Budget woofer system with Horn

[gwho]

Hello everyone, I just joined this forum to get a better understanding of Horn speakers. I've mostly listened to full-range electrostatic speakers for the last decade or so. I am intrigued by high efficiency speaker systems that support a wide dynamic range. This is the one failing of electrostat speakers and I'd like to see how a horn system sounds with a low wattage tube amp. I was going to buy a Klipsch CF-4 speakers but on a whim I purchased a pair of Altec horns off of Craigslist. I'm not much of a speaker builder but was wondering if there is a cost effective woofer system (that has been tried and documented) with a reasonable foot print that integrates well with an altec horn. I've looked on ebay and a built box such as an Altec 8256 is quite expensive (shipping is a killer) plus the drivers are 30 years old. As an alternative, there are a pair of Santana speakers with the biflex woofers that are local that can be had for a reasonable price. I realize the biflex system is a full range but this could support integration to the horn if the low frequency is a adequate. The only thing I don't know about is the low end on the Santana's. Also, would there be a significant efficiency mismatch. If you think the biflex would work I could always add a subwoofer for the low end. Also, I am not opposed to finding similar JBL or other bass components that might work. I can see the price of this escalating to the point where I would be better off just buying something like an Altec 14, 15, 19 in which case I'd sell the horns and buy the real thing. I'd like to thank everyone in advance for any input they might provide.

Regards,
gwho

[more10]

Which Altec horns did you buy? Driver?

Even if you buy a woofer box, you will have to deal with the crossover. Construting passive crossovers for horns is difficult. Active crossovers are simpler, and you can combine solid state amps for bass with tube amps for the horns.

If you just want to listen to your system, buy a complete working system. If you want to do this as a hobby, keep your horns and get the other stuff you need. This is great fun, you will not regret it if you keep the horns.

[gwho]

Thanks for the response. I was wondering if I worded my question wrong. I realize that many DIY designs can supercede vintage speakers that were designed before the pc was invented. My assumption is that this would be true for the woofer section of a horn system yet by having the horns keep that vintage sound. The horns I picked up are listed as Altec 288-8k on the back of the driver. The horn part of it is quite large and I don't know if I would want to use it unless someone tells me that it is good. My wife looked at these things and was aghast. I really would like something smaller. The horn is a MR94a and measures almost 3 x 2.5 feet. There is a metal adapter from the driver to mate to the horn. They look to be in good shape and were pulled from a church. I have a couple of Rane analog crossovers and plenty of amplifiers. I would likely not use a passive crossover as part of the project. Would I be better off waiting to find a vintage Altec woofer box or have there been some good woofer box designs that would mate with the horns I picked up that have tested. I don't mind building a box that's the fun of these projects especially if it improves what was the state of the art. I've attached a picture of the horns. 61238

[gwho]

As I mentioned previously, would you think that the Santana could be crossed to the horns and give a good sound. Would the biflex driver have sufficient punch and low frequency extension to match the horn.

Thanks
gwho

[Mr. Widget]

I would have to say that I agree with everything that more10 said.

Building DIY speakers is extremely gratifying, however it is not a trivial pursuit and to actually end up with something better than what is commercially available takes a lot of experimenting and experience.

I guess what I'm saying is don't hesitate to explore your options however don't expect success right away.


As for what you should do with those horns, I would investigate our information in the Altec area and I would go to Todd White's website and see what people there can offer. Those horns are not terribly vintage. They're actually fairly late Altec production. Beyond that I know nothing about those horns so I can't offer any practical advice.


Widget

[gwho]

Thanks for the advise. Could you suggest one or more altec boxes with drivers (or other brand) that I should keep my eyes open for that have great dynamics and punch. I will also take a look at the cite to learn more.

gwho

[more10]

These are Mantaray horns. I have no experience with these but they should go low.
Altec 288-8k (http://www.greatplainsaudio.com/vintage_altec/288-K%20Series_hfdriver_spec_sheet.pdf), low frequency limit is 500 Hz. Usable from 800?
Technical Notes Vol. 1, No. 4 Constant Directivity Horns (http://www.diyaudio.rs/JBL/JBL%20Technical%20Note%20-%20Vol.1,%20No.4.pdf), JBL says cutoff at 800. I don't trust this figure.
Installation and service instructions (http://www.greatplainsaudio.com/vintage_altec/HF%20Driver%20Repair%20Instruction.pdf)

I believe you can find smaller horns with a practical lower frequency of 800 Hz.

