[Squidspeak]

Hey Squid,

The Hestia Grand? I think she will like that!

No problems with the plate amps concerning crossover points, as the active x/o is independent of the impedance load the amp sees. What's not independent however is the amount of power the amp will produce at either 4 or 8 ohms. A 500 watt amp may produce 500 watts @ 4 ohms but may only produce a little over 250 watts @ 8 ohms. Therefore two separate amps at 8 ohms per side, may not "see" much more power than two 8 ohm drivers wired in parallel to one amp (4 ohms total), if that makes any sense? 

You may want to give some thought to the baffle dimensions with the PA310. The PA310 (a 12" bass driver) is larger and will require more real estate to address dipole cancellation. The 15" wide baffle may not work in your case... you may need to look at an 18-20" width instead which may also negatively impact the speakers imagining characteristics up top. The 12" drivers Fs is only 2 Hz less than the 10", so you will likely not notice any deeper bass, although it will move a larger slug of air. It also has a higher MMS rating which will likely result in more baffle noise (vibration).

I would encourage you to experiment with the design. Just wanted to point out a few things so you don't wind up paying more and getting less.

Well what I was considering was a tapered baffle and the top part would mantain your exact layout,the bottom would taper just enough to fit the 12" woofer.
I appreciate your opinion and  don't want to mess with a great design already just
asking if for a little mo $$ could I get a little MO output on the bottom, Thanks Mike

[matevana]

I like the idea of a tapered baffle if you are considering a 12" LF driver. Also, Have you considered two 10's as an option? This would allow you to keep the same baffle width and raise the mid/tweeter pair to a more normal seated height. I would be tempted to use all MCM drivers in that case, taking advantage of the quantity pricing on 4 or more. I just built a 2nd Hestia for someone else using the MCM driver in lieu of the Dayton. They measure extremely close, to the point where it's hard to justify the difference in cost. Also remember to look for promo codes. These will often save you 10-15 percent and sometimes free shipping.   

[sjhomey]

I very much like your design and appreciate your design philosophy. I plan to build a pair. I read another thread where you responded to someone who wanted a top end to go with his subs. You recommended the top end of the Hestia. Another poster recommended using the SEOS waveguide and Denovo DNA-360 CD with a "pro 12 inch woofer". I have the SEOS and Denovo and have been looking for weeks for an OB design incorporating them or similar parts. I understand how the bottom end of the Hestia could fairly easily be substituted but could the Vifa tweeter be replaced with the SEOS waveguide and Denovo CD without totally redesigning the project? The DNA-360 is SPL: 108db 1W/1m and the crossover is minimum 1000hz. It is similar to the B&C DE-250. I could provide more info but since this is my first post I probably shouldn't be touting other sites.
In any case I will be buying the Vifas when PE has them back in stock and buy three pairs of the very affordable MCMs to lift the tweeter and mid a little higher off the floor. Thanks for a very interesting plan.

[matevana]

I very much like your design and appreciate your design philosophy. I plan to build a pair. I read another thread where you responded to someone who wanted a top end to go with his subs. You recommended the top end of the Hestia. Another poster recommended using the SEOS waveguide and Denovo DNA-360 CD with a "pro 12 inch woofer". I have the SEOS and Denovo and have been looking for weeks for an OB design incorporating them or similar parts. I understand how the bottom end of the Hestia could fairly easily be substituted but could the Vifa tweeter be replaced with the SEOS waveguide and Denovo CD without totally redesigning the project? The DNA-360 is SPL: 108db 1W/1m and the crossover is minimum 1000hz. It is similar to the B&C DE-250. I could provide more info but since this is my first post I probably shouldn't be touting other sites.
In any case I will be buying the Vifas when PE has them back in stock and buy three pairs of the very affordable MCMs to lift the tweeter and mid a little higher off the floor. Thanks for a very interesting plan.

Hi Peter,

A few things come to mind, the first of which is level matching the CD to the MCM mid. Assuming you are staying with one mid driver, you should expect to fabricate an L-pad with about 20dB of attenuation. You will want to get down to around 88dB @ 1w/1m, slightly higher if you plan to use more than one mid. The crossover point and slope in the original schematic should not be a problem for the Denovo.

