What to do with Altec 515b and 288-8g on 805b horns

Good day,

Am a newbie here. Im from Manila, Philippines. Need some help from the gurus here who are knowledgeable on Altecs. Recently (and cheaply)got a pair of 515b drivers (16 ohms) and a pair of 288-8g (8 ohms) on 805b horns. Can anyone suggest what cabinet design and crossover design is suitable for the mentioned drivers. I'm not so sure if the Altec A5 (828b or 825) enclosure design would do. Also what dividing network will work on this? Im a dimwit with technical stuff but I do have good hands for cabinet making.

Another question is, since the HF driver is 8ohms and the LF driver is 16ohms, what can I do about it? My guess is is that the pair 515b drivers were initially just for one speaker connected together to make it 8ohms. The other pair must have been sold somewhere else. Is there a way to use the LF and HF driver with different impedance?

Would appreciate your help.

Many thanks,
Earl

Please be kind to the new fella, i steered him here for the premier in Altec guidance.

Welcome eestrera! :welcome:

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Originally Posted by bowtie427ss

Please be kind to the new fella, i steered him here for the premier in Altec guidance.

Welcome eestrera! :welcome:

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Thank you very much sir. :thankU:

Hello Earl and welcome.
I'm no expert but have s similar set of drivers and use them in an A-5 configuration, with readily available (epay, CL, Kijiji) 828/825 cabinets.
The impedance differences could be addressed by swapping out voice coils in the HF units to match those of the woofs, or by bi-amping into an electronic (active) crossover.
Series or parallel resistors of the appropriate value coukld be placed around/in-line with the 16-ohm units so the amp "sees" equal nominal impedances on each driver if still using a passive network.
Others may jump in here to correct me or offer more specifics, but I have a good sounding setup of A-5's with 515-8G's, 288-8L's, and 1005B horns, through N-1285 networks. Sounded really nice this Wednesday afternoon past at my clinic's summer BBQ at my place. Low volumes but effortlessly portrayed outdoor musical imagery from 200 feet away.
Jon Archibald
Ontario, canada

Again, location would be helpful.

One of my local friends has several A7/A5 type cabinets he's trying to sell.....

First off Welcome to the board Earl, :welcome: I think you maybe right that there was another set of drivers.Is picking up another pair of 515B's an option for you.You can hook up a pair of 16 ohm drivers to produce an 8 ohm load.The 288's with a single woofer configuration can overpower the woofer quite easily.It is an ideal situation to use 2 woofers with a 288-8G per side.Is cabinet size a restriction.Or do you have space requirements/restrictions.The more detail you can provide the better your questions can be answered.Be patient there are many knowledgeable and good people here.

Kind Regards ~ AB

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Originally Posted by aeyb701

Hello Earl and welcome.
I'm no expert but have s similar set of drivers and use them in an A-5 configuration, with readily available (epay, CL, Kijiji) 828/825 cabinets.
The impedance differences could be addressed by swapping out voice coils in the HF units to match those of the woofs, or by bi-amping into an electronic (active) crossover.
Series or parallel resistors of the appropriate value coukld be placed around/in-line with the 16-ohm units so the amp "sees" equal nominal impedances on each driver if still using a passive network.
Others may jump in here to correct me or offer more specifics, but I have a good sounding setup of A-5's with 515-8G's, 288-8L's, and 1005B horns, through N-1285 networks. Sounded really nice this Wednesday afternoon past at my clinic's summer BBQ at my place. Low volumes but effortlessly portrayed outdoor musical imagery from 200 feet away.
Jon Archibald
Ontario, canada

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Thank you for the warm welcome and thanks for the tips. Just some q's sir, . I wanted to keep the drivers as original as possible, (Im a nostalgia freak and love vintage audio) would swapping the voice coils in the HF driver change the original t/s parameters? The active crossover looks like a better alternative for me but am open to options.
The series and parallel transistors also seem to be less intrusive.

Do you have a photo of your current A5 setup? Would love to see it.

Btw, I've read that these drivers can be powered by flea powered tube amps, do you think its possible to run them via triapath t-amps?

Thanks,
Earl

Welcome to the forum!

I also run the A5 - but have 8 ohm woofers and 16 ohm drivers on the 803 horns.
But that is not a problem, as long as you are building your own crossover. If you are trying to use an already built crossover, it would be a problem. Look at the Hiraga crossover for the A5. Use the 8 ohm section for your horns, the 16 ohm section for the woofers. You will have to adjust the resistors on the horn, but we can help with that.

Yes, you can run these with a T-amp. I have quite a collection here and they all do well.
I am the t-amp guru, after all. ;)

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Originally Posted by analog addict

Again, location would be helpful.