Finding a 15 inch driver going up to 800 Hz is no problem at all. Deciding which one you want is more difficult. I believe Altec 15 inch drivers cost more on ebay than JBL. Building a vented enclosure going to 800 is difficult since the port will radiate midrange frequencies unless cleverly damped inside the box. JBL 2226 should be easy to source and sounding good as well. You will get plenty of cabinet designs for it

[Lee in Montreal]

Mantaray and Altec 817 cabs

http://upload.review33.com/images/200909/200909072130077584.jpg

Plans
http://www.audioheritage.org/vbulletin/showthread.php?33103-Altec-817-plans-that-are-correct

[more10]

Of course. 817 spec sheet (http://www.greatplainsaudio.com/vintage_altec/817A_basshorn_spec_sheet.pdf). Will not make the wife any happier though.

Or 816 single driver horns.

Found this thread: Should Altec 288 compression drivers sound like this? (ringing) (http://www.audioheritage.org/vbulletin/showthread.php?20122-Should-Altec-288-compression-drivers-sound-like-this-(ringing))

[more10]

Altec Lansing GPA 515 515-8G NEW (http://www.ebay.com/itm/Altec-Lansing-GPA-515-515-8G-NEW-/230602959047?pt=Vintage_Electronics_R2&hash=item35b101e8c7). 300$ is a very good price.

[Lee in Montreal]

Will not make the wife any happier though.

When the man has balls big enough to bring a set of Mantaray horns home, we already know that wifey has no say about what he does with them. With the horns, of course. Not the ballz. ;-) But hey, if (relative) compactness is needed, then may I suggest twin JBL 2225/2226 in an 11cft bass reflex enclosure. Roughly 36" wide x 24" deep x 24" high.

[gwho]

First, I have the balls to bring the horns home but not in the house. The first thing the wife said was "don't you even try to bring those in the house". The kids thought they were pretty cool though (they are teens). I think some of the responses were quite helpful in giving me some direction. More10 thank you for the technical notes on the driver I have. I will read up on it. It appears that I have the MR94A, 24654 Throat, and 288 driver. From the diagram it appears that an 805B or a 1005B horn will work with my driver and should result in a much smaller form factor. Lee in Montreal thanks for the pics. That system looks pretty cool. It also looks pretty big. Would a single GPA 515 be sufficient match for the 288-8k? Is there an established box design for it that I could copy? Also, did the GPA 515 come in a box that I might find someone selling locally? Similar question to the twin JBL 2225/2226. Did it come in a JBL box that might be had locally used at a good price? It seems that the most common Altec box with drivers being sold on ebay were the 8256 with two 15" speakers.

Much appreciated
gwho

[more10]

Try to swap the horns for multicells:

http://upload.wikimedia.org/wikipedia/en/thumb/d/d0/Altec1978multicell.jpg/570px-Altec1978multicell.jpg

The big ones look really nice

[gwho]

More10 the multicell horns do look nice! I did some searching and it appears that what I have lends itself most to building an Altec A6. I tried to find some discussions on the A6 but there is not much out there. It appears that the A6 is not well thought of compared to other voice of the theater speakers. The A6 includes the 8256 with 3156 drivers. If I found a pair of these are there any significant issues with the 3156 that I should look for? Do the 3156 hold up well? I assume they will probably be about 20 years old. I found this picture and I believe it has the horn I have on it. Does it make a significant difference which way you mount the horn? As shown the slot is vertical.61308

As usual thanks for the input
gwho

[Lee in Montreal]

Gwho - Yup. Slot must remain vertical for optimal dispersion.

http://i443.photobucket.com/albums/qq158/analog_addict/CIMG6768.jpg

If space is a limitation, you can make a cabinet with one single 15" driver. I have the JBL "equivalent" of your Mantaray and use it for home duty with a single JBL 2226 in a bass reflex enclosure. The 2226 works fine down to 40Hz. I have an 18" 2245 for infrabass. Very often I don't even power the 18" driver. For best integration I also have a digital crossover and multiple amps. I ended up with a very simple two-way system.