Can you provide some information on the SEOS waveguide? Depending on the driver, you sometimes have to EQ back to flat once coupled to the WG, or you may wind up with a bit of a peak somewhere to deal with. I'm assuming others have used this combination in other projects, so that is probably already addressed (if it's even an issue). Off axis response may also be different as a result of the guide. Sounds like an interesting project. Please keep me informed.   

[sjhomey]

Thanks for your comments. I think I'll start with a Hestia build first and after some quality listening move on to some experimenting with the Denovo DNA-360 CD and SEOS waveguide. I thought of using two pairs of the MCMs for bass duties. They are so inexpensive. Do you think they would be more beneficial in the midrange?

More info on the CD and SEOS can be found at http://www.avsforum.com/t/1291022/hey-guys-we-need-a-little-rallying-here and also http://www.diysoundgroup.com/. While the focus of this group is building boxes I did find this link http://www.aespeakers.com/phpbb2/viewtopic.php?f=14&p=13897#p13842. I think the LO15 has been replaced by the AE Dipole 15 http://www.aespeakers.com/drivers.php?driver_id=32. The 15" version has an SPL of 1WSpl: 90.1dB. I believe the Hawthorne Audio Sterling Silver Iris OB 15" Coaxial Unit uses a Radian CD. All of which is to say that I think some are building OBs with waveguides and CDs. I take your point that there would need to be quite a bit of attenuation.

First things first. I'll build the Hestia and even though going into the CD/waveguide realm is probably way past my abilities I might give it a try. I wonder if the controlled directivity of the waveguide might not be a good complement to the OB concept. I'm sure I'll have a few questions about the Hestia build in the meantime.

[matevana]

Completely agree with starting with the Hestia build, as the design is fairly easy to replicate. I think you will like it as-is. Many of the concepts you mention may in fact enhance the design. The Neo Note as an example, makes use of two lower-mids, so two MCM drivers would not be out of the question, but due to the 10" diameter and high sensitivity, probably less desirable. At a minimum it would change the design, and require tinkering with crossover points, levels, etc. (and not a bad project once the design is built). Remember that one of the primary Hestia design goals was a well balanced, no shout design. A 2nd mid driver would surely alter the sound characteristics, for better or for worse.

I do believe there is much to be said about wave guides in dipoles, as a natural compliment to their radiation pattern. I personally would experiment with high quality silk dome tweeters in waveguides, as opposed to CD's. You dont need the SPL's in this configuration and the curves are usually much smoother. You may even look at a small (2-3") full range cone drivers in a WG, and have true dipole radiation up through the highest octave. You could theoretically have a guide on both sides of the driver    

[Squidspeak]

I like the idea of a tapered baffle if you are considering a 12" LF driver. Also, Have you considered two 10's as an option? This would allow you to keep the same baffle width and raise the mid/tweeter pair to a more normal seated height. I would be tempted to use all MCM drivers in that case, taking advantage of the quantity pricing on 4 or more. I just built a 2nd Hestia for someone else using the MCM driver in lieu of the Dayton. They measure extremely close, to the point where it's hard to justify the difference in cost. Also remember to look for promo codes. These will often save you 10-15 percent and sometimes free shipping.

Matavena, I have purchased the MCM and Vifa drivers but am considering a 15" for the bottom in
a tapered baffle to fit it. Would the DAyton PA380 be a viable driver to mate with the top end? I know people swear by the Eminence Alpha 15 but the FR. and FS are lower on the Dayton, whats your opinion?

[pureiso]

Just a question to those who may know the answer.

I have been looking at possibly using this: http://www.parts-express.com/pe/showdetl.cfm?partnumber=310-308

This would be keeping with the low cost solution, and may assist those looking for a way to power the low end.  I do not have the stuff for the kit, but maybe someone could throw this in (only $27, keeping my fingers crossed) and test it out.

I may be picking up this tiny amplifier soon, so I may be able to report on it.

