Save cabinets - spend more than they're worth! Annoy wife!

[tlparker]

Just to be clear from the beginning, these made it into "our" possession via marriage, I did not purchase them. They're your typical $400 or so a pair (they're 10 years old) floor-standing Advent speakers which are about 40" high, 19" wide, and 24" deep (external dimensions, I'd subtract about an inch all the way around for volume).

I had 'em hooked up as the "music rears" on my Denon 3805 and eventually started blowing the woofers ones by one. Their arrangement is very simple straight vertical line with 3.5" tweeter near top, then two 8" active woofers/drivers, then one "passive" woofer (the old "you don't need to electrify 'em to make great sound out of that other 8" hold, though I doubt they ever mention to buyers that the bottom one was not powered). (Side note: I made a pair of speakers using large 10" "electricity free" woofers in the early 80's and they sounded quite good, though I don't see the practice used much any more).

So one day I took the fronts off to see how bad the damage was and out of the 4 "real" woofers, 3 were visibly torn from their surroundings. Not a single speaker had any mfr or ratings type information on it that I could find.

The thing is, the cases on these babies are in great shape. Heavey, 3/4" MDF, reinforced at top and bottom with standout laminated pieces which have curves that the grill fits into. All the exterior edges are rounded over and there isn't a scratch on them or a tear on the grill fabric.

So in a crazy night of insanity, I hopped on Parts Express and started trying to pick out speaker and crossover combinations that would work. Existing openings limited me a fair amount as you don't want to make the woofers much bigger and the tweeker openings can handled up to about 4" rear-mounted. And yet, I was getting more and more frustrated with the few options I could come up with. Since this was a "makeover", I decided I wanted to buy the best I could that would fit in the current openings be compatible with the cabinet size I was working with, try to come up with decent hz ranges and overlaps that I could find/make a crossovoer to work with. Though I went high-end on the drivers, as I was kind of counting on them to support the whole system.

From a sound design perspective, my intent was to create something that would work well in a 7.1 surround sound configuration (broad spectrum ambient noise), but also provide butt-kicking "7 stereo" support to go with my Paradigm 100 fronts/centers and Polk di/bi-pole surround sides (which, BTW, do a heck of a job with the music, I bought 'em for surround sides, but they're Fxi30's and sound fantastic when I'm cranking out the amps).

Here's what I embarassingly ended up with:
- Heavy Duty Titanium Super tweeter (p/n 270-135)
- Davis 20gklv8td8f 8" driver (p/n 297-572)
- Dayton RS225s-8 reference series woofer (p/n 295-366)
- Silenium 8pw3-slf 8" driver (I considered this more of a driver/woofer or possibly something I try interchanging with the Dayton and use whichever works best and save the other for another project -- those Dayton's weren't cheap)

Also, they had thrown in a 4" by 1 foot by 3 feet piece of housing insulation as internal baffling. I was planning on replacing that with "acoustafil polyfil" or something similar. I was also considering putting back in the non-electric woofer as a type of baffle / air-flow since these boxes don't have anything else unless I cut something into the back (which I'm open to doing as I may re-do the cutouts for the connections to put in better connection (dare I say bi-amping!) plates. I was also hitting my head on going with a "four way" speaker setup instad of simply tweet/mid/woof/woof or tweet/mid/mid/woof config's. So I took consolatin that the mid/woof or woofer could go altogether and I would stick the passive woofer back in (or leve entirely open for baffle, but I haven't done those calc's yet).

So, is this a mess or what? I'm having a heck of a time coming up with a crossover configuration/setup that has any chance of turning these into something that one today's market would be worth $400 a piece (almost what I've spent on them in parts -- I got some other "goodies" justified by this project ? I'd appreciate any comments, suggestions, help. TIA,

Terry Parker
terryparker@myself.com

PS- If this gets too ugly, I would consider paypal-ing someone a consulting fee in order to "fix" this and/or help design appropriate crossover.

[owdi]

Your choice of drivers is, ... well... interesting. I wouldn't expect to see any of those together in a project except for the selenium woofer and tweeter. None of the speakers you selected can cover the 2.5-5khz octave, and none of them are great bass units.

If there is one solid recommendation I can make, it is to get rid of that tweeter. In home audio, heavy duty does not equal sound quality. Consider the Dayton RS28AS in it's place.

http://www.partsexpress.com/pe/showd...number=275-135

edit: To answer your question... yes, this is a mess. Maybe others with more experience can chime in, but the only reason why I've managed to design a good crossover is I selected drivers that work well together.

Dan

[angsuman]

Yea you're driver choice is very interesting too bad all your woofers are more or less 8in you're going to need a robust tweeter to mate with them. And you can't really use all those woofers in the same box. The davis woofers are expensive, maybe you could try to do a 2 way with a 28mm tweeter in a floorstanding configuration. If you don't have any measuring equipment try out passive crossover designer and have some fun. Maybe you could get away with something unorthodox.

[tlparker]

Originally posted by owdi
Your choice of drivers is, ... well... interesting. I wouldn't expect to see any of those together in a project except for the selenium woofer and tweeter. None of the speakers you selected can cover the 2.5-5khz octave, and none of them are great bass units.

If there is one solid recommendation I can make, it is to get rid of that tweeter. In home audio, heavy duty does not equal sound quality. Consider the Dayton RS28AS in it's place.

http://www.partsexpress.com/pe/showd...number=275-135

edit: To answer your question... yes, this is a mess. Maybe others with more experience can chime in, but the only reason why I've managed to design a good crossover is I selected drivers that work well together.