To reduce the visual impact, you can make your cabinet narrow, yet deep. You need depth anyway as your Mataray will most likely require 36" depth. Build a 36" deep x 18" wide x 24" tall cabinet. Looking from the front, it will look "tiny" at 18" wide x 24" tall. The combined height of the bass cabinet and Mantaray will be no more than 48". What's the Mantaray width?

http://img.photobucket.com/albums/v668/Lee_Vuong/JBL parts factory/DSCN2391_zpsdf7728b2.jpg

http://img.photobucket.com/albums/v668/Lee_Vuong/JBL parts factory/DSCN2394_zps56463075.jpg

http://img.photobucket.com/albums/v668/Lee_Vuong/JBL parts factory/DSCN2463_zpsb8c05d3b.jpg

[gwho]

Lee wow you do beautiful work. Your speakers are a work of art! I'm afraid I do not have that level of skill. Space will not be a limitation (at least not now). I will likely just pick up a pair of 8256 with drivers to get up and running as quick as possible. If I can get them into the house I will likely have to make them look less obnoxious. I wonder if the 8256 can be improved or modified to extend low frequency response. Thanks for the pics. I was wondering how you mount the horn to the box. Is the placement of the horn to the box have any phase alignment or do you handle this digitally.

gwho

[more10]

Hoktuna at Hififorum.nu built Altec 816 cabinets to use with his homemade multicells (http://www.hififorum.nu/forum/topic.asp?TOPIC_ID=74565&whichpage=2):

http://i194.photobucket.com/albums/z134/hoktuna/DSC_0089.jpg

[Lee in Montreal]

The Altec 8256 is a "smallish" 6cft cabinet. Would be great for one single driver. But for two, it means each driver only has 3cft. That's not much. That will restrict the lower range and will make bass boomy. But 6cft was probably great for portable sound reinforcement. But if you have access to such cabinet, you could fit one single 15" driver (JBL 225, 2226, 2235), block the unused mounting hole, and fine tune the ports by perhaps blocking one of them to get a lower reach. But you know, building a simple 36"x 24" x 24" cabinets for two drivers is failry easy. That's one sheet of 8'x4' per cabinet. BTW empty A7 cabinets very oten end up on kijiji for dirt cheap. That would be a good match with the Mantaray. They often go for $200 a pair.

[gwho]

More10 and Lee,

I live in a major metropolitan area (Phoenix) so I can be patient to wait for boxes if they come up often. There aren't any at this moment. I definitely like the look of the multicell horns but they are priced way to high (~$700 for the 1005 / 805 horns on epay. Are there other more prevalent horns that will work? There are also A7 cabinets for sale but they want 325 a piece which is quite a bit different than 200 a pair. I could not find any 816 cabinets for sale. Thanks for the tip on the 8256. That could definitely work. Is there a reason why a single 3156 would not work in the cabinet or is the 2226 much better (or go lower). I also would consider building a box but I thought it was mentioned in this thread that it could be difficult to build and/or problematic to achieve better results. Do you know of a box plan that is known to work well with a specific driver. If so, please let me know.

Best Regards,
gwho

[gwho]

I will look into the 816 cabinets. They look nice and appear to be a nice size.

gwho

[more10]

816A spec sheet (http://www.greatplainsaudio.com/vintage_altec/816A_basshorn_spec_sheet.pdf)

[Lee in Montreal]

@gwho

You will notice from the posted picture that the 816 requires two subs (located behind, near the wall) for bass. That's because those are upped/mid bass and midrange cabinets. If it is what you need and have subs for the 20-80Hz range, then you will be happy with them.

Lee

[more10]

This is how Hoktunas system (http://www.hififorum.nu/forum/topic.asp?TOPIC_ID=82919&whichpage=3) looked like a year ago or so:

http://i194.photobucket.com/albums/z134/hoktuna/DSC_0214.jpg

The subs are the white boxes with the small horns on top. These are Tapped Horns of Petter Persson design. The round horns are LeCleach from Auto-Tech. The big ones are 200 Hz horns and the small ones are 1000 Hz. This is the best sounding sytem I have ever heard. The LeCleach horns sound better than multicells, but are not so wife friendly. Hoktuna has his system on top of the garage, and his wife rarely goes there.