[matevana]

Matavena, I have purchased the MCM and Vifa drivers but am considering a 15" for the bottom in
a tapered baffle to fit it. Would the DAyton PA380 be a viable driver to mate with the top end? I know people swear by the Eminence Alpha 15 but the FR. and FS are lower on the Dayton, whats your opinion?

Hey Squid,

Can I ask how you plan to drive the PA380?

[matevana]

Just a question to those who may know the answer.

I have been looking at possibly using this: http://www.parts-express.com/pe/showdetl.cfm?partnumber=310-308

This would be keeping with the low cost solution, and may assist those looking for a way to power the low end.  I do not have the stuff for the kit, but maybe someone could throw this in (only $27, keeping my fingers crossed) and test it out.

I may be picking up this tiny amplifier soon, so I may be able to report on it.

That amp will not drive the low end in OB with any authority. Possibly the top.

[Squidspeak]

Hey Squid,

Can I ask how you plan to drive the PA380?

The same way as the original design, maybe just the next size up amp. Still mono for
the bass drivers (8 ohm drivers) Crossover just like the original design  but making the baffle
wider on the bottom to fit the 15". I love the design but wondering if it would be possible to
make a single baffle to be truely full range w/o the need for a sub?

[matevana]

The same way as the original design, maybe just the next size up amp. Still mono for
the bass drivers (8 ohm drivers) Crossover just like the original design  but making the baffle
wider on the bottom to fit the 15". I love the design but wondering if it would be possible to
make a single baffle to be truely full range w/o the need for a sub?

Total Q is fairly low on the Dayton 15" Pro Sound, which is why I asked. I believe it will be a better sounding driver than an Alpha, but you should consider a separate sub amp with built-in boost, around 6dB in the 30-40Hz range. The driver's lower Fs will probably not benefit you as much, but if you can compensate for the low Qts electronically, you should be fine.

[Squidspeak]

Total Q is fairly low on the Dayton 15" Pro Sound, which is why I asked. I believe it will be a better sounding driver than an Alpha, but you should consider a separate sub amp with built-in boost, around 6dB in the 30-40Hz range. The driver's lower Fs will probably not benefit you as much, but if you can compensate for the low Qts electronically, you should be fine.

Are you suggesting something different than the Yung amp? I thought just more watts with
same boost/features to power the bigger driver

[matevana]

Are you suggesting something different than the Yung amp? I thought just more watts with
same boost/features to power the bigger driver

Sorry Squid, didn't remember our previous conversation. That combination should integrate well. You should be able to achieve slightly higher SPL's than the original design. Almost all dipole designs will ultimately be limited by the capabilities of the low frequency driver(s) and its ability to "keep up" with the rest of the system. I am very interested to hear your listening impressions when the design is complete.

[Squidspeak]

Matevana,I just wanted to make sure that the Dayton 15 had the right parameters for OB
Everything else will follow your design, I will let you know how things progress.

[matevana]

Matevana,I just wanted to make sure that the Dayton 15 had the right parameters for OB
Everything else will follow your design, I will let you know how things progress.

I'm really stoked to hear about your design. Please consider doing a build thread so we can follow. You will be the 5th person that I am aware of to build some form of the Hestia. I have to say that they have all been extremely pleased, especially considering the cost.

[Squidspeak]

I'm really stoked to hear about your design. Please consider doing a build thread so we can follow. You will be the 5th person that I am aware of to build some form of the Hestia. I have to say that they have all been extremely pleased, especially considering the cost.
I actually got together with sjhomey (he is also doing a build) and swapped drivers, I had an extra pr.
of tweeters and he had an extra pr. of the MCM mids so it worked out great and will do a thread when
I get started building. Thanks for a great design

[matevana]

I actually got together with sjhomey (he is also doing a build) and swapped drivers, I had an extra pr.
of tweeters and he had an extra pr. of the MCM mids so it worked out great and will do a thread when
I get started building. Thanks for a great design

That's awesome. Cant wait to get your listening impressions. Where are you guys located?

[Squidspeak]

The 51st state, South Jersey

[matevana]

The 51st state, South Jersey

Haha... I'm in S. Florida, which is eventually where all people from Jersey wind up. I dont know of any OB folks down here.