# Exodus Anarchy 2-way bookshelf



## dyohn (Apr 17, 2008)

Many people are working up design ideas using the new Exodus Audio Anarchy 6.5" midwoofer, I among them. I have not built these yet and probably will not be able to until later this summer, but if you are itching to try a design with the Anarchy woofer, I offer these for your consideration.

Here is the first one that I think is ready. It's a 2-way bookshelf monitor using one Exodus Anarchy plus one Parts Express 275-070 Dayton DC28F 8-ohm silk dome tweeter. I chose this tweeter because it is a decent performer and is on sale as of this writing for only $13 each. Any 8-ohm tweeter with fs of less than 1 KHz will work in this design, with attention paid to the L-pad value to drop it to approx. -3db below the Anarchy's sensitivity range of 85db. This design should create a good critical music monitor.

The design was based on using either the Parts Express 0.38 cuft pre-made enclosures in a sealed alignment (creating a Qtc of about .63 and an fb of 64Hz) or the Parts Express 0.5 cuft pre-made enclosures in a sealed alignment (for a Qtc of 0.58 and Fb of about 58Hz.) Alternately, the 0.5 cuft enclosure can be ported @ about 41.5 Hz to extend the low frequency response. Venting should be accomplished with a port diameter of at least 2.5" (14" long) and in the PE cabinets would be a rear-exit vent. This does create a problem since the PE enclosures are only 13" deep so the port will have to be bent to fit. Using a smaller diameter such as 2" @ 8.5" long will create the proper port tuning but also creates significant port noise over a broad band around the tuning frequency if the system is pushed hard. Both drivers should be flush mounted along the center line of the front baffle.

Of course the builder could design their own enclosure geometry and the only thing that would need to be changed in the crossover design is the BSC filter. This design uses a front baffle that is at least 8" wide (as in the PE enclosures.)

The crossover topology is a 3rd order electrical filter and incorporates a Zobel on the woofer and a fixed pad on the tweeter. The fixed pad attenuation is intended to create a bit of a laid-back sound. A variable L-pad rated at 8-ohms could be substituted for the fixed attenuator if the designer wants to be able to adjust the high frequency level to better suit their taste.

For the crossover, I’ve made a list of target component values and suggested part numbers from Parts Express, targeting good performance at mid-level cost. I’ve also listed an alternate lower-cost solution for the larger air core inductors if you are on a tighter budget. I suggest using no smaller than 15 AWG inductors for the woofer network, and using good quality poly caps for the tweeter network. The builder may decide to use foil inductors if you see fit. Also, I prefer to stack caps instead of using single large values and have listed the parts accordingly. All resisters are Mils 12W non-inductive. Each builder may decide to follow their own beliefs and preferences concerning these parts. NOTE the power rating of the BSC resister R3 is approx. 1/3 the rating of the woofer. This is created using an array of four 4-ohm 12W resisters. The crossover schematic is attached.

Woofer network values:

L1: 0.7 mH
L2: 0.4 mH
L3: 0.6 mH
C1: 13.6 uF
C2: 15 uF
R2: 8 ohms
R3: 4 ohms @ 48 watts

Tweeter network values:

C3: 8.67 uF
C4: 18.67 uF
L4: 0.13 mH
R1: 2 ohms 
R4: 4 ohms

Proposed parts list:

L1: 266-335 (alternate 255-414)
L2: 266-320 (alternate 255-406)
L3: 266-330 (alternate 255-412)
L4: 266-802

C1: 2x 027-424 in parallel
C2: 2x 027-429 in parallel
C3: 027-564 + 027-836 in parallel
C4: 2x 027-566 + 027-836 in parallel

R1: 005-2 
R2: 005-8 
R3: 4x 005-4 (two in series, two sets of two in parallel)
R4: 005-4 

Other parts you’ll need include 16 AWG or larger speaker wire, speaker wire binding posts, and if you decide to build a vented system an appropriate port.

