The ultimate AR 11 inch woofer? - if you can afford it

[Carlspeak]

Madisound has recently introduced a Scanspeak 11" woofer with spec's I think match up well with the original AR3 and 3a woofers. Not sure about a drop in fit, but everything else looks good to me - one whose tested many vintage 11" AR woofers over the years. 4 ohm, low Qts, DCR of 3 ohms. The FR looks like the 500 hz xover point will work. Power handling is also excellent. 200 watts RMS.

Now for the bad news. It's priced at over $500. Oh, and that's each.

https://www.madisoundspeakerstore.com/approx-11-woofers/scan-speak-28w/4878t-revelator-11-subwoofer/

 

[frankmarsi]

I gotta see this!

Wait here, I'll be right back.

FM

Okay, it looks the part but,  can it dance the mambo? Can it do the 'tarantella'  or the 'chicken', or the 'twist' (like we did last summer), or the 'jerk',  how about the 'nerd's special'; the 'just stand there' while maybe putting out a toe or two, here and there, while swinging out an elbow now and then?

Other than that, the free-air resonance could be a hair lower. I do like the 3 inch VC though.

I don't get the "Titanium former and paper reinforced", how much of that former is titanium?

Scan-Speak much like Dynaudio is always a little over priced, no?

Okay, who is going to see first and start cutting that frame so it'll fit the AR cut-out?

[DavidR]

Looks like a beast.

I guess if you need it you need it.

[tysontom]

On 8/2/2017 at 5:46 PM, Carlspeak said:

Madisound has recently introduced a Scanspeak 11" woofer with spec's I think match up well with the original AR3 and 3a woofers. Not sure about a drop in fit, but everything else looks good to me - one whose tested many vintage 11" AR woofers over the years. 4 ohm, low Qts, DCR of 3 ohms. The FR looks like the 500 hz xover point will work. Power handling is also excellent. 200 watts RMS.

Now for the bad news. It's priced at over $500. Oh, and that's each.

https://www.madisoundspeakerstore.com/approx-11-woofers/scan-speak-28w/4878t-revelator-11-subwoofer/

 

Carl, even if it would work,  it is too small for the AR-3/3a opening.  It is 279.9 mm (11-inches) in diameter, and the AR woofer is 12-inches in diameter except along the flat sides, so it would never work without some sort of special flange.  

It's also a massive, subwoofer-type driver and as such is designed for a very low crossover into the midrange.  It has output well into in the low midrange area, but it is very peaky and rough up there—as much as 10 dB rise at 1000 Hz—thus it would probably sound terrible above 200-300 Hz.  In contrast, the standard AR 12-inch woofer is +/- 1.5dB from 38-1000 Hz.  It is also highly overdamped (-3dB at 45 Hz in a sealed 1.5 cu. ft. enclosure vs. -3dB at 35 Hz for the AR woofer in the AR-3/3a).   It would add little and take away a lot. 

I think this woofer would be far better suited for its own custom enclosure with a dedicated equalized amplifier and crossover network.  This same question was raised about using the NHT-1259 woofer (NHT 3.3 woofer) in the AR-3/3a.  It would work, but it wasn't perfectly suited. 

 —Tom Tyson

[Carlspeak]

Of course Tom, nothing but a clone of the original 3a woofer would be 'perfectly suited'. However, for the knowledgeable modder, I think the SS woofer could be made to work fine in the 3a cabinet with an adapter ring. I made many rings for small OD 3a replacement tweeters such as the Seas unit that was a part of my Super-Mod kit. I did neglect to mention in my initial post there would indeed need be some modifications made to the original woofer to mid xover section. At a minimum, the woofer would need a 2nd order or even 3rd order xo to approach the 500 hz xover point in order to cancel out the cone edge breakup modes above 500 hz. However, dropping it a couple of 100 hz wouldn't be a deal breaker IMHO.  

Almost every 3 and 3a I restored, had a Fb of about 40 hz. Haven't taken the time to model the SS. But it would be close. The long stroke of the SS woofer and it's operating frequency range would make it hard to tell in a blind listening test vs a 3a woofer with music which woofer was any 'better' than the other to the average listener. 

So, here I'm wandering in to the CSP mods area. Sorry. I wouldn't protest that move if GeneK decided it was justified.

[genek]

As long as the discussion is about a driver's suitability as a replacement, it's fine here. Once the discussion shifts to "improvements," it'll go to the mods forum.

[tysontom]

15 hours ago, Carlspeak said:

Of course Tom, nothing but a clone of the original 3a woofer would be 'perfectly suited'. However, for the knowledgeable modder, I think the SS woofer could be made to work fine in the 3a cabinet with an adapter ring. I made many rings for small OD 3a replacement tweeters such as the Seas unit that was a part of my Super-Mod kit. I did neglect to mention in my initial post there would indeed need be some modifications made to the original woofer to mid xover section. At a minimum, the woofer would need a 2nd order or even 3rd order xo to approach the 500 hz xover point in order to cancel out the cone edge breakup modes above 500 hz. However, dropping it a couple of 100 hz wouldn't be a deal breaker IMHO.  

Almost every 3 and 3a I restored, had a Fb of about 40 hz. Haven't taken the time to model the SS. But it would be close. The long stroke of the SS woofer and it's operating frequency range would make it hard to tell in a blind listening test vs a 3a woofer with music which woofer was any 'better' than the other to the average listener. 

So, here I'm wandering in to the CSP mods area. Sorry. I wouldn't protest that move if GeneK decided it was justified.

Carl, I tend to be a purists on these things, and it's not always the best approach I must admit!  The 28w Scan-Speak woofer is expensive but very impressive and has most of the other parameters close to the AR-12W woofer, and it would be literally bullet-proof with any kind of input power.  It does seem very over-damped to me (too much magnet), but it could certainly be made to work!  If it could be made to operate flat down to resonance in the 3/3a cabinet, that would be a good thing along with a lower mid-crossover, but the 3a midrange can't go much lower.  Some interesting challenges.

--Tom 

[Aadams]

Aside from the adaptor ring would there be mods to make this woofer a useful replacement as an AR1 W in a 3 cabinet?  Would it provide good performance, in your opinion, connected in a 3 cab with no mods in a bi amp config using a DSP amp to cut the Freqs above say 300hz?

 

[Carlspeak]

Give me a few days to run a model or two. On the face of it, your idea seems very doable. 

[Carlspeak]

I modelled the SS woofer in a 1.48 cu. ft. cab (st'd 3a size) using Bass Box Pro. It gives a pretty good indication of what to expect with your proposed application.

Box Q is 0.5 with heavy stuffing (I use this option for acoustic suspension speakers figuring it's the type of density found with good stuffing practice) Just be sure to use fiberglass for best results

F3 is 51.6 F10 is just over 22 hz.  Note that F3 can be lowered a bit and Q raised by reducing the stuffing

Acoustic power limit is 109 dB

System impedance stays low out to 1 kHz 

I can scan in a 2 pg summary of the numerical output and 6 graphs. PM me with your email address.

 

[Aadams]

So it would need perhaps a 6db equalization slope to be flat to 32hz?  You have me thinking about other possibilities.  Any future questions from me on this will be in mods and tweaks.

 

[Carlspeak]

Equalize to your heart's content!  

[genek]

Might be better to consider this as an AR-9 series replacement. Only $2000 to replace the woofers in a pair of speakers!

[Aadams]

This woofer frame diameter 27.9 cm is very close to Advent woofer diameter. I no longer have Large Advents so I can't measure.  Would the NLA woofer hole accommodate this woofer?  Does anyone here know?  This is very close to mods and tweak territory.