit, as you will need to convert from the old screw on leads to the modern press on leads, new non magnetic shorter diaphragm mounting screws, as well as the felts to install in the rear covers.

All this stuff is cheap except for the diaphragms, and they're fairly reasonable as well. Good find on the 808 8B, as far as I am concerned the only thing you could have found better is a 802 8G, ( dont have to convert)
or some prefer the 902 8A, which I think I like better than the 902 8B. Its really close between them, I doubt anyone could blind pick them with any statistical signifigance.

Great find,



Russellc

[Russellc]

Once you switch to the 34647 or 23744 diaphragm and loose the loading caps your 808-8Bs will be 802-8Gs.

As mentioned above I think they sound great when crossed at the 12KHz of the 19 XO.

I'm not sure what difference you might find between the 19s 811B horn and the 511Bs you have. Probably might want a little bigger room I would guess.

Gary
I find the 511B sounds better to me than the 811B in anyroom. That said, I've heard plenty of nice setups with 811B, and own a pair myself but have always prefered the larger sound of the 511B.

Recently surprised myself with the cheap JBL wave guide on top of the A7s,
I can tell you that! Thanks Zilch!:applaud:

[Eric Best]

After the change would I still be able to crossover at 500Hz without damaging the driver?

[Gary L]

I don't have the electronic savy to say for sure but think you would want to be careful crossing 802-8Gs at 500 Khz.

I really like the Model 19 XOs crossing at 1200 Khz and matched with 416/802/811B combo.

I have never heard this combo with the 511B horn but find that horn in an A7 cabinet to be a bit much in most home sized rooms.

Just a personal opinion but I think my speakers sound best with some power going thru them and there seems to be a fine line between where they really sound great and then sound too loud in both of my set ups.

When I drag a pair of speakers out to the deck all bets are off and I find myself cranking them and moving around for the best possible sweet spot which is about 25 feet for me.

Gary

[Russellc]

After the change would I still be able to crossover at 500Hz without damaging the driver?
You will be just fine, for home hifi, your ears will blow out before the drivers. I had mine at 500 hz for years, not that much higher now at 800Hz. The only caveat I would add is if you are using first order filters-
otherwise there will be no problem. I have used 802 8D, 802 8G, 902 8B, and 902 8A, at all sorts of volume levels without a single problem....home hifi mind you, PA use may be a little harder on them for sure.

Russellc

[Russellc]

I don't have the electronic savy to say for sure but think you would want to be careful crossing 802-8Gs at 500 Khz.

I really like the Model 19 XOs crossing at 1200 Khz and matched with 416/802/811B combo.

I have never heard this combo with the 511B horn but find that horn in an A7 cabinet to be a bit much in most home sized rooms.

Just a personal opinion but I think my speakers sound best with some power going thru them and there seems to be a fine line between where they really sound great and then sound too loud in both of my set ups.

When I drag a pair of speakers out to the deck all bets are off and I find myself cranking them and moving around for the best possible sweet spot which is about 25 feet for me.

Gary
I agree with you on the power....I prefer a lot rather than a little, just my opinion. Many use SET and just a few watts, I like the sound of plenty of power myself. That said, I had the opportunity of hearing Jaymana's horns with 2a3 single ended and they sounded GREAT!

[Skywave-Rider]

I was thinking about using these to build a 9845 type monitor. Bi-amping it. I've build numerous active crossovers. After I changed the diaphragms would I still be able to cross it over like the 9845s at 500hz.

I'm building a recording studio in my basement. The control room is going to be over 2500 cu. ft. I think it might be fun to build these into the wall. They wouldn't be my primary mixing speakers. I have a good pair of reference monitors that I built and a pair of JBL 4206s for checking.

I think they would definitely fun to sit back on the couch and listen to mixes on.

Cool. A la Gold Star Studios.
Phil Spector, come on down!
You'd probably like this pic:
http://www.goldstarrecordingstudios.com/galler1.gif

[Eric Best]

hopefully in a year it will be that way. I've already started the framing on the main room so I still have time to make changes on the control room.32333

[sekess]

Hi Russell,


"Recently surprised myself with the cheap JBL wave guide on top of the A7s,
I can tell you that! Thanks Zilch!"

Which specific waveguides are these?