The Altec 816 will give you good horn sound down to 200 and that makes a big difference.

[Lee in Montreal]

Hoktuna has his system on top of the garage, and his wife rarely goes there.

;-)



The Altec 816 will give you good horn sound down to 200 and that makes a big difference.

Agreed

[gwho]

Let's assume that I could find a set of 816 enclosures inexpensively. What driver would be the best match for the driver that I have? Would I want to use the 515b or the JBL 2225/6 that was previously suggested. Would my horn even be a match for this enclosure. Sorry for all the questions. I have a nice subwoofer that could be used with it. It is a dipole subwoofer comprising 4-15" drivers with a separate EQ that extends to 20Hz.

gwho

[gwho]

I'm also talking to someone out of state on a pair of 8256 with 3156 drivers. I might have a go at these if I can get them at the right price. Would removing one of the drivers (plugging up the opening) and closing up the port to double the box size work with the 3156. I really appreciate the help with these different suggestions.

gwho

[Lee in Montreal]

2225 vs 2226

The 2226 will play hard. It will be generous in mid bass and mediums (those must be tamed from 100Hz and up). Considering the 816 will acoustically put the emphasis on the 150Hz and over, I think the 2226 might not be ideal for hifi. The 2225 is a bit more limted in the amount of power it can accept, but I feel it is a bit more linear. Its bass goes a bit deeper, and it doesn't have that midrange hump. But the 2226 is a great contender nonetheless. I am curious to hear what others think on this subject.

Lee

[gwho]

Lee,

Can I ask your normal sitting distance from the speakers. How big are your horns? I read MR94's are constant directivity and mine measure about 3' by 2.5'. Are your horns constant directivity also. How do they sound?

Regards,
gwho

[Lee in Montreal]

My horns are slightly smaler and they are constant directivity. Dimensions are 30-1/2" x 30-1/2".

I like the sound. The horn sounds big. Great for jazz as well as electronic. I understand that some people don't like the 2360 though. I am happy with them.

Be aware that as any CD horn, it will require equalization if you want to use them up to the higher octave. I use my horns in a two-way system.

Lee

[gwho]

Here are some Altec cabinets. Do you think they are 816. http://www.ebay.com/itm/Vintage-Altec-Lansing-Bass-Cabinets-for-15-Speakers-Set-of-4-/131098186844?pt=Vintage_Electronics_R2&hash=item1e860f945c


gwho

[Lee in Montreal]

They do have the shape of an 816. At that price, get them and experiment.

[gwho]

The Altec cabinets are located in California which is a 12 hour round trip to pick up. I'd like to get something local (and low cost) to get started. I have a line on a local pair of JBL 4648a bass bins that are within my budget. Are there any mods that can be done to these. They look similar to the Altec 8256. I realize they are not like the A7 or 816 cabinet. As usual thanks for any input.

gwho

[more10]

http://www.jblpro.com/BackOffice/ProductAttachments/4648a.pdf


Recommended crossover High-pass: 40 Hz, 12-dB/octave
frequencies: Low-pass: 500 or 800 Hz, 12- or 18-dB/octave


Two 2226 in each cabinet. Should work with your horns. Electronic crossover at 800/24dB should do the trick.

[gwho]

Thanks more10. Is there a multicell horn that might go with this set up that you can suggest that could be had at a reasonable price and fits the 288 driver. The 1005 and 805 horns are out of my reach if ebay is any indication. I guess I could go to a smaller mantaray.

Regards
gwho

[more10]

Auto-tech made tractrix horn (http://www.diysoundgroup.com/horns/tractrix350.html). They have other horns as well, Only this and the K-horn has 1,4" versions.

[gwho]

Thanks more10 I will look into it. Does this sound better than the multi-cell or CD horns? Would this sound different than my MR94a?

gwho

[more10]

The tractrix horn is more hifi than the multicells or the mantarays. I belieive it will sound better if properly filtered. It will have a much smaller sweetspot than multicells or mantarays. And requires different filtering.

The mantaray will have a much wider sweetspot. Multicells somewhere between the mantarays and the tractrix.

