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Realistic Nova 8b Rebuild & Crossover Re-Design

Nova 8bs after Mods

Smorgy said:
I think I will build one pair of crossovers and put 1 in an Optimus 5b and 1 in a Nova 8b (with the modded tweeter). Then I can mix and match. When I'm done playing, I can decide where to go from there.

I am still curious as to what speakers you would compare these to once they have the new crossovers installed....

//Smorgy
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It is a hard question as they are so different than most out there. The closest thing that comes to mind is the NAMM DBL speakers.
 
Hate to push my luck, but any plans for other RS speakers? You've got an awesome thread on the Mach One's, this thread on the Nova 8b's, anything next?

Curious minds want to know. ;-)
 
Speaker Plans

Copa1934 said:
Hate to push my luck, but any plans for other RS speakers? You've got an awesome thread on the Mach One's, this thread on the Nova 8b's, anything next?

Curious minds want to know. ;-)
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I plan on doing the Nova 7bs after I finish the Mach One thread. I don't have any other RS speakers but I am open to talking about others.
 
tiga said:
Just curious - is there much of a cross-over in the T-200? I ask because in the T-100 there is only a cap and a variable resisitor. Sorry to get off topic.
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The T-200 speakers were the Shacks flagship speakers around 1980, typically paired up with their STA 2100 receiver. They are a sealed cabinet with 2 10" bass (16 ohm), a 6" midrange (8 ohm), and a 2" tweeter (8 ohm).

Not much of a crossover in these either. A 33uf cap and a 3.3uf cap with a variable resistor for mid and tweeter (1-5 Kh and 5Kh & up).

Tweeters are pretty much unobtainium now. When I got mine 6 years ago, I went in to get replacement woofers and they sold me 8 ohm woofers which they swore were the correct replacement woofers for the T-200. :no:

In spite of all of that, they sound ok, although I had to wire the woofer in series instead of parallel. I used a pair of tweeters from Baby Advent speakers, but they are not really so good for this application. They sound much better when I use the Microstatic super tweeters along with them.

Couple of photos included. The cabinets are really nice.

//Smorgy
 

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If the woofers they sold weren't "air suspension" chances are they're not a good "fit" for this application. Unfortunately I've had trouble finding technical information about choosing woofers for applications like this or paired with a passive radiator. Finding appropriate woofers would be infinitely easier if this information were readily available. Maybe an AK reader knows of such links or info?
 
Copa1934 said:
If the woofers they sold weren't "air suspension" chances are they're not a good "fit" for this application. Unfortunately I've had trouble finding technical information about choosing woofers for applications like this or paired with a passive radiator. Finding appropriate woofers would be infinitely easier if this information were readily available. Maybe an AK reader knows of such links or info?
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The problem with the woofers that they sold me was that they are 8 ohm woofers. Since there are 2 connected in parallel, the result is only 4 ohms, not the correct 8 ohms that would result from a pair of 16 ohm woofers like the originals.

//Smorgy
 
Copa1934 said:
If the woofers they sold weren't "air suspension" chances are they're not a good "fit" for this application. Unfortunately I've had trouble finding technical information about choosing woofers for applications like this or paired with a passive radiator. Finding appropriate woofers would be infinitely easier if this information were readily available. Maybe an AK reader knows of such links or info?
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Low Q woofers tend to be good for ported enclosures which means they also tend to good for passive radiators. Medium Q (qts in the .4-.6 range) tend to make good sealed box woofers.
 
I would suggest starting a new thread since this is starting to get a little long winded, not a bad thing, just be nice to have a dedicated thread instead.

Wondering if it's possible to use a resistor in conjunction with this, either in a parallel or serial fashion, but I'm not an expert on this. Regardless, even if you do get the impeadance correct, you may still not be satisfied if the woofers are the wrong "type" of woofer, as I mentioned earlier. I would confirm that info first. If you don't know or don't have the packing anymore, no problem. The model number should be on the woofer. On the RS site there is a link that has specs on the raw speakers they've sold over the years. Not all, but a good selection of them. Your's might be in there. That would be a good place to start. I believe this is the correct link to use http://support.radioshack.com/support_audio/17320.htm check out "Speaker Components" down a ways or do a find "ctrl + f" using the model/catalog number.
 
Cool. Are there any formulas to help with cabinet/crossover calculations? Most I see deal with single woofers using either sealed or ported enclosures and not dual woofers or woofer/passive combos? Also wondering about individual chambers for dual woofers or do they share the same space?

Thanks!
 
If you have microsoft excel, a search on google for "Unibox" will lead you to a very nice program loaded with options.
 
Mods Status??

Has anyone completed the crossover rebuild on their Nova 8bs or Optimus 5bs yet?? Been doing a lot of listening!! These are so good! If you haven't changed yours yet you are missing alot! I was just wondering and am looking for feedback from anyone that has completed theirs! :yes:
 
videolady201 said:
Has anyone completed the crossover rebuild on their Nova 8bs or Optimus 5bs yet?? Been doing a lot of listening!! These are so good! If you haven't changed yours yet you are missing alot! I was just wondering and am looking for feedback from anyone that has completed theirs! :yes:
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I don't own either one of these speakers yet. But I am looking for them specifically because of your work in this thread.
 
videolady201 said:
Has anyone completed the crossover rebuild on their Nova 8bs or Optimus 5bs yet?? Been doing a lot of listening!! These are so good! If you haven't changed yours yet you are missing alot! I was just wondering and am looking for feedback from anyone that has completed theirs! :yes:
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Parts are ordered, just waiting on them to arrive. I'll post feedback when complete.

//Smorgy
 
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