Thanks,
Steve

[Gary L]

Just some thoughts here but since you are able to build active XOs why not just build one that can select between the various frequencies discussed here and let your ears determine at what frequency the 808-8B rebuilt to 802-8G specs sound best.

Is there some underlying need to go with the 500Khz cross point?

Based on numerous threads in the past I seem to recall the 802-8G was best suited for the 1200 Khz and measured best with the model 19 XO.

Based on some measurements from Zilch's testing many have gone to the BMS 4550 driver but all of this was with the 811B horn and I think no lower then 800 Khz on that horn.

I would be interested to hear your opinions when the project is completed about what XO point sounds best with your 802s on the 511Bs. Keep in mind also the 19 XO incorporates a zobel filter that might make some difference in a home Hi Fi setting.

Gary

[Russellc]

Hi Russell,


"Recently surprised myself with the cheap JBL wave guide on top of the A7s,
I can tell you that! Thanks Zilch!"

Which specific waveguides are these?

Thanks,
Steve
It is the little cheap 9.90 wave guide zilch has been using in the econowave guide thread over at AK He has also used them in several threads in this forum as well. Part #338800-001 Outstanding!

Russellc

[Eric Best]

Just some thoughts here but since you are able to build active XOs why not just build one that can select between the various frequencies discussed here and let your ears determine at what frequency the 808-8B rebuilt to 802-8G specs sound best.

Is there some underlying need to go with the 500Khz cross point?



Good idea, jumpers can be used to cheaply to make the adjustments, but the reason to go with the 500Hz crossover is to come up with something similar to a 9845 which is crossed over at 500Hz.

Does anyone have any inside pictures of the 9845 or know if it similar to the 9844 with different dimensions. I'm trying to figure out bracing and port locations (or if it even had ports) are they round or rectangular.

Also, after reading Skywave's 9844 thread for about the 10th time I made the connection that the 416s should be 16ohms, is that correct?

[Earl K]

http://audioheritage.csdco.com/vbulletin/attachment.php?attachmentid=16418&stc=1&d=1151332183
Gary,


Keep in mind also the 19 XO incorporates a zobel filter that might make some difference in a home Hi Fi setting.

- FWIW, unless the above schematic was transcribed wrong by Jim E., the M19 ( 1201-8a ) Network doesn't use a Zobel network ( within the woofer section ) .

- The 1209-8a does use a Zobel network ( in the woofer section ) . It ( most likely ) would have been included to help the network function properly with a variety of different Altec woofer models .

:)

[Skywave-Rider]

hopefully in a year it will be that way. I've already started the framing on the main room so I still have time to make changes on the control room.
Looks good. Are those LSRs actually to be ur nearfields? Wonder how u like them.

Can you soffit mount the mains tilted down, closer to the wall/ceiling border, with the horn on the bottom? I intend to use my 9844s for some tracking/mixing eventually and they were designed with that orientation in mind, it seems. But I'll have to keep mine on wheels and low stands. Your setup should be great.

I think clients will love the look -- will they love the sound? -- Good question. If it's "big" probably yes. :)

[Gary L]

Thanks Earl,

"- FWIW, unless the above schematic was transcribed wrong by Jim E., the M19 ( 1201-8a ) Network doesn't use a Zobel network ( within the woofer section ) .

- The 1209-8a does use a Zobel network ( in the woofer section ) . It ( most likely ) would have been included to help the network function properly with a variety of different Altec woofer models . "

I am just repeating what I have read here and at the Altec site many, many times and wouldn't know a Zobel if I tripped over one, nor would I know where it is in the circuit!

I guess it's true about not believing anything we read from those who claim to know!

Regarding the use of 416s and 8 or 16 ohms, I guess I will make yet another uneducated assumption. 2- 16 ohm speakers in a circuit equals 8 ohms in the end. Again, just something I have read here and always relied upon. Likewise if you use 2- 8 ohm woofers you would end up somewhere around 4 ohms.

I have no idea if these number are even close but I sure have seen plenty of 16 ohm 414s doubled up and used in 8 ohm XOs.

Gary

[Zilch]

I have no idea if these number are even close but I sure have seen plenty of 16 ohm 414s doubled up and used in 8 ohm XOs.From Skywave's work, it looks like some of them may be getting UNdoubled, now.... ;)


The 1209-8a does use a Zobel network ( in the woofer section ) . It ( most likely ) would have been included to help the network function properly with a variety of different Altec woofer models .Do we know the component values for the supplementary Zobel, Earl?

