Philips Tweeters / NAS refurb

[panterra]

I bought some North American Sound Monitor Series Speakers in 1984.

Here is the brochure for reference:
<A HREF="http://tinyurl.com/33aykt">http://tinyurl.com/33aykt</A>
<A HREF="http://tinyurl.com/2pfkbp">http://tinyurl.com/2pfkbp</A>
<A HREF="http://tinyurl.com/3yd4dw">http://tinyurl.com/3yd4dw</A>

Here is a crossesction of the ~2.5 ft^3 "bass reflex" cabinet:
<A HREF="http://tinyurl.com/39fcn4">http://tinyurl.com/39fcn4</A>

What kind of cross-over is this, note the precision soldering ;-). Brochure says the crossover is at 3500 hz.
<A HREF="http://tinyurl.com/2lnk3t">http://tinyurl.com/2lnk3t</A>

These are the tweeters
<A HREF="http://tinyurl.com/2ag6yv">http://tinyurl.com/2ag6yv</A>
<A HREF="http://tinyurl.com/2z7g8f">http://tinyurl.com/2z7g8f</A>
I have 4 extras that I could use in another project. I'm such a noob though.

I have had the woofers foam surround reglued a couple of times over the years, and a chip from the ceramic magnet of one of the woofer has been finding its way in the gap every once in a while, so I was thinking of replacing the woofers and xo, so I essentially have cabinets with nice tweeters. Is it as simple as getting an appropriate off the shelf xo from PE and some 8" woofers that match as closely the 92 db sensitivity listed on the speaker brochure? Any ideas would be greatly appreciated.

Steve

[dthomas]

Provided Link: http://www.partsexpress.com/pe/showdetl.cfm?&amp;Partnumber=296-175


> I bought some North American Sound Monitor
> Series Speakers in 1984.

> Here is the brochure for reference:
> <A HREF="http://tinyurl.com/33aykt">http://tinyurl.com/33aykt</A>
> <A HREF="http://tinyurl.com/2pfkbp">http://tinyurl.com/2pfkbp</A>
> <A HREF="http://tinyurl.com/3yd4dw">http://tinyurl.com/3yd4dw</A> Here is a
> crossesction of the ~2.5 ft^3 "bass
> reflex" cabinet:
> <A HREF="http://tinyurl.com/39fcn4">http://tinyurl.com/39fcn4</A> What kind of
> cross-over is this, note the precision
> soldering ;-). Brochure says the crossover
> is at 3500 hz.
> <A HREF="http://tinyurl.com/2lnk3t">http://tinyurl.com/2lnk3t</A> These are the
> tweeters
> <A HREF="http://tinyurl.com/2ag6yv">http://tinyurl.com/2ag6yv</A>
> <A HREF="http://tinyurl.com/2z7g8f">http://tinyurl.com/2z7g8f</A> I have 4 extras
> that I could use in another project. I'm
> such a noob though.

> I have had the woofers foam surround reglued
> a couple of times over the years, and a chip
> from the ceramic magnet of one of the woofer
> has been finding its way in the gap every
> once in a while, so I was thinking of
> replacing the woofers and xo, so I
> essentially have cabinets with nice
> tweeters. Is it as simple as getting an
> appropriate off the shelf xo from PE and
> some 8" woofers that match as closely
> the 92 db sensitivity listed on the speaker
> brochure? Any ideas would be greatly
> appreciated.

> Steve

The crossover is a first order on the tweeter. There is no crossover on the woofer as it is being ran full range.

It is not very likely an off the shelf crossover will provide much benefit... they rarely do.

You could try to find a woofer that plays fairly smooth up to 3KHz and try dropping it in as a replacement. But that would still be a guess without having some measurement data on the tweeter and existing woofer.

This woofer might work as an easy fix but no promises. You would need to add a series resistor to the tweeter to pad it down just a bit. But this is really just a guess. Without knowing what the response of the original drivers looks like it is really hard to say and any advice is just going to be a best guess.

Or you could start over and replace both drivers or get someone to measure your tweeter and mate a good 8" driver with it. Very difficult to find any 8" drivers that will play up to 3.5KHz.

Dave

[johnastockman]

> I bought some North American Sound Monitor
> Series Speakers in 1984.

> Here is the brochure for reference:
> <A HREF="http://tinyurl.com/33aykt">http://tinyurl.com/33aykt</A>
> <A HREF="http://tinyurl.com/2pfkbp">http://tinyurl.com/2pfkbp</A>
> <A HREF="http://tinyurl.com/3yd4dw">http://tinyurl.com/3yd4dw</A> Here is a
> crossesction of the ~2.5 ft^3 "bass
> reflex" cabinet:
> <A HREF="http://tinyurl.com/39fcn4">http://tinyurl.com/39fcn4</A> What kind of
> cross-over is this, note the precision
> soldering ;-). Brochure says the crossover
> is at 3500 hz.
> <A HREF="http://tinyurl.com/2lnk3t">http://tinyurl.com/2lnk3t</A> These are the
> tweeters
> <A HREF="http://tinyurl.com/2ag6yv">http://tinyurl.com/2ag6yv</A>
> <A HREF="http://tinyurl.com/2z7g8f">http://tinyurl.com/2z7g8f</A> I have 4 extras
> that I could use in another project. I'm
> such a noob though.

> I have had the woofers foam surround reglued
> a couple of times over the years, and a chip
> from the ceramic magnet of one of the woofer
> has been finding its way in the gap every
> once in a while, so I was thinking of
> replacing the woofers and xo, so I
> essentially have cabinets with nice
> tweeters. Is it as simple as getting an
> appropriate off the shelf xo from PE and
> some 8" woofers that match as closely
> the 92 db sensitivity listed on the speaker
> brochure? Any ideas would be greatly
> appreciated.

> Steve

Steve, I added my penny's worth to your other post below, but AFA using an off-the-shelf XO, Dave's right...rarely do they give even adequate results. Usually, not so good. There are a couple projects that use an 8" in a 2-way design. One is the Noah 8's in the Project Showcase and another is found at the link. I'm not sure if they would work with your box size, but it could be worth a look.

<A HREF="http://www.wadsnet.com/~dtenney/dayton_8MT.htm">http://www.wadsnet.com/~dtenney/dayton_8MT.htm</A>

John A.

[panterra]

> Steve, I added my penny's worth to your
> other post below, but AFA using an
> off-the-shelf XO, Dave's right...rarely do
> they give even adequate results. Usually,
> not so good. There are a couple projects
> that use an 8" in a 2-way design. One
> is the Noah 8's in the Project Showcase and
> another is found at the link. I'm not sure
> if they would work with your box size, but
> it could be worth a look.

>
> <A HREF="http://www.wadsnet.com/~dtenney/dayton_8MT.htm">http://www.wadsnet.com/~dtenney/dayton_8MT.htm</A>
> John A.

Thanks John, I appreciated both of your comments. I realized my other post was so buried in the thread list and it was going to get off topic, I posted this on. it looks like my cabinet is the right size for the ported option from the above link. This could be an interesting project.

[porper]

n/a

[panterra]

You know, that is what the brochure said, as well.