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Earl is in the P.I.

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Originally Posted by Altec Best

First off Welcome to the board Earl, :welcome: I think you maybe right that there was another set of drivers.Is picking up another pair of 515B's an option for you.You can hook up a pair of 16 ohm drivers to produce an 8 ohm load.The 288's with a single woofer configuration can overpower the woofer quite easily.It is an ideal situation to use 2 woofers with a 288-8G per side.Is cabinet size a restriction.Or do you have space requirements/restrictions.The more detail you can provide the better your questions can be answered.Be patient there are many knowledgeable and good people here.

Kind Regards ~ AB

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Thanks for welcoming me on the board. Getting another pair was my first instinct. However, after doing some research and seeing the photos and measurements of the cabinets with the dual 515bs, I think my wife will kill me. And I don't want to be sleeping in the garage. My listening room is rather small at around 15ft wide and about 18ft long. Aside from the size, the prices on the 515b's here in my location are priced around 30x more the price I got it for. I've shown her the A5 dimensions and it seems passable to her for now. I'm slowly getting her into this hobby so WAF is a big consideration. Once shes addicted, things will be easier:D

If the 288 horn with a single 515b configuration is to overpowering, can this be fixed by havng an active equalizer?

Thank you for help. WOuld love to hear more from you guys.

Thanks,

Earl

Yes, the horn can be EQ'd actively or passively. You'll want to...

For a bass box you might also look at the Onken box. It works very well with the 416. Should do OK with the 515. GM might know. I can send you the plans, if you don't find them. No horn flare, so easier to build then the Altec box. Looks cool, too.

The Onken looks like this. Onken Box

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Originally Posted by Panomaniac

Welcome to the forum!

I also run the A5 - but have 8 ohm woofers and 16 ohm drivers on the 803 horns.
But that is not a problem, as long as you are building your own crossover. If you are trying to use an already built crossover, it would be a problem. Look at the Hiraga crossover for the A5. Use the 8 ohm section for your horns, the 16 ohm section for the woofers. You will have to adjust the resistors on the horn, but we can help with that.

Yes, you can run these with a T-amp. I have quite a collection here and they all do well.
I am the t-amp guru, after all. ;)

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Thanks for the warm welcome. In your A5 configuration, is that an active crossover? I've managed to download the Hiraga crossover plan and I'm still trying to undertand it. It has a design for the 8 ohm crossover and the 16 ohm crossover, so do i use the 16 ohm design for the 515 and the 8 ohm design on the 288's? Will both crossover get linked to each other in one way or another or do the go to separate amplifiers respectively? And what kind of adjustment do you do with the resistors sir? Sorry having so many questions, still trying to understand.

Would you mind sharing what t-amps your using sir and how you use them on the altecs? I'd be very interested to know. For testing if the drivers work, i just used a pair of the original sonic impact 2 amp recased and reconfigured with new output transformers and caps. Somehow I always felt safe using this low powered tripath amplifiers is testing drivers compared to my solid states. Was planning on ordering a pair of some Dayton t-amps over parts express and experiment on using them as a 2nd setup to run the Altecs. The pop pulse is also readily available in my area though I haven't auditioned one yet.

Thanks.

Regards,

Earl

Hi Earl, glad to help. And it is a subject that I know something about!

I was using an active crossover, but now am running passive and prefer it for many reasons, not the least of which is ease of use.

The passive crossover comes after the amp, so you need only one amp. The 2 parts will be link together, but they don't really work together, that's why you can mix and match. I'll look at the design again, but I think you need only change 1 resistor value. Might put a variable resistor in there to "tune" it. That would allow you to bring the level of the horn up or down to fit your room. The crossovers will not be cheap to build, inductors are expensive, but it will serve you for years and will sound great.

As for T-amps, I have too many. Sonic impact 1 & 2, Super-T, Fenice, Virtue Audio 1 & 2, Pop Pulse, 41Hz, Sure, Trends, various Chinese, etc. They all work fine with the A5.
One problem you will have is the 16 ohm woofer. It requires a higher voltage to get 1 watt than an 8 ohm woofer. And many of the T-amps are voltage limited as they run from 12V. That will limit your peak power a bit. Like 6.5 watts peak. But that would be rather loud with the 515 anyway!

What do you guys think about using the 816 enclosure for the 515b?http://www.hostboard.com/forums/hbmc...2010/06/13.jpg
This one is from simplex audio. With nice wooden horns too.http://www.simplexaudio.net/RIGHT.JPG

I don't think you'll get much bass out of it. The 515s need a big box.
But someone here should have experience with this combo and will chime in.

