Altec Lansing Milano...picked up today.

[Steve O]

The major benefits are to be derived from two upgrade paths known to me:

<snip>

2) Change the HF driver to BMS 4550/4552nd and use the stock crossover, or a newly built copy thereof, plus a simple compensation circuit as documented in the Valencia upgrade thread here on AK and at LHF. AK member Steve O is also finalizing his refinement of that work which may be available soon as an improved alternative. That's where I'd be going with these if I owned them:

<snip>
:

As noted by Mr. Zilch, I'm just about finished with my "refinement" of the upgrade that replaces the Altec HF driver with a BMS 4550 plus totally revised Xover inc MF equalization and driver/network impedance compensation. I've been listening to a "mock-up" of the final design as shown below. As you can see, it's not ready for prime time but it really sounds much better than stock.

I want some long term listening satisfaction with this before properly packaging the new Xover and converting the other speaker over to new design. If all goes well I should be able to wrap this up in the next month or so and will post documentation in a form that should be defensible.

 

[Zilch]

As a fellow tweak ... uhmm, crossover designer, I'm stepping up to say that's looking mightily good! :yes:

[We'll want to see plenty good curves 'n' stuff, of course, too.... ]

 

[dgwojo]

Those extra resistors look stock to me, maybe an attempt at using 16 ohm crossovers with 8 ohm diaphragms?? :scratch2: I've never run into anything like that before, we need another Milano owner to check his out!! Dave.

 

[avguytx]

I've really only checked the one speaker in depth but I would imagine both are the same. Who knows. It did almost look stock except for the wire nuts on the leads before the HF driver. The resistors are soldered into place on that little strip and it was done nice.

 

[Zilch]

Check the connection of the resistors next time you open one up, please.

I'm suggesting it's 3 Ohms in series with the red wire, and then the second resistor, possibly 15 Ohms, across the driver. 13.33 Ohms would be the correct value for a 4.08 dB attenuation @ 8 Ohms nominal impedance....

Those extra resistors look stock to me, maybe an attempt at using 16 ohm crossovers with 8 ohm diaphragms?? :scratch2:

Looks like a common generic terminal strip scabbed on to the compression driver hanger to me, Dave, with a two-resistor fixed L-Pad. If the factory did it, it was to bring the variable crossover attenuation into a desired range, maybe.

 

[Morden2004]

Yes. Those measurements were taken with the speakers leads from the amp disconnected. I haven't checked them on each driver but I think I will do that here in the next little bit for s**ts and giggles.

The horns are the 806-8A's.

Yeah, I wasn't really thrilled with the Valencia's and it's literally a night and day difference in the upper end response in these. It HAD to be that something was wrong with the 806-8A's in the Valencias I had. That and I just didn't want to go thru the ordeal of getting other diaphragms for them at that time, etc, even though they were in great shape. But, untouched, these sound better. But that's just me getting to compare from the only 2 sets I have had and I do realize they were darn near the same drivers/setup. :yes:

Did I mention I like these? I still have them playing in the opposite room that I am typing from! Once in awhile, I have to stop in there and sit for a moment or two.

This is a phenomenon that I too have noticed with (Altec) horns -- the sound is virtually as good around the corner in the next room as when parked in front of them. At first I found it spooky. Anyone else notice this?

Paul

 

[dgwojo]

2) Change the HF driver to BMS 4550/4552nd and use the stock crossover

Zilch,
Have you compared the sound differences of the 4550 vs the 4552?? :scratch2: I'm just wondering if the different magnet structure is worth $66 more per pair?? $120 each for the 4550 vs $153 each for the 4552ND. Dave.

 

[theophile]

Zilch has posted elsewhere that he has a slight preference for the 4552.

 

[avguytx]

Check the connection of the resistors next time you open one up, please.

I'm suggesting it's 3 Ohms in series with the red wire, and then the second resistor, possibly 15 Ohms, across the driver. 13.33 Ohms would be the correct value for a 4.08 dB attenuation @ 8 Ohms nominal impedance....