[gwho]

I can't believe it. I was ready to go over and pick up the 4648a's and the guy sold them out from under me. He had 7 pairs and I just wanted one. He sold them all to one person. I'm trying to get a pair of the cabinets because the person who purchased them bought them for the speakers. I guess it is back to the drawing board.

gwho

[gwho]

Quick question. What would be a fair price for an original Altec 8256 (dual 3156) with the N1285-8b crossover.

Regards,
gwho

[more10]

Altec 8256 cab w/3156 15"s (http://www.audioheritage.org/vbulletin/showthread.php?15046-Altec-8256-cab-w-3156-15-quot-s). The box i high tuned (65 Hz).

3156 specification (http://www.greatplainsaudio.com/downloads/3156.pdf). They are quite cheap at ebay. $600 maybe.

[gwho]

more10 thanks for the guestimate (I assume you mean per bin).

How does the dynamics/impact of the 8256 compare to the 4648a's. Do they sound different? From what you said the 8256 rolls off at a higher frequency than the 4648a. My intention was to use a sub with either bin. Also, earlier in the thread it was mentioned that I should use a single driver in the cabinet to increase the low end. Would this work with the 3156 driver.

Thanks
gwho

[wpod]

Nothing here

[more10]

No. 600$ in total. A driver is 100$. These boxes are painted, no veneer. They are probably made from cheap plywood and if abused the plywood could have delaminated. I value the boxes at 100$ each.

If the sub reaches 60 Hz there is no point in removing one driver from the 8256.

[gwho]

more10 that helps a lot. Thanks gwho

[gwho]

I believe I've worked out a deal to purchase a pair of 8256 boxes with 3156 drivers. I have to drive out of state to pick them up but will make a weekend out of it. The 816 boxes are located in the same area. Is there any value in using a 3156 in the 816 box (they measure 30x26x22) over the 8256 box because I could pick them up at the same time. Any thoughts?

As usual thanks for the help
gwho

[Lee in Montreal]

If I were you, I would stick to a pair of 816. You will have horns working down to 180Hz. Then mid bass down to 60-80Hz from the 816. Which you can complement with your subs.

Also, the woofer in the 816 is about 2" deep and can easily be physically aligned with the compressor in your Mantarays, with the Mantarays' face portruding by probably only 9"-12"

It makes way more sense to go with those 816. I won't add anymore to the discussion.

Lee

[gwho]

Lee in Montreal

Could you please elaborate a little further. Are there significant benefits sonically in using the horn enclosure vs the vented system. Would the 816 be better match in efficiency? Or is it just that you want to have a horn with a horn.

I appreciate any input as I am new to all of this. I am in no rush but am trying to put together something that will work. I'd like a good starting point and then improve on that. The only reason I looked for the 8256 cabinets is that it is the way Altec built the A6 and A10 in the brochure from the archives.

If I bought the bought the 816 cabinets with the 8256's (allowing me the option to try both) would the 3156 woofers work in the 816? Or, would the 816 be much better with the JBL 2226 as this is a known quantity.

Regards,
gwho

[Lee in Montreal]

All your answers are already in this thread. I also suggest that you experiment. It's called trial and error. Have fun.

Lee

[gwho]

Thanks I am having a blast.

[more10]

I believe I've worked out a deal to purchase a pair of 8256 boxes with 3156 drivers. I have to drive out of state to pick them up but will make a weekend out of it. The 816 boxes are located in the same area. Is there any value in using a 3156 in the 816 box (they measure 30x26x22) over the 8256 box because I could pick them up at the same time. Any thoughts?

I would go that far for the 816, not the 8256.


816A spec sheet (http://www.greatplainsaudio.com/vintage_altec/816A_basshorn_spec_sheet.pdf)

Spec sheet says 416-8A or 421A or 515B. Use your money on 4 of these drivers instead of the 8256. And get all four 816 just to be able to compare how much extra punch you get from stacked horns.

[more10]

Also, the woofer in the 816 is about 2" deep and can easily be physically aligned with the compressor in your Mantarays, with the Mantarays' face portruding by probably only 9"-12"

This is a very good point.

[more10]

Horns have a more dynamic sound. Prefferably you want horns all the way down. But bass horns are big! So you shift from horns to ported designs somewhere in midrange. The 816 will sound better in the region above 200 Hz.