It's my understanding that 60-70Hz is about the best you'll see from this combo. I have a set of 515-16GHP in 816VI's. They are essentially a sound reinforcement system from a school auditorium. Great for vocals and PA system material, not so good for bass.

A sub woofer is recommended for audio applications.

Panamaniac, Analog addict,

Thanks for the inputs on the 816. Do you guys have the enclosure design for the Onken using the 515b's? Tried looking for it but all i get are photos.

Thanks,

Earl

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Originally Posted by analog addict

It's my understanding that 60-70Hz is about the best you'll see from this combo. I have a set of 515-16GHP in 816VI's. They are essentially a sound reinforcement system from a school auditorium. Great for vocals and PA system material, not so good for bass.

A sub woofer is recommended for audio applications.

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For some reason the 9864-8A which also uses the 816-VI cabinet and a 515 based Duplex is supposed to be able to reach 50hz. I spec sheet for just the cabinet claims 65hz, as you stated. Maybe the 50hz is a stretch? My 9864 is very listenable, but does lack deep bass. I think the cabinet is a great alternative to the 825/828 cabinets. Having said that, I've never had the opportunity to listen to the earlier 816 cabinets. Another thing to consider is the differences between a 515B and our later drivers.

What I've always loved about a Front loaded Bass Horn is the dynamic impact of available low frequency .......... You can't get that with, no box!

Have fun!
Willie

Hey Earl. All the info you need is in the link I posted above.
Onken 360l Enclosure with Altec 416 drivers
Check out the linked articles at the bottom of the page. Plans are within those links.
Onken Plans

There is a google translation button on the French pages. It does a decent job. Since I was around when those boxes where built and the articles written, I can help if there is something you don't understand.

This box is meant for the 416, but the 514 should be OK in it. Maybe a little less bass, but better dynamics. And you can always swap in a pair of 416s later, if you find a pair or trade your 515s for them. This is a great bass box, despite its odd design. It has won fans the world over.

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Originally Posted by Panomaniac

Hey Earl. All the info you need is in the link I posted above.
Onken 360l Enclosure with Altec 416 drivers
Check out the linked articles at the bottom of the page. Plans are within those links.
Onken Plans

There is a google translation button on the French pages. It does a decent job. Since I was around when those boxes where built and the articles written, I can help if there is something you don't understand.

This box is meant for the 416, but the 514 should be OK in it. Maybe a little less bass, but better dynamics. And you can always swap in a pair of 416s later, if you find a pair or trade your 515s for them. This is a great bass box, despite its odd design. It has won fans the world over.

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Interesting.

I didn't mention it here because this is the "Altec" place, but over at the "other place" this was in my very first post to the OP:

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If i had these drivers, i'd look for something that has better LF performance than 825/828, maybe an Onken or something similar.

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:D

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Originally Posted by Panomaniac

Hey Earl. All the info you need is in the link I posted above.
Onken 360l Enclosure with Altec 416 drivers
Check out the linked articles at the bottom of the page. Plans are within those links.
Onken Plans

There is a google translation button on the French pages. It does a decent job. Since I was around when those boxes where built and the articles written, I can help if there is something you don't understand.

This box is meant for the 416, but the 514 should be OK in it. Maybe a little less bass, but better dynamics. And you can always swap in a pair of 416s later, if you find a pair or trade your 515s for them. This is a great bass box, despite its odd design. It has won fans the world over.

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Panomaniac,

Thanks. Got it. Sorry never bothered clicking the bottom part in french. Turns out thats where the plans are. Thanks for pointing it out. Will study it. Looks like a simple cabinet to build which just needs decent finishing to make it look beautiful.

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Originally Posted by bowtie427ss

If i had these drivers, i'd look for something that has better LF performance than 825/828, maybe an Onken or something similar.

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See, damaged minds think alike! ;)

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Originally Posted by eestrera

Looks like a simple cabinet to build which just needs decent finishing to make it look beautiful.

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It's not too hard. A lot of work, a lot of parts, but not hard. I'd like to build a pair out of bamboo plywood. That would be killer. Easy to finish and looks great. Even smells good. The end grain is very pretty, too, so no need to hide it. But $$$.

If you do one, put the damping in a curtain about 1/3 of they way back. Works better than on the back wall. Front or back panel removable, does not matter. Just depends on if you like to see the screws or not.

What about an Onken W box. I like dual woof's with any Large format driver.

TWOGOODEARS - ??????????: ... again about Goto speakers from Japan: visiting my friend Toni and listening to his system

Well I just so happen to know the Onken W box very well indeed. It's amazing, truly amazing. But it's huge and very, very heavy. Double walled, sand filled construction. Even I am not that dedicated. But man, is it ever clean.