Looks like a common generic terminal strip scabbed on to the compression driver hanger to me, Dave, with a two-resistor fixed L-Pad. If the factory did it, it was to bring the variable crossover attenuation into a desired range, maybe.

And that terminal strip is riveted to the hanger, too.

Here are some observations upon taking the backs off to do some measurements. I added a couple of pics below for reference.

Left speaker:
DCR w/resistors in place and checked at terminal on back of cabinet = 10.4 ohm
DCR with resistors removed from HF driver and checked at terminal on back of cabinet= 7.8 ohm
DCR of HF driver = 6.7 ohm
DCR of LF driver = 7.1 ohm

Right speaker:
DCR w/resistors in place and checked at terminal on back of cabinet = 7.4 ohm
DCR with resistors removed from HF driver and checked at terminal on back of cabinet = 8.6 ohm (higher!)
DCR of HF driver = 6.9 ohm
DCR of LF driver = 7.0 ohm

So the drivers themselves are pretty much a match up but combined with the crossover network, L-pad, etc, the collectively read different.

It's been said earlier that these look like they've had insulation added to them. If so, both sides were done identical and the gray foam pieces were both stapled in place right behind the woofers. Also, since these are ported next to the horns, is there supposed to be that much insulation blocking the port? In my cabinet building experience, you typically don't want to block the port as it will change the tuning. It almost reminds me of an aperiodic membrane similar to what Dynaco used on their smaller speakers, although that wasn't Altecs intentions. Right?


Here is a closer picture of the resistor wiring.

Is this too much insulation? Am I losing low end?

 

[avguytx]

Man, I've gone thru some different femal vocalist CD's today of various genre's and these things are fun to listen to.

Zilch? Tom? dgwojo? etc? You guys around?

 

[Zilch]

Is this too much insulation? Am I losing low end?

Yes. That's wrong. Get rid of the foam and remove the insulation up at the ports. Leave the rest of the insulation in there, as it is adding virtual volume. The box is too small for those woofers, and adding volume is a good thing, however, retuning will be required to achieve the maximum benefit.

"Heavy" damping is typically 2/3 of the interior volume, and the ports should not be blocked. Whether that will work well with these Altec boxes and those woofers is unknown. BB6P can perform the calculations for retuning, but I'm at a loss as to how to actually do it with the "Beside the horn" ports. If you want to go that route, consider closing those up securely and installing conventional ducts on the baffle as in Valencia 846B.

Altec was not doing the Aperiodic thing, to the best of my knowledge. There was likely some open-cell foam on the front of the ports for aesthetics, is all.


******

Your photos appear to confirm my analysis of the resistors being a fixed L-Pad. Are they actually wired as I described above?

If so, my guess is that your crossovers do have the earlier potentiometer/resistor attenuation in them, and the L-Pad establishes the minimum attenuation of the adjustment range. Do the controls feel like pots (smooth, loose) or L-Pads (grainy, with a bit of mechanical resistance)? The rivetting evidences a factory install, in my view, unless they're just pop rivets, but it looks like a #6 hex nut in your pic to me, tho, with a too-short screw through the hanger from the "front" side....

Zilch,
Have you compared the sound differences of the 4550 vs the 4552?? :scratch2: I'm just wondering if the different magnet structure is worth $66 more per pair?? $120 each for the 4550 vs $153 each for the 4552ND. Dave.

As Theo says, I find the 4552nds to have a bit more clarity in the HF, possibly due to increased magnetic flux in the gap, though I haven't verified any of that. Member Jackgiff has modded two pair of Valencias, one pair with 4450s, and one with 4552nds. He reports that he cannot hear any significant difference. I use the 4552nds routinely on other waveguides because they are so small and light in weight, with essentially the same bandwidth as 4550. 1 kHz is low enough for most of what I do here....

 

[avguytx]

Yes. That's wrong. Get rid of the foam and remove the insulation up at the ports. Leave the rest of the insulation in there, as it is adding virtual volume. The box is too small for those woofers, and adding volume is a good thing, however, retuning will be required to achieve the maximum benefit.

