Have you built the Markwart crossover for 604 8G/8H ??

**SD-50** · January 31st, 2017, 07:45 PM

Originally Posted by rogerh113

Hi,

I think all of the input is useful, particularly as I like to methodically plan my work so there are no (or reduced) surprises. I actually expect the tuning of the speakers to be an iterative process. I probably will start to address the most annoying aspect of the sound first (boomy bass or missing/overly aggressive highs). The extra wild card, aside from the high end tuning and port length, is the impact of the wooden Magnificent grills (assuming I can repair them, which I think I can). I have to assume that there will at least be a high end impact, and possibly some bass impact, from the grills. I should be able to determine that by leaning the grills against the face of the speakers. I have a feeling I am in for a lot of back and forth testing, and trying to figure out what sounds best relative to what I can realistically get away with (wife probably fine with grill cloth and maybe wooden grills, but possible not big naked speakers in the living room). I'm guessing the big naked speakers will sound best..... One good thing is that it generally does not take me a long time to figure out what I like sound wise (generally just minutes). I do understand that there is some break in time for the PIO caps, so patience will probably be required. I have done none of this before, so it will be a grand adventure.

Laying out the crossovers now, but probably at least a month before I a well enough to start working on the speaker cabinets again. I almost have the second cabinet deconstructed, and after that I get to actually start building the cabs up. Really looking forward to it.

regards -- Roger

Would enjoy seeing some pics of the XO as well as the speakers.
Cheers

**rogerh113** · January 31st, 2017, 08:59 PM

I will certainly post pictures as I go along. To frighten all off, here is a picture of my starting point. The other Magnificent was treated just as well as this one was. No drivers, etc. I really liked the idea of saving these from the landfill. Really solid walnut ply and some serious patina (hopefully much of which will refinish away).

The first cab came apart perfectly, and the second is mostly there (probably 2 hours left). I'll have intact sides, and plenty of width on the top, bottom, and base to do what needs to be done.

With a bit of reduction in width and depth, and the insertion of a baffle and center brace (both using dado/rabbit joints), it will hopefully be a pretty solid 9 cuft 604 enclosure..... Looking to have full Magnificent height, with internal width of 22 inches and internal depth of 18 inches. Given my limited facilities and equipment, I anticipate glue-up to be a pain, but I will just have to figure out how to methodically work my way through that.....

Lots of little details to make it right, but I have been pondering this for a while and feel I have a pretty good grasp on what I need to do.

regards -- Roger

**Elitopus1** · February 1st, 2017, 01:04 PM

I definitely would have grabbed those too! The one in the pic looks in really decent shape. Maybe someone sold the drivers that were in them and then dumped the cabs?

Man I would love to be able to get my hands on some of these factory cabs that are being tossed. Like most of us, I have more extra drivers than complete speakers. I could probably build a few pair right now

And since we are talking about bypass caps, has anyone ever used any of the more industrial types? There are some nice, high voltage caps at Mouser. Like the DC link and snubber caps. 3-5 bucks for a PP cap .1-.22uf that handles 1kv-3kv.

**BillWojo** · February 1st, 2017, 06:00 PM

I have no idea on those really high voltage caps. I do intend to try out some vintage oil filled caps, most of them are rated at 600V. I've had to parallel them up to get all my values, 4 + 2, 4 + 4, 10 + 6, that kind of stuff. Going to take a box to hold them all. Plus I have a bunch of 0.5 and 1 values. It was good hunting at the flea market this year.

BillWojo

**Phil-G** · February 1st, 2017, 09:26 PM

Originally Posted by Elitopus1

I definitely would have grabbed those too! The one in the pic looks in really decent shape. Maybe someone sold the drivers that were in them and then dumped the cabs?

Man I would love to be able to get my hands on some of these factory cabs that are being tossed. Like most of us, I have more extra drivers than complete speakers. I could probably build a few pair right now

And since we are talking about bypass caps, has anyone ever used any of the more industrial types? There are some nice, high voltage caps at Mouser. Like the DC link and snubber caps. 3-5 bucks for a PP cap .1-.22uf that handles 1kv-3kv.

there's a pair in cape coral.

**Elitopus1** · February 1st, 2017, 10:32 PM

Originally Posted by Phil-G

there's a pair in cape coral.

Yeah but those are 1,600$. And they still have drivers!

I want some cabs that are in good condition and free

**rogerh113** · February 1st, 2017, 11:23 PM

Well, mine were not exactly free..... $100 delivered for the pair. Not bad to my mind. The sellers had sold the drivers to a guy in the midwest who really wanted the cabs too, but shipping was outrageous. The sellers were desperate to get the big cabs out of their house. Probably could have negotiated them down, but that seemed kind of petty.

regards - Roger

**Elitopus1** · February 2nd, 2017, 09:54 AM

I would have bought those for 100$. I paid twice that for my 828 cabs. And they were in worse shape.

I need to befriend a flipper so I can get his throwways

**rogerh113** · February 2nd, 2017, 11:05 AM

Actually I think there is a lot to be had out there in the way of large cabinets. I was tracking Craigslist for less than a month before these came up. The big problem is searching Craigslist effectively, since the search terms are VERY PICKY. If the search terms are not an absolute exact match, you will miss the item. I almost missed these - did an oddball search and they popped up - not in Altec cabinets, or vintage Altec, since his verbiage was just a little different. You can also put a 'wanted' ad in Craigslist and troll. Somebody with big cabs clogging his storage unit would be happy to see that ad.

I think almost nobody wants big cabinets any more - they want the sleek, skinny, trendy decorator speakers. I am sure these cabinets would have been in the landfill in a week or two if I had not purchased them. The guy had no idea why I would want to buy them (but was happy a loony came his way).

regards -- Roger

**Elitopus1** · February 2nd, 2017, 12:28 PM

I've been running a "WTB" ad on my local CL for over a year. I have had some good scores through that. Mostly crap though.

The vintage audio market is dead in my area. I get most of my junk from the surrounding, bigger cities.

Btw, you are a lucky guy if your wife lets you bring those magnificents inside the house. All my big speakers live out in the man cave. I have some small DIY Altecs inside. It kind of works out having the speakers in my own space. I have acousically treated that room in a non-waf friendly way