You'll end up spending a lot of money on an amp to run the Onken-W. Why? Because you can hear every little flaw in your bass amp. It has to be top notch or you will always be bothered by some little "something."

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Originally Posted by Panomaniac

See, damaged minds think alike! ;)



It's not too hard. A lot of work, a lot of parts, but not hard. I'd like to build a pair out of bamboo plywood. That would be killer. Easy to finish and looks great. Even smells good. The end grain is very pretty, too, so no need to hide it. But $$$.

If you do one, put the damping in a curtain about 1/3 of they way back. Works better than on the back wall. Front or back panel removable, does not matter. Just depends on if you like to see the screws or not.

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I was also thinking of bamboo plywood/plyboo because aside from aesthetics, I've always felt like bamboo was musical and had good acoustic properties. It claims to be harder than oak while still retaining some amount of flexibility. Too bad there non are available here in our area and the closest on to import is from China. What is available though are laminated bamboo panels, crushed bamboo or strips laminated into a piece of plywood as a veneer. Looks pretty good to.

For inside cabinet damping, has anyone tried dynamat? The one they used in the car doors for car audio?

Thanks,

Earl

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I was also thinking of bamboo plywood/plyboo because aside from aesthetics, I've always felt like bamboo was musical and had good acoustic properties. It claims to be harder than oak while still retaining some amount of flexibility. Too bad there non are available here in our area and the closest on to import is from China. What is available though are laminated bamboo panels, crushed bamboo or strips laminated into a piece of plywood as a veneer. Looks pretty good to.

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In most cases an acoustically "live" material is the last thing you want to construct loudspeaker cabinets from.

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For inside cabinet damping, has anyone tried dynamat? The one they used in the car doors for car audio?

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Probably cost prohibitive for the quantities needed in a large wooden box, at the very least i expect the cost well exceeds the point of diminishing returns. I'm a big fan of well secured fiberglass, there's probably more than one reason it's been the standard for decades for most manufacturers.

Now, Dynamat for damping the small format horns OTOH, i think it's the perfect material for this job, just don't apply it to anything you might ever want to remove it from.

Just my .02...................

Bamboo ply isn't all that live. No worse than birch, as far as I could tell. Much denser. And what colorations it has are not unpleasant. No real research here, just my experience.

100% Wool felt is the way to go. But it is expensive and sometimes hard to get. There is a nice new cotton insulation on the market that I've heard in action and was quite impressed with. Bonded Logic makes it in the USA.

But yeah, I use fiberglass. =) Cheap and easy to find.

Hi Guys,

I am almost complete with my A7 cabs and I understand that the best this cab will do is 50 cycles or so?

My thoughts on this have lead me to consider 'retuning' the bass chamber after all the removeable board(s) on the front lend themselves to experimentation on box tuning.

My reasoning is that the A7/A5 bass bin is great as it has the midhorn and time aligns the woofer to the horn compression driver - well worth keeping?

The mid horn will bring the efficiency of the woofer up a tad to better match the comp driver and thus allow less attenuation on the comp driver?

Now given that I am new to Altec VOTs I am sure that someone else has considered this and even implemented?

Earl, I believe the A7/A5 is worth looking at for these factors, but I am no Altec Guru - keen to hear what others think

Winders

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Originally Posted by Panomaniac

There is a nice new cotton insulation on the market that I've heard in action and was quite impressed with. Bonded Logic makes it in the USA.

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That's the stuff that I've wanted to try for awhile.

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Originally Posted by Panomaniac

See, damaged minds think alike! ;)

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I'm damaged too... ;)
But seriously, some simple factors:
1) volume
2) frequency
3) dynamics
4) cross over range(I like to think of it as Kashmir) ...(horn/compression driver and speaker system reproducing the same frequencies)

I can't imagine an onken touching an a5 with regards to #1 or #3 or #4.
Am I wrong? Or mostly wrong? a little more damaged? :)

It's quite good. My buddy Gary Pimm in Portland turned me on to it. He puts it to good use. It's good stuff, if you'll pardon the pun.

Welcome to Gary Pimm's DIY Page

Hard to say, Steve. I've heard both, often - but never A/B. The Onken is a real joy. It's super clean, and has decent bass. Bass that sounds like bass, not just thump. Like on some classical recordings you can hear and almost feel the air handling in the recording venue. Very dynamic, too. I haven't met anyone who didn't like it.

But the A5 is darn good too. Seriously reworked, it's masterful. Obviously I love it, that's what I own - and what I wanted to own. But I think it's easier to get to excellent results with the Onken than the Altec 828 box. A least that's my feeling. If I had not bought the A7s from Old Guy, I would have built an Onken box. No way would I undertake 828 construction! They may be more alike than different, really.