That's what I was thinking too. It just looked like too much. It looks like 2 pieces of the insulation on each side of the horn. Should both be taken out on each side or just one piece?

"Heavy" damping is typically 2/3 of the interior volume, and the ports should not be blocked. Whether that will work well with these Altec boxes and those woofers is unknown. BB6P can perform the calculations for retuning, but I'm at a loss as to how to actually do it with the "Beside the horn" ports. If you want to go that route, consider closing those up securely and installing conventional ducts on the baffle as in Valencia 846B.

If that's an option to do, I am good to go with that. That would typically be a more precise tuning versus the "beside the horn" port. I will look closer at it and see if there is any possibility of the front baffle being able to be reomved...or at least the grill. If not, it's livable.

Altec was not doing the Aperiodic thing, to the best of my knowledge. There was likely some open-cell foam on the front of the ports for aesthetics, is all.

I didn't think so either. It just reminded me of that in a way.

Your photos appear to confirm my analysis of the resistors being a fixed L-Pad. Are they actually wired as I described above?

If so, my guess is that your crossovers do have the earlier potentiometer/resistor attenuation in them, and the L-Pad establishes the minimum attenuation of the adjustment range. Do the controls feel like pots (smooth, loose) or L-Pads (grainy, with a bit of mechanical resistance)? The rivetting evidences a factory install, in my view, unless they're just pop rivets, but it looks like a #6 hex nut in your pic to me, tho, with a too-short screw through the hanger from the "front" side....

They have more of a grainy, indented feel to them. And yes, they are tiny rivets.

Thanks Zilch. I'm going to remove some of the insulation and see what happens. I'm curious of the results although I kind of expect a little more full bottom end.

 

[avguytx]

Ok. Here is a picture with the insulation out that was beside the horn and the foam piece behind the woofer. One thing that makes me think that the insulation beside the horns could be "stock" is that they used the same large staples that are used for holding the insulation down on the back wall, too. Maybe that's coincidence...I don't know. But, the big staple does go thru both pieces that are on each side and the staples don't go too far into the side of the cabinet.

I attached a picture of the staples to show the size of them in relation to a standard size right angle pick tool.

I hate to remove the insulation from the other speaker until someone reads this and gives their opinion!

 

[Zilch]

Geez, your horn flanges aren't even bolted to the cab at the top. That certainly argues in favor of switching to 846B configuration with secure horn mounting and real ports below.

******

There's pics of port damping, if any, in the "Babies" thread at LHF. Hang on, I'll go have a look....

Here's one. There's at least one more:

http://audioheritage.org/vbulletin/showpost.php?p=182691&postcount=842

And here it is:

http://audioheritage.org/vbulletin/showpost.php?p=166744&postcount=784

Those are 846A Valencias. That's not to say Milanos weren't done differently, of course.

I think I'd at least have 1" fiberglass on the cab each side, top, and bottom, that "shelf" there. Altec was kinda stingy, looks like.

[BMS 4550 in both of those. Heh.... :yes: ]

 

[theophile]

Wow! That's weird.No bolts. :scratch2:
My Valencia 846As have one piece each of those little strips stapled where the ports are either side of the horn,not two,as was shown in your photos avguy.

 

[avguytx]

Geez, your horn flanges aren't even bolted to the cab at the top. That certainly argues in favor of switching to 846B configuration with secure horn mounting and real ports below.

******

There's pics of port damping, if any, in the "Babies" thread at LHF. Hang on, I'll go have a look....

Here's one. There's at least one more:

http://audioheritage.org/vbulletin/showpost.php?p=182691&postcount=842

And here it is:

http://audioheritage.org/vbulletin/showpost.php?p=166744&postcount=784

Those are 846A Valencias. That's not to say Milanos weren't done differently, of course.

I think I'd at least have 1" fiberglass on the cab each side, top, and bottom, that "shelf" there. Altec was kinda stingy, looks like.

