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Pete B

Not an AR 1.5" Midrange

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Look, it fits the AR 1.5" midrange cutout.

It has a .75" tweeter and a mystery 1.5" midrange under that dust cap!

AR-NOT-MID.jpg

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They finally got the driver layout right here:

 

AR-78.gif

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On 8/1/2018 at 9:33 AM, Pete B said:

its the AR 1.5" midrange cutout.

It has a .75" tweeter and a mystery 1.5" midrange under that dust cap! 

Are we going see progress on this beast or is the experiment over? 

Adams

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I demoed them in AR-11's at 10/20/2018 Frankenfest in Sutton MA and at the 9/15/2018 Blue Mountain

audio fest in NY - not much interest.

I will continue to work on them as time permits.

It would be nice to A/B them with a stock pair of AR-11's but I don't have a second pair.

NOT-AR-11-FRONT-SM.thumb.jpg.c9782084237d3014fdec20bff3c3ff68.jpg

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3 hours ago, Pete B said:

I will continue to work on them as time permits.

Do you have a pair of 3as or 5s or any classic model with a jumper?   Have you tried mounting in its own box to make it modular?  What is the impedance of the unit in standalone config? What is the practical low frequency cut off?

 

Adams

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No, I don't have any other AR 12" classic models, I do have 2ax and 2a boxes.

No have not mounted them in any other box.

I can set they up as 4 or 8 ohms.

The mid has the same radiating area with more than double the throw and I could

set it up for as low as 300 Hz but in this application I tune for the same Fc as the AR mid.

 

I see your point, If I had biamp wired AR-11s I could run them externally sure that would work.

I'll consider setting up these AR-11's for Biamp input.

Simplest thing would be for someone to bring a clean pair of restored AR-11s to the next fest.

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Can you replicate exact copies in appearance and performance on demand?   For instance if wanted a pair, what would be the cycle time from order to outbound shipping?  And If wanted 4 more later would the cycle time be the same?

That tweeter resembles a JBL ring radiator.   Would you characterize the dispersion of your entire unit as wide or narrow?

Adams

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I have an .STL file ready to try to 3D print it but I have to get to the library to try it out.

The prototype is done in wood and it is very time consuming to make so I have

hopes for the 3D printed version.

I've not done enough testing to say that it is ready to go, but I have parts to do 2 more

pairs and would need the plates 3D printed.  I would say realistically 2 - 3 weeks depending

if I have to order parts or not and if the 3D printed version works out.  Otherwise when I 

route the plates for example it is easy to do half a dozen or more extras once set up but then there

is all the rest of the cutting, drilling, painting, etc.  You asked for an exact copy, my plan was

to leave out the small mouting screws for the drivers and to use black caulk/glue to hold 

them in - any opinion on this?

But I want to finalize the design before moving forward, and I don't have a time table for it. 

I'll probably set up the AR-11s for biamping and then A/B demo them at the next Frankenfest

in March.

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3 hours ago, Pete B said:

to leave out the small mouting screws for the drivers and to use black caulk/glue to hold 

them in - any opinion on this?

For my purposes this would be ok.  But, if you are 3D printing how hard would be to add a screw hole pattern that matches an AR?  Of course it looks easy to someone who can't 3D print.

You forgot to answer my question regarding dispersion. 

That tweeter resembles a JBL ring radiator.   Would you characterize the dispersion of your entire unit as wide or narrow?

Adams

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The large 1/4 - 20 screws around the perimeter will remain, I'm talking about the 4

that you see around the tweeter, those would be replaced with caulk/glue.

I expect dispersion to be about the same up to 10 KHz based on the diameters being

the same.  The tweeter is slightly recessed that will alter the dispersion in the top octave.

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On 1/20/2019 at 10:44 AM, Pete B said:

I do have 2ax and 2a boxes. 

I am sure you have seen an AR2ax with the econowav horn mod.  It occurred to me, by comparison, yours would be a genuine upgrade that would rival an AR5.  Your driver panel would be a near drop in mechanical fit and you could specify the coils and caps to install beside and around the existing network to set the proper crossover frequencies.  In other words it might be possible to make the mod reversible.  You would know better than I.  Just thought I would throw it out there.

Adams

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An AR-2ax has a smaller midrange cutout, so it would require a different plate.

That is an interesting idea but I don't know if there is much of a market for it,

Probably more for boxes that are parted out where someone wants to make the

empty boxes functional again.

Did you notice that with the mid and tweeter vertically in line one can rotate the plate

90 degrees when using the speakers on a bookshelf?

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I've not looked too hard for places to 3D print, but the CO-OP in New London CT can only 3D 

print objects that are about 4" on a side, this is 5.75" in diameter.  The library has one that 

will do about 9" on a side.  New London is a bit far so I'm going to look closer to my area.

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32 minutes ago, Pete B said:

An AR-2ax has a smaller midrange cutout, so it would require a different plate.

Yes I thought so.  I was thinking either hole could be used with the plate lapping over and a mortite seal.  Of course if you can make interchangeable plates to order that would work.  IMO If had an orange tweeter 2ax that was broken your unit would be my choice to upgrade the whole speaker system to AR5 performance. I know there is a difference, both  in spaciousness and mid range control,  because the AR5 permits adjustment of the dome mid range down to almost 1khz lower in range than the AR2ax.  When I was a bright green AR tyro I still had some 73 model 2axs that I wanted to upgrade to AR5s.  It can't be done without butchering the cabs.  Your tandem unit would make it easy by comparison and possibly reversible.