[gwho]

This gives me a much better understanding of the horn vs vented design. Thank you for the help. The deal did not work out for the 816 boxes. I did pick up a pair of the 8256's. I am determined to find a horn locally to compare against the 8256. I am also looking at what I believe is a folded horn. It is an old Peavey FH-1. I might get this to try also.

Regards,
gwho

[Eaulive]

Nice setup Lee... do you miss your 4520s?
I know the wife doesn't :D
How are the Yammies?


Gwho - Yup. Slot must remain vertical for optimal dispersion.

http://i443.photobucket.com/albums/qq158/analog_addict/CIMG6768.jpg

If space is a limitation, you can make a cabinet with one single 15" driver. I have the JBL "equivalent" of your Mantaray and use it for home duty with a single JBL 2226 in a bass reflex enclosure. The 2226 works fine down to 40Hz. I have an 18" 2245 for infrabass. Very often I don't even power the 18" driver. For best integration I also have a digital crossover and multiple amps. I ended up with a very simple two-way system.

To reduce the visual impact, you can make your cabinet narrow, yet deep. You need depth anyway as your Mataray will most likely require 36" depth. Build a 36" deep x 18" wide x 24" tall cabinet. Looking from the front, it will look "tiny" at 18" wide x 24" tall. The combined height of the bass cabinet and Mantaray will be no more than 48". What's the Mantaray width?

http://img.photobucket.com/albums/v668/Lee_Vuong/JBL parts factory/DSCN2391_zpsdf7728b2.jpg

http://img.photobucket.com/albums/v668/Lee_Vuong/JBL parts factory/DSCN2394_zps56463075.jpg

http://img.photobucket.com/albums/v668/Lee_Vuong/JBL parts factory/DSCN2463_zpsb8c05d3b.jpg

[Lee in Montreal]

Nice setup Lee... do you miss your 4520s?
I know the wife doesn't :D
How are the Yammies?I miss the 4520, and bass horns in general. Bass reflex is fine, but it lacks the dynamic of a bass horn. And my basement is too small to fit a pair of Berthas and Levans. ;-) and the Yamies keep on pumping. I used the PC2002 bridged into 700w to feed the 2245 sub. I will replace the 2226 by a pair of 2245 or maybe recone them as 2240. Baskets are 2245 and ready to accept a cone kit. Fresh and clean.

[gwho]

This is what I picked up. I hooked up the speakers for a basic test using an old analog electronic crossover (Rane AC22). I have to admit that the Altec sounds significantly different than what I am used to (electrostats). To my ears the horn sound very edgy (almost harsh). I was playing them through solid state equipment I have in the garage (acoustics are not first rate). Of note, the high frequencies (especially cymbals) did not sound accurate (smeared and bright from about 10 feet). Vocals sounded fantastic. How do I tell if there are issues with the diaphragm? One of them is dead as it measures an open circuit. I will likely replace them (any specific one I should pick up?). Is it worthwhile recapping the 1285 crossover or should I stick with electronic crossovers. I also picked up a pair of Peavey FH-1 that were local to try them out since I was unable to get the 816. This is a folded mid-bass horn of which there are a lot of write ups on the web (pros/cons) but I thought it would be worthwhile to test them to see what they sound like (they are supposed to be similar to a Klipsch Belle). They are more efficient than the 8256.

Are there any upgrades that can be performed on the 8256 to improve them?

Regards,
gwho

[hjames]

Everything I ever heard about ALTECS was they were efficient and pretty unforgiving about noisy SS gear.
I'm not sure feeding your HF audio through the RANE crossover is helpful - I think a passive xover is a better approach.


This is what I picked up. I hooked up the speakers for a basic test using an old analog electronic crossover (Rane AC22). I have to admit that the Altec sounds significantly different than what I am used to (electrostats). To my ears the horn sound very edgy (almost harsh). I was playing them through solid state equipment I have in the garage (acoustics are not first rate). Of note, the high frequencies (especially cymbals) did not sound accurate (smeared and bright from about 10 feet). Vocals sounded fantastic. How do I tell if there are issues with the diaphragm? One of them is dead as it measures an open circuit. I will likely replace them (any specific one I should pick up?). Is it worthwhile recapping the 1285 crossover or should I stick with electronic crossovers. I also picked up a pair of Peavey FH-1 that were local to try them out since I was unable to get the 816. This is a folded mid-bass horn of which there are a lot of write ups on the web (pros/cons) but I thought it would be worthwhile to test them to see what they sound like (they are supposed to be similar to a Klipsch Belle). They are more efficient than the 8256.

