Refoam AR-9 woofer

[Mez]

Well, I re-foamed my AR9 12" woofers last weekend.  This is the AR-9s I bought from the original owner that included the shipping boxes and manuals delivered in the boxes.  I already replaced the caps on the upper frequency cross overs so I started playing them. I felt some of the bass response was not as low or loud as it should be and after moving them around in my living room, it really didn't improve.

The woofers were re-foamed before I bought them 2 months ago and looked fine but after doing the research here, I concluded the wrong foam surrounds were used.  They were the stiffer, narrower roll and they were cut and spliced together to make them fit.  They were neatly glued, so whoever did them took there time.

I felt there was something wrong with bass response.  The bass didn't seem to go as deep and lacked that "punch" I hear with my set of New Large Advents.

I bought the bigger roll surrounds from a company in Canada off of eBay.  They fit much better and had the angle at the edge on the paper cone side.

After all done, one of the voice coils rubbed. Crap!!!  During the first try, I used small blocks of foam to prop up the paper cone so I could glue the new surround but apparently it pulled it to one side and cocked the voice coil.  So I removed the dust cap over the voice coil, shimmed the coil with plastic strips to get it re-centered, and carefully cut the glue between the new surround and the metal frame to re-position it before re-glued the surround to the frame again.  I re-glued the voice coil dust cap and tested it.  No rubbing. Hurray!  By the way, removing and reinstalling the voice coil dust cap was super easy.

I re-installed the woofer and played some heavy bass tracks (Metallica) and noticed the bass response was deeper and that "punch" was there.  Much improved.

So, what I learned from this forum was to use the correct foam surrounds and to shim the voice coil.  I thank you all.

[fedeleluigi]

On 11/14/2018 at 11:04 PM, Mez said:

carefully cut the glue between the new surround and the metal frame to re-position it before re-glued the surround to the frame again.  I

Mez,

That's Ok if the woofer is the replacement part manufactured by Tonegen ( part# 1210003-XX). If the woofer is the original AR woofer (part # 200003),  the outer edge of the foam is normally glued to a masonite ring that is glued to the metal frame. If someone erroneously removed the masonite ring you should restore it.

Luigi

 

[Mez]

Mine do not have the Masonite rings.  Damn it....

[Mez]

I am not sure I will replace the Masonite rings. 

First, I'd have to buy new surrounds to replaced the ones I just installed. 

Second, I'd have to cut the rings from Masonite.e

Third, they sound really good now.  I cranked them way up yesterday, and didn't hear anything wrong and the bass was outstanding. 

So not sure what I'd gain by adding the Masonite rings other than appearance.

[Stimpy]

The Masonite rings would give the woofers a bit more travel.  The thickness of the Masonite would determine this.  But, if the woofers aren't bottoming out or distorting, I'd be willing to leave things as is too.

 

[frankmarsi]

You may have to buy replacements.

I just checked my 9's and the masonite looks a slight bit thinner than the original classic woofer line.

 

 

[ra.ra]

3 hours ago, Stimpy said:

The Masonite rings would give the woofers a bit more travel.  The thickness of the Masonite would determine this.  But, if the woofers aren't bottoming out or distorting, I'd be willing to leave things as is too.

I think Stimpy may be offering very good advice here. The part drawing for the 12-inch 003 woofer clearly shows the masonite ring at both surround and spider locations, and this is nothing more than typical 1/8" nominal thickness hardboard. The cone excursion may be somewhat limited without the ring, but I suspect that limitation would only show up at high volume levels when the woofer is pushing some really big air. 

6 hours ago, Mez said:

Third, they sound really good now.  I cranked them way up yesterday, and .... the bass was outstanding. 

 If the performance is this satisfying with your typical program material, there's probably no need for further corrective measures.  

[Mez]

If the woofers didn't bottom out playing Metallica at very high volume, they should be good on anything!!

[Aadams]

4 hours ago, Mez said:

If the woofers didn't bottom out playing Metallica at very high volume, they should be good on anything!!

IMO your choice of Metallica is fortuitous.  The dynamic range is sufficiently narrow that the speakers can play very loud in a 3000 cft room, for example, without having to negotiate any threatening dynamic peaks.  Also, the underlying bass in most metal rock doesn’t go as deep as it subjectively sounds so the woofer excursion remains in a safer range by not being fed longer wavelengths.

Adams

[Mez]

18 hours ago, Aadams said:

IMO your choice of Metallica is fortuitous.  The dynamic range is sufficiently narrow that the speakers can play very loud in a 3000 cft room, for example, without having to negotiate any threatening dynamic peaks.  Also, the underlying bass in most metal rock doesn’t go as deep as it subjectively sounds so the woofer excursion remains in a safer range by not being fed longer wavelengths.

 

Adams

True. I don't use this system for home theater, so it doesn't see those sub-20hz signals from crashes and the like.