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Discussion Starter · #1 ·
I have a chance to acquire the drivers and crossovers for a pair of Joseph Audio RM7si bookshelf speakers. However I have no cabinets in which to install everything.


Can anyone suggest either a way to find a pair of cabinets, or some alternative high quality cabinets that match the size and features of the RM7's? Maybe I can find someone that has some gutted cabinets or non-functioning units they wish to part with?


A few google/ebay searches taught me that it is difficult to locate a variety of broken speakers for sale
Other google searches taught me that buying pre-built empty cabs is expensive.


How would you solve this problem?
I simply cannot pass up this opportunity!!


15"H x 9"W x 12"D

Weight: 27 lbs each


1" Tweeter on top

6.5" Woofer in the middle

Port on the bottom


For reference:
http://www.stereophile.com/content/j...specifications
 

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Discussion Starter · #3 ·
Instead of buying the Madisounds would there be any benefit in sound quality to purchasing a better engineered cabinet? I'm thinking of this:

http://www.polkaudio.com/homeaudio/r...ex.php?s=rtia1


I'm thinking this cabinet might be superior to the Madisounds because it has the following features:


- 6 layers of MDF with dampening layers in between.

- Curved cabinet to reduce internal resonance

- Should come pre-braced and with dampening fill already inside the box

- Has a neat Porting method (you can read about it on the web page)

- Comes with a flared port, so we don't have to make one


Although the dimensions are a bit off.


(in inches)

RM7si = 15 x 9 x 12

Rti A1 = 12 x 7.5 x 11.5"


If the Rti A1 needs to be bigger then we might consider the Rti A3:


Rti A3 = 14.75 x 8.5 x 14


Thoughts?
 

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Unless you're getting those RTI-A3s for dirt cheap I dont really see any advantage to going that route.


You can buy dowel rods, a hand saw, and some PL Premium adhesive to add more bracing to that madisound box if you feel it's necessary. Cabinet foam is cheap, a can of spray adhesive is all you need to adhere it. You need to match the port diameter and length of the RM7s if you want your speakers to sound the same. The link you posted has it at 1.75" x 3", here's a 1.75" x 4" , just cut an inch off.
 

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Discussion Starter · #6 ·
Hi Irwin, I'd love to know myself
I'm meeting my friend who has graciously offered me the parts this weekend. I'll find out and update!! :-D I'm hoping for the aluminums.
 

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Quote:
Originally Posted by hernejj /forum/post/20882912


15"H x 9"W x 12"D

Weight: 27 lbs each


1" Tweeter on top

6.5" Woofer in the middle

Port on the bottom

Those Joseph Audio speakers are good bookshelf speakers. To get the most from those speaker parts, a new cabinet must reproduce these features of the old cabinets:
  • Internal volume
  • Port inner diameter and length
  • Front baffle dimensions - especially the width
  • Locations of the woofer & tweeter on the front baffle

These are essential features. The original cabinet volume and port dimensions were designed for that particular woofer, and the crossover was designed for that front baffle width and those driver locations. If you substitute a cabinet that differs from these (such as that Polk cabinet), all bets are off.


Those dimensions you gave, 15"H x 9"W x 12"D, are they external or internal? If they are external, you can estimate the internal dimensions if you know how thick the old speaker cabinet walls are.


Where is the old cabinet? Is it available to at least get the internal dimensions, port dimensions, and driver locations?
 

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Discussion Starter · #8 ·
R Swerdlow,

Thanks. Given all those factors, and the fact that I'd like these to sound as close to real RM7's as possible I think I'm going to make the cabinets myself. I know a wood worker who can route the front baffle for flush mounting the drivers.


The dimensions given are external. The old cabs are unfortunately NOT available. I'm not sure what became of them. I'll have to scrounge around for more info on the cabs so I can accurately reproduce them.
 

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Quote:
Originally Posted by hernejj
R Swerdlow,

Thanks. Given all those factors, and the fact that I'd like these to sound as close to real RM7's as possible I think I'm going to make the cabinets myself. I know a wood worker who can route the front baffle for flush mounting the drivers.


The dimensions given are external. The old cabs are unfortunately NOT available. I'm not sure what became of them. I'll have to scrounge around for more info on the cabs so I can accurately reproduce them.
You do know for certain that the front of the cabinet should be 15" high × 9" wide external. You can guesstimate the locations of the drivers from the photos and be reasonably close. If you use ¾" MDF to build new cabinets, that would be 13½" × 7½" internal. All you really need to know is how deep to make the inside of the cabinet and the diameter & length of the port tube.
  • Tell Joseph Audio your situation and ask them for guidance. The worst they can do is say no, but they might help you considering this model is no longer sold.

  • Is you woofer yellow fiberglass or aluminum? The aluminum one looks very much like the L18RNX/P woofer made by SEAS, a Norwegian manufacturer. Madisound sells SEAS drivers in the US. Contact them and ask if they can suggest answers about tuning the bass, i.e. the cabinet depth and port dimensions.


Good luck!
 
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