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I got an online quote to make the plate from what looks like a high end service.

If I let them quote it lowest cost, I'm not sure exactly what I'm getting but the 

price per single plate was $34.

I think the low cost might be based on letting them use the default filament that is

loaded into the machine since I could not specify a color or material type.

If I changed it to a specific material such as ABS with black for color the price per 

plate jumps to about $50.   Not very practical.

I suppose that I could have them CNC cut from wood to save my time.

Or if there was enough interest I'd make a jig to locate holes etc. and speed up my

own work.

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The tweeter is not a ring radiator, rather it is a .75" soft dome type.

This is a ring radiator, the center is fixed:

ot19nc00.jpg.7932c2166de7fc0a01269064a2df2ef4.jpg

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2 hours ago, Pete B said:

The tweeter is not a ring radiator, rather it is a .75" soft dome type.

This is why I asked.  You probably know the one on the right is an 075 ring radiator

image.png.877b288143b2b82dddfc62d7205ab46a.png

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The center on that JBL doesn't move, so yes they are very different.

3D printers have come way down in price, a decent one is $200 to $400.

A bit about getting started:  https://www.youtube.com/watch?v=Sqh3FM12KVg

The Ender-3 is on sale for $200:  https://www.youtube.com/watch?time_continue=1&v=Tso0aC3DXUE

 

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On 1/20/2019 at 10:44 AM, Pete B said:

I do have 2ax and 2a boxes.

Didn't you just sell your 2ax woofers.  I thought I remembered a listing but I can't find it.  Maybe you didn't sell them.  Fate can be cruel.

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Yes,  I sold the woofers but have Peerless 1727 10" that drop in.

What state are you in, any chance of going to Frankenfest?

I also have empty Large Advent boxes that I think would take the AR 12" woofer,

but then I'd have to copy the AR-11 crossover.

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900 miles to Frankenfest.

Just my opinion but I am thinking that the best showing for your dual driver would be against a 2ax and an AR5. If your unit will match an AR5 to 10khz then every 3 way 2 series out there is a potential AR5 equivalent with zero cabinet butchery. 

Proving that an AR11 can sound as good or marginally better than a stock AR11 if you have the right program material would be an achievement of course but there are just too many available replacement mids and tweeters for ADD models.  

With skills like yours,  you could create a conversion for Large Advents, making them a 3 way with just two holes in the cab.  There is plenty of room for more crossover in the box and the Advent woofer would be great cut off at 400hz.  A genuine 3a rival without the beamyness and harshness.

RE: Frankenfest.  If you modded a 2ax pair I am sure someone would volunteer to bring some 2axs to compare.  If it really is AR5 level performance, the difference in the mod and the standard 2ax will be very obvious when playing music recorded live in a large venue. 

Just my opinion. 

Adams

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Thanks for your thoughts, something to consider.

The thing about upgrading AR-2 series systems is that they'd also need a mostly new

crossover including on the woofer - much more cost.  And then the 2's having the smaller

woofer will never reach the performance level of the 12" versions.

If I had 2's and wanted a simple but effective update, I'd add a modern cost effective

high performance tweeter and get rid of the midrange that is really a cheap cone tweeter.

Something I wondered for a long time now is if there was a woofer on a 10" frame that provided

the performance of the Large Advent woofer.  I considered the Advent Legacy and need to test

those woofers, series 1 and 2, and then read the spec sheet on the BA A100 showing a system

Fc of 42 Hz as seen here which is a match to the LA and AR 12":

 http://www.classicspeakerpages.net/IP.Board/index.php?/topic/10477-boston-acoustics-a100-versions/&tab=comments#comment-123007

 

The BA woofer would be an excellent upgrade to the AR2 series speakers in my opinion, but I'm

not sure if the woofers are as robust as the LA woofer on the 12" frame.  The LAs with the thick

alloy voice coil formers are very rugged drivers.

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You would know far better than I about the degree of cost and effort required to electronically convert a 2 way to a 3 way and a 2ax to a 5 series  To me , it seems the ideal would be a straight drop in replacement like what you have now but the addressable market could be quite large if you could get into the 2 series world.  How about an AR3t like version that sits atop classic boxes, connects to the tweeter terminal and picks up for the mid where the woofer rolls off?  Making the 2ax sound better than it does based on historical sales, is a bigger market than filling the holes in abandoned 12” cabs, though if your mod caught on those 12’ boxes would suddenly have value beyond the shipping cost.  

Whatever you use as a test mule IMO needs to be a pair.  2 series cabs are lighter and smaller but whatever you use should be at Frankenfest prepared for a “shootout” against a worthy target and you need to know the results of the test before you arrive.  

If I were there to judge I would need an AB comparison.  Your version would need be just as smooth and spacious sounding as the stock version and I would expect it to have a slightly more delicate and clear sound than the AR mid……  More spacious than a 2ax and equally spacious as an 11.  Getting spaciousness equal to properly working 3a or 5 would be astounding, nice and unexpected IMO.

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I'll take that all into consideration.

I would certainly do the A/B test at home first.  I even have 12" AR woofers from my AR-9s that

I could borrow for another box.

Another interesting use for this plate is in the AR-9 that has such wide spacing of the mid and tweeter.

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I think you could be on to something.  The 9 could be viewed as a high powered AR5 with an advanced and well integrated passive sub woofer.  Internally the woofer area is isolated by packed stuffing and they could have been two stacked  or separable units except they would have cost even more.  So I agree your dual driver should work in a 9 if it all goes according to plan.

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