OK, now you got me started. Here's an old link to where I started with 604s most of it still seems relevant.
http://www.wardsweb.org/Billfort/
Since first hearing Altec 604s, I've been hooked they just have this amazing mix of strengths that let me see past their shortcomings and for low power SETs in regular sized rooms, I find them hard to beat and after 12yrs of listening to alternatives at shows, in showrooms and others systems, I can't think of anything I'd trade them for.
They are good at;
604E
The 604E is pretty plentiful out there and I love these especially in the mids where I think they might just be the best of the lot. They don't go as low as the 8Gs and may not be as extended on top as a Tangerine'ed G or H, but they are close, and hey, those mids! I heard these in massively built (1-1/2" thick HDF) cabinets and nicely done Baltic birch 620A cabinets and I think the BB 620As (or a derivative) is the way to go the HDF just seemed to knock some of the life out of them. I haven't seen a 'Markwart' version of a crossover for these but would seek out or build a Mastering Labs crossover they sound incredible with the ML.
604-8G
The 604-8G is where I live and most of my opinions on 604s should be taken in this context. I've built a complete system and even a room around getting the most out of this version while pushing back the negatives so I'm a little biased. I think these strike a nice balance between the syrupy sweet Es and 'technically' better performing H but I don't see any of these as the winner they are all good. Mine might be a kind of bastard child actually they have the earlier compression driver covers of the E but have the 'later' Tangerine phase plugs, while most of the Gs I've seen have the same covers as the H below. Not sure what this means but since I bought these off a guy who bought them new, I know they are something 'factory'.
604-8H
In the H we have the newer Manteray true horn not the sort of 'fake sectional' of the E & G where the section vanes don't go all the way back to the throat. I would jump at a pair of these as they might just have the best performance potential and I've certainly liked what I've heard from them.
Great Plains Audio.
If building a pair of 604 speakers, 'used' might work out great it sure did for me. The above are rare alnico classics though that can be a real crap-shoot (especially now that the internet means supply-and-demand pricing) but Great Plains can keep them alive. They can re-charge those alnico magnets, re-cone the woofers with the correct parts and materials and supply the right diaphragms (I have GPA diaphragms in mine).
But if I was starting new, I would probably consider buying the brand-spanking new GPA 604-8H III (FerriteV magnets) or what would be my preference the alnico 604E Series II. I think I'd even consider the GPA crossovers for these but I'd leave them outside the cabinet I'd want to at least be able to try a Markwart crossover, which have been a key ingredient in what I now listen too. Not sure of the current pricing from GPA but I think new drivers and crossovers would be around $2k the same I bet you 'd pay for good (and risky?) old drivers on the used market.
I'll go on about cabinets and crossovers next if you can stand this rambling.
http://www.wardsweb.org/Billfort/
Since first hearing Altec 604s, I've been hooked they just have this amazing mix of strengths that let me see past their shortcomings and for low power SETs in regular sized rooms, I find them hard to beat and after 12yrs of listening to alternatives at shows, in showrooms and others systems, I can't think of anything I'd trade them for.
They are good at;
- imaging their point-source design just gets this right with lots of depth and accuracy
- dynamics a major one here, Altec 15" woofers and horn loaded compression drivers excel at this.
- Sensitivity my G's are about 100db/watt efficient which gives you lots of amp options like like the low power SETs I love.
- Tone I don't know if it's just the Altec driver recipe or some kind of alchemy thing going on with these alnico drivers and the simple SET circuits I use but they seem to get this very right.
- Design & use flexibility kind of a 'sort of' here but they DO work in regular sized rooms (I once used mine in an 11 x 12 room). They are big drivers and you won't take them far in a small box but if you are creative and use something like a corner cabinet, well, mine took up less of the room pushed into the corners than the stand-mounted mini-monitors they replaced. I have yet to hear a more conventional partially horn loaded speaker that works as well as these in small to midsize rooms.
- being small they are huge, I get it.
- Deep bass even the ones likes the Gs onward that are more TS loading friendly are only going to get down to the mid 30s, and that's in huge >9cu. ft. boxes.
- Mid-range performance a huge 'depends' here and through careful cabinet & crossover design and a good dose of tweaking all the way from the drivers through the system to the room, I feel they can have stellar mid-range. But compromise on the cabinets, crossover, hook them up to the wrong system or use them in a bright, untreated room...ice-pick in the forehead, in-your-face, fatiguing, all kinds of bad stuff.
- Treble extension. - these are 1" compression drivers that just don't play that high the newer flavors with the Tangerine phase plugs are 'supposed' to go higher and crossover design helps here but don't expect extended highs beyond say 15kHz (for Tangerine Gs anyway). To me, they are just right and some try 'add-on' tweeters to go higher but I've never liked the results kind of hurts the 'whole-ocity' (Gizmo Rosenberg term) of the 604.
- Price and availability they are highly sought-after antiques, and since the results seem to prove out 'you get what you pay for', you usually have to pay. Luckily, they are still being made the right way by Great Plains Audio and their versions might even be better than the used/abused ones out there so this is a very good thing - but still expensive.
604E
The 604E is pretty plentiful out there and I love these especially in the mids where I think they might just be the best of the lot. They don't go as low as the 8Gs and may not be as extended on top as a Tangerine'ed G or H, but they are close, and hey, those mids! I heard these in massively built (1-1/2" thick HDF) cabinets and nicely done Baltic birch 620A cabinets and I think the BB 620As (or a derivative) is the way to go the HDF just seemed to knock some of the life out of them. I haven't seen a 'Markwart' version of a crossover for these but would seek out or build a Mastering Labs crossover they sound incredible with the ML.
604-8G
The 604-8G is where I live and most of my opinions on 604s should be taken in this context. I've built a complete system and even a room around getting the most out of this version while pushing back the negatives so I'm a little biased. I think these strike a nice balance between the syrupy sweet Es and 'technically' better performing H but I don't see any of these as the winner they are all good. Mine might be a kind of bastard child actually they have the earlier compression driver covers of the E but have the 'later' Tangerine phase plugs, while most of the Gs I've seen have the same covers as the H below. Not sure what this means but since I bought these off a guy who bought them new, I know they are something 'factory'.
604-8H
In the H we have the newer Manteray true horn not the sort of 'fake sectional' of the E & G where the section vanes don't go all the way back to the throat. I would jump at a pair of these as they might just have the best performance potential and I've certainly liked what I've heard from them.
Great Plains Audio.
If building a pair of 604 speakers, 'used' might work out great it sure did for me. The above are rare alnico classics though that can be a real crap-shoot (especially now that the internet means supply-and-demand pricing) but Great Plains can keep them alive. They can re-charge those alnico magnets, re-cone the woofers with the correct parts and materials and supply the right diaphragms (I have GPA diaphragms in mine).
But if I was starting new, I would probably consider buying the brand-spanking new GPA 604-8H III (FerriteV magnets) or what would be my preference the alnico 604E Series II. I think I'd even consider the GPA crossovers for these but I'd leave them outside the cabinet I'd want to at least be able to try a Markwart crossover, which have been a key ingredient in what I now listen too. Not sure of the current pricing from GPA but I think new drivers and crossovers would be around $2k the same I bet you 'd pay for good (and risky?) old drivers on the used market.
I'll go on about cabinets and crossovers next if you can stand this rambling.