[BMS 4550 in both of those. Heh.... :yes: ]

And from the looks of them, they've NEVER been bolted down as there are no screw marks on the horn. So what should I do for now? Leave the insulation out around the flange? The horn is pretty solid in there, I'll give it that, but it's wide open on the edges and around the top. So it was back loaded instead of front loaded like the Valencias I guess. It's almost like Altec had some really nice cabinets built to the right volume and then they made the baffle plates for the woofer/horn setup and stuck them in there. In looking at it, it wouldn't be that bad to build a new baffle for the woofer, and, port it if we can come up with the right port dimensions per the given volume. I can also build something for the upper section that would seal off the horn using MDF...no problem. I have the wood working tools to do it. (table saw, miter saw, air compressor, nail gun, etc, etc, etc)

Do you need to know the internal volume for calculating it?

Ok, what's this 4450? A different dome for the horn or a completely different driver itself? What's the advantages? I guess I better do some research on LH about those and look for your posts!

 

[Zilch]

So what should I do for now? Leave the insulation out around the flange?

What I said in the post you quoted, and I believe Theo just confirmed: put 1" insulation at the sides and across the top and on that plywood shelf below the horn.

With respect to reconfiguring the cabinets, you need the volume behind the horn as part of the total, so work out a way to mount the horn in its present location, but without openings through the front, i.e., sealing up the open areas. This may be as simple as installing new solid cleats all around to secure the horn.

Then, calculate the total internal cabinet volume. Again, the top section should be open to the bottom, as presently. From that, the box modeling software will tell us what size and length ports will be required to tune the system for the woofer. At that point, you'll try several options and pick what sounds best to you.

With respect to the high frequency, 806 drivers don't have it, so you need to either add a tweeter (which has it's own set of difficulties,) upgrade to later Altec drivers with Tangerine phase plugs, or abandon Altec compression drivers in favor of BMS, an inexpensive (and current) alternative which several members (and at least one loudspeaker design heavyweight) have used with considerable satisfaction. They won't sound like Altecs anymore, which, depending upon your perspective, may be a good thing. In any case, no irreversible alterations are involved in the upgrade; it's bolt on with new crossovers and listen.

If you like your Milanos the way they are, ignore all of that for now, and maybe consider at a later date.... :yes:

 

[avguytx]

Thanks Zilch. Yours, and everyone else's input, is always appreciated as you all are more the "guru's" on the horn speakers. I'm thinking about keeping them closer to what they are, for now, and do some minor things and go from there. I'll tell ya, I honestly like the top end on these as they sit. Now, I could do with a little more low end but it's not awful. Would I benefit in building a new crossover network from scratch with new L-pads at this point? That's not getting too far into it plus it would keep the stock one there for collectibles sake. Since this crossover is completely sealed, you just can't go in and change a couple of parts that easily...obviously.

Man, I must have gone thru all 5 Diana Krall CD's that I have on these things. It's very easy to just sit and listen to them. Maybe one day I can do other things to the speakers and get them to another level. But right now, I need to get some better stuff behind them like a nice little tube amplifier and sources. I'm selling a pair of my other larger speakers just to fund an amp for these. Hell, I have too much stuff around here doing nothing anyway.

Thanks again....always appreciated.

 

[Zilch]

Yes, build new crossovers according to the original design. :thmbsp:

I'll tell ya, I honestly like the top end on these as they sit.

Theo and a bunch of others like the "stock" sound as well. I have no dispute with any of that; I just put forth alternatives for consideration, now or later, if desired, is all.... :yes:

 

[avguytx]

The crossover that you attached on post #34 of this thread, right? I was looking at that earlier and had a questions about the caps. I see that the LP and HP both use the same inductance but they differ on the capacitance. Does that give it some sort of "gap" in the crossover point instead of them overlapping?

I like these simple 2-way 12dB/octave crossovers! Easy on parts! Any particular type or brand of caps that people seem to like the best to use?