# Replace drivers or start from scratch?



## LMN8R (May 19, 2009)

I've ordered new drivers for my mains. I had a set (actually two pairs) of Genesis Physics speakers in the early 80's that I absolutely loved. The company went out of business twenty years ago but one of the partners is still selling replacement drivers (also for EPI) and complete speakers under the Human Speaker brand. I'm planing to replace the drivers in my Yamaha 6490 cabinets with the K81 kit but have a concern. The cabinet size is OK at 1 cubic foot. The cutouts will work for the 8" woofer and the tweeters will mount where the current mid-range speakers are mounted. I plan to put a block off plate over the hole for the existing tweeter. My concern is the cabinet is only 1/2 inch material (I assume MDF). The finish is nice and I can use the existing grills. Is the 1/2" worth a try or should I plan to just build new?
Any thoughts would be appreciated.


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## Jstslamd (Nov 30, 2010)

Do you have a link for the k81 kits ? I would venture to say you could build a much more suitable cabinet with a fresh start than rigging an old cabinet to suit the needs for the kit you are looking at. By building a new cabinet you can make it more rigid with bracing and add some dampening material to get every bit of smooth sound out of your drivers. Just my 2cents.


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## LMN8R (May 19, 2009)

http://http://www.humanspeakers.com/diy/81.htm
This is what I have ordered.


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## bambino (Feb 21, 2010)

Personally i would start from scratch but that is just the DIY guy in me talking. If your capable then that is the route i would take.:T


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## fbov (Aug 28, 2008)

To me, the beauty of DIY is DWYW - do what you want. There are real disadvantages to re-using a box, primarily in the fact that driver location on the baffle, and baffle dimensions, are inputs to speaker design - they affect the sound. Therefore, your implementation of the K81 kit will not sound like the Yammys, nor will it sound like a Human 81. 

Try it, if you're disappointed, build a new box to Human 81 specs. 

If you do try it, a little bracing will go a long way toward a successful outcome. Hardwood dowel rods are all you need, connecting centers of the large panels... and one front to back bracing the "point between the woofer and tweeter cutouts." There should be pleny of access once the woofer's out.

Have fun,
Frank


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## robbo266317 (Sep 22, 2008)

The other consideration is whether the crossover is suited to the newer drivers along with the fact that after 30 odd years the capacitors may have dried out and may need replacing.


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## LMN8R (May 19, 2009)

robbo266317 said:


> The other consideration is whether the crossover is suited to the newer drivers along with the fact that after 30 odd years the capacitors may have dried out and may need replacing.


The kit comes with new crossovers. I'm leaning toward trying the drivers in my existing boxes, bracing if necessary and building new if I'm disappointed. The existing boxes look nice and would be tough for me to improve on cosmetically.


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## robbo266317 (Sep 22, 2008)

LMN8R said:


> The kit comes with new crossovers. I'm leaning toward trying the drivers in my existing boxes, bracing if necessary and building new if I'm disappointed. The existing boxes look nice and would be tough for me to improve on cosmetically.


Let us know how they turn out. :T


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## JimH (Nov 11, 2011)

I did a similar thing a year ago. Had a set of older speakers where the boxes that were close to what was needed for the Dayton BR-1 design. Had to modify the baffle but the improvement in sound was signficant. They are now my basement shop speakers. I say go for it.


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## LMN8R (May 19, 2009)

Made a couple of stops on my way home from work and picked up 1" oak dowel rod, Titebond II, foam weather strip and a couple of small polyfill pillows. Drivers are supposed to be delivered on Friday. I plan to modify the enclosures tomorrow night and have them ready for assembly on Friday. I work four tens and have Fridays off. I'll post pictures as progress is made. Thanks to all for the help and advice. I think this is going to be a huge improvement especially for two channel music, I have a 7.3 system. If they are even close to my old Genesis speakers I'll be thrilled. My wife has out of town meetings next week and will be gone Mon-Wed which means I'll get to really try them out in the evenings.


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## LMN8R (May 19, 2009)

I have a quick question on retrofitting braces. Do you radius opposite sides of the ends of the dowel to facilitate installation. It seems they would be impossible to install without it. If so, how much is required?


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## LMN8R (May 19, 2009)

Thought I would update everyone on where I'm at and post a couple of pictures.
First a picture of my living room setup







A before picture of one of the speakers I'm updating







A picture of the speaker with the driver removed and braces added







I ended up cutting the braces 1 1/2 inches short, cut them in half, "rifled" them by drilling a hole 3" deep from one end using 7 1/2 " all thread, washers, nuts and red loctite to keep them from loosening. Glued the ends tightened the nuts to expand the brace seating it into the cabinet. One brace between the woofer and tweeter front to back and one that will be behind the woofer connecting the two largest panels (the sides).
The drivers and crossovers are in OKC and scheduled to be delivered (UPS) tomorrow.


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## LMN8R (May 19, 2009)

Before anyone asks why such large speaker stands......


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## robbo266317 (Sep 22, 2008)

Looking good, I had wondered about the plinths. Nicely done.


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## LMN8R (May 19, 2009)

They hold 200 blu rays each and are the DIY project I'm most proud of. I love my subs (2 DIY ported CSS SD 12's and a Crown 802 for power) but I made the mistake of hooking them up before getting a finish on them and now I don't want to be without them long enough to get them laminated, stained and varnished. lol


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## ALMFamily (Oct 19, 2011)

Nicely done on the stands - they look great! :TT


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## LMN8R (May 19, 2009)

Driver/Crossover swap is complete.







First impressions: First I turned down my subs about 5 db, the increased bottom end of the "new" speakers is very impressive. The midrange and trebble is just more full and pleasent to listen to. So far I've just listened to the Boston debut album (actually CD) in 2 channel and am very pleased. Time for some MC music now.
Thanks to all for the advice.

Edit: I left the original tweeters in since they were sealed in the back until I figure out a better way to seal the hole.


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## robbo266317 (Sep 22, 2008)

I'm glad they turned out to your liking. 
Does your amp have audyssey, or similar, and if so have you run it yet?


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## LMN8R (May 19, 2009)

It's a Yamaha AVR with YPAO. I haven't run it yet, I'm waiting for a quiet house. Probably later tonight. Enjoying the Eagles Farewell Tour right now. So far everything I've listened to (CD, SACD, BR, DVD has had me grinning ear to ear. I feel like a kid on Christmas morning. I'm floored by how much better it sounds. I think it's the best $300 I've put into my system.


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## LMN8R (May 19, 2009)

I've now ran YPAO. It set the fronts to large for the first time but I changed them back to small. I had almost forgotten how good these tweeters really are. So clean and easy on the ears. I'm one happy camper.


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## robbo266317 (Sep 22, 2008)

You are lucky being able to set the fronts to large. 
Mine keeps setting them to small, yet REW begs to differ....


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## LMN8R (May 19, 2009)

I'd been trying to make up for the lack of mid-bass by cranking up the subs a few db and raising my crossover setting in the AVR to 110hz. I no longer need to do that (although I still run the subs a little hot). I'd been tempted to put a couple of small subs under my mains or add a mid-bass module near field. This speaker mod has taken care of that urge as well. The new 8" drivers have 9mm x-max and better sensitivity and it did the trick.


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## Seaxe (Sep 13, 2008)

LMN8R, good post on repurposing "monkey coffins' .A few years back I did the same (after much reading and calculations), and now have the best speakers I have owned. I still use a separate 12' woofer system for mid bass/ bass extension. Am listening to Pink Floyd as I post. Wonderful. Cheers, Mike.


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## fbov (Aug 28, 2008)

Glad to hear things went well!


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