[Earl K]

Do we know the component values for the supplementary Zobel, Earl?

- 7.5 ohms & 18 uF

:)

[Zilch]

- 7.5 ohms & 18 uF

:thmbsup:

[Eric Best]

Skywave,

I just got those speakers out of the google sketchup library. Right now I mix on a pair of Solists, which are a design from Madisound that I built that I do most of my mixing on. I like them a lot. http://www.madisound.com/catalog/product_info.php?cPath=35_39&products_id=407

I have a pair of JBL 4206s and an Aurotone clones that I made.

I have read a lot of things saying that you shouldn't flush mount on an angle because you will lose some of the baffle effect. I think I will mount them the other way though. I have read a lot more about the speakers since I made that drawing.

What kind of bracing do your 9844s have inside?

[Skywave-Rider]

Those Solists look good, never heard them. Are u using them in a vertical configuration?

The Altec lit. for 9844-8B claims the cabinet is "heavily braced." And the stepped baffle is pretty substantial. But the rest of the box has basic corner braces. I don't know if it can be improved upon. I have seen posts around where guys put all kinds of cross bracing in there. If I can find a good pic of the inside I'll post it for you. There may be something in the 9844 thread.

As far as the mains mounting, I don't know. I've used control rooms designed both ways. (Never built and installed though.) I tend to think whatever can get the horn to your ears with minimal reflections off of the meter bridge, etc,. is the way to go. A big factor is ceiling reflections too. Angling them down to the mix position eliminates that problem.

If you're using the 511 horn, I think the vertical dispersion is like 40 degrees, so ceiling bounce may not be an issue if you are close enough.

What is your console/workstation?

Will you use diffusion in the back? Bass traps? LEDE design?

Cool project.

[DavidF]

Cool. A la Gold Star Studios.
Phil Spector, come on down!
You'd probably like this pic:
http://www.goldstarrecordingstudios.com/galler1.gif

I recognize Hal Blaine there in middle and probably Tommy Tedesco on guitar in the back. Carole ?? on one bass. Yikes, looks like a all-hands photo of the Wrecking Crew.

[Eric Best]

This is my general plan. At the back of the control room is 3ft of trap similar to a non environment room, the walls should be splayed to deflect all reflections past the mix position, the ceiling will be 1.5' of trapping.
32361

[Skywave-Rider]

Eric, wondering if your control room will be its own box, that is capped and isolated from the structure? (I.e., are you cutting the slab?)

Great plan. I would add an iso on the other side or put some glass into the door and make that one.

I'm very jealous....LOL

Cool!

[Eric Best]

Hey Skywave, I do have some limitations, it is my basement and I still need it for basement things unfortunately. I'm going to isolate it as much as possible without major structural changes. I'm doing a pretty involved HVAC system to isolate the rooms. It isn't going to be perfect, but it should be pretty good.

[Eric Best]

I've been reading about this driver, would I be as well off buying a pair of these and leaving the 808-8b as a PA horn. It would be cheaper to buy a pair of these then rediaphragm the Altecs.

[Skywave-Rider]

Your studio design looks great to me. I bet you could do serious stuff in there. Give me a discount on time if my band comes to your area.
:D:thmbsup:

I have 4550s on my home workstation. If you want to read my comparo between the 4552NDs (should be similar to 4550s) and 902s on my 9844s which have the 811B horn read this:
http://audioheritage.org/vbulletin/showpost.php?p=208085&postcount=189

The "Zilch approved" BMS will give you flat response up to 20k, on those horns. I forgot what your crossover will be. With the stock crossover I get flat -- no additional compensation.

BMS will better for working if you use the mains for EQ settings and balancing, as opposed to just "checking" while on the couch. Or giving your client the vintage vibe -- I like that idea, too. My opinion, of course.

For my apt. workstation, I have the BMS 4550s biamped on top of the old Sentry 100As. They are better than my Genelec 1030s. Seriously.




I've been reading about this driver, would I be as well off buying a pair of these and leaving the 808-8b as a PA horn. It would be cheaper to buy a pair of these then rediaphragm the Altecs.