Dan

I ended up with the tweeter because it seemed like a good price for (remember, one that would fit) a ferro-fluid and it covers 2k-25k, so not sure how I missed the 2.5-5khz octave.
The selenium drive also goes 70 to 8khz, an even the dayton woofer goes to 2k (though I wouldn't count on it for that).

I agree with the remarks re bass, but I'm not looking for these speakers to cover that, I have sub's for that heavy-duty bass work, I certainly wouldn't expect to use these stand-alone without a powered sub. And remember, I want them to act as 7.1 surround rears (mono ambience), SACD / DVD audio rears (handle loud rock and lend support to the Paradigm's up front without distorting when I'm pushing everything to the limit). Right now I'm driving my Paradigm 100 fronts and center with one of those Monster 250wX3 they're giving away all over eBay (and I must say, I'm very pleased so far, and they're replacing a Carver mono-bloc'd PM series I had set up to drive the fronts for heavy rock). The sides and rears are still only being driven by the 120W channels coming from the Denon 3805.

Given all that, it still looks that bad, eh? I'll admit, this is a first for me, don't feel bad showing me where I'm screwing up, that's why I'm here .

[scudinc]

Try to return those Davis mids if you can�\they're way too expensive considering their performance and your needs. You could probably have new cabinets custom-made for you for as much as you spent on those things. The Selenium woofer and the tweeter are just inappropriate for this project. It would be best to let the cabinets go and try to start anew.

There's a nice project that uses the Dayton woofers in pre-built cabinets here. The crossovers may look hard at first glance, but the people here are good with that kind of thing and will help guide you through.

[tlparker]

Originally posted by scudinc
Try to return those Davis mids if you can�\they're way too expensive considering their performance and your needs. You could probably have new cabinets custom-made for you for as much as you spent on those things. The Selenium woofer and the tweeter are just inappropriate for this project. It would be best to let the cabinets go and try to start anew.

There's a nice project that uses the Dayton woofers in pre-built cabinets here. The crossovers may look hard at first glance, but the people here are good with that kind of thing and will help guide you through.

OK, here's a question for you then: Is there a way (using a scope/voltmeter/etc) that I could determine the characteristics of the old speakers and replace them with similar ones that would even work with the existing crossover, but would hopefully be of higher quality (and less age, these speakers have had some use)? This almost brings me back to what I was going to do originally: re-foam the woofers. But they just looked so cheaply made I really wanted to do something that would make me come out ahead of the game, not with just another set of Best-Buy Advents.

[tlparker]

Originally posted by scudinc
Try to return those Davis mids if you can�\they're way too expensive considering their performance and your needs. You could probably have new cabinets custom-made for you for as much as you spent on those things. The Selenium woofer and the tweeter are just inappropriate for this project. It would be best to let the cabinets go and try to start anew.

There's a nice project that uses the Dayton woofers in pre-built cabinets here. The crossovers may look hard at first glance, but the people here are good with that kind of thing and will help guide you through.

Also, can you explain WHY the Selenium woofer and the tweeter are innapropriate for this project? I'm trying to learn here as I go.

The Davis mid's were on sale, and these cabinets are definitely worth $500 (total what I paid for the mids) -- I have my own workshop and know what it would take to recreate them.

As for just "letting the cabinets go" I have two problems with that: It falls too much in line with our consumption society philosophy of It's Always Easier to Buy A New One Than Repair The Old One. I've found that this is RARELY true (it's almost never true with cars, and yet look how many new cars are sold to people each year). But secondly, I just can't believe that it should be that hard to take perfectly good cabinets and turn them into decent speakers, it just doesn't make sense. I mean, these speakers sounded pretty good before the woofers started going (nothing like my Paradigms, I'll admit, but then I'm not wanting to spend that much here either).

[PeteMcK]

Looking at the T/S parameters, the main probs seem to be:
the Selenium driver is really a guitar speaker & doesn't go low enough, so not suitable;

The Dayton woofers don't match the sensitivity of the Mid & Tweeter....but if you had another pair wired in parallel might be close to OK???

If you've already got the drivers, why not cobble together a really simple xover and give them a try?

[owdi]

Here is a link to the measured frequency response of the tweeter...

http://www.partsexpress.com/pdf/270-145g.pdf

As you can see it's useless below 6khz. This is a high efficiency noise maker used to add some sparkle for pro sound applications (clubs, small concerts). Completely inappropriate for home audio use. The cheapie $5 dayton tweeters will outperform this tweeter in your living room at normal listening levels.

Here's a link to the measured response of the Dayton woofers

http://www.partsexpress.com/pdf/295-366g.pdf

The HF breakup means you will need a complicated crossover if you want to cross over higher than 1khz.

Dan

[tlparker]

Originally posted by owdi
Here is a link to the measured frequency response of the tweeter...

http://www.partsexpress.com/pdf/270-145g.pdf

As you can see it's useless below 6khz. This is a high efficiency noise maker used to add some sparkle for pro sound applications (clubs, small concerts). Completely inappropriate for home audio use. The cheapie $5 dayton tweeters will outperform this tweeter in your living room at normal listening levels.

Here's a link to the measured response of the Dayton woofers

http://www.partsexpress.com/pdf/295-366g.pdf

The HF breakup means you will need a complicated crossover if you want to cross over higher than 1khz.

Dan

Thanks a bunch. Looking at the CLIO data graphs on the tweeter makes the picture a lot clearer than just reading the product descriptions (freq. resp: 2k-25khz, or some such). I definitely see how I need to take into consideration fr at different levels.

I'm wondering if I should just use the old tweeters (which seemed to work fine), throw in the Davis mid's and the mid/low woofer and see what happens. I think I might get pretty much what I'm looking for. Now back to one of the big Q's (which I see so often around here): How to design crossover? Would Winspeakerz be any good for this type of thing?