Are there any upgrades that can be performed on the 8256 to improve them?

Regards,
gwho

[more10]

One of them is dead as it measures an open circuit. I will likely replace them (any specific one I should pick up?).

Replacement diaphragms from GPA (Great Plains Audio) on ebay. You will have to read the manual in order to pick the right diaphragm :-)

[more10]

The Rane filter is not world class. Get a DBX. You will also need to build passive eq in order to harness the horns. Or get a digital filter with PEQs. Or take your chanses with the passive crossover.

[gwho]

I realize that what I put together is a cluge. I was anxious to hear what they sound like since I have almost no listening experience with horn speakers. I know a lot of what I heard could be the room or the electronics but some of it has to be the speakers. As I said they did sound kind of harsh to me. I'm sure the tube amp would tame some of that. Long-term I was going to drive the speakers with a Rogue Magnum tube amplifier once I get everything together. I will likely recap the passive crossover if I go this route. I also have a Behringer DCX2496 and DEQ2496 that I can use as a crossover and room eq should I want to biamp.

I could not find anything on the 8256 vented box nor how to improve it. I did find one general article stating that placing filler in the box would help.

As usual thank you for the input.

Regards,
gwho

[more10]

The Behringers are marginally better than the Ranes. But you can use them to find a filter curve for the horns. The horns are quite nonliear.

The vented boxes will output some midrange through the ports. Limiting this midrange (throuch damping material) will improve sound. Or you could rebuild the boxes with a 8-12 inch midrange in a dogbox replacing one 15 incher, creating a 3-way system.

[gwho]

fyi, I did not see any diaphragms on ebay from great plains for the 288-8k. I only saw ones from hong kong.

gwho

[more10]

Do you have measuring equipment? If not, a cheap solution is UMIK-1 (http://www.minidsp.com/products/acoustic-measurement/umik-1) from miniDSP. You will also need a PC and measuring software. REW (http://www.hometheatershack.com/roomeq/), Holmimpulse (http://www.holmacoustics.com/holmimpulse.php) or Arta (http://www.artalabs.hr/), or all of them. These are all free/shareware, so they are not very intuitive.

You really need to start measuring now.

[more10]

fyi, I did not see any diaphragms on ebay from great plains for the 288-8k. I only saw ones from hong kong.

gwho

http://www.ebay.com/itm/Altec-Lansing-GPA-288-291-299-Replacement-HF-Diaphragms-/231126956935?pt=Vintage_Electronics_R2&hash=item35d03d7b87

Ok, I will read the manual for you and do the googling :-)

[gwho]

Thanks for the help more10. Will I have to EQ the horn since it is non-linear? Would the passive crossover that I have (1285-8b) have compensation for the horn?

regards,
gwho

[gwho]

The only thing I have is a radio shack meter. I have been using a receiver that has built in eq for low frequency using a microphone to the processor. I probably should try to get some of the measurement software.

gwho

[more10]

Thanks for the help more10. Will I have to EQ the horn since it is non-linear? Would the passive crossover that I have (1285-8b) have compensation for the horn?

regards,
gwho

You are welcome.

You will need to EQ the the horns since the horn/driver combination is non-linear. The horn is a kind of CD (Constant Directivity) horn. The frequency curve is falling (with frequency). CD-horn at wikipedia (http://en.wikipedia.org/wiki/Horn_loudspeaker#CD_horn_characteristics).

The spec for the crossover (http://www.greatplainsaudio.com/vintage_altec/N1285-8B_xo_spec_sheet.pdf) doesn't mention EQ, but it does mention your horn.

