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12" passive radiator replacement?



 
 
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  #31  
Old January 11th 20, 07:55 PM posted to rec.audio.pro
nickbatz
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Default 12" passive radiator replacement?

> Surely you wouldn't have a PC that *hasn't* some sort of audio interface
> on the mainboard, at least ?!!
>
> geoff



Well, when I said "any of" my Windows machines, that really meant the new on - only 2009. The others are all Pentium 4s I haven't turned on in years.

But it does have system audio going out via Microsoft Remote Desktop to the Mac I access it from.

And I do have more than one class-compliant USB audio interface lying around, so maybe I'm guilty of hyperbole.
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  #32  
Old January 14th 20, 01:14 AM posted to rec.audio.pro
nickbatz
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Default 12" passive radiator replacement?

EGG ON FACE.

After removing the crumbled foam, it turns out that these aren't passive radiators at all, they're 12" rear-firing woofers!

So these are sealed tower boxes with 3-way speakers on the front - including what looks like a soft-dome tweeter with a plastic cage on it that I'll have to look at more closely to see whether it wants removing (i.e. I'll have to see whether it's just for protection, as opposed to being some kind of wave guide).

The cones are moving freely, which is enouraging.

Sorry for the false passive radiator alarm. Will pick up a couple of surrounds from ebay and make these things work.
  #33  
Old January 14th 20, 05:25 PM posted to rec.audio.pro
Scott Dorsey
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Default 12" passive radiator replacement?

nickbatz > wrote:
>EGG ON FACE.
>
>After removing the crumbled foam, it turns out that these aren't passive ra=
>diators at all, they're 12" rear-firing woofers!


No problem, then, much easier to deal with. Just refoam them.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #34  
Old January 15th 20, 12:05 AM posted to rec.audio.pro
nickbatz
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Default 12" passive radiator replacement?

> No problem, then, much easier to deal with. Just refoam them.
> --scott


Yup. Already ordered the surrounds.

RSL made hundreds of similar speakers, and the reason I assumed it was passive is that I found a brochure for a model that looked just like this one that did have a passive radiator.

These look like they were meant to be good living room speakers, probably not audiophile-level but on the higher end of RSL's lines.
  #35  
Old January 22nd 20, 08:33 PM posted to rec.audio.pro
nickbatz
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Posts: 152
Default 12" passive radiator replacement?

Since the world is waiting with bated breath - update: I fixed them.

Not bad. Haven't connected them to my good power amp (Hafler 9505), but the biggest problem is almost no useful response below 50Hz - despite having two 12" woofers each.

My first thought was that the front- and rear-firing woofers aren't in phase, but nope.

Probably not keepers, but I'm only 90% sure.
  #36  
Old January 23rd 20, 06:01 AM posted to rec.audio.pro
Trevor
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Default 12" passive radiator replacement?

On 23/01/2020 7:33 am, nickbatz wrote:
> Since the world is waiting with bated breath - update: I fixed them.
>
> Not bad. Haven't connected them to my good power amp (Hafler 9505), but the biggest problem is almost no useful response below 50Hz - despite having two 12" woofers each.
>


Pretty normal when the T/S parameters aren't suitable for a small box.
You often get higher efficiency than a smaller driver, but not
necessarily lower bass.
  #37  
Old January 23rd 20, 06:30 PM posted to rec.audio.pro
nickbatz
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Posts: 152
Default 12" passive radiator replacement?

> Pretty normal when the T/S parameters aren't suitable for a small box.
> You often get higher efficiency than a smaller driver, but not
> necessarily lower bass.


I know everything.

That is, except for what T/S paramaters are.
  #38  
Old January 24th 20, 01:42 PM posted to rec.audio.pro
Scott Dorsey
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Default 12" passive radiator replacement?

nickbatz > wrote:
>Since the world is waiting with bated breath - update: I fixed them.
>
>Not bad. Haven't connected them to my good power amp (Hafler 9505), but the biggest problem is almost no useful response below 50Hz - despite having two 12" woofers each.
>
>My first thought was that the front- and rear-firing woofers aren't in phase, but nope.


If the slope of the rolloff is very sharp (sharper than 6dB/octave), they
likely were designed to have been used with a subwoofer. They are from that
era where the sat/sub thing was becoming very popular.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #39  
Old January 24th 20, 06:32 PM posted to rec.audio.pro
nickbatz
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Posts: 152
Default 12" passive radiator replacement?

If the slope of the rolloff is very sharp (sharper than 6dB/octave), they
> likely were designed to have been used with a subwoofer. They are from that
> era where the sat/sub thing was becoming very popular.
> --scott



Could be, and the rolloff is pretty steep. There actually is some useful response at 40, but between 60 and 30 there's more than a 6dB cut.

But these are tower speakers, and the RSL brochure I found online with similar-looking speakers (except passive radiators, hence my original assumption) didn't have a sub in it.

I'd expect there to be a crossover to the sub built in, even though these are passive xovers. Still, whether or not that was the design, Ima try hooking up my Blue Sky sub just for fun.

By the way, Manny LaCarubba (Sausalito Audioworks), who's as good a speaker designer as there is, uses subs in his systems. The twist is that he uses multiple ones, not just a single one. So it's not just that era!
  #40  
Old January 25th 20, 03:30 PM posted to rec.audio.pro
Ty Ford[_2_]
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Posts: 77
Default 12" passive radiator replacement?

On Wednesday, January 22, 2020 at 3:33:08 PM UTC-5, nickbatz wrote:
> My first thought was that the front- and rear-firing woofers aren't in phase, but nope.
>
> Probably not keepers, but I'm only 90% sure.


Shouldn't the front and rear be out of phase?
 




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