I hope this is an interesting project for someone out there. If you build it, please post your findings and impressions. I will when I build it. Have fun!


----------



## rothnic (Jan 4, 2010)

In another thread you mentioned that you might do a different design for a dedicated surround design. I was just curious as the tradespace between a bookshelf and a surround. Would this just be size and the baffle step filter? 

It looks like modeling the sealed box size around .25 cubic feet gives a reasonable size box and decent response.


----------



## lsiberian (Mar 24, 2009)

rothnic said:


> In another thread you mentioned that you might do a different design for a dedicated surround design. I was just curious as the tradespace between a bookshelf and a surround. Would this just be size and the baffle step filter?
> 
> It looks like modeling the sealed box size around .25 cubic feet gives a reasonable size box and decent response.


For a surround I'd think a wall mount is most likely as such baffle step would be unnecessary.


----------



## dyohn (Apr 17, 2008)

Yes, the surround will not need BSC. It's a monopole woofer with switchable bipole/dipole tweeters in about a .25 to .3 cuft enclosure. It will be the last one I post but probably the first one I actually build.


----------



## lsiberian (Mar 24, 2009)

Good work BTW I hope some folks will take advantage of your effort.


----------



## 1Michael (Nov 2, 2006)

Those Anarchys are nice looking drivers with there hefty magnets. I have liked the idea of large magnets going back to the old Altec Lansing days.
If I had a job, I would build these just for fun because I do like that soft dome tweeter:T

Do you have a MTM brother in the works for this project? I got a buddy that might be interested in a diy project soon...


----------



## lsiberian (Mar 24, 2009)

buggers said:


> Those Anarchys are nice looking drivers with there hefty magnets. I have liked the idea of large magnets going back to the old Altec Lansing days.
> If I had a job, I would build these just for fun because I do like that soft dome tweeter:T
> 
> Do you have a MTM brother in the works for this project? I got a buddy that might be interested in a diy project soon...


With the ability of these drivers. I think an MTM would be unnecessary. This is an XBL^2 motor system. But you could easily modify the attenuators to allow for it in this design.


----------



## dyohn (Apr 17, 2008)

lsiberian is right, the Anarchy output is quite good, but the sensitivity is pretty low so an MTM @ 4-ohms and 88db sensitivity might be more appealing for HT applications. I have an MTM coming next - maybe today. I'm playing with venting the PE 0.75 cuft enclosure and trying a series Xover design that I think might be fun for people to build...


----------



## rothnic (Jan 4, 2010)

dyohn said:


> lsiberian is right, the Anarchy output is quite good, but the sensitivity is pretty low so an MTM @ 4-ohms and 88db sensitivity might be more appealing for HT applications. I have an MTM coming next - maybe today. I'm playing with venting the PE 0.75 cuft enclosure and trying a series Xover design that I think might be fun for people to build...


Yes, I'm definitely interested in a MTM type setup for the anarchy for fronts. I am also curious about a possible reference to the math behind the sensitivity calculations when adding multiple drivers. I am a EE so can understand the math, I just can't find a reference.

Can most modern receivers handle a 4 ohm load?


----------



## rothnic (Jan 4, 2010)

As a budget kit for surrounds or bookshelfs, http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-640, looks like a good value. You get some crossover that could be modified, the boxes, and tweeters. Then you can just drop in the anarchy.


----------



## dyohn (Apr 17, 2008)

rothnic said:


> Yes, I'm definitely interested in a MTM type setup for the anarchy for fronts. I am also curious about a possible reference to the math behind the sensitivity calculations when adding multiple drivers. I am a EE so can understand the math, I just can't find a reference.
> 
> Can most modern receivers handle a 4 ohm load?