[gwho]

Thanks more10. This is all information that I do not know. I will try to read up on it. At least right now I would like to keep it as a two-way with a sub. I don't want to over complicate it. I will set the crossover at 500hz and add eq. to compensate for the non-linearity of the horn. I will also fill the box with some fiber fill, recap the crossover, and pick up a diaphragm for the dead driver. If it sounds significantly better than the horn that works I will also buy a diaphragm for that speaker.

gwho

[more10]

In case you want to go 3-way (excuding sub) I have found the Altec audio-nirvana midrange driver for you:

http://www.ebay.com/itm/MATCHED-PAIR-ALTEC-755-E-8-SPEAKER-DRIVER-VERY-GOOD-COSMETICS-EXCEL-SOUND-/171233186726?pt=Vintage_Electronics_R2&hash=item27de4b13a6

/M

[gwho]

Have you tried this three way? I assume the smaller speaker goes up to a higher frequency. I thought the purpose of the two way was to eliminate a crossover over in the critical band for music. Doe the smaller speaker integrate better with the horn.

Thanks
gwho

[more10]

No I havn't tried any Altec drivers. I am a JBL-guy :-). First you try to put some damping material into the box. If you have problems with midrange output through the vents, you can try a threeway.

A threeway has a few advantages over a twoway:
1) No midrange through the ports
2) Smaller diameter cone will not beam as much as a large diameter cone and also it doesn't have breakup modes in midrange.

[gwho]

Thank more10! You had mentioned that the horn needs equalization. Could you name some reasonably priced equalizers that sound good. You had mentioned dbx, is this there analog equipment or digital devices. I've ordered the diaphragm from great plains. I will put stuffing in the 8256. Has anyone found any issues with the stock wire Altec used in the box? It is not the thickest wire. Also, I can't seem to find a schematic of the 1285-8B crossover. I'd like to change out the components (inductor and capacitors) related to only the 500Hz portion of the crossover to see how it sounds. The cap value is easy but I would like to know the inductor value (I don't have an lcr meter).

Regards,
gwho

[more10]

For testing you could go with a dbx 2231 (http://www.dbxpro.com/en-US/products/2231) or similar. I believe you will need about 18 dB span. Another interesting option is the miniDSP HD (http://www.minidsp.com/products/minidsp-in-a-box/minidsp-4x10-hd) (digital crossover). There are also some analog active filters with CD compensation, but its a gamble to use them with your horn.

You don't have to replace the inductors in you filter. Unless you think they are made of too thin wire.

[gwho]

I pulled the driver off of the horn to see what the problem might be. The dome looks good but it appears that the wire from the diaphragm is broken. I took a couple pictures. Is this something that can be fixed or is it fatal?

Thanks
gwho

6148361484

[Eaulive]

It can be fixed of course, but you have to have a good iron and a steady hand.... and work fast!

[gwho]

Could you tell me what the flexible wire is made from? Can you solder to it? Can I just bridge the two pieces or do I have to replace the entire wire? If I have to replace the wire where does it physically connect to the diaphragm? Is it where the glob of material is where the wire extends from the diaphragm.

Thanks for any help from anybody who has done this.
gwho

[Predrag Dukic]

Could you tell me what the flexible wire is made from? Can you solder to it? Can I just bridge the two pieces or do I have to replace the entire wire? If I have to replace the wire where does it physically connect to the diaphragm? Is it where the glob of material is where the wire extends from the diaphragm.

Thanks for any help from anybody who has done this.
gwho


The strip is made of berillium copper alloy. Should be easily solderable.
Simplest method is to solder the strip at the break.
That will allow You to determine if that is the only damage.

Thin solder blob is ok, but it will break again.
If You make a bigger solder ball at the solder point , it will last longer but
it might influence the sound due to increased mass of the dia.

You can also replace the strip with a piece of tinsel wire,
some dias have it originally, but that is risky operation...

[ivica]

Could you tell me what the flexible wire is made from? Can you solder to it? Can I just bridge the two pieces or do I have to replace the entire wire? If I have to replace the wire where does it physically connect to the diaphragm? Is it where the glob of material is where the wire extends from the diaphragm.

Thanks for any help from anybody who has done this.
gwho

Hi,

may be using several wires from the a piece of "desoldering wire"
http://bigdaddy-enterprises.com/images/braidwire.JPG
make a single wound and carefully solder.

regards
ivica

[Predrag Dukic]

Hi,

may be using several wires from the a piece of "desoldering wire"
http://bigdaddy-enterprises.com/images/braidwire.JPG
make a single wound and carefully solder.

regards
ivica

I think I have some tinsel wire (flexible wire that is made exactly for that purpose)
of the appropriate crossection. I just need the address.
Couple of inches should fit in a normal letter envelope...