Here's the proposed MTM design: http://www.hometheatershack.com/forums/diy-speakers/26720-exodus-anarchy-ht-oriented-mtm.html

As far as the math behind sensitivity calculations, try here: http://www.sengpielaudio.com/calculator-efficiency.htm

Most receivers are only rated to 6-ohms. Some (so-called "high current") receivers can handle 4-ohms, and almost any solid state separate amplifier can handle 4-ohms. The Anarchy is actually closer to a 10-ohm nominal speaker, so the MTM is actually more like 5-ohms instead of 4.


----------



## 1Michael (Nov 2, 2006)

rothnic said:


> As a budget kit for surrounds or bookshelfs, http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-640, looks like a good value. You get some crossover that could be modified, the boxes, and tweeters. Then you can just drop in the anarchy.


As a general rule you 'Cannot' substitute drivers in any design unless the TS parameters are exactly the same as the design calls for. There are a few exceptions.


----------



## rothnic (Jan 4, 2010)

buggers said:


> As a general rule you 'Cannot' substitute drivers in any design unless the TS parameters are exactly the same as the design calls for. There are a few exceptions.


Yes, you would have to modify the crossover, like I said. For example, the zobel network calculation is very straight forward. The Re is the same for both drivers, and obviously the tweeter is the same, however the Le is different so many values would change.

The point is that you get 2x $13 tweeters, at least some crossover components you may be able to reuse, the foam to line the boxes, the actual enclosures, the board to mount the components on, etc for $120. All the little things that will add up in the end.

My only reserve is that I need surrounds, and those enclosures are .50 cubic feet.


----------



## rothnic (Jan 4, 2010)

dyohn said:


> Here's the proposed MTM design: http://www.hometheatershack.com/forums/diy-speakers/26720-exodus-anarchy-ht-oriented-mtm.html
> 
> As far as the math behind sensitivity calculations, try here: http://www.sengpielaudio.com/calculator-efficiency.htm
> 
> Most receivers are only rated to 6-ohms. Some (so-called "high current") receivers can handle 4-ohms, and almost any solid state separate amplifier can handle 4-ohms. The Anarchy is actually closer to a 10-ohm nominal speaker, so the MTM is actually more like 5-ohms instead of 4.


I understand that the receiver would see each load separately when producing the respective frequencies for them. So do you take the larger current consuming drivers into account as the impedance of the overall speaker? I assume this is why you consider the speaker as having the impedance of Anarchy||Anarchy, instead of Dayton+(Anarchy||Anarchy).

However, even with the tweeter not being the primary load, would the impedance of it not add anything to the parallel anarchies in normal listening. I can understand that if you were playing back 95hz sine waves this would not be good for the receiver, but I'd like to understand the concept further.


----------



## dyohn (Apr 17, 2008)

One of the purposes of a crossover is to direct the signal to the appropriate driver(s) based on frequency. Id does this by attenuating the signal to one while increasing the signal to the other and holding a flat (normally) impedance curve while doing to. The net impedance of the system is never (normally) lower than the lowest impedance of any given driver. In an MTM with two woofers or mids in parallel, the lowest system impedance is created by them.


----------



## Ryan Anderson (Jul 20, 2009)

David, I completely missed these threads though you specifically stated them in the Anarchy Review thread. Thank you very much for all of your work! What does final cost come in around for one of these?


----------



## Ryan Anderson (Jul 20, 2009)

Ryan Anderson said:


> David, I completely missed these threads though you specifically stated them in the Anarchy Review thread. Thank you very much for all of your work! What does final cost come in around for one of these?


I'm sorry to press, I'm just anxious to make my purchases and get moving  Again, I'm very greatful!


----------



## dyohn (Apr 17, 2008)

I have not yet priced the components, but I listed suggested part numbers from Parts Express so you should be able to look them up and make your own estimate...


----------



## devinkato (Sep 6, 2011)

Sorry to bring up a dead thread, but I haven't been able to find any 2-way Exodus Anarchy designs that have been actually built and tested. This design looks to be the way to go for me (limited budget + already have the woofers).

Has anyone built this and has any feedback?


----------

